Performance of the beetle readout chip for LHCb
CERN REPORT 2001:5 (2001) 52-56
Abstract:
This paper details the development steps of the 128 channel pipelined readout chip Beetle, which is being designed for the silicon vertex detector, the inner tracker, the pile-up veto trigger and the RICH detectors(1) of LHCb. Section II. summarizes the Beetle chip architecture.Section III. shows the key measurements on the first chip version (Beetle 1.0) which drove the design changes for the Beetle 1.1. First performance data of the new chip is presented in section IV., while an outlook on the future test and development of the chip are given in section V.Measurement of J/psi and psi(2S) polarization in pp collisions at sqrt[s] = 1.8 TeV.
Phys Rev Lett 85:14 (2000) 2886-2891
Abstract:
We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]
Angular and current-target correlations in deep inelastic scattering at HERA
European Physical Journal C 12:1 (2000) 53-68
Abstract:
Correlations between charged particles in deep inelastic e+ p scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation.Measurement of D*± production and the charm contribution to F2 in deep inelastic scattering at HERA
European Physical Journal C 12:1 (2000) 35-52
Abstract:
The production of D*± (2010) mesons in deep inelastic scattering has been measured in the ZEUS detector at HERA using an integrated luminosity of 37 pb-1. The decay channels D*+ → D0π+ (+c.c.), with D0 → K-π+ or D0 → K-π-π+π+, have been used to identify the D mesons. The e+p cross section for inclusive D*± production with 1 < Q2 < 600 GeV2 and 0.02 < y < 0.7 is 8.31±0.31(stat.)+0.30-0.50 (syst.) nb in the kinematic region 1.5 < pT(D*±) < 15 GeV and \η(D*±)\ < 1.5. Differential cross sections are consistent with a next-to-leading-order perturbative-QCD calculation when using charm-fragmentation models which take into account the interaction of the charm quark with the proton remnant. The observed cross section is extrapolated to the full kinematic region in pT(D*±) and η(D*±) in order to determine the charm contribution, Fcc̄2 (x, Q2), to the proton structure function. The ratio Fcc̄2/F2 rises from ≃10% at Q2 ≃ 1.8GeV2 to ≃30% at Q2 ≃130GeV2 for x values in the range 10-4 to 10-3.Measurement of high-Q2 charged-current e+p deep inelastic scattering cross sections at HERA
European Physical Journal C 12:3 (2000) 411-428