Search for jet quenching effects in high-multiplicity proton-proton collisions at $sqrt{s} = 13~rm{TeV}$

Abstract

The ALICE Collaboration presents results of a search for jet quenching effects in high-particle multiplicity pp collisions at $\sqrt{s}$ = 13 TeV. The analysis is based on the semi-inclusive acoplanarity spectrum of charged jets recoiling from a high-$p_{\rm{T}}$ trigger-track. Significant broadening and suppression of the recoil jet acoplanarity distribution is observed in high-multiplicity pp collisions in real data. However, similar features are also seen in events simulated by the PYTHIA 8 Monash Monte Carlo generator. The simulation reveals that the observed effects result from a bias induced by the ALICE high-multiplicity trigger, which enhances the probability to have a high-$p_{\rm{T}}$ recoil jet in the forward trigger detectors and which biases towards multi-jet final states.