Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mass Spectra and Decay of Mesons under Strong External Magnetic Field   We study the mass spectra and decay process of $\sigma$ and $\pi_0$ mesons
under strong external magnetic field. For this purpose, we deduce the
thermodynamic potential in a two-flavor, hot and magnetized Nambu-Jona-Lasinio
model. We calculate the energy gap equation through the random phase
approximation(RPA). Then we use Ritus method to calculate the decay triangle
diagram and self-energy in the presence of a constant magnetic field B. Our
results indicate that the magnetic field has little influence on the mass of
$\pi_0$ at low temperatures. While for quarks and $\sigma$ mesons, their mass
changes obviously, which reflects the influence of magnetic catalysis(MC). The
presence of magnetic field accelerates the decay of the meson while the
presence of chemical potential will decrease the decay process.

19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph