APS » Journals » Phys. Rev. Lett. » Accepted Papers » First observation of the decay $B^{\ast}_{s2}(5840)^0 \rightarrow B^{\ast} ^+K^-$ and studies of excited $B_s^0$ mesons

First observation of the decay B\asts2(5840)^0 \rightarrow B\ast ^+K^- and studies of excited B_s^0 mesons

Accepted

Properties of the orbitally excited (L=1) states are studied using 1.0 of p p collisions at \sqs = 7 collected with the detector. The first observation of the Bs2*(5840)0 meson decaying to \Bus \Km is reported, and the corresponding branching fraction measured relative to the \Bu \Km decay mode. The \Bs1(5830)0 \Bus \Km decay is observed as well. The width of the Bs2*(5840)0 state is measured for the first time and the masses of the two states are determined with the highest precision to date. The observation of the Bs2*(5840)0 \Bus\Km decay favours the spin-parity assignment JP = 2+ for the Bs2*(5840)0 meson. In addition, the most precise measurement of the mass difference m(\Bus)-m(\Bu) = 45.01 0.30  (stat) 0.23  (syst) \mevcc is obtained.