Measurement of the helicity asymmetry E for the reaction γ p → π 0 p : The CBELSA/TAPS Collaboration.
M GottschallF AfzalA V AnisovichD BayadilovR BeckM BichowK Th BrinkmannV CredeM DieterleF DietzH DutzH EberhardtD ElsnerR EwaldK Fornet-PonseSt FriedrichF FrommbergerA GridnevM GrünerE GutzCh HammannJ HannappelJ HartmannW HillertPh HoffmeisterCh HonischT JudeS KammerH KalinowskyI KeshelashviliP KlassenF KleinE KlemptK KoopB KruscheM KubeM LangI LopatinP MahlbergK MakonyiV MetagW MeyerJ MüllerJ MüllersM NanovaV NikonovR NovotnyD PiontekG ReicherzT RostomyanA SarantsevCh SchmidtH SchmiedenT SeifenV SokhoyanK SpiekerA ThielU ThomaM UrbanH van PeeD WaltherCh WendelD WerthmüllerU WiednerA WilsonA WinnebeckL WitthauerY WunderlichPublished in: The European physical journal. A, Hadrons and nuclei (2021)
A measurement of the double-polarization observable E for the reaction γ p → π 0 p is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C 4 H 9 OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from E γ = 600 to 2310 MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses.