Studies of $$mathrm B ^*_mathrm s2(5840)^0 $$Bs2∗(5840)0 and $$mathrm B _mathrm s1(5830)^0 $$Bs1(5830)0 mesons including the observation of the $$mathrm B ^*_mathrm s2(5840)^0 ightarrow mathrm B ^0 mathrm K ^0_mathrm S $$Bs2∗(5840)0→B0KS0 decay in proton-proton collisions at $$sqrts=8, ext TeV $$s=8TeV

Measurements of B-s2*(5840)(0) and B-s1(5830)(0) mesons are performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of 19.6 fb(-1), collected with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV. The analysis studies P-wave B-s(0) meson decays into B(*)(+)K(-)and B(*)K-0(S)0, where the B+ and B-0 mesons are identified using the decays B+ -> J/psi K+ and B-0 -> J/psi K* (892)(0). The masses of the P-wave B-s(0) meson states are measured and the natural width of the B-s2*(5840)(0) state is determined. The first measurement of the mass difference between the charged and neutral B* mesons is also presented. The B-s2*(5840)(0) decay to (BKS0)-K-0 is observed, together with a measurement of its branching fraction relative to the B-s2*(5840)(0) -> B+K- decay.