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The electromagnetic and gravitational form factors of the nucleon are studied simultaneously using a covariant quark-diquark approach, and the pion cloud effect on the form factors is explicitly discussed. In this study, the electromagnetic…

High Energy Physics - Phenomenology · Physics 2025-08-14 Jiaqi Wang , Dongyan Fu , Yubing Dong

By using the AdS/CFT correspondence, we investigate various form factors between nucleons and mesons in a nuclear medium. In order to describe a nuclear medium holographically, we take into account the thermal charged AdS geometry with an…

High Energy Physics - Theory · Physics 2018-02-14 Chanyong Park , Jung Hun Lee

We study the axial-vector form factor of the nucleons at constant and homogenous isospin chemical potential using holographic QCD. Nucleon mass splitting in such isospin medium is taken into account. According to AdS/CFT correspondence, the…

High Energy Physics - Phenomenology · Physics 2022-05-31 Ibrahim Atayev , Shahin Mamedov

The covariant spectator formalism is used to model the nucleon and the $\Delta$(1232) as a system of three constituent quarks with their own electromagnetic structure. The definition of the ``fixed-axis'' polarization states for the diquark…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. Ramalho , M. T. Pena , Franz Gross

The phase structure of a two-fluid bosonic system is investigated. The proton-neutron interacting boson model (IBM-2) posesses a rich phase structure involving three control parameters and multiple order parameters. The surfaces of quantum…

Nuclear Theory · Physics 2007-05-23 M. A. Caprio , F. Iachello

We reanalyze the world data on the electromagnetic form factors of the nucleon. The calculations are performed in the framework of an algebraic model of the nucleon combined with vector meson dominance.

Nuclear Theory · Physics 2017-11-03 R. Bijker , A. Leviatan

$C_5^A(Q^2)$ axial form factor is extracted from the ANL neutrino-deuteron scattering data with deuteron structure effects taken into consideration. The best fit of the $C_5^A(Q^2)$ axial form factor is obtained assuming dipole…

High Energy Physics - Phenomenology · Physics 2010-01-15 Krzysztof M. Graczyk , D. Kielczewska , Jan T. Sobczyk

Form factors are Lorentz invariant functions describing the internal structure of a system. In particular, they encode how physical properties like, e.g., charge, energy, momentum, and pressure are spatially distributed. While nucleon…

High Energy Physics - Phenomenology · Physics 2024-02-02 Cédric Lorcé

We discuss the electromagnetic form factors, axial form factors, and structure functions of a bound nucleon in the quark-meson coupling (QMC) model. Free space nucleon form factors are calculated using the improved cloudy bag model (ICBM).…

Nuclear Theory · Physics 2007-05-23 K. Tsushima , D. H. Lu , W. Melnitchouk , K. Saito , A. W. Thomas

The electromagnetic form factors of nucleons are calculated using an AdS/QCD model by considering a Dirac field coupled to a vector field in the 5-dimensional AdS space. We also calculate a gravitational or energy-momentum form factor by…

High Energy Physics - Phenomenology · Physics 2009-06-30 Zainul Abidin , Carl E. Carlson

We present results on the electromagnetic and axial nucleon form factors using two degenerate flavors of twisted mass fermions on lattices of spatial size 2.1 fm and 2.7 fm and a lattice spacing of about 0.09 fm. We consider pion masses in…

High Energy Physics - Lattice · Physics 2010-02-05 C. Alexandrou , T. Korzec , G. Koutsou , R. Baron , P. Guichon , M. Brinet , J. Carbonell , P. -A. Harraud , K. Jansen

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…

High Energy Physics - Phenomenology · Physics 2016-02-12 G. Ramalho , M. T Pena , J. Weil , H. van Hees , U. Mosel

We compute the electromagnetic form factors of the nucleon in the Poincare-covariant Faddeev framework based on the Dyson-Schwinger equations of QCD. The general expression for a baryon's electromagnetic current in terms of three…

High Energy Physics - Phenomenology · Physics 2011-08-08 Gernot Eichmann

We present high statistics results for the structure of the nucleon from a mixed-action calculation using 2+1 flavors of asqtad sea and domain wall valence fermions. We perform extrapolations of our data based on different chiral effective…

We calculate the electromagnetic form factors of a bound proton. The Chiral Quark-Soliton model provides the quark and antiquark substructure of the proton, which is embedded in nuclear matter. This procedure yields significant…

Nuclear Theory · Physics 2008-11-26 Jason R. Smith , Gerald A. Miller

We present results on the nucleon axial form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length $L=2.1$ fm and $L=2.8$ fm. Cut-off…

High Energy Physics - Lattice · Physics 2015-03-17 C. Alexandrou , M. Brinet , J. Carbonell , M. Constantinou , P. A. Harraud , P. Guichon , K. Jansen , T. Korzec , M. Papinutto

We present a detailed analysis of nucleon electromagnetic and axial form factors in a holographic soft-wall model. This approach is based on an action which describes hadrons with broken conformal invariance and incorporates confinement…

High Energy Physics - Phenomenology · Physics 2012-08-23 Thomas Gutsche , Valery E. Lyubovitskij , Ivan Schmidt , Alfredo Vega

We treat baryons as bound states of scalar or axialvector diquarks and a constituent quark which interact through quark exchange. This description results as an approximation to the relativistic Faddeev equation for three quarks which…

Nuclear Theory · Physics 2009-10-31 M. Oettel , S. Ahlig , R. Alkofer , C. Fischer

The mass spectra of nucleon resonances with spin 1/2, 3/2, and 5/2 are systematically studied in the constituent quark model with meson-quark coupling, which is inspired by the spontaneous breaking of chiral symmetry of QCD. The meson-quark…

Nuclear Theory · Physics 2009-10-30 H. Kowata , M. Arima , K. Masutani

The electromagnetic form factors of the proton and the neutron in the timelike region are reviewed. In view of the forthcoming experimental projects devoted to investigate these observables, we present the current status of the field and we…

High Energy Physics - Experiment · Physics 2012-10-18 Achim Denig , Giovanni Salme`