Triply-charmed dibaryon states or two-baryon scattering states from QCD sum rules

Zhi-Gang Wang

doi:10.1103/physrevd.102.034008

Abstract

In this article, we construct the color-singlet-color-singlet type currents to study the scalar and axialvector $\Xi_{cc}\Sigma_c$ dibaryon states with QCD sum rules in details by taking into account both the dibaryon states and two-baryon scattering sates at the hadron side, and examine the existence of the $\Xi_{cc}\Sigma_c$ dibaryon states. Our calculations indicate that the two-baryon scattering states cannot saturate the QCD sum rules, it is necessary to introduce the dibaryon states, the color-singlet-color-singlet type currents couple potentially to the molecular states, not to the two-particle scattering states, the molecular states begin to receive contributions at the order $\mathcal{O}(\alpha_s^0)$, not at the order $\mathcal{O}(\alpha_s^2)$.

Highlights

A dibaryon state denotes an object with baryon number 2, the oldest known dibaryon state is the deuteron, which is a very loosely bound state of two baryons, a proton and a neutron, and is made of six light valence quarks
A different voice arises, Lucha, Melikhov, and Sazdjian assert that the QCD sum rules are misused to study the tetraquark or molecule masses, all the four-quark currents can be rearranged into the color-singlet-color-singlet type currents, the contributions at the order OðαksÞ with k ≤ 1 in the operator product expansion, which are factorizable in the color space, are exactly canceled out by the two-meson scattering states at the hadron side, the tetraquark molecular states begin to receive contributions at the order Oðα2sÞ [24,25]
We study the scalar and axialvector ΞccΣc dibaryon states with QCD sum rules in details

Summary

INTRODUCTION

A dibaryon state denotes an object with baryon number 2, the oldest known dibaryon state is the deuteron, which is a very loosely bound state of two baryons, a proton and a neutron, and is made of six light valence quarks. It is interesting to study the ΣcΞcc dibaryon states with the QCD sum rules, as we have experimental input to assess the bound energies. A different voice arises, Lucha, Melikhov, and Sazdjian assert that the QCD sum rules are misused to study the tetraquark or molecule masses, all the four-quark currents can be rearranged into the color-singlet-color-singlet type currents, the contributions at the order OðαksÞ with k ≤ 1 in the operator product expansion, which are factorizable in the color space, are exactly canceled out by the two-meson scattering states at the hadron side, the tetraquark molecular states begin to receive contributions at the order Oðα2sÞ [24,25]. We will examine the applicability of the QCD sum rules to study the two-baryon type molecular states.

QCD SUM RULES FOR THE DIBARYON STATES

NUMERICAL RESULTS AND DISCUSSIONS

CONCLUSION