Energy momentum conservation effects on two-particle correlation functions

TL;DR

This paper investigates how energy-momentum conservation influences two-particle correlation functions in proton-proton and heavy ion collisions, providing a new method to account for baseline shifts caused by these effects.

Contribution

It introduces a novel technique, based on energy-momentum conservation, to quantify long-range correlations affecting two-particle correlation functions.

Findings

Baseline of correlation functions can be modeled with the new technique.

Monte Carlo simulations support the effectiveness of the method.

Energy-momentum conservation significantly impacts correlation measurements.

Abstract

Two particle correlations are used to extract information about the characteristic size of the system in proton-proton and heavy ion collisions. The size of the system can be extracted from the Bose-Einstein quantum mechanical effect for identical particles. However there are also long range correlations that shift the baseline of the correlation function from the expected flat behavior. A possible source of these correlations is the conservation of energy and momentum, especially for small systems, where the energy available for particle production is limited. A new technique, first used by the STAR collaboration, of quantifying these long range correlations using energy-momentum conservation considerations is presented in this talk. Using Monte Carlo simulations of proton-proton collisions at 900 GeV, it is shown that the baseline of the two particle correlation function can be described using this technique.