Readout Electronics for the CALICE ECAL and Tile HCAL
The aims of the CALICE test beam program are presented. The proposed electronics readout system for the CALICE ECAL is described. It is a purpose-built VME-based, unbuffered system.
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arXiv subjects
P. D. Dauncey
Publications and source records attributed to P. D. Dauncey.
Measurements of branching fractions and CP-violating asymmetries in B0 -> pi+pi-, K+pi-, K+K- decays
We present updated measurements of branching fractions and CP-violating asymmetries for neutral B meson decays to two-body final states of charged pions and kaons. The results are obtained from a data sample of about 60 million Y(4S) to BB decays collected between 1999 and 2001 by the BaBar detector at the Pep-II asymmetric-energy B Factory at SLAC. The sample contains 124+16-15 pipi, 403+-24 Kpi, and 1+8-7 KK candidates, from which we measure the following quantities: B(B0 -> pi+pi-) = (5.4 +- 0.7 +- 0.4) x 10^(-6) B(B0 -> K+pi-) = (17.8 +- 1.1 +- 0.8) x 10^(-6) B(B0 -> K+K-) < 1.1 x 10^-6 (90% C.L.) Kpi asymmetry = -0.05 +- 0.06 +- 0.01, 90% C.L. [-0.14, +0.05] Spipi = -0.01 +- 0.37 +- 0.07, 90% C.L. [-0.66, +0.62] Cpipi = -0.02 +- 0.29 +- 0.07, 90% C.L. [-0.54, +0.48] where the errors are statistical and systematic, respectively. These results are preliminary.
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Design and Performance of the Level 1 Calorimeter Trigger for the BABAR Detector
Since May 1999 the BABAR detector has been taking data at the PEP-II asymmetric electron-positron collider at the Stanford Linear Accelerator Center, California. This experiment requires a very large data sample and the PEP-II accelerator uses intense beams to deliver the high collision rates needed. This poses a severe challenge to the BaBar trigger system, which must reject the large rate of background signals resulting from the high beam currents whilst accepting the collisions of interest with very high efficiency. One of the systems that performs this task is the Level 1 Calorimeter Trigger, which identifies energy deposits left by particles in the BABAR calorimeter. It is a digital, custom, fixed latency system which makes heavy use of high-speed FPGA devices to allow flexibility in the choice of data filtering algorithms. Results from several intermediate processing stages are read out, allowing the selection algorithm to be fully analysed and optimized offline. In addition, the trigger is monitored in real time by sampling these data and cross-checking each stage of the trigger calculation against a software model. The design, implementation, construction and performance of the Level 1 Calorimeter Trigger during the first year of BABAR operation are presented.
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