Using a 4.19 fb -1 data sample collected with the CLEO II detector at the Cornell Electron Storage Ring, we have searched for dipion transitions between pairs of Y resonances at center of mass energies E c.m. = 10.58 GeV and E c.m. = 10.52GeV. We obtain the 90% confidence level upper limits B(Y(4S) →Y(2S)π + π - )<3.9×10 -4 and B(Y(4S)→Y(1S)π + π - )<1.2×10 -4 . We also observe the transitions Y(3S)→Y(1S)π + π - , Y(3S)→Y(2S)π + π - , and Y(2S)→Y(1S)π + π - , from which we measure the cross sections for the radiative processes e + e - →Y(3S)γ and e + e - →Y(2S)γ. We obtain σ ee→Y(3S)γ = (17.8±3.0±1.7) pb and σ ee→Y(2S)γ =(15.5±1.3±1.4) pb at E c.m. = 10.58 GeV, and σ ee→Y(3S)γ =(27.3±5.0±2.6) pb and σ ee→Y(2S)γ =(16.3±1.8±1.5) pb at E c.m. = 10.52 GeV, which we compare with theoretical predictions.
|Journal||Physical Review D|
|Publication status||Published - 1999 Dec 1|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)