Husimi distribution for nucleon tomography

TL;DR

This paper introduces the QCD Husimi distribution as a positive, probabilistic phase space distribution for nucleons, enabling entropy definition and potential links to the Color Glass Condensate at small-x.

Contribution

It defines the QCD Husimi distribution for nucleons, providing a positive, interpretable phase space distribution and exploring its connection to small-x QCD physics.

Findings

Husimi distribution is better behaved and positive compared to Wigner distribution.

It allows for a probabilistic interpretation of nucleon structure.

Potential connection to Color Glass Condensate at small-x is discussed.

Abstract

We define the QCD Husimi distribution as the phase space distribution of partons inside the nucleon. Compared to the more well-known Wigner distribution, the Husimi distribution is better behaved and positive. It thus allows for a probabilistic interpretation and can be used to define the `entropy' of the nucleon as a measure of complexity of the partonic structure. A possible connection to the Color Glass Condensate approach at small-$x$ is also discussed.