Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Search for the reaction channel $e^+e^- \rightarrow \eta_c\eta
  \pi^+\pi^-$ at center-of-mass energies from 4.23 to 4.60 GeV   Using data collected with the BESIII detector operating at the Beijing
Electron Positron Collider, we search for the process $e^+e^-\rightarrow
\eta_c\eta \pi^+\pi^-$. The search is performed using five large data sets
recorded at center-of-mass energies of 4.23, 4.26, 4.36, 4.42, and 4.60 GeV.
The $\eta_c$ meson is reconstructed in 16 exclusive decay modes. No signal is
observed in the $\eta_c$ mass region at any center-of-mass energy. The upper
limits on the reaction cross sections are determined to be 6.2, 10.8, 27.6,
22.6 and 23.7 pb at the 90% confidence level at the center-of-mass energies
listed above.

25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph