Showing papers by "J. Haba published in 1988"
01 Sep 1988-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the VENUS barrel electromagnetic calorimeter at TRISTAN is described, which is composed of 5160 lead-glass counters in a semi-tower arrangement.
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.
23 citations
Tohoku University1, University of Tsukuba2, Tokyo Metropolitan University3, Hiroshima University4, Wakayama Medical University5, Tokyo University of Agriculture and Technology6, Osaka University7, Kyoto University8, Tohoku Gakuin University9, Kobe University10, University of Miyazaki11, Meiji Gakuin University12, University of Fukui13
TL;DR: A new mass limit on the charged heavy leptons was obtained as a function of the mass of the associated neutrinos as well as the integrated luminosity of 5.3 pb/sup -1/.
Abstract: A search for sequential charged leptons decaying into massive neutrinos has been performed at E/sub c.m./ = 56 GeV at the KEK collising-beam accelerator TRISTAN. We have found no evidence for the production of the charged heavy leptons for an integrated luminosity of 5.3 pb/sup -1/. A search for stable charged leptons was also conducted yielding null results. A new mass limit on the charged heavy leptons was obtained as a function of the mass of the associated neutrinos.
13 citations
15 Mar 1988-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the performance of limited streamer tubes operated with nonflammable gas mixtures composed of argon (Ar), carbon-dioxide (CO 2 ), and isobutane (i-C 4 H 10 ) with ratios of 1:1.5:0.15, 1:2: 0.2, 3:3:0., 4:4:0, and 5:6.6 were studied.
Abstract: Performances of limited streamer tubes operated with nonflammable gas mixtures composed of argon (Ar), carbon-dioxide (CO 2 ) and isobutane (i-C 4 H 10 ) with ratios of 1:1.5:0.15, 1:2:0.2, 1:3:0.3, 1:4:0.4 and 1:6:0.6 were studied. It was found that these mixtures were very suitable for the VENUS detector. The charge spectra exhibited very sharp distributions and indicated the possibility for the limited streamer tubes to be applied to calorimetry use. A mixture of 1:2:0.2 was chosen for the VENUS streamer tubes because of its moderate gain and long efficiency plateau.
7 citations
TL;DR: The polarization parameters for the π + +p→K + +∑ + reaction have been measured at 13 laboratory momenta between 1490 and 2069 MeV/c in the angular range of −01⩽ cos θ K ∗ ⩽07 with higher statistics than previous experiments.
6 citations
Tohoku University1, University of Tsukuba2, Tokyo Metropolitan University3, Hiroshima University4, Wakayama Medical University5, Tokyo University of Agriculture and Technology6, Osaka University7, Kyoto University8, Tohoku Gakuin University9, Kobe University10, University of Miyazaki11, Meiji Gakuin University12, University of Fukui13
TL;DR: In this paper, a lower limit for the mass of excited electrons, e ∗' s, has been obtained by making use of the processes e + e − →e + e− γγ and e − γ ( e ) (quasi-real Compton scattering).
5 citations
Tohoku University1, University of Tsukuba2, Tokyo Metropolitan University3, Hiroshima University4, Wakayama Medical University5, Tokyo University of Agriculture and Technology6, Osaka University7, Kyoto University8, Tohoku Gakuin University9, Kobe University10, University of Miyazaki11, Meiji Gakuin University12, University of Fukui13
TL;DR: In this paper, the authors studied lepton production in e + e − annihilations into multihadrons in the energy range between √ s = 50 and 55 GeV using the VENUS detector at TRISTAN, KEK.
3 citations
TL;DR: In this paper, the mass distribution in the dp → (pp)n reaction has been measured at the deuteron momentum from 1700 to 2280 MeV/c. The results show no prominent peak which suggests the existence of dibaryon resonances in the mass range of 2000 to 2200 MeV /c2.
1 citations