Electromagnetic form factors of light vector mesons

Abstract

The electromagnetic form factors GE(q²), GM(q²), and GQ(q²), charge radii, magnetic and quadrupole moments, and decay widths of the light vector mesons ρ⁺,K*⁺, and K*0 are calculated in a Lorentz-covariant, Dyson-Schwinger-equation-based model using algebraic quark propagators that incorporate confinement, asymptotic freedom, and dynamical chiral symmetry breaking, and vector-meson Bethe-Salpeter amplitudes closely related to the pseudoscalar amplitudes obtained from phenomenological studies of π and K mesons. Calculated static properties of vector mesons include the charge radii and magnetic moments 〈rρ+²〉1/2=0.61 fm, 〈rK*⁺²〉1/2=0.54 fm, and 〈rK*0²〉=-0.048 fm² and μρ+=2.69, μK*⁺=².37, and μK*0=-0.40. The calculated static limits of the ρ-meson form factors are similar to those obtained from light-front quantum mechanical calculations, but begin to differ above q²=1 GeV2 due to the dynamical evolution of the quark propagators in our approach.