We present new measurements of photon energies and branching fractions for the radiative transitions Y(2S)→γχb(J=0,1,2)(1P). The masses of the χb states are determined from the measured radiative photon energies. The ratio of mass splittings between the χb substates, r≡(MJ=2-MJ=1)/(MJ=1-MJ=0), with M the χb mass, provides information on the nature of the bb̄ confining potential. We find r(1P)=0.542 ±0.022±0.024. This value is somewhat lower than the previous world average, but more consistent with the theoretical expectation that r(1P)<r(2P); i.e., that this mass splitting ratio is smaller for the χb(1P) states than for the χb(2P) states.
|Number of pages||5|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - 1999 Feb 1|
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics