6533b862fe1ef96bd12c6bb8

RESEARCH PRODUCT

Measurement of the Beam-Helicity Asymmetry in thep(e→,e′p)π0Reaction at the Energy of theΔ(1232)Resonance

M. KahrauI. EwaldD. BaumannA. WagnerU. MüllerJ.m. FriedrichD. ElsnerThomas WalcherM. DingG. RosnerJ. BermuthM. PotokarM. O. DistlerFrank KleinK. W. KrygierA. LiesenfeldM. WeisP. BartschP. MerleA. SüleR. BöhmS. HedickeL. TiatorDamir BosnarS.s. KamalovS. GrözingerDieter DrechselTh. PospischilKlemen BohincP. JenneweinMichael SeimetzR. NeuhausenH. SchmiedenJ.m. FriedrichHarald Merkel

subject

PhysicsParticle physicsmedia_common.quotation_subjectGeneral Physics and AstronomyResonanceHelicityAsymmetryCoincidenceNuclear physicsPionNuclear ExperimentMicrotronBeam (structure)Energy (signal processing)media_common

description

In a p((e) over right arrow, e' p)pi(0) out-of-plane coincidence experiment at the three-spectrometer setup of the Mainz Microtron MAMI, the beam-helicity asymmetry has been precisely measured around the energy of the Delta(1232) resonance and Q(2) = 0.2(GeV/c)(2). The results are in disagreement with three up-to-date model calculations. This is interpreted as a lack of understanding of the nonresonant background, which in dynamical models is related to the pion cloud.

yearjournalcountryeditionlanguage
2002-03-26Physical Review Letters
https://doi.org/10.1103/physrevlett.88.142001