scholarly journals A TWO HIGGS BI-DOUBLET LEFT-RIGHT MODEL WITH SPONTANEOUS CP VIOLATION

2008 ◽  
Vol 23 (21) ◽  
pp. 3304-3308 ◽  
Author(s):  
YUE-LIANG WU ◽  
YU-FENG ZHOU
Keyword(s):  
Cp Violation ◽  
Mass Difference ◽  
Meson Mass ◽  
Symmetric Model ◽  
Family Symmetry ◽  
Cp Asymmetry ◽  
Ckm Matrix ◽  
K Meson ◽  
Flavor Changing ◽  
The Right

We discuss a left-right symmetric model with two Higgs bi-doublet and spontaneous P and CP violation. The flavor changing neutral currents is suppressed by assuming approximate global U(1) family symmetry. We calculate the constraints from neural K meson mass difference ΔmK and demonstrate that a right-handed gauge boson W2 contribution in box-diagrams with mass around 600 GeV is allowed due to a negative interference with a light charged Higgs boson around 150 ~ 300 GeV. The W2 contribution to ɛK is suppressed from appropriate choice of additional CP phases appearing in the right-handed Cabbibo-Kobayashi-Maskawa(CKM) matrix. The model is found fully consistent with B0 mass difference and the mixing-induced CP asymmetry measurements.

scholarly journals General CP violation in minimal left–right symmetric model and constraints on the right-handed scale

2008 ◽  
Vol 802 (1-2) ◽  
pp. 247-279 ◽  
Author(s):  
Yue Zhang ◽  
Haipeng An ◽  
Xiangdong Ji ◽  
Rabindra N. Mohapatra
Keyword(s):  
Cp Violation ◽  
Symmetric Model ◽  
The Right

scholarly journals QUARK MASS HIERARCHY AND CP VIOLATION IN LOW ENERGY SUPERSYMMETRY

1996 ◽  
Vol 11 (23) ◽  
pp. 4307-4319 ◽  
Author(s):  
CHUN LIU
Keyword(s):  
Cp Violation ◽  
Quark Mass ◽  
Neutral Current ◽  
Vacuum Expectation ◽  
Discrete Symmetry ◽  
Low Energy ◽  
Tree Level ◽  
Mass Hierarchy ◽  
Family Symmetry ◽  
Flavor Changing

A pattern of quark mass hierarchy and CP violation within the framework of low energy supersymmetry is described. By assuming some discrete symmetry among the three families, the quarks of the third family obtain masses at tree level. The second family obtains masses radiatively at one-loop level due to the soft breaking of the family symmetry. At this level, the first family remains massless by some degeneracy conditions of the squarks. As a result of R parity violation, the sneutrino vacuum expectation values are nonvanishing. CP violation occurs through the superweak sneutrino exchange. This picture is consistent with the experiments on the flavor-changing neutral current.

SPONTANEOUS CP VIOLATION IN A TWO-GENERATION LEFT-RIGHT SYMMETRIC MODEL WITH TWO HIGGS BI-DOUBLETS

1992 ◽  
Vol 07 (34) ◽  
pp. 3179-3186 ◽  
Author(s):  
AMBAR GHOSAL ◽  
ASIM K. RAY ◽  
SASWATI SARKAR
Keyword(s):  
Cp Violation ◽  
Relative Phase ◽  
Vacuum Expectation ◽  
Discrete Symmetry ◽  
Tree Level ◽  
Model Parameters ◽  
Symmetric Model ◽  
Expectation Values ◽  
Flavor Changing ◽  
Experimental Values

We discuss a two-generation left-right symmetric model with two Higgs bi-doublets and a discrete symmetry to show that spontaneous CP violation arises as a result of soft breaking of the discrete symmetry. The contributions to the CP violation parameter ε in the [Formula: see text] transition come from the box diagrams due to WL-WR exchanges as well as from the mixing of the real and imaginary parts of the flavor changing neutral Higgs at the tree level and both contributions depend on the relative phase difference between the vacuum expectation values (vevs) of the relevant neutral Higgs scalars. Other CP violating effects in the model are consistent with their experimental values for the appropriate choice of the model parameters. The extension of the model to the realistic case of three generations of fermions does not appreciably change the phenomenology of the model.

scholarly journals Resonant enhancement in leptogenesis

2018 ◽  
Vol 33 (05n06) ◽  
pp. 1842003 ◽  
Author(s):  
P. S. B. Dev ◽  
M. Garny ◽  
J. Klaric ◽  
P. Millington ◽  
D. Teresi
Keyword(s):  
Lower Bound ◽  
Mass Difference ◽  
Decisive Role ◽  
Mass Scale ◽  
Type I ◽  
Cp Asymmetry ◽  
Resonant Enhancement ◽  
Majorana Neutrinos ◽  
The Right ◽  
Decay Asymmetry

Vanilla leptogenesis within the type I seesaw framework requires the mass scale of the right-handed neutrinos to be above [Formula: see text] GeV. This lower bound can be avoided if at least two of the sterile states are almost mass degenerate, which leads to an enhancement of the decay asymmetry. Leptogenesis models that can be tested in current and upcoming experiments often rely on this resonant enhancement, and a systematic and consistent description is therefore necessary for phenomenological applications. In this paper, we give an overview of different methods that have been used to study the saturation of the resonant enhancement when the mass difference becomes comparable to the characteristic width of the Majorana neutrinos. In this limit, coherent flavor transitions start to play a decisive role, and off-diagonal correlations in flavor space have to be taken into account. We compare various formalisms that have been used to describe the resonant regime and discuss under which circumstances the resonant enhancement can be captured by simplified expressions for the CP asymmetry. Finally, we briefly review some of the phenomenological aspects of resonant leptogenesis.

scholarly journals A low-energy perspective on the minimal left-right symmetric model

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
W. Dekens ◽  
L. Andreoli ◽  
J. de Vries ◽  
E. Mereghetti ◽  
F. Oosterhof
Keyword(s):  
Dipole Moments ◽  
Global Analysis ◽  
Scalar Fields ◽  
Effective Field ◽  
Low Energy ◽  
Symmetric Model ◽  
Ckm Matrix ◽  
Stringent Constraint ◽  
The Standard Model ◽  
The Right

Abstract We perform a global analysis of the low-energy phenomenology of the minimal left-right symmetric model (mLRSM) with parity symmetry. We match the mLRSM to the Standard Model Effective Field Theory Lagrangian at the left-right-symmetry breaking scale and perform a comprehensive fit to low-energy data including mesonic, neutron, and nuclear β-decay processes, ∆F = 1 and ∆F = 2 CP-even and -odd processes in the bottom and strange sectors, and electric dipole moments (EDMs) of nucleons, nuclei, and atoms. We fit the Cabibbo-Kobayashi-Maskawa and mLRSM parameters simultaneously and determine a lower bound on the mass of the right-handed WR boson. In models where a Peccei-Quinn mechanism provides a solution to the strong CP problem, we obtain $$ {M}_{W_R} $$ M W R ≳ 5.5 TeV at 95% C.L. which can be significantly improved with next-generation EDM experiments. In the P-symmetric mLRSM without a Peccei-Quinn mechanism we obtain a more stringent constraint $$ {M}_{W_R} $$ M W R ≳ 17 TeV at 95% C.L., which is difficult to improve with low-energy measurements alone. In all cases, the additional scalar fields of the mLRSM are required to be a few times heavier than the right-handed gauge bosons. We consider a recent discrepancy in tests of first-row unitarity of the CKM matrix. We find that, while TeV-scale WR bosons can alleviate some of the tension found in the Vud,us determinations, a solution to the discrepancy is disfavored when taking into account other low-energy observables within the mLRSM.

scholarly journals A Review of CP Violation Measurements in Charm at LHCb

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1482
Author(s):  
Federico Betti
Keyword(s):  
Cp Violation ◽  
Precise Measurement ◽  
Mass Difference ◽  
Time Dependent ◽  
Charm Meson ◽  
Cp Asymmetry ◽  
Lhcb Experiment ◽  
Charm Hadron

The LHCb experiment has been able to collect the largest sample ever produced of charm-hadron decays, performing a number of measurements of observables related to CP violation in the charm sector. In this document, the most recent results from LHCb on the search of direct CP violation in D0→Ks0Ks0, D(s)+→h+π0 and D(s)+→h+η decays are summarised, in addition to the most precise measurement of time-dependent CP asymmetry in D0→h+h− decays and the first observation of mass difference between neutral charm-meson eigenstates.

THE ANALYSIS OF B→ηK* AND B→ϕKS DECAYS IN A FLAVOR CHANGING Z′ MODEL

2008 ◽  
Vol 23 (24) ◽  
pp. 4039-4049 ◽  
Author(s):  
SHUAI-WEI WANG ◽  
YAO-BEI LIU ◽  
HAI-ZHEN SONG
Keyword(s):  
Branching Ratios ◽  
Time Dependent ◽  
Tree Level ◽  
Neutral Currents ◽  
Parameter Region ◽  
Cp Asymmetry ◽  
Flavor Changing ◽  
The Right ◽  
Flavor Changing Neutral Currents

We study the large branching ratios of B→ηK* decays and the time-dependent CP asymmetry SϕKS anomaly of B→ϕKS decay in a flavor changing Z′ model associated with flavor changing neutral currents at the tree level. Considering the right-handed flavor changing couplings and setting ξLL = ξRL = ξLR = ξRR = ξ, we obtain 0.011 < ξ < 0.0131, this parameter region could give a simultaneous explanation to these anomalies of B→ηK* and B→ϕKS decays. The results are consistent with the constraints and the assumptions of some references.

NEUTRAL HIGGS AND CP VIOLATION

1991 ◽  
Vol 06 (18) ◽  
pp. 1693-1700 ◽  
Author(s):  
ANJAN S. JOSHIPURA
Keyword(s):  
Cp Violation ◽  
Mass Difference ◽  
Discrete Symmetry ◽  
Higgs Bosons ◽  
Neutral Currents ◽  
Flavor Changing ◽  
Flavor Changing Neutral Currents

An extended SU (2) × U (1) model with two-Higgs doublets and a discrete symmetry is considered. The latter is chosen to naturally obtain suppressed and hierarchical flavor-changing neutral currents induced by Higgs bosons. As a consequence, Higgs as light as 10 GeV is consistent with the observed KL – KS mass difference and problems with perturbative unitarity are avoided. In this model, the neutral Higgs can generate CP violation in K0 − K0 system and the consequences of a scheme where these exchanges provide the only source of CP violation are worked out.

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