Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NLO $Q^2$-evolution of the nucleon's transversity distribution $h_1(x,
  Q^2)$   We present a calculation of the two-loop anomalous dimension for the
transversity distribution $h_1(x,Q^2)$, $\gamma^{h(1)}_n$, in the MS scheme of
the dimensional regularization. Because of the chiral-odd nature, $h_1$ does
not mix with the gluon distributions, and thus our result is the same for the
flavor-singlet and nonsinglet distributions. At small $n$ (moment of $h_1$),
$\gamma^{h(1)}_n$ is significantly larger than $\gamma^{f,g(1)}_n$ (the
anomalous dimension for the nonsinglet $f_1$ and $g_1$), but approaches
$\gamma^{f,g(1)}_n$ very quickly at large $n$, keeping the relation
$\gamma^{h(1)}_n > \gamma^{f,g(1)}_n$. This feature is in parallel to the
relation between the one-loop anomalous dimension for $f_1$ $(g_1)$ and $h_1$.
We also show that this difference in the anomalous dimension between $h_1$ and
$g_1$ leads to a drastic difference in the $Q^2$-evolution of those
distributions in the small $x$ region.

21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
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
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs