Triple Prompt $J/\psi$ Hadroproduction as a Hard Probe of Multiple-Parton Scatterings

We propose that the process of triple prompt $J/\psi$ hadroproduction is a very clean hard probe of multiple-parton scatterings at high-energy hadron colliders, especially the least known triple-parton scattering. A first complete study is carried out by considering single-, double-, and triple-parton scatterings coherently. Our calculation shows that it is a golden channel to probe double- and triple-parton scatterings, as the single-parton scattering is strongly suppressed. The predictions of the (differential) cross sections in proton-proton collisions at the LHC and future higher-energy hadron colliders are given. Our study shows that its measurement is already feasible with the existing data collected during the period of the LHC run 2. A method is proposed to extract the triple-parton scattering contribution, and therefore it paves a way to study the possible triple-parton correlations in a proton.

Figure 1

Typical Feynman diagrams for triple $J/\psi$ hadroproduction via (a) SPS, (b) DPS, and (c) TPS processes.

Figure 2

Cross section $\sigma (pp\to 3J/\psi )\times {\text{Br}}^3(J/\psi \to {\mu }^{+}{\mu }^{-})$ (in femtobarn) dependence of the minimal transverse momentum cut $P_T>P_{T,\min }$ among three $J/\psi$’s at $\sqrt{s}=13\mathrm{TeV}$ and within the rapidity interval $|y_{J/\psi }|<2.4$. The horizontal dashed lines are the expected 100 events under targeted integrated luminosities.

Figure 3

Cross section $\sigma (pp\to 3J/\psi )\times {\text{Br}}^3(J/\psi \to {\mu }^{+}{\mu }^{-})$ (in femtobarn) dependence of the minimal rapidity gap cut $|\mathrm{\Delta }y|>|\mathrm{\Delta }y{|}_{\min }$ among three $J/\psi$’s at $\sqrt{s}=13\mathrm{TeV}$. The horizontal dashed lines are the expected 100 events under targeted integrated luminosities.