On the structures of new scalar resonances $T_{cs0}^a(2900{)}^{++}$ and $T_{cs0}^a(2900{)}^0$

Abstract

We investigate properties of the new scalar resonances $T_{cs0}^a(2900{)}^{++}$ and $T_{cs0}^a(2900{)}^0$, which were recently reported by the LHCb collaboration. These states were observed as resonant structures in $D_s^{+}{\pi }^{+}$ and $D_s^{+}{\pi }^{-}$ invariant mass distributions in $B^{+}$ meson decays. We argue that $T_{cs0}^a(2900{)}^{++}$ and $T_{cs0}^a(2900{)}^0$ may be modeled as molecules ${\mathcal{M}}^{++}=D_s^{\ast +}{\rho }^{+}$ and ${\mathcal{M}}^0=D_s^{\ast +}{\rho }^{-}$ of conventional vector mesons, respectively. The mass $m$ and current coupling $f$ of the molecule ${\mathcal{M}}^{++}$ are calculated using two-point sum rule method. The sum rule analysis is performed by taking into account vacuum condensates up to dimension $8$. The obtained result for the mass, $m=(2917\pm 135)\mathrm{MeV}$, permits us to consider the molecule ${\mathcal{M}}^{++}$ as one of possible models of the resonance $T_{cs0}^a(2900{)}^{++}$. Because the second structure $T_{cs0}^a(2900{)}^0$ is isospin partner of the doubly charged state, it should have the mass close to $m$.

Comments: 7 Pages and 3 Figures