Multiplicity dependence of two-particle azimuthal correlations in pp collisions at the LHC

TL;DR

This paper investigates how two-particle azimuthal correlations vary with multiplicity in proton-proton collisions at different energies, providing insights into parton fragmentation and multiple parton interactions.

Contribution

It presents new measurements of di-hadron azimuthal correlations at multiple energies and multiplicities, comparing results with various event generator models.

Findings

Pair yields increase with multiplicity.

Data show agreement and discrepancies with PYTHIA and PHOJET models.

Insights into low transverse momentum parton fragmentation.

Abstract

We present the measurements of particle pair yields per trigger particle obtained from di-hadron azimuthal correlations in pp collisions at $\sqrt{s} = 0.9$, $2.76$, and $7$ TeV recorded with the ALICE detector. The yields are studied as a function of the charged particle multiplicity. Taken together with the single particle yields the pair yields provide information about parton fragmentation at low transverse momenta, as well as on the contribution of multiple parton interactions to particle production. Data are compared to calculations using the PYTHIA6, PYTHIA8, and PHOJET event generators.