Beam-Recoil Polarization Measurement of π[superscript 0] Electroproduction on the Proton in the Region of the Roper Resonance
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Alternative title
Beam-Recoil Polarization Measurement of π0 Electroproduction on the Proton in the Region of the Roper Resonance
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The helicity-dependent recoil proton polarizations P[superscript '][subscript x] and P[superscript ′][subscript z] as well as the helicity-independent component P[subscript y] have been measured in the p([→ over e],e[superscript ′][→ over p])π[superscript 0] reaction at four-momentum transfer Q[superscript 2]≃0.1 GeV[superscript 2], center-of-mass proton emission angle θ[superscript *][subscript 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[subscript 11](1440) by exploiting recoil polarimetry has allowed for the extraction of its scalar electroexcitation amplitude at an unprecedentedly low value of Q[superscript 2], establishing a powerful instrument for probing the interplay of quark and meson degrees of freedom in the nucleon.
Date issued
2017-07Department
Massachusetts Institute of Technology. Laboratory for Nuclear ScienceJournal
Physical Review Letters
Publisher
American Physical Society
Citation
Štajner, S. et al. “Beam-Recoil Polarization Measurement of π[superscript 0] Electroproduction on the Proton in the Region of the Roper Resonance.” Physical Review Letters 119.2 (2017): n. pag. © 2017 American Physical Society
Version: Final published version
ISSN
0031-9007
1079-7114