Improved limits on scalar weak couplings

I point out that β-delayed proton spectroscopy is a powerful probe of possible scalar contributions to nuclear β decay, and use Schardt and Riisager’s data on the shape of the beta-delayed proton peaks from the superallowed decays of ${}_{}{}^{32}{}_{}{}^{}\mathrm{Ar}$ and ${}_{}{}^{33}{}_{}{}^{}\mathrm{Ar}$ to set improved upper limits on such couplings. Implications of these limits for leptoquark masses are mentioned.