Femtoscopy with identified hadrons in pp, pPb, and PbPb collisions in CMS

TL;DR

This study uses the CMS detector to analyze short-range correlations of identified hadrons in various collision systems, revealing insights into quantum effects, resonance decays, and collective behavior across different energies and multiplicities.

Contribution

It provides a comprehensive femtoscopic analysis of identified hadron correlations in pp, pPb, and PbPb collisions, highlighting system-independent features of the radii and correlation functions.

Findings

Radiii range from 1 to 5 fm, highest in high-multiplicity pPb.

Radii decrease with increasing transverse pair momentum.

Correlation characteristics largely factorize and are system-independent.

Abstract

Short range correlations of identified charged hadrons in pp ($\sqrt{s} =$ 0.9, 2.76, and 7 TeV), pPb ($\sqrt{s_{_\mathrm{NN}}} =$ 5.02 TeV), and peripheral PbPb collisions ($\sqrt{s_{_\mathrm{NN}}} =$ 2.76 TeV) are studied with the CMS detector at the LHC. Charged pions, kaons, and protons at low momentum and in laboratory pseudorapidity $|\eta| < 1$ are identified via their energy loss in the silicon tracker. The two-particle correlation functions show effects of quantum statistics, Coulomb interaction, and also indicate the role of multi-body resonance decays and mini-jets. The characteristics of the one-, two-, and three-dimensional correlation functions are studied as a function of transverse pair momentum, $k_\text{T}$, and the charged-particle multiplicity of the event. The extracted radii are in the range 1-5 fm, reaching highest values for very high multiplicity pPb, also for similar multiplicity PbPb collisions, and decrease with increasing $k_\text{T}$. The dependence of radii on multiplicity and $k_\text{T}$ largely factorizes and appears to be insensitive to the type of the colliding system and center-of-mass energy.