Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of transversity in deep-inelastic scattering by polarized
  protons   Single-spin asymmetries for pions and charged kaons are measured in
semi-inclusive deep-inelastic scattering of positrons and electrons off a
transversely nuclear-polarized hydrogen target. The dependence of the cross
section on the azimuthal angles of the target polarization (phi_S)and the
produced hadron (phi) is found to have a substantial sin(phi+phi_S) modulation
for the production of pi+, pi- and K+. This Fourier component can be
interpreted in terms of non-zero transversity distribution functions and
non-zero favored and disfavored Collins fragmentation functions with opposite
sign. For pi0 and K- production the amplitude of this Fourier component is
consistent with zero.

34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
2
The categories of this paper are: math
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom