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Toshio Hayashi

Publications and source records attributed to Toshio Hayashi.

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Right-Handed b to c and u Coupling Model and CP Violation

We investigate CP violation in the purely right-handed b quark to c- and u- quark coupling model under the constraint of right-handed W-gauge boson mass M_R > 720 GeV , which is experimentally obtained recently by D0 Collaboration at Fermilab. By using the data on $K_L-K_S$ mass difference, CP violating parameter $ε$ in the neutral kaon system and $B_d-\bar B_d$ mixing, together with the new data of $Br (B^-\to ψπ^-) /Br (B^-\to ψK^-) = 0.052 \pm 0.024 (\approx \mid V_{cd}/V_{cs} \mid^2)$, we can fix all of the three independent angles and one phase of the right-handed mixing matrix V^R. Under these constraints, another CP-violating parameter $ε'/ε$ and electric dipole moment of neutron are shown to be consistent with the data in our model. The pattern of CP violation in the nonleptonic decay of $B_d(B_s)$ mesons to CP eigenstates is different from that in the Standard Model.

hep-ph

CP Violation in $t\to W^+ b$ Decays in Two-Higgs Doublet Model

Due to the large mass of top quark, CP violation in the top-quark decay is sensitive to the interactions mediated by Higgs bosons. We consider CP violation in $t\rightarrow W^+ b$ decay by calculating consistently in unitary gauge the CP-violating up-down asymmetry of the leptons from $W$ boson decays in $t\rightarrow W^+ b$, defined by Grzcadkowski and Gunion, in the two-Higgs doublet model with CP-violating neutral sector. The asymmetry is shown to be at most of the order of $(1-3)\times 10^{-4}$ for $\tanβ=1.0$, where $\tanβ$ is the ratio of vacuum expectation values for the two neutral Higgs bosons.

hep-ph