Title

Υ dipion transitions at energies near the Υ(4S)

Document Type

Article

Publication Date

3-1-1999

Abstract

Using a 4.19 fb 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 = 10.58 GeV and E = 10.52GeV. We obtain the 90% confidence level upper limits B(Υ(4S) →Υ (2S) π π )<3.9×10 and B(Υ(4S)→Υ(1S)π π )<1.2×10 . We also observe the transitions Υ(2S)→Υ(1S)π π , Υ(3S)→Υ(2S)π π , and Υ(2S)→Υ(1S)π π , from which we measure the cross sections for the radiative processes e e →Υ(2S)γ and e e →Υ(2S)γ. We obtain σ = (17.8±3.0±1.7)pb and = (15.5±1.3±1.4) pb at E = 10.58 GeV, and = (27.3 ±5.0±2.6) pb and = (16.3±1.8±1.5) pb at E = 10.52 GeV, which we compare with theoretical predictions. ©1999 The American Physical Society. -1 + - -4 + - -4 + - + - + - + - + - c.m. c.m. ee→Υ(3S)γ ee→Υ(2S)γ c.m. ee→Υ(3S)γ ee→Υ(2S)γ c.m.

Publication Name

Physical Review D - Particles, Fields, Gravitation and Cosmology

Volume Number

59

First Page

1

Last Page

8

Issue Number

5

Article

052003

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