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Featured researches published by J. Haba.


Physics Letters B | 1987

Measurement of R and search for new heavy quarks in e+e- annihilation at 50 and 52 GeV centre-of-mass energies

Hajime Yoshida; Y. Chiba; I. Endo; I. Hayashibara; T. Ohsugi; A. Taketani; R. Tanaka; K. Amako; Y. Arai; Herbert Friedrich Boerner; M. Fukawa; Y. Fukushima; N. Ishihara; J. Kanzaki; T. Kondo; Keisuke Maehata; T. Matsui; S. Odaka; K. Ogawa; T. Ohama; H. Sakamoto; M. Sakuda; J. Shirai; T. Sumiyoshi; F. Suekane; Y. Teramoto; F. Takasaki; T. Tsuboyama; S. Uehara; Yoshinobu Unno

Abstract The total cross section for the process of the e+e- annihilation into hadrons has been measured at the centre-of-mass energies of 50 GeV and 52 GeV and a search has been made for new heavy quarks. The ratios R = σ(e+e- → hadrons)/σpoint(e+e- → μ+μ-) obtained are 4.4±0.5 at 50 GeV and 4.7±0.3 at 52 GeV, respectively. An additional systematic uncertainty is 10%. From the event shape analysis we found no evidence for a new quark with charge 2 3 e .


Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 1988

Performance of the VENUS lead-glass calorimeter at TRISTAN

T. Sumiyoshi; K. Hayashi; K. Ogawa; F. Takasaki; J. Haba; T. Kamitani; Nobuyuki Kanematsu; H. Osabe; S. Sugimoto; T. Yamashita; M. Sakano; Hajime Yoshida; K. Shino

Abstract The initial performance of the VENUS barrel electromagnetic calorimeter at TRISTAN is described. The calorimeter is composed of 5160 lead-glass counters in a semi-tower arrangement. An energy resolution of 3.8% was obtained for 26 GeV Bhabha events. The neutral pions in the hadronic events were reconstructed with a mass resolution of σ = 16 MeV. The gain of the lead-glass counters was stable within 2% during a four months operation at TRISTAN.


Physics Letters B | 1997

Measurement of the proton-antiproton pair production from two-photon collisions at TRISTAN

H. Hamasaki; K. Abe; K. Amako; Y. Arai; Y. Asano; M. Chiba; Y. Chiba; Motomasa Daigo; M. Fukawa; Y. Fukushima; J. Haba; H. Hanai; Y. Hemmi; M. Higuchi; T. Hirose; Y. Homma; N. Ishihara; Y. Iwata; J. Kanzaki; R. Kikuchi; T. Kondo; T. T. Korhonen; H. Kurashige; E. K. Matsuda; T. Matsui; K. Miyake; S. Mori; Y. Nagashima; Y. Nakagawa; Takashi Nakamura

Abstract The cross section of the γγ → p p reaction was measured at two-photon center-of-mass energy (Wγγ) between 2.2 and 3.3 GeV, using the two-photon process at an e+e− collider, TRISTAN. The Wγγ dependence of the cross section integrated over a c.m. angular region of | cos θ ∗ | is in good agreement with the previous measurements and the theoreticalv prediction based on diquark model in the high Wγγ region.


Physics Letters B | 1990

Determination of the QCD scale parameter ΛMS with QCD cascade on the basis of the next-to-leading logarithmic approximation

K. Abe; K. Amako; Y. Arai; Y. Asano; M. Chiba; Y. Chiba; M. Daigo; T. Emura; M. Fukawa; T. Fukui; Y. Fukushima; J. Haba; D. Haidt; I. Hayashibara; Y. Hemmi; M. Higuchi; T. Hirose; Y. Hojo; Y. Homma; Y. Hoshi; Y. Ikegami; N. Ishihara; T. Kamitani; Nobuyuki Kanematsu; J. Kanzaki; R. Kikuchi; T. Kondo; T. Koseki; H. Kurashige; T. Matsui

Abstract The relative production ratio of 3-jet events to the total number of hadronic events was studied in e+e− annihilations at centre-of-mass energies between 54 and 61.4 GeV. The QCD scale parameter has been determined to be Λ MS =254 −47 +55 ±56 MeV on the basis of a QCD cascade with the next-to-leading logarithmic approximation.


