Nucleon Energy Correlators for the Color Glass Condensate

Phys Rev Lett. 2023 May 5;130(18):181901. doi: 10.1103/PhysRevLett.130.181901.

Abstract

We demonstrate the recently proposed nucleon energy-energy correlator (NEEC) f_{EEC}(x,θ) can unveil the gluon saturation in the small-x regime in eA collisions. The novelty of this probe is that it is fully inclusive just like the deep-inelastic scattering (DIS), with no requirements of jets or hadrons but still provides an evident portal to the small-x dynamics through the shape of the θ distribution. We find that the saturation prediction is significantly different from the expectation of the collinear factorization.