Search for the decay J/ψ→γ+ invisible

Abstract

We search for J=ψ radiative decays into a weakly interacting neutral particle, namely an invisible particle, using the J=ψ produced through the process ψð3686Þ → π þ π − J=ψ in a data sample of ð448.1 AE 2.9Þ × 10 6 ψð3686Þ decays collected by the BESIII detector at BEPCII. No significant signal is observed. Using a modified frequentist method, upper limits on the branching fractions are set under different assumptions of invisible particle masses up to 1.2 GeV=c 2. The upper limit corresponding to an invisible particle with zero mass is 7.0 × 10 −7 at the 90% confidence level.

Feebly-interacting particles: FIPs 2020 workshop report

“…-BES III (IHEP) [252] The BESIII detector at BEPCII operates with variable beam energies in the τ -charm region. BESIII has collected a massive sample of quarkonia, and has performed multiple direct searches for FIPs and searches for rare decays that could be enhanced by FIPs [253][254][255][256], including ψ(3686) → π + π − J/ψ(γ X ), where X decays invisibly. Status: Active.…”

Crossing two-component dark matter models and implications for 511 keV $γ$-ray and XENON1T excesses

“…for semivisible decays. As we already see that sin θ h is severely constrained to be very small from h 1 invisible and exotic decays, so we ignore the constraints from BaBar [94,95], Belle [96,97] and BESIII [98] experiments for light h 2 invisible decays which are much weaker than the above ones. We only include constraints from h 2 visible and invisible decays at LEP [99,100] as shown in the red and yellow dashed lines of Fig.…”

The implication of $J/ψ\to (γ+ ){\rm invisible}$ for the effective field theories of neutrino and dark matter

“…In our fit to the experimental data we follow as closely as possible the experimental analysis [9]. We assume the events in each bin to be distributed following a Poisson distribution and thus the likelihood is given by…”

“…The CLEO-c [6], BaBar [7] and Belle [8] experiments have searched for J/ψ or Υ radiative decays into invisible particles. Recently, the BESIII collaboration performed a similar search for J/ψ using the data collected by the BESIII detector at Beijing Electron Positron Collider (BEPCII), and no signal was observed [9]. The BESIII collaboration interprets the invisible particle as a new CP-odd pseudoscalar and the upper limit on the branching fraction for a massless pseudoscalar is 7 × 10 −7 at the 90% confidence level (C.L.).…”

“…The neutral current interactions of neutrinos also lead to their pair productions. We thus investigate the three-body decays of J/ψ into a photon and a pair of neutrinos or DM particles, rather than the two-body decay of J/ψ which has been analyzed by BESIII [9]. Similar studies inspired by the Belle data were performed for the Υ radiative decay into DM pairs [12,13] and the invisible decay of dark photon or millicharged particle was also proposed through the e + e − collision at the BESIII detector [14,15].…”