Search for the Neutron Decay n→X+γ, Where X is a Dark Matter Particle

Z. Tang, M. Blatnik, L. J. Broussard, J. H. Choi, S. M. Clayton, C. Cude-Woods, S. Currie, D. E. Fellers, E. M. Fries, P. Geltenbort, F. Gonzalez, K. P. Hickerson, T. M. Ito, C. Y. Liu, S. W.T. Macdonald, M. Makela, C. L. Morris, C. M. O'Shaughnessy, R. W. Pattie, B. PlasterD. J. Salvat, A. Saunders, Z. Wang, A. R. Young, B. A. Zeck

Research output: Contribution to journalArticlepeer-review


Fornal and Grinstein recently proposed that the discrepancy between two different methods of neutron lifetime measurements, the beam and bottle methods, can be explained by a previously unobserved dark matter decay mode, n→X+γ. We perform a search for this decay mode over the allowed range of energies of the monoenergetic γ ray for X to be dark matter. A Compton-suppressed high-purity germanium detector is used to identify γ rays from neutron decay in a nickel-phosphorous-coated stainless-steel bottle. A combination of Monte Carlo and radioactive source calibrations is used to determine the absolute efficiency for detecting γ rays arising from the dark matter decay mode. We exclude the possibility of a sufficiently strong branch to explain the lifetime discrepancy with 97% confidence.

Original languageEnglish (US)
Article number022505
JournalPhysical review letters
Issue number2
StatePublished - Jul 11 2018
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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