Physics Letters B | 1990

Measurement of R and search for new quark flavors decaying into multi-jet final states in e+e− collisions between 54.0 and 61.4 GeV CM energies

K. Abe; K. Amako; Y. Arai; Y. Asano; Masami Chiba; Y. Chiba; M. Daigo; T. Emura; I. Endo; M. Fukawa; T. Fukui; Y. Fukushima; J. Haba; D. Haidt; I. Hayashibara; Y. Hemmi; M. Higuchi; T. Hirose; Y. Hojyo; Y. Homma; Y. Hoshi; Y. Ikegami; N. Ishihara; T. Kamitani; Nobuyuki Kanematsu; J. Kanzaki; R. Kikuchi; T. Kondo; T. Koseki; H. Kurashige

Abstract We accumulated e+e− annihilations into multi-hadrons at CM energies between 54.0 and 61.4 GeV with the VENUS detector at TRISTAN. Measured R-ratios are consistent with the standard model using the Z-boson mass; 91.1 GeV/c2. Using two new observables, we searched for a planar four-jet and other multi-jet events resulting from the decay of a charge — 1 3 e b quark. Having observed no positive signals, we excluded b masses between 19.4 and 28.2 GeV/c2 with a 95% confidence level, regardless of branching into charged current and loop-induced flavor-changing neutral current decay, including a possible Higgs decay process. The charge + 2 3 e top quark was excluded below f30.2 GeV/c2.


European Physical Journal C | 1989

Measurement of the differential cross sections ofe+e−→γγ ande+e−→γγγ at\(\sqrt s = 55,56,56.5\) and 57 GeV and search for unstable photino pair production

K. Abe; K. Amako; Y. Arai; M. Fukawa; Y. Fukushima; N. Ishihara; D. Haidt; J. Kanzaki; T. Kondo; T. Matsui; S. Odaka; K. Ogawa; T. Ohama; H. Sakamoto; J. Shirai; T. Sumiyoshi; F. Takasaki; T. Tsuboyama; S. Uehara; Yoshinobu Unno; Y. Watase; Y. Yamada; Y. Asano; T. Koseki; S. Mori; M. Sakano; Y. Takada; Y. Yonezawa; M. Chiba; T. Fukui

AbstractDifferential cross sections fore+e−→γγ have been measured at center-of-mass energies of 55, 56, 56.5 and 57 GeV. The results are in good agreement with those predicted by QED. Possible deviations from QED are studied in terms of contact interactions, and the limits on compositeness scales are obtained. Using events with a gramma pair in the final state, a search is made for the pair production of unstable photons,n


Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 1995

KEKB and the BELLE experiment

J. Haba


Physics Letters B | 1993

A study of the charm and bottom quark production in e+e− annihilation at s = 58 GeV using prompt electrons

K. Abe; K. Amako; Y. Arai; T. Arima; Y. Asano; M. Chiba; Y. Chiba; M. Daigo; M. Fukawa; Y. Fukushima; J. Haba; Y. Hemmi; M. Higuchi; F. Hinode; T. Hirose; Y. Homma; Y. Hoshi; N. Hosoda; N. Ishihara; E. Kanatani; N. Kanda; Nobuyuki Kanematsu; J. Kanzaki; R. Kikuchi; T. Kondo; T. T. Korhonen; A. E. Krüger; H. Kurashige; J. MacNaughton; T. Matsui

e^ + e^ - to tilde gamma tilde gamma


Physics Letters B | 1989

A study on single photon production at √s=54.0-61.4 GeV

K. Abe; K. Amako; Y. Arai; Y. Asano; M. Chiba; Y. Chiba; M. Daigo; T. Emura; I. Endo; M. Fukawa; T. Fukui; Y. Fukushima; J. Haba; D. Haidt; I. Hayashibara; Y. Hemmi; M. Higuchi; T. Hirose; Y. Hojyo; Y. Homma; Y. Hoshi; Y. Ikegami; N. Ishihara; T. Kamitani; Nobuyuki Kanematsu; J. Kanzaki; R. Kikuchi; T. Kondo; T. Koseki; H. Kurashige


nuclear science symposium and medical imaging conference | 1995

Fabrication of a double-sided silicon microstrip detector with an ONO capacitor dielectric film

Yutaka Saitoh; Tadao Akamine; Masahiro Inoue; Junko Yamanaka; K. Kadoi; R. Takano; Y. Kojima; S. Miyahara; Masaaki Kamiya; Hirokazu Ikeda; T. Matsuda; T. Tsuboyama; H. Ozaki; Masaaki Tanaka; H. Iwasaki; J. Haba; Y. Higashi; Y. Yamada; S. Okuno; S. Avrillon; T. Nemoto; I. Fukunishi; Y. Asano

n. No candidate events were found and a new limit on the photino mass is obtained.

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Y. Asano

University of Tsukuba

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Nobuyuki Kanematsu

National Institute of Radiological Sciences

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