Evidence for the eta{sub b}(1S) Meson in Radiative UPSILON(2S) Decay

Journal Article · Fri Oct 16 04:00:00 EDT 2009 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.103.161801· OSTI ID:21370756

Aubert, B; Bona, M; Karyotakis, Y; Lees, J P; Poireau, V; Prencipe, E; Prudent, X; Tisserand, V ^[1]; Garra Tico, J; Grauges, E ^[2]; Lopez, L; Palano, A; Pappagallo, M ^[3]; Eigen, G; Stugu, B; Sun, L ^[4]; Battaglia, M; Brown, D N; Kerth, L T; Kolomensky, Yu G ^[5]

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1. Laboratoire de Physique des Particules, IN2P3/CNRS et Universite de Savoie, F-74941 Annecy-Le-Vieux (France)
2. Universitat de Barcelona, Facultat de Fisica, Departament ECM, E-08028 Barcelona (Spain)
3. INFN Sezione di Bari, I-70126 Bari (Italy)
4. University of Bergen, Institute of Physics, N-5007 Bergen (Norway)
5. Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720 (United States)

We have performed a search for the eta{sub b}(1S) meson in the radiative decay of the UPSILON(2S) resonance using a sample of 91.6x10{sup 6} UPSILON(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{sub {gamma}}=609.3{sub -4.5}{sup +4.6}(stat)+-1.9(syst) MeV, corresponding to an eta{sub b}(1S) mass of 9394.2{sub -4.9}{sup +4.8}(stat)+-2.0(syst) MeV/c{sup 2}. The branching fraction for the decay UPSILON(2S)->gammaeta{sub b}(1S) is determined to be [3.9+-1.1(stat){sub -0.9}{sup +1.1}(syst)]x10{sup -4}. We find the ratio of branching fractions B[UPSILON(2S)->gammaeta{sub b}(1S)]/B[UPSILON(3S)->gammaeta{sub b}(1S)]=0.82+-0.24(stat){sub -0.19}{sup +0.20}(syst).

• OSTI ID: 21370756
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 16 Vol. 103; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

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