Measurement of η′ → π<SUP>+</SUP>π<SUP>-</SUP><i>e</i><SUP>+</SUP><i>e</i><SUP>-</SUP> and η′ → π<SUP>+</SUP>π<SUP>-</SUP>μ<SUP>+</SUP>μ<SUP>-</SUP>


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Ablikim M., Achasov M. N., Albayrak O., Ambrose D. J., An F. F., An Q., ...More

PHYSICAL REVIEW D, vol.87, no.9, 2013 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 87 Issue: 9
  • Publication Date: 2013
  • Doi Number: 10.1103/physrevd.87.092011
  • Journal Name: PHYSICAL REVIEW D
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Bursa Uludag University Affiliated: No

Abstract

Based on a sample of 225.3 million J/psi events accumulated with the BESIII detector at the BEPCII, the decays of eta' -> pi(+)pi(-) l(+)l(-) are studied via J/psi -> gamma eta'. A clear eta' signal is observed in the pi(+)pi(-) e(+)e(-) mass spectrum, and the branching fraction is measured to be B(eta' -> pi(+)pi(-) e(+)e(-)) = (2.11 +/- 0.12(stat) +/- 0.14(syst)) x 10(-3), which is in good agreement with theoretical predictions and the previous measurement, but is determined with much higher precision. No eta' signal is found in the pi(+)pi(-) mu(+)mu(-) mass spectrum, and the upper limit is determined to be B(eta' -> pi(+)pi(-) mu(+)mu(-)) < 2.9 x 10(-5) at the 90% confidence level.