Pion couplings to the scalar B meson

TL;DR

This study uses lattice QCD with HQET to estimate hadronic couplings related to non-leptonic B meson decays, providing insights into multihadronic state contributions in lattice calculations.

Contribution

It introduces a method to disentangle B meson states from multihadronic states using GEVP in lattice QCD with HQET, focusing on S-wave states.

Findings

Successful estimation of $g_{B^*_0 B \pi}$ and $g_{B_1^* B_0^* \pi}$ couplings.

Insights into handling multihadronic states in lattice correlation functions.

Application of GEVP to separate states in lattice QCD.

Abstract

We present two-flavor lattice QCD estimates of the hadronic couplings $g_{B^*_0 B \pi}$ and $g_{B_1^* B_0^* \pi}$ that parametrise the non leptonic decays $B^*_0 \to B \pi$ and $B^*_1 \to B_0^* \pi$. We use CLS two-flavour gauge ensembles. Our framework is the Heavy Quark Effective Theory (HQET) in the static limit and solving a Generalized Eigenvalue Problem (GEVP) reveals crucial to disentangle the $B^*_0$($B^*_1$) state from the $B \pi$($B^*\pi$) state. This work brings us some experience on how to treat the possible contribution from multihadronic states to correlation functions calculated on the lattice, especially when $S$-wave states are involved.