相关论文: Timelike and spacelike hadron form factors, Fock s…
New possibilities of high precision measurements of hadron form factors in annihilation and scattering reactions over an unexplored kinematical region suggest a compared analysis, in view of a global description of the nucleon structure.
QCD gives definite predictions for hadron electromagnetic form factors in space-like and time-like momentum transfer regions, such as the quark counting rules, the hypothesis of hadron helicity conservation, and the relations between…
We obtain the electromagnetic form factors, the axial form factor, and the parton distribution functions of the proton from the eigenstates of a light-front effective Hamiltonian in the leading Fock representation suitable for low-momentum…
The latest BABAR results on the proton and kaon timelike form factors (FF) are presented. The special emphasize is made on comparison of the spacelike and timelike FFs and the rise of the proton FF near threshold. The behavior of the cross…
We perform a nonperturbative lattice calculation of the complex phase and modulus of the pion form factor in the timelike momentum region using the finite-volume technique. We use two ensembles of 2+1-flavor overlap fermion at pion masses…
We calculate the transition form factor between vector and pseudoscalar quarkonia in both the timelike and the spacelike region using light-front dynamics. We investigate the frame dependence of the form factors for heavy quarkonia with…
Form factors of the proton, pion, and kaon for large timelike momentum transfers have recently been measured with precision. The results and future prospects are discussed.
A microscopic model of the electromagnetic form factor of the nucleon is developed in a hadronic framework, including pions, nucleons and the Delta-resonance explicitly. The space like on-shell form factors are reproduced and predictions…
We study the electromagnetic form factors of the nucleon in a collective model of baryons. In an algebraic approach to hadron structure, we derive closed expressions for both elastic and transition form factors, and consequently for the…
We review recent results on hadron form factors and nucleon generalized parton distibutions obtained with dynamical lattice QCD simulations. We discuss lattice artifacts and open questions, and present the connection of lattice results to…
We investigate space- and time-like form factors for $\omega\to\pi\gamma^*$ and $K^*\to K\gamma^*$ decays using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum…
The analogy between quantum chemistry and light-front quantum field theory, first noted by Kenneth G. Wilson, serves as motivation to develop light-front quantum simulation of quantum field theory. We demonstrate how calculations of hadron…
Lattice simulations of hadronic structure are now reaching a level where they are able to not only complement, but also provide guidance to current and forthcoming experimental programmes at, e.g. Jefferson Lab, COMPASS/CERN and FAIR/GSI.…
Some form factors of ground-state hadrons with spin might show a zero crossing at spacelike momenta of electron-hadron scattering. In the timelike region of hadron-antihadron production by electron-positron collisions the form factors…
With a special intention of clarifying the underlying spin contents of the nucleon, we investigate the generalized form factors of the nucleon, which are defined as the $n$-th $x$-moments of the generalized parton distribution functions,…
We present a formula that allows one to calculate the pion form factor in the timelike region 2mpi <= sqrt{s} <= 4mpi in lattice QCD. The form factor quantifies the contribution of two-pion states to the vacuum polarization. It must be…
The light-front approach is applied to calculate the electromagnetic current for quark-antiquark bound states for the pion. The pion electromagnetic form factor is obtnaide from the "+" and "-" components of the electromagnetic current in…
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…
Interaction with external gravitational field is introduced into a nonlocal quark model using the equivalence principle. This allows to define the energy-momentum tensor in flat space and evaluate its hadronic matrix element with external…
There has been considerable progress in the study of the electromagnetic form factors of baryons in the timelike region, through electron-positron scattering reactions ($e^+ e^- \to B \bar B$), in the last two decades. Timelike experiments…