$A_{\beta }[E_{\beta }]$ in ${}^{37}$K decay: new physics with opposite $\beta$ helicity

Abstract

By extending our analysis and simulations of our ${}^{37}$K $\beta$-decay data set to allow the $\beta$ asymmetry with respect to nuclear spin to vary with $\beta$ energy $E_{\beta }$, we have gained sensitivity to new physics that depends on a helicity factor for the $\beta$, $m_{\beta }/E_{\beta }$. In particular, we constrain Lorentz scalar and tensor quark-lepton interaction strengths at a sensitivity complementary to the similar Fierz interference term in neutron $\beta$ decay. Our result for that new physics is a Fierz interference term $b$ = 0.033 $\pm$ 0.084 (stat) $\pm$ 0.039 (syst), consistent with the standard model electroweak interaction value $b=0$. We consider presently achieved complementarity to $\beta$-decay and particle physics experiments, along with projectable technical improvements to our method.

Observable now labelled b throughout, pedagogy including equations fixed. Included combined Abeta, b, fT constraint on revised exclusion plot more carefully

References in corpus (9)

• Measurement of the Beta-Neutrino Correlation of Sodium-21 using Shakeoff Electrons
• New Precise Measurement of the Pion Weak Form Factors in the Pi+ -> e+ nu gamma Decay
• Precision measurements of the ${}^{60}$Co $\beta$-asymmetry parameter in search for tensor currents in weak interactions
• An $\text{ab initio}$ strategy for taming nuclear-structure dependence of $V_{ud}$ extractions: the ${}^{10}\mathrm{C}\to {}^{10}\mathrm{B}$ superallowed transition
• Search for new physics in the lepton plus missing transverse momentum final state in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Measurement of the $\beta$-asymmetry parameter of ${}^{67}$Cu in search for tensor type currents in the weak interaction
• Precision half-life measurement of the \boldmath${\beta }^{+}$ decay of \tsups{37}K
• Data-driven reevaluation of $ft$-values in superallowed $\beta$ decays
• Lineshape response of plastic scintillator to pair production of 4.44 MeV gamma's