Constraints on axial two-body currents from solar neutrino data

Abstract

We briefly review recent calculations of neutrino-deuteron cross sections within the effective field theory and traditional potential model approaches. We summarize recent efforts to determine the counter term describing axial two-body currents, ${L}_{1A}$, in the effective field theory approach. We determine the counterterm directly from the solar neutrino data and find several, slightly different, ranges of ${L}_{1A}$ under different sets of assumptions. Our most conservative fit value with the largest uncertainty is ${L}_{1A}={4.5}_{\ensuremath{-}12}^{+18}{\phantom{\rule{0.3em}{0ex}}\text{fm}}^{3}$. We show that the contribution of the uncertainty of ${L}_{1A}$ to the analysis and interpretation of the solar neutrino data measured at the Sudbury Neutrino Observatory is significantly less than the uncertainty coming from the lack of having a better knowledge of ${\ensuremath{\theta}}_{13}$.