A meta-analysis of neutron lifetime measurements

Abstract

Abstract We calculate the median as well as weighted mean central estimates for the neutron lifetime from a subset of measurements compiled in the 2019 update of the Particle Data Group (PDG). We then reconstruct the error distributions for the residuals using three different central estimates and then check for consistency with a Gaussian distribution. We find that although the error distributions using the weighted mean as well as median estimate are consistent with a Gaussian distribution, the Student’s $t$ and Cauchy distribution provide a better fit. This median statistic estimate of the neutron lifetime from these measurements is given by $881.5 \pm 0.47$ seconds. This can be used as an alternate estimate of the neutron lifetime. We also note that the discrepancy between beam and bottle-based measurements using median statistics of the neutron lifetime persists with a significance between 4 $\sigma$ and 8 $\sigma$, depending on which combination of measurements is used.