Measurement of forward $\rm Z\rightarrow e^+e^-$ production at $\sqrt{s}=8$ TeV

CERN-LHC. A measurement of the cross-section for Z-boson production in the forward region of pp collisions at 8TeV centre-of-mass energy is presented. The measurement is based on a sample of $rm Zrightarrow e^+e^-$ decays reconstructed using the LHCb detector, corresponding to an integrated luminosity of 2.0fb$^{-1}$. The acceptance is defined by the requirements $2.020$GeV for the pseudorapidities and transverse momenta of the leptons. Their invariant mass is required to lie in the range 60-120 GeV. The cross-section is determined to be $$ sigma({rm ppto Zto e^+e^-})=93.81pm0.41({rm stat})pm1.48({rm syst})pm1.14({rm lumi});{rm pb},,$$ where the first uncertainty is statistical and the second reflects all systematic effects apart from that arising from the luminosity, which is given as the third uncertainty. Differential cross-sections are presented as functions of the Z-boson rapidity and of the angular variable $phi^*$, which is related to the Z-boson transverse momentum.