Axial-vector and pseudoscalar tetraquarks [ud][{overline{c}}{overline{s}}

Abstract

Spectroscopic parameters and widths of the fully open-flavor axial-vector and pseudoscalar tetraquarks X_{textrm{AV}} and X_{textrm{PS}} with content [ud][{overline{c}}{overline{s}}] are calculated by means of the QCD sum rule methods. Masses and current couplings of X_{textrm{AV}} and X_{textrm{PS}} are found using two-point sum rule computations performed by taking into account various vacuum condensates up to dimension 10. The full width of the axial-vector state X_{textrm{AV}} is evaluated by including into analysis S-wave decay modes X_{textrm{AV}}rightarrow D^{*}(2010)^{-}K^{+}, {overline{D}}^{*}(2007)^{0}K^{0}, D^{-}K^{*}(892)^{+}, and {overline{D}}^{0}K^{*}(892)^{0}. In the case of X_{textrm{PS}}, we consider S-wave decay X_{textrm{PS}}rightarrow {overline{D}} _{0}^{*}(2300)^{0}K^{0}, and P-wave processes X_{textrm{PS}}rightarrow D^{-}K^{*}(892)^{+} and X_{textrm{PS}}rightarrow {overline{D}} ^{0}K^{*}(892)^{0}. To determine partial widths of these decay modes, we employ the QCD light-cone sum rule method and soft-meson approximation, which are necessary to estimate strong couplings at tetraquark–meson–meson vertices X_{textrm{AV}}D^{-}D^{*}(2010)^{-}K^{+} , etc. Our predictions for the mass m_{textrm{AV}}=(2800 pm 75)~text {MeV} and width Gamma _{textrm{AV}}=(58 pm 10)~text {MeV} of the tetraquark X_{ textrm{AV}}, as well as results m_{textrm{PS}}=(3000 pm 60)~text {MeV} and Gamma _{textrm{PS}}=(65 pm 12)~text {MeV} for the same parameters of X_{textrm{PS}} may be useful in future experimental studies of multiquark hadrons.