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SuperKEKB is an asymmetric energy electron positrion collider currently under commissioning in Japan. It aims to achieve a record high luminosity of $8×10^{35} \mathrm{cm}^{-2} \mathrm{s}^{-1}$, for which accurate control of $β^{*}_{\mathrm{y}}$ is needed. The advanced final focus system is also relevant for studies related to future linear colliders, which similarly need to achieve very small beam sizes. To work for SuperKEKB, the K modulation technique is generalized to allow known quadrupole fields between the modulated magnets and the interaction point. Initial measurements taken in HER agree with simulations, and show that K modulation is suitable for measuring the minimum of the $β$ function at the interaction point within 1%, however it is too uncertain to be used for measuring the displacement of the beam waist away from the interaction point. In addition, tune shift equations for a modulated quadrupole are derived without assuming a thin lens perturbation, giving a simple method to calculate the tune shift to second order in the quadrupole strength modulation.

SuperKEKB is an electron-positron circular collider upgraded from KEKB. To reach higher luminosity, values of beta are extremely small at Interaction Point. Although magnets in interaction region have a very strong focusing effect, they make a large disturbance to beams. Higher order multipoles and their skew components of magnetic fields of IR magnets are located at a very high beta section with pi/2 phase difference from IP. These multipoles can give critical effect to beam dynamics at interaction point and reduce luminosity on SuperKEKB design. In this study, we calculated beam dynamics for effect of skew components for multipole magnet, and estimated the influence on luminosity by them., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

We theoretically demonstrate for the first time that a single free electron in circular/spiral motion emits twisted photons carrying well defined orbital angular momentum along the axis of the electron circulation, in adding to spin angular momentum. We show that, when the electron velocity is relativistic, the radiation field contains harmonic components and the photons of l-th harmonic carry lhbar total angular momentum for each. This work indicates that twisted photons are naturally emitted by free electrons and more ubiquitous in laboratories and in nature than ever been thought.

Whenever we try to enhance the production yield, we have problems identifying the cause of invisible defects over the entire process, even more so for charge-coupled devices (CCD). This time, we utilized the Mahalanobis Taguchi System (MTS) method with several original techniques to identify the cause of failure in the wafer process. We calculated the historical data of CCDs process parameter and took several countermeasures. According to the results, we learned that the invisible defects corresponded to the contamination of organic matter and the front-end process's sensitivity.

A retrospective analysis was performed to evaluate the prognostic significance of peritoneal cytology in patients with endometrial carcinoma limited to the uterus. A total of 280 patients with surgically staged endometrial carcinoma that was histologically confined to the uterus were examined clinicopathologically. The median length of follow-up was 62 (range, 12-135) months. All patients underwent hysterectomy and salpingo-oophorectomy with selective lymphadenectomy, and only three patients received adjuvant postoperative therapy. No preoperative adjuvant therapy was employed. In all, 48 patients (17%) had positive peritoneal cytology. The 5-year survival rate among patients with positive or negative peritoneal cytology was 91 or 95%, respectively, showing no significant difference (log-rank, P=0.42). The disease-free survival rate at 36 months was 90% among patients with positive cytology, compared with that of 94% among patients with negative cytology, and the difference was not significant (log-rank, P=0.52). Multivariate proportional hazards model revealed only histologic grade to be an independent prognostic factor of survival (P=0.0003, 95% CI 3.02 - 40.27) among the factors analysed (age, peritoneal cytology, and depth of myometrial invasion). Multivariate analysis revealed that histologic grade (P=0.02, 95% CI 1.21-9.92) was also the only independent prognostic factor of disease-free survival. We concluded that the presence of positive peritoneal cytology is not an independent prognostic factor in patients with endometrial carcinoma confined to the uterus, and adjuvant therapy does not appear to be beneficial in these patients.

Okada S, Tsuda H, Ohmi K, Kasamatsu T, Yamada T, Tsunematsu R, Sumi M, Tokuuye K, Yoshikawa H, Hirohashi S. Immature glandular features in squamous cell carcinoma of the uterine cervix as an independent indicator of resistance to radiotherapy.The aim of this study was to evaluate the significance of “immature glandular features” in cervical squamous cell carcinoma (SCC) as an indicator of tumor radioresistance. Pretreatment biopsied tissue specimens of cervical SCC from 100 patients who were uniformly treated with radiotherapy alone were classified into clinically radioresistant (cR) and radiosensitive (cS) groups. Seven histologic parameters comprising glassy cells, signet ring cells, squamous differentiation, recognizable gland, nuclear atypia, stromal response, and mitotic counts were examined. Glassy cells and signet ring cells were regarded as “immature glandular features”. The correlation of these seven parameters with tumor response to radiotherapy and patient prognosis was analyzed by univariate and multivariate analyses. As objective indicators of glandular differentiation, alcian-blue staining and immunostaining of cytokeratins 7 and 20 were also performed. It was revealed that immature glandular features, absence of squamous differentiation, and low nuclear atypia were significant indicators of radioresistance of the tumor and of poorer patient prognosis. Combining those histological parameters, the present SCC cases were classified into 26 pathologically radioresistant (pR) and 74 radiosensitive (pS) groups. In the pR group, 54% (14 of 26) were clinically radioresistant, whereas 20% (15 of 74) of the pS group were clinically radioresistant (P = 0.002). The overall prognosis of the pR group was much poorer than that of the pS group (P < 0.0001). This correlation also held true in cases of identical stage and age. We could not show objectively glandular differentiation of “immature glandular features”. Nonetheless, the identification of “immature glandular features” was effective in predicting the radiotherapy resistance of cervical SCC and poorer patient prognosis.

Kasamatsu T, Hasegawa T, Tsuda H, Okada S, Sawada M, Yamada T, Tsunematsu R, Ohmi K, Mizuguchi K, Kawana T. Primary epithelioid sarcoma of the vulva.A case of a 31-year-old woman with epithelioid sarcoma of the vulva which metastasized to the regional lymph node 8 years after onset of the disease is reported here. The patient first noticed a painless subcutaneous mass of 5 mm in diameter in the right labium majus at age of 21. This was excised locally at age 23, but recurred 17 months later. Although local excision was again performed, the tumor recurred and continued to enlarge very slowly. At this stage, based on the pathology of both the initial and second tumors, the diagnosis was of a benign inflammatory process. However, local recurrence and inguinal lymph node swelling occurred at age 29, and biopsy was taken. The pathology report indicated benign granulomatous changes. The slides were reconsidered and re-interpreted as epithelioid sarcoma, whereupon radical vulvectomy was performed at age 31. Vulvar epithelioid sarcoma with inguinal lymph node metastasis was first diagnosed at that time. Epithelioid sarcoma of the vulva is an exceedingly rare tumor, and only 15 cases have been reported thus far in the literature. Early diagnosis and curative treatment of this tumor may be problematic for gynecologists because of its rarity and therefore little-known characteristic clinical behavior and histology. Radical vulvectomy or extensive local excision with inguinal lymphadenectomy at the time of diagnosis is recommended as the treatment of choice.

Infections with Shiga toxin (Stx)-producing Escherichia coli (STEC) cause microvascular endothelial cell damage, resulting in hemorrhagic colitis and hemolytic uremic syndrome. The prevention of endothelial cell damage is therefore a crucial step in overcoming this disorder. Here, we report that nitrobenzylthioinosine (NBT), a nucleoside transport inhibitor, has a protective effect against the cytotoxicity of Stxs in human microvascular endothelial cells (HMVECs). The relative viability of cells treated with 1.5-15 pM of Stx1 was reduced to 10-20% of that without Stx1. However, the viability of cells treated with NBT (10-100 microM) remained higher than 80%, even in the presence of Stx1. NBT also protected against Stx1 cytotoxicity in sodium butyrate-treated hypersensitive HMVECs. The protective effect of NBT against Stx cytotoxicity may be due to the depletion of ATP in the cells, thereby inhibiting the entry of Stx1.

During 2008 and 2009 dedicated beam experiments with crab cavities were performed in the KEKB. The goal was to measure the impact of crab-cavity radio frequency (rf ) noise on the beam quality. These experiments were performed as a validation of the crab-cavity beam dynamics models in view of the possible use of crab cavities in the upgrade of the CERN Large Hadron Collider (LHC). An unexpected strong beam-beam instability was observed during the course of the experiments as a kind of frequency response. Understanding this finding required extensive multiparticle and single particle simulations plus an extra experimental session to consolidate the observations. Published in PRST-AB 14:111003 (2011)

Data of the ηπ− system were obtained in the reaction π−p → ηπ−p at 6.3 GeV/c beam momentum. About 17 k events of ηπ− were collected in the mass range 0.8 ⩽ Mηπ- ⩽ 1.8 GeV/c2 and in the range of the momentum transfer squared 0.075 ⩽ |t′| ⩽ 0.60 (GeV/c)2. A large forward-backward asymmetry was observed around 1.3 GeV/c2 in the Gottfried-Jackson frame of the ηπ− system. A partial wave analysis of the data was performed. A peak of the D+ wave attributed to a2 (1320) is clearly seen. An enhancement is observed around 1.3 GeV/c2 in the P+ wave.

The electron-positron collider DAPhiNE, the Italian Phi factory, has been recently upgraded in order to implement an innovative collision scheme based on large crossing angle, small beam sizes at the crossing point, and compensation of beam-beam interaction by means of sextupole pairs creating a "crab-waist" configuration in the interaction region. Experimental tests of the novel scheme exhibited an increase by a factor of 3 in the peak luminosity of the collider with respect to the performances reached before the upgrade. In this Letter we present the new collision scheme, discuss its advantages, describe the hardware modifications realized for the upgrade, and report the results of the experimental tests carried out during commissioning of the machine in the new configuration and standard operation for the users.

