Related papers: Photon-pion transition form factor: BABAR puzzle i…
We study selected meson transition processes and associated form factors within a model of QCD based on the Dyson--Schwinger equations truncated to ladder-rainbow level. The infrared structure of the ladder-rainbow kernel is described by…
We study the phenomenon of duality in hard exclusive reactions to which QCD factorization applies. Considering "two-photon"-like processes in the scalar $\phi^3_E$ model and also hadron-pair production from the collisions of a real…
The H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F_pi) was extracted from the data by comparing the…
We develop and discuss in technical detail an infrared-finite factorization and optimized renormalization scheme for calculating exclusive processes, which enables the inclusion of transverse degrees of freedom without entailing suppression…
Elastic and semileptonic transition form factors for the kaon and pion are calculated using the leading-order in a global-symmetry-preserving truncation of the Dyson-Schwinger equations and a momentum-independent form for the associated…
Motivated by recent BABAR measurements of the $\gamma^*\to\gamma \eta$ and $\gamma^*\to\gamma \eta^\prime $ transition form factors, we estimate two-photon exchange contributions to the corresponding cross sections. By using a…
The electromagnetic form factors of pion and nucleon are considered within the framework of the Quark-Gluon Strings Model, where the dependence of the form factors on $q^2$ is determined by the intercept of a dominant Regge trajectory and…
Using non-local chiral quark model with simple pole ansatz for mass dependence on momentum and non-local currents satisfying Ward-Takahashi identities, we calculate pion to photon transition distribution amplitudes and relevant form…
Recent experimental and theoretical advancements have led to significant progress in our understanding of the electromagnetic structure of nucleons ($N$), nucleon excitations ($N^\ast$), and other baryons. These breakthroughs have been made…
In this work, we discuss both relativistic and perturbative QCD corrections to the transition form-factor ${\cal F}_{\eta_Q}{(t_1,t_2)}$ for the process $\gamma^*(q_1) \gamma^*(q_2) \leftrightarrow \eta_Q(P)$ with dependencies on the…
Measuring the lepton anomalous magnetic moments $(g-2)$ and the rare decays of light pseudoscalar mesons into lepton pairs $P\to l^{+}l^{-} $, serve as important tests of the Standard Model. To reduce the theoretical uncertainty in the…
We compute the radiative corrections to the process of two-pion production in association with a hard photon in $e^+ e^-$ annihilation by taking into account the non-perturbative structure of the pion in the one-loop calculation. For this…
Factorization scheme analysis of $F_2^{\gamma}(x,Q^2)$ in the next-to-leading order QCD is revisited. It is emphasized that the presence of the inhomogeneous term in the evolution equations for quark distribution functions of the photon…
Right now, we have not enough knowledge to determine the hadron distribution amplitudes (DAs) which are universal physical quantities in the high energy processes involving hadron for applying pQCD to exclusive processes. Even for the…
The form factor $F_{3\pi}(s,t,u)$ for the anomalous process $\gamma^\ast \pi \rightarrow \pi \pi$ is calculated in the isospin limit for several values of the light current-quark mass (i.e., the pion mass) using Dyson-Schwinger and…
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 report results on the $\pi$-$\gamma$ transition form factor obtained within the hard scattering approach including transverse momentum effects and Sudakov corrections. The results clearly favor distribution amplitudes close to the…
We present a status report of our calculation of the electromagnetic form factor of the pion on the PACS-CS gauge field configurations generated using Iwasaki gauge action and Wilson-clover quark action for 2 + 1 flavors of light dynamical…
Results of the Spectral Quark Model for the gravitational, electromagnetic, and transition form factors of the pion are discussed. In this model both the parton distribution amplitude and the parton distribution function are flat, in…
The concept of incomplete vector-meson dominance and Regge models is applied to the transition form factor of the pion. First, we argue that variants of the chiral quark model fulfilling the chiral anomaly may violate the Terazawa-West…