Study of B Decays to Charmonium States: B-->eta(c)K and B --> chi(c0)K.
Physical review letters 86:1 (2001) 30-34
Abstract:
In a sample of 9.66x10(6)B&Bmacr; pairs collected with the CLEO detector we make the first observation of B decays to an eta(c) and a kaon. We measure branching fractions B(B+-->eta(c)K+) = (0.69(+0.26)(-0.21)+/-0.08+/-0.20)x10(-3) and B(B degrees -->eta(c)K degrees ) = (1.09(+0.55)(-0.42)+/-0.12+/-0.31)x10(-3), where the first error is statistical, the second is systematic, and the third is from the eta(c) branching fraction uncertainty. From these we extract the eta(c) decay constant in the factorization approximation, f(eta(c)) = 335+/-75 MeV. We also search for B decays to a chi(c0) and a kaon. No evidence for a signal is found and we set 90% C.L. upper limits: B(B+-->chi(c0)K+)<4.8x10(-4) and B(B degrees -->chi(c0)K degrees )<5.0x10(-4).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
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 product branching fraction B(c→ΘcX)×B(Θc→ΛX)
Physical Review D American Physical Society (APS) 62:9 (2000) 092007