CP -violating decays of the pseudoscalars η and η′ and their connection to the electric dipole moment of the neutron

© 2017 American Physical Society. Using the present upper bound on the neutron electric dipole moment, we give an estimate for the upper limit of the CP-violating couplings of the η(η′) to the nucleon. Using this result, we then derive constraints on the CP-violating η(η′)ππ couplings, which define the two-pion CP-violating decays of the η and η′ mesons. Our results are relevant for the running and planned measurements of rare decays of the η and η′ mesons by the GlueX Collaboration at JLab and the LHCb Collaboration at CERN.