Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dispersive analysis of low energy $\gamma^* N\rightarrow\pi N$ process   We use a dispersion representation based on unitarity and analyticity to
study the low energy $\gamma^* N\rightarrow \pi N$ process in the $S_{11}$
channel. Final state interactions among the $\pi N$ system are critical to this
analysis. The left-hand part of the partial wave amplitude is imported from
$\mathcal{O}(p^2)$ chiral perturbation theory result. On the right-hand part,
the final state interaction is calculated through Omn\`es formula in $S$ wave.
It is found that a good numerical fit can be achieved with only one subtraction
parameter, and the eletroproduction experimental data of multipole amplitudes
$E_{0+},\ S_{0+}$ in the energy region below $\Delta(1232)$ are well described
when the photon virtuality $Q^2 \leq 0.1 \mathrm{GeV}^2$.

37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph