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73 results on '"SuperKEKB"'

1. High-Luminosity B Factory e+e− Colliders.

Author

Seeman, John T.

Abstract

Three double-ring B factories—PEP-II, KEKB, and SuperKEKB—were built with asymmetric beam energies to produce high luminosity at the Υ(4S) resonance producing copious B mesons and associated particle physics data, delivered to their respective particle physics detectors, BaBar, Belle, and Belle II. In PEP-II and KEKB, the primary goal was achieved to make the first measurements of charge parity (CP) violation in decays in the B meson system. PEP-II and KEKB have finished beam operations, but particle data analysis continues. SuperKEKB is extending those measurements. The beam operation of SuperKEKB with Belle II has recently started. These three accelerators have pushed the state of the art of accelerators of two-ring colliders, including small beam emittances, small interaction point beam sizes, large stored beam currents, crab cavities, top-up injection with the detectors on, bunch-by-bunch feedbacks, crab waist operation, high beam–beam parameters, high peak luminosity, and high integrated luminosity. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Gradient Boosted Decision Tree Application to Muon Identification in the KLM at Belle II

Author

Benninghoff, Logan Dean

Subjects
GBDT, binary classifier, particle physics, high-energy physics, SuperKEKB
Abstract

We present the results of applying a Fast Boosted Decision Tree (FBDT) algorithm to the task of distinguishing muons from pions in K-Long and Muon (KLM) detector of the Belle II experiment. Performance was evaluated over a momentum range of 0.6 < p < 5.0 GeV/c by plotting Receiver Operating Characteristic (ROC) curves for 0.1 GeV/c intervals. The FBDT model was worse than the benchmark likelihood ratio test model for the whole momentum range during testing on Monte Carlo (MC) simulated data. This is seen in the lower Area Under the Curve (AUC) values for the FBDT ROC curves, achieving peak AUC values around 0.82, while the likelihood ratio ROC curves achieve peak AUC values around 0.98. Performance of the FBDT model in muon identification may be improved in the future by adding a pre-processing routine for the MC data and input variables.

Published
2024

3. Recent results from Belle II

Author

Bertacchi, Valerio, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Belle-II

Subjects
Charm, Nuclear and High Energy Physics, flavor, Dark sector, Time Dependent CP violation, B-Factory, BELLE, SuperKEKB, meson, dark matter, decay, CKM Matrix, Rare B decays, CP violation, KEK-B, CP, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Belle II, time dependence, upgrade, mediation, violation
Abstract

International audience; The Belle II experiment at the SuperKEKB energy-asymmetric e+e− collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is 6⋅1035cm−2s−1 and the Belle II experiment aims to ultimately record 50ab−1 of data, a factor of 50 more than its predecessor. With this data set, Belle II will be able to measure the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements with unprecedented precision and explore flavor physics with B and D mesons, and τ leptons. Belle II has also a unique capability to search for low-mass dark matter and low-mass mediators. In this work, I will review the latest results from Belle II.

Published
2023
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4. Cryogenic systems of SuperKEKB final focusing superconducting magnets.

Author

Zong, Zhanguo, Ohuchi, Norihito, Kawai, Masanori, Aoki, Kazuyuki, Oki, Toshiyuki, Wang, Xudong, Arimoto, Yasushi, Kondou, Yoshinari, Aoki, Kanae, Nakamura, Shu, and Yamaoka, Hiroshi

Subjects
*CRYOGENICS, *SUPERCONDUCTING magnets, *SUBCOOLED liquids, *ELECTRON accelerators, *LIQUID helium, *HEAT radiation & absorption, *HEAT conduction
Abstract

SuperKEKB is an accelerator to collide electron and positron particles with a nano-beam collision scheme and equipped with two cryostats to accommodate 55 superconducting (SC) magnets for final focusing. Each cryostat is cooled by an independent cryogenic system employing a refrigerator of 250 W at 4.41 K and a subcooler to supply subcooled liquid helium (LHe), which absorbs heat leak by the relatively small sensible heat (∼2.4 J/g) with an acceptable temperature rise of 0.35 K from 4.41 K to 4.76 K (saturated temperature at 0.161 MPa). The associated limitation of the permissible heat leaks necessitated a careful cryostat design with comprehensive thermal considerations to reduce heat conduction and radiation and maintain stable cryogenic conditions of SC magnets. This paper presents the designs of the cryostats and cryogenic systems to address the technical challenges to cool SC magnets with the compact spatial constraints. Cryogenic systems were designed to supply a subcooled LHe flow of ∼20 g/s and to provide a mixed capacity of refrigeration and liquefaction loads. The liquefaction component amounts to 40 L/h (∼1.3 g/s), approximately half of the total refrigerator capacity to cool the vapor-cooled current leads of SC magnets, which is also found to significantly influence the total LHe flow (∼20 g/s) to cool the cryostats. Dedicated studies were performed to investigate the SC magnet temperature variations with the LHe flow, the system operation modes such as cooldown and quench of SC magnets, and to assess the heat leaks with local and global methods, which facilitate the practical operation of cryogenic systems for the SuperKEKB accelerator and are detailed in this paper. • Heat leak distributions were evaluated and compared for cryogenic components. • Cryogenic systems of SuperKEKB final focusing SC magnets are described. • The subcooled LHe scheme was realized in cryogenic systems of SC magnets. • Operations of current leads are summarized for thermal stability of cryostats. • Practical operations of cryogenic systems are presented with thermal parameters. [ABSTRACT FROM AUTHOR]

Published
2024
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5. A fast luminosity monitor based on diamond detectors for the SuperKEKB collider.

Author

Pang, C.G., Bambade, P., Di Carlo, S., Funakoshi, Y., Jehanno, D., Kubytskyi, V., Masuzawa, M., Peinaud, Y., Rimbault, C., and Uehara, S.

Subjects
*LUMINOSITY, *PHOTON scattering, *DETECTORS, *DIAMONDS, *SYSTEMS design
Abstract

A fast luminosity monitor measuring the rate of the radiative Bhabha process at zero degree photon scattering angle based on diamond detectors was developed and successfully operated during the Phase-2 commissioning of SuperKEKB. The main purpose of this system, called LumiBelle2, is to provide: train integrated luminosity signals at 1 kHz with a relative precision better than 1% for luminosities higher than 1 0 34 c m − 2 s − 1 , input to a dithering feedback system designed to maintain an optimum horizontal overlap between the two colliding beams at the Interaction Point (IP), and bunch integrated luminosity signals at 1 Hz which are useful for machine tuning and beam parameters studies of the successive bunches along the train. In this paper, the design of the LumiBelle2 and Phase-2 results will be reported, including the evaluation of the single beam background, relative luminosity measurements and vertical beam size determinations at the IP using vertical offset scans. [ABSTRACT FROM AUTHOR]

Published
2019
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6. The Belle II experiment: Status and physics prospects.

Author

Shiu, Jing-Ge

Subjects
*PHYSICS experiments, *PROSPECTING, *PHYSICS, *FLAVOR, *LUMINOSITY
Abstract

The Belle II experiment at SuperKEKB e + / e − collider, Japan, is aiming at exploring flavor physics in high intensity frontier. The target instantaneous luminosity of SuperKEKB is at 8 × 1 0 3 5 s − 1 cm − 2 , which is 40 times higher than that at KEKB. The renovated Belle II detectors around the interaction point are expected to collect 5 0 ab − 1 data within 7 years. This gives high data statistics for precision measurements and probing new physics in rare decay studies. The Belle II experiment has successfully recorded the first collision events at SuperKEKB in April 2018, and is ready for physics data taking. This paper will cover the current status of Belle II and highlight its prospects on flavor physics. [ABSTRACT FROM AUTHOR]

Published
2019
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7. Das Rätsel der verschwundenen Antimaterie: Belle‐II‐Detektor misst B‐Mesonen‐Zerfall.

Author

Kiesling, Christian

Abstract

Zusammenfassung Das Standardmodell der Teilchenphysik kann trotz unbestreitbarer Erfolge wichtige Beobachtungen nicht erklären. Dazu zählt das Verschwinden der Antimaterie im Universum. Deshalb wird intensiv nach „Neuer Physik" gesucht. Parallel zu den Experimenten am LHC, der die höchsten Kollisionsenergien erzielt, hat nun eine neue Super‐B‐Factory in Japan mit dem Belle‐II‐Detektor seinen Betrieb aufgenommen. Dort sollen mit höchster Präzision die Unterschiede zwischen B‐Mesonen und Ihren Antiteilchen untersucht werden. Für Belle II wurde unter deutscher Federführung ein neuartiger Pixel‐Vertexdetektor entwickelt, der für die genaue Vermessung der B‐Meson‐Zerfälle essentiell ist. [ABSTRACT FROM AUTHOR]

Published
2019
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8. First measurements of the vertical beam size with an X-ray beam size monitor in SuperKEKB rings.

Author

Mulyani, Emy, Flanagan, John W., Tobiyama, Makoto, Fukuma, Hitoshi, Ikeda, Hitomi, and Mitsuka, Gaku

Subjects
*X-rays, *SYNCHROTRON radiation, *SCINTILLATORS, *IMAGING systems, *CCD cameras
Abstract

Abstract This paper reports first measurements of the vertical beam size using an X-ray Beam Size Monitor (XRM) for each of the SuperKEKB rings (Low Energy Ring, LER, and High Energy Ring, HER) during Phase 1 and 2 commissioning of SuperKEKB. The XRM device is dedicated to measuring the e − / e + vertical beam size using X-ray synchrotron radiation, and will eventually have the capability for single-shot (single bunch, single turn) measurements. The preparation of a deep Si detector and high-speed readout electronics for single-shot measurements is underway. In the meantime for Phase 1 and 2, we used a scintillator screen and CCD camera for multi-bunch measurements. The XRM has been installed in each ring and images X-rays from a bending magnet that pass through optical elements (a single pinhole and coded apertures). Several studies (geometrical scale factors, emittance control knob, and beam lifetime study) were carried out during the commissioning. In Phase 1 (February–June 2016), the measured vertical emittances ε y are ∼ 10 pm for LER (consistent with the optical estimation) and ∼ 35 pm for HER (3.5 × greater than the optical estimation). Analysis of the beam size and lifetime measurements suggests unexpectedly large point spread functions (PSF), particularly in the HER. The spatial resolution of the imaging system (defect of focus, diffraction, and spherical aberration) and scattering in the beamline (EGS5 simulation) contribute ∼ 6 µm of PSF, which does not adequately account for the observed PSF. The Phase 2 commissioning commenced in May–July 2018, with thinner Be filters, new optical elements, scintillator, and CCD camera with the purpose to reduce the PSF in HER. The Phase 2 study results suggest the PSF σ s ∼ 6. 6 µm in HER (corresponding to the spatial resolution of the imaging system and scattering in the beamline), which is ∼ 5 × smaller than in Phase 1. The overall performances of XRMs in LER and HER are accurate. The XRM in LER will be able to measure the design beam size at the zero current (14 µm). For the HER, the PSF that we observed during the Phase 2 indicates that the minimum measured beam size corresponds to the emittance at the design current (12.9 pm) and the XRM will be able to measure the design beam size at the zero current (7 µm). [ABSTRACT FROM AUTHOR]

Published
2019
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9. SuperKEKB collider.

Author

Akai, Kazunori, Furukawa, Kazuro, and Koiso, Haruyo

Subjects
*COLLIDERS (Nuclear physics), *ELECTRONS, *POSITRONS, *COLLISIONS (Nuclear physics), *MAGNETS
Abstract

Abstract SuperKEKB, a 7 GeV electron – 4 GeV positron double-ring collider, is constructed by upgrading KEKB in order to seek new physics beyond the Standard Model. The design luminosity of SuperKEKB is 8 × 1 0 35 cm − 2 s − 1 —40 times higher than that achieved by KEKB. The greater part of the gain comes from significantly decreasing the beam sizes at the interaction point based on the nanobeam collision scheme; the design beam currents in both rings are double those achieved in KEKB. Large-scale construction to upgrade both the collider rings and the injector was conducted, and beam commissioning without the Belle II detector and final-focus magnets was successfully carried out from February to June in 2016. Subsequently, renovation of the interaction region, including the installation of the final-focus magnets and Belle II, and construction in the final stage of a new positron damping ring were conducted. Having completed the interaction region, beam collision tuning is scheduled from March till July in 2018. This paper reviews the design, construction, and beam commissioning of SuperKEKB. [ABSTRACT FROM AUTHOR]

Published
2018
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10. Detectors for extreme luminosity: Belle II.

Author

Adachi, I., Browder, T.E., Križan, P., Tanaka, S., and Ushiroda, Y.

Subjects
*DETECTORS, *LUMINOSITY, *NUCLEAR energy, *MESONS, *COLLISIONS (Nuclear physics)
Abstract

Abstract We describe the Belle II detector at the SuperKEKB electron–positron accelerator. SuperKEKB operates at the energy of the ϒ (4 S) resonance where pairs of B mesons are produced in a coherent quantum mechanical state with no additional particles. Belle II, the first Super B factory detector, aims to achieve performance comparable to the original Belle and BaBar B factory experiments, which first measured the large CP violating effects in the B meson system, with much higher luminosity collisions and larger beam-induced backgrounds. [ABSTRACT FROM AUTHOR]

Published
2018
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11. A neural network for beam background decomposition in Belle II at SuperKEKB.

Author

Schwenker, B., Herzberg, L., Buch, Y., Frey, A., Natochii, A., Vahsen, S., and Nakayama, H.

Subjects
*TIME series analysis, *NONLINEAR regression
Abstract

We describe a neural network for predicting the background hit rate in the Belle II detector produced by the SuperKEKB electron–positron collider. The neural network, BGNet, learns to predict the individual contributions of different physical background sources, such as beam-gas scattering or continuous top-up injections into the collider, to Belle II sub-detector rates. The samples for learning are archived 1 Hz time series of diagnostic variables from the SuperKEKB collider subsystems and measured hit rates of Belle II used as regression targets. We test the learned model by predicting detector hit rates on archived data from different run periods not used during training. We show that a feature attribution method can help interpret the source of changes in the background level over time. [ABSTRACT FROM AUTHOR]

Published
2023
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12. Vibration and luminosity frequency analysis of the SuperKEKB collider

Author

Maurizio Serluca, Gael Balik, Laurent Brunetti, Benjamin Aimard, Agnes Dominjon, Philip Bambade, Sandry Wallon, Salvatore Di Carlo, Mika Masuzawa, Sadaharu Uehara, Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
oscillation: spectrum, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Ground motion, Lumibelle2, luminosity: spectrum, BELLE, SuperKEKB, Mechanical vibrations, 00-01, 01 natural sciences, 99-00, monitoring, KEK-B, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, Instrumentation, performance, mechanics
Abstract

International audience; The SuperKEKB collider has entered the physics production phase with the aim to reach its target luminosity of 6×1035 cm−2s−1. Vibrations of the accelerator elements, especially around the Interaction Point (IP), could limit the performance of the collider. Since 2018, a 24-hour monitoring system of vibrations has been put in place on both sides of the Belle II detector. Measurements and analyses of the spectral components of these vibrations and of the transfer function of the mechanical supports are presented, along with measurements of luminosity spectra from the LumiBelle2 detectors, showing good agreement in spectral peak frequencies for several of the vibration sources.

