Displaced Bc\u2212 mesons as an inclusive signature of weakly decaying double beauty hadrons

T Gershon,A Poluektov

doi:10.1007/jhep01(2019)019

Abstract

The recent discovery, by the LHCb collaboration, of the Ξcc+ + doubly charmed baryon, has renewed interest in the spectroscopy of doubly heavy hadrons. Experimentally, however, searches for such states appear highly challenging. The reconstructed final states tend to involve multiple heavy flavoured (beauty or charm) hadrons, so the yield for any exclusive decay mode will be suppressed to unobservably low levels by the product of several branching fractions, each of which is typically 10−3–10−2. Noting that decays of double beauty hadrons are the only possible source of Bc− mesons that are displaced from the primary vertices of proton-proton collisions at the LHC, a more promising inclusive search strategy is proposed.

Highlights

The possible existence of doubly heavy baryons, i.e. bound states that contain two or more beauty or charm quarks, has been predicted since the discoveries of those quarks, not long after the postulation of the quark model
The reconstructed final states tend to involve multiple heavy flavoured hadrons, so the yield for any exclusive decay mode will be suppressed to unobservably low levels by the product of several branching fractions, each of which is typically 10−3–10−2
Noting that decays of double beauty hadrons are the only possible source of Bc− mesons that are displaced from the primary vertices of proton-proton collisions at the LHC, a more promising inclusive search strategy is proposed

Summary

Introduction

The possible existence of doubly heavy baryons, i.e. bound states that contain two or more beauty or charm quarks, has been predicted since the discoveries of those quarks, not long after the postulation of the quark model. The reconstructed final states tend to involve multiple heavy flavoured (beauty or charm) hadrons, so the yield for any exclusive decay mode will be suppressed to unobservably low levels by the product of several branching fractions, each of which is typically 10−3–10−2.

Results

Conclusion