Search for a Structure in the $B_s^0{\pi }^{\pm }$ Invariant Mass Spectrum with the ATLAS Experiment

A search for the narrow structure, $X(5568)$, reported by the D0 Collaboration in the decay sequence $X\to B_s^0{\pi }^{\pm }$, $B^0_s \to J/\psi\phi$, is presented. The analysis is based on a data sample recorded with the ATLAS detector at the LHC corresponding to 4.9 fb${}^{-1}$ of $pp$ collisions at 7 TeV and 19.5 fb${}^{-1}$ at 8 TeV. No significant signal was found. Upper limits on the number of signal events, with properties corresponding to those reported by D0, and on the $X$ production rate relative to $B_s^0$ mesons, ${\rho }_X$, were determined at 95% confidence level. The results are $N(X)<382$ and ${\rho }_X<0.015$ for $B_s^0$ mesons with transverse momenta above 10 GeV, and $N(X)<356$ and ${\rho }_X<0.016$ for transverse momenta above 15 GeV. Limits are also set for potential $B_s^0{\pi }^{\pm }$ resonances in the mass range 5550 MeV to 5700 MeV.