Published
2022
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13. B-flavor tagging at Belle II

Author

Abudinén, F., Akopov, N., Bilka, T., Sandilya, S., Santelj, L., Sato, Y., Schwartz, A. J., Sevior, M. E., Soffer, A., Spataro, S., Stroili, R., Sutcliffe, W., Tagnani, D., Bilokin, S., Takizawa, M., Tamponi, U., Tenchini, F., Torassa, E., Urquijo, P., Vitale, L., Yusa, Y., Zani, L., Zhou, Q. D., Žlebčík, R., Biswas, D., Zupanc, A., Belle-II Collaboration, Bodrov, D., Borah, J., Bračko, M., Branchini, P., Budano, A., Campajola, M., Casarosa, G., Aloisio, A., Cecchi, C., Cheaib, R., Chekelian, V., Chen, C., Chen, Y. Q., Cho, H. -E., Cunliffe, S., De Nardo, G., De Pietro, G., de Sangro, R., Babu, Varghese, Dey, S., Di Canto, A., Di Capua, F., Dong, T. V., Dujany, G., Ecker, P., Eliachevitch, M., Ferber, T., Forti, F., Ganiev, E., Banerjee, Sw., Gaz, A., Gelb, M., Gemmler, J., Godang, R., Goldenzweig, P., Graziani, E., Hara, K., Hershenhorn, A., Higuchi, T., Hill, E. C., Bauer, M., Hohmann, M., Humair, T., Inguglia, G., Junkerkalefeld, H., Karl, R., Kato, Y., Keck, T., Kiesling, C., Kim, C. -H., Kohani, S., Bennett, J. V., Komarov, I., Kraetzschmar, T. M. G., Križan, P., Krohn, J. F., Kuhr, T., Kumar, J., Kumara, K., Kurz, S., Lacaprara, S., La Licata, C., Bernlochner, F. U., Laurenza, M., Lautenbach, K., Lee, S. C., Lieret, K., Gioi, L. Li, Liu, Q. Y., Longo, S., Maggiora, M., Manoni, E., Marinas, C., Bessner, M., Martini, A., Meier, F., Merola, M., Metzner, F., Milesi, M., Miyabayashi, K., Mohanty, G. B., Mueller, F., Murphy, C., Oxford, E. R., Bettarini, S., Park, S. -H., Passeri, A., Pham, F., Piilonen, L. E., Pokharel, S., Prim, M. T., Pulvermacher, C., Rados, P., Ritter, M., Rostomyan, A., Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Belle-II, Abudinen, F., Akopov, N., Aloisio, A., Babu, V., Banerjee, S., Bauer, M., Bennett, J. V., Bernlochner, F. U., Bessner, M., Bettarini, S., Bilka, T., Bilokin, S., Biswas, D., Bodrov, D., Borah, J., Bracko, M., Branchini, P., Budano, A., Campajola, M., Casarosa, G., Cecchi, C., Cheaib, R., Chekelian, V., Chen, C., Chen, Y. Q., Cho, H. -E., Cunliffe, S., De Nardo, G., De Pietro, G., de Sangro, R., Dey, S., Canto, A. D., Capua, F. D., Dong, T. V., Dujany, G., Ecker, P., Eliachevitch, M., Ferber, T., Forti, F., Ganiev, E., Gaz, A., Gelb, M., Gemmler, J., Godang, R., Goldenzweig, P., Graziani, E., Hara, K., Hershenhorn, A., Higuchi, T., Hill, E. C., Hohmann, M., Humair, T., Inguglia, G., Junkerkalefeld, H., Karl, R., Kato, Y., Keck, T., Kiesling, C., Kim, C. -H., Kohani, S., Komarov, I., Kraetzschmar, T. M. G., Krizan, P., Krohn, J. F., Kuhr, T., Kumar, J., Kumara, K., Kurz, S., Lacaprara, S., La Licata, C., Laurenza, M., Lautenbach, K., Lee, S. C., Lieret, K., Gioi, L. L., Liu, Q. Y., Longo, S., Maggiora, M., Manoni, E., Marinas, C., Martini, A., Meier, F., Merola, M., Metzner, F., Milesi, M., Miyabayashi, K., Mohanty, G. B., Mueller, F., Murphy, C., Oxford, E. R., Park, S. -H., Passeri, A., Pham, F., Piilonen, L. E., Pokharel, S., Prim, M. T., Pulvermacher, C., Rados, P., Ritter, M., Rostomyan, A., Sandilya, S., Santelj, L., Sato, Y., Schwartz, A. J., Sevior, M. E., Soffer, A., Spataro, S., Stroili, R., Sutcliffe, W., Tagnani, D., Takizawa, M., Tamponi, U., Tenchini, F., Torassa, E., Urquijo, P., Vitale, L., Yusa, Y., Zani, L., Zhou, Q. D., Zlebcik, R., Zupanc, A., Abudin??n, F., Banerjee, Sw., Bra??ko, M., Di Canto, A., Di Capua, F., Kri??an, P., Li Gioi, L., and leb????k, R.

Subjects
Upsilon(10570): electroproduction, Physics and Astronomy (miscellaneous), particle identification: efficiency, High Energy Physics::Lattice, FOS: Physical sciences, BELLE, annihilation [electron positron], B meson, Bottom mesons, electron positron: annihilation, CP [asymmetry], violation [CP], High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), particle identification: performance, KEK-B, decay modes [B0], CP: violation, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Belle II, ddc:530, Engineering (miscellaneous), efficiency [particle identification], Physics, High Energy Physics::Phenomenology, B0 anti-B0: mixing, Bottom meson, B-flavor tagging, SuperKEKB, electron positron: colliding beams, asymmetry: CP, CKM matrix, performance [particle identification], electroproduction [Upsilon(10570)], semileptonic decay [anti-B0], colliding beams [electron positron], High Energy Physics::Experiment, B0: decay modes, mixing [B0 anti-B0], anti-B0: semileptonic decay, experimental results
Abstract

The European physical journal / C 82(4), 283 (2022). doi:10.1140/epjc/s10052-022-10180-9, We report on new flavor tagging algorithms developed to determine the quark-flavor content of bottom ( [inline-graphic not available: see fulltext]) mesons at Belle II. The algorithms provide essential inputs for measurements of quark-flavor mixing and charge-parity violation. We validate and evaluate the performance of the algorithms using hadronic [inline-graphic not available: see fulltext] decays with flavor-specific final states reconstructed in a data set corresponding to an integrated luminosity of 62.8 fb$^{-1}$, collected at the resonance with the Belle II detector at the SuperKEKB collider. We measure the total effective tagging efficiency to be $\begin{aligned} \varepsilon _\mathrm{eff} = \big (30.0 \pm 1.2(\text {stat}) \pm 0.4(\text {syst})\big )\% \end{aligned}$for a category-based algorithm and $\begin{aligned} \varepsilon _\mathrm{eff} = \big (28.8 \pm 1.2(\text {stat}) \pm 0.4(\text {syst})\big )\% \end{aligned}$for a deep-learning-based algorithm., Published by Springer, Heidelberg

Published
2022
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14. Development of a compact HTS lead unit for the SC correction coils of the SuperKEKB final focusing magnet system.

Author

Zong, Zhanguo, Ohuchi, Norihito, Tsuchiya, Kiyosumi, and Arimoto, Yasushi

Subjects
*SUPERCONDUCTING coils, *CRYOSTATS, *HIGH temperature superconductors, *LIQUID helium, *MAGNETS, *ELECTRIC currents
Abstract

Forty-three superconducting (SC) correction coils with maximum currents of about 60 A are installed in the SuperKEKB final focusing magnet system. Current leads to energize the SC correction coils should have an affordable heat load and fit the spatial constraints in the service cryostat where the current leads are installed. To address the requirements, design optimization of individual lead was performed with vapor cooled current lead made of a brass material, and a compact unit was designed to accommodate eight current leads together in order to be installed with one port in the service cryostat. The 2nd generation high temperature SC (HTS) tape was adopted and soldered at the cold end of the brass current lead to form a hybrid HTS lead structure. A prototype of the compact lead unit with HTS tape was constructed and tested with liquid helium (LHe) environment. This paper presents a cryogenic measurement system to simulate the real operation conditions in the service cryostat, and analysis of the experimental results. The measured results showed excellent agreement with the theoretical analysis and numerical simulation. In total, 11 sets of the compact HTS lead units were constructed for the 43 SC correction coils at KEK. One set from the mass production was tested in cryogenic conditions, and exhibited the same performance as the prototype. The compact HTS lead unit can feed currents to four SC correction coils simultaneously with the simple requirement of controlling and monitoring helium vapor flow, and has a heat load of about 0.762 L/h in terms of LHe consumption. [ABSTRACT FROM AUTHOR]

Published
2016
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15. A Neural Network approach to reconstructing SuperKEKB beam parameters from beamstrahlung.

Author

Di Carlo, S., Bonvicini, G., Althubiti, N.A., Ayad, R., De La Cruz-Burelo, E., Domínguez, I., El Bashir, B.O., Farhat, H., Flanagan, J., Gillard, R., Gamez, S. Izaguirre, Kanazawa, K., Kumara, K., Liventsev, D., Podesta-Lerma, P.L.M., Ricalde-Herrmann, D., Perez, D. Rodriguez, Tejeda-Muñoz, G., Tobiyama, M., and de la Cruz, I. Heredia

Subjects
*MACHINE learning, *ANGLES
Abstract

This work shows how it is possible to reconstruct SuperKEKB's beam parameters using a Neural Network with beamstrahlung signal from the Large Angle Beamstrahlung Monitor (LABM) as input. We describe the device, the model, and discuss the results. [ABSTRACT FROM AUTHOR]

Published
2022
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16. Measurements of beam backgrounds in SuperKEKB Phase 2.

Author

Liptak, Z., Paladino, A., Santelj, L., Schueler, J., Stefkova, S., Tanigawa, H., Tsuzuki, N., Aloisio, A., Ahlburg, P., Bambade, P., Bassi, G., Barrett, M., Baudot, J., Browder, T.E., Casarosa, G., Cautero, G., Cinabro, D., Claus, G., Cuesta, D., and Di Capua, F.

Subjects
*VERTEX detectors, *POSITRONS, *DETECTORS
Abstract

The high design luminosity of the SuperKEKB electron–positron collider will result in challenging levels of beam-induced backgrounds in the interaction region. Understanding and mitigating these backgrounds is critical to the success of the Belle II experiment. We report on the first background measurements performed after roll-in of the Belle II detector, a period known as SuperKEKB Phase 2, utilizing both the BEAST II system of dedicated background detectors and the Belle II detector itself. We also report on first revisions to the background simulation made in response to our findings. Backgrounds measured include contributions from synchrotron radiation, beam-gas, Touschek, and injection backgrounds. At the end of Phase 2, single-beam backgrounds originating from the 4 GeV positron Low Energy Ring (LER) agree reasonably well with simulation, while backgrounds from the 7 GeV electron High Energy Ring (HER) are approximately one order of magnitude higher than simulation. We extrapolate these backgrounds forward and conclude it is safe to install the Belle II vertex detector. [ABSTRACT FROM AUTHOR]

Published
2022
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17. Search for B^{+}→K^{+}νν[over ¯] Decays Using an Inclusive Tagging Method at Belle II

Author

Abudinén, F, Adachi, I, Adamczyk, K, Ahlburg, P, Aihara, H, Akopov, N, Aloisio, A, Anh Ky, N, Asner, D M, Atmacan, H, Aushev, T, Aushev, V, Baur, A, Babu, V, Baehr, S, Bambade, P, Banerjee, Sw, Bansal, S, Baudot, J, Becker, J, Behera, P K, Bennett, J V, Bernieri, E, Bernlochner, F U, Bertemes, M, Bertholet, E, Bessner, M, Bettarini, S, Bianchi, F, Bilka, T, Biswas, D, Bozek, A, Bračko, M, Branchini, P, Braun, N, Browder, T E, Budano, A, Bussino, S, Campajola, M, Cao, L, Casarosa, G, Cecchi, C, Červenkov, D, Chang, P, Cheaib, R, Chekelian, V, Chen, C, Chen, Y-T, Cheon, B G, Chilikin, K, Chirapatpimol, K, Cho, K, Cho, S-J, Choudhury, S, Cinabro, D, Corona, L, Cremaldi, L M, Cunliffe, S, Czank, T, Dattola, F, De La Cruz-Burelo, E, de Marino, G, De Nardo, G, De Nuccio, M, De Pietro, G, de Sangro, R, Destefanis, M, Dey, S, De Yta-Hernandez, A, Di Canto, A, Di Capua, F, Dingfelder, J, Doležal, Z, Domínguez Jiménez, I, Dong, T V, Dort, K, Dubey, S, Duell, S, Dujany, G, Eidelman, S, Eliachevitch, M, Epifanov, D, Ferber, T, Ferlewicz, D, Fillinger, T, Finocchiaro, G, Fiore, S, Fodor, A, Forti, F, Frey, A, Fulsom, B G, Gabyshev, N, Ganiev, E, Garcia-Hernandez, M, Garmash, A, Gaur, V, Gaz, A, Gellrich, A, Giordano, R, Giri, A, Glazov, A, Gobbo, B, Godang, R, Goldenzweig, P, Golob, B, Grace, P, Gradl, W, Graziani, E, Greenwald, D, Guan, Y, Gudkova, K, Hadjivasiliou, C, Halder, S, Hara, K, Hartbrich, O, Hayasaka, K, Hayashii, H, Hazra, S, Hearty, C, Heredia de la Cruz, I, Hernández Villanueva, M, Hershenhorn, A, Higuchi, T, Hill, E C, Hirata, H, Hoek, M, Hohmann, M, Hsu, C-L, Humair, T, Iijima, T, Inami, K, Inguglia, G, Irakkathil Jabbar, J, Ishikawa, A, Itoh, R, Iwasaki, M, Iwasaki, Y, Jackson, P, Jacobs, W W, Jaffe, D E, Jin, Y, Joo, C, Junkerkalefeld, H, Kaliyar, A B, Kandra, J, Kang, K H, Karl, R, Karyan, G, Kawasaki, T, Ketter, C, Kichimi, H, Kiesling, C, Kim, C-H, Kim, D Y, Kim, Y-K, Kimmel, T D, Kodyš, P, Koga, T, Kohani, S, Konno, T, Korobov, A, Korpar, S, Kovalenko, E, Kraetzschmar, T M G, Krinner, F, Križan, P, Krokovny, P, Kuhr, T, Kumar, J, Kumar, M, Kumar, R, Kumara, K, Kunigo, T, Kurz, S, Kuzmin, A, Kwon, Y-J, Lacaprara, S, Lai, Y-T, La Licata, C, Lanceri, L, Lange, J S, Laurenza, M, Lautenbach, K, Le Diberder, F R, Lee, S C, Leitl, P, Levit, D, Lewis, P M, Li, C, Li, L K, Li, S X, Li, Y B, Libby, J, Lieret, K, Liptak, Z, Liu, Q Y, Liventsev, D, Longo, S, Lozar, A, Lueck, T, Lyu, C, Maggiora, M, Maity, S, Manfredi, R, Manoni, E, Marcello, S, Marinas, C, Martini, A, Masuda, M, Matsuda, T, Matsuoka, K, Matvienko, D, Meier, F, Merola, M, Metzner, F, Milesi, M, Miller, C, Miyabayashi, K, Miyake, H, Mizuk, R, Mohanty, G B, Moser, H-G, Mrvar, M, Müller, F J, Murphy, C, Mussa, R, Nakamura, K R, Nakao, M, Natkaniec, Z, Natochii, A, Nayak, M, Nazaryan, G, Niebuhr, C, Nisar, N K, Nishida, S, Nishimura, K, Ogawa, S, Onishchuk, Y, Ono, H, Onuki, Y, Oskin, P, Ozaki, H, Pakhlov, P, Pakhlova, G, Paladino, A, Pang, T, Panta, A, Paoloni, E, Pardi, S, Park, H, Park, S-H, Paschen, B, Passeri, A, Pathak, A, Patra, S, Paul, S, Pedlar, T K, Peruzzi, I, Pestotnik, R, Piccolo, M, Piilonen, L E, Podesta-Lerma, P L M, Podobnik, T, Pokharel, S, Polat, G, Popov, V, Praz, C, Prell, S, Prencipe, E, Prim, M T, Rad, N, Rados, P, Raiz, S, Remnev, M, Ripp-Baudot, I, Ritter, M, Rizzo, G, Rizzuto, L B, Robertson, S H, Rodríguez Pérez, D, Roney, J M, Rostomyan, A, Rout, N, Russo, G, Sahoo, D, Sanders, D A, Sandilya, S, Sangal, A, Santelj, L, Sato, Y, Savinov, V, Scavino, B, Schueler, J, Schwanda, C, Schwartz, A J, Seddon, R M, Seino, Y, Selce, A, Senyo, K, Serrano, J, Sevior, M E, Sfienti, C, Shiu, J-G, Shwartz, B, Sibidanov, A, Simon, F, Sobie, R J, Soffer, A, Sokolov, A, Solovieva, E, Spataro, S, Spruck, B, Starič, M, Stefkova, S, Stottler, Z S, Stroili, R, Sumihama, M, Sumisawa, K, Summers, D J, Sutcliffe, W, Suzuki, S Y, Svidras, H, Tabata, M, Takahashi, M, Takizawa, M, Tamponi, U, Tanaka, S, Tanida, K, Tanigawa, H, Taniguchi, N, Taras, P, Tenchini, F, Tonelli, D, Torassa, E, Toutounji, N, Trabelsi, K, Uchida, M, Unno, Y, Uno, K, Uno, S, Urquijo, P, Ushiroda, Y, Usov, Y V, Vahsen, S E, van Tonder, R, Varner, G S, Varvell, K E, Vinokurova, A, Vitale, L, Wach, B, Waheed, E, Wakeling, H M, Wan Abdullah, W, Wang, M-Z, Wang, X L, Warburton, A, Watanuki, S, Webb, J, Welsch, M, Wessel, C, Wiechczynski, J, Windel, H, Xu, X P, Yabsley, B D, Yamada, S, Yan, W, Yang, S B, Ye, H, Yelton, J, Yin, J H, Yook, Y M, Yoshihara, K, Yuan, C Z, Yusa, Y, Zani, L, Zhilich, V, Zhou, Q D, Zhou, X Y, Zhukova, V I, Abudinén, F, Adachi, I, Adamczyk, K, Ahlburg, P, Aihara, H, Akopov, N, Aloisio, A, Anh Ky, N, Asner, D M, Atmacan, H, Aushev, T, Aushev, V, Baur, A, Babu, V, Baehr, S, Bambade, P, Banerjee, Sw, Bansal, S, Baudot, J, Becker, J, Behera, P K, Bennett, J V, Bernieri, E, Bernlochner, F U, Bertemes, M, Bertholet, E, Bessner, M, Bettarini, S, Bianchi, F, Bilka, T, Biswas, D, Bozek, A, Bračko, M, Branchini, P, Braun, N, Browder, T E, Budano, A, Bussino, S, Campajola, M, Cao, L, Casarosa, G, Cecchi, C, Červenkov, D, Chang, P, Cheaib, R, Chekelian, V, Chen, C, Chen, Y-T, Cheon, B G, Chilikin, K, Chirapatpimol, K, Cho, K, Cho, S-J, Choudhury, S, Cinabro, D, Corona, L, Cremaldi, L M, Cunliffe, S, Czank, T, Dattola, F, De La Cruz-Burelo, E, de Marino, G, De Nardo, G, De Nuccio, M, De Pietro, G, de Sangro, R, Destefanis, M, Dey, S, De Yta-Hernandez, A, Di Canto, A, Di Capua, F, Dingfelder, J, Doležal, Z, Domínguez Jiménez, I, Dong, T V, Dort, K, Dubey, S, Duell, S, Dujany, G, Eidelman, S, Eliachevitch, M, Epifanov, D, Ferber, T, Ferlewicz, D, Fillinger, T, Finocchiaro, G, Fiore, S, Fodor, A, Forti, F, Frey, A, Fulsom, B G, Gabyshev, N, Ganiev, E, Garcia-Hernandez, M, Garmash, A, Gaur, V, Gaz, A, Gellrich, A, Giordano, R, Giri, A, Glazov, A, Gobbo, B, Godang, R, Goldenzweig, P, Golob, B, Grace, P, Gradl, W, Graziani, E, Greenwald, D, Guan, Y, Gudkova, K, Hadjivasiliou, C, Halder, S, Hara, K, Hartbrich, O, Hayasaka, K, Hayashii, H, Hazra, S, Hearty, C, Heredia de la Cruz, I, Hernández Villanueva, M, Hershenhorn, A, Higuchi, T, Hill, E C, Hirata, H, Hoek, M, Hohmann, M, Hsu, C-L, Humair, T, Iijima, T, Inami, K, Inguglia, G, Irakkathil Jabbar, J, Ishikawa, A, Itoh, R, Iwasaki, M, Iwasaki, Y, Jackson, P, Jacobs, W W, Jaffe, D E, Jin, Y, Joo, C, Junkerkalefeld, H, Kaliyar, A B, Kandra, J, Kang, K H, Karl, R, Karyan, G, Kawasaki, T, Ketter, C, Kichimi, H, Kiesling, C, Kim, C-H, Kim, D Y, Kim, Y-K, Kimmel, T D, Kodyš, P, Koga, T, Kohani, S, Konno, T, Korobov, A, Korpar, S, Kovalenko, E, Kraetzschmar, T M G, Krinner, F, Križan, P, Krokovny, P, Kuhr, T, Kumar, J, Kumar, M, Kumar, R, Kumara, K, Kunigo, T, Kurz, S, Kuzmin, A, Kwon, Y-J, Lacaprara, S, Lai, Y-T, La Licata, C, Lanceri, L, Lange, J S, Laurenza, M, Lautenbach, K, Le Diberder, F R, Lee, S C, Leitl, P, Levit, D, Lewis, P M, Li, C, Li, L K, Li, S X, Li, Y B, Libby, J, Lieret, K, Liptak, Z, Liu, Q Y, Liventsev, D, Longo, S, Lozar, A, Lueck, T, Lyu, C, Maggiora, M, Maity, S, Manfredi, R, Manoni, E, Marcello, S, Marinas, C, Martini, A, Masuda, M, Matsuda, T, Matsuoka, K, Matvienko, D, Meier, F, Merola, M, Metzner, F, Milesi, M, Miller, C, Miyabayashi, K, Miyake, H, Mizuk, R, Mohanty, G B, Moser, H-G, Mrvar, M, Müller, F J, Murphy, C, Mussa, R, Nakamura, K R, Nakao, M, Natkaniec, Z, Natochii, A, Nayak, M, Nazaryan, G, Niebuhr, C, Nisar, N K, Nishida, S, Nishimura, K, Ogawa, S, Onishchuk, Y, Ono, H, Onuki, Y, Oskin, P, Ozaki, H, Pakhlov, P, Pakhlova, G, Paladino, A, Pang, T, Panta, A, Paoloni, E, Pardi, S, Park, H, Park, S-H, Paschen, B, Passeri, A, Pathak, A, Patra, S, Paul, S, Pedlar, T K, Peruzzi, I, Pestotnik, R, Piccolo, M, Piilonen, L E, Podesta-Lerma, P L M, Podobnik, T, Pokharel, S, Polat, G, Popov, V, Praz, C, Prell, S, Prencipe, E, Prim, M T, Rad, N, Rados, P, Raiz, S, Remnev, M, Ripp-Baudot, I, Ritter, M, Rizzo, G, Rizzuto, L B, Robertson, S H, Rodríguez Pérez, D, Roney, J M, Rostomyan, A, Rout, N, Russo, G, Sahoo, D, Sanders, D A, Sandilya, S, Sangal, A, Santelj, L, Sato, Y, Savinov, V, Scavino, B, Schueler, J, Schwanda, C, Schwartz, A J, Seddon, R M, Seino, Y, Selce, A, Senyo, K, Serrano, J, Sevior, M E, Sfienti, C, Shiu, J-G, Shwartz, B, Sibidanov, A, Simon, F, Sobie, R J, Soffer, A, Sokolov, A, Solovieva, E, Spataro, S, Spruck, B, Starič, M, Stefkova, S, Stottler, Z S, Stroili, R, Sumihama, M, Sumisawa, K, Summers, D J, Sutcliffe, W, Suzuki, S Y, Svidras, H, Tabata, M, Takahashi, M, Takizawa, M, Tamponi, U, Tanaka, S, Tanida, K, Tanigawa, H, Taniguchi, N, Taras, P, Tenchini, F, Tonelli, D, Torassa, E, Toutounji, N, Trabelsi, K, Uchida, M, Unno, Y, Uno, K, Uno, S, Urquijo, P, Ushiroda, Y, Usov, Y V, Vahsen, S E, van Tonder, R, Varner, G S, Varvell, K E, Vinokurova, A, Vitale, L, Wach, B, Waheed, E, Wakeling, H M, Wan Abdullah, W, Wang, M-Z, Wang, X L, Warburton, A, Watanuki, S, Webb, J, Welsch, M, Wessel, C, Wiechczynski, J, Windel, H, Xu, X P, Yabsley, B D, Yamada, S, Yan, W, Yang, S B, Ye, H, Yelton, J, Yin, J H, Yook, Y M, Yoshihara, K, Yuan, C Z, Yusa, Y, Zani, L, Zhilich, V, Zhou, Q D, Zhou, X Y, and Zhukova, V I

