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36 results on '"Masafumi Tawada"'

1. Excitation and Magnetic Field Performances of a Prototype REBCO Sextupole Coil at 4.2 K

Author

Masanori Kawai, Yasushi Arimoto, Masafumi Tawada, Kiyosumi Tsuchiya, Akihiro Kikuchi, Norihito Ohuchi, Xudong Wang, Ryuichi Ueki, Mika Masuzawa, Shinji Fujita, Zhanguo Zong, and Akio Terashima

Subjects
Materials science, Fabrication, Field (physics), business.industry, Condensed Matter Physics, Magnetic hysteresis, Electronic, Optical and Magnetic Materials, Magnetic field, law.invention, Conductor, Optics, Electromagnetic coil, law, Electrical and Electronic Engineering, business, Collider, Excitation
Abstract

A prototype REBa2Cu3Oy (REBCO) sextupole coil was designed and fabricated for the chromaticity correction of an asymmetric–energy collider, named SuperKEKB. The REBCO sextupole coil consists of the six two-layer-rectangular coils, which are wound with a 4-mm-wide coated conductor and impregnated with the epoxy resin. The inner bore radius and coil length are 75 mm and 200 mm, respectively. The designed sextupole field gradient is 200 T/m2 at an operating current of 250 A. We conducted a series of the experiments on the REBCO sextupole coil after the fabrication. In this paper, we present the experimental results of the excitation test and magnetic field measurement at 4.2 K.

Published
2020
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2. SuperKEKB operation using crab waist collision scheme

Author

Xiangyu Zhou, S. Nakamura, Michiru Nishiwaki, Takashi Mori, Toshiyuki Oki, Katsunobu Oide, H. Sugimura, Hiroshi Kaji, Masafumi Tawada, Hitomi Ikeda, Toshihiro Mimashi, R. Ueki, Yusuke Suetsugu, Shinji Terui, Demin Zhou, S. Enomoto, Yasushi Arimoto, Haruyo Koiso, G. Mitsuka, Zhanguo Zong, T. Miyajima, R. Yang, Akio Morita, Xudong Wang, Tatsuro Nakamura, Yoshihiro Funakoshi, Kyo Shibata, Kazuro Furukawa, Mitsuo Kikuchi, Kazuhito Ohmi, T. Yoshimoto, Kota Kodama, Hitoshi Fukuma, S. Yoshimoto, Hiroshi Sugimoto, Ken Watanabe, Takuya Kamitani, M. A. Rehman, Kazunori Akai, T. Kobayashi, Kazumi Egawa, Kota Nakanishi, Tetsuo Abe, Takuya Ishibashi, S. Ogasawara, Norihito Ohuchi, Mika Masuzawa, Yukiyoshi Ohnishi, Yuji Seimiya, Makoto Tobiyama, Fusashi Miyahara, T. Kawamoto, Naoko Iida, and S. Iwabuchi

Subjects
Scheme (programming language), Physics, Low emittance, Waist, Luminosity (scattering theory), Interaction point, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Collision, law.invention, Nuclear physics, symbols.namesake, law, symbols, Physics::Accelerator Physics, High Energy Physics::Experiment, Collider, computer, Beta function, computer.programming_language
Abstract

SuperKEKB is an electron–positron asymmetric-energy double-ring collider, which was built in Japan. It has been operated to explore new phenomena in B-meson decays. Hence, extremely higher luminosity is required. A collision scheme of low emittance with a large Piwinski angle called a “nano-beam scheme” has been adopted to achieve higher luminosity by squeezing the vertical beta function at the interaction point to be smaller than the bunch length. A “crab waist collision scheme” proposed by P. Raimondi et al. has also been adopted to improve the luminosity performance. The article presents an overview of the operation of the nano-beam and crab waist collision schemes at SuperKEKB.

Published
2021
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3. Prototype HTS Sextupole Magnet for SuperKEKB Interaction Region

Author

Masanori Daibo, Yasushi Arimoto, Yasuhiro Iijima, M. Masuzawa, Xudong Wang, Kiyosumi Tsuchiya, Norihito Ohuchi, Masafumi Tawada, Akio Terashima, Shinji Fujita, and Akihiro Kikuchi

Subjects
Materials science, Fabrication, business.industry, Superconducting magnet, Condensed Matter Physics, 01 natural sciences, Sextupole magnet, Electronic, Optical and Magnetic Materials, Conductor, Electromagnetic coil, Magnet, 0103 physical sciences, Electromagnetic shielding, Optoelectronics, Electrical and Electronic Engineering, 010306 general physics, business, Electrical conductor
Abstract

A prototype high-temperature superconductor (HTS) sextupole magnet for the SuperKEKB Interaction Region was fabricated and tested in order to gain experience in the fabrication of HTS magnets as well as to understand their characteristics. The designed field strength of the sextupole magnet is 200 T/m2 at 30 K. The coil of the magnet has an inner radius of 75 mm and a length of 200 mm. Furthermore, the magnet consists of six rectangular coils wound with a REBa2Cu3O7-x (REBCO) coated conductor, which is 4 mm wide and was impregnated with epoxy resin. After fabrication, the magnet was tested in LN2 and it was confirmed that the magnet had been fabricated with no degradation of the conductor properties. In this paper, we briefly present the design and fabrication of the magnet, and the test results at 77 K including the properties of the magnetic field.

Published
2019
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4. Critical current measurement of commercial REBCO conductors at 4.2 K

Author

Tomoaki Takao, Xudong Wang, M. Uchida, Akihiro Kikuchi, A. Terashima, Shinji Fujita, Masafumi Tawada, M. Masuzawa, Kiyosumi Tsuchiya, Norihito Ohuchi, and K. Norimoto

Subjects
010302 applied physics, Superconductivity, Large Hadron Collider, Materials science, General Physics and Astronomy, 01 natural sciences, Engineering physics, Future Circular Collider, Conductor, Nuclear magnetic resonance, Conceptual design, Dipole magnet, Magnet, 0103 physical sciences, General Materials Science, 010306 general physics, Electrical conductor
Abstract

REBCO coated conductors are now available from several industrial manufacturers and are expected to be promising conductors for high-field-magnet applications. Using these conductors, the development of solenoids capable of generating high magnetic fields of 20–30 T is ongoing in major high-field laboratories in the world. In addition, CERN recently launched a conceptual design study for the Future Circular Collider, in which a 20-T dipole magnet is listed as a candidate for the bending magnet of the main ring. However, there has been limited research published on the electrical transport properties of commercially available REBCO conductors in a high-field, low-temperature environment. For magnet designers, the transport properties are of the highest importance in choosing a suitable conductor, and the data form the bases for high-field magnet development. Therefore, in this work, a new sample holder, which allows the measurements of full-width conductors to be carried out relatively easily, was developed, and the transport properties of commercial REBCO conductors from seven manufacturers (AMSC, Fujikura, Shanghai Superconductor, SuNAM, SuperOx, SuperPower, and SWCC Showa) were investigated at 4.2 K in perpendicular fields of up to 18 T. The results show that the I c values at 4.2 K clearly vary to some extent among these commercial conductors and the higher-current 4-mm-wide conductors have I c values in the range of 230–305 A at 18 T and in the range of 320–424 A at 12 T.

