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## Electroweak precision constraints on the Lee-Wick standard model

Fonte: INT SCHOOL ADVANCED STUDIES
Publicador: INT SCHOOL ADVANCED STUDIES

Tipo: Artigo de Revista Científica

ENG

Relevância na Pesquisa

75.72%

#beyond standard model#quark masses and SM parameters#Higgs physics#standard model#INTERACTING HIGGS SECTOR#FIELD THEORY#S-MATRIX#INVARIANCE#UNITARITY#GRAVITY#Physics, Particles & Fields

We perform an analysis of the electroweak precision observables in the Lee-Wick Standard Model. The most stringent restrictions come from the S and T parameters that receive important tree level and one loop contributions. In general the model predicts a large positive S and a negative T. To reproduce the electroweak data, if all the Lee-Wick masses are of the same order, the Lee-Wick scale is of order 5 TeV. We show that it is possible to find some regions in the parameter space with a fermionic state as light as 2.4-3.5 TeV, at the price of rising all the other masses to be larger than 5-8 TeV. To obtain a light Higgs with such heavy resonances a fine-tuning of order a few per cent, at least, is needed. We also propose a simple extension of the model including a fourth generation of Standard Model fermions with their Lee-Wick partners. We show that in this case it is possible to pass the electroweak constraints with Lee-Wick fermionic masses of order 0.4-1.5 TeV and Lee-Wick gauge masses of order 3 TeV.

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## Linking natural supersymmetry to flavour physics

Fonte: Springer
Publicador: Springer

Tipo: Artigo de Revista Científica
Formato: 34

ENG

Relevância na Pesquisa

75.71%

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); With the aim of linking natural supersymmetry to flavour physics, a model is proposed based on a family symmetry G x U(1), where G is a discrete nonabelian subgroup of SU(2), with both F-term and (abelian) D-term supersymmetry breaking. A good fit to the fermion masses and mixing is obtained with the same U(1) charges for the left- and right- handed quarks of the first two families and the right-handed bottom quark, and with zero charge for the left-handed top-bottom doublet and the the right handed top. The model shows an interesting indirect correlation between the correct prediction for the V-ub/V-cb ratio and large right-handed rotations in the (s, b) sector, required to diagonalise the Yukawa matrix. For the squarks, one obtains almost degenerate first two generations. The main source of the FCNC and CP violation effects is the splitting between the first two families and the right-handed sbottom determined by the relative size of F-term and D-term supersymmetry breaking. The presence of the large right-handed rotation implies that the bounds on the masses of the first two families of squarks and the right handed sbottom are in a few to a few tens TeV range. The picture that emerges is light stops and left handed sbottom and much heavier other squarks.

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## Linking natural supersymmetry to flavour physics

Fonte: Springer
Publicador: Springer

Tipo: Artigo de Revista Científica
Formato: 34

ENG

Relevância na Pesquisa

75.71%

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); With the aim of linking natural supersymmetry to flavour physics, a model is proposed based on a family symmetry G xU(1), where G is a discrete nonabelian subgroup of SU(2), with both F-term and (abelian) D-term supersymmetry breaking. A good fit to the fermion masses and mixing is obtained with the same U(1) charges for the left- and right-handed quarks of the first two families and the right-handed bottom quark, and with zero charge for the left- handed top-bottom doublet and the the right handed top. The model shows an interesting indirect correlation between the correct prediction for the V-ub/V-cb ratio and large right-handed rotations in the (s,b) sector, required to diagonalise the Yukawa matrix. For the squarks, one obtains almost degenerate first two generations. The main source of the FCNC and CP violation effects is the splitting between the first two families and the right-handed sbottom determined by the relative size of F-term and D-term supersymmetry breaking. The presence of the large right-handed rotation implies that the bounds on the masses of the first two families of squarks and the right handed sbottom are in a few to a few tens TeV range. The picture that emerges is light stops and left handed sbottom and much heavier other squarks.

