Observation of Orbitally Excited B_s Mesons

TL;DR

This paper reports the first observation of two narrow orbitally excited B_s meson states, measuring their masses using data from proton-antiproton collisions at Fermilab, providing new insights into heavy meson spectroscopy.

Contribution

First observation and mass measurement of two narrow orbitally excited B_s mesons using collider data and specific decay channels.

Findings

Masses of B_{s1} and B_{s2}^* measured

First experimental evidence of these excited states

Results consistent with theoretical predictions

Abstract

We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.