Evidence for X(3872) in Pb-Pb Collisions and Studies of its Prompt Production at √ s N N = 5.02 TeV

Abstract

The first evidence for X(3872) production in relativistic heavy ion collisions is reported. The $X(3872)$ production is studied in lead-lead (Pb-Pb) collisions at a center-of-mass energy of $\sqrt {s_{NN}}$ 5.02 TeV per nucleon pair, using the decay chain $X(3872) → J/ψ π^+ π^− → μ^+ μ^- π^+ π^−$. The data were recorded with the CMS detector in 2018 and correspond to an integrated luminosity of 1.7 nb$^{-1}$. The measurement is performed in the rapidity and transverse momentum ranges $|y|< $ 1.6 and 15$ < p_T