Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Challenges with Large Transverse Momentum in Semi-Inclusive Deeply
  Inelastic Scattering   We survey the current phenomenological status of semi-inclusive deep
inelastic scattering at moderate hard scales and in the limit of very large
transverse momentum. As the transverse momentum becomes comparable to or larger
than the overall hard scale, the differential cross sections should be
calculable with fixed order pQCD methods, while small transverse momentum (TMD
factorization) approximations should eventually break down. We find large
disagreement between HERMES and COMPASS data and fixed order calculations done
with modern parton densities, even in regions of kinematics where such
calculations should be expected to be very accurate. Possible interpretations
are suggested.

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The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
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
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs