Corrections for the polarization-dependent efficiency and new neutron-proton analyzing power data at 7.6 MeV

Abstract

We present new corrections for the polarization-dependent efficiency (PDE), which introduces a false asymmetry into measurements of $n\text{\ensuremath{-}}p$ analyzing power ${A}_{y}(\ensuremath{\theta})$ caused by double scattering in the neutron side detectors. To accomplish this, we created a new database of $^{12}\mathrm{C}$$(\mathrm{nP\vec},n)$ ${A}_{y}(\ensuremath{\theta})$ by using a combination of fits to data, phase-shift analysis, and $R$-matrix analysis. Our recorrection for PDE of previously reported $n\text{\ensuremath{-}}p$ ${A}_{y}(\ensuremath{\theta})$ data at 7.6 and 12.0 MeV and new data at 7.6 MeV indicate that we have achieved a superior representation of $^{12}\mathrm{C}$$(\mathrm{nP\vec},n)$. Our results continue to suggest a possible charge dependence of the pion-nucleon coupling constant.