Kavli Affiliate: A. C. Davis | Summary:We report measurements of the parity-conserving beam-normal single-spin elastic scattering asymmetries $B_n$ on $^12$C and $^27$Al, obtained with an electron beam polarized transverse to its momentum direction. These measurements add an additional kinematic point to a series of previous measurements of $B_n$ on $^12$C and provide a first measurement on $^27$Al. The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energy of 1.158 GeV. The average lab scattering angle for both targets was 7.7 degrees, and the average $Q^2$ for both targets was 0.02437 GeV$^2$ (Q=0.1561 GeV). The asymmetries are $B_n$ = -10.68 $pm$ 0.90 stat) $pm$ 0.57 (syst) ppm for $^12$C and $B_n$ = -12.16 $pm$ 0.58 (stat) $pm$ 0.62 (syst) ppm for $^27$Al. The results are consistent with theoretical predictions, and are compared to existing data. When scaled by Z/A, the Q-dependence of all the far-forward angle (theta < 10 degrees) data from $^1$H to $^27$Al can be described by the same slope out to $Q approx 0.35$ GeV. Larger-angle data from other experiments in the same Q range are consistent with a slope about twice as steep. | Search Query: arXiv Query: search_query=au:”Davis A. C.”&id_list=&start=0&max_results=10Read More