Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Azimuthal asymmetries in unpolarized SIDIS and Drell-Yan processes: a
  case study towards TMD factorization at subleading twist   We consider the azimuthal distribution of the final observed hadron in
semi-inclusive deep-inelastic scattering and the lepton pair in the Drell-Yan
process. In particular, we focus on the $\cos \phi$ modulation of the
unpolarized cross section and on its dependence upon transverse momentum. At
low transverse momentum, for these observables we propose a factorized
expression based on tree-level approach and conjecture that the same formula is
valid in transverse-momentum dependent (TMD) factorization when written in
terms of subtracted TMD parton distributions. Our formula correctly matches
with the collinear factorization results at high transverse momentum, solves a
long-standing problem and is a necessary step towards the extension of the TMD
factorization theorems up to the subleading twist.

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The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con