156 research outputs found
Decay and Supersymmetry
The inclusive radiative -decay is a sensitive probe of new physics,
especially if related to the virtual exchange of a charged Higgs boson.
Supersymmetric models provide a particularly interesting example. In the limit
of exact supersymmetry, BR()~=~0, due to the vanishing of any
magnetic-moment transition operator. We illustrate the impact of this
constraint for realistic values of the supersymmetry-breaking parameters.Comment: 7 pages, CERN-TH.6830/93 (Minor changes; a comment on the case >1 has been added
On the Tuning Condition of Split Supersymmetry
Split Supersymmetry does not attempt to solve the hierarchy problem, but it
assumes a tuning condition for the electroweak scale. We clarify the meaning of
this condition and show how it is related to the underlying parameters. Simple
assumptions on the structure of the soft terms lead to predictions on tan beta
and on the physical Higgs mass.Comment: 9 pages, 6 figures, latex2
Multi-Messenger Theories of Gauge-Mediated Supersymmetry Breaking
We study gauge-mediated theories containing several messengers with the most
general SU(5)-invariant mass and supersymmetry-breaking parameters. We show
that these theories are predictive, containing only two relevant parameters
more than the minimal gauge-mediated model. Hypercharge D-terms can contribute
significantly to the right-handed charged sleptons and bring them closer in
mass to the left-handed sleptons. The messenger masses must be invariant under
either SU(5) or a ``messenger parity" to avoid spontaneous breaking of charge
conservation.Comment: 13 pages, 2 figure
Composite MFV and Beyond
We revisit and extend realizations of Minimal Flavor Violation (MFV) in
theories with strongly coupled electro-weak symmetry breaking. MFV requires
that some chiralities of light SM quarks are strongly composite leading,
depending on the scenario, to bounds from compositeness searches, precision
electro-weak tests or even flavor physics. Within the framework of partial
compositeness we show how to extend the MFV paradigm allowing the treat the top
quark differently. This can be realized if for example the strong sector has an
U(2) symmetry. In this case the light generations can be mostly elementary and
all the bounds are easily satisfied.Comment: 16 pages. v2) estimates improved, conclusions unchange
B-decay CP-asymmetries in SUSY with a U(2)^3 flavour symmetry
We study CP asymmetries in rare B decays within supersymmetry with a U(2)^3
flavour symmetry, motivated by the SUSY flavour and CP problems, the
hierarchies in the Yukawa couplings and the absence so far of any direct
evidence for SUSY. Even in the absence of flavour-blind phases, we find
potentially sizable CP violating contributions to b -> s decay amplitudes. The
effects in the mixing-induced CP asymmetries in B ->phi K(S) and B -> eta'
K(S), angular CP asymmetries in B -> K* mu+ mu- and the direct CP asymmetry in
B -> X(s) gamma can be in the region to be probed by LHCb and next generation B
factories. At the same time, these effects in B decays are compatible with CP
violating contributions to meson mixing, including a non-standard B(s) mixing
phase hinted by current tensions in the CKM fit mostly between S(psi K(S)),
epsilon(K) and Delta M(B(s))/Delta M(B(d)).Comment: 13 pages, 3 figure
Biology and Role of Extracellular Vesicles (EVs) in the Pathogenesis of Thrombosis
Extracellular vesicles (EVs) are well-established mediators of cell-to-cell communication. EVs can be released by every cell type and they can be classified into three major groups according to their biogenesis, dimension, density, and predominant protein markers: exosomes, microvesicles, and apoptotic bodies. During their formation, EVs associate with specific cargo from their parental cell that can include RNAs, free fatty acids, surface receptors, and proteins. The biological function of EVs is to maintain cellular and tissue homeostasis by transferring critical biological cargos to distal or neighboring recipient cells. On the other hand, their role in intercellular communication may also contribute to the pathogenesis of several diseases, including thrombosis. More recently, their physiological and biochemical properties have suggested their use as a therapeutic tool in tissue regeneration as well as a novel option for drug delivery. In this review, we will summarize the impact of EVs released from blood and vascular cells in arterial and venous thrombosis, describing the mechanisms by which EVs affect thrombosis and their potential clinical applications
Higgsinoless Supersymmetry and Hidden Gravity
We present a simple formulation of non-linear supersymmetry where superfields
and partnerless fields can coexist. Using this formalism, we propose a
supersymmetric Standard Model without the Higgsino as an effective model for
the TeV-scale supersymmetry breaking scenario. We also consider an application
of the Hidden Local Symmetry in non-linear supersymmetry, where we can
naturally incorporate a spin-two resonance into the theory in a manifestly
supersymmetric way. Possible signatures at the LHC experiments are discussed.Comment: 30 pages, 3 figures, references added, version to appear in JHE
Gluino Decays in Split Supersymmetry
We compute the gluino lifetime and branching ratios in Split Supersymmetry.
Using an effective-theory approach, we resum the large logarithmic corrections
controlled by the strong gauge coupling and the top Yukawa coupling. We find
that the resummation of the radiative corrections has a sizeable numerical
impact on the gluino decay width and branching ratios. Finally, we discuss the
gluino decays into gravitino, relevant in models with direct mediation of
supersymmetry breaking.Comment: 21 pages, 6 figure
Family Unification on an Orbifold
We construct a family-unified model on a Z_2xZ_2 orbifold in five dimensions.
The model is based on a supersymmetric SU(7) gauge theory. The gauge group is
broken by orbifold boundary conditions to a product of grand unified SU(5) and
SU(2)xU(1) flavor symmetry. The structure of Yukawa matrices is generated by an
interplay between spontaneous breaking of flavor symmetry and geometric factors
arising due to field localization in the extra dimension.Comment: 13 page
Strong, weak and flavor scalar triplets for the CDF Wjj anomaly
A model describing the 4.1\sigma\ Wjj anomaly observed by the CDF experiment
at the Tevatron collider is introduced. It features new scalar particles which
are charged both under the SU(3)_C and the SU(2)_L gauge groups and which
couple to pairs of quarks. We introduce several identical replicas of the
scalar multiplets in order to leave an unbroken U(3)_Q x U(3)_U x U(3)_D flavor
symmetry to satisfy the constraints coming from flavor physics. We discuss the
LHC reach on the new scalar resonances both in the resonant production channel
(with the Wjj final state) and in the QCD pair production channel (with the 4j
final state).Comment: 17 pages, 6 figures and 4 table
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