894 research outputs found
Phenomenology of CP Violation in a Flavor Blind MSSM and Beyond
We present an analysis of low energy CP violating observables in the Minimal
Supersymmetric Standard Model (MSSM). We focus on the predictions of CP
violation in b -> s transitions in the framework of a flavor blind MSSM, where
the CKM matrix remains the only source of flavor violation, but additional CP
violating phases are introduced in the soft SUSY breaking sector. We find large
and strongly correlated effects in Delta F = 0 observables like the electric
dipole moments (EDMs) of the electron and the neutron, as well as in Delta F =
1 observables like the time dependent CP asymmetries in B -> phi K_s and B ->
eta' K_s, the direct CP asymmetry in b -> s gamma and in several CP asymmetries
in B -> K* mu+ mu-. On the other hand, observables that are only sensitive to
CP violation in Delta F = 2 transitions, in particular the B_s mixing phase,
are found to be SM like in this framework. We stress that only in presence of
additional sources of flavor violation, sizeable New Physics effects to CP
violation in meson mixing can occur.Comment: 4 pages, 1 figure, submitted to the proceedings of the 17th
International Conference on Supersymmetry and the Unification of Fundamental
Interactions (SUSY 09), Boston, MA, June 5-10, 200
Searching for New Physics with Flavor Violating Observables
In this talk, I review the status and prospects of several low energy flavor
observables that are highly sensitive to New Physics effects. In particular I
discuss the implications for possible New Physics in b --> s transitions coming
from the recent experimental results on the B_s mixing phase, the branching
ratio of the rare decay B_s --> mu+mu-, and angular observables in the B --> K*
mu+mu- decay. Also the recent evidence for direct CP violation in singly
Cabibbo suppressed charm decays and its interpretation in the context of New
Physics models is briefly discussed.Comment: 8 pages, 2 figures, contribution to the proceedings of "Les
Rencontres de Physique de la Vallee d'Aoste", La Thuile, Italy, February 26 -
March 3, 201
New physics in transitions after LHC run 1
We present results of global fits of all relevant experimental data on rare
decays. We observe significant tensions between the Standard Model
predictions and the data. After critically reviewing the possible sources of
theoretical uncertainties, we find that within the Standard Model, the tensions
could be explained if there are unaccounted hadronic effects much larger than
our estimates. Assuming hadronic uncertainties are estimated in a sufficiently
conservative way, we discuss the implications of the experimental results on
new physics, both model independently as well as in the context of the minimal
supersymmetric standard model and models with flavour-changing bosons. We
discuss in detail the violation of lepton flavour universality as hinted by the
current data and make predictions for additional lepton flavour universality
tests that can be performed in the future. We find that the ratio of the
forward-backward asymmetries in and
at low dilepton invariant mass is a particularly sensitive probe of lepton
flavour universality and allows to distinguish between different new physics
scenarios that give the best description of the current data.Comment: 49 pages, 12 figures. v4: matches version published in EPJ
Fermion Hierarchy from Sfermion Anarchy
We present a framework to generate the hierarchical flavor structure of
Standard Model quarks and leptons from loops of superpartners. The simplest
model consists of the minimal supersymmetric standard model with tree level
Yukawa couplings for the third generation only and anarchic squark and slepton
mass matrices. Agreement with constraints from low energy flavor observables,
in particular Kaon mixing, is obtained for supersymmetric particles with masses
at the PeV scale or above. In our framework both the second and the first
generation fermion masses are generated at 1-loop. Despite this, a novel
mechanism generates a hierarchy among the first and second generations without
imposing a symmetry or small parameters. A second-to-first generation mass
ratio of order 100 is typical. The minimal supersymmetric standard model thus
includes all the necessary ingredients to realize a fermion spectrum that is
qualitatively similar to observation, with hierarchical masses and mixing. The
minimal framework produces only a few quantitative discrepancies with
observation, most notably the muon mass is too low. We discuss simple
modifications which resolve this and also investigate the compatibility of our
model with gauge and Yukawa coupling Unification.Comment: 42 pages, 11 figure
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