Pion electroproduction measurements in the nucleon resonance region

Abstract

We report new pion electroproduction measurements in the $\Delta (1232)$ resonance, utilizing the SHMS - HMS magnetic spectrometers of Hall C at Jefferson Lab. The data focus on a region that exhibits a strong and rapidly changing interplay of the mesonic cloud and quark-gluon dynamics in the nucleon. The results are in reasonable agreement with models that employ pion cloud effects and chiral effective field theory calculations, but at the same time they suggest that an improvement is required to the theoretical calculations and provide valuable input that will allow their refinements. The data illustrate the potential of the magnetic spectrometers setup in Hall C towards the study the $\Delta (1232)$ resonance. These first reported results will be followed by a series of measurements in Hall C, that will expand the studies of the $\Delta (1232)$ resonance offering a high precision insight within a wide kinematic range from low to high momentum transfers.

References in corpus (40)

• A unitary isobar model for pion photo- and electroproduction on the proton up to 1 GeV
• Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction
• Effective theory of the Delta(1232) in Compton scattering off the nucleon
• Analysis of Pion Photoproduction Data
• Dynamical Study of the Delta Excitation in N(e,e' pi) Reactions
• Electroproduction of the Delta Resonance at High Momentum Transfer
• Pion cloud and the $Q^2-$dependence of ${\gamma }^{\ast }N\leftrightarrow \Delta$ transition form factors
• Determination of the E2/M1 Ratio in the γN \to Δ(1232) Transition from a Simultaneous Measurement of p(\vecγ,p)π^0 and p(\vecγ,π^+)n
• Search for Quadrupole Strength in the Electro-excitation of the Delta(1232)
• Investigation of the conjectured nucleon deformation at low momentum transfer
• Measurement of the N to Delta(1232) Transition at High Momentum Transfer by pi0 Electroproduction
• The N to Delta electromagnetic transition form factors from Lattice QCD
• Chiral Effective-Field Theory in the Delta(1232) Region: Pion Electroproduction on the Nucleon
• Measurement of the recoil polarization in the p (\vec e, e' \vec p) pi^0 reaction at the Δ(1232) resonance
• A chiral bag model approach to delta electroproduction
• Delta-baryon electromagnetic form factors in lattice QCD
• Pi0 photo- and electroproduction at threshold within a dynamical model
• Recoil Polarization for Delta Excitation in Pion Electroproduction
• Lowest Q^2 Measurement of the gamma*p -> Delta Reaction: Probing the Pionic Contribution
• Nucleon to Delta transition form factors with $N_F=2+1$ domain wall fermions
• Measurement of the Polarized Structure Function ${\sigma }_{L{T}^{\prime }}$ for $p(\vec{e},e^{\prime }{\pi }^{+})n$ in the $\Delta (1232)$ Resonance Region
• Chiral symmetry and the Delta-Nucleon transition form factors
• Signatures of chiral dynamics in the Nucleon to Delta transition
• E2/M1 Mixing Ratio of $\Delta \to N\gamma$ and Hyperon Resonance Radiative Decay
• Measurement of the beam-helicity asymmetry in the p(e_pol,e'p)pi_0 reaction at the energy of the Delta(1232) resonance
• Measurement of the LT-asymmetry in π^0 electroproduction at the energy of the Δ(1232) resonance
• Determination of quadrupole strengths in the gamma*p-->Delta(1232) transition at Q2= 0.20 (GeV/c)2
• Measurement of the Transverse-Longitudinal Cross Sections in the p (e,e'p)pi0 Reaction in the Delta Region
• The role of the pion cloud in electroproduction of the $\Delta$(1232)
• Probing hadron wave functions in Lattice QCD
• Measurements of the gamma*p->Delta Reaction At Low Q^2: Probing the Mesonic Contribution
• Recoil Polarization Measurements for Neutral Pion Electroproduction at Q^2=1 (GeV/c)^2 Near the Delta Resonance
• Deviation of the Nucleon Shape From Spherical Symmetry: Experimental Status
• Neutral Pion Electroproduction in the Resonance Region at High $Q^2$
• Ovrview: The Shape of Hadrons
• Electromagnetic form factors in the Hypercentral Constituent Quark Model
• Electroexcitation of the ${\Delta }^{+}(1232)$ at low momentum transfer
• Measurements of the γ* p --> Δ(1232) reaction at low Q2
• Virtual Compton Scattering measurements in the nucleon resonance region
• Measurement of the Partial Cross Sections s(TT), s(LT) and [s(T)+epsilon*s(L)] of the p(e,e' pi+)n Reaction in the Delta(1232) Resonance