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4. Design Optimisation of a Flat-Panel, Limited-Angle TOF-PET Scanner: A Simulation Study.

Author

Orehar, Matic, Dolenec, Rok, El Fakhri, Georges, Korpar, Samo, Križan, Peter, Razdevšek, Gašper, Marin, Thibault, Žontar, Dejan, and Pestotnik, Rok

Subjects
POSITRON emission tomography, SCINTILLATORS, MONTE Carlo method, SCANNING systems, SPATIAL resolution
Abstract

In time-of-flight positron emission tomography (TOF-PET), a coincidence time resolution (CTR) below 100 ps reduces the angular coverage requirements and, thus, the geometric constraints of the scanner design. Among other possibilities, this opens the possibility of using flat-panel PET detectors. Such a design would be more cost-accessible and compact and allow for a higher degree of modularity than a conventional ring scanner. However, achieving adequate CTR is a considerable challenge and requires improvements at every level of detection. Based on recent results in the ongoing development of optimised TOF-PET photodetectors and electronics, we expect that within a few years, a CTR of about 75 ps will be be achievable at the system level. In this work, flat-panel scanners with four panels and various design parameters were simulated, assessed and compared to a reference scanner based on the Siemens Biograph Vision using NEMA NU 2-2018 metrics. Point sources were also simulated, and a method for evaluating spatial resolution that is more appropriate for flat-panel geometry is presented. We also studied the effects of crystal readout strategies, comparing single-crystal and module readout levels. The results demonstrate that with a CTR below 100 ps, a flat-panel scanner can achieve image quality comparable to that of a reference clinical scanner, with considerable savings in scintillator material. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Performance and commissioning of HAPDs in the Aerogel RICH counter

Author

Yonenaga, Masanobu, Adachi, Ichiro, Burmistrov, Leonid, Le Diberder, Francois, Dolenec, Rok, Hataya, Koki, Iijima, Toru, Kakimoto, Shiori, Kakuno, Hidekazu, Kawai, Hideyuki, Kawasaki, Takeo, Kindo, Haruki, Kohriki, Takashi, Konno, Tomoyuki, Korpar, Samo, Križan, Peter, Kumita, Tetsuro, Lai, Yun-Tsung, Machida, Masahiro, Mrvar, Manca, Nishida, Shohei, Noguchi, Kouta, Ogawa, Kazuya, Ogawa, Satoru, Pestotnik, Rok, Šantelj, Luka, Shoji, Masayoshi, Sumiyoshi, Takayuki, Tabata, Makoto, Tamechika, Sachi, Yoshizawa, Morihito, and Yusa, Yosuke

Published
2020
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6. Silica aerogel radiator for use in the A-RICH system utilized in the Belle II experiment

Author

Tabata, Makoto, Adachi, Ichiro, Hamada, Nao, Hara, Koji, Iijima, Toru, Iwata, Shuichi, Kakuno, Hidekazu, Kawai, Hideyuki, Korpar, Samo, Križan, Peter, Kumita, Tetsuro, Nishida, Shohei, Ogawa, Satoru, Pestotnik, Rok, Šantelj, Luka, Seljak, Andrej, Sumiyoshi, Takayuki, Tahirović, Elvedin, Yoshida, Keisuke, and Yusa, Yosuke

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
Abstract

This paper presents recent progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter, which will be installed in the forward end cap of the Belle II detector. The proximity-focusing A-RICH system is especially designed to identify charged kaons and pions. The refractive index of the installed aerogel Cherenkov radiators is approximately 1.05, and we aim for a separation capability exceeding 4$\sigma $ at momenta up to 4 GeV/$c$. Large-area aerogel tiles (over 18 $\times $ 18 $\times $ 2 cm$^3$) were first fabricated in test productions by pin drying in addition to conventional methods. We proposed to fill the large end-cap region (area 3.5 m$^2$) with 124 water-jet-trimmed fan-shaped dual-layer-focusing aerogel combinations of different refractive indices (1.045 and 1.055). Guided by the test production results, we decided to manufacture aerogels by the conventional method and are currently proceeding with mass production. In an electron beam test undertaken at the DESY, we confirmed that the $K$/$\pi $ separation capability of a prototype A-RICH counter exceeded 4$\sigma $ at 4 GeV/$c$., Comment: To be published in Nucl. Instrum. Methods A,, 5 pages, 5 figures

Published
2014
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7. The Aerogel Ring Image Cherenkov Counter for Particle Identification in the Belle II Experiment

Author

Konno, Tomoyuki, Adachi, Ichiro, Dolenec, Rok, Kakuno, Hidekazu, Kawai, Hideyuki, Kindo, Haruki, Korpar, Samo, Križan, Peter, Kumita, Tetsuro, Machida, Masahiro, Mrvar, Manca, Nishida, Shohei, Noguchi, Kouta, Ogawa, Kazuya, Ogawa, Satoru, Pestotnik, Rok, Šantelj, Luka, Sumiyoshi, Takayuki, Tabata, Makoto, Yonenaga, Masanobu, Yoshizawa, Morihito, Yusa, Yosuke, and Liu, Zhen-An, editor

Published
2018
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8. Measurement of the $\Omega_c^0$ lifetime at Belle II

Author

Abudinen, Fernando Jesus, Adachi, Ichiro, Aggarwal, Latika, Ahmed, Hossain, Aihara, Hiroaki, Akopov, Norayr, Aloisio, Alberto, Nguyen, Anh-Ky, Asner, David Mark, Aushev, Tagir, Aushev, Volodymyr Ye, Bae, Hanwook, Bambade, Philip, Banerjee, Sw., Banerjee, Swagato, Baudot, Jerome, Bauer, Moritz, Beaubien, Alexandre, Becker, Juergen, Behera, Prafulla Kumar, Bennett, Jake, Bernieri, Enrico, Bernlochner, Florian, Bertacchi, Valerio, Bertemes, Michel, Bertholet, Emilie, Bessner, Martin, Bettarini, Stefano, Bhuyan, Bipul, Bianchi, Fabrizio, Bilka, Tadeas, Biswas, Diptaparna, Bodrov, Denis, Bolz, Arthur, Borah, Jyotirmoi, Bozek, Andrzej, Bracko, Marko, Branchini, Paolo, Briere, R. A., Browder, Thomas Earl, Budano, Antonio, Bussino, Severino, Campajola, Marcello, Cao, Lu, Casarosa, Giulia, Cecchi, Claudia, Chang, Ming-Chuan, Cheema, Priyanka, Chekelian, Vladimir, Chen, Yongqing, Chilikin, Kirill, Chirapatpimol, Khem, Cho, HanEol, Cho, Kihyeon, Cho, Sungjin, Choi, Sookyung, Choudhury, Seema, Cinabro, David, Corona, Luigi, Cunliffe, Samuel Thomas, Das, Sanjeeda Bharati, Dattola, Filippo, De La Cruz Burelo, Eduard, De La Motte, Shanette Anne, de Marino, Gaetano, De Nardo, Guglielmo, De Nuccio, Michael, De Pietro, Giacomo, de Sangro, Riccardo, Destefanis, Marco, Dey, Sourav, De Yta Hernandez, Alejandro, Dhamija, Rashmi, Di Canto, Angelo, Di Capua, Francesco, Dingfelder, Jochen, Dolezal, Zdenek, Dominguez Jimenez, Isabel, Dong, Thanh Van, Dorigo, Mirco, Dort, Katharina, Dreyer, Sascha, Dubey, Shawn, Dujany, Giulio, Ecker, Patrick, Eliachevitch, Michael, Epifanov, Denis Alexandrovich, Feichtinger, Paul, Ferber, Torben, Ferlewicz, Daniel, Fillinger, Tristan, Finocchiaro, Giuseppe, Fodor, Andrea, Forti, Francesco, Fulsom, Bryan Gregory, Ganiev, Eldar, Gaur, Vipin, Gaz, Alessandro, Gellrich, Andreas, Ghevondyan, Gayane, Giordano, Raffaele, Giri, Anjan, Glazov, Alexander, Gobbo, Benigno, Godang, Romulus, Goldenzweig, Pablo, Gradl, Wolfgang, Granderath, Svenja Katharina, Graziani, Enrico, Greenwald, Daniel, Gu, Tianping, Guan, Yinghui, Gudkova, Kristina, Guilliams, Justin, Hayasaka, Kiyoshi, Hayashii, Hisaki, Hazra, Sagar, Hearty, Christopher, Heredia de la Cruz, Ivan, Hernandez Villanueva, Michel, Hershenhorn, Alon David, Higuchi, Takeo, Hill, Ewan Chin, Hirata, Hikari, Hohmann, Marcel, Hsu, Chia-Ling, Iijima, Toru, Inami, Kenji, Inguglia, Gianluca, Ipsita, N. Sushree, Ishikawa, Akimasa, Ito, Shintaro, Itoh, Ryosuke, Iwasaki, Masako, Jackson, Paul Douglas, Jacobs, William Wescott, Jaffe, David, Jang, Eunji, Jia, Sen, Jin, Yifan, Joo, Kyung Kwang, Junkerkalefeld, Henrik, Kaliyar, Abdul Basith, Kang, Kookhyun, Karl, Robert, Karyan, Gevorg, Kiesling, Christian, Kim, Cheolhun, Kim, Doris Yangsoo, Kim, Kyungho, Kim, Yongkyu, Kindo, Haruki, Kinoshita, Kay, Kodys, Peter, Koga, Taichiro, Kohani, Shahab, Kojima, Kazuki, Konno, Tomoyuki, Korobov, Alexandr, Korpar, Samo, Kovalenko, Evgeniy, Kowalewski, Robert, Kraetzschmar, Thomas Michael Gerd, Krizan, Peter, Krokovny, Pavel, Kumar, Jitendra, Kumara, Kospalage Janaka, Kunigo, Takuto, Kuzmin, Alexander, Kwon, Youngjoon, Lacaprara, Stefano, Lam, Tommy, Lanceri, Livio, Lange, Jens Soeren, Laurenza, Martina, Lautenbach, Klemens, Leboucher, Robin, Li, Chunhua, Li, Longke, Libby, James Frederick, Lieret, Kilian Adriano, Liptak, Zachary John, Liu, Qingyuan, Liventsev, Dmitri, Longo, Savino, Lozar, Andrej, Lueck, Thomas, Lyu, Chaoyi, Maggiora, Marco, Maiti, Rajesh Kumar, Manfredi, Riccardo, Manoni, Elisa, Marcello, Simonetta, Marinas, Carlos, Martini, Alberto, Martinov, Tommy, Massaccesi, Ludovico, Masuda, Masataka, Maurya, Shubhangi Krishan, McKenna, Janis Anne, Meier, Frank, Merola, Mario, Metzner, Felix, Milesi, Marco, Miller, Caleb, Miyabayashi, Kenkichi, Mizuk, Roman, Mohanty, G. B., Molina-Gonzalez, N., Molina, Norman Wilfrido, Moneta, Stefano, Moser, Hans-Guenther, Mrvar, Manca, Mussa, Roberto, Nakamura, Isamu, Nakao, Mikihiko, Nakayama, Hiroyuki, Nakazawa, Yu, Narimani Charan, Abtin, Naruki, Megumi, Natkaniec, Zbigniew Marian, Natochii, Andrii, Nayak, Lopamudra, Nayak, Minakshi, Nazaryan, Gevorg, Nellikunnummel, Nisar, Ogawa, Satoru, Ono, Hiroaki, Onuki, Yoshiyuki, Oxford, Emma Rollinson, Paladino, Antonio, Panta, Anil, Paoloni, Eugenio, Pardi, Silvio, Park, Hwanbae, Park, Seokhee, Passeri, Antonio, Paul, Stephan Martin, Pedlar, Todd Kristofer, Peruzzi, Ida Marena, Peschke, Richard, Pestotnik, Rok, Piccolo, Marcello, Piilonen, L. E., Podesta lerma, Pedro Luis Manuel, Podobnik, Tomaz, Pokharel, Saroj, Polat, Leonard, Praz, Cyrille, Prell, Soeren, Prencipe, Elisabetta, Prim, Markus Tobias, Purwar, Harsh, Rad, Navid Khandan, Rados, Petar, Raiz, Sebastiano, Ramirez Morales, Andres, Reif, Markus, Reiter, Simon, Remnev, Mikhail, Ripp-Baudot, Isabelle, Rizzo, Giuliana, Robertson, Steven H., Roney, John Michael, Rostomyan, Armine, Rout, Niharika, Russo, Guido, Sanders, David Alan, Sandilya, Saurabh, Sangal, Aman, Sato, Yo, Savinov, Vladimir, Scavino, Bianca, Schueler, Jeff, Schwanda, Christoph, Schwartz, Alan Jay, Schwenker, Benjamin, Seino, Yoshiaki, Selce, Andrea, Senyo, Katsumi, Serrano, Justine, Sevior, Martin Edmund, Sfienti, Concettina, Shen, Chengping, Shi, Xiaodong, Shillington, Trevor, Sibidanov, Alexei, Singh, Jasbir, Skorupa, Justin, Sobie, Randall, Soffer, Abner, Solovieva, Elena, Spataro, Stefano, Spruck, Bjoern, Staric, Marko, Stefkova, Slavomira, Stottler, Zachary Shaun, Stroili, Roberto, Strube, Jan Fridolf, Sumihama, Mizuki, Sumisawa, Kazutaka, Sutcliffe, William, Suzuki, Soh Yamagata, Svidras, Henrikas, Takizawa, Makoto, Tamponi, Umberto, Tanida, Kiyoshi, Tanigawa, Hikaru, Tenchini, Francesco, Thaller, Arthur, Tiwary, Rahul, Tonelli, Diego, Torassa, Ezio, Toutounji, Nadia Ejlal, Trabelsi, Karim, Uchida, Makoto, Ueda, Ikuo, Uematsu, Yuma, Uglov, Timofey, Unger, Kai Lukas, Unno, Yuji, Uno, Kenta, Uno, Shoji, Ushiroda, Yutaka, Vahsen, Sven Einar, van Tonder, Raynette, Varner, Gary, Varvell, Kevin Ernest, Vinokurova, Anna, Vitale, Lorenzo, Vobbilisetti, Vidya Sagar, Wakeling, Hannah Marie, Wang, Erfei, Wang, Min-Zu, Wang, Xiaolong, Warburton, Andreas, Watanabe, Minori, Watanuki, Shun, Welsch, Maximilian, Wessel, Christian, Won, Eunil, Yabsley, Bruce Donald, Yamada, Satoru, Yan, Wenbiao, Yang, Seongbae, Ye, Hua, Yelton, John, Yin, Junhao, Yook, Youngmin, Yoshihara, Keisuke, Yuan, Changzheng, Zani, Laura, Zhang, Yi, Zhilich, Victor, Zhou, Qi-Dong, Zhou, Xing-Yu, Zhukova, Valentina, Zlebcik, Radek, 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), Belle-II, and HEP, INSPIRE

Subjects
lifetime, Omega, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], hadronic decay [Omega/c0], BELLE, annihilation [electron positron], electron positron: colliding beams, Omega/c0: hadronic decay, electron positron: annihilation, pi+, High Energy Physics - Experiment, KEK-B, Omega/c0: lifetime, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], colliding beams [electron positron], ddc:530, charmed baryon, +Omega-+pi%2B%22">Omega/c0 --> Omega- pi+, lifetime [Omega/c0], experimental results
Abstract

Physical review / D 107, L031103 (2023). doi:10.1103/PhysRevD.107.L031103, We report on a measurement of the $\Omega_c^0$ lifetime using $\Omega_c^0 \to \Omega^-\pi^+$ decays reconstructed in $e^+e^-\to c\bar{c}$ data collected by the Belle II experiment and corresponding to $207~{\rm fb^{-1}}$ of integrated luminosity. The result, $\rm\tau(\Omega_c^0)=243\pm48( stat)\pm11(syst)~fs$, agrees with recent measurements indicating that the $\Omega_c^0$ is not the shortest-lived weakly decaying charmed baryon., Published by Inst., Woodbury, NY

Published
2023
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9. Belle2Lab - An Interactive Tool for a Public Analysis of the Belle II Data

Author

Pestotnik Rok

Subjects
Physics, QC1-999
Abstract

Several data samples from a Belle II experiment will be available to the public as a part of the experiment outreach activities. A Belle2Lab tool is designed as an interactive graphical user interface to reconstructed particles, offering users basic particle selection tools. The tool is based on a Blockly JavaScript graphical code generator and can be run in an HTML5 capable browser. It allows a description of different particle decays by selecting and combining particles from the data file, easy histogramming tools and a display of the results by using the JSROOT library. During the analysis, the user has the possibility to apply cuts to the selected variables. A pseudo-code generated by the user interface is sent to the execution server which returns the histograms, that can also be interactively fitted. The Belle2Lab is accessible in two ways: hosted on a single public web server or as a part of the virtual appliance which consists of an Ubuntu 16.04 LTS operating system, a data sample, an analysis framework, and a private web server. The public web server can be used for a single access while the virtual appliance is more suited for a use in a classroom.

Published
2019
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11. Measurement of the $B^+/B^0$ production ratio in $e^+e^-$ collisions at the $\Upsilon(4S)$ resonance using $B \rightarrow J/\psi(\ell\ell) K$ decays at Belle

Author

Adachi, Ichirou, Aihara, Hiroaki, Asner, David, Atmacan, Hulya, Aushev, Tagir, Ayad, Rachid, Babu, Varghese, Bahinipati, Seema, Behera, Prafulla Kumar, Belous, Konstantin, Bennett, Jake, Bessner, Martin, Bhardwaj, Vishal, Bhuyan, Bipul, Bilka, Tadeas, Bodrov, Denis, Bonvicini, Giovanni, Borah, Jyotirmoi, Bozek, Andrzej, Bracko, Marko, Branchini, Paolo, Browder, Thomas, Budano, Antonio, Campajola, Marcello, Cervenkov, Daniel, Chang, Ming-Chuan, Chen, Chunhui, Cheon, Byunggu, Chilikin, Kirill, Cho, Haneol, Cho, Kihyeon, Cho, Sungjin, Choi, Sookyung, Choi, Youngil, Choudhury, Seema, Cinabro, David, Das, Sanjeeda Bharati, de Pietro, Giacomo, Di Capua, Francesco, Dingfelder, Jochen, Dolezal, Zdenek, Dong, Thanh Van, Epifanov, Denis Alexandrovich, Ferlewicz, Daniel, Fulsom, Bryan Gregory, Garg, Renu, Gaur, Vipin, Gabyshev, Nikolay, Giri, Anjan, Goldenzweig, Pablo, Graziani, Enrico, Gu, Tianping, Gudkova, Kristina, Hadjivasiliou, Christos, Hara, Takanori, Hayasaka, Kiyoshi, Hayashii, Hisaki, Hedges, Michael Thomas, Herrmann, Daniel Ricalde, Hou, George Wei-Shu, Hsu, Chia-Ling, Inami, Kenji, Ipsita, N. Sushree, Ishikawa, Akimasa, Itoh, Ryosuke, Iwasaki, Masako, Jacobs, William, Jang, Eunji, Ji, Qingping, Jia, Sen, Jin, Yifan, Joo, Kyung Kwang, Kang, Kook Hyun, Kawasaki, Takeo, Kiesling, Christian, Kim, Cheolhun, Kim, Doris Yangsoo, Kim, Kyungho, Kim, Yongkyu, Kindo, Haruki, Kinoshita, Kay, Kodys, Peter, Konno, Tomoyuki, Korobov, Alexander, Korpar, Samo, Kovalenko, Evgeniy, Krizan, Peter, Krokovny, Pavel, Kumar, Manish, Kumar, Rajeev, Kumara, Kospalage Janaka, Kwon, Young-Joon, Lam, Tommy, Lange, Jens Soeren, Laurenza, Martina, Lee, Seungcheol, Lewis, Peter, Li, Jin, Li, Longke, Li, Yubo, Li Gioi, Luigi, Libby, James Frederick, Lieret, Kilian Adriano, Liventsev, Dmitri, Luo, Tao, Masuda, Masataka, Matsuda, Tatsuro, Matvienko, Dmitry, Maurya, Shubhangi Krishan, Meier, Frank, Merola, Mario, Metzner, Felix, Miyabayashi, Kenkichi, Mizuk, Roman, Mohanty, Gagan Bihari, Nakamura, Isamu, Nakao, Mikihiko, Natkaniec, Zbigniew, Natochii, Andrii, Nayak, Lopamudra, Nayak, Minakshi, Nellikunnummel, Nisar, Nishida, Shohei, Ogawa, Satoru, Ono, Hiroaki, Oskin, Pavel, Pakhlov, Pavel, Pakhlova, Galina, Pardi, Silvio, Park, Seokhee, Passeri, Antonio, Patra, Sourav, Paul, Stephan Martin, Pedlar, Todd Kristofer, Pestotnik, Rok, Piilonen, Leo, Podobnik, Tomaz, Prell, Soeren, Prencipe, Elisabetta, Prim, Markus, Rout, Niharika, Russo, Guido, Sakai, Yoshihide, Sandilya, Saurabh, Sangal, Aman, Santelj, Luka, Savinov, Vladimir, Schueler, Jeff, Schwanda, Christoph, Schwartz, Alan Jay, Seino, Yoshiaki, Senyo, Katsumi, Sevior, Martin Edmund, Shapkin, Mikhail, Sharma, Chanchal, Shen, Chengping, Shiu, Jing-Ge, Singh, Jasbir, Sokolov, Anatoly, Solovieva, Elena, Staric, Marko, Stottler, Zachary S., Strube, Jan, Sumihama, Mizuki, Sumiyoshi, Takayuki, Takizawa, Makoto, Tanida, Kiyoshi, Tenchini, Francesco, Trabelsi, Karim, Uchida, Makoto, Uglov, Timofey, Unno, Yuuji, Uno, Shoji, Urquijo, Phillip, Ushiroda, Yutaka, Usov, Yuri, van Tonder, Raynette, Varner, Gary, Varvell, Kevin Ernest, Vinokurova, Anna, Vossen, Anselm Georg, Waheed, Eiasha, Wang, Erfei, Wang, Min-Zu, Wang, Xiaolong, Watanabe, Minori, Watanuki, Shun, Won, Eunil, Xu, Xinping, Yabsley, Bruce, Yang, Seongbae, Yelton, John, Yin, Junhao, Yuan, Changzheng, Yusa, Yosuke, Zhai, Yunxiao, Zhang, Ziping, Zhilich, Victor, Zhukova, Valentina, and HEP, INSPIRE

Subjects
+electron+positron%22">J/psi(3100) --> electron positron, B0: hadronic decay, Upsilon(10570): electroproduction, +J%2Fpsi%283100%29+K%2B%22">B+ --> J/psi(3100) K+, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], +B0+anti-B0%22">Upsilon(10570) --> B0 anti-B0, measure: ratio, BELLE, electron positron: colliding beams, branching ratio: ratio, electron positron: annihilation, +B%2B+B%22">Upsilon(10570) --> B+ B, decay rate: ratio, electron: pair production, muon: pair production, J/psi(3100): leptonic decay, Upsilon(10570): branching ratio, error: statistical, KEK-B, +muon%2B+muon%22">J/psi(3100) --> muon+ muon, +J%2Fpsi%283100%29+K0%22">B0 --> J/psi(3100) K0, isospin: symmetry, B+: hadronic decay, experimental results
Abstract

We measure the ratio of branching fractions for the $\Upsilon (4S)$ decays to $B^+B^-$ and $B^0\bar{B}{}^0$ using $B^+ \rightarrow J/\psi(\ell\ell) K^+$ and $B^0 \rightarrow J/\psi(\ell\ell) K^0$ samples, where $J/\psi(\ell\ell)$ stands for $J/\psi \to \ell^+\ell^-$ ($\ell = e$ or $\mu$), with $711$ fb$^{-1}$ of data collected at the $\Upsilon(4S)$ resonance with the Belle detector. We find the decay rate ratio of $\Upsilon(4S) \rightarrow B^+B^-$ over $\Upsilon(4S) \rightarrow B^0\bar{B}{}^0$ to be $1.065\pm0.012\pm 0.019 \pm 0.047$, which is the most precise measurement to date. The first and second uncertainties are statistical and systematic, respectively, and the third uncertainty is systematic due to the assumption of isospin symmetry in $B \to J/\psi(\ell\ell) K$.

Published
2022

19. Study of possibilities for a spin flip in high energy electron ring HERA

Author

Stres, Spela and Pestotnik, Rok

Subjects
Electrons -- Research, Electrons -- Properties, Polarization (Nuclear physics) -- Research, Business, Electronics, Electronics and electrical industries
Abstract

In a high energy electron ring the spins of electrons become spontaneously polarized via the emission of spin-flip synchrotron radiation. By employing a radio frequency radial dipole field kicker, particle spin directions can be rotated slowly over many turns. A model which couples three dimensional spin motion and longitudinal particle motion was constructed to describe nonequilibrium spin dynamics in high energy electron storage rings. The effects of a stochastic synchrotron radiation on the orbital motion in the accelerator synchrotron plane and its influence on the spin motion are studied. The main contributions to the spin motion, the synchrotron oscillations and the stochastic synchrotron radiation, have different influence on the spin polarization reversal in different regions of the parameter space. The results indicate that polarization reversal might be obtained in high energy electron storage rings with a significant noise even with relatively small strengths of a perturbing magnetic field. The only experimental datum available agrees with the model prediction, however further experimental data would be necessary to validate the model. Index Terms--High energy electron ring, polarization reversal, spin flip, spin motion.

Published
2006

20. The Aerogel RICH detector of the Belle II experiment

Author

Santelj, Luka, primary, Adachi, Ichiro, additional, Burmsistrov, Leonid, additional, Dolenec, Rok, additional, Hataya, Koki, additional, Iijima, Toru, additional, Kakimoto, Shiori, additional, Kakuno, Hidekazu, additional, Kawai, Hideyuki, additional, Kawasaki, Takeo, additional, Kindo, Haruki, additional, Kohriki, Takashi, additional, Konno, Tomoyuki, additional, Korpar, Samo, additional, Kou, Emi, additional, Krizan, Peter, additional, Kumita, Tetsuro, additional, Lai, Yun-Tsung, additional, Machida, Masahiro, additional, Mrvar, Manca, additional, Nishida, Shohei, additional, Noguchi, Kouta, additional, Ogawa, Kazuya, additional, Ogawa, Satoru, additional, Pestotnik, Rok, additional, Shoji, Masayoshi, additional, Sumiyoshi, Takayuki, additional, Tabata, Makoto, additional, Tamechika, Sachi, additional, Yonenaga, Masanobu, additional, Yoshizawa, Morihito, additional, Yusa, Yosuke, additional, and Le Diberder, Francois, additional

Published
2020
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22. Performance Evaluation of the HAPD in the Belle II Aerogel RICH Counter

Author

Yonenaga, Masanobu, primary, Adachi, Ichiro, additional, Burmsistrov, Leonid, additional, Le Diberder, Francois, additional, Dolenec, Rok, additional, Hataya, Koki, additional, Iijima, Toru, additional, Kakimoto, Shiori, additional, Kakuno, Hidekazu, additional, Kawai, Hideyuki, additional, Kawasaki, Takeo, additional, Kindo, Haruki, additional, Kohriki, Takashi, additional, Konno, Tomoyuki, additional, Korpar, Samo, additional, Križan, Peter, additional, Kumita, Tetsuro, additional, Lai, Yun-Tsung, additional, Machida, Masahiro, additional, Mrvar, Manca, additional, Nishida, Shohei, additional, Noguchi, Kouta, additional, Ogawa, Kazuya, additional, Ogawa, Satoru, additional, Pestotnik, Rok, additional, Šantelj, Luka, additional, Shoji, Masayoshi, additional, Sumiyoshi, Takayuki, additional, Tabata, Makoto, additional, Tamechika, Sachi, additional, Yoshizawa, Morihito, additional, and Yusa, Yosuke, additional

Published
2019
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23. Performance Estimation of the Belle II Aerogel RICH Counter in the First Beam Collision

Author

Konno, Tomoyuki, primary, Adachi, Ichiro, additional, Burmsistrov, Leonid, additional, Le Diberder, Francois, additional, Dolenec, Rok, additional, Hataya, Koki, additional, Iijima, Toru, additional, Kakimoto, Shiori, additional, Kakuno, Hidekazu, additional, Kawai, Hideyuki, additional, Kawasaki, Takeo, additional, Kindo, Haruki, additional, Kohriki, Takashi, additional, Korpar, Samo, additional, Križan, Peter, additional, Kumita, Tetsuro, additional, Lai, Yun-Tsung, additional, Machida, Masahiro, additional, Mrvar, Manca, additional, Nishida, Shohei, additional, Noguchi, Kouta, additional, Ogawa, Kazuya, additional, Ogawa, Satoru, additional, Pestotnik, Rok, additional, Šantelj, Luka, additional, Shoji, Masayoshi, additional, Sumiyoshi, Takayuki, additional, Tabata, Makoto, additional, Tamechika, Sachi, additional, Yonenaga, Masanobu, additional, Yoshizawa, Morihito, additional, and Yusa, Yosuke, additional

Published
2019
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24. Measurement of branching fractions for $B to J/psi eta K$ decays and search for a narrow resonance in the $J/psi eta$ final state

Author

Iwashita, T., Bračko, Marko, Golob, Boštjan, Klučar, Jure, Korpar, Samo, Križan, Peter, Pestotnik, Rok, Petrič, Marko, Starič, Marko, Šantelj, Luka, and Zupanc, Anže

Subjects
experimental particle physics, leptonski trkalnik, C07, eksperimentalna fizika delcev, particle properties, lepton collider experiments, High Energy Physics::Experiment, udc:539.1, lastnosti delcev, eksperimenti, C21
Abstract

We report an observation of the $B^{pm } to J/psi eta K^{pm }$ and $B^0 to J/psi eta K^0_S$ decays using $772times 10^{6}Boverline {B}$ pairs collected at the $Upsilon (4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We obtain the branching fractions ${mathcal B}(B^{pm }rightarrow J/psi eta K^{pm })=(1.27pm 0.11(hbox {stat.})pm 0.11(hbox {syst.}))times 10^{-4}$ and ${mathcal B}(B^0to J/psi eta K^0_S)=(5.22 pm 0.78 (hbox {stat.}) pm 0.49 (hbox {syst.}))times 10^{-5}$. We search for a new narrow charmonium(-like) state $X$ in the $ J/psi eta$ mass spectrum and find no significant excess. We set upper limits on the product of branching fractions, ${mathcal B}(B^pm to XK^pm){mathcal B}(X to J/psi eta)$, at $3872,hbox {MeV},c^{-2}$ where a $C$-odd partner of $X(3872)$ may exist, at $psi (4040)$ and $psi (4160)$ assuming their known mass and width, and over a range from 3.8 to $4.8,hbox {GeV},c^{-2}$. The obtained upper limits at 90% confidence level for $X^{Chbox {-}{rm odd}}(3872)$, $psi (4040)$, and $psi (4160)$ are $3.8times 10^{-6}$, $15.5times 10^{-6}$, and $7.4times 10^{-6}$, respectively.

Published
2017

25. High-statistics study of $K^0_S K^0_S$ pair production in two-photon collisions

Author

Uehara, S., Bračko, Marko, Golob, Boštjan, Klučar, Jure, Korpar, Samo, Križan, Peter, Pestotnik, Rok, Petrič, Marko, Starič, Marko, Šantelj, Luka, and Zupanc, Anže

Subjects
experimental particle physics, quark model, kvarkovski model, C07, eksperimentalna fizika delcev, udc:539.1, lastnosti delcev, kvantna kromodinamika, leptonski trkalnik, quantum chromodynamics, particle properties, lepton collider experiments, High Energy Physics::Experiment, C05, eksperimenti, C21, C00
Abstract

We report a high-statistics measurement of the differential cross section of the process $gamma gamma to K^0_S K^0_S$ in the range $1.05,{mathrm {GeV}} leq W leq 4.00$ , where W is the center-of-mass energy of the colliding photons, using 972 $^{-1}$ of data collected with the Belle detector at the KEKB asymmetric-energy e+e− collider operated at and near the $Upsilon$-resonance region. The differential cross section is fitted by parameterized S-, $D_0$, $D_2$-, $G_0$-, and $G_2$-wave amplitudes. In the $D_2$ wave, the $f_2$(1270), $a_2$(1320), and $f′_2$(1525) are dominant and a resonance, the $f_2$(2200), is also present. The $f_0$(1710) and possibly the $f_0$(2500) are seen in the S wave. The mass, total width, and product of the two-photon partial decay width and decay branching fraction to the $K bar {K}$ state $Gamma _{gamma gamma }mathcal {B}(K bar {K})$ are extracted for the $f′_2$(1525), $f_0$(1710), $f_2$(2200), and $f_0$(2500). The destructive interference between the $f_2$(1270) and $a_2$(1320) is confirmed by measuring their relative phase. The parameters of the charmonium states $chi _{c0}$ and $chi _{c2}$ are updated. Possible contributions from the $chi _{c0}(2P)$ and $chi _{c2}(2P)$ states are discussed. A new upper limit for the branching fraction of the P- and CP-violating decay channel $eta _c to K^0_S K^0_S$ is reported. The detailed behavior of the cross section is updated and compared with QCD-based calculations.

Published
2017

26. Particle identification performance of the prototype aerogel RICH counter for the Belle II experiment

Author

Iwata, S., Korpar, Samo, Križan, Peter, Pestotnik, Rok, Šantelj, Luka, Seljak, Andrej, and Tahirović, Elvedin

Subjects
RICH counters, detektorji delcev, ring imaging Cherenkov counters, udc:539.1.074, fizika osnovnih delcev, H14, detektor Belle II, števci 'ring imaging Cherenkov', števci RICH, High Energy Physics::Experiment, elementary particle physics, particle detectors, Belle II detector
Abstract

We have developed a new type of particle identification device, called an aerogel ring imaging Cherenkov (ARICH) counter, for the Belle II experiment. It uses silica aerogel tiles as Cherenkov radiators. For detection of Cherenkov photons, hybrid avalanche photo-detectors (HAPDs) are used. The designed HAPD has a high sensitivity to single photons under a strong magnetic field. We have confirmed that the HAPD provides high efficiency for single-photon detection even after exposure to neutron and $gamma$-ray radiation that exceeds the levels expected in the 10-year Belle II operation. In order to confirm the basic performance of the ARICH counter system, we carried out a beam test at the using a prototype of the ARICH counter with six HAPD modules. The results are in agreement with our expectations and confirm the suitability of the ARICH counter for the Belle II experiment. Based on the in-beam performance of the device, we expect that the identification efficiency at $3.5,{rm GeV}/c$ is 97.4% and 4.9% for pions and kaons, respectively. This paper summarizes the development of the HAPD for the ARICH and the evaluation of the performance of the prototype ARICH counter built with the final design components.

Published
2017

27. First model-independent Dalitz analysis of $B^0 to D^0K^{ast 0}$, $Dto K_S^0pi ^+pi ^-$ decay

Author

Negishi, K., Biswal, Jyoti Prakash, Bračko, Marko, Golob, Boštjan, Korpar, Samo, Križan, Peter, Nanut, Tara, Pestotnik, Rok, Petrič, Marko, Ribežl, Eva, Stanič, Samo, Starič, Marko, Šantelj, Luka, and Zupanc, Anže

Subjects
experimental particle physics, Cabibbo-Kobayashi-Maskawa quark-mixing matrix, kršitev simetrije CP, CP violation, matrika CKM, matrika Cabibbo-Kobayashi-Maskawa, eksperimentalna fizika delcev, CO2, C03, udc:539.1, CO3
Abstract

We report a measurement of the amplitude ratio $r_S$ of $B^0 to D^0K^{ast 0}$ and $B^0 to bar {D^0}K^{ast 0}$ decays with a Dalitz analysis of $Dto K_S^0pi ^+pi ^-$ decays, for the first time using a model-independent method. We set an upper limit $r_S < 0.87$ at the 68% confidence level, using the full data sample of $711,{rm fb}^{-1}$ corresponding to $772times 10^6$ $Bbar {B}$ pairs collected at the $Upsilon (4S)$ resonance with the Belle detector at the KEKB $e^+e^-$ collider. This result is obtained from observables $x_- = +0.4 ^{+1.0 +0.0}_{-0.6 -0.1} pm 0.0$, $y_- = -0.6 ^{+0.8 +0.1}_{-1.0 -0.0} pm 0.1$, $x_+ = +0.1 ^{+0.7 +0.0}_{-0.4 -0.1} pm 0.1$, and $y_+ = +0.3 ^{+0.5 +0.0}_{-0.8 -0.1} pm 0.1$, where $x_pm = r_S cos (delta _S pm phi _3)$, $y_pm = r_S sin (delta _S pm phi _3)$, and $phi _3 (delta _S)$ is the weak (strong) phase difference between $B^0 to D^0K^{ast 0}$ and $B^0 to bar {D^0}K^{ast 0}$.

Published
2017

28. Measurement of D0–D‾0 mixing and search for CP violation in D0 → K+K−,π+π− decays with the full Belle data set

Author

Starič, Marko, Biswal, Jyoti Prakash, Bračko, Marko, Golob, Boštjan, Korpar, Samo, Križan, Peter, Nanut, Tara, Pestotnik, Rok, Petrič, Marko, Ribežl, Eva, Stanič, Samo, and Zupanc, Anže

Subjects
kršitev simetrije CP, CP violation, mezon D, charm mesons, mešanje, mixing, udc:539.1, kvark c
Abstract

We report an improved measurement of $D^0–{overline{D}}^0$ mixing and a search for $CP$ violation in $D^0$ decays to $CP$ -even final states $K^+K^−$ and $pi^+pi^-$. The measurement is based on the final Belle data sample of $976 fb^{−1}$. The results are $y_CP=(1.11±0.22±0.09)%$ and $A_Γ=(−0.03±0.20±0.07)%$, where the first uncertainty is statistical and the second is systematic.

Published
2017

29. Measurement of time-dependent CP violation in B 0 → η′K 0 decays

Author

Šantelj, Luka, Bračko, Marko, Golob, Boštjan, Korpar, Samo, Križan, Peter, Nanut, Tara, Pestotnik, Rok, Petrič, Marko, Ribežl, Eva, Starič, Marko, and Zupanc, Anže

Subjects
kršitev simetrije CP, CP violation, e+-e- Experiments, CKM angle beta, e+-e- eksperimenti, udc:539.1, B fizika, CKM beta, B physics
Abstract

We present a measurement of the time-dependent CP violation parameters in B0 → η′K0 decays. The measurement is based on the full data sample containing 772 × 10^6 BB pairs collected at the Υ(4S) resonance using the Belle detector at the KEKB asymmetric-energy e+e− collider. The measured values of the mixing-induced and direct CP violation parameters are: sin⁡ 2ϕ1eff=+0.68±0.07±0.03, Aη′K0=+0.03±0.05±0.04, where the first uncertainty is statistical and the second is systematic. The values obtained are the most accurate to date. Furthermore, these results are consistent with our previous measurements and with the world-average value of sin 2ϕ1 measured in B0 → J/ψK0 decays.

Published
2017

30. Search for B decays to final states with the η c meson

Author

Vinokurova, A., Bračko, Marko, Golob, Boštjan, Korpar, Samo, Križan, Peter, Pestotnik, Rok, Petrič, Marko, Ribežl, Eva, Stanič, Samo, Starič, Marko, Šantelj, Luka, and Zupanc, Anže

Subjects
kvarkonij, particle and resonance production, eksotika, e+-e- eksperimenti, exotics, e+-e- experiments, udc:539.1, B fizika, produkcija delcev in resonance, quarkonium, B physics
Abstract

We report a search for B decays to selected final states with the ηc meson: B± → K±ηcπ+π−, B± → K±ηcω, B± → K±ηcη and B± → K±ηcπ0. The analysis is based on 772 × 10^6 B¯B pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We set 90% confidence level upper limits on the branching fractions of the studied B decay modes, independent of intermediate resonances, in the range (0.6–5.3)×10^−4. We also search for molecular-state candidates in the D^0 ¯D^∗0 − ¯D^0D^∗0, D^0 ¯D^0 + ¯D^0D^0 and D^∗0¯D^∗0 + ¯D^∗0D^∗0 combinations, neutral partners of the Z(3900)± and Z(4020)±, and a poorly understood state X(3915) as possible intermediate states in the decay chain, and set 90% confidence level upper limits on the product of branching fractions to the mentioned intermediate states and decay branching fractions of these states in the range (0.6–6.9)×10^−5.

Published
2017

31. The physics of the B factories

Author

Bevan, Adrian, Golob, Boštjan, Križan, Peter, Zupan, Jure, Zupanc, Anže, Starič, Marko, Bitenc, Urban, Bizjak, Ilija, Bračko, Marko, Fratina, Saša, Gorišek, Andrej, Klučar, Jure, Korpar, Samo, Pestotnik, Rok, Petrič, Marko, Šantelj, Luka, Smerkol, Peter, Stanič, Samo, Živko, Tomi, and Žontar, Dejan

Subjects
experimental particle physics, eksperimentalna fizika, mezoni B, elementary particles, udc:539.1, B mesons, osnovni delci, B factories, tovarne mezonov B
Published
2017

32. Study of 144-channel hybrid avalanche photo-detector for Belle II RICH counter

Author

Dolenec, Rok, Korpar, Samo, Krizan, Peter, Pestotnik, Rok, Santelj, Luka, Tagai, Rie, Shiizuka, Susumu, Adachi, Ichiro, Hara, Koji, Iijima, Toru, Ikeda, Hirokazu, Imamura, Miki, Iwata, Syuuichi, Kumita, Tetsuro, Kuroda, Eiryo, Nishida, Shohei, Ogawa, Satoru, Sumiyoshi, Takayuki, and Tabata, Makoto

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, business.industry, Detector, Photodetector, Ring-imaging Cherenkov detector, law.invention, Nuclear physics, Upgrade, KEKB, law, Cathode ray, Physics::Accelerator Physics, Optoelectronics, High Energy Physics::Experiment, Collider, business, Instrumentation, Beam (structure)
Abstract

著者人数: 19名, 資料番号: SA1002757000

Published
2011

33. Particle identification performance of the prototype aerogel RICH counter for the Belle II experiment

Author

Iwata, Shuichi, Adachi, Ichiro, Hara, Kohji, Iijima, Toru, Ikeda, Hirokazu, Kakuno, H., Kawai, Hideyuki, Kawasaki, T., Korpar, Samo, Krizan, Peter, Kumita, Tetsuro, Nishida, Shohei, Ogawa, Satoru, Pestotnik, Rok, Santelj, L., Seljak, A., Sumiyoshi, Takayuki, Tabata, Makoto, Tahirovic, E., Yusa, Y., 岩田, 修一, 足立, 一郎, 原, 康二, 飯嶋, 徹, 池田, 博一, 河合, 秀幸, 汲田, 哲郎, 西田, 昌平, 小川, 了, 住吉, 孝行, 田端, 誠, Iwata, Shuichi, Adachi, Ichiro, Hara, Kohji, Iijima, Toru, Ikeda, Hirokazu, Kakuno, H., Kawai, Hideyuki, Kawasaki, T., Korpar, Samo, Krizan, Peter, Kumita, Tetsuro, Nishida, Shohei, Ogawa, Satoru, Pestotnik, Rok, Santelj, L., Seljak, A., Sumiyoshi, Takayuki, Tabata, Makoto, Tahirovic, E., Yusa, Y., 岩田, 修一, 足立, 一郎, 原, 康二, 飯嶋, 徹, 池田, 博一, 河合, 秀幸, 汲田, 哲郎, 西田, 昌平, 小川, 了, 住吉, 孝行, and 田端, 誠

Abstract

著者人数: 20名, Accepted: 2015-12-30

Published
2016

34. Evidence of $\Upsilon(1S) \to J/\psi+\chi_{c1}$ and search for double-charmonium production in $\Upsilon(1S)$ and $\Upsilon(2S)$ decays

Author

Yang, S. D., Shen, C. P., Aushev, T., Piilonen, L. E., Ribežl, E., Ritter, Marti, Rostomyan, Armine, Sakai, Y., Sandilya, S., Santelj, L., Sanuki, T., Schneider, O., Schnell, Gunar, Ayad, R., Schwanda, C., Semmler, D., Senyo, K., Shebalin, V., Shibata, T. -A., Shiu, J. -G., Shwartz, B., Sibidanov, A., Simon, Frank, Sohn, Y. -S., Bakich, A. M., Sokolov, A., Staric, Marko, Steder, Michael, Sumiyoshi, T., Tamponi, U., Tanida, K., Tatishvili, G., Teramoto, Y., Uchida, M., Uehara, S., Bansal, V., Uglov, T., Unno, Y., Uno, S., Urquijo, P., Usov, Y., Vahsen, S. E., Van Hulse, C., Vanhoefer, P., Varner, G., Vinokurova, A., Behera, P., Vorobyev, V., Vossen, A., Wagner, M. N., Wang, C. H., Wang, M. -Z., Wang, P., Wang, X. L., Watanabe, M., Watanabe, Y., Won, E., Bhuyan, B., Yamaoka, J., Yashchenko, Sergey, Yook, Y., Yuan, C. Z., Zhang, Z. P., Zhilich, V., Zhulanov, V., Belle Collaboration, Bobrov, Andrey, Bozek, A., Bračko, M., Browder, T. E., Ban, Y., Červenkov, D., Chekelian, Vladimir, Chen, A., Cheon, B. G., Chilikin, K., Chistov, R., Cho, K., Chobanova, V., Choi, S. -K., Choi, Y., Abdesselam, A., Cinabro, D., Dalseno, J., Danilov, Michael, Dingfelder, J., Doležal, Z., Drásal, Z., Drutskoy, Alexey, Dutta, Koushik, Eidelman, S., Farhat, H., Adachi, I., Fast, J. E., Ferber, Torben, Gaur, V., Gabyshev, N., Ganguly, S., Garmash, A., Gillard, R., Goh, Y. M., Golob, B., Haba, J., Aihara, H., Hara, T., Hayashii, H., He, X. H., Hou, W. -S., Huschle, M., Iijima, T., Inami, K., Ishikawa, A., Itoh, Ryosuke, Jaegle, I., Said, S. Al, Joffe, D., Joo, K. K., Julius, T., Kawasaki, T., Kim, D. Y., Kim, Hyun-Jeong, Kim, J. B., Kim, Joo-Hee, Kim, K. T., Kinoshita, K., Arinstein, K., Ko, B. R., Kodys, Peter, Korpar, Samo, Krizan, Peter, Krokovny, P., Kuzmin, Alexei, Kwon, Y. -J., Lange, Jens Sören, Li, Jie, Li, Yongjin, Asner, D. M., Gioi, L. Li, Libby, J., Liventsev, D., Lukin, P., Miyabayashi, K., Miyata, H., Moll, A., Mussa, R., Nakano, E., Nakao, Mikihiko, Aulchenko, V., Nanut, T., Nisar, N. K., Nishida, S., Okuno, S., Ostrowicz, Waclaw, Park, C. W., Park, H., Pedlar, T. K., Pestotnik, Rok, and Petrič, M.

Subjects
10.52 GeV-cms, +J%2Fpsi%283100%29+chi%2Fc1%283510%29%22">Upsilon(9460) --> J/psi(3100) chi/c1(3510), factorization [quantum chromodynamics], High Energy Physics::Phenomenology, nonrelativistic [quantum chromodynamics], BELLE, annihilation [electron positron], branching ratio: upper limit [Upsilon(9460)], X(3940), High Energy Physics - Experiment, branching ratio: upper limit [Upsilon(10020)], High Energy Physics - Phenomenology, KEK-B, hadronic decay [upsilon mesons], High Energy Physics::Experiment, branching ratio: measured [Upsilon(9460)], experimental results
Abstract

Using data samples of $102\times10^6$ $\Upsilon(1S)$ and $158\times10^6$ $\Upsilon(2S)$ events collected with the Belle detector, a first experimental search has been made for double-charmonium production in the exclusive decays $\Upsilon(1S,2S)\rightarrow J/\psi(\psi')+X$, where $X=\eta_c$, $\chi_{cJ} (J=~0,~1,~2)$, $\eta_c(2S)$, $X(3940)$, and $X(4160)$. No significant signal is observed in the spectra of the mass recoiling against the reconstructed $J/\psi$ or $\psi'$ except for the evidence of $\chi_{c1}$ production with a significance of $4.6\sigma$ for $\Upsilon(1S)\rightarrow J/\psi+\chi_{c1}$. The measured branching fraction $\BR(\Upsilon(1S)\rightarrow J/\psi+\chi_{c1})$ is $(3.90\pm1.21(\rm stat.)\pm0.23 (\rm syst.))\times10^{-6}$. The $90\%$ confidence level upper limits on the branching fractions of the other modes having a significance of less than $3\sigma$ are determined. These results are consistent with theoretical calculations using the nonrelativistic QCD factorization approach., Comment: 12 pages, 4 figures, 1 table. The fit range was extended to include X(4160) signal according to referee's suggestions. Other results unchanged. Paper was accepted for publication as a regular article in Physical Review D

Published
2014

35. Silica aerogel radiator for use in the A-RICH system utilized in the Belle II experiment

Author

Korpar, Samo, Krizan, Peter, Pestotnik, Rok, Santelj, Luka, Seljak, Andrej, Tahirovic, Elvedin, Tabata, Makoto, Adachi, Ichiro, Hamada, Nao, Hara, Koji, Iijima, Toru, Iwata, Shuichi, Kakuno, Hidekazu, Kawai, Hideyuki, Kumita, Tetsuro, Nishida, Shohei, Ogawa, Satoru, Sumiyoshi, Takayuki, Yoshida, Keisuke, and Yusa, Yosuke

Subjects
Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, Silica aerogel, Pin drying, FOS: Physical sciences, Particle detector, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Optics, Belle II, Nuclear Experiment (nucl-ex), Instrumentation, Nuclear Experiment, RICH, Cherenkov radiation, Hydrophobic silica, Physics, Cherenkovradiator, business.industry, Aerogel, DESY, Instrumentation and Detectors (physics.ins-det), Measuring instrument, Radiator (engine cooling), High Energy Physics::Experiment, business, Refractive index
Abstract

This paper presents recent progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter, which will be installed in the forward end cap of the Belle II detector. The proximity-focusing A-RICH system is especially designed to identify charged kaons and pions. The refractive index of the installed aerogel Cherenkov radiators is approximately 1.05, and we aim for a separation capability exceeding 4$\sigma $ at momenta up to 4 GeV/$c$. Large-area aerogel tiles (over 18 $\times $ 18 $\times $ 2 cm$^3$) were first fabricated in test productions by pin drying in addition to conventional methods. We proposed to fill the large end-cap region (area 3.5 m$^2$) with 124 water-jet-trimmed fan-shaped dual-layer-focusing aerogel combinations of different refractive indices (1.045 and 1.055). Guided by the test production results, we decided to manufacture aerogels by the conventional method and are currently proceeding with mass production. In an electron beam test undertaken at the DESY, we confirmed that the $K$/$\pi $ separation capability of a prototype A-RICH counter exceeded 4$\sigma $ at 4 GeV/$c$., Comment: To be published in Nucl. Instrum. Methods A,, 5 pages, 5 figures

Published
2014
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36. Evidence of $\mathrm{\Upsilon }\left(1S\right)\to J/\psi +{\chi }_{c1}$ and search for double-charmonium production in $\mathrm{\Upsilon }\left(1S\right)$ and $\mathrm{\Upsilon }\left(2S\right)$ decays

Author

Yang, S. D., Shen, C. P., Ayad, R., Shibata, T. -A., Shiu, J. -G., Shwartz, B., Sibidanov, A., Sohn, Y. -S., Sokolov, A., Staric, Marko, Steder, Michael, Sumiyoshi, T., Tamponi, U., Bakich, A. M., Tanida, K., Tatishvili, G., Teramoto, Y., Uchida, M., Uehara, S., Uglov, T., Unno, Y., Uno, S., Urquijo, P., Usov, Y., Bansal, V., Vahsen, S. E., Van Hulse, C., Vanhoefer, P., Varner, G., Vinokurova, A., Vorobyev, V., Vossen, A., Wagner, M. N., Wang, C. H., Wang, M. -Z., Behera, P., Wang, P., Wang, X. L., Watanabe, M., Watanabe, Y., Won, E., Yamaoka, J., Yashchenko, Sergey, Yook, Y., Yuan, C. Z., Zhang, Z. P., Bhuyan, B., Zhilich, V., Zhulanov, V., Belle Collaboration, Al Said, S., Bobrov, A., Danilov, M., Drutskoy, A., Dutta, K., Gaur, V., Hayasaka, K., Bozek, A., Kim, H. J., Kim, J. H., Kuzmin, A., Li, J., Li, Y., Li Gioi, L., Ritter, M., Schnell, G., Simon, F., Bračko, M., Browder, T. E., Červenkov, D., Chekelian, Vladimir, Ban, Y., Chen, A., Cheon, B. G., Chilikin, K., Chistov, R., Cho, K., Chobanova, V., Choi, S. -K., Choi, Y., Cinabro, D., Dalseno, J., Abdesselam, A., Dingfelder, J., Doležal, Z., Drásal, Z., Eidelman, S., Farhat, H., Fast, J. E., Ferber, Torben, Gabyshev, N., Ganguly, S., Garmash, A., Adachi, I., Gillard, R., Goh, Y. M., Golob, B., Haba, J., Hara, T., Hayashii, H., He, X. H., Hou, W. -S., Huschle, M., Iijima, T., Aihara, H., Inami, K., Ishikawa, A., Itoh, Ryosuke, Jaegle, I., Joffe, D., Joo, K. K., Julius, T., Kawasaki, T., Kim, D. Y., Kim, J. B., Arinstein, K., Kim, K. T., Kinoshita, K., Ko, B. R., Kodys, Peter, Korpar, Samo, Krizan, Peter, Krokovny, P., Kwon, Y. -J., Lange, Jens Sören, Libby, J., Asner, D. M., Liventsev, D., Lukin, P., Miyabayashi, K., Miyata, H., Moll, A., Mussa, R., Nakano, E., Nakao, Mikihiko, Nanut, T., Nisar, N. K., Aulchenko, V., Nishida, S., Okuno, S., Ostrowicz, Waclaw, Park, C. W., Park, H., Pedlar, T. K., Pestotnik, Rok, Petrič, M., Piilonen, L. E., Ribežl, E., Aushev, T., Rostomyan, Armine, Sakai, Y., Sandilya, S., Santelj, L., Sanuki, T., Schneider, O., Schwanda, C., Semmler, D., Senyo, K., and Shebalin, V.

Subjects
10.52 GeV-cms, +J%2Fpsi%283100%29+chi%2Fc1%283510%29%22">Upsilon(9460) --> J/psi(3100) chi/c1(3510), factorization [quantum chromodynamics], nonrelativistic [quantum chromodynamics], BELLE, annihilation [electron positron], branching ratio: upper limit [Upsilon(9460)], X(3940), branching ratio: upper limit [Upsilon(10020)], KEK-B, hadronic decay [upsilon mesons], High Energy Physics::Experiment, ddc:530, branching ratio: measured [Upsilon(9460)], experimental results
Abstract

Using data samples of $102×{10}^{6}$ $\mathrm{\Upsilon }\left(1S\right)$ and $158×{10}^{6}$ $\mathrm{\Upsilon }\left(2S\right)$ events collected with the Belle detector, a first experimental search has been made for double-charmonium production in the exclusive decays $\mathrm{\Upsilon }\left(1S,2S\right)\to J/\psi \left({\psi }^{\prime }\right)+X$, where $X={\eta }_{c}$, ${\chi }_{cJ}\left(J=0,1,2\right)$, ${\eta }_{c}\left(2S\right)$, $X\left(3940\right)$, and $X\left(4160\right)$. No significant signal is observed in the spectra of the mass recoiling against the reconstructed $J/\psi $ or ${\psi }^{\prime }$ except for the evidence of ${\chi }_{c1}$ production with a significance of $4.6\sigma $ for $\mathrm{\Upsilon }\left(1S\right)\to J/\psi +{\chi }_{c1}$. The measured branching fraction $\mathcal{B}\left(\mathrm{\Upsilon }\left(1S\right)\to J/\psi +{\chi }_{c1}\right)$ is $\left[3.90±1.21\left(\text{stat}\right)±0.23\left(\text{syst}\right)\right]×{10}^{-6}$. The 90% C.L. upper limits on the branching fractions of the other modes having a significance of less than $3\sigma $ are determined. These results are consistent with theoretical calculations using the nonrelativistic QCD factorization approach.

Published
2014

38. Silica Aerogel Radiator for Use in the A-RICH System Utilized in the Belle II Experiment

Author

田端, 誠, 足立, 一郎, 浜田, 尚, 原, 康二, 飯嶋, 徹, 岩田, 修一, 角野, 秀一, 河合, 秀幸, Korpar, Samo, Krizan, Peter, 汲田, 哲郎, 西田, 昌平, 小川, 了, Pestotnik, Rok, Santelj, Luka, Seljak, Andrej, 住吉, 孝行, Tahirovic, Elvedin, 吉田, 圭佑, 遊佐, 洋右, Tabata, Makoto, Adachi, Ichiro, Hamada, Nao, Hara, Koji, Iijima, Toru, Iwata, Shuichi, Kakuno, Hidekazu, Kawai, Hideyuki, Kumita, Tetsuro, Nishida, Shohei, Ogawa, Satoru, Sumiyoshi, Takayuki, Yoshida, Keisuke, Yusa, Yosuke, 田端, 誠, 足立, 一郎, 浜田, 尚, 原, 康二, 飯嶋, 徹, 岩田, 修一, 角野, 秀一, 河合, 秀幸, Korpar, Samo, Krizan, Peter, 汲田, 哲郎, 西田, 昌平, 小川, 了, Pestotnik, Rok, Santelj, Luka, Seljak, Andrej, 住吉, 孝行, Tahirovic, Elvedin, 吉田, 圭佑, 遊佐, 洋右, Tabata, Makoto, Adachi, Ichiro, Hamada, Nao, Hara, Koji, Iijima, Toru, Iwata, Shuichi, Kakuno, Hidekazu, Kawai, Hideyuki, Kumita, Tetsuro, Nishida, Shohei, Ogawa, Satoru, Sumiyoshi, Takayuki, Yoshida, Keisuke, and Yusa, Yosuke

Abstract

著者人数: 20名

Published
2015

39. Development of the readout ASIC for the 144ch HAPD for aerogel RICH

Author

西田, 昌平, 足立, 一郎, Dolenec, Rok, 池田, 博一, Korpar, Samo, 黒田, 英諒, 宮沢, 優一, 西澤, 勲, Pestotnik, Rok, 住吉, 孝行, 植木, 泰生, Nishida, Shohei, Adachi, Ichiro, Ikeda, Hirokazu, Kuroda, Eiryo, Miyazawa, Yuichi, Nishizawa, Isao, Sumiyoshi, Takayuki, Ueki, Yasuo, 西田, 昌平, 足立, 一郎, Dolenec, Rok, 池田, 博一, Korpar, Samo, 黒田, 英諒, 宮沢, 優一, 西澤, 勲, Pestotnik, Rok, 住吉, 孝行, 植木, 泰生, Nishida, Shohei, Adachi, Ichiro, Ikeda, Hirokazu, Kuroda, Eiryo, Miyazawa, Yuichi, Nishizawa, Isao, Sumiyoshi, Takayuki, and Ueki, Yasuo

Abstract

著者人数: 11名

Published
2015

41. Silica aerogel radiator for use in the A-RICH system utilized in the Belle II experiment

Author

Tabata, Makoto, primary, Adachi, Ichiro, additional, Hamada, Nao, additional, Hara, Koji, additional, Iijima, Toru, additional, Iwata, Shuichi, additional, Kakuno, Hidekazu, additional, Kawai, Hideyuki, additional, Korpar, Samo, additional, Križan, Peter, additional, Kumita, Tetsuro, additional, Nishida, Shohei, additional, Ogawa, Satoru, additional, Pestotnik, Rok, additional, Šantelj, Luka, additional, Seljak, Andrej, additional, Sumiyoshi, Takayuki, additional, Tahirović, Elvedin, additional, Yoshida, Keisuke, additional, and Yusa, Yosuke, additional

Published
2014
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46. Readout ASICs and Electronics for the 144-channel HAPDs for the Aerogel RICH at Belle II

Author

Korpar, Samo, Krizan, Peter, Pestotnik, Rok, Seljak, A., Nishida, Shohei, Adachi, Ichiro, Ikeda, Hirokazu, Hara, Kohji, Iijima, Toru, Iwata, Shuichi, Kuroda, Eiryo, Sumiyoshi, Takayuki, and Takagaki, H.

Subjects
Physics, business.industry, Physics::Instrumentation and Detectors, Detector, Photodetector, Aerogel, General Medicine, Physics and Astronomy(all), Application-specific integrated circuit, Radiator (engine cooling), Optoelectronics, High Energy Physics::Experiment, Electronics, business, Cherenkov radiation, Communication channel
Abstract

著者人数: 13名, 資料番号: SA1004448000

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47. Study of B ---> phi phi K Decays

Author

Abe, Kazuo, Shen, Y. T., Chen, K. F., Chang, P., Adachi, I., Aihara, H., Anipko, D., Arinstein, K., Aso, T., Aulchenko, V., Aushev, T., Aziz, T., Bahinipati, S., Bakich, Andrew M., Balagura, V., Ban, Y., Banerjee, S., Barberio, Elisabetta, Barbero, M., Bay, Aurelio, Bedny, I., Belous, K., Bhardwaj, V., Bitenc, Urban, Blyth, S., Bondar, Alexander E., Bozek, Andrzej, Bracko, Marko, Brodzicka, J., Browder, Thomas E., Chang, M. C., Chao, Y., Chen, A., Chen, W. T., Cheon, B. G., Chiang, C. C., Chistov, R., Cho, I. S., Choi, S. K., Choi, Y., Choi, Y. K., Cole, S., Dalseno, J., Danilov, M., Das, A., Dash, Manmohan, Dragic, J., Drutskoy, A., Eidelman, S., Epifanov, D., Fratina, Sasa, Fujii, H., Fujikawa, M., Gabyshev, Nikolay I., Garmash, A., Go, A., Gokhroo, G., Goldenzweig, P., Golob, Bostjan, Grosse Perdekamp, Matthias, Guler, H., Ha, H., Haba, Junji, Hara, K., Hara, T., Hasegawa, Y., Hastings, N. C., Hayasaka, Kiyoshi, Hayashii, Hisaki, Hazumi, Masashi, Heffernan, David, Higuchi, T., Hinz, L., Hokuue, T., Horii, Y., Hoshi, Y., Hoshina, K., Hou, S., Hou, George W. S., Hsiung, Y. B., Hyun, H. J., Igarashi, Y., Iijima, T., Ikado, K., Inami, Kenji, Ishikawa, Akimasa, Ishino, H., Itoh, K., Itoh, R., Iwabuchi, M., Iwasaki, Masako, Iwasaki, Yoshihito, Jacoby, C., Jones, M., Joshi, N. J., Kaga, M., Kah, D. H., Kaji, H., Kajiwara, S., Kakuno, H., Kang, J. H., Kapusta, P., Kataoka, S. U., Katayama, Nobu, Kawai, H., Kawasaki, T., Kibayashi, Atsuko, Kichimi, H., Kim, Hojeong, Kim, H. O., Kim, J. H., Kim, S. K., Kim, Y. J., Kinoshita, Kay, Korpar, S., Kozakai, Y., Krizan, Peter, Krokovny, P., Kumar, R., Kuo, Chen-Cheng, Kurihara, E., Kusaka, A., Kuzmin, A., Kwon, Youngjoon, Lange, J. S., Leder, G., Lee, J., Lee, J. S., Lee, M. J., Lee, S. E., Lesiak, T., Li, J., Limosani, A., Lin, S. W., Liu, Y., Liventsev, D., Macnaughton, J., Majumder, Gobinda, Mandl, F., Marlow, D., Matsumura, T., Matyja, A., Mconie, S., Medvedeva, T., Mikami, Y., Mitaroff, W., Miyabayashi, K., Miyake, H., Miyata, H., Miyazaki, Y., Mizuk, R., Mohapatra, Debabrata, Moloney, G. R., Mori, T., Mueller, J., Murakami, A., Nagamine, T., Nagasaka, Y., Nakahama, Y., Nakamura, I., Nakano, E., Nakao, M., Nakayama, H., Nakazawa, H., Natkaniec, Z., Neichi, K., Nishida, S., Nishio, Y., Nishizawa, I., Nitoh, O., Noguchi, S., Nozaki, Tadao, Ogawa, A., Ogawa, S., Ohshima, T., Okuno, S., Olsen, Stephen L., Ono, S., Ostrowicz, W., Ozaki, H., Pakhlov, P., Pakhlova, G., Palka, Henryk, Park, C. W., Park, H., Park, K. S., Parslow, N., Peak, L. S., Pernicka, M., Pestotnik, Rok, Peters, M., Piilonen, Leo E., Poluektov, A., Rozanska, M., Sahoo, H., Sarangi, T. R., Sasao, N., Satoyama, N., Sayeed, K., Schietinger, T., Schneider, Olivier, Schonmeier, P., Schumann, J., Schwanda, C., Schwartz, A. J., Seidl, Ralf-Christian, Sekiya, A., Senyo, K., Sevior, M. E., Shang, L., Shapkin, M., Shebalin, V., Shen, C. P., Shibuya, H., Shinomiya, S., Shiu, J. G., Shwartz, B., Sidorov, V., Singh, J. B., Sokolov, Andrei Valerevich, Somov, A., Stanic, Samo, Staric, M., Stypula, J., Sugiyama, Akira, Sumisawa, K., Sumiyoshi, T., Suzuki, S., Suzuki, S. Y., Tajima, O., Takasaki, F., Tamai, K., Tamura, N., Tanabe, K., Tanaka, M., Taniguchi, N., Taylor, Geoffrey N., Teramoto, Y., Tikhomirov, I., Trabelsi, K., Tse, Y. F., Tsuboyama, T., Uchida, K., Uchida, Y., Uehara, S., Ueno, K., Uglov, T., Unno, Y., Uno, S., Urquijo, Phillip, Ushiroda, Y., Usov, Y., Varner, Gary Sim, Kevin Varvell, Vervink, K., Villa, S., Vinokurova, A., Wang, C. C., Wang, Chung-Hsiang, Wang, J., Wang, M. Z., Wang, P., Wang, X. L., Watanabe, M., Watanabe, Y., Wedd, Robin, Wicht, J., Widhalm, L., Wiechczynski, J., Won, E., Yabsley, Bruce D., Yamaguchi, A., Yamamoto, Hitoshi, Yamaoka, M., Yamashita, Y., Yamauchi, M., Yuan, Chang-Zheng, Yusa, Y., Zhang, C. C., Zhang, L. M., Zhang, Z. P., Zhilich, V., Zhulanov, V., Ziegler, T., Zupanc, A., Zwahlen, N., and Zyukova, O.

48. Okrevanje silicijevih fotopomnoževalk po obsevanju z nevtroni

Author

Zajc, Gašper and Pestotnik, Rok

Subjects
thermal annealing, radiation damage, neutrons, silicijeve fotopomnoževalke, nevtroni, sevalne poškodbe, silicon photomultipliers, okrevanje
Abstract

Silicijeve fotopomnoževalke so polprevodniški detektorji svetlobe, sposobni zaznavati posamezne fotone. Sestavljene so iz mreže plazovnih fotodiod. So veliko manjše od običajnih fotopomnoževalk, neobčutljive na magnetno polje, imajo nižjo ceno izdelave ter delujejo pri manjših napetostih. Silicijeve fotopomnoževalke si želimo uporabljati tudi v sevalnih okoljih, kot so eksperimenti v fiziki visokih energij. Na področju vpliva sevalnih poškodb na detekcijo posameznih fotonov s silicijevimi fotopomnoževalkami še ni bilo narejenih veliko študij. V tej magistrski nalogi sem raziskoval vpliv obsevanja silicijevih fotopomnoževalk z nevtroni ter vpliv segrevanja silicijevih fotopomnoževalk na odpravo sevalnih poškodb. Raziskoval sem vpliv obsevanja na napetost praga ter na sposobnost zaznave posameznega fotona. Po obsevanju smo vsako celico segrevali pet zaporednih tednov pri temperaturi 100 °C ter po vsakem tednu spremljali njihovo okrevanje. Silicon photomultipliers are semiconductor light detectors, capable of detecting single photons. They are made of a matrix of single-photon avalanche diodes connected in parallel. They are a lot smaller than normal photomultiplier tubes, insensitive to magnetic field, have lower production prices and can be operated at lower voltages. There is a tendency for silicon photomultipliers to be used in radiation environments such as high energy physics experiments. In the field of the influence of radiation damage on the detection of individual photons with silicon photomultipliers, not many studies have been done yet. In this masters thesis, I investigated the influence of irradiation of silicon photomultipliers with neutrons and the influence of heating silicon photomultipliers on the elimination of radiation damage. I investigated the effect of radiation on the breakdown voltage and on the bility to detect an individual photon. After irradiation, each cell was heated at 100 °C for five consecutive weeks and monitored the recovery of silicon photomultipliers after each week.

Published
2020

49. Časovno digitalni pretvornik visoke ločljivosti na čipu Xilinx Zynq-7010

Author

Adamič, Michel and Pestotnik, Rok

Subjects
zakasnilna linija, pikosekundna ločljivost, Zynq, high-speed digital circuit design, tapped delay line, carry chain, prenosna logika, time-to-digital converter, picosecond resolution, časovno-digitalni pretvornik, hitra digitalna vezja, TDC, FPGA
Abstract

V sklopu tega magistrskega dela smo se lotili izdelave hitrega časovno-digitalnega pretvornika visoke ločljivosti na cenovno dostopni plošči Red Pitaya, ki temelji na zmogljivem polno programirljivem čipu Xilinx Zynq 7010. Časovno-digitalni pretvornik (TDC) je popolnoma digitalen in v celoti implementiran na programirljivem polju vrat (FPGA) v ravnokar omenjenem čipu, tako da za opravljanje meritev ne potrebujemo nobenih dodatnih zunanjih komponent. TDC je bil zasnovan po principu časovne interpolacije, kjer čas štejemo z uporabo sinhronega binarnega števca, za zelo natančno določitev časa prihoda med urinimi cikli pa skrbi integrirana zakasnilna linija. Posamezen kanal TDC je na voljo v obliki strojne komponente intelektualne lastnine (jedra IP) z vmesnikom AXI, kar je zelo priročno za gradnjo večkanalnih sistemov. Procesni sistem Zynq bere časovne značke aktivnih časovno-digitalnih pretvornikov in jih preko omrežja Ethernet pošilja odjemalcu, recimo osebnemu računalniku, kjer jih lahko ustrezno obdelamo in prikažemo v grafičnem uporabniškem vmesniku. V sklopu tega magisterija smo implementirali dva kanala TDC in ju podrobno okarakterizirali. Posamezen časovno-digitalni pretvornik teče na frekvenci 350~MHz in je ob mrtvem času $sim$14~ns sposoben vzorčiti do 70 milijonov značk na sekundo. Časovna ločljivost posameznega kanala dosega odličnih 11~ps in ostane zelo visoka tudi pri večjih časovnih intervalih, vsaj nekje do 100~ns. Izkazalo se je, da lahko tudi s povsem običajnimi signali s hitrostjo naraščanja 10~ns opravljamo meritve visoke ločljivosti, prav tako pa je meritev robustna na spremembe temperature. Izdelani TDC je zelo natančen in periodo zunanjega signala izmeri z relativno natančnostjo $10^{-5}$ v 60 stopinj širokem temperaturnem intervalu. Nazadnje smo inštrument preizkusili še v realistični postavitvi s pulznim laserjem in hitro silicijevo fotopomnoževalko (SiPM), kjer se je novi TDC odlično obnesel. Vse to dokazuje, da se da z izbiro primerne arhitekture in modernega čipa FPGA tudi na cenovno zelo dostopnih platformah, kot je Red Pitaya, implementirati izredno zmogljiv časovni merilni inštrument, ki je uporaben tako za študente kot profesionalne raziskovalce. This Master’s Thesis presents an implementation of a fast high-resolution time-to-digital converter (TDC) on the affordable Red Pitaya board, featuring a powerful all programmable Xilinx Zynq 7010 SoC. The design is fully digital, enabling the TDC to be implemented entirely within the Zynq FPGA, thus requiring no additional external components. The architecture of the TDC is based on the time interpolation technique which employs a coarse binary counter and a tapped delay line for fine time measurements between adjacent clock cycles. A TDC channel is packaged into an AXI-interfaced IP core, making it easy to build multichannel systems. Produced timestamps from active TDC channels are read by the Zynq processing system and sent via Ethernet to a client, for example a PC which can process and display them with a graphical user interface. A two-channel TDC system has been implemented and thoroughly characterized during this Thesis work. An individual channel runs at 350~MHz and has a dead time of $sim$14~ns, sampling up to 70 million timestamps per second. Its time resolution can reach an astounding 11~ps and remains very high even at larger time intervals of up to 100~ns. It turned out that high-resolution measurements can also be done with standard 10~ns rise time signals and with widely varying temperatures. The implemented TDC is very accurate and can measure the period of an externally applied signal with relative accuracy of $10^{-5}$ over a 60 degree temperature swing. Finally, the instrument was put to the test in a realistic setup with a pulsed laser and a fast silicon photomultiplier (SiPM), where the new TDC performed exceedingly well. This concludes that by choosing the right architecture and a modern FPGA, a very powerful time measurement instrument, useful both for students and professionals, can be implemented on perfectly affordable hardware platforms such as the Red Pitaya.

Published
2020

50. Calibration of aerogel ring-imaging Cherenkov detector in Belle II spectrometer

Author

Mrvar, Manca and Pestotnik, Rok

Subjects
Cherenkov photons, Ring-Imaging Cherenkov detector, hybrid avalanche photodetector, razlikovanje med nabitimi kaoni in pioni, fotoni Čerenkova, detektor obročev Čerenkova, calibration, identifikacija nabitih delcev, the charged kaon/pion separation, hibridni plazovni fotodetektor, umeritev, Detektor Belle II, The Belle II spectrometer, particle identification
Abstract

The Aerogel Ring-Imaging Cherenkov detector (ARICH) provides a charged particle identification in the endcap region of the Belle II spectrometer at the SuperKEKB asymmetric-energy $e^+ e^−$ collider in Tsukuba, Japan. The ARICH consists of a double layer aerogel radiator in a focusing configuration, an expansion volume and a plane of hybrid avalanche photodetectors. The methods of the calibration of the photodetectors and the readout electronics are discussed in the dissertation. The hardware calibration improved the separation of charged kaons and pions, which was studied with the $D^{*+} to D^0 (to K^- pi^+) pi_s^+$ decay. The identification algorithm was tested on the simulated sample. The simulation results show the efficiency of kaon identification above 90 percent at the pion misidentification probability of 5 percent. The developed procedure was also applied on the sample of collision data that was collected during the detector commissioning phase. Due to limited sample of the measured data, only the reconstructed $D^0 to K^- pi^+$ events were used for the performance studies. The results provide slightly decreased performance due to incomplete calibration of the tracking and particle identification system at the beginning of the operation. Detektor obročev Čerenkova z aerogelskim sevalcem (ARICH) je namenjen za identifikacijo nabitih delcev v smeri naprej detektorja Belle II ob asimetričnem trkalniku pozitronov in elektronov SuperKEKB, ki stoji v kraju Cukuba na Japonskem. ARICH sestavljajo dvoplastni sevalec iz aerogela, prazen prostor za razširjanje Čerenkovih fotonov in detektorska ravnina s hibridnimi plazovnimi fotodetektorji. V disertaciji je opisana umeritev detektorja, s katero izboljšamo ločevanje nabitih kaonov in pionov, ki jih neodvisno identificiramo pri razpadih $D^{*+} to D^0 (to K^- pi^+) pi_s^+$. Umeritvene metode in njihov vpliv na izboljšano ločevanje med kaoni in pioni smo preverili na vzorcu dogodkov, dobljenim z računalniško simulacijo. Rezultati simulacije so pokazali, da je z razvito metodo mogoče pravilno identificirati več kot 90 odstotkov kaonov ob zahtevi, da delež napačno identificiranih pionov ni večji od 5 odstotkov. Postopek smo uporabili tudi na vzorcu podatkov, ki smo jih zbrali pri prvih trkih na trkalniku SuperKEKB. Zaradi majhnega vzorca smo odziv detektorja preverili z uporabo rekonstruiranih razpadov $D^0 to K^- pi^+$, pri čemer je identifikacija delcev malenkost slabša zaradi nepopolne umeritve sledilnega ter identifikacijskega sistema ob začetku delovanja eksperimenta.

Published
2019

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