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## Sequestering CP Violation and GIM-Violation with Warped Extra Dimensions

Fonte: Institute of Physics
Publicador: Institute of Physics

Tipo: Artigo de Revista Científica

EN_US

Relevância na Pesquisa

75.57%

#CP violation#quark masses and SM parameters#technicolor and composite models#high energy physics#phenomenology of high energy physics

We propose a model of spontaneous CP violation to address the strong CP problem in warped extra dimensions that relies on sequestering flavor and CP violation. We assume that brane-localized Higgs Yukawa interactions respect a (U(3)) flavor symmetry that is broken only by bulk fermion mass and Yukawa terms. All CP violation arises from the vev of a CP-odd scalar field localized in the bulk. To suppress radiative corrections to (ar{ heta}), the doublet quarks in this model are localized on the IR brane. We calculate constraints from flavor-changing neutral currents (FCNCs), precision electroweak measurements, CKM unitarity, and the electric dipole moments in this model and predict (ar{ heta}) to be at least about (10^{−12}).; Physics

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## The kaon semileptonic form factor with near physical domain wall quarks

Fonte: Institute of Physics Publishing
Publicador: Institute of Physics Publishing

Tipo: Artigo de Revista Científica

Publicado em //2013
EN

Relevância na Pesquisa

65.57%

RBC/UKQCD collaboration, P.A. Boyle, J.M. Flynn, N. Garron, A. Jüttner, C.T. Sachrajda, K. Sivalingam, and J.M. Zanotti

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## Constraining a class of B-L extended models from vacuum stability and perturbativity

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

45.61%

The precise knowledge of the Standard Model Higgs boson and top quark masses
and couplings are crucial to understand the physics beyond it. SM like Higgs
boson having mass in the range of 123-127 GeV squeezes the parameters for
beyond standard model. In recent LHC era many TeV scale neutrino mass models
have earned much attention as they pose many interesting phenomenological
aspects. We have contemplated B-L extended models which are theoretically well
motivated and phenomenologically interesting, and successfully explain neutrino
mass generation. In this article we have analysed the detailed structures of
the scalar potentials for such models. We have computed the criteria which
guarantee that vacuum is bounded from below in all directions. Along with that
triviality and perturbativity bounds are also necessitated. Incorporating all
such effects we constrain the parameters of such models by performing their
renormalization group evolutions.; Comment: References added, version to appear in PRD

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## On the two-loop decoupling corrections to tau-lepton and b-quark running masses in the MSSM

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 23/12/2009

Relevância na Pesquisa

45.91%

Masses of heavy Standard Model fermions (top-quark, bottom-quark, and
tau-lepton) play an important role in the analysis of theories beyond the SM.
They serve as low-energy input and reduce the parameter space of such theories.
In this paper Minimal supersymmetric extension of the SM is considered and
two-loop relations between known SM values of fermion masses and running
parameters of the MSSM are studied within the effective theory approach. Both
b-quark and tau-lepton have the same quantum numbers with respect to SU(2)
groupand in the MSSM acquire their masses due to interactions with the same
Higgs doublet. As a consequence, for large values of tan beta parameter
corresponding Yukawa couplings also become large and together with tan beta can
significantly enhance radiative corrections. In the case of b-quark two-loop
O(alpha_s^2) contribution to the relation between running bottom-quark mass in
QCD and MSSM is known in literature. This paper is devoted to calculation of
the NNLO corrections proportional to Yukawa couplings. For the tau-lepton
obtained contribution can be considered as a good approximation to the full
two-loop result. For the b-quark numerical analysis given in the paper shows
that only the sum of strong and Yukawa corrections can play such a role.; Comment: 21 pages...

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## Fermion Masses and Anti-grand Unification

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 05/07/1996

Relevância na Pesquisa

45.76%

We present an extension of the Standard Model (SM) without supersymmetry,
which we use to calculate order of magnitude values for the elements of the
mass matrices in the SM. In our model we can fit the 9 quark and lepton masses
and 3 mixing angles using only 3 free parameters, with the overall mass scale
set by the electroweak interaction. The specific model described here has the
anti-grand unified gauge group SMG^3 x U(1)_f at high energies where SMG =
SU(3) x SU(2) x U(1) is the SM gauge group. The SM fermions are placed in
representations of the full gauge group so that they do not produce any
anomalies.It is pointed out that the same results can be obtained in an anomaly
free SMG x U(1)^3 model.; Comment: 15 page LaTeX file, uses FEYNMAN.tex; to be published in Physics
Letters B

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## Grand Unified Yukawa Matrix Ansatz: The Standard Model Fermion Mass, Quark Mixing and CP Violation Parameters

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

45.85%

We propose a new mass matrix ansatz: At the grand unified (GU) scale, the
standard model (SM) Yukawa coupling matrix elements are integer powers of the
square root of the GU gauge coupling constant \varepsilon \equiv
\sqrt{\alpha_{\text{GU}}}, multiplied by order unity random complex numbers. It
relates the hierarchy of the SM ermion masses and quark mixings to the gauge
coupling constants, greatly reducing the SM parameters, and can give good
fitting results of the SM fermion mass, quark mixing and CP violation
parameters. This is a neat but very effective ansatz.; Comment: 4 pages (two columns), by REVTeX 4, 2 tables, no figures, version for
publication in CPL

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## An Indirect Handle on the Down-Quark Yukawa Coupling

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 31/05/2014

Relevância na Pesquisa

45.7%

To measure the Yukawa couplings of the up and down quarks, Y_{u,d}, seems to
be far beyond the capabilities of current and (near) future experiments in
particle physics. By performing a general analysis of the potential
misalignment between quark masses and Yukawa couplings, we derive predictions
for the magnitude of induced flavor-changing neutral currents (FCNCs),
depending on the shift in the physical Yukawa coupling of first-generation
quarks. We find that a shift of -100% in the down-quark Yukawa Y_d would
generically result in ds transitions in conflict with Kaon physics. This could
already be seen as evidence for a non-vanishing direct coupling of the down
quark to the newly discovered Higgs boson. The non-observation of certain,
already well-constrained, processes is thus turned into a powerful indirect
measure of physical parameters of the effective Standard-Model, which are so
far basically unconstrained from experiment and extremely challenging to access
with other methods. In particular, we can already deduce that Y_d should vary
at most by ~50% from its Standard Model value, barring an alignment of new
physics effects with the SM Yukawa couplings. Such an (orthogonal) alignment
scenario is however in general much easier to test at the LHC. Similarly...

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## A Microscopic Approach to Quark and Lepton Masses and Mixings

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

45.81%

In recent papers a microscopic model for the SM Higgs mechanism has been
proposed, and an idea how to determine the 24 quark and lepton masses of all 3
generations has emerged in that framework. This idea is worked out in detail
here by accommodating the fermion masses and mixings to microscopic parameters.
The top quark mass can be given in terms of the Fermi scale and of certain
exchange couplings of isospin vectors obeying a tetrahedral symmetry. The
observed hierarchy in the family spectrum is attributed to a natural hierarchy
in the microscopic couplings. The neutrinos will be shown to vibrate within the
potential valleys of the system, thus retaining very tiny masses. This is
related to a Goldstone effect inside the internal dynamics. A discussion of the
quark and lepton mixing matrices is also included. The mixing angles of the
PMNS matrix are calculated for an example set of parameters, and a value for
the CP violating phase is given.; Comment: 37 pages, 4 figures, 2 tables

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## The New Minimal Supersymmetric GUT : Spectra, RG analysis and Fermion Fits

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

45.69%

The supersymmetric SO(10) GUT based on the ${\bf{210\oplus 10\oplus 120\oplus
126\oplus {\bar {126}}}}$ Higgs system provides a minimal framework for the
emergence of the R-parity exact MSSM at low energies and a viable
supersymmetric seesaw explanation for the observed neutrino masses and mixing
angles. We present formulae for MSSM decomposition of the superpotential
invariants, tree level light charged fermion effective Yukawa couplings,
Weinberg neutrino mass generation operator, and the $d=5,\Delta B=\Delta L \neq
0$ effective superpotential in terms of GUT parameters. We use them to
determine fits of the 18 available fermion mass-mixing data in terms of the
superpotential parameters of the NMSGUT and SUGRY(NUHM) type soft supersymmetry
breaking parameters ($\{m_{\tilde f},m_{1/2},A_0,M^2_{H,\bar H}\} $) specified
at the MSSM one loop unification scale $M_X^0=10^{16.33} $ GeV. Our fits are
compatible with electroweak symmetry breaking and Unification constraints and
yield right-handed neutrino masses in the leptogenesis relevant range :
$10^8-10^{13} $ GeV. Matching the SM data requires lowering the strange and
down quark Yukawas in the MSSM via large $\tan\beta$ driven threshold
corrections and characteristic soft Susy breaking spectra. The Susy spectra
have light pure Bino LSP...

