Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transversely polarized Drell-Yan measurements at COMPASS   The exploration of the transverse spin structure of the nucleon by measuring
spin (in)dependent azimuthal asymmetries in semi-inclusive DIS (SIDIS) and in
Drell-Yan processes is one of the main objectives of the COMPASS experiment at
CERN (SPS, M2 beamline). During the first phase of the experiment (2002-2011) a
series of SIDIS measurements were performed, using a longitudinally polarized
muon beam impinging on transversely polarized $^6$LiD or NH$_3$ targets. As a
part of the COMPASS-II programme, in 2015 and 2018 the experiment performed
Drell-Yan measurements with a $\pi^-$ beam interacting with a transversely
polarized NH$_3$. The measurement of the Sivers and other azimuthal asymmetries
at the same hard scale in polarized SIDIS and Drell-Yan provides a unique
possibility to test predicted in QCD (pseudo-)universal features of transverse
momentum dependent parton distribution functions.

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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
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The categories of this paper are: supr-con
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The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics
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The categories of this paper are: alg-geom