EPJ Web of Conferences (Jan 2019)
The Nab experiment: A precision measurement of unpolarized neutron beta decay
- Fry J.,
- Alarcon R.,
- Baeßler S.,
- Balascuta S.,
- Palos L. Barrón,
- Bailey T.,
- Bass K.,
- Birge N.,
- Blose A.,
- Borissenko D.,
- Bowman J.D.,
- Broussard L.J.,
- Bryant A.T.,
- Byrne J.,
- Calarco J.R.,
- Caylor J.,
- Chang K.,
- Chupp T.,
- Cianciolo T.V.,
- Crawford C.,
- Ding X.,
- Doyle M.,
- Fan W.,
- Farrar W.,
- Fomin N.,
- Frlež E.,
- Gericke M.T.,
- Gervais M.,
- Glück F.,
- Greene G.L.,
- Grzywacz R.K.,
- Gudkov V.,
- Hamblen J.,
- Hayes C.,
- Hendrus C.,
- Ito T.,
- Jezghani A.,
- Li H.,
- Makela M.,
- Macsai N.,
- Mammei J.,
- Mammei R.,
- Martinez M.,
- Matthews D.G.,
- McCrea M.,
- McGaughey P.,
- McLaughlin C.D.,
- Mueller P.,
- Petten D. van,
- Penttilä S.I.,
- Perryman D.E.,
- Picker R.,
- Pierce J.,
- Počanić D.,
- Qian Y.,
- Ramsey J.,
- Randall G.,
- Riley G.,
- Rykaczewski K.P.,
- Salas-Bacci A.,
- Samiei S.,
- Scott E.M.,
- Shelton T.,
- Sjue S.K.,
- Smith A.,
- Smith E.,
- Stevens E.,
- Wexler J.,
- Whitehead R.,
- Wilburn W.S.,
- Young A.,
- Zeck B.
Affiliations
- Fry J.
- Department of Physics, University of Virginia
- Alarcon R.
- Department of Physics, Arizona State University
- Baeßler S.
- Department of Chemistry and Physics, University of Tennessee at Chattanooga
- Balascuta S.
- Department of Physics, Arizona State University
- Palos L. Barrón
- Universidad Nacional Autónoma de México
- Bailey T.
- Department of Physics, North Carolina State University
- Bass K.
- Department of Physics and Astronomy, University of Tennessee
- Birge N.
- Department of Physics and Astronomy, University of Tennessee
- Blose A.
- Department of Physics and Astronomy, University of Kentucky
- Borissenko D.
- Department of Physics, University of Virginia
- Bowman J.D.
- Physics Division, Oak Ridge National Laboratory
- Broussard L.J.
- Physics Division, Oak Ridge National Laboratory
- Bryant A.T.
- Department of Physics, University of Virginia
- Byrne J.
- Department of Physics and Astronomy, University of Sussex
- Calarco J.R.
- Caylor J.
- Department of Physics and Astronomy, University of Tennessee
- Chang K.
- Department of Physics, University of Virginia
- Chupp T.
- University of Michigan
- Cianciolo T.V.
- Physics Division, Oak Ridge National Laboratory
- Crawford C.
- Department of Physics and Astronomy, University of Kentucky
- Ding X.
- Department of Physics, University of Virginia
- Doyle M.
- Department of Physics, University of Virginia
- Fan W.
- Department of Physics, University of Virginia
- Farrar W.
- Department of Physics, University of Virginia
- Fomin N.
- Department of Physics and Astronomy, University of Tennessee
- Frlež E.
- Department of Physics, University of Virginia
- Gericke M.T.
- Department of Physics, University of Manitoba
- Gervais M.
- Department of Physics and Astronomy, University of Kentucky
- Glück F.
- KIT, Universität Karlsruhe (TH)
- Greene G.L.
- Grzywacz R.K.
- Department of Physics and Astronomy, University of Tennessee
- Gudkov V.
- Department of Physics and Astronomy, University of South Carolina
- Hamblen J.
- Department of Chemistry and Physics, University of Tennessee at Chattanooga
- Hayes C.
- Department of Physics, North Carolina State University
- Hendrus C.
- University of Michigan
- Ito T.
- Los Alamos National Laboratory
- Jezghani A.
- Department of Physics and Astronomy, University of Kentucky
- Li H.
- Department of Physics, University of Virginia
- Makela M.
- Los Alamos National Laboratory
- Macsai N.
- Department of Physics, University of Manitoba
- Mammei J.
- Department of Physics, University of Manitoba
- Mammei R.
- Department of Physics, University of Winnipeg
- Martinez M.
- Department of Physics, Arizona State University
- Matthews D.G.
- Department of Physics and Astronomy, University of Kentucky
- McCrea M.
- Department of Physics and Astronomy, University of Kentucky
- McGaughey P.
- Los Alamos National Laboratory
- McLaughlin C.D.
- Department of Physics, University of Virginia
- Mueller P.
- Physics Division, Oak Ridge National Laboratory
- Petten D. van
- Department of Physics, University of Virginia
- Penttilä S.I.
- Physics Division, Oak Ridge National Laboratory
- Perryman D.E.
- Department of Physics and Astronomy, University of Tennessee
- Picker R.
- TRIUMF
- Pierce J.
- Physics Division, Oak Ridge National Laboratory
- Počanić D.
- Department of Physics, University of Virginia
- Qian Y.
- Department of Physics, University of Virginia
- Ramsey J.
- Physics Division, Oak Ridge National Laboratory
- Randall G.
- Department of Physics, Arizona State University
- Riley G.
- Department of Physics and Astronomy, University of Tennessee
- Rykaczewski K.P.
- Physics Division, Oak Ridge National Laboratory
- Salas-Bacci A.
- Department of Physics, University of Virginia
- Samiei S.
- Department of Physics, University of Virginia
- Scott E.M.
- Department of Physics and Astronomy, University of Tennessee
- Shelton T.
- Department of Physics and Astronomy, University of Kentucky
- Sjue S.K.
- Los Alamos National Laboratory
- Smith A.
- Department of Physics, University of Virginia
- Smith E.
- Los Alamos National Laboratory
- Stevens E.
- Department of Physics, University of Virginia
- Wexler J.
- Department of Physics, North Carolina State University
- Whitehead R.
- Department of Physics and Astronomy, University of Tennessee
- Wilburn W.S.
- Los Alamos National Laboratory
- Young A.
- Department of Physics, North Carolina State University
- Zeck B.
- Department of Physics, North Carolina State University
- DOI
- https://doi.org/10.1051/epjconf/201921904002
- Journal volume & issue
-
Vol. 219
p. 04002
Abstract
Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, λ = gA/gV, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter a with a precision of δa/a = 10−3 and the Fierz interference term b to δb = 3 × 10−3 in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio λ with a precision of δλ/λ = 0.03% that will allow an evaluation of Vud and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.
