Using a sample of 771.6 × 106 ?(4S) decays collected by the Belle experiment at the KEKB e +e - collider, we observe for the first time the transition ?(4S) ? ?hb(1P) with the branching fraction B[?(4S) ? ?hb(1P)] = (2.18 ± 0.11 ± 0.18) × 10-3 and we measure the hb(1P) mass Mhb(1P ) = (9899.3 ± 0.4 ± 1.0) MeV/c 2 , corresponding to the hyperfine splitting ?MHF (1P) = (0.6 ± 0.4 ± 1.0) MeV/c 2 . Using the transition hb(1P) ? ??b(1S), we measure the ?b(1S) mass M?b(1S) = (9400.7 ± 1.7 ± 1.6) MeV/c 2 , corresponding to ?MHF (1S) = (59.6 ± 1.7 ± 1.6) MeV/c 2 , the ?b(1S) width G?b(1S) = (8+6 -5 ± 5) MeV/c 2 and the branching fraction B[hb(1P) ? ??b(1S)] = (56 ± 8 ± 4)%.
Revised: March 18, 2016 |
Published: October 1, 2015
Citation
Tamponi U., R. Mussa, A. Abdesselam, H. Aihara, K. Arinstein, D.M. Asner, and H. Atmacan, et al. 2015.First observation of the hadronic transition ?(4S)??hb(1P) and new measurement of the hb(1P) and ?b(1S) parameters.Physical Review Letters 115, no. 14:Article No. 142001.PNNL-SA-112064.doi:10.1103/PhysRevLett.115.142001