The first observation of Z boson production in proton-lead collisions at a centre-of-mass energy per proton-nucleon pair of snn = 5 TeV is presented. The data sample corresponds to an integrated luminosity of 1.6 nb-1 collected with the LHCb detector. The Z candidates are reconstructed from pairs of oppositely charged muons with pseudorapidities between 2.0 and 4.5 and transverse momenta above 20GeV/c. The invariant dimuon mass is restricted to the range 60 — 120GeV/c. The Z production cross-section is measured to be σz→µ+ µ- (fwd) = 13.5+5.4 -4.0(stat.) ± 1.2(syst.) nb in the direction of the proton beam and σz→µ+ µ- (bwd) = 10.7+8.4 -5.1(stat.) ± 1.0(syst.) nb in the direction of the lead beam, where the first uncertainty is statistical and the second systematic.
Observation of Z production in proton-lead collisions at LHCb
R. Cardinale;FONTANELLI, FLAVIO;PATRIGNANI, CLAUDIA;PETROLINI, ALESSANDRO;
2014-01-01
Abstract
The first observation of Z boson production in proton-lead collisions at a centre-of-mass energy per proton-nucleon pair of snn = 5 TeV is presented. The data sample corresponds to an integrated luminosity of 1.6 nb-1 collected with the LHCb detector. The Z candidates are reconstructed from pairs of oppositely charged muons with pseudorapidities between 2.0 and 4.5 and transverse momenta above 20GeV/c. The invariant dimuon mass is restricted to the range 60 — 120GeV/c. The Z production cross-section is measured to be σz→µ+ µ- (fwd) = 13.5+5.4 -4.0(stat.) ± 1.2(syst.) nb in the direction of the proton beam and σz→µ+ µ- (bwd) = 10.7+8.4 -5.1(stat.) ± 1.0(syst.) nb in the direction of the lead beam, where the first uncertainty is statistical and the second systematic.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.