Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Kinematics of Deep Inelastic Scattering in the Presence of Initial
  State Radiation   Initial state radiation (ISR) in deep inelastic scattering of charged leptons
on nucleons can lead to substantial shifts in the reconstruction of $Q^2$ and
the scaling variables $x$ and $y$. By measuring at least three out of the four
variables: energy and production angle of the lepton and the hadron system, the
energy of the ISR photon emitted under zero degrees can be determined. The ISR
effect is illustrated for experimentation at HERA with different methods of
kinematic reconstruction.

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
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat