An aging study of double GEMs in Ar-CO2
IEEE Nuclear Science Symposium and Medical Imaging Conference 1 (2000)
Abstract:
An aging study was performed using double OEMs and a printed circuit readout board (PCB) with an intense X-ray source in an ultra clean Argon-CO2 gas environment. The detector was irradiated continuously for about 1000 hours without interruption until a large amount of charge was accumulated. A single-wire chamber served as a monitoring device to check the beam and ambient conditions and gas chromatography was used to ensure no hydrocarbon materials were present in the gas mixture. The detector could withstand more than 25 mC/mm2 with only a slight sign of aging and the charge accumulated is presumably sufficient to conduct large-scale and long-term experiments in intense radiation fields.Measurement of B→Ds(*)+D*(*) branching fractions
Physical Review D American Physical Society (APS) 62:11 (2000) 112003
Measurement of sin 2β from B→J/φK s 0 with the CDF detector
Physical Review D 61:7 (2000)
Abstract:
This paper reports an updated measurement of the standard model CP violation parameter sin 2β using the CDF Detector at Fermilab. The entire run I data sample of 110 pb -1 of proton-antiproton collisions at √s = 1.8 TeV is used to identify a signal sample of ∼400 B→J/φK s0 events, where J/φ→μ + μ - →μ + μ - . The flavor of the neutral B meson is identified at the time of production by combining information from three tagging algorithms: a same-side tag, a jet-charge tag, and a soft-lepton tag. A maximum likelihood fitting method is used to determine sin 2β=0.79 -0.44+0.41 (stat+syst). This value of sin 2β is consistent with the standard model prediction, based upon existing measurements, of a large positive CP-violating asymmetry in this decay mode. ©2000 The American Physical Society.Resonant structure of τ→3 ππ 0 ν τ and τ→ωπν τ decays
Physical Review D 61:7 (2000)
Abstract:
The resonant structure of the four pion final state in the decay τ→3 ππ 0 ν τ has been analyzed using 4.27 million τ + τ - pairs collected by the CLEO II experiment at the Cornell Electron Storage Ring. A partial wave analysis of the resonant structure of the τ→3 ππ 0 ν τ decay has been performed; the spectral decomposition of the four pion system is dominated by the ωπ and a 1 π final states. The mass and width of the ρ′ resonance have been extracted from a fit to the τ→ωπν τ spectral function. We have searched for second class currents in the decay τ→ωπν τ using spin-parity analysis and established an upper limit on the non-vector current contribution. © 2000 The American Physical Society.Measurement of the Decay Amplitudes ofB 0 → J / ψ K * 0 andB s 0 → J / ψ φ Decays
Physical Review Letters American Physical Society (APS) 85:22 (2000) 4668-4673