相关论文: Factorization, Power Corrections, and the Pion For…
We investigate the next-to-next-to-leading order (NNLO) QCD radiative corrections to the pion electromagnetic form factor with large momentum transfer. We explicitly verify the validity of the collinear factorization to two-loop order for…
The electromagnetic pion form factor, $F_\pi(q^2)$, is calculated for spacelike-$q^2$ in impulse approximation using a confining quark propagator, $S$, and a dressed quark-photon vertex, $\Gamma_\mu$, obtained from realistic,…
The pion electromagnetic form factor with leading and next-to-leading twist corrections are studied in the framework of pQCD approach. We find that, at small momentum transfer regions, Sudakov effects cannot provide a strong enough…
Motivated by recent measurements at J-Lab, the pion electromagnetic form-factor is investigated with quenched domain wall fermions and a renormalization group improved gauge action called DBW2. We see that quark mass dependence of the…
We comment on the results of a complete leading-twist next-to-leading order QCD analysis of the spacelike pion electromagnetic form factor at large-momentum transfer Q. For the asymptotic distribution amplitude, we have examined the…
The leptonic radiative decay $B \to \gamma l\nu$ is of great importance in the determination of $B$ meson wave functions, and evaluating the form factors $ F_{V,A}$ are the essential problem on the study of this channel. We computed…
We have reexamined the elastic pion form factor over a broad range of momentum transfers with the mass evolution from current quark to constituent quark being taken into account. We have also studied the effect of Sudakov form factors, of…
We present preliminary results from the first calculation of the pion electromagnetic form factor at physical light quark masses. This form factor parameterises the deviations from the behaviour of a point-like particle when a photon hits…
Recent measurement of the $\gamma\gamma^\ast$ form factor of the neutral pion in the high $Q^2$ region disagrees with {\em a priori} predictions of QCD-based calculations. We comment on existing explanations, and analyze a possibility that…
We propose a perturbative evaluation for the next-to-leading-order (NLO) $O(1/Q^4)$ power correction to the photon-pion transition form factor. The effects of the NLO power correction are analyzed.
We study the electromagnetic form factor of the pion and kaons at low-energies with the use of Chiral Perturbation Theory. The analysis is performed within the three flavour framework and at next-to-next-to-leading order. We explain…
Recent work on the theme of power corrections in perturbative QCD is briefly reviewed, with an emphasis on event shapes in e+ e- annihilation. The factorization of soft gluon effects is the main tool: it leads to resummation, and thus…
We perform a perturbative QCD analysis of the quark transverse momentum effect on the pion-photon transition form factors $F_{\pi \gamma}$ and $F_{\pi \gamma^*}$ in the standard light-cone formalism, with two phenomenological models of…
We present a lattice calculation of the electromagnetic form factor of the pion obtained using the tree-level Symanzik improved gauge action with two flavors of dynamical twisted Wilson quarks. The simulated pion masses range approximately…
This review contains an overview over recent results for the electromagnetic iso-vector form factor of the pion obtained in lattice QCD with dynamical fermions. Particular attention is given to the extrapolation to the physical point and an…
We calculate next-to-leading-order (NLO) correction to the pion electromagnetic form factor at leading twist in the $k_T$ factorization theorem. Partons off-shell by $k_T^2$ are considered in both quark diagrams and effective diagrams for…
We present an investigation of the electromagnetic pion form factor, $F_\pi(Q^2)$, at small values of the four-momentum transfer $Q^2$ ($\lesssim 0.25$ GeV$^2$), based on the gauge configurations generated by European Twisted Mass…
An analysis of all available data (CELLO, CLEO, \babar) in the range $[1\div 40]$ GeV$^2$ for the pion-photon transition form factor in terms of light-cone sum rules with next-to-leading-order accuracy is discussed, including twist-four…
Electromagnetic form factors serve to explore the intrinsic structure of nucleons and their strangeness partners. For the decay $\Sigma^0\to\Lambda e^+e^-$, due to limited phase space, the effects caused by the Sigma-to-Lambda transition…
The electromagnetic form factor of the pion in the space-like region, and at finite temperature, $F_{\pi}(Q^{2},T)$, is obtained from a QCD Finite Energy Sum Rule. The form factor decreases with increasing T, and vanishes at some critical…