Studies of B s 2 ∗ ( 5840 ) 0 and B s 1 ( 5830 ) 0 mesons including the observation of the B s 2 ∗ ( 5840 ) 0 → B 0 K S 0 decay in proton-proton collisions at s = 8 TeV

Abstract

Measurements of $B_{s2}^{\ast }{\left(5840\right)}^0$ and $B_{s1}{\left(5830\right)}^0$ mesons are performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of , collected with the CMS detector at the LHC at a centre-of-mass energy of $8\text{TeV}$ . The analysis studies P-wave $B_s^0$ meson decays into $B^{(\ast )+}{K}^{-}$ and $B^{(\ast )0}{K}_S^0$ , where the $B^{+}$ and $B^0$ mesons are identified using the decays $B^{+}\to J/\psi K^{+}$ and $B^0\to J/\psi K^{\ast }{\left(892\right)}^0$ . The masses of the P-wave $B_s^0$ meson states are measured and the natural width of the $B_{s2}^{\ast }{\left(5840\right)}^0$ state is determined. The first measurement of the mass difference between the charged and neutral $B^{\ast }$ mesons is also presented. The $B_{s2}^{\ast }{\left(5840\right)}^0$ decay to $B^0{K}_S^0$ is observed, together with a measurement of its branching fraction relative to the $B_{s2}^{\ast }{\left(5840\right)}^0\to B^{+}{K}^{-}$ decay.

Keywords: CMS; Experimental results; Hadron spectroscopy; Heavy flavour spectroscopy; Physics; b hadrons.