New level of precision in study of neutron beta-decay -- Theoretical basics and experimental backgrounds

TL;DR

This paper introduces a novel theoretical approach to measure neutron lifetime with higher precision by analyzing neutron subsets based on spin and electron emission directions, supported by experimental data.

Contribution

It proposes an alternative concept of neutron beta decay for more accurate lifetime determination, including new weighting methods and analytical expressions validated by experimental data.

Findings

Weighted average neutron lifetime aligns with experimental results.

Analytical expressions relate neutron lifetimes to asymmetry parameters.

Conditions for future experiments to improve accuracy are outlined.

Abstract

The article provides a theoretical substantiation for a significant increase in the level of accuracy in determining the neutron lifetime using an alternative concept of neutron beta decay. Neutrons are distributed among different subsets depending on the sign of the scalar product of the neutron spin vector and momentum of the emitted electron during decay. Therefore, the neutron lifetime can be determined separately for each of the subsets as the inverse frequency of its decay, which is to be averaged over the number of neutrons in this subset. The total neutron lifetime on the total set of neutrons is calculated by averaging the partial (basic) lifetimes, considering their weights. The weights of the basic lifetimes are calculated for two weighing methods, leading, respectively, to the so-called lifetime of "nonpolarized" neutrons, the weighted average lifetime of neutrons and the central lifetime, i.e. the arithmetic mean for the basic lifetimes of neutrons. The dependence between different average neutron lifetimes through the integral asymmetry parameter calculated by using known experimental data leads to simple analytical expressions. The numerical estimate of the weighted average neutron lifetime gives a value that is in good agreement with the results of well-known experiments, which proves the validity of the proposed concept of neutron beta decay. This article includes necessary conditions for a new experiment to bring the neutron lifetime determination to a new level of accuracy.