Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fluctuations of the gluon distribution from the small-x effective action   The computation of observables in high energy QCD involves an average over
stochastic semiclassical small-x gluon fields. The weight of various
configurations is determined by the effective action. We introduce a method to
study fluctuations of observables, functionals of the small-x fields, which
does not explicitly involve dipoles. We integrate out those fluctuations of the
gluon field under which a given observable is invariant. Thereby we obtain the
effective potential for that observable describing its fluctuations about the
saddle point. We determine explicitly the effective potential for the covariant
gauge gluon distribution both for the McLerran-Venugopalan (MV) model and for a
(non-local) Gaussian approximation for the small-x effective action. This
provides insight into the correlation of fluctuations of the number of hard
gluons versus their typical transverse momentum. We find that the spectral
shape of the fluctuations of the gluon distribution is fundamentally different
in the MV model, where there is a pile-up of gluons near the saturation scale,
versus the solution of the small-x JIMWLK renormalization group, which
generates essentially scale invariant fluctuations above the absorptive
boundary set by the saturation scale.

13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys