Baryon transition form factors at the pole

Abstract

Electromagnetic resonance properties are uniquely defined at the pole and do not depend on the separation of the resonance from background or the decay channel. Photon-nucleon branching ratios are nowadays often quoted at the pole, and we generalize the considerations to the case of virtual photons. We derive and compare relations for nucleon to baryon transition form factors both for the Breit-Wigner and the pole positions. Using the MAID2007 and SAID SM08 partial wave analyses of pion electroproduction data, we compare the $G_M$, $G_E$, and $G_C$ form factors for the $\Delta (1232)$ resonance excitation at the Breit-Wigner resonance and pole positions up to $Q^2=5$ GeV${}^2$. We also explore the $E/M$ and $S/M$ ratios as functions of $Q^2$. For pole and residue extraction, we apply the Laurent + Pietarinen method.

arXiv comment13 pages, 4 figures

References in corpus (50)

• Unitary Isobar Model - MAID2007
• Electromagnetic excitation of the Delta(1232)-resonance
• Properties of baryon resonances from a multichannel partial wave analysis
• Electroexcitation of nucleon resonances from CLAS data on single pion electroproduction
• Nucleon resonances within a dynamical coupled-channels model of pi N and gamma N reactions
• Electroexcitation of nucleon resonances
• Electroproduction of the Delta Resonance at High Momentum Transfer
• Analytic properties of the scattering amplitude and resonances parameters in a meson exchange model
• 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
• Electromagnetic Excitation of Nucleon Resonances
• Search for Quadrupole Strength in the Electro-excitation of the Delta(1232)
• Nucleon and $\Delta$ elastic and transition form factors
• Measurement of the N to Delta(1232) Transition at High Momentum Transfer by pi0 Electroproduction
• Eta photoproduction in a combined analysis of pion- and photon-induced reactions
• 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
• Photocouplings at the Pole from Pion Photoproduction
• A framework for the calculation of the $\Delta N{\gamma }^{\ast }$ transition form factors on the lattice
• A systematic study of longitudinal and transverse helicity amplidutes in the hypercentral Constituent Quark Model
• Recoil Polarization for Delta Excitation in Pion Electroproduction
• Dynamical coupled-channels analysis of 1H(e,e'pi)N reactions
• Elastic and transition form factors of the Δ(1232)
• Chiral Extrapolations and the Covariant Small Scale Expansion
• Nucleon to Delta transition form factors with $N_F=2+1$ domain wall fermions
• The role of the background in the extraction of resonance contributions from meson-baryon scattering
• Transition form factors of the N*(1535) as a dynamically generated resonance
• Relevance of complex branch points for partial wave analysis
• Signatures of chiral dynamics in the Nucleon to Delta transition
• Extraction of Electromagnetic Transition Form Factors for Nucleon Resonances within a Dynamical Coupled-Channels Model
• Timelike gamma* N -> Delta form factors and Delta Dalitz decay
• Measurement of the LT-asymmetry in π^0 electroproduction at the energy of the Δ(1232) resonance
• The role of the pion cloud in electroproduction of the $\Delta$(1232)
• Measurements of the gamma*p->Delta Reaction At Low Q^2: Probing the Mesonic Contribution
• Delta and Omega electromagnetic form factors in a three-body covariant Bethe-Salpeter approach
• Rôle of the pion electromagnetic form factor in the $\Delta (1232)\to {\gamma }^{\ast }N$ timelike transition
• Recoil Polarization Measurements for Neutral Pion Electroproduction at Q^2=1 (GeV/c)^2 Near the Delta Resonance
• Singularity structure of the pi N scattering amplitude in a meson-exchange model up to energies W < 2.0 GeV
• Pole positions and residues from pion photoproduction using the Laurent+Pietarinen expansion method
• Radiative decay of the Delta(1700)
• Poles of Karlsruhe-Helsinki KH80 and KA84 solutions extracted by using Laurent+Pietarinen method
• Baryon photo-decay amplitudes at the pole
• Determination of Delta resonance parameters from lattice QCD
• Helicity Amplitudes of the Lambda(1670) and two Lambda(1405) as dynamically generated resonances
• Effects of a spin-flavour dependent interaction on light-flavoured baryon helicity amplitudes
• High $Q^2$ behavior of the electromagnetic form factors in the relativistic hypercentral CQM
• Pole structure from energy-dependent and single-energy fits to $\pi N$ elastic scattering data
• Electroexcitation of the Delta(1232)3/2+ and Delta(1600)3/2+ in a light-front relativistic quark model
• Multichannel Anomaly of the Resonance Pole Parameters Resolved
• Generalization of the model-independent Laurent-Pietarinen single-channel pole-extraction formalism to multiple channels
• Configuration mixings and light-front relativistic quark model predictions for the electroexcitation of the Delta(1232)3/2+, N(1440)1/2+, and Delta(1600)3/2+

Cited by in corpus (11)

• Strong evidence for nucleon resonances near 1900\,MeV
• Jülich-Bonn-Washington Model for Pion Electroproduction Multipoles
• Towards the Minimal Spectrum of Excited Baryons
• Numerical calculation of the decay widths, the decay constants, and the decay energy spectra of the resonances of the delta-shell potential
• The MAID Legacy and Future
• Nucleon-to-Delta transition form factors in chiral effective field theory using the complex-mass scheme
• Two-photon exchange corrections to ${\gamma }^{\ast }N\Delta$ form factors for $Q^2\le 4$ (Gev/$c$)${}^2$
• Global Data-Driven Determination of Baryon Transition Form Factors
• Dispersive analysis of low energy ${\gamma }^{\ast }N\to \pi N$ process
• Laurent+Pietarinen Partial Wave Analysis
• Axial-vector nucleon-to-delta transition form factors using the complex-mass renormalization scheme