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Measurement of the mass splittings between the bb̄χb,J(1P) states

Physical Review D Particles Fields Gravitation and Cosmology 59:3 (1999) 1-5

Authors:

KW Edwards, A Bellerive, R Janicek, DB MacFarlane, PM Patel, AJ Sadoff, R Ammar, P Baringer, A Bean, D Besson, D Coppage, C Darling, R Davis, S Kotov, I Kravchenko, N Kwak, L Zhou, S Anderson, Y Kubota, SJ Lee, JJ O'Neill, R Poling, T Riehle, A Smith, MS Alam, SB Athar, Z Ling, AH Mahmood, S Timm, F Wappler, A Anastassov, JE Duboscq, D Fujino, KK Gan, T Hart, K Honscheid, H Kagan, R Kass, J Lee, H Schwarthoff, MB Spencer, M Sung, A Undrus, A Wolf, MM Zoeller, SJ Richichi, H Severini, P Skubic, M Bishai, J Fast, JW Hinson, N Menon, DH Miller, EI Shibata, IPJ Shipsey, M Yurko, S Glenn, Y Kwon, AL Lyon, S Roberts, EH Thorndike, CP Jessop, K Lingel, H Marsiske, ML Perl, V Savinov, D Ugolini, X Zhou, TE Coan, V Fadeyev, I Korolkov, Y Maravin, I Narsky, V Shelkov, J Staeck, R Stroynowski, I Volobouev, J Ye, M Artuso, F Azfar, A Efimov, M Goldberg, D He, S Kopp, GC Moneti, R Mountain, S Schuh, T Skwarnicki, S Stone, G Viehhauser, JC Wang, X Xing, J Bartelt, SE Csorna, V Jain, KW McLean, S Marka, R Godang, K Kinoshita, IC Lai

Abstract:

We present new measurements of photon energies and branching fractions for the radiative transitions Y(2S)→γχb(J=0,1,2)(1P). The masses of the χb states are determined from the measured radiative photon energies. The ratio of mass splittings between the χb substates, r≡(MJ=2-MJ=1)/(MJ=1-MJ=0), with M the χb mass, provides information on the nature of the bb̄ confining potential. We find r(1P)=0.542 ±0.022±0.024. This value is somewhat lower than the previous world average, but more consistent with the theoretical expectation that r(1P)b(1P) states than for the χb(2P) states. ©1999 The American Physical Society.

An aging study by semi-conductive microstrip gas chambers11Submitted for 1998 Symposium on Radiation Measurements and Applications, 12–14 May 1998, Ann Arbor, Michigan.

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment Elsevier 422:1-3 (1999) 282-285

Authors:

EKE Gerndt, BA Knapp, J Miyamoto, IPJ Shipsey, Q Zhang

Measurement of the Associated $γ+ μ^\pm$ Production Cross Section in $p \bar p$ Collisions at $\sqrt{s} = 1.8$ TeV

ArXiv hep-ex/9902001 (1999)

Aging study of a gas electron multiplier detector with microstrip gas chamber readout

IEEE Nuclear Science Symposium and Medical Imaging Conference 1 (1999) 598-602

Authors:

J Miyamoto, IPJ Shipsey

Abstract:

The aging behavior of wire chambers have been of great interest for many years. Recently a new generation of proportional chambers have been developed including the microstrip gas chamber (MSGC) microgap chamber (MGC) and gaseous electron multiplier (GEM). Aging studies of these detectors are of particular interest to the LHC (Large Hadron Collider) community because the baseline design of the CMS experiment includes MSGCs as part of the tracking system. We have performed an aging study of a GEM detector readout with a MSGC. The GEM is constructed from Kapton and copper, the MSGC is constructed from semiconductive glass and gold. When the detector is operated in argon and dimethyl ether (DME) gas mixture and irradiated with a 6 KeV photon beam, about 220 mC/cm of charge can be accumulated without degradation of the detector performance. This corresponds to about 20 years of operation at the LHC.

First Observation of the Decay τ- → K*-η ντ

Physical Review Letters 82:2 (1999) 281-285

Authors:

M Bishai, S Chen, J Fast, JW Hinson, N Menon, DH Miller, EI Shibata, IPJ Shipsey, S Glenn, Y Kwon, AL Lyon, S Roberts, EH Thorndike, CP Jessop, K Lingel, H Marsiske, ML Perl, V Savinov, D Ugolini, X Zhou, TE Coan, V Fadeyev, I Korolkov, Y Maravin, I Narsky, R Stroynowski, J Ye, T Wlodek, M Artuso, E Dambasuren, S Kopp, GC Moneti, R Mountain, S Schuh, T Skwarnicki, S Stone, A Titov, G Viehhauser, JC Wang, J Bartelt, SE Csorna, KW Mc Lean, S Marka, Z Xu, R Godang, K Kinoshita, IC Lai, P Pomianowski, S Schrenk, G Bonvicini, D Cinabro, R Greene, LP Perera, GJ Zhou, S Chan, G Eigen, E Lipeles, JS Miller, M Schmidtler, A Shapiro, WM Sun, J Urheim, AJ Weinstein, F Würthwein, DE Jaffe, G Masek, HP Paar, EM Potter, S Prell, V Sharma, DM Asner, J Gronberg, TS Hill, DJ Lange, RJ Morrison, HN Nelson, TK Nelson, D Roberts, BH Behrens, WT Ford, A Gritsan, H Krieg, J Roy, JG Smith, JP Alexander, R Baker, C Bebek, BE Berger, K Berkelman, V Boisvert, DG Cassel, DS Crowcroft, M Dickson, S Von Dombrowski, PS Drell, KM Ecklund, R Ehrlich, AD Foland, P Gaidarev, RS Galik

Abstract:

The decay τ-→ K*- η ν τ has been observed with the CLEO II detector. The K*- is reconstructed in two decay channels, K*-→ KSπ-→π+π- and K*-→ K-π0. The η is reconstructed from the decay η → γγ. The measured branching fraction isB(τ-→ K*-π η ντ)=(2.9 ± 0.8 ±0.4) × 10-44. We also measure the inclusive branching fractions without requiring the K* resonance, B(τ-→ KSπ- η ντ)=(1.10 ± 0.35 ±0.11) × 10-4 and B(τ-→ K-π0 η ντ)=(1.77 ± 0.56 ±0.71) × 10-4. The results indicate that the K*- resonance dominates the KSπ- mass spectrum. © 2000 The American Physical Society.