Effect of relativistic kinematics on the stability of multiquarks

TL;DR

This paper investigates how relativistic kinetic energy corrections influence the stability of multiquark states, revealing increased stability for certain tetraquarks with double heavy flavors, but not for all-heavy tetraquarks.

Contribution

It provides a comparative analysis of non-relativistic and relativistic kinetic energy effects on multiquark stability, highlighting the impact on specific tetraquark configurations.

Findings

Relativistic corrections lower multiquark binding energies.

Double heavy flavor tetraquarks become more stable relativistically.

All-heavy tetraquarks remain unstable under relativistic kinetic energy.

Abstract

We discuss whether the bound nature of multiquark states in quark models could benefit from relativistic effects on the kinetic energy operator. For mesons and baryons, relativistic corrections to the kinetic energy lead to lower energies, and thus call for a retuning of the parameters of the model. For multiquark states, as well as their respective thresholds, a comparison is made of the results obtained with non-relativistic and relativistic kinetic energy. It is found that the binding energy is lower in the relativistic case. In particular, $QQ\bar q\bar q$ tetraquarks with double heavy flavor become stable for a larger ratio of the heavy to light quark masses; and the all-heavy tetraquarks $QQ\bar Q\bar Q$ that are not stable in standard non-relativistic quark models remain unstable when a relativistic form of kinetic energy is adopted