scholarly journals CP-ODD NEUTRAL HIGGS EFFECTS IN $t\bar t$ PRODUCTION

1994 ◽  
Vol 09 (07) ◽  
pp. 1097-1114 ◽  
Author(s):  
A. PILAFTSIS ◽  
M. NOWAKOWSKI
Keyword(s):  
Higgs Boson ◽  
Cp Violation ◽  
Higgs Doublet ◽  
Finite Width ◽  
Higgs Potential ◽  
Neutral Higgs Boson ◽  
Initial State ◽  
Cp Asymmetry ◽  
Doublet Model ◽  
Two Higgs Doublet Model

We study CP violation in the process [Formula: see text] at an e+e− TeV collider. As the source of CP violation we assume a two-Higgs doublet model with an explicitly CP- noninvariant Higgs potential. The finite width effects of the neutral Higgs boson in the subprocess reaction, [Formula: see text], give rise to CP-odd observables which can have sizeable values. CPT constraints due to final (initial) state interactions are also taken into account. Numerical estimates of the expected CP asymmetry are given.

scholarly journals Direct CP violation in $$D^+ \rightarrow K^0({\bar{K}}^0) \pi ^+$$ decays as a probe for new physics

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
David Delepine ◽  
Gaber Faisel ◽  
Carlos A. Ramirez
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Parameter Space ◽  
Higgs Doublet ◽  
New Physics ◽  
Cp Asymmetry ◽  
The Standard Model ◽  
Doublet Model ◽  
Two Higgs Doublet Model ◽  
Cp Asymmetries

Abstract In this paper we investigate CP violation in charged decays of D meson. Particularly, we study the direct CP asymmetry of the Cabibbo favored non-leptonic $$D^+ \rightarrow {\bar{K}}^0 \pi ^+$$D+→K¯0π+ and the doubly Cabibbo-suppressed decay mode $$D^+ \rightarrow K^0 \pi ^+$$D+→K0π+ within standard model, two Higgs doublet model with generic Yukawa structure and left right symmetric models. In the standard model, we first derive the contributions from box and di-penguin diagrams contributing to their amplitudes which are relevant to the generation of the weak phases essential for non-vanishing direct CP violation. Then, we show that the generated phases are so tiny leading to null direct CP asymmetries of both decay modes. Regarding the two Higgs doublet model with generic Yukawa structure, after taking into account all constraints on the parameter space of the model, we show that the weak phases of the amplitudes can be enhanced compared to the standard model ones. However, the enhancement is still not enough to have sizable direct CP asymmetries. Finally, within left right symmetric models, we find that $$|A^{SM+LR}_{CP} (D^+ \rightarrow {\bar{K}}^0 \pi ^+)|\lesssim \mathcal {O}(10^{-3})$$|ACPSM+LR(D+→K¯0π+)|≲O(10-3) after respecting all relevant constraints on the parameter space of the model.

scholarly journals Exploring new physics contributions to CP violation in $$\tau ^- \rightarrow K^-\pi ^0\nu _{\tau } $$

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
David Delepine ◽  
Gaber Faisel ◽  
Carlos A. Ramirez
Keyword(s):  
Cp Violation ◽  
Decay Rate ◽  
Standard Model Prediction ◽  
Form Factors ◽  
Higgs Doublet ◽  
Tensor Operator ◽  
Effective Hamiltonian ◽  
Cp Asymmetry ◽  
Doublet Model ◽  
Two Higgs Doublet Model

AbstractA general analysis of possible violation of CP in processes like $$\tau \rightarrow K\pi \nu $$ τ → K π ν , for unpolarized $$\tau $$ τ is presented. In this paper, we derive the new contributions to the effective Hamiltonian governs $$\vert \Delta S \vert =1$$ | Δ S | = 1 semileptonic tau decays in the framework of two Higgs doublet model with generic Yukawa structure and Leptoquarks models. Within these models, we list all operators, in the effective Hamiltonian and provide analytical expression for their corresponding Wilson coefficients. Moreover, we analyze the role of the different contributions, originating from the scalar, vecor and tensor hadronic currents, in generating direct CP asymmetry in the decay rate of $$\tau ^-\rightarrow K^-\pi ^0\nu _\tau $$ τ - → K - π 0 ν τ . We show that non vanishing direct CP asymmetry in the decay rate of $$\tau ^-\rightarrow K^-\pi ^0\nu _\tau $$ τ - → K - π 0 ν τ can be generated due to the presence of both, the weak phase in the Wilson coefficient corresponding to the tensor operator and the strong phase difference resulting from the interference between the form factors expressing the matrix elements of the vector and tensor hadronic currents. After taking into account all relevant constraints, we find that the generated direct CP asymmetry is of order $$10^{-8}$$ 10 - 8 which is several orders of magnitude larger than the standard model prediction. We show also that, in two Higgs doublet model with generic Yukawa structure , direct local or non integrated CP violation can be as large as 0.3 % not far from experimental possibilities. This kind of asymmetry can be generated due to the interference between vector and scalar contributions with different weak phases which is not the case in the SM.

ON THE WEINBERG MODEL OF CP VIOLATION

1992 ◽  
Vol 07 (06) ◽  
pp. 1059-1095 ◽  
Author(s):  
HAI-YANG CHENG
Keyword(s):  
Higgs Boson ◽  
Cp Violation ◽  
B Physics ◽  
Higgs Doublet ◽  
Charged Higgs Boson ◽  
Neutron Electric Dipole Moment ◽  
Neutral Higgs Boson ◽  
Boson Exchange ◽  
Charged Higgs ◽  
Doublet Model

The Weinberg three-Higgs-doublet model of CP violation and its phenomenological implications are reviewed. CP violation which arises solely from charged-Higgs-boson exchange can be accommodated in the kaon system, but it is not compatible with the constraints inferred from the neutron electric dipole moment dn and from B physics. Therefore, charged-Higgs-boson exchange cannot be the dominant source of CP violation observed in KL decays. Limits on CP violation mediated by neutral-Higgs-boson exchange are derived from the dn induced by the mechanism of Barr and Zee.

mixing, CP violation, and B→KγX in a two-Higgs-doublet model

1990 ◽  
Vol 337 (2) ◽  
pp. 284-312 ◽  
Author(s):  
Andrzej J. Buras ◽  
Paweł Krawczyk ◽  
Markus E. Lautenbacher ◽  
Claudia Salazar
Keyword(s):  
Cp Violation ◽  
Higgs Doublet ◽  
Doublet Model ◽  
Two Higgs Doublet Model

scholarly journals PATHWAYS TO TESTABLE LEPTOGENESIS

2010 ◽  
Vol 25 (07) ◽  
pp. 501-509 ◽  
Author(s):  
PEI-HONG GU ◽  
UTPAL SARKAR
Keyword(s):  
Higgs Doublet ◽  
Neutrino Masses ◽  
High Scale ◽  
Cp Asymmetry ◽  
Decay Products ◽  
Doublet Model ◽  
Mass Degeneracy ◽  
Three Body ◽  
Two Higgs Doublet Model ◽  
Very High

In the conventional seesaw models of neutrino masses, leptogenesis occurs at a very high scale. Three approaches have been discussed in the literature to lower the scale of leptogenesis making them testable: mass degeneracy, hierarchy of couplings and three-body decays. We advocate yet another approach to a testable leptogenesis, whereby the decaying particles could go out of equilibrium at an accessible scale due to kinematics, although their couplings to the decay products are larger for generating a desired CP asymmetry. We demonstrate this new possibility for the testable leptogenesis in a two-Higgs doublet model where the neutrino masses originate from a one-loop diagram.

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