Abstract
We study the electromagnetic Dalitz decay J/ψ→e+e−η and search for dielectron decays of a dark gauge boson (γ′) in J/ψ→γ′η with the two η decay modes η→γγ and η→π+π−π0 using (1310.6±7.0)×106 J/ψ events collected with the BESIII detector. The branching fraction of J/ψ→e+e−η is measured to be (1.43±0.04(stat)±0.06(syst))×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 Λ=2.84±0.11(stat)±0.08(syst) GeV/c2. We find no evidence of γ′ production and set 90% confidence level upper limits on the product branching fraction B(J/ψ→γ′η)×B(γ′→e+e−) as well as the kinetic mixing strength between the standard model photon and γ′ in the mass range of 0.01≤mγ′≤2.4 GeV/c2.1 MoreReceived 8 October 2018DOI:https://doi.org/10.1103/PhysRevD.99.012006Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasMagnetic momentParticle decaysParticles & Fields
Highlights
The study of electromagnetic (EM) Dalitz decays of a vector meson (V 1⁄4 ρ; ω; φ; J=ψ) into a pseudoscalar meson (P 1⁄4 π0; η; η0) and a lepton-pair, V → lþl−P (l 1⁄4 e, μ), plays an important role in revealing the structure of hadrons and the interaction mechanism between photons and hadrons [1]
We study the electromagnetic Dalitz decay J=ψ → eþe−η and search for dielectron decays of a dark gauge boson (γ0) in J=ψ → γ0η with the two η decay modes η → γγ and η → πþπ−π0 using ð1310.6 Æ 7.0Þ × 106 J=ψ events collected with the BESIII detector
We present a study of the EM Dalitz decays J=ψ → eþe−η and search for dielectron decays of a dark photon through J=ψ → γ0η using ð1310.6Æ7.0Þ×106 J=ψ events collected with the BESIII detector [15]
Summary
The study of electromagnetic (EM) Dalitz decays of a vector meson (V 1⁄4 ρ; ω; φ; J=ψ) into a pseudoscalar meson (P 1⁄4 π0; η; η0) and a lepton-pair, V → lþl−P (l 1⁄4 e, μ), plays an important role in revealing the structure of hadrons and the interaction mechanism between photons and hadrons [1]. The TFFs of light mesons contribute to the hadronic light-by-light (HLBL) corrections [3] to the theoretical determination of the muon anomalous magnetic moment, aμ 1⁄4 ðgμ − 2Þ=2, which provides a low-energy test of the completeness of the standard model (SM) [4,5] It can directly be accessible by comparing the mlþl− spectrum of Dalitz decays V → lþl−P with that of the pointlike QED prediction [1]. We present a study of the EM Dalitz decays J=ψ → eþe−η and search for dielectron decays of a dark photon through J=ψ → γ0η using ð1310.6Æ7.0Þ×106 J=ψ events collected with the BESIII detector [15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
