Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New study of the Boer-Mulders function: Implications for the quark and
  hadron transverse momenta   In series of papers the Boer-Mulders function for a given quark flavour has
been extracted: (i) from data on semi-inclusive deep inelastic scattering,
using the simplifying, but theoretically inconsistent, assumption that it is
proportional to the Sivers function for each quark flavour and (ii) from data
on Drell-Yan reactions. In earlier papers, using the semi-inclusive deep
inelastic COMPASS deuteron data on the $\langle\cos\phi_h\rangle$ and
$\langle\cos 2 \phi_h\rangle$ asymmetries, we extracted the collinear
$x_{_{\!B}}$ dependence of the Boer-Mulders function for the sum of the valence
quarks $Q_V=u_V + d_V$ using a small number of model dependent assumptions and
found a significant disagreement with the analysis in (i). In the present
paper, we provide a more complete analysis of the semi-inclusive deep inelastic
scattering reaction, including a discussion of higher twist and
interaction-dependent terms, and also a comparison with the Boer-Mulders
function extracted from data on the Drell-Yan reaction. We confirm that the
proportionality relation of the BM function to the Sivers function, for each
quark flavour, fails badly, but find that it holds rather well if applied to
the nonsinglet valence-quark combination, $Q_V$. We also find good agreement
with the results of the Drell-Yan analysis. Furthermore, we obtain interesting
information on the quark transverse momentum densities in the nucleon and on
the hadron transverse momentum dependence in quark fragmentation.

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The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas
20
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: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: stat
3
The categories of this paper are: physics
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn