# Quark Matter 2017

5-11 February 2017
Hyatt Regency Chicago
America/Chicago timezone

## Evidence for collective phenomena in pp collisions with CMS

8 Feb 2017, 11:40
20m
Regency A

### Regency A

Oral QCD in small systems

### Speaker

Zhenyu Chen (Rice University (US))

### Description

Observation of long-range ridge-like correlations in high-multiplicity pp collisions opened up new opportunities for exploring novel QCD dynamics in small collision systems. Based on data collected in 2015 and 2016 with the CMS detector at the LHC, the second-order ($v_{2}$) and third-order ($v_{3}$) azimuthal anisotropy harmonics of $K_{s}^{0}$, $\Lambda$ and inclusive charged particles are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For the first time in pp collisions, the $v_{2}$ signals are also extracted from multi-particle correlations, providing direct evidence of the collective nature of observed particle correlations. These results provide new insights on the origin of observed long-range correlations in pp collisions, and may shed light on how quantum fluctuations affect the proton structure at a very short time scale.

Collaboration CMS QCD in small systems

### Primary author

Zhenyu Chen (Rice University (US))