ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2010, vol. 82, p. -
Observation of an enhancement in e+e-→Υ(1S) πn+n-→Υ(2S)n+n- and (3S)n+n- production near s = 10.89 GeV
We measure the production cross sections for e+e -→Υ(1S)π+π-, Υ(2S)π+π-, and Υ(3S) π+π- as a function of √s between 10.83 GeV and 11.02 GeV. The data consist of 8.1fb-1 collected with the Belle detector at the KEKB e+e- collider. We observe enhanced production in all three final states that does not agree well with the conventional Υ(10860) line shape. A fit using a Breit-Wigner resonance shape yields a peak mass of [10888.4-2.6+2.7(stat)±1.2(syst)]MeV/c2 and a width of [30.7-7.0+8.3(stat)±3.1(syst)]MeV/c2. © 2010 The American Physical Society.