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M. T. Burkey, G. Savard, A. T. Gallant, N. D. Scielzo, J. A. Clark, T. Hirsh, L. Varriano, G. H. Sargsyan, Kristina D. Launey, M. Brodeur, D. P. Burdette, E. Heckmaier, K. Joerres, J. Klimeš, K. Kolos, A. Laminack, K. G. Leach, A. F. Levand, B. Longfellow, Bernhard Maaß, S. T. Marley, G. Morgan, Peter Mueller, R. Orford, S. Padgett, A. Pérez Galván, Jacob R. Pierce, D. Ray, R. E. Segel, K. Siegl, K. S. Sharma, B. S. Wang
Abstract
The electroweak interaction in the standard model is described by a pure vector-axial-vector structure, though any Lorentz-invariant component could contribute. In this Letter, we present the most precise measurement of tensor currents in the low-energy regime by examining the $\ensuremath{\beta}\text{\ensuremath{-}}\overline{\ensuremath{\nu}}$ correlation of trapped $^{8}\mathrm{Li}$ ions with the Beta-decay Paul Trap. We find ${a}_{\ensuremath{\beta}\ensuremath{\nu}}=\ensuremath{-}0.3325\ifmmode\pm\else\textpm\fi{}0.001{3}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}0.001{9}_{\mathrm{syst}}$ at $1\ensuremath{\sigma}$ for the case of coupling to right-handed neutrinos (${C}_{T}=\ensuremath{-}{C}_{T}^{\ensuremath{'}}$), which is consistent with the standard model prediction.