Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On a possible origin of a resonance-like structure in the two-photon
  invariant mass spectrum of the reaction pp->ppgg   We show that the resonance-like structure found by the \emph{CELSIUS-WASA
Collaboration} in the two-photon invariant mass spectrum of the reaction $pp
\to pp \gamma \gamma$ is rather a signature of the $NN$-decoupled dibaryon
resonance $d^\star_1$(1956) that is produced in the radiative process $pp \to
\gamma d^\star_1$ and then undergoes radiative decay into two protons
$d^\star_1 \to pp \gamma$. It is found that a contribution of the dibaryon
mechanism $pp \to \gamma d^\star_1 \to pp \gamma \gamma$ of the reaction $pp
\to pp \gamma \gamma$ to the invariant mass spectrum of its photon pairs can
reasonably well reproduce the experimentally observed spectrum in the vicinity
of the resonance-like structure.

3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th