Space-based measurements of neutron lifetime: Approaches to resolving the neutron lifetime anomaly

Free neutrons have a measured lifetime of 880 s, but disagreement between existing laboratory measurements of similar to 10 s have persisted over many years. This uncertainty has implications for multiple physics disciplines, including standard-model particle physics and Big-Bang nucleosynthesis. Space-based neutron lifetime measurements have been shown to be feasible using existing data taken at Venus and the Moon, although the uncertainties for these measurements of tens of seconds prevent addressing the current lifetime discrepancy. We investigate the implementation of a dedicated space-based experiment that could provide a competitive and independent lifetime measurement. We considered a variety of scenarios, including measurements made from orbit about the Earth, Moon, and Venus, as well as on the surface of the Moon. For a standard-sized neutron detector, a measurement with three-second statistical precision can be obtained from Venus orbit in less than a day; a one-second statistical precision can be obtained from Venus orbit in less than a week. Similarly precise measurements in Earth orbit and on the lunar surface can be acquired in less than 40 days (three-second precision) and similar to 300 days (one-second precision). Systematic uncertainties that affect a space-based neutron lifetime measurement are investigated, and the feasibility of developing such an experiment is discussed.

Automated summary

The study explores the feasibility of space-based neutron lifetime measurements using data from Venus and the Moon, proposing a dedicated experiment for competitive and independent measurements. Measurements from Venus orbit can achieve statistical precision of three seconds in less than a day, while similar precise results can be obtained in Earth orbit and on the lunar surface, demonstrating the potential of such a space experiment.