scholarly journals Nucleon and Δ electromagnetic form factors

2015 ◽  
Vol 39 ◽  
pp. 1560089
Author(s):  
Erik Bartoš ◽  
Stanislav Dubnička ◽  
Anna-Zuzana Dubničková
Keyword(s):  
Form Factor ◽  
Magnetic Dipole ◽  
Transition Form Factor ◽  
Form Factors ◽  
Dipole Transition ◽  
Nucleon Resonance ◽  
Electromagnetic Form Factors ◽  
Analytic Model ◽  
Transition Form ◽  
Measured Ratio

The unitary and analytic model for nucleons works very well. The model for spin [Formula: see text] baryons can predict static parameters for [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. We prepared the scheme how to construct the model also for [Formula: see text] nucleon resonance. It was used to describe transition form factor [Formula: see text] and the experimentally measured ratio [Formula: see text] with the help of relations for magnetic dipole transition and charge quadrupole form factors.

INFRARED RENORMALON EFFECTS ON LIGHT MESONS ELECTROMAGNETIC TRANSITION FORM FACTOR FMγ*(Q2, ω)

2003 ◽  
Vol 18 (07) ◽  
pp. 1023-1050 ◽  
Author(s):  
YEGANA V. MAMEDOVA
Keyword(s):  
Form Factor ◽  
Perturbative Qcd ◽  
Transition Form Factor ◽  
Form Factors ◽  
Transition Form ◽  
Coupling Constant ◽  
Electromagnetic Transition ◽  
Qcd Factorization ◽  
Factorization Formula ◽  
Light Mesons

The light pseudoscalar π0, η and η′ mesons electromagnetic transition γ* + γ* → M form factors FMγ*(Q2,ω) are calculated, applying the perturbative QCD factorization formula and the frozen coupling constant approximation. In the computations the O(αS) order expression for FMγ*(Q2,ω) and the mesons' infrared renormalon corrected distribution amplitudes are used. In the case of the η and η′ mesons, the SUf(3) ordinary octet-singlet mixing scheme is utilized. Comparisons are made with the results obtained, employing the mesons' ordinary distribution amplitudes and with γ + γ* → M transition form factors.

scholarly journals PION FORM FACTORS AT INTERMEDIATE MOMENTUM TRANSFER IN A COVARIANT APPROACH

1996 ◽  
Vol 11 (04) ◽  
pp. 655-675 ◽  
Author(s):  
ADAM SZCZEPANIAK ◽  
ANTHONY G. WILLIAMS
Keyword(s):  
Wave Function ◽  
Form Factor ◽  
Momentum Transfer ◽  
Transition Form Factor ◽  
Form Factors ◽  
Transition Form ◽  
Gauge Invariant ◽  
Pion Wave Function ◽  
Covariant Gauge ◽  
Text Component

We study the pion electromagnetic and γ*+π0→γ transition form factors at intermediate momentum transfer. We calculate soft, nonperturbative corrections to the leading perturbative amplitudes which arise from the [Formula: see text] component of the pion wave function. We work in Minkowski space and use a Lorentz-covariant, gauge-invariant generalized perturbative integral representation for the [Formula: see text] amplitudes. For the transition form factor we find relative insensitivity to the detailed nonperturbative structure of the wave function for |q2|≳10 GeV 2, whereas considerable sensitivity is found for the electromagnetic form factor.

scholarly journals Meson transition form factor measurements with A2

2019 ◽  
Vol 199 ◽  
pp. 02013
Author(s):  
L. Heijkenskjöld
Keyword(s):  
Form Factor ◽  
Transition Form Factor ◽  
Form Factors ◽  
Precision Measurements ◽  
High Yield ◽  
Transition Form ◽  
Dalitz Decay ◽  
Decay Data ◽  
Electromagnetic Structure ◽  
Photon Interactions

Meson transition form factors (TFF) describe the electromagnetic structure of mesons and hence provide an important tool for the understanding of the meson-photon interactions. The A2 experiment at MAMI provides a high yield of light mesons produced in photo-induced reactions on protons, which makes the experiment ideal for precision measurements of meson TFFs via studies of meson decays. The A2 collaboration has recently published results of TFFs obtained from measurements of Dalitz decays of the π0 and η mesons as well as the ω → π0e+e− decay. For the study of the η′ Dalitz decay, data has been collected and is being analysed. As a ongoing endeavour, A2 is performing a dedicated measurement of the π0 TFF with statistics increased by several factors compared to the previous A2 result.

scholarly journals Hadron Structure from Lattice QCD

2006 ◽  
Vol 21 (04) ◽  
pp. 720-725 ◽  
Author(s):  
◽  
J. W. Negele ◽  
B. Bistrovic ◽  
R. G. Edwards ◽  
G. Fleming ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Transition Form Factor ◽  
Form Factors ◽  
Electromagnetic Form Factors ◽  
Transition Form ◽  
Hadron Structure ◽  
Interacting Particles ◽  
Axial Charge ◽  
Charge Structure ◽  
Quark Masses

The structure of neutrons, protons, and other strongly interacting particles is now being calculated in full, unquenched lattice QCD with quark masses entering the chiral regime. This talk describes selected examples, including the nucleon axial charge, structure functions, electromagnetic form factors, the origin of the nucleon spin, the transverse structure of the nucleon, and the nucleon to Delta transition form factor.

scholarly journals Measurement of the ϕ → π 0 e + e − transition form factor with the KLOE detector

2016 ◽  
Vol 757 ◽  
pp. 362-367 ◽  
Author(s):  
A. Anastasi ◽  
D. Babusci ◽  
G. Bencivenni ◽  
M. Berlowski ◽  
C. Bloise ◽  
...  
Keyword(s):  
Form Factor ◽  
Transition Form Factor ◽  
Transition Form

scholarly journals Electromagnetic transition form factors of baryons in a relativistic Faddeev approach

2018 ◽  
Vol 181 ◽  
pp. 01013 ◽  
Author(s):  
Reinhard Alkofer ◽  
Christian S. Fischer ◽  
Hèlios Sanchis-Alepuz
Keyword(s):  
Ground State ◽  
Bound States ◽  
Body Wave ◽  
Form Factors ◽  
Wave Functions ◽  
Electromagnetic Form Factors ◽  
Transition Form ◽  
Electromagnetic Transition ◽  
Three Body ◽  
Gluon Interaction

The covariant Faddeev approach which describes baryons as relativistic three-quark bound states and is based on the Dyson-Schwinger and Bethe-Salpeter equations of QCD is briefly reviewed. All elements, including especially the baryons’ three-body-wave-functions, the quark propagators and the dressed quark-photon vertex, are calculated from a well-established approximation for the quark-gluon interaction. Selected previous results of this approach for the spectrum and elastic electromagnetic form factors of ground-state baryons and resonances are reported. The main focus of this talk is a presentation and discussion of results from a recent investigation of the electromagnetic transition form factors between ground-state octet and decuplet baryons as well as the octet-only Σ0 to Λ transition.

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