First observation of the isospin violating decay <i>J</i>/ψ → Λ(Σ)over-bar<SUP>0</SUP> + c.c.


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Ablikim M., Achasov M. N., Ambrose D. J., An F. F., An Q., An Z. H., ...Daha Fazla

PHYSICAL REVIEW D, cilt.86, sa.3, 2012 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 86 Sayı: 3
  • Basım Tarihi: 2012
  • Doi Numarası: 10.1103/physrevd.86.032008
  • Dergi Adı: PHYSICAL REVIEW D
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Bursa Uludağ Üniversitesi Adresli: Hayır

Özet

Using a sample of (225.2 +/- 2.8) x 10(6) J/psi events collected with the BESIII detector, we present results of a study of J/psi -> gamma Lambda(Lambda) over bar and report the first observation of the isospin violating decay J/psi -> Lambda(Sigma) over bar (0) + c.c., in which (Sigma) over bar (0) decays to gamma (Lambda) over bar. The measured branching fractions are B(J/psi -> (Lambda) over bar Sigma(0)) = (1.46 +/- 0.11 +/- 0.12) x 10(-5) and B(J/psi -> Lambda(Sigma) over bar (0)) = (1.37 +/- 0.12 +/- 0.11) x 10(-5). We search for Lambda(1520) -> gamma Lambda decay, and find no evident signal, and an upper limit for the product branching fraction B(J/psi -> Lambda(Lambda) over bar (1520) + c.c) x B(Lambda(1520) -> gamma Lambda) < 4.1 x 10(-6) is set at the 90% confidence level. We also report the observation of eta(c) -> Lambda<(Lambda)over bar> in J/psi -> gamma eta(c), eta(c) -> Lambda(Lambda) over bar and measure the branching fraction B(eta(c) -> Lambda(Lambda) over bar) = (1.16 +/- 0.12(stat) +/- 0.19(syst) +/- 0.28(PDG)) x 10(-3).