Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Delta s density in a proton and unpolarized lepton - polarized proton
  scatterings   It is shown that the parity--violating deep--inelastic scatterings of
unpolarized charged leptons on polarized protons, $\ell^{\mp} + \vec P\to
\stackrel{\scriptscriptstyle(-)}{\nu_{\ell}} + X$, could provide a sensitive
test for the behavior and magnitude of the polarized strange--quark density in
a proton. Below charm threshold these processes are also helpful to uniquely
determine the magnitude of individual polarized parton distributions.

17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc