0000000000326116
AUTHOR
N. N. Scoccola
Neutral and charged pion properties under strong magnetic fields in the NJL model
In the framework of the Nambu-Jona-Lasino (NJL) model, we study the effect of an intense external uniform magnetic field on neutral and charged pion masses and decay form factors. In particular, the treatment of charged pions is carried out on the basis of the Ritus eigenfunction approach to magnetized relativistic systems. Our analysis shows that in the presence of the magnetic field three and four nonvanishing pion-to-vacuum hadronic form factors can be obtained for the case of the neutral and charged pions, respectively. As expected, it is seen that for nonzero magnetic field the π⁰ meson can still be treated as a pseudo Nambu-Goldstone boson, and consequently the corresponding form fact…
Magnetic field driven enhancement of the weak decay width of charged pions
We study the effect of a uniform magnetic field B→ on the decays π⁻ → l⁻ ν⁻l, where l⁻ = e⁻, μ⁻, carrying out a general analysis that includes four π⁻ decay constants. Taking the values of these constants from a chiral effective Nambu-Jona-Lasinio (NJL) model, it is seen that the total decay rate gets strongly increased with respect to the B = 0 case, with an enhancement factor ranging from ∼ 10 for eB = 0.1 GeV² up to ∼ 10³ for eB = 1 GeV². The ratio between electronic and muonic decays gets also enhanced, reaching a value of about 1 : 2 for eB = 1 GeV². In addition, we find that for large B the angular distribution of outgoing antineutrinos shows a significant suppression in the direction…