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## Hierarchical Radiative Quark Mass Matrices with an $U(1)_X$ Horizontal Symmetry Model

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

45.85%

In a model with a gauge group $G_{SM}\otimes U(1)_X$, where $G_{SM} \equiv
SU(3)_C \otimes SU(2)_L \otimes U(1)_Y$ is the standard model gauge group and
$U(1)_X$ is a horizontal local gauge symmetry, we propose a radiative
generation of the spectrum of quark masses and mixing angles. The assignment of
horizontal charges is such that at tree level only the third family is massive.
Using these tree level masses and introducing exotic scalars, the light
families of quarks acquire hierarchical masses through radiative corrections.
The rank three quark mass matrices obtained are written in terms of a minimal
set of free parameters of the model, whose values are estimated performing a
numerical fit. The resulting quark masses and CKM mixing angles turn out to be
in good agreement with the experimental values.; Comment: 10 pages, 5 tables and 3 figures Some comments added to clarify as
suggested to publish. Some typing mistakes corrected. Update of Mass and CKM
matrix values

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## The Dualized Standard Model and its Applications

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 04/09/1998

Relevância na Pesquisa

45.63%

The Dualized Standard Model offers a natural explanation for Higgs fields and
3 generations of fermions plus a perturbative method for calculating SM
parameters. By adjusting only 3 parameters, 14 quark and lepton masses and
mixing parameters (including $\nu$ oscillations) are calculated with general
good success. Further predictions are obtained in post-GZK air showers and FCNC
decays.; Comment: Talk given at ICHEP98, Vancouver, 5 pages, Latex, 3 figures using
eps, uses ICHEP98 style file included

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## A Predictive SO(10) Scheme for Fermion Masses and Mixings

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 13/03/1995

Relevância na Pesquisa

45.71%

We present a predictive scheme for fermion masses and mixings inspired by
supersymmetric SO(10) in which the gauge hierarchy problem is resolved without
fine tuning the parameters. There are six predictions in the flavor sector, all
consistent with the present data. The scheme reproduces the familiar asymptotic
relations $m_b=m_\tau$ and $m_dm_sm_b=m_e m_\mu m_\tau$. A new expression for
$V_{cb}$ is obtained in terms of the quark masses. The remaining predictions
involve the quark mixing angles $V_{us}$ and $V_{ub}$, as well as the parameter
tan$\beta$ which turns out to be close to $m_t/m_b$.; Comment: 16 pages, plain LaTeX, 2 figures available on request

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## Exact One-Loop Evolution Invariants in the Standard Model

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 22/07/2010

Relevância na Pesquisa

45.76%

Guided by considerations of flavour symmetry, we construct a set of exact
Standard Model (SM) renormalisation group evolution invariants which link quark
masses and mixing parameters. We examine their phenomenological implications
and infer a simple combination of Yukawa coupling matrices which plays a unique
role in the SM, suggesting a possible new insight into the observed spectrum of
quark masses. Our evolution invariants are readily generalised to the leptons
in the case of Dirac neutrinos, but do not appear to be relevant for either
quarks or leptons in the MSSM.; Comment: 11 pages, 1 figure

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## Particle-Antiparticle Mixing, CP Violation and Rare K and B Decays in a Minimal Theory of Fermion Masses

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 23/01/2013

Relevância na Pesquisa

45.78%

We present a detailed study of Delta F=2 observables and of rare K^+(K_L) and
B_{s,d} meson decays in a "Minimal Theory of Fermion Masses" (MTFM). In this
theory Yukawa couplings are generated through the mixing with heavy vectorlike
(VF) fermions. This implies corrections to the SM quark couplings to W, Z and
Higgs so that FCNC processes receive contributions from tree level Z and Higgs
exchanges and W bosons couple to right-handed quarks. In a particular version
of this model in which the Yukawa matrix lambda^D in the heavy down fermion
sector is unitary, lambda^U =1 and M = M_{VF} is fixed, only three real and
positive definite parameters describe New Physics (NP) contributions to all
Delta F=2 and Delta F=1 observables in K and B_{s,d} systems once the known
quark masses and the CKM matrix are correctly reproduced. For M>1 TeV NP
contributions to B_{s,d}^0- bar{B}_{s,d}^0 mixings are found to be very small.
While in principle NP contributions to epsilon_K and Delta F=1 processes could
be large, the correlation between epsilon_K and K_L->mu^+ mu^- eliminates
basically NP contributions to epsilon_K and right-handed current contributions
to Delta F=1 FCNC observables. We find CMFV structure in B_{s,d} decays with
BR(B_{s,d}->mu^+ mu^-) uniquely enhanced for M=3 TeV by at least 35% and almost
up to a factor of two over their SM values. Also BR(K^+->pi^+ bar{nu} nu) and
BR(K_L->pi^0 bar{nu} nu)$ are uniquely enhanced by similar amount but the
correlation between them differs from the CMFV one. We emphasize various
correlations between K and B_{s...