Subjects
flavor-changing neutral-current decay, Bottom meson, Belle II, SuperKEKB, B meson, Bottom mesons, inclusive tagging
Abstract

A search for the flavor-changing neutral-current decay B^{+}→K^{+}νν[over ¯] is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63 fb^{-1} collected at the ϒ(4S) resonance and a sample of 9 fb^{-1} collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B^{+}→K^{+}νν[over ¯] decay, but also the inclusive properties of the other B meson in the ϒ(4S)→BB[over ¯] event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B^{+}→K^{+}νν[over ¯] of 4.1×10^{-5} is set at the 90% confidence level.

Published
2021

18. A z-Vertex Trigger for Belle II.

Author

Skambraks, S., Abudinen, F., Chen, Y., Feindt, M., Fruhwirth, R., Heck, M., Kiesling, C., Knoll, A., Neuhaus, S., Paul, S., and Schieck, J.

Subjects
*DRIFT chambers, *ARTIFICIAL neural networks, *THREE-dimensional display systems, *MULTIVARIATE analysis, *ELECTRIC noise
Abstract

The Belle II experiment will go into operation at the upgraded SuperKEKB collider in 2016. SuperKEKB is designed to deliver an instantaneous luminosity \cal L = 8 \times 10^35~\cm^ - 2~\s^ - 1. The experiment will therefore have to cope with a much larger machine background than its predecessor Belle, in particular from events outside of the interaction region. We present the concept of a track trigger, based on a neural network approach, that is able to suppress a large fraction of this background by reconstructing the z (longitudinal) position of the event vertex within the latency of the first level trigger. The trigger uses the hit information from the Central Drift Chamber (CDC) of Belle II within narrow cones in polar and azimuthal angle as well as in transverse momentum (“sectors”), and estimates the z-vertex without explicit track reconstruction. The preprocessing for the track trigger is based on the track information provided by the standard CDC trigger. It takes input from the 2D track finder, adds information from the stereo wires of the CDC, and finds the appropriate sectors in the CDC for each track. Within the sector, the z-vertex is estimated by a specialized neural network, with the drift times from the CDC as input and a continuous output corresponding to the scaled z-vertex. The neural algorithm will be implemented in programmable hardware. To this end a Virtex 7 FPGA board will be used, which provides at present the most promising solution for a fully parallelized implementation of neural networks or alternative multivariate methods. A high speed interface for external memory will be integrated into the platform, to be able to store the \cal O(10^9) parameters required. The contribution presents the results of our feasibility studies and discusses the details of the envisaged hardware solution. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
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19. Belle II and SuperKEKB.

Author

Križan, Peter

Subjects
HIGGS bosons, RADIOACTIVE decay, STANDARD model (Nuclear physics), QUANTUM theory, FERMIONS, NUCLEAR physics
Published
2013

20. Precise measurement of the $D^0$ and $D^+$ lifetimes at Belle II

Author

Abudinén, F., Adachi, I., Atmacan, H., Fodor, A., Forti, F., Fulsom, B. G., Gabrielli, A., Gabyshev, N., Gaz, A., Gellrich, A., Giakoustidis, G., Giordano, R., Giri, A., Aushev, V., Glazov, A., Gobbo, B., Godang, R., Goldenzweig, P., Golob, B., Gradl, W., Graziani, E., Greenwald, D., Gu, T., Guan, Y., Babu, V., Gudkova, K., Guilliams, J., Hadjivasiliou, C., Halder, S., Hara, K., Hara, T., Hartbrich, O., Hayasaka, K., Hayashii, H., Hazra, S., Bacher, S., Hearty, C., de la Cruz, I. Heredia, Villanueva, M. Hernández, Hershenhorn, A., Higuchi, T., Hill, E. C., Hirata, H., Hoek, M., Hohmann, M., Hsu, C.-L., Bae, H., Humair, T., Iijima, T., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, M., Iwasaki, Y., Jacobs, W. W., Jaffe, D. E., Baehr, S., Jang, E.-J., Jia, S., Jin, Y., Junkerkalefeld, H., Kakuno, H., Kaliyar, A. B., Kandra, J., Kang, K. H., Karl, R., Karyan, G., Bahinipati, S., Kato, Y., Kawasaki, T., Kiesling, C., Kim, C.-H., Kim, D. Y., Kim, Y.-K., Kim, Y., Kimmel, T. D., Kinoshita, K., Kodyš, P., Bambade, P., Koga, T., Kohani, S., Konno, T., Korpar, S., Kovalenko, E., Kowalewski, R., Kraetzschmar, T. M. G., Krinner, F., Križan, P., Krokovny, P., Banerjee, Sw., Kuhr, T., Kumar, J., Kumar, M., Kumar, R., Kumara, K., Kurz, S., Kuzmin, A., Kwon, Y.-J., Lacaprara, S., Lalwani, K., Bansal, S., Lam, T., Lanceri, L., Lange, J. S., Laurenza, M., Lautenbach, K., Le Diberder, F. R., Lee, S. C., Leitl, P., Levit, D., Li, C., Adamczyk, K., Barrett, M., Li, L. K., Libby, J., Lieret, K., Liptak, Z., Liu, Q. Y., Liventsev, D., Longo, S., Lueck, T., Lyu, C., Manfredi, R., Baudot, J., Manoni, E., Marinas, C., Martini, A., Matsuda, T., Matsuoka, K., Matvienko, D., McKenna, J. A., Meier, F., Merola, M., Metzner, F., Bauer, M., Miller, C., Miyabayashi, K., Mizuk, R., Mohanty, G. B., Molina-Gonzalez, N., Moon, H., Moser, H.-G., Mrvar, M., Murphy, C., Mussa, R., Baur, A., Nakamura, I., Nakamura, K. R., Nakao, M., Nakazawa, H., Natkaniec, Z., Natochii, A., Nazaryan, G., Niebuhr, C., Niiyama, M., Nisar, N. K., Becker, J., Nishida, S., Nishimura, K., Ogawa, S., Onishchuk, Y., Ono, H., Onuki, Y., Oskin, P., Oxford, E. R., Ozaki, H., Pakhlov, P., Behera, P. K., Paladino, A., Pang, T., Panta, A., Paoloni, E., Pardi, S., Park, H., Park, S.-H., Paschen, B., Passeri, A., Pathak, A., Bennett, J. V., Patra, S., Paul, S., Pedlar, T. K., Peruzzi, I., Peschke, R., Pestotnik, R., Pham, F., Piccolo, M., Piilonen, L. E., Angioni, G. Pinna, Bernieri, E., Podesta-Lerma, P. L. M., Podobnik, T., Pokharel, S., Polat, G., Popov, V., Praz, C., Prell, S., Prencipe, E., Prim, M. T., Purohit, M. V., Bernlochner, F. U., Purwar, H., Rad, N., Rados, P., Raiz, S., Reiter, S., Remnev, M., Ripp-Baudot, I., Rizzo, G., Rizzuto, L. B., Robertson, S. H., Bertemes, M., Roney, J. M., Rostomyan, A., Rout, N., Rozanska, M., Sahoo, D., Sanders, D. A., Sandilya, S., Sangal, A., Santelj, L., Sato, Y., Aggarwal, L., Bertholet, E., Savinov, V., Scavino, B., Schueler, J., Schwanda, C., Schwartz, A. J., Seino, Y., Selce, A., Senyo, K., Serrano, J., Sfienti, C., Bessner, M., Shiu, J.-G., Shwartz, B., Sibidanov, A., Simon, F., Sobie, R. J., Soffer, A., Sokolov, A., Solovieva, E., Spataro, S., Spruck, B., Bettarini, S., Starič, M., Stefkova, S., Stottler, Z. S., Stroili, R., Strube, J., Sumihama, M., Sutcliffe, W., Suzuki, S. Y., Svidras, H., Tabata, M., Bhardwaj, V., Takizawa, M., Tamponi, U., Tanaka, S., Tanida, K., Tanigawa, H., Taniguchi, N., Tenchini, F., Tiwary, R., Tonelli, D., Torassa, E., Bianchi, F., Toutounji, N., Trabelsi, K., Tsuboyama, T., Ueda, I., Uehara, S., Uematsu, Y., Uglov, T., Unger, K., Unno, Y., Uno, K., Bilka, T., Uno, S., Urquijo, P., Ushiroda, Y., Usov, Y. V., Vahsen, S. E., van Tonder, R., Varner, G. S., Vinokurova, A., Vitale, L., Vossen, A., Bilokin, S., Waheed, E., Wakeling, H. M., Wang, E., Wang, M.-Z., Wang, X. L., Warburton, A., Watanabe, M., Welsch, M., Wessel, C., Wiechczynski, J., Biswas, D., Won, E., Xu, X. P., Yabsley, B. D., Yamada, S., Yan, W., Yang, S. B., Ye, H., Yelton, J., Yin, J. H., Yoshihara, K., Bobrov, A., Yusa, Y., Zani, L., Zhilich, V., Zhou, Q. D., Zhou, X. Y., Zhukova, V. I., Žlebčík, R., Belle-II Collaboration, Bodrov, D., Ahmed, H., Bolz, A., Bozek, A., Bračko, M., Branchini, P., Braun, N., Briere, R. A., Browder, T. E., Budano, A., Bussino, S., Campajola, M., Aihara, H., Cao, L., Casarosa, G., Cecchi, C., Červenkov, D., Chang, M.-C., Chang, P., Cheaib, R., Chekelian, V., Chen, C., Chen, Y.-T., Akopov, N., Cheon, B. G., Chilikin, K., Chirapatpimol, K., Cho, H.-E., Cho, K., Cho, S.-J., Choi, S.-K., Choudhury, S., Cinabro, D., Corona, L., Aloisio, A., Cremaldi, L. M., Cunliffe, S., Czank, T., Dattola, F., De La Cruz-Burelo, E., de Marino, G., De Nardo, G., De Pietro, G., de Sangro, R., Destefanis, M., Ky, N. Anh, Dey, S., De Yta-Hernandez, A., Di Canto, A., Di Capua, F., Dingfelder, J., Doležal, Z., Jiménez, I. Domínguez, Dong, T. V., Dorigo, M., Dort, K., Asner, D. M., Dossett, D., Dubey, S., Duell, S., Dujany, G., Ecker, P., Epifanov, D., Ferber, T., Ferlewicz, D., Finocchiaro, G., Flood, K., Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Belle-II, Abudinén, F, Adachi, I, Adamczyk, K, Aggarwal, L, Ahmed, H, Aihara, H, Akopov, N, Aloisio, A, 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Trabelsi, K, Tsuboyama, T, Ueda, I, Uehara, S, Uematsu, Y, Uglov, T, Unger, K, Unno, Y, Uno, K, Uno, S, Urquijo, P, Ushiroda, Y, Usov, Y V, Vahsen, S E, van Tonder, R, Varner, G S, Vinokurova, A, Vitale, L, Vossen, A, Waheed, E, Wakeling, H M, Wang, E, Wang, M-Z, Wang, X L, Warburton, A, Watanabe, M, Welsch, M, Wessel, C, Wiechczynski, J, Won, E, Xu, X P, Yabsley, B D, Yamada, S, Yan, W, Yang, S B, Ye, H, Yelton, J, Yin, J H, Yoshihara, K, Yusa, Y, Zani, L, Zhilich, V, Zhou, Q D, Zhou, X Y, Zhukova, V I, Žlebčík, R, Abudinén, F., Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., Aloisio, A., Anh Ky, N., Asner, D. M., Atmacan, H., Aushev, V., Babu, V., Bacher, S., Bae, H., Baehr, S., Bahinipati, S., Bambade, P., Banerjee, Sw., Bansal, S., Barrett, M., Baudot, J., Bauer, M., Baur, A., Becker, J., Behera, P. K., Bennett, J. V., Bernieri, E., Bernlochner, F. U., Bertemes, M., Bertholet, E., Bessner, M., Bettarini, S., Bhardwaj, V., Bianchi, F., Bilka, T., Bilokin, S., Biswas, D., Bobrov, A., Bodrov, D., Bolz, A., Bozek, A., Bračko, M., Branchini, P., Braun, N., Briere, R. A., Browder, T. E., Budano, A., Bussino, S., Campajola, M., Cao, L., Casarosa, G., Cecchi, C., Červenkov, D., Chang, M. -C., Chang, P., Cheaib, R., Chekelian, V., Chen, C., Chen, Y. -T., Cheon, B. G., Chilikin, K., Chirapatpimol, K., Cho, H. -E., Cho, K., Cho, S. -J., Choi, S. -K., Choudhury, S., Cinabro, D., Corona, L., Cremaldi, L. M., Cunliffe, S., Czank, T., Dattola, F., De La Cruz-Burelo, E., de Marino, G., De Nardo, G., De Pietro, G., de Sangro, R., Destefanis, M., Dey, S., De Yta-Hernandez, A., Di Canto, A., Di Capua, F., Dingfelder, J., Doležal, Z., Domínguez Jiménez, I., Dong, T. V., Dorigo, M., Dort, K., Dossett, D., Dubey, S., Duell, S., Dujany, G., Ecker, P., Epifanov, D., Ferber, T., Ferlewicz, D., Finocchiaro, G., Flood, K., Fodor, A., Forti, F., Fulsom, B. G., Gabrielli, A., Gabyshev, N., Gaz, A., Gellrich, A., Giakoustidis, G., Giordano, R., Giri, A., Glazov, A., Gobbo, B., Godang, R., Goldenzweig, P., Golob, B., Gradl, W., Graziani, E., Greenwald, D., Gu, T., Guan, Y., Gudkova, K., Guilliams, J., Hadjivasiliou, C., Halder, S., Hara, K., Hara, T., Hartbrich, O., Hayasaka, K., Hayashii, H., Hazra, S., Hearty, C., Heredia de la Cruz, I., Hernández Villanueva, M., Hershenhorn, A., Higuchi, T., Hill, E. C., Hirata, H., Hoek, M., Hohmann, M., Hsu, C. -L., Humair, T., Iijima, T., Inami, K., Inguglia, G., Ishikawa, A., Itoh, R., Iwasaki, M., Iwasaki, Y., Jacobs, W. W., Jaffe, D. E., Jang, E. -J., Jia, S., Jin, Y., Junkerkalefeld, H., Kakuno, H., Kaliyar, A. B., Kandra, J., Kang, K. H., Karl, R., Karyan, G., Kato, Y., Kawasaki, T., Kiesling, C., Kim, C. -H., Kim, D. Y., Kim, Y. -K., Kim, Y., Kimmel, T. D., Kinoshita, K., Kodyš, P., Koga, T., Kohani, S., Konno, T., Korpar, S., Kovalenko, E., Kowalewski, R., Kraetzschmar, T. M. G., Krinner, F., Križan, P., Krokovny, P., Kuhr, T., Kumar, J., Kumar, M., Kumar, R., Kumara, K., Kurz, S., Kuzmin, A., Kwon, Y. -J., Lacaprara, S., Lalwani, K., Lam, T., Lanceri, L., Lange, J. S., Laurenza, M., Lautenbach, K., Le Diberder, F. R., Lee, S. C., Leitl, P., Levit, D., Li, C., Li, L. K., Libby, J., Lieret, K., Liptak, Z., Liu, Q. 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V., Purwar, H., Rad, N., Rados, P., Raiz, S., Reiter, S., Remnev, M., Ripp-Baudot, I., Rizzo, G., Rizzuto, L. B., Robertson, S. H., Roney, J. M., Rostomyan, A., Rout, N., Rozanska, M., Sahoo, D., Sanders, D. A., Sandilya, S., Sangal, A., Santelj, L., Sato, Y., Savinov, V., Scavino, B., Schueler, J., Schwanda, C., Schwartz, A. J., Seino, Y., Selce, A., Senyo, K., Serrano, J., Sfienti, C., Shiu, J. -G., Shwartz, B., Sibidanov, A., Simon, F., Sobie, R. J., Soffer, A., Sokolov, A., Solovieva, E., Spataro, S., Spruck, B., Starič, M., Stefkova, S., Stottler, Z. S., Stroili, R., Strube, J., Sumihama, M., Sutcliffe, W., Suzuki, S. Y., Svidras, H., Tabata, M., Takizawa, M., Tamponi, U., Tanaka, S., Tanida, K., Tanigawa, H., Taniguchi, N., Tenchini, F., Tiwary, R., Tonelli, D., Torassa, E., Toutounji, N., Trabelsi, K., Tsuboyama, T., Ueda, I., Uehara, S., Uematsu, Y., Uglov, T., Unger, K., Unno, Y., Uno, K., Uno, S., Urquijo, P., Ushiroda, Y., Usov, Y. V., Vahsen, S. E., van Tonder, R., Varner, G. S., Vinokurova, A., Vitale, L., Vossen, A., Waheed, E., Wakeling, H. M., Wang, E., Wang, M. -Z., Wang, X. L., Warburton, A., Watanabe, M., Welsch, M., Wessel, C., Wiechczynski, J., Won, E., Xu, X. P., Yabsley, B. D., Yamada, S., Yan, W., Yang, S. B., Ye, H., Yelton, J., Yin, J. H., Yoshihara, K., Yusa, Y., Zani, L., Zhilich, V., Zhou, Q. D., Zhou, X. Y., Zhukova, V. I., Žlebčík, R., Abudinen, F., Banerjee, S., Bracko, M., Cervenkov, D., De Marino, G., De Sangro, R., Dolezal, Z., Dominguez Jimenez, I., Heredia De La Cruz, I., Hernandez Villanueva, M., Kodys, P., Krizan, P., Staric, M., Van Tonder, R., Zlebcik, R., and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
D+: lifetime, Charmed meson, pair production [charm], Charm meson, charm: pair production, width [D0], FOS: Physical sciences, BELLE, annihilation [electron positron], electron positron: annihilation, lifetime: measured, D0: hadronic decay, High Energy Physics - Experiment, lifetime [D+], High Energy Physics - Experiment (hep-ex), KEK-B, D0: width, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Belle II, D+: hadronic decay, ddc:530, SuperKEKB, +K-+pi%2B+pi%22">D+ --> K- pi+ pi, hadronic decay [D0], Physics, +K-+pi%2B%22">D0 --> K- pi+, electron positron: colliding beams, hadronic decay [D+], colliding beams [electron positron], measured [lifetime], experimental results
Abstract