Published
2017
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5. Development of HTS Sextupole Magnet for SuperKEKB Interaction Region

Author

Shinji Fujita, Zhanguo Zong, Masanori Daibo, Xudong Wang, Michinaka Sugano, Masafumi Tawada, Kiyosumi Tsuchiya, Yasuhiro Iijima, Norihito Ohuchi, A. Terashima, M. Masuzawa, Akihiro Kikuchi, and Yasushi Arimoto

Subjects
Physics, Luminosity (scattering theory), Interaction point, 010308 nuclear & particles physics, business.industry, Skew, Superconducting magnet, Condensed Matter Physics, 01 natural sciences, Sextupole magnet, Electronic, Optical and Magnetic Materials, KEKB, Optics, Nuclear magnetic resonance, Electromagnetic coil, Magnet, 0103 physical sciences, Physics::Accelerator Physics, Electrical and Electronic Engineering, 010306 general physics, business
Abstract

The SuperKEKB project underway at KEK will increase the KEKB luminosity by 40 times using nanobeam-interaction-region focusing optics. To achieve this high luminosity, the chromaticity correction of the collision beams is crucial; thus, special sextupole magnets, which can simultaneously produce normal and skew sextupole fields, are required in the straight sections around the interaction point. As a candidate for the sextupole, a cryocooled high-temperature superconducting magnet was proposed; development has begun. Here, the basic magnet design and the results of a small coil test are presented. The test studied the quench characteristics of the REBCO-impregnated coil.

Published
2016
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6. Design and Construction of the Final Focus Quadrupole R&D Magnet for Super-KEKB

Author

M. Iwasaki, Masafumi Tawada, Norio Higashi, Zhanguo Zong, Norihito Ohuchi, and Kiyosumi Tsuchiya

Subjects
Physics, Condensed matter physics, Superconducting magnet, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, law.invention, Nuclear physics, KEKB, Dipole magnet, law, Magnet, Quadrupole, Physics::Accelerator Physics, High Energy Physics::Experiment, Electrical and Electronic Engineering, Quadrupole magnet, Collider, Beam (structure)
Abstract

For upgrading the electron-positron collider KEKB, the final focusing magnet system in the beam interaction region has been studied. The designed magnet system consists of five superconducting and three permanent quadrupole magnets. A superconducting quadrupole magnet has been constructed as the R&D of this system. In this paper, design and construction of this R&D magnet are reported.

Published
2011
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7. Commissioning of KEKB

Author

Minoru Yoshida, Shigenori Hiramatsu, E. Perevedentsev, Shigeki Kato, Katsunobu Oide, Naoko Iida, Eiji Kikutani, Tatsuro Nakamura, Masafumi Tawada, Toshihiro Matsumoto, Mitsuo Kikuchi, Y. Wu, Masaaki Suetake, Kazuhito Ohmi, S. Uno, Noboru Yamamoto, Tsuyoshi Suwada, J. Haba, Toshiyuki Mitsuhashi, Takuya Kamitani, S. Yoshimoto, S. Kamada, Atsushi Enomoto, Kenji Hosoyama, Kazunori Akai, Shin-ichi Kurokawa, Kazuro Furukawa, Hitomi Ikeda, Yukiyoshi Ohnishi, Frank Zimmermann, N. Akasaka, J.W. Flanagan, Makoto Tobiyama, Yujiro Ogawa, Yoshihiro Funakoshi, Mika Masuzawa, Norihito Ohuchi, T. Ieiri, Satoshi Ohsawa, Masakazu Yoshioka, H. Fukuma, Toshihiro Mimashi, Yusuke Suetsugu, Haruyo Koiso, Masaki Tejima, Kotaro Satoh, and Takaaki Furuya

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Luminosity (scattering theory), KEKB, Detector, Beam instability, Beam emittance, Instrumentation, B-factory
Abstract

KEKB has been operated since December, 1998, to deliver BB pairs for a physics detector. In this paper,we describe the commissioning procedure of KEKB.

Published
2003
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8. The interaction region of KEKB

Author

Yoshikazu Yamada, Toshiyuki Ozaki, Minoru Yoshida, Kotaro Satoh, H. Nakayama, Masakazu Yoshioka, Ken-ichi Kanazawa, N. Toge, Masafumi Tawada, Norihito Ohuchi, Kiyosumi Tsuchiya, Ryuhei Sugahara, and Toru Ogitsu

Subjects
Physics, Nuclear and High Energy Physics, Luminosity (scattering theory), Interaction point, Superconducting magnet, Electron, law.invention, Nuclear physics, KEKB, law, Physics::Accelerator Physics, High Energy Physics::Experiment, Quadrupole magnet, Collider, Instrumentation, Storage ring
Abstract

An asymmetric-energy collider of 8 GeV electrons and 3.5 GeV positrons, KEKB, has been operating at KEK since 1998. On July 9, 2001 it achieved the highest record of luminosity, 4.5×10 33 cm −2 s −1 . This paper describes the interaction region (IR) extending about 8 m from the interaction point (IP) along each beam direction. The main machine components in the IR are focusing quadrupole magnets, compensation solenoids, and vacuum chambers, which are positioned on movable stages. They are designed to focus both beams into collisions with a finite angle crossing.

Published
2003
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9. Compact 8-lead unit for the SC correction coils of the SuperKEKB IR magnet system

Author

Zhanguo Zong, Masafumi Tawada, Narihito Ohuchi, Kiyosumi Tsuchiya, Norio Higashi, M. Iwasaki, and Hiroshi Yamaoka

Subjects
Engineering, business.industry, Electrical engineering, Mechanical engineering, chemistry.chemical_element, Finite element method, Brass, Material selection, chemistry, Magnet, visual_art, Thermal, visual_art.visual_art_medium, Transient (oscillation), Current (fluid), business, Helium
Abstract

In the proposed SuperKEKB interaction region (IR) magnet system 40superconducting (SC) correction coils are designed to perform some specific functions withcurrent of about 50 A. To energize these coils, 80 current leads will be mounted in thecryostats where the stringent spatial constraint and the cryogenic operation require acompact and optimum design. We propose a compact unit to integrate 8 helium vaporcooled leads (4 pairs). The 8 leads are made of brass and consist of two structures for thetransported current and helium vapor, which are designed and simulated by finite elementmodel (FEM). This paper will introduce the material selection and structure details. To equalize the temperature profiles of the individual leads under the different currents and helium flows, some copper blocks are placed between leads. In the cold test, the 8 leadswere operated in the nominal mode and responded safely to some transient situation. This paper will present the thermal and electrical comparison between the experimental resultsand numerical calculation.

Published
2012
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10. Orbit feedback system for maintaining an optimum beam collision

Author

Haruyo Koiso, Masaki Tejima, K. Ohmi, J.W. Flanagan, Mika Masuzawa, Makoto Tobiyama, T. Ieiri, Y. Funakoshi, Katsunobu Oide, and Masafumi Tawada

Subjects
Physics, Nuclear and High Energy Physics, Physics and Astronomy (miscellaneous), business.industry, Astrophysics::High Energy Astrophysical Phenomena, Surfaces and Interfaces, Collision, Optics, Astrophysics::Solar and Stellar Astrophysics, lcsh:QC770-798, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Astrophysics::Earth and Planetary Astrophysics, Orbit (control theory), business, Beam (structure)
Abstract

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%.

Published
2007

11. Status of R&D efforts toward the ERL-based future light source in Japan

Author

Nobuhiro Kikuzawa, Eiji Kako, Masanori Satoh, M. Tadano, S. Yamamoto, H. Tomizawa, Shinichi Sasaki, Shigeki Fukuda, Makoto Tobiyama, Shigenori Hiramatsu, Hiroshi Kawata, Kenji Hosoyama, Isao Ito, Masaaki Izawa, Toshiyuki Mitsuhashi, Satoshi Ohsawa, Takeshi Takahashi, K. Shinoe, Kimichika Tsuchiya, Atsushi Enomoto, T. Shishido, Eisuke Minehara, S. Sakanaka, T. Agoh, A. Mochihashi, H. Kudoh, Tsuyoshi Suwada, Kazuro Furukawa, Tohru Honda, Tsukasa Miyajima, Takashi Obina, Masao Kuriki, K. Satoh, Nobuyuki Nishimori, Masafumi Tawada, Kentaro Harada, Yukinori Kobayashi, T. Shibuya, Ryoji Nagai, H. Iijima, Mitsuo Kikuchi, Masahiro Katoh, Ryoichi Hajima, Takashi Naito, Toshiyuki Ozaki, Hiroyuki Takaki, Takaaki Furuya, Shinya Nagahashi, Kensei Umemori, T. Kasuga, Kaiichi Haga, Hirofumi Hanaki, A. Ishii, Masaru Sawamura, Tatsuro Shioya, Takashi Uchiyama, Masaaki Ono, Yasunori Tanimoto, M. Shimada, Shuichi Noguchi, H. Sasaki, Hiroshi Sakai, Takashi Nogami, and Norio Nakamura

Subjects
Nuclear physics, Physics, Light source, Synchrotron light source, Engineering physics, Energy recovery linac
Abstract

The energy recovery linac is a very promising synchrotron light source in future. We are contemplating to realize a ERL_based next generation light source in Japan, under a collaboration between KEK, JAEA, ISSP, and other SR institutes. To this end, we started R&D efforts on its key technologies, including a low-emittance photocathode gun and superconducting cavities. We also plan to assemble these technologies into a small test ERL, and to demonstrate their operations. We report our R&D status.

Published
2007
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12. Beam-Beam Simulation Study with Parasitic Crossing Effect at KEKB

Author

Y. Funakoshi, Masafumi Tawada, and K. Ohmi

Subjects
Physics, Luminosity (scattering theory), business.industry, Electron, Contour diagram, Computational physics, KEKB, Optics, Beta (plasma physics), Physics::Accelerator Physics, High Energy Physics::Experiment, Half-integer, business, Beam (structure)
Abstract

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.

Published
2006
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13. Recent Progress at KEKB

Author

Kiyokazu Ebihara, Masaaki Ono, Kazuro Furukawa, Hitomi Ikeda, Mitsuo Kikuchi, Yasuchika Yamamoto, Noboru Yamamoto, Tatsuro Nakamura, J. Haba, Shigeki Kato, Takashi Sugimura, Kazuhito Ohmi, S. Uno, Naoko Iida, Mika Masuzawa, Shigenori Hiramatsu, Haruyo Koiso, Masaki Tejima, Eiji Kikutani, H. Nakayama, K. Akai, N. Tokuda, Makoto Tobiyama, Miho Shimada, Takuya Kamitani, Tsuyoshi Suwada, Atsushi Enomoto, Takaaki Furuya, T. Ieiri, Katsunobu Oide, Samo Stanič, Yukiyoshi Ohnishi, Masafumi Tawada, Tatsuya Kageyama, Frank Zimmermann, J.W. Flanagan, Yoshiharu Yano, Y. Funakoshi, Yujiro Ogawa, S. Uehara, M. Yoshida, Norihito Ohuchi, Hitoshi Fukuma, Masaaki Suetake, Ma. Yoshida, Toshihiro Mimashi, Yusuke Suetsugu, A. Morita, K. Yokoyama, S. Yoshimoto, Kazumi Egawa, and S. Kamada

Subjects
Physics, Bellows, KEKB, business.industry, Electrical engineering, Superconducting magnet, business
Abstract

We summarize the machine operation of KEKB during past one year focusing on progress for this period.

Published
2006
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14. POP Experiment of Laser Stripping via a Broad Stark State Using BNL 200MeV H− Beams

Author

Toshihiro Mimashi, P. Cameron, K. Takayama, T. Suzuki, R. Connoly, K. Satoh, John Ritter, Masafumi Tawada, J. Alessi, A. Hershcovitch, Y.Y. Lee, H. Nakayama, I. Yamane, M. Blaskiewicz, J. Wei, V. LoDestro, and D. Raparia

Subjects
Physics, symbols.namesake, Stripping (chemistry), Stark effect, Beamline, law, symbols, Atomic physics, Laser, Linear particle accelerator, law.invention
Abstract

Present status of the project of the POP (proof of principle) experiment of laser stripping using BNL 200MeV H− is presented. First, the principle of the laser stripping via a broad Stark state and the role of the broad Stark state are introduced. Then, the scheme of the POP experiment using 200MeV H− is given. Then, the concrete plan of experimental setup in the REF beam line of the BNL 200MeV H− Linac and present status of construction are given.

Published
2005
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15. Luminosity limit due to the beam-beam interactions with or without crossing angle

Author

S. Kamada, Yunhai Cai, Kazuhito Ohmi, Ji Qiang, Katsunobu Oide, and Masafumi Tawada

Subjects
Physics, Nuclear and High Energy Physics, Luminosity (scattering theory), Physics and Astronomy (miscellaneous), business.industry, Astrophysics::High Energy Astrophysical Phenomena, Particle accelerator, Surfaces and Interfaces, Astrophysics::Cosmology and Extragalactic Astrophysics, Collision, law.invention, Computational physics, Aquatic organisms, Optics, KEKB, law, Limit (music), Physics::Accelerator Physics, lcsh:QC770-798, High Energy Physics::Experiment, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, business, Beam (structure)
Abstract

In recent high luminosity colliders, the finite crossing angle scheme becomes popular to gain the luminosity with multibunch or long bunch operation. Success of the KEKB factory showed that the finite crossing angle scheme has no problem achieving beam-beam parameters up to 0.05. We have studied the beam-beam interactions with and without crossing angle toward higher luminosity. We discuss how the crossing angle affects the beam-beam parameter and luminosity in the present KEKB using computer simulations. The simulations showed that crab cavities, which realize the head-on collision effectively, can be expected to double the luminosity.

Published
2004

16. Beam-Beam Limit ine+e−Circular Colliders

Author

K. Ohmi, Katsunobu Oide, Masafumi Tawada, Ji Qiang, Yunhai Cai, and S. Kamada

Subjects
Physics, education.field_of_study, Luminosity (scattering theory), Population, General Physics and Astronomy, B-factory, Nuclear physics, Quantum mechanics, Physics::Accelerator Physics, High Energy Physics::Experiment, Limit (mathematics), education, Simulation methods, Beam (structure)
Abstract

Beam-beam effects limit the luminosity of circular colliders. Once the bunch population exceeds a threshold, the luminosity increases at a slower rate. This phenomenon is called the beam-beam limit. Onset of the beam-beam limit has been analyzed with various simulation methods based on the weak-strong and strong-strong models. We have observed that an incoherent phenomenon is mainly concerned in the beam-beam limit. The simulation have shown that equilibrium distributions of the two colliding beams are distorted from Gaussians when the luminosity is limited. The beam-beam limit is estimated to be $\ensuremath{\xi}\ensuremath{\sim}0.1$ for a B factory with damping time of several thousand turns.

Published
2004
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17. Study of beam-beam interactions with/without crossing angle

Author

K. Ohmi, Katsunobu Oide, and Masafumi Tawada

Subjects
Physics, Nuclear physics, Particle physics, Beam diameter, KEKB, Physics::Accelerator Physics, High Energy Physics::Experiment, M squared, Astrophysics::Cosmology and Extragalactic Astrophysics, Laser beam quality, Particle beam, Beam parameter product, B-factory
Abstract

In recent high luminosity colliders, the finite crossing angle scheme becomes popular to gain the multiplicity of luminosity with multi-bunch or long bunch operation. Success of KEKB showed that it was no problem to achieve the beam-beam. parameter up to 0.05. We have studied the beam-beam interactions with/without crossing angle toward higher luminosity. We discuss how the crossing angle affects the beam-beam parameter and luminosity in the present KEK B factory (KEKB) using computer simulations.

Published
2004
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18. Observation of a Narrow Charmoniumlike State in ExclusiveB±→K±π+π−J/ψDecays

Author

Hiroyuki Sagawa, Katsunobu Oide, H. Yanai, Kazuo Abe, B. D. Yabsley, T. Hara, Y. Asano, S. Okuno, M. Yoshida, T. Abe, T. E. Browder, T. Aushev, K. Ohmi, Yong Ban, Takashi Nakamura, Y. Teramoto, I. Adachi, M. Starič, T. Okabe, M. Nakao, M. Danilov, A. Ishikawa, T. Sumiyoshi, T. Nakadaira, D. Mohapatra, T. Nozaki, F. Takasaki, P. Križan, H. J. Kim, N. Parslow, Norihito Ohuchi, O. Nitoh, A. M. Bakich, Z. Natkaniec, T. Ohshima, A. Satpathy, Yasuhiko Yamada, P. Chang, M. Iwasaki, B. Golob, O. Schneider, G. Leder, K. F. Chen, Y. Unno, Jung-Hyun Kim, Masafumi Tawada, F. Mandl, A. J. Schwartz, S. Y. Suzuki, Hyunwoo Kim, A. Bozek, K. Tamai, S. Uehara, M. E. Sevior, S. L. Olsen, N. Katayama, N. C. Hastings, Y. Hoshi, T. Iijima, Hiroaki Aihara, G. R. Moloney, Rolf Seuster, Suyong Choi, A. Drutskoy, J. H. Kang, Tetsuo Shidara, N. Gabyshev, C. C. Zhang, Y. Chao, H. Miyake, Toshihiro Mimashi, W. Ostrowicz, M. Satapathy, H. Shibuya, L. Hinz, S. Nishida, Y. Sakai, Akira Sugiyama, Zhenyu Zhang, Shinichiro Michizono, V.A. Sidorov, D. Žontar, A. Bondar, K. Ueno, S. Korpar, V. Eiges, Masashi Hazumi, Jolanta Brodzicka, H. K. Park, Y. Yamashita, L. Y. Dong, T. R. Sarangi, H. Palka, S. Semenov, L. E. Piilonen, E. Won, K. Trabelsi, Kazuro Furukawa, J. G. Wang, Daniel Robert Marlow, W. A. Mitaroff, Eiji Kikutani, Seong Keun Kim, C. Hagner, Young-Il Choi, Semen Eidelman, Y. Watanabe, K. Miyabayashi, H. Kichimi, Gobinda Majumder, K. Inami, T. J. Gershon, A. Yamaguchi, T. Tsukamoto, T. Nagamine, Yukiyoshi Ohnishi, S. W. Lin, H. C. Huang, P. Krokovny, T. Lesiak, R. Chistov, K. Senyo, N. Tamura, W. S. Hou, T. Kawasaki, S. Stanič, K. Kinoshita, S. Saitoh, S. Ogawa, Byung Gu Cheon, J.W. Flanagan, C. C. Wang, D. Liventsev, H. Kawai, B. Shwartz, M. Akemoto, Chikara Fukunaga, M. Akatsu, C. H. Wang, G. N. Taylor, J. Ying, J. S. Lange, Y. B. Hsiung, Yasushi Nagasaka, G. S. Varner, S. Uno, R. Itoh, Tsukasa Aso, R. Guo, H. Hayashii, J. MacNaughton, S. U. Kataoka, Patrick Koppenburg, K. Akai, Kevin Varvell, Heyoung Yang, Haruyo Koiso, T. Matsumoto, Byoung Sup Ahn, Y. Iwasaki, T. Tomura, H. Ozaki, S. H. Lee, V.M. Aulchenko, S. Banerjee, Y. Ogawa, F. Handa, Y. Choi, H. Guler, A.S. Kuzmin, N. Soni, Suneel Kumar, M. Bračko, and M. H. Tanaka

Subjects
Physics, Particle physics, Electron–positron annihilation, General Physics and Astronomy, Resonance, law.invention, Nuclear physics, KEKB, law, Mass spectrum, High Energy Physics::Experiment, Tetraquark, Z(4430), Collider, X(3872)
Abstract

We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of 3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M(D0)+M(D(*0)) mass threshold. The results are based on an analysis of 152M B-Bmacr; events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma.

Published
2003
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19. Measurements of the $D_{sJ}$ resonance properties

Author

G. R. Moloney, Mika Masuzawa, S. Uehara, Patrick Koppenburg, G. Leder, Y. Iwasaki, Y. J. Kwon, Gobinda Majumder, Hiroyuki Iwasaki, H. Palka, L. E. Piilonen, N. Katayama, T. Aushev, Masashi Hazumi, Norihito Ohuchi, Z. Natkaniec, R. Kulasiri, F. Mandl, M. H. Tanaka, T. Tsukamoto, M. E. Sevior, Hiroyuki Sagawa, W. Ostrowicz, S. Bahinipati, T. Matsumoto, T. Iijima, H. Miyata, Y. Hoshi, Y. Sakai, B. Golob, O. Schneider, R. Chistov, J. Ying, V.A. Sidorov, M. Yamauchi, D. Žontar, K. Trabelsi, P. Krokovny, Kazuro Furukawa, T. Sumiyoshi, H. J. Kim, A. Garmash, H. Park, Y. Yamashita, Y. Mikami, K. Ohmi, J. MacNaughton, W. S. Hou, Eiji Kikutani, H. Kawai, Heyoung Yang, Byung Gu Cheon, O. Nitoh, K. Senyo, Jung-Hyun Kim, K. S. Park, T. Nagamine, Yasushi Nagasaka, T. Hokuue, H. C. Huang, N. Kawamura, T. Kawasaki, S. Stanič, M. Iwasaki, N. Parslow, B. Shwartz, Chikara Fukunaga, A. Matyja, S. L. Olsen, Hiroaki Aihara, K. Inami, Ryuhei Sugahara, J. Dragic, Y. Chao, D. Liventsev, Yasuhiko Yamada, H. Shibuya, Tetsuo Shidara, Zhenyu Zhang, Toshihiro Mimashi, A. Bondar, Y. Watanabe, V. Eiges, A. Sugi, H. Kichimi, I. Bizjak, G. S. Varner, H. Yanai, M. Bračko, L. Y. Dong, Hirokazu Ikeda, S. K. Choi, C. W. Park, Tsukasa Aso, T. Abe, T. Tsuboyama, T. Lesiak, S. Uno, C. Schwanda, K. Kinoshita, S. Saitoh, S. Ogawa, T. J. Gershon, Kazuo Abe, B. D. Yabsley, T. Hara, Hitoshi Yamamoto, Y. Asano, P. Kapusta, Katsunobu Oide, M. Akemoto, S. Okuno, A. M. Bakich, T. Ohshima, E. Nakano, A. Chuvikov, M. Yoshida, S. Y. Suzuki, N. Gabyshev, I. Higuchi, A. Yamaguchi, K. Sumisawa, Jasvinder A. Singh, S. W. Lin, L. Hinz, M. Nakao, Y. Teramoto, Masafumi Tawada, T. Okabe, H. Hayashii, H. Ozaki, V.N. Zhilich, S. H. Lee, T. Tomura, J. H. Kang, S. Semenov, W. A. Mitaroff, Young-Il Choi, N. Soni, A. Ishikawa, A. Bay, Y. Ban, T. Nozaki, F. Takasaki, P. Križan, M. Starič, J. S. Kang, H. Nakazawa, G. Gokhroo, Y. Ogawa, Y. Yusa, S. Eidelman, A. J. Schwartz, F. Handa, S. Nishida, Y. Choi, A.S. Kuzmin, T. E. Browder, Takashi Nakamura, M. Danilov, P. Pakhlov, and A. Bozek

