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Precision measurements of the {sup 60}Co {beta}-asymmetry parameter in search for tensor currents in weak interactions

Journal Article · · Physical Review. C, Nuclear Physics
; ; ; ; ; ; ; ; ; ; ; ; ;  [1];  [2];  [3]
  1. K. U. Leuven, Instituut voor Kern-en Stralingsfysica, Celestijnenlaan 200D, B-3001 Leuven (Belgium)
  2. Nuclear Physics Institute, ASCR, CZ-250 68 Rez (Czech Republic)
  3. Cyclotron Institute, Texas A and M University, College Station, Texas 77845 (United States)
The {beta}-asymmetry parameter A-tilde for the Gamow-Teller decay of {sup 60}Co was measured by polarizing the radioactive nuclei with the brute-force low-temperature nuclear-orientation method. The {sup 60}Co activity was cooled down to milliKelvin temperatures in a {sup 3}He-{sup 4}He dilution refrigerator in an external 13-T magnetic field. The {beta} particles were observed by a 500-{mu}m-thick Si PIN diode operating at a temperature of about 10 K in a magnetic field of 0.6 T. Extensive geant4 Monte Carlo simulations were performed to gain control over the systematic effects. Our result, A-tilde=-1.014(12){sub stat}(16){sub syst}, is in agreement with the standard-model value of -0.987(9), which includes recoil-order corrections that were addressed for the first time for this isotope. Further, it enables limits to be placed on possible tensor-type charged weak currents, as well as other physics beyond the standard model.
OSTI ID:
21499216
Journal Information:
Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 5 Vol. 82; ISSN 0556-2813; ISSN PRVCAN
Country of Publication:
United States
Language:
English