Related papers: Asymptotic behavior of pion form factors
We compute the Form Factors of both neutral and charged pion using a non-perturbative running of the strong coupling constant $\alpha_s$ obtained using a double-dilaton Holographic QCD model. These form factors remain poorly understood in…
We present a calculation of the nucleon electromagnetic form-factors as well as the pion and rho to pion transition form-factors in a hybrid calculation with domain wall valence quarks and improved staggered (Asqtad) sea quarks.
The simultaneous investigation of the pion electromagnetic form factor in the space- and time-like regions within a light-front model allows one to address the issue of non-valence components of the pion and photon wave functions. Our…
Motivated by the planned measurements of the time-like electromagnetic proton form factors an exploratory study of the time-like electromagnetic pion form factor is presented in a formalism which describes mesons as Poincar\'e-invariant…
We study the pion electromagnetic and $\gamma^* + \pi^0 \to \gamma$ transition form factors at intermediate momentum transfer. We calculate soft, nonperturbative corrections to the leading perturbative amplitudes which arise from the $q\bar…
Hadronic form factors fulfill dispersion relations and superconvergence sum rules for their spectral density as genuine imprints of QCD. We show several instances where these conditions are flagrantly violated due to the lack of information…
We analyze the pi -> gamma* gamma* amplitude in the framework of radial Regge models in the large-Nc limit. With the assumption of similarity of the asymptotic Regge rho and omega meson spectra we find that the pion distribution amplitude…
New precise experimental information on $\sigma_{tot}(e^+e^- \to \pi^+ \pi^-)$ is transferred into the space-like region, by taking advantage of the analyticity. As a result a rigorous pion electromagnetic form factor behavior is obtained.…
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.
The pion wave function is discussed in the light of the recent CLEO data on the pion gamma transition form factor. It turns out that the wave function is close to the asymptotic form whereas wave functions strongly concentrated in the…
An interplay of perturbative and nonperturbative effects in pomeron, odderon and reggeons dynamics is discussed. It is pointed out that experimental data on pion charge exchange reaction at high energies indicate to a dominance of the…
The behavior of the transition pion form factor for processes \gamma^*\gamma -> \pi^0 and \gamma^* \gamma^* -> \pi^0 at large values of space-like photon momenta is estimated within the nonlocal covariant quark-pion model. It is shown that,…
Electroproduction of $\pi^+$ above the resonance region is analyzed in the Regge model for $\pi+\rho$ exchanges. Importance of the roles of pion and proton form factors in the process is discussed in comparison with existing models of…
A simple model of a composite nucleon is developed in which a fermion and a boson, representing quark and diquark constituents of the nucleon, form a bound state owing to a contact interaction. Photon and pion couplings to the quark provide…
I describe recent advances in our understanding of the hadronic form factors governing semileptonic meson transitions. The resulting framework provides a systematic approach to the experimental data, as a means of extracting precision…
We adopt a non-perturbative relativistic constituent-quark model for the pi-meson electromagnetic form factor, which have successfully predicted experimental results, and supplement it with the effective momentum-dependent quark mass to…
In this work, we employ a dispersion relation that allows to recover the electromagnetic form factor of the pion from its modulus along the unitarity cut. Unlike the standard dispersive approach, this method extends in a straightforward…
The discussion on the asymptotical behaviour of the form factors in the space-like and time-like regions have been corrected and clarified. Fig.3 has been replaced by an improved analysis of the data.
Investigation of the spacelike and timelike electromagnetic form factors of hadrons, within a relativistic microscopical model characterized by a small set of hypothesis, could shed light on the components of hadron states beyond the…
We write down some relevant matrix elements for the scattering and decay processes of the pion by considering a quark-meson vertex function. The pion charge and transition form factors $F_\pi$, $F_{\pi\gamma}$, and $F_{\pi\gamma^*}$ are…