Rôle of the pion electromagnetic form factor in the $\Delta (1232)\to {\gamma }^{\ast }N$ timelike transition

Abstract

The $\Delta (1232)\to {\gamma }^{\ast }N$ magnetic dipole form factor ($G_M^{\ast }$) is described here within a new covariant model that combines the valence quark core together with the pion cloud contributions. The pion cloud term is parameterized by two terms: one connected to the pion electromagnetic form factor, the other to the photon interaction with intermediate baryon states. The model can be used in studies of pp and heavy ion collisions. In the timelike region this new model improves the results obtained with a constant form factor model fixed at its value at zero momentum transfer. At the same time, and in contrast to the Iachello model, this new model predicts a peak for the transition form factor at the expected position, i.e. at the $\rho$ mass pole. We calculate the decay of the $\Delta \to \gamma N$ transition, the Dalitz decay ($\Delta \to e^{+}{e}^{-}N$), and the $\Delta$ mass distribution function. The impact of the model on dilepton spectra in pp collisions is also discussed.

11 pages, 10 figures

References in corpus (10)

• Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor
• A pure S-wave covariant model for the nucleon
• Dilepton production in proton-induced reactions at SIS energies with the GiBUU transport model
• D-state effects in the electromagnetic N-Delta transition
• A relativistic quark model for the Omega- electromagnetic form factors
• A Covariant model for the nucleon and the $\Delta$
• Dynamical coupled-channels analysis of 1H(e,e'pi)N reactions
• Nucleon to Delta transition form factors with $N_F=2+1$ domain wall fermions
• Timelike gamma* N -> Delta form factors and Delta Dalitz decay
• ${\gamma }^{\ast }N\to N(1710)$ transition at high momentum transfer

Cited by in corpus (26)

• Baryons as relativistic three-quark bound states
• Light dark matter in neutrino beams: production modelling and scattering signatures at MiniBooNE, T2K and SHiP
• Dilepton production and resonance properties within a new hadronic transport approach in the context of the GSI-HADES experimental data
• Electromagnetic Transition Form Factors of Baryon Resonances
• Hyperon electromagnetic timelike elastic form factors at large $q^2$
• Dilepton Radiation from Strongly Interacting Systems
• Axial form factors of the octet baryons in a covariant quark model
• $\Delta$(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES
• ${\gamma }^{\ast }N\to N^{\ast }(1520)$ form factors in the timelike regime
• Production and electromagnetic decay of hyperons: a feasibility study with HADES as a Phase-0 experiment at FAIR
• Semirelativistic approximation to the ${\gamma }^{\ast }N\to N(1520)$ and ${\gamma }^{\ast }N\to N(1535)$ transition form factors
• Valence quark contributions for the ${\gamma }^{\ast }N\to N(1440)$ form factors from Light-Front holography
• Improved empirical parametrizations of the ${\gamma }^{\ast }N\to \Delta (1232)$ and ${\gamma }^{\ast }N\to N(1520)$ helicity amplitudes and the Siegert's theorem
• $N^{\ast }$ Form Factors based on a Covariant Quark Model
• Electromagnetic form factors of the ${\Omega }^{-}$ baryon in the spacelike and timelike regions
• Baryon transition form factors at the pole
• Covariant model for the Dalitz decay of the $N(1535)$ resonance
• Analysis of the exclusive final state npe${}^{+}$e${}^{-}$ in quasi-free np reaction
• Dilepton production in microscopic transport theory with in-medium $\rho$-meson spectral function
• A covariant model for the decuplet to octet Dalitz decays
• Role of baryon resonances in the ${\pi }^{-}p\to n{e}^{+}{e}^{-}$ reaction within an effective-Lagrangian model
• Weak interaction axial form factors of the octet baryons in nuclear medium
• Meson cloud contributions to the Dalitz decays of decuplet to octet baryons
• Electroweak form factors of baryons in dense nuclear matter
• Quark model calculations of transition form factors at high photon virtualities
• A Relativistic Model for the Electromagnetic Structure of Baryons from the 3rd Resonance Region