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

Gürpınar Güler, Eminevd.2023-03-092023-03-0920220177-798Xhttps://doi.org/10.1103/PhysRevLett.128.032001The 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 s(NN)=5.02 TeV per nucleon pair, using the decay chain X(3872) ? J/??+?? ? ?+???+??. 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 jyj < 1.6 and 15 < pT < 50 GeV=c. The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to ?2S yield ratio is found to be ?Pb-Pb = 1.08 0.49(stat) 0.52(syst), to be compared with typical values of 0.1 for pp collisions. This result provides a unique experimental input to theoretical models of the X(3872) production mechanism, and of the nature of this exotic state.enEvidence for X(3872) in Pb-Pb Collisions and Studies of its Prompt Production at root s(NN)=5.02 TeVArticle10.1103/PhysRevLett.128.0320012-s2.0-8512371039635119878Q2WOS:000748799800002Q1