$D^* D \pi$ and $B^* B \pi$ couplings from Dyson-Schwinger equations framework

TL;DR

This paper uses a Dyson-Schwinger/Bethe-Salpeter equations approach to calculate strong decay couplings for D* D pi and B* B pi, providing new estimates consistent with experimental data.

Contribution

First Poincaré invariant calculation of the B* B pi coupling using Dyson-Schwinger equations framework.

Findings

Calculated g_{D^* D } and g_{B^* B } couplings with specific numerical values.

Predicted static strong couplings  g_D and g_B consistent with recent data.

First estimation of B^* B  coupling based on this method.

Abstract

Employing a unified Dyson-Schwinger/Bethe-Salpeter equations approach, we calculate the strong decay couplings $D^* D \pi$ and $B^* B \pi$ within the so-called impulse-approximation in the moving frame. The $B^* B \pi$ estimation is reported for the first time based on a Poincar\'e invariant computation of the associated Bethe-Salpeter amplitudes. Our predictions yield $g_{D^* D \pi}=16.22_{-0.01}^{+0.03}$ and $g_{B^* B \pi}=40.09_{-1.37}^{+1.51}$, along with corresponding static strong couplings of $\hat{g}_D=0.55_{-<0.01}^{+<0.01}$, $\hat{g}_B=0.50_{-0.02}^{+0.02}$, which are consistent with recent experimental and lattice data.