First Study of Exclusive Production of Multi-Hadron Final States in Ultraperipheral Collisions

TL;DR

This paper discusses the first measurements of exclusive multi-hadron final states in ultra-peripheral collisions, aiming to explore QCD phenomena and resonance structures with upgraded detector capabilities.

Contribution

It presents the ALICE collaboration's plans and preliminary results for studying multi-pion and charmonium decay channels in ultra-peripheral collisions using Run 3 data.

Findings

Evidence for two resonances in four-pion photoproduction

Enhanced detector capabilities enable new multi-hadron studies

Probing gluonic matter dynamics through exclusive processes

Abstract

The study of exclusive photoproduction of multi-hadron final states in ultra-peripheral collisions (UPCs) provides a unique avenue to explore quantum chromodynamics (QCD) and the nature of resonances emerging from gluonic interactions. The ALICE Collaboration has recently performed measurements of exclusive four-pion photoproduction using Run 2 data, favoring the presence of two resonances. However, the underlying nature of these resonances remains poorly understood. The enhanced capabilities of the ALICE detector during Run 3 open new opportunities for the study of multi-pion final states, including four and six-pion systems, and processes involving charmonium decays into four-hadron final states. These studies provide an invaluable way to probe the dynamics of highly dense gluonic matter and the interplay between resonant and non-resonant contributions in hadronic systems. In this paper, we outline the ALICE program focused on these analyses.