Observation of exotic $J/\psi\phi$ resonant structure in diffractive processes in proton-proton collisions

TL;DR

This paper reports the first observation of exotic $J/ar{ ext{psi}} ext{phi}$ resonant structures in diffractive proton-proton collisions at 13 TeV, confirming and discovering resonant states with high significance.

Contribution

It presents the first evidence of $J/ar{ ext{psi}} ext{phi}$ resonances in diffractive processes, including the observation of $ ext{chi}_{c0}(4500)$ and confirmation of $ ext{chi}_{c1}(4274)$.

Findings

Observation of $ ext{chi}_{c0}(4500)$ with over 6σ significance.

Confirmation of $ ext{chi}_{c1}(4274)$ with over 4σ significance.

Data disfavors nonresonant production, supporting resonant models.

Abstract

The first study of $J/\psi\phi$ production in diffractive processes in proton-proton collisions is presented. The study is based on an LHCb dataset recorded at centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5 fb$^{-1}$. The data disfavour a nonresonant $J/\psi\phi$ production but are consistent with a resonant model including several resonant states observed previously only in $B^+ \to J/\psi\phi K^+$ decays. The $\chi_{c0}(4500)$ state is observed with a significance over $6\sigma$ and the $\chi_{c1}(4274)$ is confirmed with a significance of more than $4\sigma$.