# Light-Ion Collisions - Bridging Small and Large QCD Systems

- Institution: CERN
- Department: Theory Colloquia
- Speaker: Aleksas Mazeliauskas
- Year: 2025
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3021607)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

The first oxygen–oxygen and neon–neon collisions at the LHC this July have opened a new frontier in exploring hot and dense QCD matter. These light-ion systems bridge the gap between proton–proton and heavy-ion collisions. Over the past decade, experiments have revealed intriguing but sometimes puzzling results: signals of elliptic flow appear even in proton–proton collisions, whereas clear signs of jet quenching remain absent in small systems. The recent pO, OO, and NeNe runs enable precision tests of heavy-ion models in intermediate-size systems. Light-ion collisions probe the critical regime where nuclear structure, perturbative QCD, and quark–gluon plasma physics intersect. I will discuss what the first light-ion data reveal about the structure of the colliding nuclei, the applicability of hydrodynamics, and the onset of partonic energy loss in small systems.

This colloquium is part of the Light ion collisions at the LHC - 2025 workshop. .

0:00:00 Slide 1

0:01:59 Slide 2

0:04:23 Slide 3

0:06:37 Slide 4

0:07:48 Slide 5

0:09:07 Slide 6

0:10:34 Slide 7

0:11:48 Slide 8

0:13:00 Slide 9

0:14:40 Slide 10

0:15:52 Slide 11

0:18:11 Slide 12

0:20:18 Slide 13

0:21:50 Slide 14

0:22:56 Slide 15

0:23:59 Slide 16

0:25:27 Slide 17

0:27:16 Slide 18

0:29:42 Slide 19

0:31:28 Slide 20

0:33:38 Slide 21

0:34:47 Slide 22

0:36:14 Slide 23

0:39:01 Slide 24

0:40:46 Slide 25

## Lectures

1. [Light-Ion Collisions - Bridging Small and Large QCD Systems](https://invisiblenetwork.ai/learn/cern/3021607/79e68d752a30), 55 min (CERN's player)