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B. Grzadkowski

Publications and source records attributed to B. Grzadkowski.

40 records · Page 3Linked to original sources

CP Violation in {\boldmath $H \ra t \overline{t}$} Decays at {\boldmath $\epem$} Colliders

A helicity asymmetry for top quarks originating from Higgs boson decays is investigated within the 2-Higgs Doublet Model. The asymmetry is sensitive to CP violation in the scalar sector of the model, whereas it vanishes in the Standard Model. It has been checked that without any fine tuning of parameters the asymmetry can reach $50\%$. Standard decay patterns $\twbdec$ and $\tbwbdec$ are utilized as spin analyzers to measure the asymmetry. The Higgs production mechanism considered here is $\hprod$. It has been shown that signal from the asymmetry can easy overcome the noise for Higgs bosons produced in future linear $\epem$ colliders at energy $\sqrt{s}=500\gev$ operating with integrated luminosity $L=2.0\times10^4\lumun$.

hep-ph↗

The Decay Rate Asymmetry of the Top Quark

The asymmetries ${\cal A}_k \equiv [Γ(\twddec) -Γ(\tbwddec)] /[Γ(\twddec) + Γ(\tbwddec)]$ in the partial widths of the top quark decays are discussed within the Standard Model (SM), the Two-Higgs-Doublet Model (2HDM) and supersymmetric extensions of the SM (SSM). The leading contributions to these asymmetries in the SM and in the 2HDM are induced by the up-type quark self-energy diagrams and are found to be very small. However, in the SSM, the asymmetry ${\cal A}_b$ can be substantial, ${\cal O}(α_{QCD})$, provided the CP-violating phase of gluino-top-stop couplings is not suppressed. Within the SSM ${\cal A}_b$ is generated by the vertex corrections.

hep-ph↗

Using Back-Scattered Laser Beams to Detect CP Violation in the Neutral Higgs Sector

We demonstrate that the ability to polarize the photons produced by back-scattering laser beams at a TeV scale linear $\epem$ collider could make it possible to determine whether or not a neutral Higgs boson produced in photon-photon collisions is a CP eigenstate. The relative utility of different types of polarization is discussed. Asymmetries that are only non-zero if the Higgs boson is a CP mixture are defined, and their magnitudes illustrated for a two-doublet Higgs model with CP-violating neutral sector.

hep-ph↗