Physical review letters 127(21), 211801 (1-9) (2021). doi:10.1103/PhysRevLett.127.211801, We report a measurement of the $D^0$ and $D^+$ lifetimes using $D^0$���$K^-��^+$ and $D^+$���$K^-��^+��^+$ decays reconstructed in $e^+e^-$��� $c\overline{c}$ data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy $e^+e^-$ collider. The data, collected at center-of-mass energies at or near the $��$(4S) resonance, correspond to an integrated luminosity of 72 fb$^{-1}$. The results, $��$($D^0$)=410.5��1.1(stat)��0.8(syst) fs and ��($D^+$)=1030.4��4.7(stat)��3.1(syst) fs, are the most precise to date and are consistent with previous determinations., Published by APS, College Park, Md.

Published
2021
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21. Measurements of Beam Backgrounds in SuperKEKB Phase 2

Author

Z. Liptak, A. Paladino, L. Santelj, J. Schueler, S. Stefkova, H. Tanigawa, N. Tsuzuki, A. Aloisio, P. Ahlburg, P. Bambade, G. Bassi, M. Barrett, J. Baudot, T.E. Browder, G. Casarosa, G. Cautero, D. Cinabro, G. Claus, D. Cuesta, F. Di Capua, S. Di Carlo, J. Flanagan, A. Frey, B.G. Fulsom, Y. Funakoshi, M. Gabriel, R. Giordano, D. Giuressi, M. Goffe, K. Hara, O. Hartbrich, M.T. Hedges, D. Heuchel, N. Iida, T. Ishibashi, K. Jaaskelainen, D. Jehanno, S. de Jong, T. Kraetzschmar, C. La Licata, L. Lanceri, P. Leitl, P.M. Lewis, C. Marinas, C. Miller, H. Moser, K.R. Nakamura, H. Nakayama, C. Niebuhr, Y. Onuki, C. Pang, B. Paschen, I. Ripp-Baudot, G. Rizzo, J.M. Roney, H. Schreeck, B. Schwenker, F. Simon, M. Specht, B. Spruck, Y. Soloviev, M. Szelezniak, S. Tanaka, S. Terui, G. Tortone, T. Tsuboyama, Y. Uematsu, S.E. Vahsen, L. Vitale, H. Windel, Liptak, Z., Paladino, A., Santelj, L., Schueler, J., Stefkova, S., Tanigawa, H., Tsuzuki, N., Aloisio, A., Ahlburg, P., Bambade, P., Bassi, G., Barrett, M., Baudot, J., Browder, T. E., Casarosa, G., Cautero, G., Cinabro, D., Claus, G., Cuesta, D., Di Capua, F., Di Carlo, S., Flanagan, J., Frey, A., Fulsom, B. G., Funakoshi, Y., Gabriel, M., Giordano, R., Giuressi, D., Goffe, M., Hara, K., Hartbrich, O., Hedges, M. T., Heuchel, D., Iida, N., Ishibashi, T., Jaaskelainen, K., Jehanno, D., de Jong, S., Kraetzschmar, T., La Licata, C., Lanceri, L., Leitl, P., Lewis, P. M., Marinas, C., Miller, C., Moser, H., Nakamura, K. R., Nakayama, H., Niebuhr, C., Onuki, Y., Pang, C., Paschen, B., Ripp-Baudot, I., Rizzo, G., Roney, J. M., Schreeck, H., Schwenker, B., Simon, F., Specht, M., Spruck, B., Soloviev, Y., Szelezniak, M., Tanaka, S., Terui, S., Tortone, G., Tsuboyama, T., Uematsu, Y., Vahsen, S. E., Vitale, L., and Windel, H.

Subjects
Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, FOS: Physical sciences, SuperKEKB, Instrumentation and Detectors (physics.ins-det), Accelerator background, High Energy Physics - Experiment, Beam background, High Energy Physics - Experiment (hep-ex), Belle II, Physics::Accelerator Physics, High Energy Physics::Experiment, Instrumentation
Abstract

The high design luminosity of the SuperKEKB electron-positron collider will result in challenging levels of beam-induced backgro\ unds in the interaction region. Understanding and mitigating these backgrounds is critical to the success of the Belle~II experi\ ment. We report on the first background measurements performed after roll-in of the Belle II detector, a period known as SuperKE\ KB Phase 2, utilizing both the BEAST II system of dedicated background detectors and the Belle II detector itself. We also repor\ t on first revisions to the background simulation made in response to our findings. Backgrounds measured include contributions f\ rom synchrotron radiation, beam-gas, Touschek, and injection backgrounds. At the end of Phase 2, single-beam backgrounds origina\ ting from the 4 GeV positron Low Energy Ring (LER) agree reasonably well with simulation, while backgrounds from the 7 GeV elect\ ron High Energy Ring (HER) are approximately one order of magnitude higher than simulation. We extrapolate these backgrounds for\ ward and conclude it is safe to install the Belle II vertex detector., Comment: 22 Pages, 33 figures

Published
2021
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22. Light meson spectroscopy from Dalitz plot analyses ηc decays to η0K + K − , η0π + π − , and ηπ + π − produced in two-photon interactions

Author

J. ???P. Lees, V. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. ???N. Brown, Yu. ???G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, R. Cheaib, C. Hearty, T. ???S. Mattison, J. ???A. McKenna, R. ???Y. So, V. ???E. Blinov, A. ???R. Buzykaev, V. ???P. Druzhinin, V. ???B. Golubev, E. ???A. Kozyrev, E. ???A. Kravchenko, A. ???P. Onuchin, S. ???I. Serednyakov, Yu. ???I. Skovpen, E. ???P. Solodov, K. ???Yu. Todyshev, A. ???J. Lankford, B. Dey, J. ???W. Gary, O. Long, A. ???M. Eisner, W. ???S. Lockman, W. Panduro Vazquez, D. ???S. Chao, C. ???H. Cheng, B. Echenard, K. ???T. Flood, D. ???G. Hitlin, J. Kim, Y. Li, D. ???X. Lin, T. ???S. Miyashita, P. Ongmongkolkul, J. Oyang, F. ???C. Porter, M. R??hrken, Z. Huard, B. ???T. Meadows, B. ???G. Pushpawela, M. ???D. Sokoloff, L. Sun, J. ???G. Smith, S. ???R. Wagner, D. Bernard, M. Verderi, D. Bettoni, C. Bozzi, R. Calabrese, G. Cibinetto, E. Fioravanti, I. Garzia, E. Luppi, V. Santoro, A. Calcaterra, R. de Sangro, G. Finocchiaro, S. Martellotti, P. Patteri, I. ???M. Peruzzi, M. Piccolo, M. Rotondo, A. Zallo, S. Passaggio, C. Patrignani, B. ???J. Shuve, H. ???M. Lacker, B. Bhuyan, U. Mallik, C. Chen, J. Cochran, S. Prell, A. ???V. Gritsan, N. Arnaud, M. Davier, F. Le Diberder, A. ???M. Lutz, G. Wormser, D. ???J. Lange, D. ???M. Wright, J. ???P. Coleman, E. Gabathuler, D. ???E. Hutchcroft, D. ???J. Payne, C. Touramanis, A. ???J. Bevan, F. Di Lodovico, R. Sacco, G. Cowan, Sw. Banerjee, C. ???L. Davis, A. ???G. Denig, W. Gradl, K. Griessinger, A. Hafner, K. ???R. Schubert, R. ???J. Barlow, G. ???D. Lafferty, R. Cenci, A. Jawahery, D. ???A. Roberts, R. Cowan, S. ???H. Robertson, R. ???M. Seddon, N. Neri, F. Palombo, L. Cremaldi, R. Godang, D. ???J. Summers, P. Taras, G. De Nardo, C. Sciacca, G. Raven, C. ???P. Jessop, J. ???M. LoSecco, K. Honscheid, R. Kass, A. Gaz, M. Margoni, M. Posocco, G. Simi, F. Simonetto, R. Stroili, S. Akar, E. Ben-Haim, M. Bomben, G. ???R. Bonneaud, G. Calderini, J. Chauveau, G. Marchiori, J. Ocariz, M. Biasini, E. Manoni, A. Rossi, G. Batignani, S. Bettarini, M. Carpinelli, G. Casarosa, M. Chrzaszcz, F. Forti, M. ???A. Giorgi, A. Lusiani, B. Oberhof, E. Paoloni, M. Rama, G. Rizzo, J. ???J. Walsh, L. Zani, A. ???J. ???S. Smith, F. Anulli, R. Faccini, F. Ferrarotto, F. Ferroni, A. Pilloni, G. Piredda, C. B??nger, S. Dittrich, O. Gr??nberg, M. He??, T. Leddig, C. Vo??, R. Waldi, T. Adye, F. ???F. Wilson, S. Emery, G. Vasseur, D. Aston, C. Cartaro, M. ???R. Convery, J. Dorfan, W. Dunwoodie, M. Ebert, R. ???C. Field, B. ???G. Fulsom, M. ???T. Graham, C. Hast, W. ???R. Innes, P. Kim, D. ???W. ???G. ???S. Leith, S. Luitz, D. ???B. MacFarlane, D. ???R. Muller, H. Neal, B. ???N. Ratcliff, A. Roodman, M. ???K. Sullivan, J. Va???vra, W. ???J. Wisniewski, M. ???V. Purohit, J. ???R. Wilson, A. Randle-Conde, S. ???J. Sekula, H. Ahmed, M. Bellis, P. ???R. Burchat, E. ???M. ???T. Puccio, M. ???S. Alam, J. ???A. Ernst, R. Gorodeisky, N. Guttman, D. ???R. Peimer, A. Soffer, S. ???M. Spanier, J. ???L. Ritchie, R. ???F. Schwitters, J. ???M. Izen, X. ???C. Lou, F. Bianchi, F. De Mori, A. Filippi, D. Gamba, L. Lanceri, L. Vitale, F. Martinez-Vidal, A. Oyanguren, J. Albert, A. Beaulieu, F. ???U. Bernlochner, G. ???J. King, R. Kowalewski, T. Lueck, I. ???M. Nugent, J. ???M. Roney, R. ???J. Sobie, N. Tasneem, T. ???J. Gershon, P. ???F. Harrison, T. ???E. Latham, R. Prepost, S. ???L. Wu, Lees, J. ???P., Poireau, V., Tisserand, V., Grauges, E., Palano, A., Eigen, G., Brown, D. ???N., Kolomensky, Yu. ???G., Fritsch, M., Koch, H., Schroeder, T., Cheaib, R., Hearty, C., Mattison, T. ???S., Mckenna, J. ???A., So, R. ???Y., Blinov, V. ???E., Buzykaev, A. ???R., Druzhinin, V. ???P., Golubev, V. ???B., Kozyrev, E. ???A., Kravchenko, E. ???A., Onuchin, A. ???P., Serednyakov, S. ???I., Skovpen, Yu. ???I., Solodov, E. ???P., Todyshev, K. ???Yu., Lankford, A. ???J., Dey, B., Gary, J. ???W., Long, O., Eisner, A. ???M., Lockman, W. ???S., Panduro Vazquez, W., Chao, D. ???S., Cheng, C. ???H., Echenard, B., Flood, K. ???T., Hitlin, D. ???G., Kim, J., Li, Y., Lin, D. ???X., Miyashita, T. ???S., Ongmongkolkul, P., Oyang, J., Porter, F. ???C., R??hrken, M., Huard, Z., Meadows, B. ???T., Pushpawela, B. ???G., Sokoloff, M. ???D., Sun, L., Smith, J. ???G., Wagner, S. ???R., Bernard, D., Verderi, M., Bettoni, D., Bozzi, C., Calabrese, R., Cibinetto, G., Fioravanti, E., Garzia, I., Luppi, E., Santoro, V., Calcaterra, A., de Sangro, R., Finocchiaro, G., Martellotti, S., Patteri, P., Peruzzi, I. ???M., Piccolo, M., Rotondo, M., Zallo, A., Passaggio, S., Patrignani, C., Shuve, B. ???J., Lacker, H. ???M., Bhuyan, B., Mallik, U., Chen, C., Cochran, J., Prell, S., Gritsan, A. ???V., Arnaud, N., Davier, M., Le Diberder, F., Lutz, A. ???M., Wormser, G., Lange, D. ???J., Wright, D. ???M., Coleman, J. ???P., Gabathuler, E., Hutchcroft, D. ???E., Payne, D. ???J., Touramanis, C., Bevan, A. ???J., Di Lodovico, F., Sacco, R., Cowan, G., Banerjee, Sw., Davis, C. ???L., Denig, A. ???G., Gradl, W., Griessinger, K., Hafner, A., Schubert, K. ???R., Barlow, R. ???J., Lafferty, G. ???D., Cenci, R., Jawahery, A., Roberts, D. ???A., Cowan, R., Robertson, S. ???H., Seddon, R. ???M., Neri, N., Palombo, F., Cremaldi, L., Godang, R., Summers, D. ???J., Taras, P., De Nardo, G., Sciacca, C., Raven, G., Jessop, C. ???P., Losecco, J. ???M., Honscheid, K., Kass, R., Gaz, A., Margoni, M., Posocco, M., Simi, G., Simonetto, F., Stroili, R., Akar, S., Ben-Haim, E., Bomben, M., Bonneaud, G. ???R., Calderini, G., Chauveau, J., Marchiori, G., Ocariz, J., Biasini, M., Manoni, E., Rossi, A., Batignani, G., Bettarini, S., Carpinelli, M., Casarosa, G., Chrzaszcz, M., Forti, F., Giorgi, M. ???A., Lusiani, A., Oberhof, B., Paoloni, E., Rama, M., Rizzo, G., Walsh, J. ???J., Zani, L., Smith, A. ???J. ???S., Anulli, F., Faccini, R., Ferrarotto, F., Ferroni, F., Pilloni, A., Piredda, G., B??nger, C., Dittrich, S., Gr??nberg, O., He??, M., Leddig, T., Vo??, C., Waldi, R., Adye, T., Wilson, F. ???F., Emery, S., Vasseur, G., Aston, D., Cartaro, C., Convery, M. ???R., Dorfan, J., Dunwoodie, W., Ebert, M., Field, R. ???C., Fulsom, B. ???G., Graham, M. ???T., Hast, C., Innes, W. ???R., Kim, P., Leith, D. ???W. ???G. ???S., Luitz, S., Macfarlane, D. ???B., Muller, D. ???R., Neal, H., Ratcliff, B. ???N., Roodman, A., Sullivan, M. ???K., Va???vra, J., Wisniewski, W. ???J., Purohit, M. ???V., Wilson, J. ???R., Randle-Conde, A., Sekula, S. ???J., Ahmed, H., Bellis, M., Burchat, P. ???R., Puccio, E. ???M. ???T., Alam, M. ???S., Ernst, J. ???A., Gorodeisky, R., Guttman, N., Peimer, D. ???R., Soffer, A., Spanier, S. ???M., Ritchie, J. ???L., Schwitters, R. ???F., Izen, J. ???M., Lou, X. ???C., Bianchi, F., De Mori, F., Filippi, A., Gamba, D., Lanceri, L., Vitale, L., Martinez-Vidal, F., Oyanguren, A., Albert, J., Beaulieu, A., Bernlochner, F. ???U., King, G. ???J., Kowalewski, R., Lueck, T., Nugent, I. ???M., Roney, J. ???M., Sobie, R. ???J., Tasneem, N., Gershon, T. ???J., Harrison, P. ???F., Latham, T. ???E., Prepost, R., and Wu, S. ???L.

