Orateur
Description
The first observation of the simultaneous production of two $\rm{J}/\psi$ mesons in proton-nucleus collisions will be presented. The analysis is based on a data sample recorded at a nucleon-nucleon center-of-mass energy of 8.16 TeV by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 174.6 $\rm{nb}^{-1}$. The $\rm{J}/\psi$ mesons are reconstructed in their $\mu^+\mu^-$ decay channel for transverse momenta $p_{\rm{T}} > 6.5$ GeV and rapidity $|y| < 2.4$. The measured inclusive fiducial cross section $\sigma(\rm{pPb} \to \rm{J}/\psi \rm{J}/\psi + X)$ will be compared to perturbative quantum chromodynamics predictions at next-to-leading-order accuracy, including nuclear parton densities effects, for the production of two $\rm{J}/\psi$ mesons in single- (SPS) and double- (DPS) parton scatterings. A fit of the data to the expected $\rm{pPb} \to \rm{J}/\psi \rm{J}/\psi + X$ SPS and DPS kinematic distributions of the two $\rm{J}/\psi$ mesons will provide new constraints on the effective DPS cross section of $\sigma_{\text{eff}}$, related to the transverse distribution of partons in the proton.
