ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2016, vol. 94, 3, p. -
Observation of e+e- →η′J /ψ at center-of-mass energies between 4.189 and 4.600 GeV OBSERVATION of ... M. ABLIKIM et al.
© 2016 American Physical Society.The process e+e-→η′J/ψ is observed for the first time with a statistical significance of 8.6σ at center-of-mass energy s=4.226 GeV and 7.3σ at s=4.258 GeV using data samples collected with the BESIII detector. The Born cross sections are measured to be (3.7±0.7±0.3) and (3.9±0.8±0.3) pb at s=4.226 and 4.258 GeV, respectively, where the first errors are statistical and the second systematic. Upper limits at the 90% confidence level of the Born cross sections are also reported at other 12 energy points.