# Observation of $Z$ production in proton-lead collisions at LHCb

Abstract : The first observation of $Z$ boson production in proton-lead collisions at a centre-of-mass energy per proton-nucleon pair of $\sqrt{s_{NN}}=5~\text{TeV}$ is presented. The data sample corresponds to an integrated luminosity of $1.6~\text{nb}^{-1}$ 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 $20~\text{GeV}/c$. The invariant dimuon mass is restricted to the range $60-120~\text{GeV}/c^2$. The $Z$ production cross-section is measured to be \begin{eqnarray*} \sigma_{Z\to\mu^+\mu^-}(\text{fwd})&=&13.5^{+5.4}_{-4.0}\text{(stat.)}\pm1.2\text{(syst.)}~\text{nb} \end{eqnarray*} in the direction of the proton beam and \begin{eqnarray*} \sigma_{Z\to\mu^+\mu^-}(\text{bwd}) & =&10.7^{+8.4}_{-5.1}\text{(stat.)}\pm1.0\text{(syst.)}~\text{nb} \end{eqnarray*} in the direction of the lead beam, where the first uncertainty is statistical and the second systematic.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01005156
Contributor : Sabine Starita <>
Submitted on : Thursday, June 12, 2014 - 9:58:51 AM
Last modification on : Wednesday, September 16, 2020 - 4:26:35 PM

### Citation

R. Aaij, Y. Amhis, S. Barsuk, M. Borsato, O. Callot, et al.. Observation of $Z$ production in proton-lead collisions at LHCb. Journal of High Energy Physics, Springer, 2014, 09, pp.030. ⟨10.1007/JHEP09(2014)030⟩. ⟨in2p3-01005156⟩

Record views