Mary Silliman's War.

First Determination of the 27Al Neutron Distribution Radius from a Parity-Violating Electron Scattering Measurement

“…Any residual transverse components to the beam polarization will cause a parity-conserving azimuthal variation in the asymmetry, which coupled with imperfections in the azimuthal symmetry of the detectors may lead to a false asymmetry. This was measured using transversely polarized beam [16] and scaled to the measured azimuthal variation in the present data, leading to a correction A T = −3.4 ± 8.8 ppb [14].…”

“…Helicity-correlated variations in the beam position and energy also required a correction A reg = 0.4 ± 1.4 ppb. This was determined with a linear regression method [3,14], to correct the effects of natural beam-motion using helicity-correlated differences measured with different beam-position monitors.…”

“…Non-linearity effects in the main detector PMTs and BCMs used for asymmetry normalization were quantified in bench-top tests. The correction for this effect was A L = −2.0 ± 7.0 ppb [14,15].…”

“…Background contributions from pions, neutrals, and the beamline were negligible, and are discussed in [14]. The neutron distribution radius R n was determined using a many-models correlation method first employed by the PREX collaboration [21].…”