Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Partial wave decomposition of pion and photoproduction amplitudes   Partial wave amplitudes for production and decay of baryon resonances are
constructed in the framework of the operator expansion method. The approach is
fully relativistically invariant and allow us to perform combined analyses of
different reactions imposing directly analyticity and unitarity constraints.
All formulas are given explicitly in the form used by the Crystal Barrel
collaboration in the (partly forthcoming) analyses of the electro-, photo- and
pion induced meson production data.

34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn