0000000001301209

AUTHOR

S. Stiliaris

showing 9 related works from this author

Lowest- Q2 measurement of the γp → Δ reaction: Probing the pionic contribution

2006

To determine nonspherical angular momentum amplitudes in hadrons at long ranges (low Q^2), data were taken for the p(\vec{e},e'p)\pi^0 reaction in the Delta region at Q^2=0.060 (GeV/c)^2 utilizing the magnetic spectrometers of the A1 Collaboration at MAMI. The results for the dominant transition magnetic dipole amplitude and the quadrupole to dipole ratios at W=1232 MeV are: M_{1+}^{3/2} = (40.33 +/- 0.63_{stat+syst} +/- 0.61_{model}) (10^{-3}/m_{\pi^+}),Re(E_{1+}^{3/2}/M_{1+}^{3/2}) = (-2.28 +/- 0.29_{stat+syst} +/- 0.20_{model})%, and Re(S_{1+}^{3/2}/M_{1+}^{3/2}) = (-4.81 +/- 0.27_{stat+syst} +/- 0.26_{model})%. These disagree with predictions of constituent quark models but are in reaso…

PhysicsDipoleAngular momentumNuclear and High Energy PhysicsPionHadronQuadrupoleLattice (group)Constituent quarkHigh Energy Physics::ExperimentAtomic physicsNuclear ExperimentMagnetic dipoleThe European Physical Journal A
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Determination of quadrupole strengths in the γ∗p→Δ(1232) transition at Q2=0.20(GeV/c)2

2007

Abstract We report new precise p ( e → , e ′ p ) π 0 measurements at the peak of the Δ + ( 1232 ) resonance at Q 2 = 0.20 ( GeV / c ) 2 performed at the Mainz Microtron (MAMI). The new data are sensitive to both the electric (E2) and the Coulomb (C2) quadrupole amplitudes of the γ ∗ N → Δ transition. They yield precise quadrupole to dipole amplitude ratios: CMR = ( − 5.09 ± 0.28 stat + sys ± 0.30 model ) % and EMR = ( − 1.96 ± 0.68 stat + sys ± 0.41 model ) % for M 1 + 3 / 2 = ( 39.57 ± 0.75 stat + sys ± 0.40 model ) ( 10 −3 / m π + ) . The new results are in disagreement with Constituent Quark Model predictions and in qualitative agreement with models that account for mesonic contributions…

Nuclear physicsPhysicsNuclear and High Energy PhysicsDipoleAmplitudeQuark modelHadronQuadrupoleCoulombConstituent quarkHigh Energy Physics::ExperimentNuclear ExperimentMicrotronPhysics Letters B
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"Table 1" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."

2006

Measured value of SIG(C=T) + EPS*SIG(C=L) as a function of the pion angle relative to the virtual photon direction.

ComputingMilieux_THECOMPUTINGPROFESSIONElectron productionNuclear TheoryIntegrated Cross SectionComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONCross SectionSIGInformationSystems_MODELSANDPRINCIPLES7.950E-017.950E-01E- P --> E- PI0 PExclusiveInformationSystems_MISCELLANEOUS1.221ComputingMethodologies_COMPUTERGRAPHICSComputer Science::Cryptography and Security
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"Table 5" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."

2006

Unpolarized cross sections as a function of the azimuthal pion angle relative to the virtual photon direction from which the extracted results were taken (to be published).

Electron production7.950E-017.950E-01Integrated Cross SectionE- P --> E- PI0 PExclusiveCross SectionNuclear ExperimentSIG1.221
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"Table 3" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."

2006

Measured value of SIG(C=LT) as a function of the pion angle relative to thevirtual photon direction.

Electron productionNuclear Theory7.950E-017.950E-01Integrated Cross SectionE- P --> E- PI0 PExclusiveCross SectionNuclear ExperimentSIG1.221Computer Science::Cryptography and Security
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"Table 4" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."

2006

Measured value of SIG(C=LTP) as a function of the pion angle relative to the virtual photon direction.

Quantitative Biology::Neurons and CognitionElectron productionQuantitative Biology::Molecular NetworksNuclear TheoryIntegrated Cross SectionComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONCross SectionSIG7.950E-017.950E-01E- P --> E- PI0 PExclusiveNuclear Experiment1.221ComputingMethodologies_COMPUTERGRAPHICSComputer Science::Cryptography and Security
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"Table 2" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."

2006

Measured value of SIG(C=TT) as a function of the pion angle relative to thevirtual photon direction.

Electron productionNuclear Theory7.950E-017.950E-01Integrated Cross SectionE- P --> E- PI0 PExclusiveCross SectionNuclear ExperimentSIG1.221Computer Science::Cryptography and Security
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"Table 7" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."

2006

Unpolarized cross sections as a function of the azimuthal pion angle relative to the virtual photon direction from which the extracted results were taken (to be published).

Electron production7.950E-017.950E-01Integrated Cross SectionE- P --> E- PI0 PExclusiveCross SectionNuclear ExperimentSIG1.221
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"Table 6" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."

2006

Unpolarized cross sections as a function of the azimuthal pion angle relative to the virtual photon direction from which the extracted results were taken (to be published).

Electron production7.950E-017.950E-01Integrated Cross SectionE- P --> E- PI0 PExclusiveCross SectionNuclear ExperimentSIG1.221
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