Study of the Dalitz decay J/psi -> e(+)e(-)eta
Yükleniyor...
Dosyalar
Tarih
2019-01-09
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
AMER PHYSICAL SOC
Erişim Hakkı
info:eu-repo/semantics/openAccess
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).
Açıklama
Anahtar Kelimeler
DARK PHOTON, ETA-E(+)E(-), EMISSION, SEARCH, MESON, OMEGA, PAIR, PHI, ETA
Kaynak
PHYSICAL REVIEW D
WoS Q Değeri
Q1
