Strong decays of double-charmed pseudoscalar and scalar $cc\overline{u}\overline{d}$ tetraquarks

Abstract

The strong decays of the pseudoscalar and scalar double-charmed tetraquarks $T_{cc;\overline{u}\overline{d}}^{+}$ and ${\tilde{T}}_{cc;\overline{u}\overline{d}}^{+}$ are investigated in the framework of the QCD sum rule method. The mass and coupling of these exotic four-quark mesons are calculated in the framework of the QCD two-point sum rule approach by taking into account vacuum condensates of the quark, gluon, and mixed local operators up to dimension 10. Our results for masses $m_T=(4130\pm 170)\mathrm{MeV}$ and $m_{\tilde{T}}=(3845\pm 175)\mathrm{MeV}$ demonstrate that these tetraquarks are strong-interaction unstable resonances and decay to conventional mesons through the channels $T_{cc;\overline{u}\overline{d}}^{+}\to D^{+}{D}^{\ast }(2007{)}^0,D^0{D}^{\ast }(2010{)}^{+}$ and ${\tilde{T}}_{cc;\overline{u}\overline{d}}^{+}\to D^{+}{D}^0$. Key quantities necessary to compute the partial width of these decay modes, i.e., the strong couplings of two $D$ mesons and a corresponding tetraquark $g_i,i=1,2$, and $G$ are extracted from the QCD three-point sum rules. The full width ${\Gamma }_T=(129.9\pm 23.5)\mathrm{MeV}$ demonstrates that the tetraquark $T_{cc;\overline{u}\overline{d}}^{+}$ is a broad resonance, whereas the scalar exotic meson with ${\Gamma }_{\tilde{T}}=(12.4\pm 3.1)\mathrm{MeV}$ can be classified as a relatively narrow state.

Comments: 9 Pages, 4 Figures and 1 Table. A typo was corrected