PNNL

Abstract

We report the observation of the hb(1P) and hb(2P) spin-singlet bottomonium states produced in the reaction e+e- ! hb(nP)*+*- with significances of 5.5 * and 11.2 *, respectively. We find that M[hb(1P)] = (9898.25±1.06+1.03 -1.07 )MeV/c2 and M[hb(2P)] = (10259.76±0.64+1.43 -1.03 )MeV/c2, which correspond to measurements of the P-wave hyperfine splittings *MHF = (1.62 ± 1.52)MeV/c2 and (0.48+1.57 -1.22)MeV/c2, respectively. We also report measurements of the cross sections for e+e- ! hb(nP)*+*- relative to the cross section for the e+e- ! *(2S)*+*- reaction. These results are obtained from a 121.4 fb-1 data sample collected with the Belle detector near the *(5S) resonance at the KEKB asymmetric-energy e+e- collider.