Evidence for the η[subscript b](1S) Meson in Radiative Υ(2S) Decay
We have performed a search for the η[subscript b](1S) meson in the radiative decay of the Υ(2S) resonance using a sample of 91.6×10[superscript 6] Υ(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energ...
| Main Authors: | , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Physical Society
2010
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| Online Access: | http://hdl.handle.net/1721.1/54711 https://orcid.org/0000-0002-7586-7253 https://orcid.org/0000-0002-8667-5660 |
| Summary: | We have performed a search for the η[subscript b](1S) meson in the radiative decay of the Υ(2S) resonance using a sample of 91.6×10[superscript 6] Υ(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E[subscript γ]=609.3[subscript -4.5][superscript +4.6](stat)±1.9(syst) MeV, corresponding to an η[subscript b](1S) mass of 9394.2-4.9[superscript +4.8](stat)±2.0(syst) MeV/c[superscript 2]. The branching fraction for the decay Υ(2S)→γη[subscript b](1S) is determined to be [3.9±1.1(stat)[subscript -0.9][superscript +1.1](syst)]×10[superscript -4]. We find the ratio of branching fractions B[Υ(2S)→γη[subscript b](1S)]/B[Υ(3S)→γη[subscript b](1S)]=0.82±0.24(stat)[subscript -0.19][superscript +0.20](syst). |
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