%AAndroic, D.%AArmstrong, D.S.%AAsaturyan, A%ABartlett, K.%ABeaufait, J.%ABeminiwattha, R.S.%ABenesch, J.%ABenmokhtar, F.%ABirchall, J.%ACarlini, R.D.%ACornejo, J.C.%ADusa, S.%ADalton, M.%ADavis, C.A.%ADowd, J.%ADunne, J.A.%ADutta, D.%ADuvall, W.S.%AElaasar, M.%AFalk, W.R.%AFinn, J.%AForest, T.%AGal, C.%AGaskell, D.%AGericke, M.T.W.%AGray, V.M.%AGrimm, K.%AGuo, F.%AHoskins, J.%AJones, D.%AJones, M.%AJones, R.%AKargiantoulakis, M.%AKing, P.M.%AKorkmaz, E.%AKowalski, S.%ALeacock, J.%ALeckey, J.P.%ALee, A.R.%ALee, J.H.%ALee, L.%AMacEwan, S.%AMack, D. Magee%AMahurin, R.%AMammei, J.%AMartin, J.%AMcHugh, M.J.%AMeekins, D.%AMei, J.%AMesick, K.E.%AMichaels, R.%AMicherdzinska, A.%AMkrtchyan, A.%AMkrtchyan, H.%AMorgan, N.%ANarayan, A.%ANdukum, L.Z.%ANelyubin, V.%ANuruzzaman, N.%Avan Oers, W.T.H.%AOwen, V.F.%APage, S.A.%APan, J.%APaschke, K.D.%APhillips, S.K.%APitt, M.L.%ARadloff, R.W.%ARajotte, J.F.%ARamsay, W.D.%ARoche, J.%ASawatzky, B.%ASeva, T.%AShabestari, M.H.%ASilwal, R.%ASimicevic, N.%ASmith, G.R.%ASolvignon, P.%ASpayde, D.T.%ASubedi, A.%ASubedi, R.%ASuleiman, R.%ATadevosyan, V.%ATobias, W.A.%ATvaskis, V.%AWaidyawansa, B.%AWang, P.%AWells, S.P.%AWood, S.A.%AYang, S.%AZang, P.%AZhamkochyan, S.%BJournal Name: Physical review letters; Journal Volume: 125; Journal Issue: 11 %D2020%I %JJournal Name: Physical review letters; Journal Volume: 125; Journal Issue: 11 %K %MOSTI ID: 10276390 %PMedium: X %TPrecision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering %XA beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θlab=7.9° and a mean energy of 1.149 GeV. The asymmetry result is Bn=−5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θlab→0) where they should be most reliable. %0Journal Article