AdS-QCD quark-antiquark potential, meson spectrum and tetraquarks

TL;DR

This paper uses AdS/QCD and relativistic quantum mechanics to analyze meson and tetraquark spectra, accurately predicting certain exotic states and challenging some tetraquark interpretations.

Contribution

It combines AdS/QCD predictions with the Salpeter equation to determine quark and diquark masses and compute tetraquark states, providing new insights into exotic hadron candidates.

Findings

Accurately predicts masses of X(3872) and Y(3940)

Tetraquark candidates D_s(2317), D_s(2457), X(2632) are unlikely diquark-antidiquark states

Agreement with experimental data for heavy mesons is satisfactory

Abstract

AdS/QCD correspondence predicts the structure of quark-antiquark potential in the static limit. We use this piece of information together with the Salpeter equation (Schr\"odinger equation with relativistic kinematics) and a short range hyperfine splitting potential to determine quark masses and the quark potential parameters from the meson spectrum. The agreement between theory and experimental data is satisfactory provided one considers only mesons comprising at least one heavy quark. We use the same potential (in the one-gluon-exchange approximation) and these data to estimate constituent diquark masses. Using these results as an input we compute tetraquark masses using a diquark-antidiquark model. The masses of the states X(3872) or Y(3940) are predicted rather accurately. We also compute tetraquark masses with open charm and strangeness. Our result is that tetraquark candidates such as D_s(2317), D_s(2457) or X(2632) can hardly be interpreted as diquark-antidiquark states within the present approach.