Subjects
Physics, Crystallography, High Energy Physics - Experiment (hep-ex), Radiative decay, General Physics and Astronomy, Resonance, FOS: Physical sciences, High Energy Physics::Experiment, Continuum (set theory), Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report measurements of the properties of the $D_{sJ}^+(2317)$ and $D_{sJ}^+(2457)$ resonances produced in continuum $e^+ e^-$ annihilation near $\sqrt{s}=10.6 \mathrm{GeV}$. The analysis is based on an $86.9 \mathrm{fb^{-1}}$ data sample collected %at and 60 MeV below the $\Upsilon(4S)$ resonance with with the Belle detector at KEKB. We determine the masses to be $M(D_{sJ}^+(2317)) = 2317.2 \pm 0.5(\mathrm{stat}) \pm 0.9(\mathrm{syst}) \mathrm{MeV}/c^2$ and $M(D_{sJ}^+(2457))=2456.5 \pm 1.3(\mathrm{stat}) \pm 1.3(\mathrm{syst}) \mathrm{MeV}/c^2$. We observe the radiative decay mode $D_{sJ}^+(2457) \to D_s^+ \gamma$ and the dipion decay mode $D_{sJ}^+(2457) \to D_s^+ \pi^+ \pi^-$, and determine their branching fractions. No corresponding decays are observed for the $D_{sJ}(2317)$ state. These results are consistent with the spin-parity assignments of $0^+$ for the $D_{sJ}(2317)$ and $1^+$ for the $D_{sJ}(2457)$., Comment: 5 pages, 6 figures; Added content, updated and paper submitted to PRL

Published
2003

20. Lattice diagnostics using single kick closed orbit at KEKB

Author

D. Pestrikov, Kazuhito Ohmi, N. Akasaka, Katsunobu Oide, Y. Funakoshi, K. Akai, N. Huan, Makoto Tobiyama, Satoshi Ohsawa, Yukiyoshi Ohnishi, Toshihiro Mimashi, Yujiro Ogawa, Eiji Kikutani, Yusuke Suetsugu, Norihito Ohuchi, Masaaki Suetake, Kenji Hosoyama, S. Yoshimoto, Tsuyoshi Suwada, Mitsuo Kikuchi, Takuya Kamitani, Tatsuro Nakamura, T. Ieiri, Noboru Yamamoto, Mika Masuzawa, T. Tawada, Shigeki Kato, Naoko Iida, Kazuro Furukawa, J. Ftanagan, K. Satoh, Masafumi Tawada, M. Yoshida, Shinichiro Michizono, Atsushi Enomoto, Shigenori Hiramatsu, Haruyo Koiso, Masaki Tejima, and Hitoshi Fukuma

Subjects
Physics, KEKB, Lattice (order), Magnet, Physics::Accelerator Physics, Beat (acoustics), Atomic physics, Closed orbit, Computational physics
Abstract

We have measured beta functions using single kick closed orbit at KEKB. The measured beta functions were compared with the model lattice and gradient errors were extracted from the result in a beta beat. The gradient errors were also obtained by changing strength of steering magnets and measuring beam positions as the second method. The methods of the error estimation and preliminary results are reported.

Published
2003
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21. Collision with finite crossing angle at KEKB

Author

Kazuhito Ohmi, Masafumi Tawada, and Yoshihiro Funakoshi

Subjects
Nuclear physics, Physics, KEKB, Luminosity (scattering theory), Electron optics, Physics::Accelerator Physics, High Energy Physics::Experiment, Beam optics, Atomic physics, Collision, Space charge, B-factory
Abstract

KEK B factory (KEKB) achieved the luminosity of 1034 cm−2s−1 with a finite crossing angle scheme. The crossing angle made easy the design of the interaction region for a narrow bunch spacing, with the result that it gave a gain of high collision repetition. The crossing angle did not degrade the beam‐beam performance up to the beam‐beam parameter of ξ ≈ 0.05. We review the beam‐beam effect of KEKB as a successive case of collision with finite crossing angle.

Published
2003
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22. Dynamic aperture with multipoles of special magnets in the KEKB interaction region

Author

Haruyo Koiso, Masafumi Tawada, H. Nakayama, and K. Oide

Subjects
Physics, Field (physics), Electromagnet, Computational physics, law.invention, Dynamic aperture, KEKB, law, Electron optics, Magnet, Orbit (dynamics), Physics::Accelerator Physics, Atomic physics, Multipole expansion
Abstract

At KEKB, six quadrupoles of special shapes are placed in the interaction region. Those quadrupoles are accompanied by higher-order multipole components which are prominent sources to degrade the dynamic aperture, and which even affect the linear optics because the design orbit passes through one of the special quadrupoles off-axis. In order to represent realistic field distributions of those quadrupoles obtained by hardware design, we take the higher-order multipoles up to 21st into account in our simulation. Using this model, we have redesigned the linear lattice and have estimated tolerances on the magnitudes of multipole components.

Published
2002
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23. REPORT FROM GROUP C

Author

Yi Sun, Yuko Takasu, Dinh Phu Tran, Md. Mashiur Rahman, Tiejun Meng, Anqi Zhou, Ganlin Ni, Harue Sugiyama, Masafumi Tawada, Ziqang Zeng, and Su Su Win

Subjects
Stereochemistry, Chemistry
Published
2002
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24. First Beam Collision in the KEKB

Author

Mika Masuzawa, Mitsuo Kikuchi, N. Huan, Masaaki Suetake, Toshihiro Mimashi, T. Ieiri, Satoshi Ohsawa, Yusuke Suetsugu, Katsunobu Oide, S. Yoshimoto, Norihito Ohuchi, K. Satoh, N. Akasaka, Tatsuro Nakamura, Shigeki Kato, K. Furtkawa, M. Yoshida, Haruyo Koiso, Masaki Tejima, Masafumi Tawada, Naoko Iida, J.W. Flanagan, Eiji Kikutani, K. Ohmi, Shinichiro Michizono, Takuya Kamitani, Noboru Yamamoto, Kazunori Akai, Yoshihiro Funakoshi, Kenji Hosoyama, Makoto Tobiyama, H. Fukuma, Atsushi Enomoto, Yukiyoshi Ohnishi, Yujiro Ogawa, Shigenori Hiramatsu, Tsuyoshi Suwada, and D. Pestrikov

Subjects
Nuclear physics, Physics, KEKB, Deflection (engineering), Physics::Accelerator Physics, High Energy Physics::Experiment, Laser beam quality, Atomic physics, Particle beam, Collision, Accelerators and Storage Rings, Double ring
Abstract

The first beam collision study was done in the KEKB double ring collider. Beam collision conditions were found by searching beam-beam deflection curves in a trial-and-error method. From these curves, beam sizes at IP and a luminosity was estimated.

