Colloquium: The neutron lifetime

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Reviews of Modern Physics

OSTI ID:1037070

Greene, Geoffrey L ^[1]; Wietfeldt, F ^[2]

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1. ORNL
2. Tulane University

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and is the simplest example of nuclear beta decay. It played a key role in the early Universe as it determined the ratio of neutrons to protons during the era of primordial light element nucleosynthesis. Neutron decay is physically related to important processes in solar physics and neutrino detection. The mean neutron lifetime has been the subject of more than 20 major experiments done, using a variety of methods, between 1950 and the present. The most precise recent measurements have stated accuracies approaching 0.1%, but are not in good agreement as they differ by as much as 5 sigma using quoted uncertainties. The history of neutron lifetime measurements is reviewed and the different methods used are described, giving important examples of each. The discrepancies and some systematic issues in the experiments that may be responsible are discussed, and it is shown by means of global averages that the neutron lifetime is likely to lie in the range of 880 884 s. Plans and prospects for future experiments are considered that will address these systematic issues and improve our knowledge of the neutron lifetime.

• Research Organization: Oak Ridge National Laboratory (ORNL); Spallation Neutron Source
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1037070
• Journal Information: Reviews of Modern Physics, Journal Name: Reviews of Modern Physics Journal Issue: 4 Vol. 83; ISSN RMPHAT; ISSN 0034-6861
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTINEUTRINOS
BETA DECAY
DECAY
LIFETIME
NEUTRINO DETECTION
NEUTRONS
NUCLEOSYNTHESIS
PHYSICS
PROTONS
UNIVERSE