Analysis of the doubly heavy baryon states and pentaquark states with QCD sum rules

Zhi-Gang Wang

doi:10.1140/epjc/s10052-018-6300-4

Abstract

In this article, we study the doubly heavy baryon states and pentaquark states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 7 and 13 respectively in a consistent way. In calculations, we separate the contributions of the negative parity and positive parity hadron states unambiguously, and study the masses and pole residues of the doubly heavy baryon states and pentaquark states in details. The present predictions can be confronted to the experimental data in the future.

Highlights

In 2017, the LHCb collaboration observed the doubly charmed baryon state ++ cc in the + c K −π+π+mass spectrum, and obtained the mass M ++ = 3621.40 ± 0.72 ± cc0.27 ± 0.14 MeV [1]
We carry out the operator product expansion up to the vacuum condensates of dimension 4 for the positive parity doubly heavy baryon states [18,19], another detailed studied including the contributions of the higher dimensional vacuum condensates are still needed
In Ref. [48], we study the diquark–diquark–antiquark type charmed pentaquark states with 3± 2 with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 13 in a consistent way to explore the possible assignments of the new excited c states as the pentaquark states

Summary

Introduction

++ cc provides the crucial experimental input on the strong correlation between the two charm quarks, which may shed light on the spectroscopy of the doubly charmed baryon states, tetraquark states and pentaquark states. We carry out the operator product expansion up to the vacuum condensates of dimension 4 for the positive parity doubly heavy baryon states [18,19], another detailed studied including the contributions of the higher dimensional vacuum condensates are still needed. Sum rules in a systematic way by taking into account the vacuum condensates up to dimension 10 in the operator product expansion and separating the contributions of the positive parity and negative parity pentaquark states explicitly. Mc to determine the ideal energy scales of the QCD spectral densities

QCD sum rules for the doubly heavy baryon states and pentaquark states

Numerical results and discussions

Conclusion