Download or read book Observation of the Bottomonium Ground State in the Decay Y 3S to Ynb written by and published by . This book was released on 2008 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors report the results of a search for the bottomonium ground state [eta]{sub b}(1S) in the photon energy spectrum with a sample of (109 ± 1) million of [Upsilon](3S) recorded at the [Upsilon](3S) recorded at the [Upsilon](3S) energy with the BABAR detector at the PEP-II B factory at SLAC. They observe a peak in the photon energy spectrum at E{sub [gamma]} = 921.2{sub -2.8}{sup +2.1}(stat) ± 2.4(syst) MeV with a significance of 10 standard deviations. They interpret the observed peak as being due to monochromatic photons from the radiative transition [Upsilon](3S) → {gamma} [eta]{sub b}(1S). This photon energy corresponds to an [eta]{sub b}(1S) mass of 9388.9{sub -2.3}{sup +3.1}(stat) ± 2.7(syst) MeV/c2. The hyperfine [Upsilon](1S)-[eta]{sub b}(1S) mass splitting is 71.4{sub -3.1}{sup +2.3}(stat) ± 2.7(syst) MeV/c2. The branching fraction for this radiative [Upsilon](3S) decay is estimated to be (4.8 ± 0.5(stat) ± 1.2(syst)) x 10−4.

Download or read book Observation of the Bottomonium Ground State Eta b at BaBar written by and published by . This book was released on 2008 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present the first observation of the bottomonium ground state [eta]{sub b}(1S) in the photon energy spectrum using a sample of (109 ± 1) million of [Upsilon](3S) events recorded at the [Upsilon](3S) energy with the BaBar detector at the PEP-II B factory at SLAC. A peak at E{sub [gamma]} = 921.2{sub -2.8}{sup +2.1}(stat) ± 2.4(syst) MeV observed with a significance of 10 standard deviations in the photon energy spectrum is interpreted as being due to the radiative transition [Upsilon](3S) → {gamma} [eta]{sub b}(1S). This photon energy corresponds to an [eta]{sub b}(1S) mass of 9388.9{sub -2.3}{sup +3.1}(stat) ± 2.7(syst) MeV/c2. The hyperfine [Upsilon](1S)-[eta]{sub b}(1S) mass splitting is 71.4{sub -3.1}{sup +2.3}(stat) ± 2.7(syst) MeV/c2. The branching fraction for this radiative [Upsilon](3S) decay is obtained as (4.8 ± 0.5(stat) ± 1.2(syst)) x 10−4.