Related papers: $\Delta$ contribution in $e^+ + e^- \to p + \bar{p…
The aim of this work is to give a pedagogical derivation of polarization observables for the annihilation reaction $e^+ + e^- \to N+ \bar N$. The reaction mechanism is one photon + two photon exchange, the last is described by axial…
We estimate two-photon exchange contribution to the process $e^+ +e^- \to p + \bar{p}$. The two-photon exchange corrections to double spin polarization observables and form factors in the time-like region are calculated. The corrections are…
Polarization observables for the reaction $\bar p+p\to e^++e^-$ are given in terms of three independent complex amplitudes, in presence of two photon exchange. General expressions for the differential cross section and the polarization…
We calculate the effects on the elastic electron-proton scattering cross section of the two-photon exchange contribution with an intermediate $\Delta$ resonance. The $\Delta$ two-photon exchange contribution is found to be smaller in…
The expressions for the differential cross section and of the polarization observables for the reaction $\bar p+p\rightarrow e^++e^-$ are given in terms of the nucleon electromagnetic form factors in the laboratory system. Radiative…
The differential cross section and the polarization observables for $\Delta $--isobar production in the deuteron electrodisintegration process, $e^-+d\to e^-+\Delta +N$, are calculated in a general formalism based on structure functions.…
We present an evaluation of a two-photon exchange correction to the cross section for unpolarized $\Delta$ isobar production in electron-proton collisions, using a relativistic, crossing symmetric and gauge invariant approach. The…
A detailed investigation of the theoretical ambiguities present in the QCD description of photon production in $e^+e^-$ annihilation is given. It is pointed out that in a well-defined perturbative analysis it is necessary to subtract the…
We revise the radiative corrections to double-Dalitz decays ($P\to\ell\bar{\ell}\ell'\bar{\ell}'$), completing the full next-to-leading order calculation in QED as compared to existing calculations. As a result, we find mild differences…
Misprints in the C_F^2 part of the splitting function \Delta P_{gq}^(1) Eq. (3.29) are corrected. Due to a minus sign error between the C_F^2- 1/2 C_A C_F piece and the remaining part of Eq. (A.4), Eq. (3.46) is changed. Finally…
In this paper, we study the processes of $e^{+}e^{-}$ annihilation into two body final states, either two pseudoscalar mesons or one meson with a photon. The hadronic vacuum polarization form factors are calculated within the framework of…
The distributions of the bottom quark in the process $e^+ e^- \to t \, \bar{t} \to b \, W^+ \, \bar{t}$ are considered at the $e^+ e^-$ energy corresponding to the first construction stage of the Compact Linear Collider. The cross sections…
The dependence of the differential cross section and polarization observables in the $\bar N+N\to \pi +e^++e^-$ reaction on the polarizations of the proton target and antiproton beam (the produced electron may be unpolarized or…
The precision of fixed-order calculations on the dihadron production in electron-positron annihilation is paramount for probing QCD factorization and constraining non-perturbative inputs. This paper investigates the QCD corrections to the…
We extend previous calculations of polarization observables for the annihilation reaction $\bar p +p\to \ell^{-}+\ell^{+}$ to the case of heavy leptons, such as the $\tau$-lepton. We consider the case when the beam and/or the target are…
General properties of the differential cross section and of the polarization observables are derived for the $e^++e^-\to N+\bar N$ reaction, in presence of two--photon exchange. Polarization effects are investigated for longitudinally…
We revisit the question of the contributions of two-photon exchange with $\Delta(1232)$ excitation to the electron-proton scattering in a hadronic model. Three improvements over the previous calculations are made, namely, correct vertex…
The contribution of pseudoscalar pole diagrams to the hadronic light-by-light corrections of order alpha^3 E_F to the ground state hyperfine splitting in hydrogenic atom is calculated in the pseudoscalar pole terms approximation. The vector…
We analyze the decay modes of $D/D_s\to PP,PV$ on the basis of a hybrid method with the generalized factorization approach for emission diagrams and the pole dominance model for the annihilation type contributions. Our results of PV final…
The s-channel annihilation of proton and antiproton into a neutral pion and a real or virtual photon followed by lepton pair emission is studied. Such mechanism is expected to play a role at moderate values of the total energy $\sqrt{s}$,…