Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of gluon number fluctuations on photon - photon collisions at
  high energies   We investigate the effects of gluon number fluctuations on the total
$\gamma\gamma$, $\gamma^*\gamma^*$ cross sections and the photon structure
function $F_2^\gamma(x,Q^2)$. Considering a model which relates the
dipole-dipole and dipole-hadron scattering amplitudes, we estimate these
observables by using event-by-event and physical amplitudes. We demonstrate
that both analyses are able to describe the LEP data, but predict different
behaviours for the observables at high energies, with the gluon fluctuations
effects decreasing the cross sections. We conclude that the study of $\gamma
\gamma$ interactions can be useful to constrain the QCD dynamics.

18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg