$N\mathrm{\text{−}}\Delta (1232)$ axial form factors from weak pion production

The $N\Delta$ axial form factors are determined from neutrino induced pion production ANL and BNL data by using a theoretical model that accounts both for background mechanisms and deuteron effects. We find violations of the off-diagonal Goldberger-Treiman relation at the level of $2\sigma$ which might have an impact in background calculations for T2K and MiniBooNE low energy neutrino oscillation precision experiments.

Figure 1

Comparison of the ANL $d\sigma /d{q}^2$ differential (left panel) and ANL and BNL total (right panel) cross-section data with fit IV theoretical results. Theoretical 68% confidence level bands are also displayed. Data in both plots include a systematic error (20% for ANL and 10% for BNL data) added in quadrature to the statistical ones. In the left panel, both data and results include a cut $W<1.4\mathrm{GeV}$.