text: While the neutron lifetime has been studied for decades, there currently exists a lack of consilience on its exact value, due to different results from two experimental methods ("bottle" versus "beam").
  The "neutron lifetime anomaly" was discovered after the refinement of experiments with ultracold neutrons. While the error margin was once overlapping, increasing refinement in technique which should have resolved the issue has failed to demonstrate convergence to a single value. The difference in mean lifetime values obtained as of 2014 was approximately 9 seconds. Further, a prediction of the value based on quantum chromodynamics as of 2018 is still not sufficiently precise to support one over the other.
  As explained by Wolchover (2018), the beam test would be incorrect if there is a decay mode that does not produce a proton. 
  On 13 October 2021 the lifetime from the bottle method was updated to  increasing the difference to 10 seconds below the beam method value of  and also on the same date a novel third method using data from the past NASA's Lunar prospector mission reported a value of  but with great uncertainty.
  Yet another approach similar to the beam method has been explored with the Japan Proton Accelerator Research Complex (J-PARC) but it is too imprecise at the moment to be of significance on the analysis of the discrepancy.