Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exclusive rho^0 production in deep inelastic scattering at HERA   Exclusive rho^0 electroproduction at HERA has been studied with the ZEUS
detector using 120 pb^{-1} of integrated luminosity collected during 1996-2000.
The analysis was carried out in the kinematic range of photon virtuality 2 <
Q^2 < 160 GeV$^2, and gamma^* p centre-of-mass energy 32 < W < 180 GeV. The
results include the Q^2 and W dependence of the gamma^* p --> rho^0 p cross
section and the distribution of the squared-four-momentum transfer to the
proton. The helicity analysis of the decay-matrix elements of the rho^0 was
used to study the ratio of the gamma^* p cross section for longitudinal and
transverse photon as a function of Q^2 and W. Finally, an effective Pomeron
trajectory was extracted. The results are compared to various theoretical
predictions.

35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con