Constraints on the Dark Matter Interpretation $n \rightarrow \chi + e^+ e^-$ of the Neutron Decay Anomaly with the PERKEO II experiment

M. Klopf , E. Jericha , B. Märkisch , H. Saul , T. Soldner (1) , H. Abele

1 ILL - Institut Laue-Langevin

Discrepancies from in-beam- and in-bottle-type experiments measuring the neutron lifetime are on the 4σ standard deviation level. In a recent publication Fornal and Grinstein proposed that the puzzle could be solved if the neutron would decay on the one percent level via a dark decay mode, one possible branch being n→χ+e+e-. With data from the Perkeo II experiment we set limits on the branching fraction and exclude a one percent contribution for 95% of the allowed mass range for the dark matter particle.

Mots clés: 13.30.Ce; 12.15.Ji; 12.60.-i; 14.20.Dh; Nuclear Physics; n: lifetime; lifetime: measured; n: rare decay; n: semileptonic decay; particle: stability; electron: pair production; dark matter: mass: lower limit; n: branching ratio; branching ratio: upper limit; n: decay modes; anomaly; interpretation of experiments; experimental results; S017.5; S030UDM

Domaines: Physique des Hautes Energies - Expérience [hep-ex]; Physique des Hautes Energies - Phénoménologie [hep-ph]; Physique Nucléaire Expérimentale [nucl-ex]

M. Klopf, E. Jericha, B. Märkisch, H. Saul, T. Soldner, et al.. Constraints on the Dark Matter Interpretation $n \rightarrow \chi + e^+ e^-$ of the Neutron Decay Anomaly with the PERKEO II experiment. Physical Review Letters, 2019, 122 (22), pp.222503. ⟨10.1103/PhysRevLett.122.222503⟩. ⟨hal-02144179⟩