Precision Measurement of the β Asymmetry in Spin-Polarized K37 Decay
| Autor: | S. Smale, R. S. Behling, Daniel Ashery, Melissa Anholm, M. Mehlman, Inon Cohen, Gerald Gwinner, Dan Melconian, Praveen Shidling, I. Craiciu, A. Gorelov, J. C. McNeil, B. Fenker, K. Olchanski, C. L. Warner, John Behr |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
010308 nuclear & particles physics media_common.quotation_subject Physics beyond the Standard Model Nuclear Theory General Physics and Astronomy 01 natural sciences Asymmetry Standard Model 0103 physical sciences High Energy Physics::Experiment Beta (velocity) Neutron Atomic physics Nuclear Experiment 010306 general physics Spin (physics) media_common |
| Zdroj: | Physical Review Letters. 120 |
| ISSN: | 1079-7114 0031-9007 |
| Popis: | Using Triumf's neutral atom trap, Trinat, for nuclear $\ensuremath{\beta}$ decay, we have measured the $\ensuremath{\beta}$ asymmetry with respect to the initial nuclear spin in $^{37}\mathrm{K}$ to be ${A}_{\ensuremath{\beta}}=\ensuremath{-}0.5707{(13)}_{\mathrm{syst}}{(13)}_{\mathrm{stat}}{(5)}_{\mathrm{pol}}$, a 0.3% measurement. This is the best relative accuracy of any $\ensuremath{\beta}$-asymmetry measurement in a nucleus or the neutron, and is in agreement with the standard model prediction $\ensuremath{-}0.5706(7)$. We compare constraints on physics beyond the standard model with other $\ensuremath{\beta}$-decay measurements, and improve the value of ${V}_{\mathrm{ud}}$ measured in this mirror nucleus by a factor of 4. |
| Databáze: | OpenAIRE |
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