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 ffiffiffiffiffiffiffiffi sNN p ¼5.02TeVper nucleon pair, using the decay chain Xð3872Þ → J=ψπþπ− → μþμ−πþπ−. 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 < 50 GeV=c. The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to ψ2S yield ratio is found to be ρPb-Pb ¼ 1.08 0.49ðstatÞ 0.52ðsystÞ, 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.
Evidence for X(3872) in Pb-Pb Collisions and Studies of its Prompt Production at sNN=5.02 TeV
Miniello, G.Membro del Collaboration Group
;
2022
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 ffiffiffiffiffiffiffiffi sNN p ¼5.02TeVper nucleon pair, using the decay chain Xð3872Þ → J=ψπþπ− → μþμ−πþπ−. 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 < 50 GeV=c. The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to ψ2S yield ratio is found to be ρPb-Pb ¼ 1.08 0.49ðstatÞ 0.52ðsystÞ, 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.| File | Dimensione | Formato | |
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