Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sivers effect and the single spin asymmetry A_N in p(transv. pol.) p -->
  h X processes   The single spin asymmetry A_N, for large P_T single inclusive particle
production in p(transv. pol.) p collisions, is considered within a generalised
parton model and a transverse momentum dependent factorisation scheme. The
focus is on the Sivers effect and the study of its potential contribution to
A_N, based on a careful analysis of the Sivers functions extracted from
azimuthal asymmetries in semi-inclusive deep inelastic scattering processes. It
is found that such Sivers functions could explain most features of the A_N
data, including some recent STAR results which show the persistence of a non
zero A_N up to surprisingly large P_T values.

9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol