Abstract
We present the first evidence for the production of Υ(1D) states in the four-photon cascade, Υ(3S) →γχb(2P), χb(2P)→γΥ(1D), Υ(1D) →γχb(1P), χb(1P)→γΥ(1S) , followed by the Υ(1S) annihilation into e+e- or μ+μ-. The signal has a significance of 10.2 standard deviations. The measured product branching ratio for these five decays, (2.5±0.5±0.5)×10-5, is consistent with the theoretical estimates. The data are dominated by the production of one Υ(1D) state consistent with the J=2 assignment. Its mass is determined to be (10161.1±0.6±1.6) MeV, which is consistent with the predictions from potential models and lattice QCD calculations. We also searched for Υ(3S)→γχb(2P), χb(2P) →γΥ(1D), followed by either Υ(1D)→ηΥ(1S) or Υ(1D)→π+π-Υ(1S). We find no evidence for such decays and set upper limits on the product branching ratios.
Original language | English (US) |
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Article number | 032001 |
Pages (from-to) | 032001-1-032001-7 |
Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |
Volume | 70 |
Issue number | 3 |
DOIs | |
State | Published - Aug 15 2004 |
Bibliographical note
Funding Information:Financial support provided by the National Natural Science Foundation of China (No. 51478454) and the special fund from the State Key Laboratory of Environmental Aquatic Chemistry (No. 13Z04ESPCT) are gratefully acknowledged.