English
Related papers

Related papers: Electromagnetic transition form factors of the Rop…

200 papers

The pion electromagnetic form factor is investigated by using the dispersion relation with the superconvergence condition, which was proposed to synthesize the vector meson dominance model and QCD. The absorptive part is given as an…

High Energy Physics - Phenomenology · Physics 2007-05-23 Keiji Watanabe , Hirohisa Ishikawa , Masami Nakagawa

Elastic form factors provide information about the low energy structure of composite particles.Recent double polarization coincidence experiments significantly improved our knowledge of proton and neutron form factors. Recoil polarization…

Nuclear Experiment · Physics 2007-05-23 H. Schmieden

Nucleon and pion electromagnetic form factors are evaluated in the spacelike region within a light-front constituent quark model, where eigenfunctions of a mass operator, reproducing a large set of hadron energy levels, are adopted and…

Nuclear Theory · Physics 2009-10-28 F. Cardarelli , E. Pace , G. Salme' , S. Simula

We present our calculations of the electromagnetic form factor of pions. We explore the properties of pion form factor at momentum transfer larger than previous studies by including more combinations of source and sink momenta and using…

High Energy Physics - Lattice · Physics 2010-12-13 Pai-hsien Jennifer Hsu , George T. Fleming

The nucleon is modeled, using light front dynamics, as a relativistic system of three bound constituent quarks emersed in a cloud of pions. The pionic cloud is important for understanding low-momentum transfer physics, especially the…

Nuclear Theory · Physics 2009-11-07 Gerald A. Miller

We investigate the possible modifications of the nucleons' electromagnetic form factors in the framework of a modified Skyrme model allowing for nucleon deformation and using realistic nuclear mass distributions. We show that such effects…

Nuclear Theory · Physics 2007-05-23 Ulughbek T. Yakhshiev , Ulf-G. Meißner , Andreas Wirzba

A model is developed for electromagnetic form factors of the charged and neutral K-mesons. The formalism is based on ChPT Lagrangians with vector mesons. The form factors, calculated without fitting parameters, are in a good agreement with…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. A. Ivashyn , A. Yu. Korchin

The central tenet of effective theory is that the details of short-distance physics will not have a significant impact on low-energy observables. Here we perform an analysis of electron-deuteron scattering at low momentum transfers which is…

Nuclear Theory · Physics 2009-04-17 D. R. Phillips , T. D. Cohen

We compute the electromagnetic form factors of the nucleon in quenched lattice QCD, using non-perturbatively improved Wilson fermions, and compare the results with phenomenology and chiral effective field theory.

High Energy Physics - Lattice · Physics 2010-04-06 M. Göckeler , T. R. Hemmert , R. Horsley , D. Pleiter , P. E. L. Rakow , A. Schäfer , G. Schierholz

We review the dispersion-theoretical analysis of the electromagnetic form factors of the nucleon. We emphasize in particular the role of unitarity and analyticity in the construction of the isoscalar and isovector spectral functions. We…

High Energy Physics - Phenomenology · Physics 2021-08-27 Yong-Hui Lin , Hans-Werner Hammer , Ulf-G. Meißner

For a relativistic system of two scalar particles, we find the Bethe-Salpeter amplitude in Minkowski space and use it to compute the electromagnetic form factor. The comparison with Euclidean space calculation shows that the Wick rotation…

High Energy Physics - Phenomenology · Physics 2010-04-21 J. Carbonell , V. A. Karmanov , M. Mangin-Brinet

We study the low energy expansion of the nucleon's electroweak form factors in the framework of an effective chiral Lagrangian including pions, nucleons and the $Delta (1232)$. We work to third order in the so-called small scale expansion…

High Energy Physics - Phenomenology · Physics 2009-10-31 Véronique Bernard , Harold W. Fearing , Thomas R. Hemmert , Ulf-G. Meißner

We perform an analysis of the form factors that rule the structure-dependent amplitude in the radiative pion decay. The resonance contributions to pion -> e nu_e gamma decays are computed through the proper construction of the vector and…

High Energy Physics - Phenomenology · Physics 2008-11-26 V. Mateu , J. Portoles

The electromagnetic form factors provide important insight into the internal structure of the nucleon and continue to be of major interest for experiment and phenomenology. For an intermediate range of momenta the form factors can be…

We briefly summarize the status with electromagnetic nucleon form factors, and give in this framework, arguments to study the angular dependence of the differential cross section and single-spin polarization phenomena (polarized target or…

High Energy Physics - Phenomenology · Physics 2008-10-24 Egle Tomasi-Gustafsson , Michail P. Rekalo

Dispersion relations allow for a coherent description of the nucleon electromagnetic form factors measured over a large range of momentum transfer, $Q^2 \simeq 0 \ldots 35$ GeV$^2$. Including constraints from unitarity and perturbative QCD,…

High Energy Physics - Phenomenology · Physics 2008-11-26 P. Mergell , Ulf-G. Meißner , D. Drechsel

The nucleon isovector electromagnetic form factors are calculated up to next-to-next-to-leading order by combining relativistic chiral perturbation theory (ChPT) of pion, nucleon, and $\Delta$(1232) with dispersion theory. We specifically…

High Energy Physics - Phenomenology · Physics 2023-12-18 Fernando Alvarado , Di An , Luis Alvarez-Ruso , Stefan Leupold

The pion electromagnetic form factor at spacelike momentum transfer is calculated in relativistic impulse approximation using the Covariant Spectator Theory. The same dressed quark mass function and the equation for the pion bound-state…

High Energy Physics - Phenomenology · Physics 2014-01-09 Elmar P. Biernat , Franz Gross , M. T. Peña , Alfred Stadler

I review the results of a recent dispersion--theoretical analysis of the nucleon electromagnetic form factors and comment on the strangeness form factors. The need for a better data basis at low, intermediate and large momentum transfer is…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ulf-G. Meißner

Point-form relativistic quantum mechanics is used to derive an expression for the electromagnetic form factor of a pseudoscalar meson for space-like momentum transfers. The elastic scattering of an electron by a confined quark-antiquark…

Nuclear Theory · Physics 2010-04-23 Elmar P. Biernat , Kajetan Fuchsberger , William H. Klink , Wolfgang Schweiger