P. Conde

The performance of the HERA-B RICH at high track densities

Abstract The performance of the ring imaging Cherenkov counter (RICH) for the HERA-B experiment has been evaluated. The measured values of the basic parameters such as the number of detected photons per ring and Cherenkov angle resolution are found to agree with a priori estimates. Also at higher track densities, the detector is capable of identifying individual rings. Particle identification has been achieved by determining the momentum from tracks in the vertex detector and main tracking system, hits in the electromagnetic calorimeter and track directions as measured by the RICH.

Improved measurement of the bb production cross section in 920 GeV fixed-target proton-nucleus collisions

A new measurement of the b-bbar production cross section in 920 GeV proton-nucleus collisions is presented by the HERA-B collaboration. The b-bbar production is tagged via inclusive bottom quark decays into J/psi mesons, by exploiting the longitudinal separation of J/psi->ll decay vertices from the primary proton-nucleus interaction point. Both e+e- and mu+mu- channels are reconstructed, for a total of 83 +- 12 inclusive b->J/psi X events found. The combined analysis yields a b-bbar to prompt J/psi cross section ratio of

Using ASD8 as readout of multianode photomultipliers for single photoelectron discrimination in the HERA-B RICH detector

{\frac{{\Delta\sigma(bbbar)}}{{\Delta\sigma_{\jpsi}}}} = 0.032\pm 0.005 \stat \pm 0.004 \sys

The HERA-B ring imaging Cherenkov counter

measured in the x_f acceptance (-0.35 <x_f <0.15), extrapolated to

Production of the charmonium states Χc1 and Χc2 in proton nucleus interactions at s = 41.6 GeV

\sigma(bbbar) = 14.9 \pm 2.2 \stat \pm 2.4 \sys

Search for the Flavor-Changing Neutral Current Decay D 0 ! + with the HERA-B Detector

nb/nucleon in the total phase space.

K ∗0 and φ meson production in proton-nucleus interactions at √ s =4 1. 6G eV

Abstract ASD8 is the analog front end chosen to read out the photodetectors of the HERA-B RICH. A test of 1791 boards was performed to study which were the best operating conditions, to make a quality assessment and to optimize the distribution of the boards on the RICH focal plane. Nevertheless, some drawbacks are apparent when a board designed for tracker detectors is employed to convert a photomultiplier signal.