Final results for the neutron β-asymmetry parameter A0 from the UCNA experiment

The UCNA experiment was designed to measure the neutron β-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A0.

[1]  Jr.,et al.  New result for the neutron β -asymmetry parameter A 0 from UCNA , 2017, 1712.00884.

[2]  C. Y. Liu,et al.  Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment , 2017, 1710.05182.

[3]  Zhehui Wang,et al.  Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source. , 2012, The Review of scientific instruments.

[4]  R. Vogelaar,et al.  Precision measurement of the neutron β-decay asymmetry , 2012, 1210.7048.

[5]  A. Holley,et al.  A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment. , 2012, The Review of scientific instruments.

[6]  M. Deissenroth,et al.  Determination of the weak axial vector coupling λ = gA/gV from a measurement of the β-asymmetry parameter A in neutron beta decay. , 2012, Physical review letters.

[7]  M. Mendenhall.  Measurement of the Neutron Beta Decay Asymmetry using Ultracold Neutrons , 2011 .

[8]  R. Vogelaar,et al.  Determination of the axial-vector weak coupling constant with ultracold neutrons. , 2010, Physical review letters.

[9]  S. Lamoreaux,et al.  First measurement of the neutron beta asymmetry with ultracold neutrons. , 2008, Physical review letters.

[10]  R. Carr,et al.  A solenoidal electron spectrometer for a precision measurement of the neutron β-asymmetry with ultracold neutrons , 2008, 0806.2097.

[11]  G. Rybka,et al.  A multiwire proportional chamber for precision studies of neutron β decay angular correlations , 2004, physics/0702085.

[12]  O. Zimmer,et al.  Is the unitarity of the quark-mixing CKM matrix violated in neutron beta-decay? , 2002, Physical review letters.

[13]  C. Zhang,et al.  Sharpening low-energy, standard-model tests via correlation coefficients in neutron beta decay. , 2000, Physical review letters.

[14]  B. Yerozolimsky,et al.  Corrigendum: Corrected value of the beta-emission asymmetry in the decay of polarized neutrons measured in 1990 , 1997 .

[15]  K. Schreckenbach,et al.  The measurement of the beta asymmetry in the decay of polarized neutrons , 1997 .

[16]  Alan D. Martin,et al.  Review of Particle Physics , 2000, Physical Review D.

[17]  Tóth,et al.  Order- alpha radiative corrections for semileptonic decays of polarized baryons. , 1992, Physical review. D, Particles and fields.

[18]  Freedman,et al.  Beta-decay asymmetry of the neutron and gA/gV. , 1986, Physical review letters.

[19]  D. Wilkinson.  Analysis of neutron -decay , 1982 .

[20]  B. Holstein.  Recoil effects in allowed beta decay: The elementary particle approach , 1974 .

[21]  J. Jackson,et al.  Possible Tests of Time Reversal Invariance in Beta Decay , 1957 .

[22]  Michael A. Brown.  Determination of the Neutron Beta-Decay Asymmetry Parameter A Using Polarized Ultracold Neutrons , 2018 .

[23]  R. T. Shann.  Electromagnetic effects in the decay of polarized neutrons , 1971 .