Exotic open-flavor \(bc\bar{q}\bar{q}\), \(bc\bar{s}\bar{s}\) and \(qc\bar{q}\bar{b}\), \(sc\bar{s}\bar{b}\) tetraquark states

Abstract

We study the exotic \(bc\bar{q}\bar{q}\), \(bc\bar{s}\bar{s}\) and \(qc\bar{q}\bar{b}\), \(sc\bar{s}\bar{b}\) systems by constructing the corresponding tetraquark currents with \(J^P=0^+\) and \(1^+\). After investigating the two-point correlation functions and the spectral densities, we perform QCD sum rule analysis and extract the masses of these open-flavor tetraquark states. Our results indicate that the masses of both the scalar and axial vector tetraquark states are about \(7.1-7.2\) GeV for the \(bc\bar{q}\bar{q}\) system and \(7.2-7.3\) GeV for the \(bc\bar{s}\bar{s}\) system. For the \(qc\bar{q}\bar{b}\) tetraquark states with \(J^P=0^+\) and \(1^+\), their masses are extracted to be around \(7.1\) GeV. The masses for the scalar and axial vector \(sc\bar{s}\bar{b}\) states are \(7.1\) GeV and \(6.9-7.1\) GeV, respectively. The tetraquark states \(qc\bar{q}\bar{b}\) and \(sc\bar{s}\bar{b}\) lie below the thresholds of \(D^{(\ast)}B^{(\ast)}\) and \(D_s^{(\ast)}B_s^{(\ast)}\) respectively, but they can decay into \(B_c\) plus a light meson. However, the tetraquark states \(bc\bar{q}\bar{q}\) and \(bc\bar{s}\bar{s}\) lie below the \(D^{(\ast)}\bar B^{(\ast)}\) and \(D_s^{(\ast)}\bar B_s^{(\ast)}\) thresholds, suggesting dominantly weak decay mechanisms.