Subfemtometer scale color charge correlations in the proton

Abstract

Color charge correlations in the proton at moderately small x ∼ 0.1 are extracted from its lightcone wave function. The charge fluctuations are far from Gaussian and they exhibit interesting dependence on impact parameter and on the relative transverse momentum (or distance) of the gluon probes. We provide initial conditions for small-x Balitsky-Kovchegov evolution of the dipole scattering amplitude with impact parameter andr ·b dependence, and with non-zero C-odd component due to three-gluon exchange. Lastly, we compute the (forward) Weizsäcker-Williams gluon distributions, including the distribution of linearly polarized gluons, up to fourth order in A + . The correction due to the quartic correlator provides a transverse momentum scale, q > ∼ 0.5 GeV, for nearly maximal polarization.

QCD thermalization: Ab initio approaches and interdisciplinary connections

“…We will now discuss other bulk observables in high energy nucleus-nucleus, hadron-nucleus, and hadron-hadron collisions that can help constrain the properties of saturated gluons and their early-time evolution. In the smaller systems, even if the system hydrodynamizes quickly, the large shape fluctuations of partons will provide insight into multi-parton correlations in the initial state [256]; understanding these from first principles is a challenging problem [624] that may also require the EIC to resolve.…”

Spin-dependent Pomeron and Odderon in elastic proton–proton scattering

“…Finally, it is of course necessary to extend the present calculation to finite momentum transfer t, in particular up to the 'dip' region of dσ/dt. The basic formulas are given in ( 37)-( 40), but we are missing models of the spin-independent and spin-dependent Pomeron and Odderon amplitudes at finite t (see for example [69,70] for a model of g 1,1 at finite impact parameter). They can also serve as an initial condition for the impact-parameter dependent BK equation to determine the energy dependence.…”

Sub-femtometer scale color charge fluctuations in a proton made of three quarks and a gluon

“…( 35) does indeed vanish when either q 1 , q 3 → 0 (see, also, refs. [33,34,45]). In what follows we consider the correction at O(g 5 ).…”