$B_s\pi^+$ scattering and search for X(5568) with lattice QCD

TL;DR

This study uses lattice QCD to investigate the existence of the exotic X(5568) resonance in $B_s o ext{pi}^+$ scattering, finding no evidence for it and supporting recent LHCb results.

Contribution

First lattice QCD analysis searching for X(5568) in $B_s o ext{pi}^+$ scattering, providing evidence against its existence as a $J^P=0^+$ state.

Findings

No candidate for X(5568) found in lattice simulation.

Scattering length consistent with zero.

Supports recent LHCb null result.

Abstract

We investigate $B_s\pi^+$ scattering in s-wave using lattice QCD in order to search for an exotic resonance X(5568) with flavor $\bar b s \bar d u$; such a state was recently reported by D0 but was not seen by LHCb. If X(5568) with $J^P=0^+$ exists, it can strongly decay only to $B_s\pi^+$ and lies significantly below all other thresholds, which makes a lattice search for X(5568) cleaner and simpler than for other exotic candidates. Both an elastic resonance in $B_s\pi^+$ as well as a deeply bound $B^+\bar K^0$ would lead to distinct signatures in the energies of lattice eigenstates, which are not seen in our simulation. We therefore do not find a candidate for X(5568) with $J^P=0^+$ in agreement with the recent LHCb result. The extracted $B_s\pi^+$ scattering length is compatible with zero within the error.