相关论文: Polarization Effects on the $e+e- \to W^+W^-$ proc…
We calculate the Coulomb effects on the cross section for e+ e- --> W+ W- taking into account the instability of the W bosons. We carefully explain the consequences of instability throughout the energy range which will be accessible at…
Beam polarisation is an integral part of the physics case of future Linear Colliders. In this contribution, important examples from Higgs coupling measurements, top and electroweak physics at high energies, the Z pole program as well as…
A direct measurement of the trilinear $WW\gamma$ and $WWZ$ couplings is possible in the pair production of electroweak bosons at $e^+e^-$ and hadron colliders. This talk addresses some of the theoretical issues: the parameterization of…
We discuss in detail top quark polarization in above-threshold (t \bar t)-production at a polarized linear e^+ e^- collider. We pay particular attention to the minimization and maximization of the polarization of the top quark by tuning the…
At a future linear collider, a polarized electron beam will play an important role in interpreting new physics signals. Backgrounds to a new physics reaction can be reduced by choice of the electron polarization state. The origin of a new…
The differential cross section and some polarization observables have been calculated for the $e^+\,e^-\to \gamma\,\gamma$ reaction taking into account the contribution of the heavy excited electron and the general form…
The cross section of high-energy $e^+e^-$ pair production by a heavy charged particle in the atomic field is investigated in detail. We take into account the interaction with the atomic field of $e^+e^-$ pair and a heavy particle as well.…
When polarized electrons traverse a region where the laser light is focused their polarization varies even if their energy and direction of motion are not changed. This effect is due to interference of the incoming electron wave and an…
A theoretical investigation of the radiative capture of an electron into a bound state of heavy, hydrogen-like ion is presented. Special attention is paid to the question of how the linear polarization of the emitted radiation is affected…
Spin-polarization effects of an ultrarelativistic electron beam head-on colliding with an ultraintense two-color laser pulse are investigated comprehensively in the quantum radiation-dominated regime. We employ a Monte Carlo method, derived…
The polarization dependent momentum distributions of top quarks and their decay products are calculated for $t\bar t$ production at future $e^+e^-$ colliders with polarized beams. The Green function formalism is applied to this reaction…
For the processes e+e-\to \mu+\mu-, \tau+\tau-, b\bar{b} and c\bar{c} at a future e+e- collider with \sqrt{s}=0.5 TeV, we examine the sensitivity of the helicity cross sections to four-fermion contact interactions. If longitudinal…
Extra neutral gauge bosons suggested by models beyond the standard model can indirectly show up in $e^{+} e^{-}$ collisions through off-resonance deviations of various physical observables from the corresponding standard model values. We…
Electron-positron pair production by means of vacuum polarization in the presence of strong electromagnetic (EM) field of two counterpropagating laser pulses is studied. A 3-dimensional model of the focused laser pulses based on the…
The complementarity of $e^+e^-$ and $\gamma \gamma$ colliders to discover and explore new physics beyond the Standard Model(SM) is discussed. After briefly surveying a number of various new physics scenarios we concentrate in detail on…
We study the production processes e^+ e^- -> chi^+_i chi^-_j, i,j=1,2, and e^+ e^- -> chi^0_m chi^0_n, m,n=1,...,4, working out the advantages of polarizing both beams. For e^+ e^- -> chi^+_1 chi^-_1 with chi^-_1 -> chi^0_1 e^- nu and e^+…
Full one-loop electroweak-corrections for an $e^-e^+\rightarrow t \bar{t}$ process associated with sequential $t\rightarrow b \mu\nu_\mu$ decay are discussed. At the one-loop level, the spin-polarization effects of the initial electron and…
We investigate the effects of the bottom-quark induced processes on the doubly polarized cross sections of $W^+W^-$ pair production at the LHC. The method to extract the on-shell single-top contribution is provided. Results for…
We investigate the anomalous $W^+W^-\gamma$ couplings through the process $e^-e^+\,\rightarrow\,\nu_e\bar{\nu}_e\gamma$ for unpolarized and polarized electron (positron) beams at the International Linear Collider. We give the 95$\%$…
We describe a generator for the process $e^+e^- \to W^+W^-$ including all one-loop and leading log photonic two-loop contributions. It includes polarization of the beam and $W$ bosons, and the possibility to study the effect of anomalous…