This Letter presents the first strong evidence for the resolution of the excited B mesons B1 and B as two separate states in fully reconstructed decays to B+(*)-. The mass of B1 is measured to be 5720.6±2.4±1.4 MeV/c2 and the mass difference M between B and B1 is 26.2±3.1±0.9 MeV/c2, giving the mass of the B as 5746.8±2.4±1.7 MeV/c2. The production rate for B1 and B mesons is determined to be a fraction (13.9±1.9±3.2)% of the production rate of the B+ meson.
Entire analysis and paper produced by PhD student Mark Williams under Ratoff's supervision. The first direct observation of B1 and B2* as independent states, the most precise measurement of their masses and the only measurement of the rate at which they are produced with respect to ground state B mesons. RAE_import_type : Journal article RAE_uoa_type : Physics