Can nuclear physics explain the anomaly observed in the internal pair production in the Beryllium-8 nucleus?

Abstract

Recently the experimentalists in [PRL 116, 042501 (2016)] announced observing an unexpected enhancement of the electron-positron pair production signal in one of the Beryllium-8 nuclear transitions. The following studies have been focused on possible explanations based on introducing new types of particle. In this work, we improve the nuclear physics modeling of the reaction by studying the pair emission anisotropy and the interferences between different multipoles in an effective field theory inspired framework, and examine their possible relevance to the anomaly. The connection between the previously measured on-shell photon production and the pair production in the same nuclear transitions is established. These improvements, absent in the original experimental analysis, should be included in extracting new particle's properties from the experiment of this type. We then study the possibility of using the nuclear transition form factor to explain the anomaly. The reduction of the anomaly's significance by simply rescaling our predicted event count is also investigated.

8 pages, 7 figures, 3 tables

References in corpus (3)

• Quantum Monte Carlo calculations of electromagnetic transitions in 8Be with meson-exchange currents derived from chiral effective field theory
• Protophobic Light Vector Boson as a Mediator to the Dark Sector
• The new interaction suggested by the anomalous ${}^8$Be transition sets a rigorous constraint on the mass range of dark matter

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