Related papers: Excited electron contribution to the e+e- -> \gamm…
We study the sensitivity to the Z' couplings of the processes $e^+e^-\to l^+l^-,\bar{b}b$ and $\bar{c}c$ at the linear collider with $\sqrt{s}=500 GeV$ with initial beam polarization, for typical extended model examples. To this aim, we use…
We propose a semi-empirical formula for the cross section of ionization by electron impact. The formula involves adjustable parameters which are determined by comparison with measured or numerically calculated cross sections. In the latter…
The cross sections of high-energy $\mu^+\mu^-$ pair production and paradimuonium production by a relativistic electron in the atomic field are discussed. The calculation is performed exactly in the parameters of the atomic field. Though the…
The amplitude for the anomalous process gamma pi -> pi pi is evaluated to two loops in the chiral expansion by means of a dispersive method. The two new coupling constants that enter at this order are estimated via sum rules derived from a…
We study the single production of excited spin-3/2 and spin-1/2 leptons in future high energy $e^+e^-$ collisions. We calculate the production cross section and decay widths of excited spin-3/2 and spin-1/2 leptons according to their…
The construction of differential cross sections as a function of excitation energy for systems with a collection of low- and high-lying intrinsic vibrational modes has been attempted in the past. A prescription is proposed that simplifies…
We compare the predictions of different variants of chiral effective field theory for the gamma-p elastic scattering differential cross section. We pay particular attention to the role of pion loops, and the impact that a heavy-baryon…
The latest molecular data - potential energy curves and Rydberg$/$valence interactions - characterizing the super-excited electronic states of CO are reviewed, in order to provide inputs for the study of their fragmentation dynamics.…
The ee -> ee+pi0+X and ee -> ee+K0s+X reactions are studied at LEP using data collected with the L3 detector at sqrt{s}=189-202 GeV. Preliminary results for the differential cross section dsigma/dpt in the transverse momentum range 0.2 GeV…
We analyze the single and pair production of excited neutrinos at the CLIC through the processes $e^{+}e^{-}\rightarrow \nu^{*} \bar{\nu}$, $e^{+}e^{-} \rightarrow e^{+}\gamma^{*} e^{-} \rightarrow e^{+} \nu^{*} W^{-}$, and $e^{+}e^{-}…
An effective field theory calculation of the n+p->d+gamma cross section accurate to 1% for center of mass energy E up to ~1 MeV is presented. At these energies, which are relevant for big-bang nucleosynthesis, isovector magnetic transitions…
The cross section of the process e+e- -> pi+pi- has been measured using about 114000 events collected by the CMD-2 detector at the VEPP-2M e+e- collider in the center-of-mass energy range from 0.61 to 0.96 GeV. Results of the pion form…
Strong coupling with circularly polarized vacuum fluctuations offers a viable route to manipulate molecular chirality. While experiments are advancing toward the realization of chiral cavities, a mean-field theoretical framework for…
A general formalism is developed to calculate the cross section and the polarization observables for the reaction $\bar N+N\to \pi +\ell^++\ell^-$. The matrix element and the observables are expressed in terms of six scalar amplitudes…
We calculate the contributions of the axial current to top quark pair production in e+ e- annihilation at threshold. The QCD dynamics is taken into account by solving the Lippmann-Schwinger equation for the P wave production using the QCD…
We calculate in closed form the complete ${\mathcal O}(\alpha_s^2)$ color-singlet differential cross section for $e^+e^- \to \gamma^* \to \psi_Q+X$ scattering. The cross section reduces at high energies to a heavy quark fragmentation form.…
This report presents a review of the studies made in the working group on gamma gamma and e gamma physics" of the ECFA/DESY workshop on linear collider physics. It reports on several new physics studies, in particular s-channel Higgs…
The reaction $\gamma d\to \pi^+ nn$ is calculated up to order $\chi^{5/2}$ in chiral perturbation theory, where $\chi$ denotes the ratio of the pion to the nucleon mass. Special emphasis is put on the role of nucleon--recoil corrections…
A variant of quantum electrodynamics coupled to a dark photon through a kinetic mixing is studied. The analogous of the light-light diagram becomes the conversion process $\gamma'\gamma' \to \gamma \gamma$ and an expression for the…
The e+e- -> pi+pi-pi+pi- cross section has been measured using 5.8/pb of integrated luminosity collected with the CMD-2 detector at the VEPP-2M collider. Analysis of the data with a refined efficiency determination and use of both three-…