XYZ - SU3 Breakings from Laplace Sum Rule at Higher Orders: Summary

TL;DR

This paper uses advanced QCD Laplace Sum Rules at higher orders to analyze XYZ meson states, finding small SU3 breaking effects on masses but larger effects on couplings, and discussing the nature of these states.

Contribution

It provides a detailed higher-order QCD sum rule analysis of XYZ states, including SU3 breaking corrections and non-perturbative effects, offering insights into their molecular or four-quark nature.

Findings

SU3 breaking effects on masses are less than 10% for charm and 3% for bottom channels.

Couplings decrease faster with increasing bottom quark mass, following 1/m_b^{3/2}.

The approach cannot definitively distinguish molecule states from four-quark states within errors.

Abstract

This talk reviews and summarizes some of our results in [1] on XYZ- SU3 Breakings obtained from QCD Laplace Sum Rules (LSR) at next-to-next-leading order (N2LO) of perturbative (PT) theory and including next-to-leading order (NLO) SU3 breaking corrections and leading order (LO) contributions of dimensions d< (6 - 8) non-perturbative condensates. We conclude that the observed X states are good candidates for being 1^++ and 0^++ molecules states. We find that the SU3 breakings are relatively small for the masses (< 10 (resp. 3) %) for the charm (resp. bottom) channels while they are large (< 20 %) for the couplings. Like in the chiral limit case, the couplings decrease faster: 1/m_b^3/2 than 1/m_b^1/2 of HQET. Our approach cannot clearly separate ( within the errors ) some molecule states from the four-quark ones with the same quantum numbers.