Dynamics of strong and radiative decays of Ds-mesons in the hadrogenesis conjecture

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 specific masses of these states are obtained as a consequence of the attraction arising from 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 and emphasize the sensitivity of this value to the $KD$ component of the states. 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. The radiative width are sensitive to both $\eta D_s$ and $KD$ components, hence providing information complementary to the strong widths on the positive parity $D_s$-meson structure.

Comments: 4 pages, Invited Contribution to QNP09, Beijing, September 21-26, 2009