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Updated: Mar 19, 2026
07:53
Measuring the Time-Evolution of Nanoscale Materials with Stopped-Flow and Small-Angle Neutron Scattering
Published on: August 6, 2021
2.8K
Measurement of the Neutron Lifetime by Counting Trapped Protons.
F E Wietfeldt1, M S Dewey2, D M Gilliam2
1Tulane University, New Orleans, LA 70118.
Summary
Scientists precisely measured the neutron lifetime using a novel in-beam method. This study determined the neutron lifetime to be 886.8 seconds, offering the most accurate result to date for this fundamental constant.
Area of Science:
- Nuclear Physics
- Particle Physics
- Metrology
Background:
- The neutron lifetime is a fundamental constant in physics.
- Previous measurements have yielded a range of values, contributing to the 'proton lifetime puzzle'.
- Precise neutron lifetime measurements are crucial for understanding fundamental forces and particle physics.
Purpose of the Study:
- To determine the neutron lifetime with unprecedented precision.
- To refine the value of this fundamental constant.
- To contribute to resolving discrepancies in current physics models.
Main Methods:
- Utilizing an in-beam neutron decay measurement technique.
- Employing a quasi-Penning trap to capture decay recoil protons.
- Measuring absolute neutron beam fluence via capture in a lithium-fluoride (LiF) foil detector with known efficiency.
Main Results:
- The neutron lifetime was measured to be τn = (886.8 ± 1.2 ± 3.2) seconds.
- The result incorporates both statistical and systematic uncertainties.
- This represents the most precise neutron lifetime determination to date using an in-beam method.
Conclusions:
- The study provides a highly precise value for the neutron lifetime.
- This improved measurement will aid in further theoretical and experimental investigations in particle physics.
- The in-beam method offers a promising avenue for future high-precision measurements.
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