Search for the X(5568) state decaying into ${\mathrm{B}}_{\mathrm{s}}^0{\pi }^{\pm }$ in proton-proton collisions at $\sqrt{s}=$ 8 TeV

A search for resonance-like structures in the ${\mathrm{B}}_{\mathrm{s}}^0{\pi }^{\pm }$ invariant mass spectrum is performed using proton-proton collision data collected by the CMS experiment at the LHC at $\sqrt{s}=$ 8 TeV, corresponding to an integrated luminosity of 19.7 fb${}^{-1}$. The ${\mathrm{B}}_{\mathrm{s}}^0$ mesons are reconstructed in the decay chain ${\mathrm{B}}_{\mathrm{s}}^0\to \mathrm{J}\mathrm{/}\psi \varphi$, with $\mathrm{J}\mathrm{/}\psi \to {\mu }^{+}{\mu }^{-}$ and $\varphi \to {\mathrm{K}}^{+}{\mathrm{K}}^{-}$. The ${\mathrm{B}}_{\mathrm{s}}^0{\pi }^{\pm }$ invariant mass distribution shows no statistically significant peaks for different selection requirements on the reconstructed ${\mathrm{B}}_{\mathrm{s}}^0$ and ${\pi }^{\pm }$ candidates. Upper limits are set on the relative production rates of the X(5568) and ${\mathrm{B}}_{\mathrm{s}}^0$ states times the branching fraction of the decay $\mathrm{X}(5568{)}^{\pm }\to {\mathrm{B}}_{\mathrm{s}}^0{\pi }^{\pm }$. In addition, upper limits are obtained as a function of the mass and the natural width of possible exotic states decaying into ${\mathrm{B}}_{\mathrm{s}}^0{\pi }^{\pm }$.