Subjects
Belle II, SuperKEKB, Dalitz, Dalitz plot analyses, light meson, Light meson spectroscopy, Dalitz plot analyse
Abstract

We study the processes γγ → ηc → η0KþK−, η0πþπ−, and ηπþπ− using a data sample of 519 fb−1 recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e+e− collider at center-of-mass energies at and near the Υ(nS) (n = 2, 3, 4) resonances. This is the first observation of the decay ηc → η0KþK− and we measure the branching fraction Γðηc → η0KþK−Þ=ðΓðηc → η0πþπ−Þ 1⁄4 0.644 0.039stat 0.032sys. Significant interference is observed between γγ → ηc → ηπþπ− and the nonresonant two-photon process γγ → ηπþπ−. A Dalitz plot analysis is performed of ηc decays to η0KþK−, η0πþπ−, and ηπþπ−. Combined with our previous analysis of ηc → KK ̄ π, we measure the K 0ð1430Þ parameters and the ratio between its η0K and πK couplings. The decay ηc → η0πþπ− is dominated by the f0ð2100Þ resonance, also observed in J=ψ radiative decays. A new a0(1700)→ ηπ resonance is observed in the ηc → ηπþπ− channel. We also compare ηc decays to η and η0 final states in association with scalar mesons as they relate to the identification of the scalar glueball.

Published
2021

24. DCDB and SWITCHERB, the readout ASICS for belle II DEPFET pixel detector.

Author

Peric, Ivan, Fischer, Peter, Knopf, Jochen, and Nguyen, Thi Hong Hanh

Abstract

DEPFET pixel detector will be used in Belle II experiment at SuperKEKB B-factory. We have designed two ASICs that will be used for the readout of DEPFET modules: the high-voltage row-control chip - SWITCHERB and the multi-channel ADC chip - DCDB. Both chips will be explained and the results obtained with test-systems presented. [ABSTRACT FROM PUBLISHER]

Published
2011
Full Text
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25. Status of the Super B Factory Projects.

Author

de Sangro, Riccardo

Subjects
*MESON factories, *ENGINEERING instruments, *LINEAR accelerators, *SCIENTIFIC apparatus & instruments, *PARTICLE accelerators
Abstract

Two proposals have been presented for the construction of super high luminosity B factories, the SuperB in Italy and SuperKEKB in Japan. We review the physics case for the construction of such facilities in the LHC era and highlight several topics of hadronic physics that can benefit from the high luminosity they will integrate. The present status of the accelerator and detector work toward the Technical Design Reports is also presented. [ABSTRACT FROM AUTHOR]

Published
2010
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26. CP Violation and the Future of Flavor Physics.

Author

Kiesling, Christian

Subjects
*MESON factories, *STANDARD model (Nuclear physics), *QUARKS, *MATRICES (Mathematics), *COLLIDERS (Nuclear physics)
Abstract

With the nearing completion of the first-generation experiments at asymmetric e+e- colliders running at the Υ(4S) resonance (“B-Factories”) a new era of high luminosity machines is at the horizon. We report here on the plans at KEK in Japan to upgrade the KEKB machine (“SuperKEKB”) with the goal of achieving an instantaneous luminosity exceeding 8×1035 cm-2 s-1, which is almost two orders of magnitude higher than KEKB. Together with the machine, the Belle detector will be upgraded as well (“Belle-II”), with significant improvements to increase its background tolerance as well as improving its physics performance. The new generation of experiments is scheduled to take first data in the year 2013. [ABSTRACT FROM AUTHOR]

Published
2009
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27. Študija meritve radiativnih razpadov mezonov B z detektorjem Belle II

Author

Cucek, Jernej and Golob, Boštjan

Subjects
simulacija Monte Carlo, Standard Model, New Physics, Nova Fizika, SuperKEKB, bottom mesons, radiativni pingvinski razpadi, mezoni s kvarkom $b$, Standardni Model, Cabibbo–Kobayashi–Maskawa matrix, ekskluzivna rekonstrukcija, exclusive reconstruction, Belle II, radiative penguin decays, matrika Cabibbo–Kobayashi–Maskawa, Monte Carlo simulation
Abstract

V magistrskem delu na simuliranem vzorcu podatkov detektorja Belle II opravimo študijo meritve razvejitvenih razmerij redkih radiativnih razpadov $B^{scriptscriptstyle 0}rightarrow rho^{scriptscriptstyle 0}gamma$ in $B^{scriptscriptstyle0}rightarrow K^{scriptscriptstyle *0}gamma$ ter od tu določimo razmerje elementov matrike CKM $|V_{scriptscriptstyle td}/V_{scriptscriptstyle ts}|$. Vzorec velikosti $375$ fb$^{-1}$ vsebuje simulirane podatke trkov elektronov in pozitronov pri veliki luminoznosti nadgrajenega trkalnika eksperimenta Belle II. Eksperiment bo tekom delovanja v naslednjih letih zbral vzorec velikosti $50$ ab$^{-1}$, kar pomeni 50-krat več razpadov mezonov $B$, kot jih je trenutno na voljo. Iz simuliranih podatkov najprej ekskluzivno rekonstruiramo oba izbrana radiativna razpada. Nato iz vzorca z uporabo pionskega veta in metod strojnega učenja izločimo čim več dogodkov ozadja. Iz kinematičnih porazdelitev določimo signalni donos obeh razpadov ter ocenimo učinkovitosti rekonstrukcij. Izkoristki rekonstrukcije imajo vrednosti $ epsilon_{scriptscriptstyle rho^{scriptscriptstyle 0}}=9% $ in $ epsilon_{scriptscriptstyle K^{scriptscriptstyle ast 0}}=22.7% $, ki so v primerjavi z dosedanjimi študijami na podatkih iz merjenega vzorca detektorja Belle višji. Iz signalnih donosov izračunane vrednosti razvejitvenih razmerij imajo vrednosti $mathcal{B}(B^{scriptscriptstyle 0}longrightarrowrho^{scriptscriptstyle 0} gamma)=(12pm3)cdot10^{-7}$ in $mathcal{B}(B^{scriptscriptstyle 0}longrightarrow K^{scriptscriptstyle ast0}gamma)=(4.19pm0.08)cdot10^{-5}$. Rezultati se v okviru statistične negotovosti ujemajo s teoretičnimi napovedmi in s svetovnim povprečjem za razpadni način $rho^{scriptscriptstyle 0}$ je relativna statistična negotovost primerljiva z rezultati študij izvedenih na meritvah detektorja Belle in znaša 26%, medtem ko je za razpadni način $K^{scriptscriptstyle ast 0}$ izboljšana in znaša 1.9%. Vrednost izračunanega razmerja elementov matrike CKM znaša $left|V_{scriptscriptstyle td}/V_{scriptscriptstyle ts}right|= 0.268pm 0.041$. Rezultati imajo glede na aktualno svetovno povprečje večjo statistično negotovost, h kateri prispevajo slabši rezultati razpadnega načina $rho^{scriptscriptstyle 0}$, vendar na podlagi naše študije ocenjujemo, da bo statistična negotovost na vzorcu, ki ustreza velikosti $50$ ab$^{-1}$, izboljšana za velikostni red. Negotovost razmerja $left|V_{scriptscriptstyle td}/V_{scriptscriptstyle ts}right|$ bo tako končno omejena predvsem z negotovostmi nekaterih parametrov potrebnih za izračun $left|V_{scriptscriptstyle td}/V_{scriptscriptstyle ts}right|$, ki so določeni teoretično ali iz drugih meritev. Using a simulated data sample of the Belle II detector measurements with an integrated luminosity of $375$ fb$^{-1}$ we performed a study of measurement of branching ratios for two rare $B$ meson radiative decays $B^{scriptscriptstyle 0}rightarrow rho^{scriptscriptstyle 0}gamma$ and $B^{scriptscriptstyle 0}rightarrow K^{scriptscriptstyle*0}gamma$. The obtained branching ratios were then used to determine the value of $lvert V_{scriptscriptstyle td}/V_{scriptscriptstyle ts} rvert$ ratio of the Cabibbo–Kobayashi–Maskawa matrix elements. The sample contained simulated data of electron-positron collisions from an upgraded high luminosity Belle II experiment, which will in its future operation period accumulate $50$ ab$^{-1}$ of data. From the data sample, we first performed na exclusive reconstruction of events for both decay chains. We proceeded with the elimination of background events with the usage of pion veto and machine learning techniques. We then obtained signal yields from fits to kinematic distributions of events and determined the reconstruction efficiencies, which were found to be $ epsilon_{scriptscriptstyle rho^{scriptscriptstyle 0}}=9% $ and $ epsilon_{scriptscriptstyle K^{scriptscriptstyle ast 0}}=22.7% $. In comparison to the results from older Belle studies, our reconstruction efficiencies are higher. The branching ratios determined from the signal yields have values of $mathcal{B}(B^{scriptscriptstyle 0}longrightarrowrho^{scriptscriptstyle 0} gamma)=(12pm3)cdot10^{-7}$ and $mathcal{B}(B^{scriptscriptstyle 0}longrightarrow K^{scriptscriptstyle ast0}gamma)=(4.19pm0.08)cdot10^{-5}$, and are within the statistical uncertainty in agreement with theoretical predictions and world average values in our case the relative statistical uncertainty for the $rho^{scriptscriptstyle 0}$ decay mode has a value of 26% and is comparable with results from older studies with Belle data, while the uncertainty of the $K^{scriptscriptstyle *0}$ mode branching ratio has a value of 1.9% and is improved in same comparison. Finally, we calculated the value of ratio CKM elements $left|V_{scriptscriptstyle td}/V_{scriptscriptstyle ts}right|= 0.268pm 0.041$ which is also in agreement with the world average values, albeit statistical uncertainty is larger descending from results obtained from $rho^{scriptscriptstyle 0}$ mode. Nevertheless, we estimate that the statistical uncertainty will be improved by an order of magnitude when the sample of size $50$ ab$^{-1}$ will be used. We conclude, that in the future, the uncertainty of the ratio $left|V_{scriptscriptstyle td}/V_{scriptscriptstyle ts}right|$ will be dominated by uncertainties of some of the parameters used to calculate the value of $left|V_{scriptscriptstyle td}/V_{scriptscriptstyle ts}right|$ that are calculated theoretically or determined from other measurements.

Published
2020

28. Search for new physics using radiative B meson decays and lifetime measurment of the B meson with the Belle II experiment

Author

Rasheed, Reem, Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, Jérôme Baudot, and STAR, ABES

Subjects
Asymétrie, [PHYS.PHYS]Physics [physics]/Physics [physics], Asymmetry, L’expérience Belle II, SuperKEKB, B meson, Collisionneur électron-positron, Electron-Positron Collisions, CP violation, Highest intensity, La violation de CP, SuperKEKB collider, Belle II, [PHYS.PHYS] Physics [physics]/Physics [physics], Méson B, Lifetime, La durée de vie, Le plus lumineux au monde
Abstract

After the Big Bang matter and antimatter were present in equal amounts. Today, however, everything we see, is made almost entirely of matter. A fundamental ingredient to explain this asymmetry between matter and antimatter is the violation of the CP (Charge Parity) symmetry. CP violation has been observed but quantitatively not enough to explain the huge asymmetry. The Belle II experiment in Japan studies the particles produced in electron-positron collisions at the SuperKEKB collider, the highest intensity collider in the World, allowing a high precision measurements of the known sources of CP violation and looking for new ones. In my PhD, I worked on measuring the CP violation in B meson radiative decays (decays with photon in final state) particularly promising thanks to their high sensitivity to possible new processes. Following this analysis, I started a new measurement of the B mesons lifetime where I could verify the robustness of the tools used in the CP violation measurement., Juste après le Big Bang, matière et antimatière étaient présentes en quantités égales. Mais l’univers que nous observons aujourd’hui est presque entièrement constitué de matière. Une différence de comportement des particules et anti-particules constitue un ingrédient fondamental pour expliquer cette disparition. La violation de la symétrie quantique CP (Charge et Parité) introduit une telle asymétrie, cependant le niveau observé actuellement pour cette violation ne suffit quantitativement pas. L’expérience Belle II vient de démarrer au Japon, elle permet d’étudier avec une très grande précision des systèmes particules/anti-particules produits par le collisionneur électron-positron SuperKEKB , qui sera bientôt le plus lumineux au monde. Dans mon doctorant, J'ai travaillé sur la mesure de la violation de CP dans les désintégrations radiatives du méson B (désintégrations avec des photons à l'état final) particulièrement prometteuses grâce à leur haute sensibilité aux possibles nouveaux processus. Suite à cette analyse, j'ai commencé une nouvelle mesure de la durée de vie des mésons B, pour vérifier la robustesse des outils utilisés pour mesurer la violation de CP.

