𝐷*⁢𝐷⁢𝜋 and 𝐵*⁢𝐵⁢𝜋 couplings from Dyson-Schwinger equations framework

Abstract

Employing a unified Dyson-Schwinger/Bethe-Salpeter equations approach, we calculate the strong decay couplings 𝐷*⁢𝐷⁢𝜋 and 𝐵*⁢𝐵⁢𝜋 within the so-called impulse-approximation in the moving frame. The 𝐵*⁢𝐵⁢𝜋 estimation is reported for the first time based on a Poincaré invariant computation of the associated Bethe-Salpeter amplitudes. Our predictions yield 𝑔𝐷*⁢𝐷⁢𝜋 =16.2⁢2+0.03−0.01 and 𝑔𝐵*⁢𝐵⁢𝜋 =40.0⁢9+1.51−1.37, along with corresponding static strong couplings of ^𝑔𝐷 =0.5⁢5+<0.01−<0.01, ^𝑔𝐵 =0.5⁢0+0.02−0.02, which are consistent with recent experimental and lattice data.