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New evaluation of neutron lifetime from UCN storage experiments and beam experiments

2011/04/21 by A. P. Serebrov, A. П. Серебров, Serebrov, A. P. +3
Physics and Astronomy · #Atomic and Subatomic Physics Research #FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear Physics and Applications #Quantum, superfluid, helium dynamics #nucl-ex

paper · pdf · doi:10.48550/arxiv.1104.4238

7 pages, 4 figures, 2 tables

arxiv created 2011/04/21 · openalex publication_date 2011/04/21 · arxiv updated 2011/04/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The analysis of experiments on measuring neutron lifetime has been made. The latest most accurate result of measuring neutron lifetime [Phys. Lett. B 605, 72 (2005)] 878.5 ± 0.8 s differs from the world average value [Phys. Lett. B 667, 1 (2008)] 885.7 ± 0.8 s by 6.5 standard deviations. In view of this both the analysis and the Monte Carlo simulation of experiments [Phys. Lett. B 483, 15 (2000)] and [Phys. Rev. Lett. 63, 593 (1989)] have been performed. Systematic errors about -6 s have been found in both experiments. The table of results of neutron lifetime measurements is given after corrections and additions have been made. A new world average value of neutron lifetime makes up 880.0 ± 0.9 s. Here is also presented a separate analysis of experiments on measuring neutron lifetime with UCN and experiments on the beams. The average neutron lifetime for experiments with UCN is equal to 879.3(0.6) s, while for experiments on the beams it is equal to 889.1(2.9) s. The present difference of average values for both groups is (3.3 sigma) and needs consideration. The contribution of beam experiments into the world average value is not high, therefore it does not influence the above analysis. However, it is an independent problem to be solved. It seems desirable that the precision of beam experiments should be enhanced.

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