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

2016/09/06 by Ulrich Ellwanger, Stefano Moretti, Ellwanger, Ulrich +1 · 2 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies

paper · doi:10.48550/arxiv.1609.01669

openalex publication_date 2016/09/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the ⁸Be 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.

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• Flavor specific chiral U(1)_X framework for explaining the ATOMKI anomaly
• Abnormal dense and dilute nuclear systems

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