Related papers: Meson loop effects on the pion electromagnetic for…
By reanalysing transverse momentum dependence in the perturbative calculation of pion form factor an improved expression of pion form factor which takes into account the transverse momentum dependenc in hard scattering amplitude and…
Through an extended kinetic model, we study the nonlinear generation of quasi-static magnetic fields by high-frequency fields in a plasma, taking into account the effects of the electron spin. It is found that although the largest part of…
We calculate the leading quantum corrections to the meson form factors of nonrelativistic kinks, at momentum transfer much higher than the meson mass. We consider general scalar theories which need not be integrable. Our approach is much…
At the energies of present and future electron accelerators designed to study the structure of hadrons, there is a regime where hard pion electroproduction proceeds by a perturbatively calculable process in QCD. The process is not the…
NNLO QCD corrections for the pion electromagnetic form factor at large momentum transfer have been recently performed in [Phys. Rev. Lett. 132, 201901 (2024); Phys. Rev. Lett. 134, 221901 (2025)], revealing that the NLO and NNLO…
Form factors of nucleons and mesons with timelike momentum transfers are discussed. New experimental results for protons, pions, and kaons at large momentum transfers are presented, and the inadequacy of existing theoretical ideas about…
We investigate electromagnetic effects in the framework of chiral perturbation theory. Using a completely independent method, we confirm Urech's results for the divergences of the one--loop functional in the electromagnetic sector. We…
The anapole form factor of the nucleon is calculated in chiral perturbation theory in leading order. To this order, the form factor originates from the pion cloud, and is proportional to the non-derivative parity-violating pion-nucleon…
An addtional intrinsic form factors of pion and kaons have been studied.
We report on the calculation by the MILC Collaboration of the electromagnetic effects on kaon and pion masses. These masses are computed in QCD with dynamical (asqtad staggered) quarks plus quenched photons at three lattice spacings varying…
In this talk, we introduce an effective chiral action, derived from the instanton QCD vacuum configuration, in order to study the modification of mesonic properties in medium. We present our recent theoretical results on the electromagnetic…
The correction of the higher-order process for the photon-pion-pion vertex is calculated by the field theoretical method of the pion-nucleon system. The non-perturbative term of the pseudovector coupling interaction is included to examine…
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…
We evaluate the pion mass in finite volume to two loops within Chiral Perturbation Theory. The results are compared with a recently proposed extension of the asymptotic formula of Luscher. We find that contributions, which were neglected in…
We present a preliminary non-perturbative lattice calculation of the form factors entering the processes $K\to \ell\,\nu_\ell\,\ell'^+\,\ell'^-$ and of the corresponding branching ratios. These form factors describe the interaction between…
We present preliminary results of a determination of the semileptonic form factor for the decay of pseudoscalar heavy-light mesons to pseudoscalar light-light mesons in full QCD. In this preliminary study we focus on the effects of…
The off--shell electromagnetic vertex function of pions and kaons is studied in a bosonized Nambu--Jona-Lasinio model with a gauge--invariant proper--time cutoff. The slope of the pion form factor with respect to the pion 4--momentum is…
The pion electromagnetic form factor is calculated with a light-front quark model. The "plus" and "minus" component of the electromagnetic current are used to calculate the electromagnetic form factor in the Breit frame with two models for…
The mean free path of neutrino - free electron gas interaction has been calculated by taking into account the neutrino electromagnetic form factors and the possibility of neutrino oscillation. It is shown that the form factor effect becomes…
Two-particle two-hole contributions to electromagnetic response functions are computed in a fully relativistic Fermi gas model. All one-pion exchange diagrams that contribute to the scattering amplitude in perturbation theory are…