Published
2020

29. Recherche de nouvelles physiques grâce à la désintégration radiative de mésons B et mesure de leur temps de vie avec l’expérience Belle II

Author

Rasheed, Reem, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, and Jérôme Baudot

Subjects
Asymétrie, [PHYS.PHYS]Physics [physics]/Physics [physics], Asymmetry, L’expérience Belle II, SuperKEKB, B meson, Collisionneur électron-positron, Electron-Positron Collisions, CP violation, Highest intensity, La violation de CP, SuperKEKB collider, Belle II, Méson B, Lifetime, La durée de vie, Le plus lumineux au monde
Abstract

After the Big Bang matter and antimatter were present in equal amounts. Today, however, everything we see, is made almost entirely of matter. A fundamental ingredient to explain this asymmetry between matter and antimatter is the violation of the CP (Charge Parity) symmetry. CP violation has been observed but quantitatively not enough to explain the huge asymmetry. The Belle II experiment in Japan studies the particles produced in electron-positron collisions at the SuperKEKB collider, the highest intensity collider in the World, allowing a high precision measurements of the known sources of CP violation and looking for new ones. In my PhD, I worked on measuring the CP violation in B meson radiative decays (decays with photon in final state) particularly promising thanks to their high sensitivity to possible new processes. Following this analysis, I started a new measurement of the B mesons lifetime where I could verify the robustness of the tools used in the CP violation measurement.; Juste après le Big Bang, matière et antimatière étaient présentes en quantités égales. Mais l’univers que nous observons aujourd’hui est presque entièrement constitué de matière. Une différence de comportement des particules et anti-particules constitue un ingrédient fondamental pour expliquer cette disparition. La violation de la symétrie quantique CP (Charge et Parité) introduit une telle asymétrie, cependant le niveau observé actuellement pour cette violation ne suffit quantitativement pas. L’expérience Belle II vient de démarrer au Japon, elle permet d’étudier avec une très grande précision des systèmes particules/anti-particules produits par le collisionneur électron-positron SuperKEKB , qui sera bientôt le plus lumineux au monde. Dans mon doctorant, J'ai travaillé sur la mesure de la violation de CP dans les désintégrations radiatives du méson B (désintégrations avec des photons à l'état final) particulièrement prometteuses grâce à leur haute sensibilité aux possibles nouveaux processus. Suite à cette analyse, j'ai commencé une nouvelle mesure de la durée de vie des mésons B, pour vérifier la robustesse des outils utilisés pour mesurer la violation de CP.

Published
2020

30. A NEW ERA OF FLAVOR PHYSICS: BELLE II AND THE SuperKEKB PROJECT.

Author

KIESLING, CHRISTIAN

Subjects
*PARTICLE physics, *CP violation, *SYMMETRY (Physics), *STANDARD model (Nuclear physics), *MESONS
Abstract

The physics of heavy flavors, including the search for new sources of CP symmetry violation and for rare decays of B mesons and τ leptons, is one of the pillars of modern particle physics in the quest for finding the inevitable extensions or modifications of the Standard Model. In this paper we first summarize the present status of CP violation as measured using the two pioneering B-Factories PEP II in the US and KEKB in Japan. Both machines have stopped operation (PEP II in 2008, KEKB end of June 2010), and full data samples from the BaBar and Belle experiments are now being analyzed for the "final word." The Standard Model of CP violation, based on the quark flavor mixing matrix as formulated by Kobayashi and Maskawa, shows overall consistency with the measurements. Still there are some tantalizing hints of possible deviations from the conventional wisdom. Strong arguments therefore exist to push for a new round of high-precision experiments, which will become available with the next generation of ultrahigh luminosity machines ("Super B-Factories"). We discuss the physics potential of such machines, aiming at integrated luminosities about two orders of magnitude larger than the present samples. We then report on the concrete plans at KEK in Japan to upgrade the KEKB machine ("SuperKEKB") with the goal of achieving an instantaneous luminosity exceeding 8 × 1035cm-2s-1, which is a factor of 40 larger than KEKB's world record. Together with the machine, the Belle detector will be upgraded as well ("Belle II"), with significant improvements to increase its background tolerance as well as improving its physics performance. The Belle II experiment is scheduled to see first collisions in 2015. [ABSTRACT FROM AUTHOR]

Published
2013
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31. Recent progress in sensor- and mechanics-R&D for the Belle II Silicon Vertex Detector.

Author

Bergauer, T., Doljeschi, P., Frankenberger, A., Friedl, M., Gfall, I., Irmler, C., Onuki, Y., Smiljic, D., Tsuboyama, T., and Valentan, M.

Subjects
*RESEARCH & development projects, *SILICON detectors, *COLLIDERS (Nuclear physics), *ELECTRON accelerators, *NUCLEAR physics experiments, *LUMINOSITY
Abstract

Abstract: The Belle experiment at the KEKB electron/positron collider in Tsukuba (Japan) was successfully running for more than ten years. A major update of the machine to SuperKEKB is now foreseen until 2015, aiming a peak luminosity which is 40 times the peak value of the previous system. This also requires a redesign of the Belle detector (leading to Belle II) and especially its Silicon Vertex Detector (SVD), which surrounds the beam pipe. The future Belle II SVD will consist of four layers of double-sided silicon strip sensors based on 6in. silicon wafers. Three of the four layers will be equipped with trapezoidal sensors in the slanted forward region. Moreover, two inner layers with pixel detectors based on DEPFET technology will complement the SVD as innermost detector. Since the KEKB-factory operates at relatively low energy, material inside the active volume has to be minimized in order to reduce multiple scattering. This can be achieved by arranging the sensors in the so-called “Origami chip-on-sensor concept”, and a very light-weight mechanical support structure made from carbon fiber reinforced Airex foam. Moreover, cooling for the front-end chips will ensure high efficiency at minimum material budget. In this paper, an overview of the future Belle II SVD design will be given, covering the silicon sensors, the readout electronics and the mechanics. A strong emphasis will be given to our R&D work on double-sided sensors where different p-stop layouts for the n-side of the detectors were compared. Moreover, this paper gives updated numbers for the mechanical dimensions of the ladders and their radii. [Copyright &y& Elsevier]

Published
2013
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32. Magnet System for the SuperKEKB Main Ring.

Author

Iinuma, Hiromi, Egawa, Kazumi, and Masuzawa, Mika

Subjects
*ACCELERATOR magnets, *LUMINOSITY, *STORAGE rings, *PARTICLE beams, *COLLIDERS (Nuclear physics)
Abstract

The next-generation B-factory “SuperKEKB” is now under construction. To achieve a 40-times higher luminosity than KEKB, which held the world's record luminosity of 2.1\times 10^34\ cm^-2s^-1, many items are being upgrade, and new challenges for the “nano-beam” scheme are being undertaken. In this paper, we introduce the major efforts of the magnet system in the main rings. [ABSTRACT FROM PUBLISHER]

Published
2012
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33. The Belle-II DEPFET pixel detector: A step forward in vertexing in the superKEKB flavour factory

Author

Marinas, C. and Vos, M.

Subjects
*PIXELS, *VERTEX detectors, *FLAVOR in particle physics, *FIELD-effect transistors, *SILICON, *PHYSICAL measurements
Abstract

Abstract: An upgrade of the successful asymmetric e+e− collider in KEK (Tsukuba, Japan) is foreseen by the fall of 2013. This new Super Flavor Factory will deliver an increased instantaneous luminosity of up to , 40 times larger than the current KEKB machine. To exploit these new conditions and provide high precision measurements of the decay vertex of the B meson systems, a new silicon vertex detector will be operated in Belle. This new detector will consist of two layers of DEPFET Active Pixel Sensors as close as possible to the interaction point. DEPFET is a field effect transistor, with an additional deep implant underneath the channel''s gate, integrated on a completely depleted bulk. This technology offers detection and an in-pixel amplification stage, while keeping low the power consumption. Under these conditions, thin sensors with small pixel size and low intrinsic noise are possible. In this article, an overview of the full system will be described, including the sensor, the front-end electronics and both the mechanical and thermal proposed solutions as well as the expected performance. [Copyright &y& Elsevier]

Published
2011
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34. Vibration and luminosity frequency analysis of the SuperKEKB collider.

Author

Serluca, Maurizio, Balik, Gael, Brunetti, Laurent, Aimard, Benjamin, Dominjon, Agnes, Bambade, Philip, Wallon, Sandry, Di Carlo, Salvatore, Masuzawa, Mika, and Uehara, Sadaharu

Subjects
*FREQUENCIES of oscillating systems, *VIBRATION (Mechanics), *TRANSFER functions, *LUMINOSITY, *DETECTORS
Abstract

The SuperKEKB collider has entered the physics production phase with the aim to reach its target luminosity of 6 × 1 0 35 cm − 2 s−1. Vibrations of the accelerator elements, especially around the Interaction Point (IP), could limit the performance of the collider. Since 2018, a 24-hour monitoring system of vibrations has been put in place on both sides of the Belle II detector. Measurements and analyses of the spectral components of these vibrations and of the transfer function of the mechanical supports are presented, along with measurements of luminosity spectra from the LumiBelle2 detectors, showing good agreement in spectral peak frequencies for several of the vibration sources. [ABSTRACT FROM AUTHOR]

Published
2022
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36. SuperKEKB beam final focus superconducting magnet system.

Author

Ohuchi, N., Arimoto, Y., Akai, K., Aoki, K., Higashi, N., Kanazawa, K., Kawai, M., Kawamoto, T., Koiso, H., Kondou, Y., Masuzawa, M., Morita, A., Nakamura, S., Ohnishi, Y., Ohsawa, Y., Oide, K., Okada, N., Oki, T., Sugimoto, H., and Tawada, M.

Subjects
*SUPERCONDUCTING magnets, *MAGNETS, *CRYOSTATS
Abstract

The SuperKEKB was designed and constructed as the upgraded accelerator of KEKB. In this accelerator design, the nano-beam scheme of collision was applied and a luminosity of 8 × 1035 cm−2s−1 was targeted. In the design, the beam final focus system was the key component in the accelerator hardware elements. This final focus system consists of 55 superconducting magnets. In this paper, the designs of the magnets, the cryostats and the cryogenic system are shown, and the field measurement results are reported. The SuperKEKB beam operation with the final focus system started on 2018 March 19, and the magnet quench events up to 2020 December 16 are described. [ABSTRACT FROM AUTHOR]

Published
2022
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37. Development of Event Building Farm for SuperKEKB.

Author

Itoh, Ko, Aihara, Hiroaki, Higuchi, Takeo, Itoh, Ryousuke, Iwasaki, Masako, Kakuno, Hidekazu, Nakao, Mikihiko, and Suzuki, Soh Yamagata

Subjects
*MESONS, *BETA decay, *PARTICLE accelerators, *DATA transmission systems, *PHYSICS experiments, *RADIOACTIVE decay, *PARTICLES (Nuclear physics), *NUCLEAR physics, *TESTING
Abstract

For the purpose of new physics search in rare B meson decays, an upgrade of the KEKB accelerator is being planned where the luminosity becomes more than ten times higher. The trigger rate with the increased luminosity is expected to reach up to 30 kHz with the event size of ∼300 kB. A new event builder is designed to cope with the condition by modularizing the system currently used in the Belle experiment and by operating multiple units in parallel. A test bench is built to study the new design and results of performance tests are reported. [ABSTRACT FROM AUTHOR]

Published
2006
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38. Fast luminosity monitoring and feedback using monocrystalline CVD diamond detectors at the SuperKEKB electron-positron collider in Japan

Author

Pang, Chengguo, Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris Saclay (COmUE), Philip Bambade, and STAR, ABES

Subjects
Diffusion Bhabha radiative, Dithering orbit feedback system, Monitorage rapide de la luminosité, Système d’asservissement de l’orbite par modulation et détection synchrone, [PHYS.PHYS.PHYS-INS-DET] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Radiative Bhabha scattering, [PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], [PHYS.PHYS.PHYS-ACC-PH] Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], Détecteur diamant sCVD, SuperKEKB, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Fast luminosity monitoring, sCVD diamond detectors
Abstract

SuperKEKB is at the foremost frontier of high luminosity e⁺e⁻ colliders, dedicated to the Belle-II experiment. It aims to provide an instantaneous luminosity of 8x10³⁵ by involving extremely tiny beams colliding at the Interaction Point (IP) based on the "nano-beam scheme". Therefore, excellent control of its beam orbit at the IP is required to ensure the optimum geometrical overlap between the two colliding beams, and thereby maximize the luminosity. Besides, effective instrumentation to diagnose the behavior of the beam at the IP and possible beam interactions between bunches along the train are also quite essential during the long and rather difficult process of machine tuning towards the nominal beam parameters. This thesis presents the development and application of a fast luminosity monitoring system based on sCVD diamond detectors at SuperKEKB, including: (1),train integrated luminosity signals every 1 ms which will be used as input to the dithering orbit feedback system, its relative precision is expected to be better than 1% when luminosity reaches 10³⁴ (2), sensitive train integrated luminosity signals over a large luminosity dynamic range every 1 s which will be sent to the SuperKEKB control room as immediate observable for machine collision tuning, and (3) bunch integrated luminosity signals every 1 s with sufficient relative precision to monitor the collision performance for each single bunch. To achieve such high relative precision and cover a large luminosity dynamic range, the radiative Bhabha process events at vanishing scattering angle will be measured, whose interaction cross-section is quite large and reasonably well known. The sCVD diamond detectors, which have fast signal formation and good radiation tolerance, were used to detect the charged particles in the secondary showers induced by the interaction between the lost Bhabha scattered particles and the beam pipe and specific radiator materials at carefully chosen locations downstream of the IP in both the LER and HER. A start-to-end simulation was performed on the dithering orbit feedback system using fast, precise luminosity signal as input, which includes: sCVD diamond detector signal estimation based on laboratory measurements with a radioactive source, signal sequence construction at SuperKEKB including single beam backgrounds and Bhabha scattered particles, luminosity signal procession, dithering orbit feedback simulation. It enabled verifying the feasibility of this system to maintain very high luminosity in the presence of ground motion, in particular it determined the relative precision of the fast luminosity signal every 1 ms. Besides, the radiation damage of the sCVD diamond detectors in the LER was also estimated based on a FLUKA simulation and applying the NIEL hypothesis. During the Phase-2 and early Phase-3 commissioning periods of SuperKEKB, our fast luminosity monitor based on sCVD diamond detectors was installed and operated successfully. Single beam loss processes, mainly Bremsstrahlung and Touschek, were studied in detail and compared with the simulation, showing good agreement. During the collision commissioning, train and bunch integrated luminosity signals every 1 s were provided for machine tuning. e.g. the vertical beam sizes were determined with the vertical offset scan technique based on our luminosity signals, both the average and for the individual bunches, which is very important and useful for the collision and IP local optics tuning during the long and rather difficult process of SuperKEKB machine tuning towards the nominal beam parameters. Besides, a train integrated luminosity signal every 1 ms with the expected relative precision was also provided and used as input to the dithering orbit feedback system for its first successful tests with deliberately introduced horizontal beam-beam offsets. More tests on the dithering orbit feedback system are expected to ensure its future continuous operation., Le collisionneur SuperKEKB, dédié à l'expérience Belle II, prévoit une très haute luminosité, inégalée à ce jour. Son objectif est de fournir une luminosité instantanée de 8x10³⁵ cm⁻²s⁻¹ en mettant en collision des faisceaux minuscules au point d'interaction (IP) sur la base du schéma "nano-beam". Par conséquent, un excellent contrôle de l'orbite du faisceau à l’IP est nécessaire pour assurer un recouvrement géométrique optimal entre les deux faisceaux en collision, et ainsi maximiser la luminosité. Dans ce cadre, cette thèse présente le développement et l'implémentation d'un système de monitoring rapide de la luminosité de SuperKEKB basé sur des détecteurs en diamant sCVD. Pour atteindre une précision relative aussi élevée et couvrir une gamme dynamique de luminosité élevée, le processus de diffusion Bhabha radiatif à très petit angle est utilisé, dont la section efficace d’interaction est très importante et relativement bien connue. Des détecteurs diamant sCVD, dont le signal est rapide et qui ont une bonne tolérance au rayonnement, sont utilisés pour détecter les particules chargées dans les gerbes électromagnétiques induites par l’interaction entre les particules Bhabha diffusées et perdues dans le tube à vide du faisceau, et dans les autres matériaux, en particulier un radiateur, à des emplacements choisis spécialement en aval de l'IP, dans les deux anneaux LER et HER. Une simulation de bout en bout du système d'asservissement de l'orbite du faisceau à l'IP basé sur notre signal de luminosité rapide et précis a été réalisé, qui comprend: une estimation du signal du détecteur de diamant sCVD, basé sur des mesures de laboratoire à l'aide d'une source radioactive, la construction de séquences de signal représentative de SuperKEKB comprenant les bruits de fond à un seul faisceau et les particules diffusées par le processus Bhabha, un traitement du signal de luminosité, et la simulation de l'asservissement de l'orbite. Il a été possible de vérifier la faisabilité de ce système pour maintenir la très haute luminosité de SuperKEKB en présence des mouvements du sol et a de déterminer la précision relative du signal de luminosité rapide qu'il est possible d'obtenir toutes les 1 ms. Au cours des phases de mise en service de SuperKEKB, la phase 2 et le début de la phase 3, notre moniteur de luminosité rapide basé sur des détecteurs en diamant sCVD a été installé et utilisé avec succès. Les processus de perte de faisceau, principalement ceux provenant des processus de Bremsstrahlung et de Touschek, ont été étudiés en détail et, par rapport à la simulation, un bon accord a été trouvé. Lors de la mise en service de la collision, des signaux de luminosité intégrés toutes les secondes étaient fournis en continu pour le réglage des paramètres des faisceaux à l'IP. En outre, un signal de luminosité intégré toutes les 1 ms avec la précision relative attendue a également été fourni et utilisé comme entrée du système d'asservissement de l'orbite à l'IP, notamment pour des premiers tests conduits avec succès avec des décalages de faisceau horizontaux introduits volontairement. Davantage de tests de ce système d'asservissement sont attendus pour assurer son bon fonctionnement en continu à l'avenir. Cette thèse présente le développement et l’application d’un système de surveillance rapide de la luminosité basé sur les détecteurs de sCVD diamant de SuperKEKB.

