The 17 mev anomaly in beryllium decays and u(1) portal to dark matter

Chian Shu Chen, Guey Lin Lin, Yen Hsun Lin, Fanrong Xu

Research output: Contribution to journalConference articlepeer-review


The experiment of Krasznahorkay et al observed the transition of a 8Be excited state to its ground state and accompanied by an emission of e+e pair with 17 MeV invariant mass. This 6.8σ anomaly can be fitted by a new light gauge boson. We consider the new particle as a U(1) gauge boson, Z0, which plays as a portal linking dark sector and visible sector. In particular, we study the new U(1) gauge symmetry as a hidden or non-hidden group separately. The generic hidden U(1) model, referred to as dark Z model, is excluded by imposing various experimental constraints. On the other hand, a non-hidden Z0 is allowed due to additional interactions between Z0 and Standard Model fermions. We also study the implication of the dark matter direct search on such a scenario. We found the search for the DM-nucleon scattering cannot probe the parameter space that is allowed by 8Be-anomaly for the range of DM mass above 500 MeV. However, the DM-electron scattering for DM between 20 and 50 MeV can test the underlying U(1) portal model using the future Si and Ge detectors with 5e threshold charges.

Original languageEnglish
JournalProceedings of Science
Publication statusPublished - 2017 Jan 1
Event2017 European Physical Society Conference on High Energy Physics, EPS-HEP 2017 - Venice, Italy
Duration: 2017 Jul 52017 Jul 12

All Science Journal Classification (ASJC) codes

  • General


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