Generating a resonance-like structure in the reaction B_crightarrow B_s pi pi

Xiao-Hai Liu,Ulf-G Meißner

doi:10.1140/epjc/s10052-017-5402-8

Abstract

We investigate the process B_c^+rightarrow B_s^0pi ^+pi ^0 via Bbar{K}^* rescattering. The kinematic conditions for triangle singularities are perfectly satisfied in the rescattering diagrams. A resonance-like structure around the Bbar{K} threshold, which we denote X(5777), is predicted to be present in the invariant mass distribution of B_s^0 pi ^+. Because the relative weak Bbar{K}(I=1) interaction does not support the existence of a dynamically generated hadronic molecule, X(5777) can be identified as a pure kinematical effect due to the triangle singularity. Its observation may help to establish a non-resonance interpretation for some XYZ particles.

Highlights

Background analysisThe rescattering processes in Fig. 1 is just one of the contributions to three-body decay Bc+ → Bs0π +π 0
This implies that the rescattering diagram can be interpreted as a classical process in spacetime in the presence of triangle singularity (TS), and the TS will be located on the physical boundary of the rescattering amplitude [12]
In Eq (2), we introduce a monopole form factor F(q32) = (m2K − 2)/(q32 − 2) to account for the offshell effect and kill the ultraviolet divergence that appears in the loop integral

Summary

Introduction

– bound systems of two hadrons analogous to conventional nuclei. The deuteron, which is composed of a proton and a neutron, is a typical example of a hadronic molecule. The TS peak usually appears in the vicinity of a threshold of scattering particles From this point of view, the TS mechanism is similar to the hadronic molecule interpretation, and it implies that the genuine dynamic pole may mix with the TS peak. This implies that the rescattering diagram can be interpreted as a classical process in spacetime in the presence of TS, and the TS will be located on the physical boundary of the rescattering amplitude [12]. These are the kinematical regions where the TS can be present in the physical rescat-

Rescattering amplitude

B Kchannel a

Background analysis

Findings

Summary