Published
2019

39. Monitorage rapide et asservissement de la luminosité du collisionneur électron-positron japonais SuperKEKB avec des capteurs diamant CVD monocristallins

Author

Pang, Chengguo, Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris Saclay (COmUE), and Philip Bambade

Subjects
Diffusion Bhabha radiative, Dithering orbit feedback system, Monitorage rapide de la luminosité, Système d’asservissement de l’orbite par modulation et détection synchrone, Radiative Bhabha scattering, [PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], Détecteur diamant sCVD, SuperKEKB, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Fast luminosity monitoring, sCVD diamond detectors
Abstract

SuperKEKB is at the foremost frontier of high luminosity e⁺e⁻ colliders, dedicated to the Belle-II experiment. It aims to provide an instantaneous luminosity of 8x10³⁵ by involving extremely tiny beams colliding at the Interaction Point (IP) based on the "nano-beam scheme". Therefore, excellent control of its beam orbit at the IP is required to ensure the optimum geometrical overlap between the two colliding beams, and thereby maximize the luminosity. Besides, effective instrumentation to diagnose the behavior of the beam at the IP and possible beam interactions between bunches along the train are also quite essential during the long and rather difficult process of machine tuning towards the nominal beam parameters. This thesis presents the development and application of a fast luminosity monitoring system based on sCVD diamond detectors at SuperKEKB, including: (1),train integrated luminosity signals every 1 ms which will be used as input to the dithering orbit feedback system, its relative precision is expected to be better than 1% when luminosity reaches 10³⁴ (2), sensitive train integrated luminosity signals over a large luminosity dynamic range every 1 s which will be sent to the SuperKEKB control room as immediate observable for machine collision tuning, and (3) bunch integrated luminosity signals every 1 s with sufficient relative precision to monitor the collision performance for each single bunch. To achieve such high relative precision and cover a large luminosity dynamic range, the radiative Bhabha process events at vanishing scattering angle will be measured, whose interaction cross-section is quite large and reasonably well known. The sCVD diamond detectors, which have fast signal formation and good radiation tolerance, were used to detect the charged particles in the secondary showers induced by the interaction between the lost Bhabha scattered particles and the beam pipe and specific radiator materials at carefully chosen locations downstream of the IP in both the LER and HER. A start-to-end simulation was performed on the dithering orbit feedback system using fast, precise luminosity signal as input, which includes: sCVD diamond detector signal estimation based on laboratory measurements with a radioactive source, signal sequence construction at SuperKEKB including single beam backgrounds and Bhabha scattered particles, luminosity signal procession, dithering orbit feedback simulation. It enabled verifying the feasibility of this system to maintain very high luminosity in the presence of ground motion, in particular it determined the relative precision of the fast luminosity signal every 1 ms. Besides, the radiation damage of the sCVD diamond detectors in the LER was also estimated based on a FLUKA simulation and applying the NIEL hypothesis. During the Phase-2 and early Phase-3 commissioning periods of SuperKEKB, our fast luminosity monitor based on sCVD diamond detectors was installed and operated successfully. Single beam loss processes, mainly Bremsstrahlung and Touschek, were studied in detail and compared with the simulation, showing good agreement. During the collision commissioning, train and bunch integrated luminosity signals every 1 s were provided for machine tuning. e.g. the vertical beam sizes were determined with the vertical offset scan technique based on our luminosity signals, both the average and for the individual bunches, which is very important and useful for the collision and IP local optics tuning during the long and rather difficult process of SuperKEKB machine tuning towards the nominal beam parameters. Besides, a train integrated luminosity signal every 1 ms with the expected relative precision was also provided and used as input to the dithering orbit feedback system for its first successful tests with deliberately introduced horizontal beam-beam offsets. More tests on the dithering orbit feedback system are expected to ensure its future continuous operation.; Le collisionneur SuperKEKB, dédié à l'expérience Belle II, prévoit une très haute luminosité, inégalée à ce jour. Son objectif est de fournir une luminosité instantanée de 8x10³⁵ cm⁻²s⁻¹ en mettant en collision des faisceaux minuscules au point d'interaction (IP) sur la base du schéma "nano-beam". Par conséquent, un excellent contrôle de l'orbite du faisceau à l’IP est nécessaire pour assurer un recouvrement géométrique optimal entre les deux faisceaux en collision, et ainsi maximiser la luminosité. Dans ce cadre, cette thèse présente le développement et l'implémentation d'un système de monitoring rapide de la luminosité de SuperKEKB basé sur des détecteurs en diamant sCVD. Pour atteindre une précision relative aussi élevée et couvrir une gamme dynamique de luminosité élevée, le processus de diffusion Bhabha radiatif à très petit angle est utilisé, dont la section efficace d’interaction est très importante et relativement bien connue. Des détecteurs diamant sCVD, dont le signal est rapide et qui ont une bonne tolérance au rayonnement, sont utilisés pour détecter les particules chargées dans les gerbes électromagnétiques induites par l’interaction entre les particules Bhabha diffusées et perdues dans le tube à vide du faisceau, et dans les autres matériaux, en particulier un radiateur, à des emplacements choisis spécialement en aval de l'IP, dans les deux anneaux LER et HER. Une simulation de bout en bout du système d'asservissement de l'orbite du faisceau à l'IP basé sur notre signal de luminosité rapide et précis a été réalisé, qui comprend: une estimation du signal du détecteur de diamant sCVD, basé sur des mesures de laboratoire à l'aide d'une source radioactive, la construction de séquences de signal représentative de SuperKEKB comprenant les bruits de fond à un seul faisceau et les particules diffusées par le processus Bhabha, un traitement du signal de luminosité, et la simulation de l'asservissement de l'orbite. Il a été possible de vérifier la faisabilité de ce système pour maintenir la très haute luminosité de SuperKEKB en présence des mouvements du sol et a de déterminer la précision relative du signal de luminosité rapide qu'il est possible d'obtenir toutes les 1 ms. Au cours des phases de mise en service de SuperKEKB, la phase 2 et le début de la phase 3, notre moniteur de luminosité rapide basé sur des détecteurs en diamant sCVD a été installé et utilisé avec succès. Les processus de perte de faisceau, principalement ceux provenant des processus de Bremsstrahlung et de Touschek, ont été étudiés en détail et, par rapport à la simulation, un bon accord a été trouvé. Lors de la mise en service de la collision, des signaux de luminosité intégrés toutes les secondes étaient fournis en continu pour le réglage des paramètres des faisceaux à l'IP. En outre, un signal de luminosité intégré toutes les 1 ms avec la précision relative attendue a également été fourni et utilisé comme entrée du système d'asservissement de l'orbite à l'IP, notamment pour des premiers tests conduits avec succès avec des décalages de faisceau horizontaux introduits volontairement. Davantage de tests de ce système d'asservissement sont attendus pour assurer son bon fonctionnement en continu à l'avenir. Cette thèse présente le développement et l’application d’un système de surveillance rapide de la luminosité basé sur les détecteurs de sCVD diamant de SuperKEKB.

Published
2019

40. High Energy K L Calibration at Belle II using Initial State Radiation

Author

Vaughan-Taylor, Lachlan

Subjects
Belle, Calibration, basf2, SuperKEKB, Kaon, ISR
Abstract

This thesis presents a feasibility study of a method for KL calibration at the Belle II experiment, using initial state radiation (ISR) production of the KS KL final state. By reconstructing the ISR photon, and the KS and subtracting their energy-momentum 4-vectors from that of the known e+ e − initial state, the 4-vector of the KL may be determined. Due to the loss of second order ISR photons and lost photon energy from incomplete electromagnetic shower reconstruction, a correction is applied to the photon energy. The expected efficiency, after all of the appropriate selections to isolate signal events were applied, was found to be of order 1%. This corresponds to roughly 100 well-reconstructed events per f b −1 of integrated luminosity produced at Belle II, with the difference between the MC generated and reconstructed KL energy found to be of the order of 5 MeV and with the angle between the truth and determined K L vector found to be of the order 0.02 radians=1.1◦. At this production rate, the currently available early Belle II data, which have an integrated luminosity of only 472pb−1, are likely not large enough for a meaningful KL calibration, however, Belle II is expected to produce 50ab−1 of integrated luminosity. As Belle II produces more data this method will become more and more feasible.

Published
2019

41. A fast luminosity monitor based on diamond detectors for the SuperKEKB collider

Author

S. Di Carlo, Mika Masuzawa, Y. Peinaud, Didier Jehanno, Sadaharu Uehara, Chengguo Pang, C. Rimbault, Philip Bambade, V. Kubytskyi, Yoshihiro Funakoshi, Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Nuclear and High Energy Physics, Offset (computer science), [PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], Radiative Bhabha, 01 natural sciences, luminosity: monitoring, Luminosity, Optics, KEK-B, electron positron: elastic scattering, 0103 physical sciences, Radiative transfer, Dither, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, Dithering feedback, Instrumentation, Diamond detector, detector: design, Physics, Interaction point, 010308 nuclear & particles physics, business.industry, SuperKEKB, sCVD diamond detector, Bunches, Physics::Accelerator Physics, Relative precision, business, beam: size, solid-state counter: diamond, Beam (structure), Beam instrumentation
Abstract

A fast luminosity monitor measuring the rate of the radiative Bhabha process at zero degree photon scattering angle based on diamond detectors was developed and successfully operated during the Phase-2 commissioning of SuperKEKB. The main purpose of this system, called LumiBelle2, is to provide: train integrated luminosity signals at 1 kHz with a relative precision better than 1% for luminosities higher than 1 0 34 c m − 2 s − 1 , input to a dithering feedback system designed to maintain an optimum horizontal overlap between the two colliding beams at the Interaction Point (IP), and bunch integrated luminosity signals at 1 Hz which are useful for machine tuning and beam parameters studies of the successive bunches along the train. In this paper, the design of the LumiBelle2 and Phase-2 results will be reported, including the evaluation of the single beam background, relative luminosity measurements and vertical beam size determinations at the IP using vertical offset scans.

Published
2019
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42. Beam Background at SuperKEKB During Phase 2 Operation

Author

Paladino, Antonio

Subjects
detector, background, superkekb, Physics::Accelerator Physics, kek, High Energy Physics::Experiment, IR and MDI, Accelerator Physics
Abstract

The SuperKEKB accelerator, the upgrade of the KEKB machine, will operate at an unprecedented instantaneous luminosity of 8x10³⁵/cm²/s¹, providing the Belle II experiment an expected integrated luminosity of about 50 inverse ab in ten years of operation. With the increased luminosity, the beam background is expected to grow significantly with respect to KEKB, leading, among other effects, to possible damage of detector components and suppression of signal events. We present studies done during the Phase 2 operation of SuperKEKB to evaluate the contribution of each background source, such as Touschek effect, beam-gas scattering, synchrotron radiation, and injection background. We also present studies performed on collimators and other solutions adopted to mitigate beam backgrounds in the interaction region., Proceedings of the 62th ICFA ABDW on High Luminosity Circular e$^+$e$^-$ Colliders, eeFACT2018, Hong Kong, China

Published
2019
Full Text
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43. The software library of the Belle II experiment

Author

Kim, Dorisyangsoo, Ritter, M., Bilka, T., Bobrov, A., Casarosa, G., Chilikin, K., Ferber, T., Godang, R., Jaegle, I., Kandra, J., Kodys, P., Kuhr, T., Kvasnicka, P., Nakayama, H., Piilonen, L., Pulvermacher, C., Santelj, L., Schwenker, B., Sibidanov, A., Soloviev, Y., Starič, M., and Uglov, T.

Subjects
Nuclear and High Energy Physics, Engineering, Particle physics, Real-time computing, Cloud computing, computer.software_genre, 01 natural sciences, KEKB, Software, framework, 0103 physical sciences, Belle II, Software system, 010306 general physics, computer.programming_language, software, 010308 nuclear & particles physics, business.industry, Software development, SuperKEKB, Python (programming language), simulation, B-factory, Operating system, User interface, business, computer
Abstract

A next generation B factory and the detector counterpart, SuperKEKB and Belle II, are being built in Japan, as the upgrades of KEKB and Belle, respectively. The new collider will start its commissioning in 2015. This is an ambitious project. The luminosity of the e + e - collider will be upgraded by a factor of 40, which will create a 50 times larger data set compared to the Belle sample. Both the background and the triggered event rates will be increased by a factor of at least 10. The Belle II software system is designed to accommodate these challenges and to run on grid, cloud, and local resources around the world. Various external software packages are employed to enhance the user interface. The software system, basf2 , is structured as a framework built with dynamic module loading and the ability of parallel processing. The system is written in C++ with Python steering scripts, compatible with common Linux operating systems. A full detector simulation library is created based on Geant4. In this paper, we will explain the design of the Belle II software structure and the current status of the software development.

Published
2016
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44. Search for Axionlike Particles Produced in e⁺e⁻ Collisions at Belle II

