Dynamics of strong and radiative decays of Ds mesons

Abstract

The positive parity scalar D${}_{s0}^{\ast }$(2317) and axial-vector D${}_{s1}^{\ast }$(2460) charmed strange mesons are generated by coupled-channel dynamics through the s-wave scattering of Goldstone bosons off the pseudoscalar and vector D(D${}_s$)-meson ground states. The attraction leading to the specific masses of these states reflects the chiral symmetry breaking scale which characterizes the Weinberg-Tomozawa interaction in the chiral Lagrangian. Chiral corrections to order Q${}_{\chi }^2$ are calculated and found to be small. The D${}_{s0}^{\ast }$(2317) and D${}_{s1}^{\ast }$(2460) mesons decay either strongly into the isospin-violating ${\pi }^0$D${}_s$ and ${\pi }^0$D${}_s^{\ast }$ channels or electromagnetically. We show that the ${\pi }^0$-$\eta$ and (K${}^0$D${}^{+}$-K${}^{+}$D${}^0$) mixings act constructively to generate strong widths of the order of 140 keV. The one-loop contribution to the radiative decay amplitudes of scalar and axial-vector states is calculated using the electromagnetic Lagrangian to chiral order Q${}_{\chi }^2$. We show the importance of taking into account processes involving light vector mesons explicitly in the dynamics of electromagnetic decays to obtain a satisfactory description of the available data.

Comments: Contribution to the Meson 2008 Conference, June 6-10, Cracow, Poland