Probing proton fluctuations with asymmetric rapidity correlations

TL;DR

This paper links intrinsic proton saturation momentum fluctuations to asymmetric rapidity correlations, proposing a model that connects experimental measurements to the variance of these fluctuations, providing insights into proton structure.

Contribution

It introduces a simple model that connects the asymmetric component of rapidity correlations to the variance of proton saturation scale fluctuations, offering a new probe for proton structure.

Findings

The variance of proton saturation scale fluctuations is estimated to be 0.5-1.

The model successfully describes the ATLAS measurements of rapidity correlations.

Asymmetric rapidity correlations are sensitive probes of proton fluctuations.

Abstract

Intrinsic fluctuations of the proton saturation momentum generate asymmetric rapidity distributions on an event-by-event basis. We argue that the asymmetric component, $\left<a_1^2\right>$, of the orthogonal polynomial decomposition of the two-particle rapidity correlation function is a sensitive probe to this distribution of fluctuations. We present a simple model connecting the experimentally measured $\left<a_1^2\right>$ to the variance, $\sigma$, of the distribution of the logarithm of the proton saturation scale. We find that $\sigma\approx 0. 5-1$ describes the asymmetric component of the rapidity correlations recently measured by the ATLAS collaboration.