Author

Abudinén, F., Adachi, I., Aihara, H., Akopov, N., Aloisio, A., Ameli, F., Anh Ky, N., Asner, D. M., Aushev, T., Aushev, V., Babu, V., Baehr, S., Bahinipati, S., Bambade, P., Banerjee, Sw., Bansal, S., Baudot, J., Becker, J., Behera, P. K., Bennett, J. V., Bernieri, E., Bernlochner, F. U., Bertemes, M., Bessner, M., Bettarini, S., Bhardwaj, V., Bianchi, F., Bilka, T., Bilokin, S., Biswas, D., Bračko, M., Branchini, P., Braun, N., Browder, T. E., Budano, A., Bussino, S., Campajola, M., Casarosa, G., Cecchi, C., Cervenkov, D., Chang, M.-C., Chang, P., Cheaib, R., Chekelian, V., Cheon, B. G., Chilikin, K., Chirapatpimol, K., Cho, H.-E., Cho, K., Cho, S.-J., Choi, S.-K., Cinabro, D., Corona, L., Cremaldi, L. M., Cunliffe, S., Dash, N., Dattola, F., De La Cruz-Burelo, E., De Nardo, G., De Nuccio, M., De Pietro, G., De Sangro, R., Destefanis, M., De Yta-Hernandez, A., Di Capua, F., Doležal, Z., Dong, T. V., Dort, K., Dossett, D., Dujany, G., Eidelman, S., Ferber, T., Ferlewicz, D., Fiore, S., Fodor, A., Forti, F., Fulsom, B. G., Ganiev, E., Garg, R., Garmash, A., Gaur, V., Gaz, A., Gebauer, U., Gellrich, A., Gessler, T., Giordano, R., Giri, A., Gobbo, B., Godang, R., Goldenzweig, P., Golob, B., Gomis, P., Gradl, W., Graziani, E., Greenwald, D., Hadjivasiliou, C., Halder, S., Hartbrich, O., Hayasaka, K., Hayashii, H., Hearty, C., Hedges, M. T., Heredia De La Cruz, I., Villanueva, M. Hernández, Hershenhorn, A., Higuchi, T., Hill, E. C., Hirata, H., Hoek, M., Hohmann, M., Hsu, C.-L., Hu, Y., Inami, K., Inguglia, G., Irakkathil Jabbar, J., Ishikawa, A., Itoh, R., Jackson, P., Jacobs, W. W., Jaffe, D. E., Jang, E.-J., Jia, S., Jin, Y., Joo, C., Kaliyar, A. B., Kandra, J., Karyan, G., Kato, Y., Kichimi, H., Kiesling, C., Kim, C.-H., Kim, D. Y., Kim, H. J., Kim, S.-H., Kim, Y.-K., Kimmel, T. D., Kinoshita, K., Kleinwort, C., Kodyš, P., Koga, T., Kohani, S., Komarov, I., Korpar, S., Kraetzschmar, T. M. G., Križan, P., Krokovny, P., Kuhr, T., Kumar, M., Kumar, R., Kumara, K., Kurz, S., Kwon, Y.-J., Lacaprara, S., La Licata, C., Lanceri, L., Lange, J. S., Lee, I.-S., Lee, S. C., Leitl, P., Levit, D., Lewis, P. M., Li, C., Li, L. K., Li, Y. B., Libby, J., Lieret, K., Li Gioi, L., Liptak, Z., Liu, Q. Y., Liventsev, D., Longo, S., Luo, T., MacQueen, C., Maeda, Y., Manfredi, R., Manoni, E., Marcello, S., Marinas, C., Martini, A., Masuda, M., Matsuoka, K., Matvienko, D., Meggendorfer, F., Meier, F., Merola, M., Metzner, F., Milesi, M., Miller, C., Miyabayashi, K., Mizuk, R., Azmi, K., Mohanty, G. B., Moser, H.-G., Mrvar, M., Müller, F. J., Mussa, R., Nakamura, I., Nakao, M., Nakazawa, H., Natochii, A., Niebuhr, C., Nisar, N. K., Nishida, S., Nouxman, M. H. A., Ogawa, K., Ogawa, S., Ono, H., Oskin, P., Ozaki, H., Pakhlov, P., Paladino, A., Panta, A., Paoloni, E., Pardi, S., Park, H., Park, S.-H., Paschen, B., Passeri, A., Pathak, A., Patra, S., Paul, S., Pedlar, T. K., Peruzzi, I., Peschke, R., Piccolo, M., Piilonen, L. E., Polat, G., Popov, V., Praz, C., Prencipe, E., Prim, M. T., Purohit, M. V., Rad, N., Rados, P., Rasheed, R., Reif, M., Reiter, S., Remnev, M., Ripp-Baudot, I., Ritter, M., Ritzert, M., Rizzo, G., Robertson, S. H., Pérez, D. Rodríguez, Roney, J. M., Rosenfeld, C., Rostomyan, A., Rout, N., Sahoo, D., Sakai, Y., Sanders, D. A., Sandilya, S., Sangal, A., Santelj, L., Sato, Y., Savinov, V., Scavino, B., Schwanda, C., Schwartz, A. J., Seddon, R. M., Seino, Y., Selce, A., Senyo, K., Serrano, J., Sevior, M. E., Sfienti, C., Shiu, J.-G., Sibidanov, A., Simon, F., Sobie, R. J., Soffer, A., Solovieva, E., Spataro, S., Spruck, B., Starič, M., Stefkova, S., Stottler, Z. S., Stroili, R., Strube, J., Sumihama, M., Sumiyoshi, T., Summers, D. J., Sutcliffe, W., Svidras, H., Tabata, M., Takizawa, M., Tamponi, U., Tanaka, S., Tanida, K., Tanigawa, H., Taras, P., Tenchini, F., Tonelli, D., Torassa, E., Trabelsi, K., Uchida, M., Uglov, T., Unger, K., Unno, Y., Uno, S., Urquijo, P., Ushiroda, Y., Vahsen, S. E., Van Tonder, R., Varner, G. S., Varvell, K. E., Vinokurova, A., Vitale, L., Waheed, E., Wakai, M., Wakeling, H. M., Wang, C. H., Wang, M.-Z., Wang, X. L., Warburton, A., Watanabe, M., Watanuki, S., Webb, J., Wehle, S., Welsch, M., Wessel, C., Wiechczynski, J., Windel, H., Won, E., Wu, L. J., Xu, X. P., Yabsley, B., Yan, W., Yang, S. B., Ye, H., Yonenaga, M., Yuan, C. Z., Yusa, Y., Zani, L., Zhou, Q. D., Zhukova, V. I., Belle-II Collaboration, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Abudinén, F., Adachi, I., Aihara, H., Akopov, N., Aloisio, A., Ameli, F., Anh Ky, N., Asner, D. M., Aushev, T., Aushev, V., Babu, V., Baehr, S., Bahinipati, S., Bambade, P., Banerjee, Sw., Bansal, S., Baudot, J., Becker, J., Behera, P. K., Bennett, J. V., Bernieri, E., Bernlochner, F. U., Bertemes, M., Bessner, M., Bettarini, S., Bhardwaj, V., Bianchi, F., Bilka, T., Bilokin, S., Biswas, D., Bračko, M., Branchini, P., Braun, N., Browder, T. E., Budano, A., Bussino, S., Campajola, M., Casarosa, G., Cecchi, C., Červenkov, D., Chang, M. -C., Chang, P., Cheaib, R., Chekelian, V., Cheon, B. G., Chilikin, K., Chirapatpimol, K., Cho, H. -E., Cho, K., Cho, S. -J., Choi, S. -K., Cinabro, D., Corona, L., Cremaldi, L. M., Cunliffe, S., Dash, N., Dattola, F., De La Cruz-Burelo, E., De Nardo, G., De Nuccio, M., De Pietro, G., de Sangro, R., Destefanis, M., De Yta-Hernandez, A., Di Capua, F., Doležal, Z., Dong, T. V., Dort, K., Dossett, D., Dujany, G., Eidelman, S., Ferber, T., Ferlewicz, D., Fiore, S., Fodor, A., Forti, F., Fulsom, B. G., Ganiev, E., Garg, R., Garmash, A., Gaur, V., Gaz, A., Gebauer, U., Gellrich, A., Geßler, T., Giordano, R., Giri, A., Gobbo, B., Godang, R., Goldenzweig, P., Golob, B., Gomis, P., Gradl, W., Graziani, E., Greenwald, D., Hadjivasiliou, C., Halder, S., Hartbrich, O., Hayasaka, K., Hayashii, H., Hearty, C., Hedges, M. T., Heredia de la Cruz, I., Hernández Villanueva, M., Hershenhorn, A., Higuchi, T., Hill, E. C., Hirata, H., Hoek, M., Hohmann, M., Hsu, C. -L., Hu, Y., Inami, K., Inguglia, G., Irakkathil Jabbar, J., Ishikawa, A., Itoh, R., Jackson, P., Jacobs, W. W., Jaffe, D. E., Jang, E. -J., Jia, S., Jin, Y., Joo, C., Kaliyar, A. B., Kandra, J., Karyan, G., Kato, Y., Kichimi, H., Kiesling, C., Kim, C. -H., Kim, D. Y., Kim, H. J., Kim, S. -H., Kim, Y. -K., Kimmel, T. D., Kinoshita, K., Kleinwort, C., Kodyš, P., Koga, T., Kohani, S., Komarov, I., Korpar, S., Kraetzschmar, T. M. G., Križan, P., Krokovny, P., Kuhr, T., Kumar, M., Kumar, R., Kumara, K., Kurz, S., Kwon, Y. -J., Lacaprara, S., La Licata, C., Lanceri, L., Lange, J. S., Lee, I. -S., Lee, S. C., Leitl, P., Levit, D., Lewis, P. M., Li, C., Li, L. K., Li, Y. B., Libby, J., Lieret, K., Li Gioi, L., Liptak, Z., Liu, Q. Y., Liventsev, D., Longo, S., Luo, T., Macqueen, C., Maeda, Y., Manfredi, R., Manoni, E., Marcello, S., Marinas, C., Martini, A., Masuda, M., Matsuoka, K., Matvienko, D., Meggendorfer, F., Meier, F., Merola, M., Metzner, F., Milesi, M., Miller, C., Miyabayashi, K., Mizuk, R., Azmi, K., Mohanty, G. B., Moser, H. -G., Mrvar, M., Müller, F. J., Mussa, R., Nakamura, I., Nakao, M., Nakazawa, H., Natochii, A., Niebuhr, C., Nisar, N. K., Nishida, S., Nouxman, M. H. A., Ogawa, K., Ogawa, S., Ono, H., Oskin, P., Ozaki, H., Pakhlov, P., Paladino, A., Panta, A., Paoloni, E., Pardi, S., Park, H., Park, S. -H., Paschen, B., Passeri, A., Pathak, A., Patra, S., Paul, S., Pedlar, T. K., Peruzzi, I., Peschke, R., Piccolo, M., Piilonen, L. E., Polat, G., Popov, V., Praz, C., Prencipe, E., Prim, M. T., Purohit, M. V., Rad, N., Rados, P., Rasheed, R., Reif, M., Reiter, S., Remnev, M., Ripp-Baudot, I., Ritter, M., Ritzert, M., Rizzo, G., Robertson, S. H., Rodríguez Pérez, D., Roney, J. M., Rosenfeld, C., Rostomyan, A., Rout, N., Sahoo, D., Sakai, Y., Sanders, D. A., Sandilya, S., Sangal, A., Santelj, L., Sato, Y., Savinov, V., Scavino, B., Schwanda, C., Schwartz, A. J., Seddon, R. M., Seino, Y., Selce, A., Senyo, K., Serrano, J., Sevior, M. E., Sfienti, C., Shiu, J. -G., Sibidanov, A., Simon, F., Sobie, R. J., Soffer, A., Solovieva, E., Spataro, S., Spruck, B., Starič, M., Stefkova, S., Stottler, Z. S., Stroili, R., Strube, J., Sumihama, M., Sumiyoshi, T., Summers, D. J., Sutcliffe, W., Svidras, H., Tabata, M., Takizawa, M., Tamponi, U., Tanaka, S., Tanida, K., Tanigawa, H., Taras, P., Tenchini, F., Tonelli, D., Torassa, E., Trabelsi, K., Uchida, M., Uglov, T., Unger, K., Unno, Y., Uno, S., Urquijo, P., Ushiroda, Y., Vahsen, S. E., van Tonder, R., Varner, G. S., Varvell, K. E., Vinokurova, A., Vitale, L., Waheed, E., Wakai, M., Wakeling, H. M., Wang, C. H., Wang, M. -Z., Wang, X. L., Warburton, A., Watanabe, M., Watanuki, S., Webb, J., Wehle, S., Welsch, M., Wessel, C., Wiechczynski, J., Windel, H., Won, E., Wu, L. J., Xu, X. P., Yabsley, B., Yan, W., Yang, S. B., Ye, H., Yonenaga, M., Yuan, C. Z., Yusa, Y., Zani, L., Zhou, Q. D., Zhukova, V. I., Abudinen, F., Banerjee, S., Bracko, M., Cervenkov, D., De Sangro, R., Dolezal, Z., Gessler, T., Heredia De La Cruz, I., Hernandez Villanueva, M., Kodys, P., Krizan, P., Muller, F. J., Rodriguez Perez, D., Staric, M., and Van Tonder, R.

Subjects
pair production [photon], axionlike particles, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, BELLE, coupling constant: upper limit, annihilation [electron positron], electron positron: annihilation, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), KEK-B, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Belle II, ddc:530, direct production [axion], two-photon, gauge boson, axionlike particle, Physics, High Energy Physics::Phenomenology, pseudoscalar [interaction], photon, ALPs, coupling constant, axion: direct production, SuperKEKB, electron positron: colliding beams, Rare decays, upper limit [coupling constant], interaction: pseudoscalar, postulated particle, Rare decay, direct production, coupling: (axion 2photon), colliding beams [electron positron], ALP, axion-like particles, High Energy Physics::Experiment, photon: pair production, (axion 2photon) [coupling], experimental results
Abstract

Physical review letters 125(16), 161806 (2020). doi:10.1103/PhysRevLett.125.161806, We present a search for the direct production of a light pseudoscalar $a$ decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process ${e^+e^-\to\gamma a, a \to\gamma\gamma}$ in the mass range ${0.2} \,< m_a < {9.7}\,{\text{GeV/$c$}^2}$ using data corresponding to an integrated luminosity of $(445\pm 3)\,\text{pb}^{-1}$. Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axion-like particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling strength $g_{a\gamma\gamma}$ of ALPs to photons at the level of $10^{-3}\,{\text{GeV}^{-1}}$. The limits are the most restrictive to date for $0.2\, Published by Americal Physical Society, College Park, Md.

Published
2020
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45. Status of the super KEK B factory

Author

Bračko, Marko

Subjects
Physics::Instrumentation and Detectors, SuperBelle, mezoni B, Physics::Accelerator Physics, High Energy Physics::Experiment, udc:539.1, SuperKEKB, B mesons, B factories, tovarne mezonov B, KEKB
Abstract

We are preparing a major upgrade of the KEKB electron-positron collider, the Super KEK B factory (SuperKEKB) – a project that could detect new phenomena arising from physics beyond the Standard Model by using a large amount of data, corresponding to the integrated luminosity of 50 ab-1. This data set will allow studies of rare processes in B meson decays, D meson decays and τ lepton decays with an unprecedented sensitivity. To achieve the goal of this ambitious project, the design luminosity of the SuperKEKB is 8 mid 1035 cm-2s-1 – 50 times larger than that of the present KEKB collider. The current Belle detector will also be upgraded to take a full advantage of the high collider luminosity. The new detector, SuperBelle, is designed in such a way that it should perform at least as well as the present Belle spectrometer, despite the substantial increase in beam-induced backgrounds.

Published
2017

46. Performance studies of the Belle II Silicon Vertex Detector with data taken at the DESY test beam in April 2016

Author

Bosisio, Luciano, Lanceri, Livio, Vitale, Lorenzo, LA LICATA, Chiara, Fabrizio Palla and Francesco Forti (Chairpersons), Bosisio, Luciano, Lanceri, Livio, Vitale, Lorenzo, and LA LICATA, Chiara

Subjects
Belle II, SuperKEKB, SVD, vertex detector, solid state detector, semiconductor detector, performance
Abstract

Belle II is a multipurpose detector currently under construction and it will be operated at the next generation B-factory SuberKEKB in Japan. The main Belle II devices, devoted to the vertex reconstruction, are the Silicon Vertex Detector (SVD) and the Pixel Detector (PXD). In April 2016 a sector of the Belle II SVD and PXD has been tested in a beam of high energetic electrons at the test beam facility at DESY Hamburg (Germany). We report here the results for the hit efficiency estimation and the measurement of the resolution for the Belle II silicon vertex detector. Hit efficiencies are measured to be on average above 99.5% and the measured resolution is within the expectations.

Published
2017

47. The Belle II Experiment

Author

Kahn (On Behalf Of The Belle II Collaboration), James

Subjects
Belle II, SuperKEKB, B physics, Detectors and Experimental Techniques
Abstract

Set to begin data taking at the end of 2018, the Belle II experiment is the next-generation B-factory experiment hosted at KEK in Tsukuba, Japan. The experiment represents the cumulative effort from the collaboration of experimental and detector physics, computing, and software development. Taking everything learned from the previous Belle experiment, which ran from 1998 to 2010, Belle II aims to probe deeper than ever before into the field of heavy quark physics. By achieving an integrated luminosity of 50 ab−1 and accumulating 50 times more data than the previous experiment across its lifetime, along with a rewritten analysis framework, the Belle II experiment will push the high precision frontier of high energy physics. This paper will give an overview of the key components and development activities that make the Belle II experiment possible., CERN Proceedings, Vol 1 (2017): CERN-BINP Workshop for Young Scientists in e+e- Colliders

Published
2017

48. The Belle II SVD detector

Author

BOSISIO, LUCIANO, LANCERI, LIVIO, VITALE, LORENZO, LA LICATA, CHIARA, Fabrizio Palla and Francesco Forti (Chairpersons), Bosisio, Luciano, Lanceri, Livio, Vitale, Lorenzo, and LA LICATA, Chiara

Subjects
solid state detector, vertex detector, Belle II, semiconductor detector, SuperKEKB, SVD, diamond detector, CVD diamond, environmental monitoring
Abstract

The Belle II VerteX Detector (VXD) is a 6 layers silicon tracker device that will cope with an unprecedented luminosity of 8 × 10 35 cm − 2 s − 1 achievable by the new SuperKEKB e + e − collider, at the KEK laboratory The Silicon Vertex Detector (SVD) is one of the main detectors in the Belle II experiment at KEK, Japan. In combination with a pixel detector, the SVD determines precise decay vertices and performs low-momentum track reconstruction. The SVD ladders are being developed at several institutes. For the development of the tracking algorithm as well as the performance estimation of the ladders, beam tests for the ladders were performed. We report an overview of the SVD development, its performance measured in the beam tests, and the prospect of its assembly and commissioning until installation.

Published
2017

49. The Software Framework of the Belle II Silicon Vertex Detector and its Development for the 2016 Test-Beam at DESY

Author

BOSISIO, LUCIANO, LANCERI, LIVIO, VITALE, LORENZO, LA Licata Chiara, Fabrizio Palla and Francesco Forti (Chairpersons), Bosisio, Luciano, Lanceri, Livio, Vitale, Lorenzo, and LA LICATA, Chiara

Subjects
solid state detector, vertex detector, Belle II, semiconductor detector, SuperKEKB, SVD
Abstract

The Silicon Vertex Detector of Belle II will be fundamental not only for the reconstruction of B meson vertices, but also for the reconstruction of neutral particles like K S , and the tracking of low- p t particles like slow pions associated with the decays of the abundant D ∗ mesons. As a consequence great importance is given to the performance of the software that deals with the simulation and reconstruction of the SVD events. The Belle II experiment is the successor to Belle, one of the two experiments that first observed CP violation in the decay of B mesons. The SuperKEKB collider will deliver 40 times more luminosity than its predecessor KEKB, which requires major upgrades to the detector hardware. This also poses new challenges not only for the data collection and storage, but also for the software framework which is used to process and analyse the experimental data. In this article we present in detail the SVD software framework together with its development for the test of the Vertex Detector system, which took place at DESY in April 2016 using an electron beam.

Published
2017

50. The Monitoring System of the Belle II Vertex Detector

Author

Bosisio, Luciano, Lanceri, Livio, Vitale, Lorenzo, LA LICATA, Chiara, Fabrizio Palla and Francesco Forti (Chairpersons), Bosisio, Luciano, Lanceri, Livio, Vitale, Lorenzo, and LA LICATA, Chiara

Subjects
solid state detector, vertex detector, Belle II, semiconductor detector, SuperKEKB, SVD, diamond detector, CVD diamond, environmental monitoring
Abstract

The Belle II VerteX Detector (VXD) is a 6 layers silicon tracker device that will cope with an unprecedented luminosity of 8 × 10 35 cm − 2 s − 1 achievable by the new SuperKEKB e + e − collider, at the KEK laboratory (Tsukuba, Japan). All environment parameters such as temperature, humidity and radiation levels, must be constantly monitored and under certain conditions action must be promptly taken, such as interlocking the power supply or delivering an abort signal to the SuperKEKB collider. In this contribution we describe the Belle II VXD monitoring system. We also present the first results of the temperature and humidity system commissioned in a Beam Test at DESY in April 2016 and the preliminary results of the radiation monitoring achieved with a prototype system during the first SuperKEKB commissioning phase at KEK in February-June 2016.

Published
2017

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