$B_{c}^{\pm}$ decays into tetraquarks

The recent observation by the D0 collaboration of a narrow structure X(5568) consisting of four different quark flavors bdus, has not been confirmed by LHCb. More data and dedicated analyses are needed to cover a larger mass range. In the tightly bound diquark model, we estimate the lightest bdus, 0$^+$ tetraquark at a mass of about 5770 MeV, approximately 200 MeV above the reported X(5568), and just 7 MeV below the $B\bar{K}$ threshold. The charged tetraquark is accompanied by I = 1 and I = 0 neutral partners almost degenerate in mass. A bdus, S-wave, 1$^+$ quartet at 5820 MeV is implied as well. In the charm sector, cdus, 0$^+$ and 1$^+$ tetraquarks are predicted at 2365 MeV and 2501 MeV, about 40-50 MeV heavier than D$_{s0}$(2317) and D$_{s1}$(2460). bdus tetraquarks can be searched in the hadronic debris of a jet initiated by a b. However, some of them may also be produced in B$_c$ decays. The proposed discovery modes of S-wave tetraquarks are $B_{c} \to X_{b0} + \pi$ with the subsequent decays $X_{b0} \to B_{s} + \pi$, giving rise to final states such as $B_{s} \pi^{+} \pi^0$. We also emphasize the importance of $B_c$ decays as a source of bound hidden charm tetraquarks, such as $B_{c} \to X(3872) + \pi$