Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analytic derivation of the leading-order gluon distribution function
  G(x,Q^2) = xg(x,Q^2) from the proton structure function F_2^p(x,Q^2)   We derive a second-order linear differential equation for the leading order
gluon distribution function G(x,Q^2) = xg(x,Q^2) which determines G(x,Q^2)
directly from the proton structure function F_2^p(x,Q^2). This equation is
derived from the leading order DGLAP evolution equation for F_2^p(x,Q^2), and
does not require knowledge of either the individual quark distributions or the
gluon evolution equation. Given an analytic expression that successfully
reproduces the known experimental data for F_2^p(x,Q^2) in a domain
x_min<=x<=x_max, Q_min^2<=Q^2<=Q_max^2 of the Bjorken variable x and the
virtuality Q^2 in deep inelastic scattering, G(x,Q^2) is uniquely determined in
the same domain. We give the general solution and illustrate the method using
the recently proposed Froissart bound type parametrization of F_2^p(x,Q^2) of
E. L. Berger, M. M. Block and C-I. Tan, PRL 98, 242001, (2007). Existing
leading-order gluon distributions based on power-law description of individual
parton distributions agree roughly with the new distributions for x>~10^-3 as
they should, but are much larger for x<~10^-3.

29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga