Study of ϒ $$ \varUpsilon $$ production and cold nuclear matter effects in pPb collisions at s NN $$ \sqrt{s_{NN}} $$ = 5 TeV

Abstract

Production of Υ mesons in proton-lead collisions at a nucleon-nucleon centreof-mass energy √ s NN = 5 TeV is studied with the LHCb detector. The analysis is based on a data sample corresponding to an integrated luminosity of 1.6 nb −1 . The Υ mesons of transverse momenta up to 15 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 Υ(1S) mesons are determined. The data are compatible with the predictions for a suppression of Υ(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/ψ mesons.

Study of prompt D 0 meson production in pPb collisions at s N N = 5 $$ \sqrt{s_{\mathrm{N}\;\mathrm{N}}}=5 $$ TeV

“…Recently, CNM effects were measured in pPb collisions at the LHC for quarkonium and heavy flavour production [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The ALICE experiment studied D meson productions in pPb collisions [25,27,31] at √ s NN = 5 TeV in the region −0.96 < y * < 0.04, where y * is the rapidity of the D meson defined in the centre-of-mass system of the colliding nucleons.…”

Prospects for Quarkonium Measurements in p–A and A–A Collisions at the LHC

“…This model could also reproduce the main features of the available data for J/ψ [34,32,35] and ϒ (1S) [36,37] production at low p T , where the strongest modifications are observed both in data as well as in the model. In summary, a variety of models exists and there is at the moment no conclusive and broadly accepted interpretation of the available data.…”

“…The use of nuclear parton distribution functions (nPDF's) even available at NLO [28,29,30,31], in practice most calculations employ the EPS09 parameterisations [29], can at least approximately account for the measured J/ψ [32,33,34,35] and the ϒ (1S) [36,37] nuclear modification factors. Nevertheless, the currently available gluon distributions in the relevant region of Bjorken-x suffer from large uncertainties already for the nucleon but even more for the nucleus in absence of lepton-ion collider data or other sensitive inputs.…”

“…The LHCb detector took data for the first time in 2013 in p-Pb collisions and contributed already significantly to the measurement of non-deconfinement effects in nuclear collisions in the quarkonium sector [32,36,44]. The detector is fast, features a HLT with an input rate of 1 MHz in pp collisions and a large event rate storage capability of about 10 kHz.…”

Results from pPb collisions and prospects for heavy-ion interactions with LHCb

“…Due to the asymmetric beam configuration, the LHCb acceptance corresponds to 1.5 < y < 4.0 (−5.0 < y < −2.5) for the forward (backward) configuration. Results on J/ψ [6] and Υ [7] production and CNM effects are reported in the following.…”