Published
1999

25. Commissioning Of The Kekb B-factory

Author

Shigeki Kato, Shinichiro Michizono, Haruyo Koiso, Masaki Tejima, Takuya Kamitani, Naoko Iida, Kazuro Furukawa, Norihito Ohuchi, Noboru Yamamoto, Mitsuo Kikuchi, Kazunori Akai, Mika Masuzawa, Makoto Tobiyama, Yoshihiro Funakoshi, Shigenori Hiramatsu, Atsushi Enomoto, Toshihiro Mimashi, Yusuke Suetsugu, Satoshi Ohsawa, N. Huang, Kenji Hosoyama, T. Ieiri, N. Akasaka, J.W. Flanagan, Masakazu Yoshioka, K. Satoh, H. Fukuma, Yukiyoshi Ohnishi, K. Ohmi, Masafumi Tawada, Katsunobu Oide, Eiji Kikutani, Tsuyoshi Suwada, Yujiro Ogawa, J. Haba, S. Yoshimoto, Shin-ichi Kurokawa, M. Yoshida, T. E. Browder, Masaaki Suetake, D. Pestrikov, and Tatsuro Nakamura

Subjects
Physics, Nuclear physics, KEKB, law, Project commissioning, Detector, Collider, Particle beam, Status report, XX, law.invention, B-factory
Abstract

The commissioning of the KEKB B-Factory storage rings started on Dec. 1, 1998. The two rings both achieved a stored current of over 0.5 A after operating for four months. The two beams were successfully collided several times. The commissioning stopped on Apr. 19, taking a 5-week break to install the Belle detector.

Published
1999

26. The KEKB injector linac

Author

Yukinori Kobayashi, M. Ikeda, Satoshi Ohsawa, K. Yokoyama, Dai Arakawa, Shuji Matsumoto, Takashi Sugimura, Tsuyoshi Suwada, Y. Funakoshi, Akira Ueda, Mitsuhiro Yoshida, H. Matsushita, A. Shirakawa, Katsunobu Oide, T. Oogoe, Yukiyoshi Ohnishi, Masafumi Tawada, Takuya Kamitani, Hiroaki Katagiri, Masaaki Suetake, Yujiro Ogawa, Sergey Kazakov, Takashi Obina, T. Kasuga, Toshiyuki Mitsuhashi, Kazuhisa Kakihara, Mitsuo Akemoto, S. Michizono, A. Enomoto, Hiroyuki Honma, Toshiyasu Higo, Mitsuo Kikuchi, Tsukasa Miyajima, M. Tadano, Masanori Satoh, Toshihiro Mimashi, Toshihiro Matsumoto, Yoshiharu Yano, Katsumi Nakao, Noboru Kudou, Tateru Takenaka, Naoko Iida, Miho Kurashina, Kazuro Furukawa, Hiromitsu Nakajima, Tohru Honda, Tetsuo Shidara, Shigeki Fukuda, Shinya Nagahashi, Haruyo Koiso, and Takako Miura

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, Injector, Linear particle accelerator, law.invention, Nuclear physics, Acceleration, KEKB, Upgrade, Positron, law, Physics::Accelerator Physics, High Energy Physics::Experiment
Abstract

An 8-GeV electron/3.5-GeV positron injector for KEKB was completed in 1998 by upgrading the existing 2.5-GeV electron/positron linac. The main goals were to upgrade its accelerating energy from 2.5 to 8 GeV and to increase the positron intensity by about 20 times. This article describes not only the composition and features of the upgraded linac, but also how these goals were achieved, by focusing on an optics design and commissioning issues concerning especially high-intensity single-bunch acceleration to produce positron beams. r 2002 Elsevier Science B.V. All rights reserved.

Published
2013
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27. Accelerator design at SuperKEKB

Author

Hitoshi Fukuma, Toshikazu Adachi, Michiru Nishiwaki, Katsunobu Oide, Kazuro Furukawa, Ken-ichi Kanazawa, Makoto Tobiyama, Demin Zhou, Masafumi Tawada, M. Iwasaki, Mika Masuzawa, Haruyo Koiso, Akio Morita, Tatsuya Kageyama, Kyo Shibata, N. Tokuda, Toshihiro Mimashi, Takako Miura, Hiromi Iinuma, Mitsuo Kikuchi, Mitsuhiro Yoshida, Yusuke Suetsugu, Hiroshi Sugimoto, Yoshihiro Funakoshi, J.W. Flanagan, Takaaki Furuya, S. Kamada, Masanori Satoh, Hoitomi Ikeda, S. Yoshimoto, Kiyokazu Ebihara, Kiyosumi Tsuchiya, Masaaki Ono, Ryuhei Sugahara, Naoko Iida, Kota Nakanishi, Masaaki Suetake, Yasushi Arimoto, Kazuhito Ohmi, Yoshiharu Yano, Takuya Ishibashi, Zhanguo Zong, Hiroshi Yamaoka, Tsuyoshi Suwada, Takashi Mori, Tetsuo Abe, Takuya Kamitani, Kazumi Egawa, K. Akai, Norihito Ohuchi, Tatsuro Nakamura, Hiroyuki Nakayama, Toshiyuki Oki, Yukiyoshi Ohnishi, and Yujiro Ogawa

Subjects
Physics, General Physics and Astronomy, Mathematical physics
Abstract

Accelerator design at SuperKEKB Yukiyoshi Ohnishi∗, Tetsuo Abe, Toshikazu Adachi, Kazunori Akai, Yasushi Arimoto, Kiyokazu Ebihara, Kazumi Egawa, John Flanagan, Hitoshi Fukuma, Yoshihiro Funakoshi, Kazuro Furukawa, Takaaki Furuya, Naoko Iida, Hiromi Iinuma, Hoitomi Ikeda, Takuya Ishibashi, Masako Iwasaki, Tatsuya Kageyama, Susumu Kamada, Takuya Kamitani, Ken-ichi Kanazawa, Mitsuo Kikuchi, Haruyo Koiso, Mika Masuzawa, Toshihiro Mimashi, Takako Miura, Takashi Mori, Akio Morita, Tatsuro Nakamura, Kota Nakanishi, Hiroyuki Nakayama, Michiru Nishiwaki, Yujiro Ogawa, Kazuhito Ohmi, Norihito Ohuchi, Katsunobu Oide, Toshiyuki Oki, Masaaki Ono, Masanori Satoh, Kyo Shibata, Masaaki Suetake, Yusuke Suetsugu, Ryuhei Sugahara, Hiroshi Sugimoto, Tsuyoshi Suwada, Masafumi Tawada, Makoto Tobiyama, Noboru Tokuda, Kiyosumi Tsuchiya, Hiroshi Yamaoka, Yoshiharu Yano, Mitsuhiro Yoshida, Shin-ichi Yoshimoto, Demin Zhou, and Zhanguo Zong

Published
2013
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29. Commissioning of KEKB

Author

Naoko Iida, Yunhai Cai, Satoshi Ohsawa, Shin-ichi Kurokawa, Yasuchika Yamamoto, K. Yokoyama, Kazumi Egawa, Demin Zhou, J. Haba, Shigenori Hiramatsu, Sadaharu Uehara, Mitsuo Kikuchi, Masakazu Yoshioka, E. Perevedentsev, Haruyo Koiso, Masaki Tejima, Mika Masuzawa, Masaaki Ono, Katsunobu Oide, Toshiyuki Oki, Kiyokazu Ebihara, Tatsuro Nakamura, Miho Shimada, Takako Miura, Yoshiharu Yano, H. Fukuma, T. Ieiri, Yoshihiro Funakoshi, Masafumi Tawada, Masaaki Suetake, Zhanguo Zong, Hitomi Ikeda, Osamu Tajima, Kyo Shibata, Takaaki Furuya, Kazuro Furukawa, Akio Morita, Michiru Nishiwaki, Yukiyoshi Ohnishi, S. Kamada, Yujiro Ogawa, Takashi Sugimura, Kazuhito Ohmi, Atsushi Enomoto, Mitsuhiro Yoshida, Norihito Ohuchi, Shoji Uno, S. Yoshimoto, Tatsuya Kageyama, Yoshiyuki Morita, N. Tokuda, J.W. Flanagan, Masanori Satoh, Tetsuo Abe, Tsuyoshi Suwada, Kotaro Satoh, Kenji Hosoyama, Masato Yoshida, Takuya Kamitani, Toshihiro Matsumoto, Kazunori Akai, M. Iwasaki, Toshihiro Mimashi, Yusuke Suetsugu, Kota Nakanishi, Eiji Kikutani, Yuji Seimiya, Makoto Tobiyama, and Shigeki Kato

Subjects
Nuclear physics, Physics, Luminosity (scattering theory), KEKB, Electromagnetic coil, Detector, General Physics and Astronomy, Solenoid
Abstract

KEKB has been operated since December, 1998, to deliver B ¯ B pairs for a physics detector. In this paper,we describe the commissioning procedure of KEKB.

