Shaouly Bar-Shalom — Page 4

arXiv1997

Flavor Changing Transitions and the Top Quark in a Two Higgs Doublets Model; Application to e^+e^- --> t bar-c nu_e bar-nu_e, t bar -c e^+ e^-, t bar-c Z, t --> cW^+W^- and t --> cZZ

Extension of the SM with one extra Higgs doublet may give rise to flavor-changing-scalar coupling of a neutral Higgs to a pair of top-charm quarks. This coupling gives rise to a large tree-level effective W^+W^-;ZZ - Higgs - t bar-c interaction. We find that the reactions e^+e^- --> t bar-c nu_e bar-nu_e, t bar-c e^+e^-, t bar-c Z and the two rare top decays t --> cW^+W^-, t --> cZZ are very sensitive probes of such an effective interaction. The most promising ones, e^+e^- --> t bar-c nu_e bar-nu_e, t bar-c e^+e^-, may yield several hundreds and up to thousands of such events at the Next Linear Collider with a center of mass energy of sqrt{s}=0.5-2 TeV if the mass of the light neutral Higgs is a few hundred GeV. We also find that the rare decays t --> cW^+W^- and t --> cZZ may be accessible in the LHC if the mass of the light neutral Higgs lies in the narrow window 150 GeV < m_h < 200 GeV.

hep-ph↗

arXiv1996

CP Nonconservation in $p\bar p\to t\bar b X$ at the Tevatron

The reaction $p\bar p\to t\bar bX$ is found to be rather rich in exhibiting several different types of CP asymmetries. The spin of the top quark plays an important role. Asymmetries are related to form factors arising from radiative corrections of the $tbW$ production vertex due to non-standard physics. As illustrations, effects are studied in two Higgs Doublet Models and in Supersymmetric Models; asymmetries up to a few percent may be possible.

hep-ph↗

arXiv1995

CP Nonconservation in $e^+e^-\to t\bar tg$

CP violation effects in $e^+ e^- \to t\bar tg$ are examined. CP-odd, $T_n$-odd and $T_n$-even observables can both be used to extract information on the real and imaginary parts of Feynman amplitudes. Two Higgs doublet model with CP violating phase from neutral Higgs exchange is used to estimate possible effects.

hep-ph↗