1206.5500 (N. N. Achasov et al.)

Light scalars in semi-leptonic decays of heavy quarkonia    [PDF]

N. N. Achasov, A. V. Kiselev

We study the mechanism of production of the light scalar mesons in the $D_s^+\to\pi^+\pi^-\, e^+\nu$ decays: $D_s^+\to s\bar s\, e^+\nu\to [\sigma(600)+f_0(980)]\, e^+\nu\to\pi^+\pi^-\, e^+\nu$, and compare it with the mechanism of production of the light pseudoscalar mesons in the $D_s^+\to (\eta/\eta')\, e^+\nu$ decays: $D_s^+\to s\bar s\, e^+\nu\to (\eta/\eta')\,e^+\nu$. We show that the $s\bar s\to\sigma(600)$ transition is negligibly small in comparison with the $s\bar s\to f_0(980)$ one. As for the the $f_0(980)$ meson, the intensity of the $s\bar s\to f_0(980)$ transition makes near thirty percent from the intensity of the $s\bar s\to\eta_s$ ($\eta_s=s\bar s$) transition. So, the $D_s^+\to\pi^+\pi^-\, e^+\nu$ decay supports the previous conclusions about a dominant role of the four-quark components in the $\sigma(600)$ and $f_0(980)$ mesons.

View original: http://arxiv.org/abs/1206.5500