Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Q^2-Dependence of the Drell-Hearn-Gerasimov integral   The energy and four-momentum (Q^2) dependence of the photo-absorption cross
section on the proton is calculated for helicity -1/2 and -3/2 states. An
effective Lagrangian model is used, formulated in terms of meson and baryon
degrees of freedom, which obeys crossing symmetry, unitarity, Lorentz and gauge
invariance. The difference in the cross sections for the two helicity states,
the Drell-Hearn-Gerasimov integral $I_{DHG}(Q^2)$, is evaluated at different
$Q^2$. We find that at small momentum transfer the absolute value of
$I_{DHG}(Q^2)$ first increases to reach a maximum at $Q^2 \approx 0.05 GeV^2$
before decreasing at higher $Q^2$.

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The categories of this paper are: q-fin
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th