rho meson form factors in a confining Nambu-Jona-Lasinio model

Elastic electromagnetic form factors for the ρ⁺ meson are calculated in a Nambu–Jona-Lasinio model which incorporates quark confinement through the use of the proper-time regularization scheme. A comparison is made with recent lattice QCD results and previous quark model calculations for static quantities and the Sachs form factors. The results are qualitatively in good agreement with the lattice QCD calculations, with the exception of the quadrupole moment and corresponding form factor, which may be related to a lack of spherical symmetry on the lattice.Manuel E. Carrillo-Serrano, Wolfgang Bentz, Ian C. Cloët, and Anthony W. Thoma