Optics parameters such as betatron tunes, beta functions, and dispersions depend on momentum deviation. Such dependence is characterized by general chromaticity. General chromaticity can induce emittance growth and luminosity degradation in colliders. To investigate the influence of general chromaticity on beam dynamics, a symplectic map for chromaticity was implemented in the beam-beam codes and used in simulations at KEKB. A systematic investigation revealed that chromatic $X\mathrm{\text{\ensuremath{-}}}Y$ couplings can deteriorate the machine luminosity in the order of 10% with head-on colliding beams. The results of this study triggered the installation of skew sextupoles to KEKB rings for the purpose of correcting the chromatic $X\mathrm{\text{\ensuremath{-}}}Y$ couplings. Beam commissioning with skew-sextupole tuning knobs at KEKB has proved to be very successful; a new world's record luminosity of $2.1\ifmmode\times\else\texttimes\fi{}{10}^{34}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}\text{ }{\mathrm{s}}^{\ensuremath{-}1}$ was achieved with Belle taking data in June, 2009. In this paper, we discuss the approach of general chromaticity and present the results of simulations at KEKB.

A high-statistics experiment on the reaction π − p→ π + π − π 0 n at 8.06 GeV/ c has been performed using a spectrometer detecting both charged particles and gamma rays. A partial-wave analysis based on the isobar model has been carried out for π + π − π 0 data in the mass range between 0.86 and 1.50 GeV for four t ′ regions: 0.0–0.1, 0.1–0.25, 0.25–0.45 and 0.45–0.95 (GeV/ c 2 ). Two axial-vector resonances, a 1 (1260) and h 1 (1170), were observed in the analysis. The masses and widths of a 1 and h 1 were determined to be M (a 1 = 1121 ± 8 MeV, Λ (a 1 = 239± 11 MeV, M (h 1 = 1168±4 MeV and Λ (h 1 = 345±6 MeV, respectively, by fitting the Breit-Wigner formula to the partial wave amplitude. A fit including the Deck type background was also tried in each t ′ region. The results showed a small effect on these resonance parameters and were consistent with those obtained by the simple Breit-Wigner fitting.

A new superconducting vertical wiggler was installed in the 2.5 GeV KEK‐PF ring in Sept. 1989 and has been operated as a generator of a synchrotron radiation since Oct. 1989. Characteristics of the wiggler are reported here. The wiggler has five magnet poles with a maximum field strength of 5 T along the beam orbit. The wiggler is operated in a permanent current mode and consumes liquid helium of 0.12±0.02 l/h. An orbit distortion due to the decrease of the exciting current in the permanent current mode which comes from resistance of junctions between coils and PCSs is corrected by two normal steering magnets. The wiggler is operated continuously without supplying any current for a few weeks.

We have measured and corrected chromatic $X\mathrm{\text{\ensuremath{-}}}Y$ coupling at an interaction point to improve the luminosity of KEKB. We have measured the beam position of betatron oscillations induced by the kicker using turn-by-turn beam position monitors. A phase space structure reconstructed by the beam position provides us not only the Twiss parameters but also information regarding $X\mathrm{\text{\ensuremath{-}}}Y$ coupling. We have also determined chromatic $X\mathrm{\text{\ensuremath{-}}}Y$ coupling using the measured $X\mathrm{\text{\ensuremath{-}}}Y$ coupling at each momentum deviation from the designed beam energy. Skew sextupole magnets are used to correct the chromatic $X\mathrm{\text{\ensuremath{-}}}Y$ coupling.

Microwave instability in the low energy ring of KEKB was studied using a broadband impedance model. The model gave excellent descriptions of longitudinal dynamics for both positive and negative momentum compactions. Moreover, it predicted that the threshold of microwave instability was a factor of 2 lower than the machine nominal operating bunch current. The prediction was confirmed by a measurement using the Belle detector. Furthermore, we integrated the longitudinal wakefield into the beam-beam simulation and applied it to study the combined effects in KEKB. As a result, the beam-beam simulation became truly three dimensional with emittance growth in all three dimensions simultaneously as the beam currents increase. In addition, an observed mystery of asymmetry in the horizontal scan could also be explained by our simulations.

Experimental studies on the ωπ 0 and νπ − systems in the π − p reactions have been performed at KEK. The moment analysis of the ωπ 0 system shows a clear peak of b 1 0 (1235) in the IJ pc = 11 +− wave. In the 11 −− wave, no clear peak is seen. The properties of C(1480) with 11 −− and ϱ(1450) are discussed taking into account upper limits of their cross sections. The experiment on the νπ − system was planned to search for an exotic resonance with IJ pc = 11 −+ . The data taking run was finished and an analysis is under way.

