Possible Explanation of the Electron Positron Anomaly at 17 MeV in ${}^{8}Be$ Transitions Through a Light Pseudoscalar

Abstract

We estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the ${}^{8}Be$ anomaly observed in the Atomki pair spectrometer experiment. The resulting couplings of A to up and down type quarks are about 0.3 times the coupling of the standard Higgs boson. Then constraints from K and B decays require that loop contributions to flavour changing vertices cancel at least at the 10% level. Constraints from beam dump experiments require the coupling of A to electrons to be larger than about 4 times the coupling of the standard Higgs boson, leading to a short enough A life time consistent with an explanation of the anomaly.

arXiv comment12 pages, discussion of nuclear shell model corrected, to appear in JHEP

References in corpus (11)

• Observation of Anomalous Internal Pair Creation in ${}^8$Be: A Possible Signature of a Light, Neutral Boson
• A taste of dark matter: Flavour constraints on pseudoscalar mediators
• ALPtraum: ALP production in proton beam dump experiments
• Particle Physics Models for the 17 MeV Anomaly in Beryllium Nuclear Decays
• Fundamental Physics at the Intensity Frontier
• Revisiting Scalar and Pseudoscalar Couplings with Nucleons
• Constraining the Axion Portal with B -> K l+ l-
• Realistic model for a fifth force explaining anomaly in ${}^{8}B{e}^{\ast }\to {}^{8}Be{e}^{+}{e}^{-}$ Decay
• The NMSSM lives: with the 750 GeV diphoton excess
• The new interaction suggested by the anomalous ${}^8$Be transition sets a rigorous constraint on the mass range of dark matter
• X(16.7) as the Solution of NuTeV Anomaly

Cited by in corpus (1)

• Model-independent bounds on light pseudoscalars from rare B-meson decays