Prompt K_short production in pp collisions at sqrt(s)=0.9 TeV

The production of K_short mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations.Comment: 6+18 pages, 6 figures, updated author lis

Development of an optical front-end readout system for the LHCb RICH detectors.

The development of a front-end readout system for the LHCb Ring Imaging Cherenkov (RICH) detectors is in progress. The baseline choice for the RICH photon detector front-end electronics is a binary readout ASIC for an encapsulated silicon pixel detector. This paper describes a system to transmit the binary data with address ID and error codes, from a radiation harsh environment while keeping synchronisation. The total data read out for the fixed Level-0 readout period of 900ns is 32x36x440 non-zero-suppressed bits per Level-0 trigger, with a sustained Level-0 trigger rate of 1MHz. Multimode fibres driven by VCSEL devices are used to transmit data to the off-detector Level-1 electronics located in a non-radiation environment. The data are stored in 512Kbit deep QDR buffers