Published
2013
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30. Achievements of KEKB

Author

K. Yoshino, Eiji Kako, Hiroshi Sakai, Hitoshi Fukuma, Kota Nakanishi, Takashi Sugimura, Noboru Yamamoto, Y. Sakamoto, Kazumi Egawa, S. Isagawa, Shigeki Kato, A. Shirakawa, Eiji Kikutani, H. Nakanishi, S. Takasaki, M. Arinaga, Kyo Shibata, Takuya Kamitani, Shigemi Inagaki, Akio Morita, Tetsuo Shidara, Kazunori Akai, Hiroyuki Honma, Yasunobu Ohsawa, T. Ieiri, Naoko Iida, Toshiyuki Ozaki, Toshiyuki Mitsuhashi, Kazuhito Ohmi, S. Mitsunobu, T. Kawamoto, Eiji Ezura, M. Sato, S. Kamada, Shoji Uno, Mitsuhiro Yoshida, Shinichiro Michizono, N. Tokuda, K. Mikawa, I. Komada, S. Takano, Masaaki Suetake, Toshiyasu Higo, Atsushi Enomoto, Demin Zhou, Katumi Nakao, Osamu Tajima, Ken-ichi Kanazawa, Tateru Takenaka, Haruyo Koiso, Masaki Tejima, Yasunao Takeuchi, Miho Shimada, Yoshiharu Yano, Kiyosumi Tsuchiya, Yuuji Kojima, Toshiyuki Oki, Kiyokazu Ebihara, Teruya Honma, Satoshi Ohsawa, Hiromi Hisamatsu, M. Ikeda, Kazuro Furukawa, Toshihiro Mimashi, Takako Miura, T. Kubo, Masakazu Yoshioka, Katsunobu Oide, K. Yokoyama, H. Nakayama, E. Kadokura, Yusuke Suetsugu, Ryuhei Sugahara, Tatsuro Nakamura, S. Yoshimoto, Hitoshi Ishii, K. Mori, Shuji Matsumoto, Mika Masuzawa, T. Sueno, Shigeki Fukuda, Mitsuo Akemoto, Sergey Kazakov, Yingzhi Wu, J. Haba, A. Akiyama, Masafumi Tawada, Hirotaka Nakai, Tsuyoshi Suwada, E. Perevedentsev, Mitsuo Kikuchi, Yuji Seimiya, Hitomi Ikeda, Norimasa Akasaka, K. Marutsuka, Yunhai Cai, Sadaharu Uehara, Kazufumi Hara, Makoto Tobiyama, Kenji Hosoyama, Shigenori Hiramatsu, Zhanguo Zong, Tatsuya Kageyama, Hiromitsu Nakajima, Yoshihiro Funakoshi, Michiru Nishiwaki, Tetsuo Abe, Frank Zimmermann, J.W. Flanagan, Masanori Satoh, Hiroaki Katagiri, Yukiyoshi Ohnishi, Kiyoshi Kitagawa, Takaaki Furuya, Yujiro Ogawa, Masato Yoshida, Atsushi Kabe, Toshihiro Matsumoto, Shin-ichi Kurokawa, Yasuchika Yamamoto, Y. Takeuchi, Yoshiyuki Morita, Kotaro Satoh, K. Kudo, Mitsuru Shirai, Norihito Ohuchi, Kazuhisa Kakihara, Masaaki Ono, and Samo Stanic

Subjects
Physics, Upgrade, KEKB, business.industry, Electrical engineering, General Physics and Astronomy, business
Abstract

The machine commissioning of KEKB started in December 1998 and its operation was terminated at the end of June 2010 to upgrade KEKB to SuperKEKB. In this paper, we summarize the history of KEKB and show the achievements made there.

Published
2013
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31. Development of the Superconducting Quadrupole Magnet for the SuperKEKB Final Focusing System

Author

Masafumi Tawada, Kiyosumi Tsuchiya, M. Iwasaki, Norio Higashi, Zhanguo Zong, Norihito Ohuchi, and Toshiyuki Oki

Subjects
Superconductivity, Physics, Superconducting magnet, Electron, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Magnetic field, Nuclear physics, Magnet, Quadrupole, Physics::Accelerator Physics, Electrical and Electronic Engineering, Quadrupole magnet, Excitation
Abstract

We have developed the superconducting final-focus quadrupoles for SuperKEKB, the next generation B-factory experiment in Japan. The system consists of four quadrupole doublets for incoming and outgoing electron and positron beams, respectively. A R&D superconducting quadrupole magnet was fabricated. In this paper, we describe the results on the excitation test and the magnetic field measurements of this R&D magnet.

Published
2012
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32. REPORT FROM GROUP C.

Author

TIBJUN MENG, GANLIN NI, RAHMAN, MD. MASHIUR, HARUE SUGIYAMA, YI SUN, YUKO TAKASU, MASAFUMI TAWADA, DINH PHU TRAN, SU SU WIN, ZIQANG ZENG, and ANQI ZHOU

Subjects
SUPERCONDUCTING magnets, ACCELERATOR magnets, SOLENOID magnetic fields, MICROFABRICATION, MAGNETIC flux density
Published
2002

34. Beam-beam experience at KEKB

Author

Makoto Tobiyama, Noboru Yamamoto, E. Perevedentsev, N. Akasaka, Y. Wu, Norihito Ohuchi, Tsuyoshi Suwada, Mitsuo Kikuchi, Haruyo Koiso, Masaki Tejima, Shigeki Kato, Shin-ichi Kurokawa, Kazuro Furukawa, Naoko Iida, Takuya Kamitani, S. Yoshimoto, S. Uno, K. Akai, Shinichiro Michizono, Frank Zimmermann, J.W. Flanagan, Katsunobu Oide, D. Pestrikov, Mika Masuzawa, Atsushi Enomoto, Shigenori Hiramatsu, Tatsuro Nakamura, Hitoshi Fukuma, Yukiyoshi Ohnishi, K. Ohmi, T. Ieiri, Eiji Kikutani, Yujiro Ogawa, Masaaki Suetake, Karl Bane, M. Yoshida, H. Ikeda, N. Huang, Toshihiro Matsumoto, Y. Funakoshi, Masakazu Yoshioka, Kenji Hosoyama, J. Haba, Toshihiro Mimashi, Yusuke Suetsugu, Satoshi Ohsawa, K. Satoh, C. H. Yu, and Masafumi Tawada

Subjects
Physics, Nuclear physics, KEKB, Luminosity (scattering theory), business.industry, law, Electrical engineering, Particle accelerator, business, Linear particle accelerator, Beam (structure), law.invention
Abstract

KEKB has achieved the peak luminosity of 4.1 x 10{sup 33} cm{sup -2} sec{sup -1} and the present capability for delivering integrated luminosity is 224 pb{sup -1}/day. This paper describes (1) the recent performance and the problems of KEKB and (2) the comparison of beam-beam simulations with experiments at KEKB.

