Evidence for X(3872) in Pb-Pb Collisions and Studies of its Prompt Production at √ s N N = 5.02 TeV
A. M. Sirunyan, A. Tumasyan, W. Adam, Federico Ambrogi, T. Bergauer, M. Dragicevic, J. Erö, A. Escalante Del Valle, M. Flechl, Wit, Adinda, M. Jeitler, N. Krammer, I. Krätschmer, D. Liko, T. Madlener, I. Mikulec, N. Rad, J. Schieck, R. Schöfbeck, M. Spanring, W. Waltenberger, C.-E. Wulz, M. Zarucki, V. Drugakov, V. Mossolov, J. Suarez Gonzalez, M. R. Darwish, E. A. De Wolf, D. Di Croce, X. Janssen, T. Kello, A. Lelek
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