Observation of multiplicity-dependent prompt ${\chi }_{c1}(3872)$ and $\psi (2S)$ production in $pp$ collisions

Abstract

The production of ${\chi }_{c1}(3872)$ and $\psi (2S)$ hadrons is studied as a function of charged particle multiplicity in $pp$ collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2 fb${}^{-1}$. For both states, the fraction that is produced promptly at the collision vertex is found to decrease as charged particle multiplicity increases. The ratio of ${\chi }_{c1}(3872)$ to $\psi (2S)$ cross-sections for promptly produced particles is also found to decrease with multiplicity, while no significant dependence on multiplicity is observed for the equivalent ratio of particles produced away from the collision vertex in $b$-hadron decays. This behavior is consistent with a calculation that models the ${\chi }_{c1}(3872)$ structure as a compact tetraquark. Comparisons with model calculations and implications for the binding energy of the ${\chi }_{c1}(3872)$ state are discussed.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2020-023.html (LHCb public pages)

References in corpus (7)

• PYTHIA 6.4 Physics and Manual
• Performance of the LHCb Vertex Locator
• Can the X(3872) be a 1^{++} four-quark state?
• QCD Sum Rules for the X(3872) as a mixed molecule-charmoniun state
• Measurements of $\psi (2S)$ and $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ production in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
• $X(3872)\to D\bar{D}\gamma$ decays and the structure of X(3872)
• Unquenched quark-model calculation of X(3872) electromagnetic decays

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