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## Reappraisal of the limit on the variation in $\alpha$ implied by Oklo

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

45.64%

#Nuclear Theory#Astrophysics - Cosmology and Nongalactic Astrophysics#General Relativity and Quantum Cosmology

We reconsider the analysis of the sensitivity of neutron resonance energies
$E_i$ to changes in $\alpha$ with a view to resolving uncertainties that plague
earlier treatments. We point out that, with more appropriate choices of nuclear
parameters, the standard estimate (due to Damour and Dyson) of the sensitivity
for resonances in ${}^{150}$Sm is increased by a factor of 2.5. We go on to
identify and compute excitation, Coulomb and deformation corrections. To this
end, we use deformed Fermi density distributions fitted to the output of
Hartree-Fock (HF) + BCS calculations (with both the SLy4 and SkM$^*$ Skyrme
functionals), the energetics of the surface diffuseness of nuclei, and thermal
properties of their deformation. We also invoke the eigenstate thermalization
hypothesis, performing the requisite microcanonical averages with two
phenomenological level densities which, via the leptodermous expansion of the
level density parameter, include the effect of increased surface diffuseness.
Theoretical uncertainties are assessed with the \emph{inter-model} prescription
of Dobaczewski et al. [J. Phys. G: Nucl. Part. Phys. {\bf 41}, 074001 (2014)].
The corrections diminish the revised ${}^{150}$Sm sensitivity but not by more
than 25\%. Subject to a weak and testable restriction on the change in
$m_q/\Lambda$ (relative to the change in $\alpha$) since the time when the Oklo
reactors were active ($m_q$ is the average of the $\text{u}$ and $\text{d}$
current quark masses...

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## Dynamical Determination of the Top Quark and Higgs Masses and Fermion Masses in the Anti-Grand Unification Model

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 01/07/1997

Relevância na Pesquisa

45.86%

The multiple point criticality principle is applied to the pure Standard
Model (SM), with a desert up to the Planck scale. We are thereby led to impose
the constraint that the effective Higgs potential should have two degenerate
minima, one of which should have a vacuum expectation value of order unity in
Planck units. In this way we predict a top quark mass of $173 \pm 5$ GeV and a
Higgs particle mass of $135 \pm 9$ GeV. The quark and lepton mass matrices are
considered in the anti-grand unified extension of the SM based on the gauge
group $SMG^3 \otimes U(1)_f$; this group contains three copies of the SM gauge
group SMG, one for each generation, and an abelian flavour group $U(1)_f$. The
9 quark and lepton masses and 3 mixing angles are fitted using 3 free
parameters, with the overall mass scale set by the electroweak interaction. It
is pointed out that the same results can be obtained in an anomaly free $SMG
\otimes U(1)^3$ model.; Comment: uuencoded 4 page LaTeX file plus 2 postscript figures, uses
psfig.sty, epsfig.sty and stwol.sty; published in Proceedings of 28th
International Conference on High Energy Physics (ICHEP 96), Warsaw: 1127-1130

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## Linking natural supersymmetry to flavour physics

Fonte: Springer
Publicador: Springer

Tipo: Artigo de Revista Científica
Formato: 34

ENG

Relevância na Pesquisa

75.71%

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); With the aim of linking natural supersymmetry to flavour physics, a model is proposed based on a family symmetry G xU(1), where G is a discrete nonabelian subgroup of SU(2), with both F-term and (abelian) D-term supersymmetry breaking. A good fit to the fermion masses and mixing is obtained with the same U(1) charges for the left- and right-handed quarks of the first two families and the right-handed bottom quark, and with zero charge for the left- handed top-bottom doublet and the the right handed top. The model shows an interesting indirect correlation between the correct prediction for the V-ub/V-cb ratio and large right-handed rotations in the (s,b) sector, required to diagonalise the Yukawa matrix. For the squarks, one obtains almost degenerate first two generations. The main source of the FCNC and CP violation effects is the splitting between the first two families and the right-handed sbottom determined by the relative size of F-term and D-term supersymmetry breaking. The presence of the large right-handed rotation implies that the bounds on the masses of the first two families of squarks and the right handed sbottom are in a few to a few tens TeV range. The picture that emerges is light stops and left handed sbottom and much heavier other squarks.

Link permanente para citações: