The study on the structure of exotic states ${\chi }_{c1}(3872)$ via beauty-hadron decays in $pp$ collisions at $\sqrt{s}=8\mathrm{TeV}$

Abstract

A dynamically constrained phase-space coalescence (DCPC) model was introduced to study the exotic state ${\chi }_{c1}(3872)$ yield for three possible structures: tetraquark state, nuclear-like state, and molecular state respectively, where the hadronic final states generated by the parton and hadron cascade model (PACIAE). The ${\chi }_{c1}(3872)$/$\psi (2S)$ cross-section ratio from beauty-hadron decays (non-prompt) based on the ${\chi }_{c1}(3872)$ or $\psi (2S)\to J/\psi {\pi }^{+}{\pi }^{-}$ bound state in the decay chains as a function of charged-particle multiplicity and transverse momentum in $pp$ collisions at $\sqrt{s}=8\mathrm{TeV}$ are calculated. A tetraquark state scenario from PACIAE+DCPC model shows better agreement with the LHCb and ATLAS measurements for the non-prompt ${\chi }_{c1}(3872)$/$\psi (2S)$ cross-section ratio distributions, indicating that the ${\chi }_{c1}(3872)$ is more likely to be a compact tetraquark state.