Prompt and non-prompt $$\hbox {J}/\psi $$ J / ψ production and nuclear modification at mid-rapidity in p–Pb collisions at $$\mathbf{\sqrt{{ s}_{\text {NN}}}= 5.02}$$

Abstract

A measurement of beauty hadron production at mid-rapidity in proton-lead collisions at a nucleon-nucleon centre-of-mass energy √ s NN = 5.02 TeV is presented. The semi-inclusive decay channel of beauty hadrons into J/ψ is considered, where the J/ψ mesons are reconstructed in the dielectron decay channel at mid-rapidity down to transverse momenta of 1.3 GeV/c. The bb production cross section at mid-rapidity, dσ bb /dy, and the total cross section extrapolated over full phase space, σ bb , are obtained. This measurement is combined with results on inclusive J/ψ production to determine the prompt J/ψ cross sections. The results in p-Pb collisions are then scaled to expectations from pp collisions at the same centre-of-mass energy to derive the nuclear modification factor R pPb , and compared to models to study possible nuclear modifications of the production induced by cold nuclear matter effects. R pPb is found to be smaller than unity at low p T for both J/ψ coming from beauty hadron decays and prompt J/ψ .

Centrality dependence of J/ψ and ψ(2S) production and nuclear modification in p-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ = 8.16 TeV

“…The suppression at midrapidity is compatible with the one at forward y, while at backward y, i.e. in the Pb-going direction, no suppression of the J/ψ yields is observed [25,28,31]. Interestingly, the ψ(2S) appears to be more suppressed than the J/ψ at both forward and backward rapidity [26].…”

“…Cold nuclear matter effects are typically investigated using proton-nucleus collisions, where the formation of the QGP is not expected. At the LHC, the production of quarkonia was extensively studied in p-Pb collisions at a centre-of-mass energy per nucleon pair √ s NN = 5.02 TeV by the ALICE [25][26][27][28][29][30][31], ATLAS [32], CMS [33,34], and LHCb [35][36][37] collaborations. In the charmonium sector, a significant suppression of J/ψ yields is observed at forward rapidity y, i.e.…”

J/ψ production as a function of charged-particle multiplicity in p-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ = 8.16 TeV

“…The centralitydifferential measurements at √ s NN = 5.02 TeV [23] of the nuclear modification factor, p T and p 2 T , corresponding to relative multiplicities of at most 2.5 times the average one, can also be described by these models. The contribution from beauty-quark decays to the inclusive J/ψ yield amounts to ∼ 10% [57]. It is not expected to affect significantly these results, since a similar trend was observed for prompt and non-prompt J/ψ as a function of the charged-particle pseudorapidity density in pp collisions [30].…”

Quarkonium propagation in the quark–gluon plasma

“…Excited states of quarkonia can feed-down to the lower energy states after formation. CNM effects (see [160][161][162][163][164][165][166][167][168][169][170][171][172][173][174][175] for experimental constraints) modify the initial production rates in AA collisions.…”