Study of the Dalitz decay <i>J</i>/ψ → <i>e</i><SUP>+</SUP><i>e</i><SUP>-</SUP>η


Ablikim M., Achasov M. N., Ahmed S., Albrecht M., Alekseev M., Amoroso A., ...Daha Fazla

PHYSICAL REVIEW D, cilt.99, sa.1, 2019 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 99 Sayı: 1
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1103/physrevd.99.012006
  • Dergi Adı: PHYSICAL REVIEW D
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Bursa Uludağ Üniversitesi Adresli: Hayır

Özet

We study the electromagnetic Dalitz decay J/psi -> e(+)e(-)eta and search for dielectron decays of a dark gauge boson (gamma') in J/psi -> gamma'eta with the two q decay modes eta -> gamma gamma and eta -> pi(+)pi(-)pi(0) using (1310.6 +/- 7.0) x 10(6) J/psi events collected with the BESIII detector. The branching fraction of J/psi -> e(+)e(-)eta is measured to be (1.43 +/- 0.04(stat) +/- 0.06(syst)) x 10(-5), with a precision that is improved by a factor of 1.5 over the previous BESIII measurement. The corresponding dielectron invariant mass dependent modulus square of the transition form factor is explored for the first time, and the pole mass is determined to be Lambda = 2.84 +/- 0.11(stat) +/- 0.08(syst) GeV/c(2). We find no evidence of gamma' production and set 90% confidence level upper limits on the product branching fraction B(J/psi -> gamma'eta) x B(gamma' -> e(+)e(-)) as well as the kinetic mixing strength between the standard model photon and gamma' in the mass range of 0.01 <= m(gamma') <= 2.4 GeV/c(2).