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A revised global fit of electroweak $ep$ and $\nu p$ elastic scattering data has been performed, with the goal of determining the strange quark contribution to the vector and axial-vector form factors of the nucleon in the momentum-transfer…

High Energy Physics - Phenomenology · Physics 2014-11-18 Stephen Pate , Dennis Trujillo

We analyze the nucleon matrix element of the strange quark vector current in a nucleon--model independent dispersive approach with input from the current world data set for the isoscalar electromagnetic form factors. The update of Jaffe's…

High Energy Physics - Phenomenology · Physics 2008-11-26 Hilmar Forkel

The total contribution of strange quarks to the intrinsic spin of the nucleon can be determined from a measurement of the strange-quark contribution to the nucleon's elastic axial form factor. We have studied the strangeness contribution to…

High Energy Physics - Experiment · Physics 2014-05-19 S. F. Pate , J. P. Schaub , D. P. Trujillo

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

Relativistic, kinematically complete phenomenological expressions for the dilepton decay rates of nucleon resonances with arbitrary spin and parity are derived in terms of the magnetic, electric, and Coulomb transition form factors. The…

Nuclear Theory · Physics 2011-08-17 M. I. Krivoruchenko , B. V. Martemyanov , Amand Faessler , C. Fuchs

The impulse approximation (one-body operator) in the n p --> d pi^0 reaction is reexamined with emphasis on the issues of reducibility and recoil corrections. An inconsistency when one pion exchange is included in the production operator is…

Nuclear Theory · Physics 2015-03-17 Daniel R. Bolton , Gerald A. Miller

The electromagnetic form factors of the nucleon are calculated at order $q^4$ in the relativistic formulation of baryon chiral perturbation theory. In order to obtain a consistent power counting for the renormalized diagrams we make use of…

Nuclear Theory · Physics 2009-11-10 Thomas Fuchs , Jambul Gegelia , Stefan Scherer

Due to the angular condition in the light-front dynamics (LFD), the extraction of the electromagnetic form factors for spin-1 particles can be uniquely determined taking into account implicitly non-valence and/or the zero-mode contributions…

High Energy Physics - Phenomenology · Physics 2018-05-23 J. P. B. C. de Melo , T. Frederico , Chueng -R. Ji

The momentum distributions of the constituent quarks inside the nucleon and the prominent electroproduced nucleon resonances are investigated in the two most sophisticated, available quark potential models, based respectively on the…

Nuclear Theory · Physics 2011-04-15 F. Cardarelli , E. Pace , G. Salme' , S. Simula

Extending a recent suggestion for hyperon form factors to the nucleon case, dispersion theory is used to relate the low-energy vector-isovector form factors of the nucleon to the pion vector form factor. The additionally required input,…

High Energy Physics - Phenomenology · Physics 2018-02-14 Stefan Leupold

With data collected in a dedicated energy scan from 2.3864 up to 3.0800 GeV, the BESIII collaboration provides the first complete energy-dependent measurements of the $\Lambda$ electromagnetic form factors in the time-like region. By…

High Energy Physics - Experiment · Physics 2026-01-13 The BESIII Collaboration

We have calculated the NLO corrections for the leading twist amplitude of the reaction $\gamma^*\gamma\to\pi\pi$ at large virtuality of the photon and at $W^2\ll Q^2$. With a simple model for the two-pion quark and gluon distribution…

High Energy Physics - Phenomenology · Physics 2008-11-26 N. Kivel , L. Mankiewicz , M. V. Polyakov

We present updated results for the nucleon axial charge and electromagnetic (EM) form factors, which include a significant increase in statistics for all ensembles (up to 4000 measurements), as well as the addition of ensembles with pion…

High Energy Physics - Lattice · Physics 2014-04-09 B. Jäger , T. D. Rae , S. Capitani , M. Della Morte , D. Djukanovic , G. von Hippel , B. Knippschild , H. B. Meyer , H. Wittig

We discuss questions related to the interpretation of unexpected results of measurements of the proton form factors ratio G_E/G_M in the polarization experiments done in JLab in the region of 0.5 < Q^2 < 8.5 GeV^2. For this purpose, in the…

Nuclear Theory · Physics 2013-02-05 M. V. Galynskii , E. A. Kuraev

Effects of the in-medium modifications of nucleon form factors on neutrino interaction in dense matter are presented by considering both the weak and electromagnetic interactions of neutrinos with the constituents of the matter. A…

Nuclear Theory · Physics 2020-01-08 Parada T. P. Hutauruk , Yongseok Oh , K. Tsushima

In this talk, we report results of our recent studies to delineate effects of the tensor force on the density dependence of nuclear symmetry energy within phenomenological models. The tensor force active in the isosinglet neutron-proton…

Nuclear Theory · Physics 2015-06-05 Chang Xu , Ang Li , Bao-An Li

The 16O(e,e'p) reaction in the quasi-elastic region has been studied in several experiments to determine spectroscopic factors, hence, the degree to which $^{16}$O looks like a closed shell. By varying the kinematics, experimentalists are…

Nuclear Theory · Physics 2016-08-03 J. Grineviciute , Dean Halderson

We study the effect of wave function orthogonality in the relativistic treatment of the nucleon removal reactions (gamma, p) and (e, e' p). The continuum wave function describing the outgoing nucleon is made orthogonal to the relevant bound…

Nuclear Theory · Physics 2009-10-31 J. I. Johansson , H. S. Sherif

Distorted-wave methods are used to remove the effects of one- and two-pion exchange up to order Q^3 from the empirical 1P1 phase shift. The one divergence that arises can be renormalised using an order-Q^2 counterterm which is provided by…

Nuclear Theory · Physics 2011-02-28 K. L. Ipson , K. Helmke , M. C. Birse

In Poincar\'e-covariant continuum treatments of the three valence-quark bound-state problem, the force behind dynamical chiral symmetry breaking also generates nonpointlike, interacting diquark correlations in the nucleon and its…

Nuclear Theory · Physics 2016-11-09 Jorge Segovia , Craig D. Roberts