6533b872fe1ef96bd12d2eef
RESEARCH PRODUCT
Beam-Recoil Polarization Measurement of π0 Electroproduction on the Proton in the Region of the Roper Resonance
J. MüllerU. MüllerL. CorreaS. KegelJ. PochodzallaB. S. SchlimmePatrick AchenbachConcettina SfientiS. ŠTajnerAnselm EsserT. BeranekM. MihovilovičJan C. BernauerL. TiatorI. YaronM. SchothR. BöhmH. FonvieilleA. WeberF. SchulzA. G. DenigD. BosnarM. O. DistlerY. KohlMichaela ThielL. NungesserS. ŠIrcaIvica FriščićJ. BeričičA. TyukinJ.m. FriedrichHarald Merkelsubject
QuarkRoper resonanceMesonpseudoscalar meson: production[PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph]Nuclear TheoryGeneral Physics and Astronomy[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]01 natural sciencesNuclear physicsRecoil0103 physical sciencesp: recoilInvariant masselectron: beamProton emissionnumerical calculations010306 general physicsNuclear ExperimentMonte Carlohydrogen: targetPhysicspolarizationN(1440)010308 nuclear & particles physicsbeam: currenthelicityAmplitudekinematicsdifferential cross sectionpi0: electroproductionBeam-Recoil Polarization MeasurementNucleondescription
The helicity-dependent recoil proton polarizations P_{x}^{'} and P_{z}^{'} as well as the helicity-independent component P_{y} have been measured in the p(e[over →],e^{'}p[over →])π^{0} reaction at four-momentum transfer Q^{2}≃0.1 GeV^{2}, center-of-mass proton emission angle θ_{p}^{*}≃90°, and invariant mass W≃1440 MeV. This first precise measurement of double-polarization observables in the energy domain of the Roper resonance P_{11}(1440) by exploiting recoil polarimetry has allowed for the extraction of its scalar electroexcitation amplitude at an unprecedentedly low value of Q^{2}, establishing a powerful instrument for probing the interplay of quark and meson degrees of freedom in the nucleon.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2017-01-01 |