A study of a combination of MICROMEGAS+ GEM chamber in Ar-CO2 gas
IEEE Nuclear Science Symposium and Medical Imaging Conference 1 (2001) 265-268
Abstract:
A MICROMEGAS is a micropatterned gaseous detector that has great potential in many applications including high energy physics and astronomy. The detector consists of a micromesh supported by thin pillars (50 μm) and the space between the micromesh and the anode plane defines an amplification gap. The detector has a high rate capability and good spatial resolution. The performance of the MICROMEGAS can be improved by a preamplification device like a GEM to factor the gas multiplication into two stages. With the added preamplication, it is possible to minimize spark rates in detecting heavily ionizing particles without sacrificing gas gain significantly. The additional gas gain provided by the GEM also allows the detector to operate in a clean gas mixture like Ar-CO2 The use of a clean gas mixture allows the device to be radiation hard.Evidence for the decay D0→K+π-π+π-
Physical Review D American Physical Society (APS) 64:11 (2001) 111101
Evidence for the decay D0 → Κ+π-π+π-
Physical Review D 64:11 (2001)
Abstract:
We present a search for the "wrong-sign" decay D0 → Κ+π-π+π- using 9 fb-1 of e+e- collisions on and just below the Y(4S) resonance. This decay can occur either through a doubly Cabibbo-suppressed process or through mixing to a D̄0 followed by a Cabibbo-favored process. Our result for the time-integrated wrong-sign rate relative to the decay D0 → Κ-π+π-π+ is (0.0041-0.0011+0.0012(stat)±0.0004(syst))×(1.07 ±0.10)(phase space), which has a statistical significance of 3.9 standard deviations. ©2001 The American Physical Society.Branching fraction and photon energy spectrum for b --> s gamma.
Physical review letters 87:25 (2001) 251807