R. Messi

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Measurement of ψ(2S) meson production in pp collisions at √ s = 7 TeV Abstract The differential cross-section for the inclusive production of ψ(2S) mesons in pp collisions at √ s = 7 TeV has been measured with the LHCb detector. The data sample corresponds to an integrated luminosity of 36 pb −1. The ψ(2S) mesons are reconstructed in the decay channels(More)
  • S Amato, D Carvalho, P Colrain, T Da Silva, J R T De Mello, L De Paula +494 others
  • 2000
This Technical Design Report is dedicated to Tom Ypsilantis. Tom conceived the Ring Imaging Cherenkov detectors for particle identification in LHCb and he made an inestimable contribution to the LHCb RICH project. Tom would have wished to see these detectors in operation. He was totally dedicated to the project. He will be missed by the RICH group for his(More)
The angular distributions and the partial branching fraction of the decay B0 → K*0 μ+ μ- are studied by using an integrated luminosity of 0.37  fb(-1) of data collected with the LHCb detector. The forward-backward asymmetry of the muons, A(FB), the fraction of longitudinal polarization, F(L), and the partial branching fraction dB/dq2 are determined as a(More)
We present recent results of an extensive aging test, performed at the CERN Gamma Irradiation Facility, on two bakelite Resistive Plate Chambers (RPC) detectors. With a method based on a model describing the behavior of an RPC exposed to a large particle flux, we have periodically measured the electrode resistivity r of the two detectors over 3 years. We(More)
Recent results of an aging test performed at the CERN Gamma Irradiation Facility on a single–gap RPC prototype developed for the LHCb Muon System are presented. The results are based on an accumulated charge of about 0.45 C/cm 2 , corresponding to about 4 years of LHCb running at the highest background rate. The performance of the chamber has been studied(More)
In the fixed energy environment of the e + e − collider DAΦNE, KLOE can measure the cross section of the process e + e − → hadrons as a function of the hadronic system energy using the radiative return method. At energies below 1 GeV, e + e − → ρ → π + π − is the dominating hadronic process. We report here on the status of the analysis of the process e + e(More)
Resistive plate chambers (RPC) are strong candidates for the outer regions of the LHCb muon detector. We have tested single-gap and dual-gap detectors built with low-resistivity phenolic plates ("9;10 cm) and operated in avalanche mode. Measurements have been performed over a wide range of beam intensities and on the GIF at CERN. The results are presented(More)
The production of Υ (1S), Υ (2S) and Υ (3S) mesons in proton-proton collisions at the centre-of-mass energy of √ s = 7 TeV is studied with the LHCb detector. The analysis is based on a data sample of 25 pb −1 collected at the Large Hadron Collider. The Υ mesons are reconstructed in the decay mode Υ → μ + μ − and the signal yields are extracted from a fit to(More)
The calibration and performance of the opposite-side flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been developed using simulated events and optimized and calibrated with B + → J /ψK + , B 0 → J /ψK * 0 and B 0 → D * − μ + ν μ decay modes with 0.37 fb −1 of data(More)
The design of the large drift chamber for KLOE reeects the experiment's aim of studying CP-violation in K decays. The KLOE drift chamber is cylindrical in shape, with a radius of about 2 m and a length of about 3.3 m, providing adequate path for K L decays. Spherical end walls which hold the tension of about 50,000 wires, have to be transparent to photons(More)