What are effective $a_1$ and $a_2$ in two-body hadronic decays of D and B mesons?

A. N. Kamal, A. B. Santra, F. Ghoddoussi

Through a specific example of two-body color-favored charm decay, $D_s^{+}\to \varphi {\pi }^{+}$, we illustrate how an effective and complex (unitarized) $a_1$, denoted by $a_1^{U,eff}$…