Open-charm tetraquark \(X_c\) and open-bottom tetraquark \(X_b\)

Abstract

Motivated by the LHCb observation of exotic states \[X_{0,1}(2900)\] with four open quark flavors in the \[D^- K^+\] invariant mass distribution in the decay channel \[B^\pm \rightarrow D^+ D^- K^\pm \] , we study the spectrum and decay properties of the open charm tetraquarks. Using the two-body chromomagnetic interactions, we find that the two newly observed states can be interpreted as a radial excited tetraquark with \[J^P=0^+\] and an orbitally excited tetraquark with \[J^P=1^-\] , respectively. We then explore the mass and decays of the other flavor-open tetraquarks made of \[su {\bar{d}} {\bar{c}}\] and \[ d s {\bar{u}} {\bar{c}}\] , which are in the \[{\bar{6}}\] or 15 representation of the flavor SU(3) group. We point that these two states can be found through the decays: \[X^{(\prime )}_{d s \bar{u}\bar{c}}\rightarrow (D^- K^-, D_s^- \pi ^-) \] , and \[X^{(\prime )}_{s u \bar{d}\bar{c}}\rightarrow D_s^-\pi ^+ \] . We also apply our analysis to open bottom tetraquark \[X_b\] and predict their masses. The open-flavored \[X_b\] can be discovered through the following decays: \[X_{ud{\bar{s}}\bar{b}}\rightarrow B^0K^+\] , \[X^{(\prime )}_{d s \bar{u}\bar{b}}\rightarrow (B^0 K^-, B_s^0 \pi ^-) \] , and \[X^{(\prime )}_{s u \bar{d}\bar{b}}\rightarrow B_s^0\pi ^+ \] .