Pseudorapidity and transverse momentum dependence of flow harmonics in pPb and PbPb collisions

TL;DR

This paper investigates how flow harmonics in high-multiplicity pPb and peripheral PbPb collisions depend on pseudorapidity and transverse momentum, using various correlation methods to analyze data from the CMS detector at the LHC.

Contribution

It provides a detailed analysis of flow harmonic dependence on pseudorapidity and transverse momentum, incorporating event plane decorrelation effects in pPb and PbPb collisions.

Findings

Event plane decorrelation explains most pseudorapidity dependence.

Flow harmonics vary with transverse momentum and pseudorapidity.

Different correlation methods yield consistent flow measurements.

Abstract

Measurements of azimuthal angular correlations are presented for high-multiplicity pPb collisions at $\sqrt{s_\mathrm{NN}}=$ 5.02 TeV and peripheral PbPb collisions at $\sqrt{s_\mathrm{NN}}=$ 2.76 TeV. The data used in this work were collected with the CMS detector at the CERN LHC. Fourier coefficients as functions of transverse momentum and pseudorapidity are studied using the scalar product method, 4-, 6-, and 8-particle cumulants, and the Lee-Yang zeros technique. The influence of event plane decorrelation is evaluated using the scalar product method and found to account for most of the observed pseudorapidity dependence.