Electromagnetic structure of charged and neutral strange vector mesons

Abstract

We investigate the electromagnetic form factors (EMFFs) of the charged $K^{\ast +}(892)$ ($u\bar{s}$) and neutral $K^0(896)$ ($d\bar{s}$) strange vector mesons within the covariant Nambu--Jona-Lasinio (NJL) model, employing the Schwinger proper-time regularization scheme to regularize ultraviolet divergences while incorporating the QCD aspect of quark confinement. To this end, we evaluate the charge (electric) $G_C(Q^2)$, magnetic $G_M(Q^2)$, and quadrupole $G_Q(Q^2)$ form factors, as well as the charge radii, of the charged $K^{+}(892)$ and neutral $K^0(896)$ strange vector mesons. We find the charge radii to be $⟨r^2{⟩}_{K^{+}}=0.45{\mathrm{fm}}^2$ and $⟨r^2{⟩}_{K^0}=-0.04{\mathrm{fm}}^2$, respectively, while the corresponding magnetic moments are $\hat{I}{¼}_{K^{+}}=2.67,\hat{I}{¼}_N$ and $\hat{I}{¼}_{K^{\ast 0}}=0.032,\hat{I}{¼}_N$. These results are consistent with other theoretical calculations and lattice QCD simulations.

10 pages, 8 figures, 1 table