Related papers: Disconnected Electromagnetic Form Factors
We compute the structure-dependent axial and vector form factors for the radiative leptonic decays $D_s\to \ell\nu_\ell\gamma$, where $\ell$ is a charged lepton, as functions of the energy of the photon in the rest frame of the $D_s$ meson.…
We discuss methods for the calculation of disconnected diagrams and their application to various form factors of the nucleon. In particular, we present preliminary results for the strange contribution to the scalar and axial form factors,…
We briefly report on results about the electromagnetic form factors of the nucleon obtained with different models and then we concentrate our attention on recent results obtained with the hypercentral constituent quark model (hCQM).
We discuss techniques for evaluating sea quark contributions to hadronic form factors on the lattice and apply these to an exploratory calculation of the strange electromagnetic, axial, and scalar form factors of the nucleon. We employ the…
Elastic electromagnetic form factors of nucleons are investigated both for the time-like and the space-like momentums under the condition that the QCD constraints are satisfied asymptotically. The unsubtracted dispersion relation with the…
Predictions for the electromagnetic form factors of the Lambda$, Sigma and Xi hyperons are presented. The numerical calculations are performed within the framework of the fully relativistic constituent-quark model developed by the Bonn…
The extraction of the magnetic form factor of the nucleon at zero momentum transfer is usually performed by adopting a parametrization for its momentum dependence and fitting the results obtained at finite momenta. We present a position…
The strange contribution to the electric and magnetic form factors of the nucleon is determined at a range of discrete values of $Q^2$ up to $1.4$ GeV$^2$. This is done by combining recent lattice QCD results for the electromagnetic form…
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…
Form factors of the nucleon have been extracted from experiment with high precision. However, lattice calculations have failed so far to reproduce the observed dependence of form factors on the momentum transfer. We have embarked on a…
We present lattice QCD calculations of nucleon electromagnetic form factors using pion masses $m_\pi$ = 149, 202, and 254 MeV and an action with clover-improved Wilson quarks coupled to smeared gauge fields, as used by the…
The nucleon electromagnetic form factors are calculated in light cone QCD sum rules framework using the most general form of the nucleon interpolating current. Using two forms of the distribution amplitudes (DA's), predictions for the form…
The QCDSF/UKQCD collaboration has an ongoing program to calculate nucleon matrix elements with two flavours of dynamical O(a) improved Wilson fermions. Here we present recent results on the electromagnetic form factors, the quark momentum…
Results on the electromagnetic form factors of the nucleon using twisted mass fermion configurations are presented. These include a gauge field ensemble simulated with two degenerate light quarks yielding a pion mass of around 130 MeV, as…
The charged and neutral kaon form factors are calculated as a phenomenological application of the QCD Dyson-Schwinger equations. The results are compared with the pion form factor calculated in the same framework and yield…
We present a simple covariant constituent diquark-quark model for the nucleon. The nucleon is assumed to be composed of a scalar diquark and a quark which interact via a quark exchange. Starting from the Bethe-Salpeter equation, the…
Effective demagnetizing factors that connect the sample magnetic moment with the applied magnetic field are calculated numerically for perfectly diamagnetic samples of various non-ellipsoidal shapes. The procedure is based on calculating…
We compute the electromagnetic form factors of the proton and neutron using lattice QCD. We employ $N_\mathrm{f}$=2+1+1 twisted mass clover-improved fermions with quark masses tuned to their physical values. Three ensembles with lattice…
The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated…
The role of the strange quarks on the low-energy interactions of the proton can be probed through the strange electromagnetic form factors. Knowledge of these form factors provides essential input for parity-violating processes and…