Related papers: Transverse beam polarization and limits on leptoqu…
We show how transverse beam polarization at $e^+e^-$ colliders can provide a novel means to search for CP violation by observing the distribution of a single final-state particle without measuring its spin. We suggest an azimuthal asymmetry…
We consider the most general gauge-invariant, chirality-conserving contact interactions in the process e +e- -> gamma Z, of the type proposed Abraham and Lampe, in order to explore the possibility of CP violation at future linear colliders…
Transverse polarization (TP) can be used to study interference of (S,P) or T type couplings from new physics with the SM contribution. In e+e- -> t tbar, a CP-odd azimuthal asymmetry can constrain the scale Lambda of new (S,P) or T contact…
In the presence of an electric dipole coupling of the top quark to a photon, and an analogous "weak" dipole coupling to the Z, CP violation in the process e+e- -> t tbar leads to the polarization of the top and anti-top. This polarization…
The effect of anomalous chromomagnetic (mu) and chromoelectric couplings (d) of the gluon to the top quark are considered in e+ e- --> t tbar, with unpolarized and longitudinally polarized electron beams. The total cross section, as well as…
CP-violating asymmetries due to a possible electric dipole interaction of the top quark in the production and subsequent decay of top quark-top antiquark pair in photon-photon collisions are studied. The asymmetries defined can be used to…
CP-violating asymmetries in the processes e+e- -> t tbar and gamma gamma -> ttbar can provide information about CP-violating couplings of the top quark, whose presence would signal physics beyond the standard model. Work on studies of…
In the presence of an electric dipole coupling of t-tbar to a photon, and an analogous "weak" dipole coupling to the Z, CP violation in the process e+e- --> t tbar results in modified polarization of the top and anti-top. This polarization…
We show how to determine the electric and weak dipole moments of the top quark simultaneously and independently from $e^+e^-\to t\bar t$ at $\sqrt{s}=500$ GeV NLC. To obtain the best accuracies with which the dipole moments can be measured,…
The energy spectra of the b and bbar quarks in e+e- -> t tbar with t -> b W (tbar -> bbar W) are calculated assuming CP violation in the production process. Expressions for the corresponding CP violating asymmetries and optimal observables…
New CP-violating asymmetries of decay leptons in $e^+\,e^-\;\ra\;t\,\bar{t}$, arising from electric and weak dipole couplings of $t\,\bar{t}$ to $\gamma$ and $Z$, are examined in the case of unpolarized and longitudinally polarized…
An optimal-observable analysis of the angular and energy distributions of the leptons and bottom quarks in the process e+e- --> tt-bar --> l^{+-}/b(b-bar)... has been performed in order to measure the most general top-quark couplings to…
Top quark production in the process $e^+e^- \rightarrow t\bar{t}$ at a future linear electron positron collider with polarized beams is a powerful tool to determine the scale of new physics. Studies at the $\ttbar$ threshold will allow for…
The effect of anomalous chromoelectric couplings of the gluon to the top quark are considered in e+ e- --> t tbar. The total cross section, as well as t and tbar polarizations are calculated to order alpha_s in the presence of the anomalous…
We examine very general four-point interactions arising due to new physics contributing to the Higgs production process e+e- --> HZ. We write all possible forms for these interactions consistent with Lorentz invariance. We allow the…
We consider the possibility of observing deviations from the Standard Model gauge-boson self-couplings at a future $500$~GeV $e^+ e^-$ linear collider. We concentrate on the case in which the electroweak symmetry breaking sector is strongly…
We study how to probe the anomalous CP-violating couplings of top quark with photon, Z and gluon in the ttbar threshold region at future e+e- colliders. These couplings contribute to the difference of the t and tbar polarization vectors…
We study two simple $CP$-violating asymmetries of leptons coming from the decay of $t$ and $\o t$ in $e^+e^- \ra \tt$, which do not need the full reconstruction of the $t$ or $\o t$ for their measurement. They can arise when the top quark…
We study neutralino production at the linear collider with the subsequent two-body decays ~chi^0_i -> ~chi^0_n Z^0 and Z^0 -> l^+ l^-, with l=e, mu, tau, or Z^0 -> q q- with q=c,b. We show that transverse electron and positron beam…
We study the potential of future lepton colliders to probe violation of the CP symmetry in the top quark sector. In certain extensions of the Standard Model, such as the two-Higgs-doublet model (2HDM), sizeable anomalous top quark dipole…