N. Semprini-Cesari

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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)
We have searched for Theta+(1540) and Xi(--)(1862) pentaquark candidates in proton-induced reactions on C, Ti, and W targets at midrapidity and square root of s = 41.6 GeV. In 2 x 10(8) inelastic events we find no evidence for narrow (sigma approximately 5 MeV) signals in the Theta+ --> pK0(S) and Xi(--) --> Xi- pi- channels; our 95% C.L. upper limits (UL)(More)
The mid-rapidity (dσpN/dy at y=0) and total (σpN ) production cross sections of J/ψ mesons are measured in proton-nucleus interactions. Data collected by the HERA-B experiment in interactions of 920 GeV/c protons with carbon, titanium and tungsten targets are used for this analysis. The J/ψ mesons are reconstructed by their decay into lepton pairs. The(More)
We report on a search for the flavor-changing neutral current decay D0 → μ+μ− using 50 × 106 events recorded with a dimuon trigger in interactions of 920GeV protons with nuclei by the HERA-B experiment. We find no evidence for such decays and set a 90% confidence level upper limit on the branching fraction B(D0 → μ+μ−) < 2.0 × 10−6.
The proton-nucleon cross section ratio R = Br(Υ → l+l−) · dσ(Υ)/dy|y=0 /σ(J/ψ) has been measured with the HERA-B spectrometer in fixed-target proton-nucleus collisions at 920 GeV proton beam energy corresponding to a proton-nucleon cms energy of √ s = 41.6 GeV. The combined results for the decay channels Υ → e+e− and Υ → μ+μ− yield a ratio R = (9.0±2.1)(More)
A measurement of the polarization of Λ and Λ baryons produced in pC and pW collisions at √ s = 41.6 GeV has been performed with the HERA B spectrometer. The measurements cover the kinematic range of 0.6 GeV/c < p⊥ < 1.2 GeV/c in transverse momentum and −0.15 < xF < 0.01 in Feynman-x. The polarization results from the two different targets agree within the(More)
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