Evidence of shadowing in inelastic nucleon-nucleon cross section

Kari J. Eskola, Ilkka Helenius, Mikko Kuha, Hannu Paukkunen

Research output: Contribution to journalConference articleScientificpeer-review


The Glauber modeling plays a key role in centrality-dependent measurements of heavy-ion collisions. A central input parameter in Glauber models is the inelastic nucleon-nucleon cross section σinel which is nearly always taken from proton-proton measurements. At the LHC energies nn σinel depends on the QCD dynamics at small x and low interaction scales where the shadownn ing/saturation phenomena are expected to become relatively more important for larger nuclei than for the proton. Thus, σnninel e.g. in Pb+Pb collisions may well be lower than what is seen in proton-proton collisions. In this talk, we demonstrate how to use the recent W± and Z measurements as a "standard candle" to extract σnninel in Pb+Pb collisions. Our analysis - built on the ATLAS data, state-of-the-art NNLO QCD calculations and nuclear PDFs - indicate that at the LHC energies σinel in Pb+Pb collisions is suppressed relative to the proton-proton measurements by tens of nn percents. We demonstrate that this is in line with expectations from nuclear PDFs.

Original languageEnglish
Article number046
JournalProceedings of Science
Number of pages5
Publication statusPublished - 1 Sept 2021
MoE publication typeA4 Article in conference proceedings
EventInternational Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions - Austin, United States
Duration: 1 Jun 20206 Jun 2020
Conference number: 10

Fields of Science

  • 114 Physical sciences

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