# Online Strangeness in Quark Matter Conference 2021

May 17 – 22, 2021
US/Eastern timezone

## Evidence for X(3872) Production in PbPb collisions and studies of its prompt production with CMS

May 18, 2021, 10:10 AM
20m
Room D (Zoom)

### Room D

#### Zoom

zoom co-host: Mriganka Mouli Mondal https://stonybrook.zoom.us/j/93238724142
Experimental talk

### Speaker

Yen-Jie Lee (Massachusetts Inst. of Technology (US))

### Description

The first evidence for X(3872) production in relativistic heavy ion collisions is reported. The X(3872) hadron is studied in PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair, using the decay chain $X(3872)\rightarrow J/\psi\pi\pi\rightarrow \mu^{+}\mu^{-}\pi^{+}\pi^{-}$ decay chain. The data were recorded with the CMS detector in 2018 and correspond to an integrated luminosity of 1.7/nb. The measurement is performed in the rapidity and transverse momentum ranges |y|<1.6 and 15< pT < 50 GeV. The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to psi(2S) yield ratio is found to be $\rho^{PbPb}= 1.08\pm 0.49(stat)\pm 0.52(syst)$, in contrast to typical values of 0.1 for pp collisions. This result provides a unique experimental input to theoretical models of the production mechanism and the nature of the X(3872) state. Future plan to exploit the Run 3 data is also presented in this talk.

Collaboration CMS

### Primary author

Serguei Petrushanko (M.V. Lomonosov Moscow State University (RU))