Study of $\hat{I}\yen$ production and cold nuclear matter effects in pPb collisions at $\sqrt{s_{NN}}=5\mathrm{TeV}$

Abstract

Production of $\hat{I}\yen$ mesons in proton-lead collisions at a nucleon-nucleon centre-of-mass energy $\sqrt{s_{NN}}=5\mathrm{TeV}$ is studied with the LHCb detector. The analysis is based on a data sample corresponding to an integrated luminosity of $1.6{\mathrm{nb}}^{-1}$. The $\hat{I}\yen$ mesons of transverse momenta up to $15\mathrm{GeV}/c$ are reconstructed in the dimuon decay mode. The rapidity coverage in the centre-of-mass system is $1.5<y<4.0$ (forward region) and $-5.0<y<-2.5$ (backward region). The forward-backward production ratio and the nuclear modification factor for $\hat{I}\yen (1S)$ mesons are determined. The data are compatible with the predictions for a suppression of $\hat{I}\yen (1S)$ production with respect to proton-proton collisions in the forward region, and an enhancement in the backward region. The suppression is found to be smaller than in the case of prompt $J/\ddot{I}ˆ$ mesons.

21 pages, 3 figures, published to JHEP