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

A measurement of beauty hadron production at mid-rapidity in proton-lead collisions at a nucleon–nucleon centre-of-mass energy $\sqrt{s_\text {NN}}=5.02$ TeV is presented. The semi-inclusive decay channel of beauty hadrons into $\hbox {J}/\psi $ is considered, where the $\hbox {J}/\psi $ mesons are reconstructed in the dielectron decay channel at mid-rapidity down to transverse momenta of 1.3 GeV/c. The $\hbox {b}\bar{\hbox {b}}$ production cross section at mid-rapidity, $\hbox {d}\sigma _{\hbox {b}\bar{\hbox {b}}}/\hbox {d}y$ , and the total cross section extrapolated over full phase space, $\sigma _{\text {b}\bar{\text {b}}}$ , are obtained. This measurement is combined with results on inclusive $\hbox {J}/\psi $ production to determine the prompt $\hbox {J}/\psi $ 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 $R_{\text {pPb}}$ , and compared to models to study possible nuclear modifications of the production induced by cold nuclear matter effects. $R_{\text {pPb}}$ is found to be smaller than unity at low $p_{\mathrm{T}}$ for both $\hbox {J}/\psi $ coming from beauty hadron decays and prompt $\hbox {J}/\psi $ .