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 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.

LIGHT TOP QUARK AND LIGHT CHARGED HIGGS REVISITED

1991 ◽  
Vol 06 (37) ◽  
pp. 3375-3383 ◽  
Author(s):  
ANJAN S. JOSHIPURA ◽  
SAURABH D. RINDANI
Keyword(s):  
Top Quark ◽  
Vacuum Expectation ◽  
Scalar Fields ◽  
Discrete Symmetry ◽  
Higgs Bosons ◽  
Expectation Values ◽  
Flavor Changing ◽  
Wide Range ◽  
Down Quark ◽  
Charged Higgs

A model with two Higgs doublets is presented where a discrete symmetry is imposed so that the flavor-changing neutral currents in the down-quark sector are naturally suppressed and obey a hierarchy determined by the hierarchy of the Kobayashi-Maskawa matrix elements. The fermion couplings to charged-Higgs bosons are different from those in models with natural flavor conservation. As a consequence, it is possible to have a light top quark which evades the Tevatron limit by decaying predominantly into a light charged Higgs with mass M H ≤ mt - mb. The model is also consistent with data on ε and [Formula: see text] mixing for a wide range of M H and the ratio of vacuum expectation values of the scalar fields.

SPONTANEOUS CP VIOLATION IN A TWO GENERATION SU(2)L × SU(2)R × U(1)B − L × U(1)H MODEL

1993 ◽  
Vol 08 (12) ◽  
pp. 2119-2133
Author(s):  
SASWATI SARKAR ◽  
ASIM K. RAY ◽  
AMBAR GHOSAL ◽  
DEBASIS BHOWMICK ◽  
KRISHNANATH BANDYOPADHYAY
Keyword(s):  
Cp Violation ◽  
Quantum Number ◽  
Mass Difference ◽  
Suitable Choice ◽  
Tree Level ◽  
Model Parameters ◽  
Experimental Values

It is shown that spontaneous CP violation can occur in a two generation left–right symmetric horizontal model if there are two Higgs bi-doublets with the same horizontal hypercharge quantum number. The contributions to the KL − KS mass difference (Δm) and CP violating effects (∊, ∊′/∊, Dn) to the box and tree level diagrams are discussed to demonstrate that the experimental values of Δm and ∊ can be explained with suitable choice of the model parameters.

CP-VIOLATION IN A LEFT-RIGHT SYMMETRIC HORIZONTAL FLAVOUR CHIRAL MODEL

1988 ◽  
Vol 03 (06) ◽  
pp. 607-614 ◽  
Author(s):  
KRISHNANATH BANDYOPADHYAY ◽  
ASIM K. RAY ◽  
AMITAVA RAYCHAUDHURI
Keyword(s):  
Cp Violation ◽  
Gauge Boson ◽  
Relative Phase ◽  
Vacuum Expectation ◽  
Chiral Model ◽  
Expectation Values ◽  
Higgs Vacuum ◽  
Boson Exchange ◽  
Text Model ◽  
Left And Right

A horizontal symmetric [Formula: see text] model is studied in the light of spontaneous CP-violation. The left- and right-handed Kobayashi-Maskawa matrices are real and the CP-nonconservation occurs through horizontal gauge boson exchange. To be in accord with experiment, the relative phase between two Higgs vacuum expectation values must be rather small.

scholarly journals Minimal scoto-seesaw mechanism with spontaneous CP violation

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
D. M. Barreiros ◽  
F. R. Joaquim ◽  
R. Srivastava ◽  
J. W. F. Valle
Keyword(s):  
Dark Matter ◽  
Cp Violation ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Discrete Symmetry ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Seesaw Mechanism ◽  
Cosmological Observations ◽  
Scalar Singlet

Abstract We propose simple scoto-seesaw models to account for dark matter and neutrino masses with spontaneous CP violation. This is achieved with a single horizontal $$ {\mathcal{Z}}_8 $$ Z 8 discrete symmetry, broken to a residual $$ {\mathcal{Z}}_2 $$ Z 2 subgroup responsible for stabilizing dark matter. CP is broken spontaneously via the complex vacuum expectation value of a scalar singlet, inducing leptonic CP-violating effects. We find that the imposed $$ {\mathcal{Z}}_8 $$ Z 8 symmetry pushes the values of the Dirac CP phase and the lightest neutrino mass to ranges already probed by ongoing experiments, so that normal-ordered neutrino masses can be cornered by cosmological observations and neutrinoless double beta decay experiments.

