Semileptonic decays $D\to \eta \pi e^{+}{\nu }_e$ in the $a_0(980)$ region

Abstract

The mechanism of the four-quark production of the light scalar isovector four-quark state $a_0(980)$ in the $D\to \eta \pi e^{+}{\nu }_e$ decays is discussed. It is shown that the characteristic features of the shape of the $\eta \pi$ mass spectra expected in our scheme can serve as the indicator of the production mechanism and internal structure of the $a_0(980)$ resonance.

Comments: 11 pages, 11 figures, v2: clarifications added, version published in Phys. Rev. D