Related papers: Excited state systematics in extracting nucleon el…
I give an overview on experimental studies of the spectrum and the structure of the excited states of the nucleon and what we can learn about their internal structure. One focus is on the efforts to obtain a more complete picture of the…
We present lattice-QCD results on the nucleon isovector axial, scalar and tensor charges, the isovector electromagnetic Dirac and Pauli form factors, and the connected parts of the isoscalar charges. The calculations have been done using…
We present results on the isovector and isoscalar nucleon axial form factors including disconnected contributions,using an ensemble of $N_f =2$ twisted mass clover- improved Wilson fermions simulated with approximately the physical value of…
According to the composite fermion theory, the interacting electron system at filling factor $\nu$ is equivalent to the non-interacting composite fermion system at $\nu^*=\nu/(1-2m\nu)$, which in turn is related to the non-interacting…
We present selected results obtained by RQCD from simulations of $N_f=2+1$ flavours of non-perturbatively $\mathcal{O}(a)$ improved Wilson fermions, employing open boundary conditions in time. The ensembles were created within the CLS…
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…
Variational analysis techniques in lattice QCD are powerful tools that give access to the excited state spectrum of QCD. At zero momentum, these techniques are well established and can cleanly isolate energy eigenstates of either positive…
We obtain the electromagnetic form factors of the nucleon, in the space-like region, using three-point function Finite Energy QCD Sum Rules. The QCD calculation is performed to leading order in perturbation theory in the chiral limit, and…
We present the strange electromagnetic form factors of the nucleon using lattice QCD with $N_f=2+1+1$ twisted mass clover-improved fermions and quark masses tuned to their physical values. Using four ensembles with lattice spacings of…
We employ a novel method to analyze Euclidean correlation functions entering the calculation of hadron energies in lattice QCD. The method is based on the sampling of all possible solutions allowed by the spectral decomposition of the…
We present the strange electromagnetic form factors of the nucleon using lattice QCD simulations with degenerate light, a strange, and a charm quark in the sea with masses tuned to their physical values. For the first time, the strange…
Extended vector meson dominance model, that allows to describe the electromagnetic form factors of nucleons obeying the asymptotic quark counting rule prescriptions and contains the minimal number of free parameters, is presented. We get a…
Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the…
It would be very useful to find a way of reducing excited-state effects in lattice QCD calculations of nucleon structure that has a low computational cost. We explore the use of hybrid interpolators, which contain a nontrivial gluonic…
We present high statistics ($\mathcal{O}(2\times 10^5)$ measurements) preliminary results on (i) the isovector charges, $g^{u-d}_{A,S,T}$, and form factors, $G^{u-d}_E(Q^2)$, $G^{u-d}_M(Q^2)$, $G^{u-d}_A(Q^2)$, $\widetilde G^{u-d}_P(Q^2)$,…
A group theoretical derivation of a relation between the N --> Delta charge quadrupole transition and neutron charge form factors is presented.
The nucleon-pion-state contribution to QCD two- and three-point functions used in the calculation of the axial form factors of the nucleon are studied in chiral perturbation theory. For physically small quark masses the nucleon-pion states…
The electromagnetic form factors of the nucleon are calculated in an extended chiral constituent-quark model where the effective interaction is described by the exchange of pseudoscalar, vector, and scalar mesons. Two-body current-density…
Quenched QCD hadron spectrum is calculated with Wilson's quark action at $\beta=5.85$ and 6.0 on a $24^3 \times 54$ lattice. We discuss the problem of whether we have extracted the mass of the ground state at these $\beta$'s without…
The Fat-Link Irrelevant Clover (FLIC) fermion action provides a new form of nonperturbative O(a) improvement and allows efficient access to the light quark-mass regime. FLIC fermions enable the construction of the nonperturbatively…