Determination of the number of J/ψ events with inclusive J/ψ decays

Abstract

Received 5 July 2016, Revised 26 August 2016 * Supported by National Key Basic Research Program of China (2015CB856700), National Natural Science Foundation of China (NSFC) (10805053, 11125525, 11175188, 11235011, 11322544, 11335008, 11425524) Abstract: A measurement of the number of J/ψ events collected with the BESIII detector in 2009 and 2012 is performed using inclusive decays of the J/ψ. The number of J/ψ events taken in 2009 is recalculated to be (223.7 ± 1.4) × 10 6 , which is in good agreement with the previous measurement, but with significantly improved precision due to improvements in the BESIII software. The number of J/ψ events taken in 2012 is determined to be (1086.9 ± 6.0) × 10 6 . In total, the number of J/ψ events collected with the BESIII detector is measured to be (1310.6 ± 7.0) × 10 6 , where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.

Study of J/ψ and ψ(3686) decay to ΛAblikim1, Ачасов2, Ahmed3 et al. 2017Phys. Rev. DSelf Cite

“…e þ e − → BB decays, are estimated with the data samples taken at the c.m. energies of 3.08 and 3.65 GeV, which have integrated luminosities of 30 and 44 pb −1 [18,19], respectively. By applying the same selection criteria, no event survives in the selection of J=ψ → BB, while in the selection of ψð3686Þ → BB, only a few events survive, and no obvious peak is observed in the Λ=Σ 0 mass region.…”

“…where N obs is the number of signal events minus peaking background, ϵ is the detection efficiency, which is estimated with MC simulation incorporating the cos θ distributions obtained in this analysis and the scale factors to account for the difference in efficiency between data and MC simulation as described below, B i is the product of branching fractions for the intermediate states in the cascade decay from the PDG [15] and N ψ is the total number of ψ events estimated by counting the inclusive hadronic events [18,19]. The corresponding detection efficiencies and the resultant branching fractions are also summarized in Table III.…”

“…[10]. In this paper, we report precise measurements of the branching fractions and α values for the decays ψ → BB, based on the data samples of ð1310.6 AE 7.0Þ × 10 6 J=ψ [18] and ð447.9 AE 2.9Þ × 10 6 ψð3686Þ [19,20] events collected with the BESIII detector at the BEPCII collider.…”

Study of η(1475) and X(1835) in radiative Ablikim1, Ачасов2, Ahmed3 et al. 2018Phys. Rev. DSelf Cite

“…In this paper, we present an analysis of the decay J/ψ → γγϕ, where the ϕ meson is reconstructed in the K þ K − final state, based on a sample of 1.31 × 10 9 J/ψ events [23] collected with the BESIII detector [24]. A GEANT4-based [25] Monte Carlo (MC) simulation software package is used to optimize the event selection criteria, estimate backgrounds and determine the detection efficiencies.…”

“…The systematic uncertainties on the branching fraction measurements are also subject to the uncertainties in the total number of J/ψ [23] events, the relevant branching fraction Bðϕ → K þ K − Þ from the PDG [5], kaon tracking, kaon PID, photon detection, the kinematic fit and the vetoes of π 0 , η and η 0 . The systematic uncertainties associated with the 5C kinematic fit are studied with the track helix parameter correction method, as described in Ref.…”