Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of the beam-helicity asymmetry in photoproduction of
  $\pi^{0}\eta$ pairs on carbon, aluminum, and lead   The beam-helicity asymmetry was measured, for the first time, in
photoproduction of $\pi^{0}\eta$ pairs on carbon, aluminum, and lead, with the
A2 experimental setup at MAMI. The results are compared to an earlier
measurement on a free proton and to the corresponding theoretical calculations.
The Mainz model is used to predict the beam-helicity asymmetry for the nuclear
targets. The present results indicate that the photoproduction mechanism for
$\pi^{0}\eta$ pairs on nuclei is similar to photoproduction on a free nucleon.
This process is dominated by the $D_{33}$ partial wave with the
$\eta\Delta(1232)$ intermediate state.

27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph