Modeling the resonance $T_{cs0}^{a}(2900)^{++}$ as a hadronic molecule $D^{\ast +}K^{\ast +}$

TL;DR

This paper models the doubly charged scalar resonance $T_{cs0}^{a}(2900)^{++}$ as a hadronic molecule composed of vector mesons, calculating its properties using QCD sum rules and decay widths to support its identification as this resonance.

Contribution

It introduces a hadronic molecule model for $T_{cs0}^{a}(2900)^{++}$ and computes its mass, width, and decay couplings using advanced QCD techniques, providing a new interpretation of this resonance.

Findings

Predicted mass of the molecule: 2924 ± 107 MeV

Predicted width of the molecule: 123 ± 25 MeV

Supports the resonance as a hadronic molecule candidate

Abstract

The doubly charged scalar resonance $T_{cs0}^{a}(2900)^{++}$ is studied in the context of the hadronic molecule model. We consider $ T_{cs0}^{a}(2900)^{++}$ as a molecule $M=D^{\ast +}K^{\ast +}$ composed of vector mesons, and calculate its mass, current coupling and full width. The spectroscopic parameters of $M$, i.e., its mass and current coupling, are found by means of the QCD two-point sum rule method by taking into account vacuum expectation values of quark, gluon and mixed operators up to dimension $10$. The width of the molecule $M$ is evaluated through the calculations of the partial widths of the decay channels $M \to D_{s}^{+}\pi^{+}$, $M \to D_{s}^{\ast +}\rho^{+}$, and $M \to D^{\ast +}K^{\ast +}$. Partial widths of these processes are determined by strong couplings $g_1$, $g_2$, and $g_3$ of particles at vertices $ MD_{s}^{+}\pi^{+} $, $MD_{s}^{\ast +}\rho^{+}$, and $M D^{\ast +}K^{\ast +}$ , respectively. We calculate the couplings $g_i$ by employing the QCD light-cone sum rule approach and technical tools of the soft-meson approximation. Predictions obtained for the mass $m=(2924 \pm 107)~\mathrm{ MeV}$ and width $\Gamma=(123 \pm 25)~\mathrm{MeV}$ of the hadronic molecule $ M$ allow us to consider it as a possible candidate of the resonance $ T_{cs0}^{a}(2900)^{++}$.