2,178 research outputs found
B Physics: CP Violation Beyond the SM
We analyse the present experimental evidence for a complex CKM matrix, even
allowing for New Physics contributions to , %,
, , and the piece of and . We emphasize the crucial r\^{o}le played by
the angle in both providing irrefutable evidence for a 33
complex CKM matrix and placing constraints on the size of NP contributions. It
is shown that even if one allows for New Physics a real CKM matrix is excluded
at a 99.92% C.L., and the probability for the phase to be in the
interval is
99.7%. Large value of the phase , e.g. of order , is only
possible in models where the unitarity of the
Cabibbo-Kobayashi-Maskawa matrix is violated through the introduction of extra
quarks. We study the allowed range for and the effect of a
large on various low-energy observables, such as CP asymmetries in
meson decays. We also discuss the correlated effects which would be observable
at high energy colliders, like decays , etc..Comment: 14 pages, 7 figures. Presented at the Symposium in Honour of Gustavo
C. Branco "CP Violation and the Flavour Puzzle", Lisbon, Portugal, 19-20 July
2005. To appear in Acta Physica Polonica
Coexistence of periods in a bisecting bifurcation
The inner structure of the attractor appearing when the
Varley-Gradwell-Hassell population model bifurcates from regular to chaotic
behaviour is studied. By algebraic and geometric arguments the coexistence of a
continuum of neutrally stable limit cycles with different periods in the
attractor is explained.Comment: 13 pages, 5 figure
A Novel Kind of Neutrino Oscillation Experiment
A novel method to look for neutrino oscillations is proposed based on the
elastic scattering process , taking advantage of the dynamical zero present in the differential
cross section for . An
effective tunable experiment between the "appearance" and "disappearance"
limits is made possible. Prospects to exclude the allowed region for
atmospheric neutrino oscillations are given.Comment: 11 pages (+3 figures, available upon request),Standard Latex,
FTUV/94-3
Bifurcations in the Lozi map
We study the presence in the Lozi map of a type of abrupt order-to-order and
order-to-chaos transitions which are mediated by an attractor made of a
continuum of neutrally stable limit cycles, all with the same period.Comment: 17 pages, 12 figure
Invariant approach to flavour-dependent CP-violating phases in the MSSM
We use a new weak basis invariant approach to classify all the observable
phases in any extension of the Standard Model (SM). We apply this formalism to
determine the invariant CP phases in a simplified version of the Minimal
Supersymmetric SM with only three non-trivial flavour structures. We propose
four experimental measures to fix completely all the observable phases in the
model. After these phases have been determined from experiment, we are able to
make predictions on any other CP-violating observable in the theory, much in
the same way as in the Standard Model all CP-violation observables are
proportional to the Jarlskog invariant.Comment: 25 pages, 12 figure
Vacuum Induced CP Violation Generating a Complex CKM Matrix with Controlled Scalar FCNC
We propose a viable minimal model with spontaneous CP violation in the
framework of a Two Higgs Doublet Model. The model is based on a generalised
Branco-Grimus-Lavoura model with a flavoured symmetry, under
which two of the quark families are even and the third one is odd. The
lagrangian respects CP invariance, but the vacuum has a CP violating phase,
which is able to generate a complex CKM matrix, with the rephasing invariant
strength of CP violation compatible with experiment. The question of scalar
mediated flavour changing neutral couplings is carefully studied. In particular
we point out a deep connection between the generation of a complex CKM matrix
from a vacuum phase and the appearance of scalar FCNC. The scalar sector is
presented in detail, showing that the new scalars are necessarily lighter than
1 TeV. A complete analysis of the model including the most relevant constraints
is performed, showing that it is viable and that it has definite implications
for the observation of New Physics signals in, for example, flavour changing
Higgs decays or the discovery of the new scalars at the LHC. We give special
emphasis to processes like , as well as , which are relevant for the LHC and the ILC.Comment: 36 pages, 11 figure
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