First observation of a Upsilon(1D) state
Collaboration
12 pages
Published in:
- Phys.Rev.D 70 (2004) 032001
e-Print:
- hep-ex/0404021 [hep-ex]
Report number:
- CLNS-04-1866,
- CLEO-04-4
Experiments:
View in:
Citations per year
Abstract:
We present the first evidence for the production of Upsilon(1D) states in the four-photon cascade, Upsilon(3S)-->gamma chib(2P), chib(2P)-->gamma Upsilon(1D), Upsilon(1D)-->gamma chib(1P), chib(1P)-->gamma Upsilon(1S), followed by the Upsilon(1S) annihilation into e+e- or mu+mu-. 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)x10^(-5), is consistent with the theoretical estimates. The data are dominated by the production of one Upsilon(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 Upsilon(3S)-->gammachib(2P), chib(2P)-->gammaUpsilon(1D), followed by either Upsilon(1D)-->eta Upsilon(1S) or Upsilon(1D)-->pi+pi- Upsilon(1S). We find no evidence for such decays and set upper limits on the product branching ratios.- 14.40.Gx
- 13.20.Gd
- electron positron: colliding beams
- electron positron: annihilation
- Upsilon(10355): electroproduction
- Upsilon(10355): radiative decay
- Upsilon(10355): cascade decay
- upsilon mesons: hadron spectroscopy
- new particle: Upsilon(10161)
- angular momentum: 2
References(28)
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