An orbit feedback system around the interaction point (IP) has been developed and successfully employed at KEKB for more than 6 years. The purpose of the system is to maintain an optimum geometrical relationship of orbits of two beams at the IP and to prevent a luminosity degradation due to orbit drifts. The feedback system is based on orbit measurements around the IP rather than a direct measurement of the luminosity. Owing to the system, the luminosity degradation due to the orbit drifts is suppressed to around or less than 1%.

Crab cavities have been installed in the KEKB B-factory rings to compensate the crossing angle at the collision point and thus increase luminosity. The beam operation with crab crossing has been done since February 2007. This is the first experience with such cavities in colliders or storage rings. The crab cavities have been working without serious issues. While higher specific luminosity than the geometrical gain has been achieved, further study is necessary and under way to reach the prediction of simulation.

KEKB has been operating with crab cavities for the first time in the world. This paper represents beam operation with the crab crossing.

At KEKB, a dedicated machine experiment on crab crossing has been carried out for about 4.5 months. Some of the beam-beam effects observed with crab crossing, which include a beam lifetime issue, are discussed in comparison with those with a finite crossing angle of plusmn11 mrad.

We present the first evidence of the decay B-→τ-ντ, using 414fb-1 of data collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including systematics and measure the branching fraction to be B(B-→τ-ντ)=(1.79-0.49+0.56(stat) -0.51+0.46(syst))×10-4. This implies that fB=0.229-0.031+0.036(stat)-0. 037+0.034(syst)GeV and is the first direct measurement of this quantity. © 2006 The American Physical Society.

Recently, we have observed vertical betatron sidebands in the transverse beam spectra of positron bunches at the KEKB LER which are associated with the presence of electron clouds.[1] When the LER is operating in single-beam mode (no colliding bunches in the HER), these sidebands are sharply peaked. When the bunches are in collision for physics running, the sidebands are still present but are found to be smeared out. The bunch-by-bunch specific luminosity is lower for bunches with sidebands than for those without sidebands. In this paper, the behavior of the sidebands in collision and the effects on luminosity are discussed.

We have studied the parasitic long-range beam-beam effect at the KEKB by a strong-strong beam-beam simulation. Simulation result shows a parasitic long-range non-linear beam-beam effect change the contour diagram of the luminosity. The luminosity degradation is observed near the half integer tune due to the dynamic beta effect.

We calculate the impedance of the ceramic chamber inside of which is coated with TiN and outside of which is Cu shielded.

Crab crossing has been proposed to boost up the luminosity performance at KEKB. The luminosity is boosted up by removing x-z coupling due to the crossing angle. For a high beam-beam parameter (ξ > 0.05), linear couplings between degree of freedom induces symplectic diffusion, with the result that emittance growth and luminosity degradation arises. We have to care not only x − z coupling (crossing angle) but also x − y and y − z couplings. Chromaticity may be next order contribution of the luminosity degradation, External diffusion due to fast noises, for example kicker noise and phase jitter of cavities in crab crossing, could affect the luminosity performance. We present the tolerance for linear couplings, chromaticity and the fast noise in the crab crossing at KEKB.

BEPC will be upgraded into BEPCII, and the luminosity will be about 100 times higher. We developed a three dimensional strong-strong PIC code to study the beam-beam effects in BEPCII. The transportation through the arc is the same as that in Hirata’s weak-strong code. The beam-beam force is computed directly by solving the Poisson equation using the FACR method, and the boundary potential is computed by circular convolution. The finite bunch length effect is included by longitudinal slices. An interpolation scheme is used to reduce the required slice number in simulations. The standard message passing interface (MPI) is used to parallelize the code. The computing time increases linearly with (n + 1), where n is the slice number. The calculated luminosity of BEPCII at the design operating point is less than the design value. The best area in the tune space is near (0.505,0.57) according to the survey, where the degradation of luminosity can be improved.

Synchro-beta side band signal caused by electron cloud instability has been observed at KEK-B factory. The side-band appears above the threshold of beam size blow-up and disappears by exciting solenoid magnets which covers whole ring. The side-band is an evidence of strong head-tail instability caused by electron cloud. The side-band appears in tune spectrum with positive shift ν β + aν s (1 β − aν s (a > 0). We study the synchro-beta spectrum using a code, PEHTS, which simulates single bunch electron cloud instability.

Coupled bunch instability caused by electron cloud has been observed in the KEKB-LER. Time evolution of the instabilities just after the turning-off the transverse bunch feedback have been recorded with several solenoid-field conditions to suppress the blowup due to electron cloud. The mode spectra of the coupled-bunch instabilities have been compaired with the simulations of electrons moving in drift space, weak solenoid field and strong bending field.