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 Neutrino mixing with nonzero θ13 and CP violation in the 3-3-1 model based on S4 flavor symmetry

2015 ◽  
Vol 30 (17) ◽  
pp. 1550102 ◽  
Author(s):  
Vo Van Vien ◽  
Hoang Ngoc Long ◽  
Dinh Phan Khoi
Keyword(s):  
Cp Violation ◽  
Discrete Symmetry ◽  
Double Beta Decay ◽  
Tree Level ◽  
Neutrino Mixing ◽  
Quark Masses ◽  
Neutrino Sector ◽  
New Feature ◽  
Normal Spectrum ◽  
New Formula

The 3-3-1 model proposed in 2011 based on discrete symmetry [Formula: see text] responsible for the neutrino and quark masses is updated, in which the nonzero [Formula: see text] is focused. Neutrino masses and mixings are consistent with the most recent data on neutrino oscillations without perturbation. The new feature is adding a new [Formula: see text] anti-sextet lying in doublet under [Formula: see text] which can result the nonzero [Formula: see text] without perturbation, and consequently, the number of Higgs multiplets required is less than those of other models based on non-Abelian discrete symmetries and the 3-3-1 models. The exact tribimaximal form obtained with the breaking [Formula: see text] in charged lepton sector and [Formula: see text] in neutrino sector. If both breakings [Formula: see text] and [Formula: see text] are taken place in neutrino sector, the realistic neutrino spectrum is obtained without perturbation. The upper bound on neutrino mass and the effective mass governing neutrinoless double beta decay at the tree level are presented. The model predicts the Dirac CP violation phase [Formula: see text] in the normal spectrum (with [Formula: see text]) and [Formula: see text] in the inverted spectrum.

scholarly journals (g − 2)μ versus K → π + Emiss induced by the (B − L)23 boson

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Zhaofeng Kang ◽  
Yoshihiro Shigekami
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Neutral Current ◽  
Tree Level ◽  
Meson Decays ◽  
Loop Level ◽  
Flavor Changing ◽  
The Standard Model ◽  
Flavor Changing Neutral Current

Abstract To address the long-standing (g − 2)μ anomaly via a light boson, in ref. [1] we proposed to extend the standard model (SM) by the local (B − L)23, under which only the second and third generations of fermions are charged. It predicts an invisible Z′ with mass $$ \mathcal{O}(100) $$ O 100 MeV, and moreover it has flavor-changing neutral current (FCNC) couplings to the up-type quarks at tree level. Such a Z′, via KL→ π0 + Z′(→$$ v\overline{v} $$ v v ¯ ) at loop level, may be a natural candidate to account for the recent KOTO anomaly. In this article, we investigate this possibility, to find that Z′ can readily do this job if it is no longer responsible for the (g − 2)μ anomaly. We further find that both anomalies can be explained with moderate tuning of the CP violation, but may contradict the B meson decays.

scholarly journals Exploring multi-Higgs models with softly broken large discrete symmetry groups

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Ivo de Medeiros Varzielas ◽  
Igor P. Ivanov ◽  
Miguel Levy
Keyword(s):  
General Procedure ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Discrete Symmetry ◽  
Higgs Doublet ◽  
Structural Features ◽  
Symmetry Groups ◽  
Symmetric Model ◽  
Exact Symmetry ◽  
Symmetric Vacuum

AbstractWe develop methods to study the scalar sector of multi-Higgs models with large discrete symmetry groups that are softly broken. While in the exact symmetry limit, the model has very few parameters and can be studied analytically, proliferation of quadratic couplings in the most general softly broken case makes the analysis cumbersome. We identify two sets of soft breaking terms which play different roles: those which preserve the symmetric vacuum expectation value alignment, and the remaining terms which shift it. Focusing on alignment preserving terms, we check which structural features of the symmetric parent model are conserved and which are modified. We find remarkable examples of structural features which are inherited from the parent symmetric model and which persist even when no exact symmetry is left. The general procedure is illustrated with the example of the three-Higgs-doublet model with the softly broken symmetry group $$\Sigma (36)$$ Σ ( 36 ) .

UPDATED BOUNDS ON HIGGS TRIPLET VACUUM EXPECTATION VALUES AND THE TREE-LEVEL ρ PARAMETER FROM RADIATIVE CORRECTIONS

1991 ◽  
Vol 06 (21) ◽  
pp. 1961-1966 ◽  
Author(s):  
THOMAS G. RIZZO
Keyword(s):  
Parity Violation ◽  
Top Quark ◽  
Input Data ◽  
Vacuum Expectation ◽  
Top Quarks ◽  
Higgs Bosons ◽  
Tree Level ◽  
Radiative Corrections ◽  
Expectation Values ◽  
Upper Limits

We obtain 95% C. L. upper limits on the ratio of triplet to doublet vacuum expectation values in two extended electroweak models from radiative corrections. We use as input data from LEP, the Tevatron, the CERN [Formula: see text] colliders, and various low-energy experiments such as atomic parity-violation and deep inelastic scattering. The analysis includes the incorporation of leading two-loop electroweak contributions to ∆r and ρ arising from heavy top quarks and Higgs bosons, the Consoli–Hollik–Jegerlehner resummation technique, and QCD corrections to the hadronic partial widths of the Z using the new value for the (αs/π)3 coefficient. Our limits are found to be only mildly sensitive to the top quark and Higgs boson masses and somewhat stronger than those obtained previously. Our results are then generalized to bounds on the allowed value of the tree-level ρ parameter.

Sign in / Sign up

Export Citation Format

Share Document