# First measurement of the energy and Mandelstam-t dependence of incoherent J/ψ photonuclear production with ALICE

- Institution: CERN
- Department: LHC Seminar
- Speaker: Vendulka Humlova
- Year: 2025
- Language: English
- Subjects: Earth and environment
- Source: [CERN](https://videos.cern.ch/record/3022273)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Tweens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

Quantum chromodynamics predicts that at sufficiently high energies the gluon density inside hadrons enters a regime, known as gluon saturation, where gluon splitting and recombination reach a dynamic equilibrium. Diffractive photoproduction of J/ψ mesons is a particularly sensitive probe of this phe- nomenon, since it directly couples to the gluon distribution of the nucleus. With its unique coverage of photon–nucleon center-of-mass energies from about 20 to 800 GeV, the ALICE detector can study the energy dependence of J/ψ production across three orders of magnitude in Bjorken-x.

In this talk, I will present the latest ALICE measurements of the energy dependence of incoher- ent photonuclear J/ψ production in Pb–Pb ultra-peripheral collisions at √sNN = 5.02 TeV, analyzed in three Mandelstam-t intervals. While low-|t| production reflects the average gluon density in nu- clei, higher-|t| values probe gluon fluctuations at smaller spatial scales. The observed suppression of the cross-section growth with energy at large |t| relative to low |t| provides new evidence of gluon saturation–like dynamics, offering unprecedented constraints on models of QCD in the high-energy limit.

Refreshments will be served at 10h30

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## Lectures

1. [First measurement of the energy and Mandelstam-t dependence of incoherent J/ψ photonuclear production with ALICE](https://invisiblenetwork.ai/learn/cern/3022273/6225ab6d811d), 46 min (CERN's player)