Analysis of the fully-heavy pentaquark states via the QCD sum rules

Zhi-Gang Wang

doi:10.1016/j.nuclphysb.2021.115579

Abstract

In the article, we investigate the diquark-diquark-antiquark type fully-heavy pentaquark states with the spin-parity JP=12− via the QCD sum rules for the first time, and obtain the masses Mccccc¯=7.93±0.15 GeV and Mbbbbb¯=23.91±0.15 GeV. We can search for the fully-heavy pentaquark states in the J/ψΩccc and ϒΩbbb invariant mass spectrum in the future.

Highlights

IntroductionWe usually classify the hadrons into the traditional quark-antiquark type mesons, three-quark baryons, and exotic states, such as the tetraquark (molecular) states, pentaquark (molecular) states and hexaquark (molecular) states, etc
In the quark models, we usually classify the hadrons into the traditional quark-antiquark type mesons, three-quark baryons, and exotic states, such as the tetraquark states, pentaquark states and hexaquark states, etc
The exotic states provide us with a unique subject to investigate the strong interaction, which governs the dynamics of the quarks and gluons, and the confinement mechanism

Summary

Introduction

We usually classify the hadrons into the traditional quark-antiquark type mesons, three-quark baryons, and exotic states, such as the tetraquark (molecular) states, pentaquark (molecular) states and hexaquark (molecular) states, etc. In 2020, the LHCb collaboration observed a narrow structure X(6900) and a broad structure just above the J/ψJ/ψ threshold in the J/ψJ/ψ invariant mass spectrum [5], such structures are the first fully-heavy exotic multiquark candidates claimed experimentally up to now. It is a very important step in investigations of the heavy hadrons, and provides very important experimental constraints on the theoretical models. P-wave and D-wave diquarks as the basic building blocks to investigate the doubly-heavy baryon states, tetraquark states and pentaquark states, we expect to obtain larger hadron masses considering the additional contributions from the P-waves and D-wave.

QCD sum rules for the fully-heavy pentaquark states

Numerical results and discussions

Central value ccccc

Conclusion