Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Drell-Yan angular lepton distributions at small $x$ from TMD
  factorization   The Drell-Yan process is studied in the framework of TMD factorization in the
Sudakov region $s\gg Q^2\gg q_\perp^2$ corresponding to recent LHC experiments
with $Q^2$ of order of mass of Z-boson and transverse momentum of DY pair
$\sim$ few tens GeV. The DY hadronic tensors are expressed in terms of quark
and quark-gluon TMDs with ${1\over Q^2}$ and ${1\over N_c^2}$ accuracy. It is
demonstrated that in the leading order in $N_c$ the higher-twist
quark-quark-gluon TMDs reduce to leading-twist TMDs due to QCD equation of
motion. The resulting hadronic tensors depend on two leading-twist TMDs: $f_1$
responsible for total DY cross section, and Boer-Mulders function $h_1^\perp$.
The corresponding qualitative and semi-quantitative predictions seem to agree
with LHC data on five angular coefficients $A_0-A_4$ of DY pair production. The
remaining three coefficients $A_5-A_7$ are determined by quark-quark-gluon TMDs
multiplied by extra ${1\over N_c}$ so they appear to be relatively small in
accordance with LHC results.

7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol