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Title: Precision Measurement Of The Neutron's Beta Asymmetry Using Ultra-Cold Neutrons

Abstract

A measurement of A{beta}, the correlation between the electron momentum and neutron (n) spin (the beta asymmetry) in n beta-decay, together with the n lifetime, provides a method for extracting fundamental parameters for the charged-current weak interaction of the nucleon. In particular when combined with decay measurements, one can extract the Vud element of the CKM matrix, a critical element in CKM unitarity tests. By using a new SD2 super-thermal source at LANSCE, large fluxes of UCN (ultra-cold neutrons) are expected for the UCNA project. These UCN will be 100% polarized using a 7 T magnetic field, and directed into the {beta} spectrometer. This approach, together with an expected large reduction in backgrounds, will result in an order of magnitude reduction in the critical systematic corrections associated with current n {beta}-asymmetry measurements. This paper will give an overview of the UCNA A{beta} measurement as well as an update on the status of the experiment.

Authors:
 [1];  [2];  [3];  [4]
  1. Los Alamos National Lab., P.O. Box 1663, Los Alamos, NM 87545 (United States)
  2. North Carolina State University Raleigh, NC 27695 (United States)
  3. University of Washington, Department of Physics, Box 351560 Seattle, WA 98195 (United States)
  4. California Institute of Technology, Kellogg Radiation Lab, Pasadena, CA 91125 (United States)
Publication Date:
OSTI Identifier:
20875834
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 842; Journal Issue: 1; Conference: 17. international conference on particles and nuclei, Santa Fe, NM (United States), 23-30 Oct 2005; Other Information: DOI: 10.1063/1.2220389; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACCURACY; ASYMMETRY; BETA DECAY; CHARGED CURRENTS; CORRECTIONS; CORRELATIONS; ELECTRIC MOMENTS; ELECTRON SPECTROMETERS; ELECTRONS; KOBAYASHI-MASKAWA MATRIX; LIFETIME; MAGNETIC FIELDS; SPIN; ULTRACOLD NEUTRONS; UNITARITY; WEAK INTERACTIONS

Citation Formats

Makela, M, Back, H O, Melconian, D, and Plaster, B. Precision Measurement Of The Neutron's Beta Asymmetry Using Ultra-Cold Neutrons. United States: N. p., 2006. Web. doi:10.1063/1.2220389.
Makela, M, Back, H O, Melconian, D, & Plaster, B. Precision Measurement Of The Neutron's Beta Asymmetry Using Ultra-Cold Neutrons. United States. doi:10.1063/1.2220389.
Makela, M, Back, H O, Melconian, D, and Plaster, B. Tue . "Precision Measurement Of The Neutron's Beta Asymmetry Using Ultra-Cold Neutrons". United States. doi:10.1063/1.2220389.
@article{osti_20875834,
title = {Precision Measurement Of The Neutron's Beta Asymmetry Using Ultra-Cold Neutrons},
author = {Makela, M and Back, H O and Melconian, D and Plaster, B},
abstractNote = {A measurement of A{beta}, the correlation between the electron momentum and neutron (n) spin (the beta asymmetry) in n beta-decay, together with the n lifetime, provides a method for extracting fundamental parameters for the charged-current weak interaction of the nucleon. In particular when combined with decay measurements, one can extract the Vud element of the CKM matrix, a critical element in CKM unitarity tests. By using a new SD2 super-thermal source at LANSCE, large fluxes of UCN (ultra-cold neutrons) are expected for the UCNA project. These UCN will be 100% polarized using a 7 T magnetic field, and directed into the {beta} spectrometer. This approach, together with an expected large reduction in backgrounds, will result in an order of magnitude reduction in the critical systematic corrections associated with current n {beta}-asymmetry measurements. This paper will give an overview of the UCNA A{beta} measurement as well as an update on the status of the experiment.},
doi = {10.1063/1.2220389},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 842,
place = {United States},
year = {2006},
month = {7}
}