Heavy-Light Exotics from QCD Laplace Sum Rules at N2LO in the chiral limit

TL;DR

This paper uses advanced QCD Laplace Sum Rules at N2LO to analyze exotic heavy-light meson spectra, suggesting certain observed states are likely molecules or four-quark states, and refuting the existence of the X(5568).

Contribution

It provides the first N2LO QCD sum rule analysis of $XYZ$-like spectra including non-perturbative condensates, offering new insights into exotic heavy-light mesons.

Findings

Observed $XZ$ states are good candidates for $1^{+}$ and $0^+$ molecules or four-quark states.

Predictions for $1^-$ and $0^-$ states are about 1.5 GeV above experimental candidates.

The study finds weak coupling of exotic molecules to interpolating currents, decreasing faster with $1/m_b$.

Abstract

These talks review and summarize our results in [1,2] on $XYZ$-like spectra obtained from QCD Laplace Sum Rules in the chiral limit at next-to-next-leading order (N2LO) of perturbation theory (PT) and including leading order (LO) contributions of dimensions $d\leq 6-8$ non-perturbative condensates. We conclude that the observed $XZ$ states are good candidates for $1^{+}$ and $0^+$ molecules or / and four-quark states while the predictions for $1^-$ and $0^-$ states are about 1.5 GeV above the $Y_{c,b}$ experimental candidates and hadronic thresholds. We (numerically) find that these exotic molecules couple weakly to the corresponding interpolating currents than ordinary $D,B$ heavy-light mesons while we observe that these couplings decrease faster [$1/m_b^{3/2}$ (resp. $1/m_b$) for the $1^+,0^+$ (resp. $1^-,0^-)$ states] than $1/m_b^{1/2}$. Our results do not also confirm the existence of the $X(5568)$ state in agreement with LHCb findings.