Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Differential cross section and analyzing power of the ${\vec
  p}p{\to}pp{\pi}^0$ reaction at a beam energy of 390 MeV   The differential cross section and analyzing power $A_y$ of the ${\vec
p}p{\to}pp{\pi}^0$ reaction have been measured at RCNP in coplanar geometry at
a beam energy of 390 MeV and the dependence on both the pion emission angle and
the relative momentum of the final protons have been extracted. The angular
variation of Ay for the large values of the relative momentum studied here
shows that this is primarily an effect of the interference of pion s- and
p-waves and this interference can also explain the momentum dependence. Within
the framework of a very simple model, these results would suggest that the
pion-production operator has a significant long-range component.

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The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin