Heavy hybrids and tetraquarks in effective field theory

Jaume Tarrús Castellà

doi:10.1051/epjconf/201920201005

Abstract

We report on an effective field theory (EFT) description of exotic quarkonia as bound states on the spectrum of hybrid and tetraquarks static energies. We provide expressions for hybrid and tetraquarks static energies in terms of Wilson loops. The former have been computed in quenched lattice calculations but the latter are yet unavailable. From the few simulations with dynamical light-quarks we argue that the overall picture from hybrid static energies does not change but additional states, such as heavy meson pairs, need to be considered for a full description. In this EFT framework for quarkonium hybrids, we report on recent results for mixing with standard quarkonium, spin-dependent contributions, and semi-inclusive decays.

Highlights

During the past 15 years, experimental observations have revealed the existence of a large number of unexpected states in the quarkonium spectrum that do not t standard quarkonium description
Exotic quarkonium can be studied in NRQCD
In the case with dynamic lightquarks new states appear, most prominently heavy-meson pairs [7] and we expect the appearance of tetraquark static energies [8, 9] as well as single-heavy-baryon pairs and quarkonium and light-quark baryon states

Summary

Introduction

During the past 15 years, experimental observations have revealed the existence of a large number of unexpected states in the quarkonium spectrum that do not t standard quarkonium description. In the case with dynamic lightquarks new states appear, most prominently heavy-meson pairs [7] and we expect the appearance of tetraquark static energies [8, 9] as well as single-heavy-baryon pairs and quarkonium and light-quark baryon states. The exotic states appear as heavy-quark antiquark bound states around the minima of these static energies This leads naturally to an energy gap between the heavy-quark antiquark binding energies. In the long-distance regime r 1/ΛQCD Eective String Theories can be used to model the long-distance part of the potentials [2, 1013] In these proceedings we briey outline the construction of EFTs for quarkonium hybrids and tetraquarks and sumarize some of the most recent results

The eective eld theory

Matching and short distance regime

Spin-dependent terms for quarkonium hybrids

Mixing with standard Quarkonia

Findings

Semi-inclusive hybrid decays