35. Difference in direct charge-parity violation between charged and neutral B meson decays

Author

R. Mizuk, L. E. Piilonen, G. Pakhlova, Y. Ogawa, S. Eidelman, L. S. Peak, S. Nishida, Yoshinobu Unno, Y. Sakai, D. Epifanov, I. S. Cho, M. Starič, W. S. Hou, S. Uno, Y. Hoshi, K. Arinstein, M. Iwabuchi, A. Ishikawa, Y. Yusa, Vladislav Balagura, J. Schümann, K. Hayasaka, A. Bay, Tariq Aziz, S. Uehara, Y. Choi, A. M. Bakich, H. Ha, S. L. Olsen, T. Hara, A.S. Kuzmin, S. Noguchi, C. H. Wang, S. Fratina, S. E. Lee, T. Nozaki, F. Takasaki, T. Ohshima, C. W. Park, P. Križan, S. Ogawa, H. Kaji, Y. Iwasaki, M. Iwasaki, Y. J. Kwon, P. Goldenzweig, W. T. Chen, M. Yamauchi, N. Gabyshev, V.N. Zhilich, S. Suzuki, O. Schneider, P. Chang, Masafumi Tawada, D. Liventsev, K. Ueno, Masahiro Fujikawa, N. Tamura, H. Park, A. Bozek, W. A. Mitaroff, D. H. Kah, M. Dash, Andrey Sokolov, T. Iijima, Iki Adachi, G. S. Varner, R. Chistov, C. C. Zhang, H. Shibuya, H. Kichimi, S. Cole, Y. B. Hsiung, H. Miyake, Young-Il Choi, K. Miyabayashi, A. Somov, P. Krokovny, K. Trabelsi, T. Lesiak, S. Villa, Yu-xi Liu, R. Itoh, C. P. Shen, Zhenyu Zhang, Kazuro Furukawa, R. Seidl, S. Shinomiya, Toshihiro Mimashi, M. Tanaka, Yu. V. Usov, Y. Yamashita, S. Okuno, M. Yoshida, A. Bondar, K. Sumisawa, E. Nakano, J. Dalseno, T. E. Browder, Takashi Nakamura, T. Aushev, S. K. Choi, A. Drutskoy, M. Z. Wang, K. Kinoshita, Tetsuo Shidara, K. Vervink, M. C. Chang, C. C. Wang, Eiji Kikutani, K. Ikado, Y. Teramoto, Bruce Yabsley, M. Danilov, J. Haba, C. C. Kuo, H. Nakazawa, Masashi Hazumi, Tatiana Medvedeva, Kai-Feng Chen, A. Yamaguchi, Y. Kozakai, D. Heffernan, Y. Chao, M. J. Lee, M. Bračko, G. N. Taylor, B. Golob, Rakesh Kumar, J. G. Shiu, Jasvinder A. Singh, S. W. Lin, H. Sahoo, E. Won, K. Senyo, Daniel Robert Marlow, Samo Stanič, T. Uglov, A. J. Schwartz, F. Mandl, Vladimir Zhulanov, M. E. Sevior, H. J. Kim, T. Kawasaki, Kevin Varvell, C. C. Chiang, Hirokazu Ishino, Phillip Urquijo, H. Kawai, J. Wicht, T. Mori, K. Inami, T. Sumiyoshi, Anton Poluektov, A. Kibayashi, M. Nakao, S. McOnie, H. Hayashii, S. K. Kim, Osamu Tajima, A. Zupanc, O. Nitoh, B. G. Cheon, I. Tikhomirov, A. Chen, M. Shapkin, Hiroaki Aihara, Robin Wedd, Y. J. Kim, Y. Ushiroda, C. Z. Yuan, H. Ozaki, M. D. Peters, R. Pestotnik, I. Bedny, J. Li, Y. Watanabe, B. Shwartz, V. M. Aulchenko, E. L. Barberio, H. J. Hyun, Y. Miyazaki, T. Hokuue, Samo Korpar, S. U. Kataoka, K. Akai, and U. Bitenc

Subjects
Physics, Antiparticle, Particle physics, Multidisciplinary, Meson, 010308 nuclear & particles physics, Electron–positron annihilation, media_common.quotation_subject, 01 natural sciences, Asymmetry, Standard Model, Nuclear physics, Antimatter, 0103 physical sciences, CP violation, B meson, 010306 general physics, media_common
Abstract

Equal amounts of matter and antimatter are predicted to have been produced in the Big Bang, but our observable Universe is clearly matter-dominated. One of the prerequisites for understanding this elimination of antimatter is the nonconservation of charge-parity (CP) symmetry. So far, two types of CP violation have been observed in the neutral K meson (K(0)) and B meson (B(0)) systems: CP violation involving the mixing between K(0) and its antiparticle (and likewise for B(0) and ), and direct CP violation in the decay of each meson. The observed effects for both types of CP violation are substantially larger for the B(0) meson system. However, they are still consistent with the standard model of particle physics, which has a unique source of CP violation that is known to be too small to account for the matter-dominated Universe. Here we report that the direct CP violation in charged B(+/-)-->K(+/-)pi(0) decay is different from that in the neutral B(0) counterpart. The direct CP-violating decay rate asymmetry, (that is, the difference between the number of observed B(-)-->K(-)pi(0) event versus B(+)-->K(+) pi(0) events, normalized to the sum of these events) is measured to be about +7%, with an uncertainty that is reduced by a factor of 1.7 from a previous measurement. However, the asymmetry for versus B(0)-->K(+)pi(-) is at the -10% level. Although it is susceptible to strong interaction effects that need further clarification, this large deviation in direct CP violation between charged and neutral B meson decays could be an indication of new sources of CP violation-which would help to explain the dominance of matter in the Universe.

36. Lattice analysis of the KEKB colliding rings

Author

M. Yoshida, Norihito Ohuchi, Kazuhito Ohmi, Takuya Kamitani, Kazunori Akai, D. Pestrikov, Makoto Tobiyama, H. Fukuma, N. Akasaka, Shigeki Kato, Satoshi Ohsawa, Yoshihiro Funakoshi, N. Huang, S. Yoshimoto, Mitsuo Kikuchi, K. Satoh, Katsunobu Oide, Naoko Iida, Kazuro Furukawa, Masaaki Suetake, Yukiyoshi Ohnishi, Masafumi Tawada, Mika Masuzawa, Shigenori Hiramatsu, Tatsuro Nakamura, Toshihiro Mimashi, Yujiro Ogawa, Kenji Hosoyama, Yusuke Suetsugu, T. Ieiri, Haruyo Koiso, Masaki Tejima, Eiji Kikutani, J. Managan, Shinichiro Michizono, Atsushi Enomoto, Noboru Yamamoto, and Tsuyoshi Suwada

Subjects
Nuclear physics, Physics, Nonlinear Sciences::Adaptation and Self-Organizing Systems, KEKB, Electromagnet, law, Lattice (order), Physics::Accelerator Physics, Computer Science::Software Engineering, High Energy Physics::Experiment, Atomic physics, Accelerators and Storage Rings, law.invention
Abstract

A low beta lattice with /spl beta/x*//spl beta/y*=100/1 cm has been realized in the KEKB colliding rings. The basic optical parameters have been measured and compared with the model.

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