319 research outputs found
Phases of N=1 supersymmetric chiral gauge theories
We analyze the phases of supersymmetric chiral gauge theories with an
antisymmetric tensor and (anti)fundamental flavors, in the presence of a
classically marginal superpotential deformation. Varying the number of flavors
that appear in the superpotential reveals rich infrared chiral dynamics and
novel dualities. The dualities are characterized by an infinite family of
magnetic duals with arbitrarily large gauge groups describing the same fixed
point, correlated with arbitrarily large classical global symmetries that are
truncated nonperturbatively. At the origin of moduli space, these theories
exhibit a phase with confinement and chiral symmetry breaking, an interacting
nonabelian Coulomb phase, and phases where an interacting sector coexists with
a sector that either s-confines or is in a free magnetic phase. Properties of
these intriguing "mixed phases" are studied in detail using duality and
a-maximization, and the presence of superpotential interactions provides
further insights into their formation.Comment: 35 pages, 5 figure
Soft Yukawa couplings in supersymmetric theories
The possibility of radiatively generated fermion masses arising from chiral
flavor violation in soft supersymmetry-breaking terms is explored. Vacuum
stability constraints are considered in various classes of models, and allow in
principle all of the first- and second-generation quarks and leptons and the
-quark to obtain masses radiatively. Radiatively induced Higgs-fermion
couplings have non-trivial momentum-dependent form factors, which at low
momentum are enhanced with respect to the case of tree-level Yukawa couplings.
These form factors may be probed by various sum rules and relations among Higgs
boson decay widths and branching ratios to fermion final states. An apparent,
large, hard violation of supersymmetry also results for Higgsino couplings.
Mixing between left- and right-handed scalar superpartners is enhanced. A
radiative muon mass is shown to lead to a relatively large and potentially
measurable contribution to the muon anomalous magnetic moment. If the
light-quark masses arise radiatively, the neutron electric dipole moment is
suppressed by a natural phase alignment between the masses and dipole moment,
and is below the current experimental bound. The possibility of neutrino masses
arising from softly broken lepton number, and concomitant enhanced
sneutrino-antisneutrino oscillations, is briefly discussed.Comment: 66 pages. LaTex + RevTex. 16 figures (included). Published version
(minor changes and typos corrected
Nonabelian Discrete Family Symmetry to Soften the SUSY Flavor Problem and to Suppress Proton Decay
Family symmetry could explain large mixing of the atmospheric neutrinos. The
same symmetry could explain why the flavor changing current processes in
supersymmetric standard models can be so suppressed. It also may be able to
explain why the proton is so stable. We investigate these questions in a
supersymmetric, renormalizable extension of the standard model, which possess a
family symmetry based on a binary dihedral group Q_6. We find that the
amplitude for \mu \to e+\gamma enjoys a suppression factor proportional to
|(V_{MNS})_{e3}| ~ m_e/(\sqrt{2}m_\mu) ~ 3.4\times 10^{-3}, and that B(p \to
K^0 \mu^+)/B(p \to K^0 e^+) ~ |(V_{MNS})_{e3}|^2 ~ 10^{-5}, where V_{MNS} is
the neutrino mixing matrix.Comment: 35 pages, 26 figure
A natural little hierarchy for RS from accidental SUSY
We use supersymmetry to address the little hierarchy problem in
Randall-Sundrum models by naturally generating a hierarchy between the IR scale
and the electroweak scale. Supersymmetry is broken on the UV brane which
triggers the stabilization of the warped extra dimension at an IR scale of
order 10 TeV. The Higgs and top quark live near the IR brane whereas light
fermion generations are localized towards the UV brane. Supersymmetry breaking
causes the first two sparticle generations to decouple, thereby avoiding the
supersymmetric flavour and CP problems, while an accidental R-symmetry protects
the gaugino mass. The resulting low-energy sparticle spectrum consists of
stops, gauginos and Higgsinos which are sufficient to stabilize the little
hierarchy between the IR scale and the electroweak scale. Finally, the
supersymmetric little hierarchy problem is ameliorated by introducing a singlet
Higgs field on the IR brane.Comment: 37 pages, 3 figures; v2: minor corrections, version published in JHE
Flavor Mediation Delivers Natural SUSY
If supersymmetry (SUSY) solves the hierarchy problem, then naturalness
considerations coupled with recent LHC bounds require non-trivial superpartner
flavor structures. Such "Natural SUSY" models exhibit a large mass hierarchy
between scalars of the third and first two generations as well as degeneracy
(or alignment) among the first two generations. In this work, we show how this
specific beyond the standard model (SM) flavor structure can be tied directly
to SM flavor via "Flavor Mediation". The SM contains an anomaly-free SU(3)
flavor symmetry, broken only by Yukawa couplings. By gauging this flavor
symmetry in addition to SM gauge symmetries, we can mediate SUSY breaking via
(Higgsed) gauge mediation. This automatically delivers a natural SUSY spectrum.
Third-generation scalar masses are suppressed due to the dominant breaking of
the flavor gauge symmetry in the top direction. More subtly, the
first-two-generation scalars remain highly degenerate due to a custodial U(2)
symmetry, where the SU(2) factor arises because SU(3) is rank two. This
custodial symmetry is broken only at order (m_c/m_t)^2. SUSY gauge coupling
unification predictions are preserved, since no new charged matter is
introduced, the SM gauge structure is unaltered, and the flavor symmetry treats
all matter multiplets equally. Moreover, the uniqueness of the anomaly-free
SU(3) flavor group makes possible a number of concrete predictions for the
superpartner spectrum.Comment: 17 pages, 7 figures, 2 tables. v2 references added, minor changes to
flavor constraints and a little discussion adde
Effect of the intermediate velocity emissions on the quasi-projectile properties for the Ar+Ni system at 95 A.MeV
The quasi-projectile (QP) properties are investigated in the Ar+Ni collisions
at 95 A.MeV taking into account the intermediate velocity emission. Indeed, in
this reaction, between 52 and 95 A.MeV bombarding energies, the number of
particles emitted in the intermediate velocity region is related to the overlap
volume between projectile and target. Mean transverse energies of these
particles are found particularly high. In this context, the mass of the QP
decreases linearly with the impact parameter from peripheral to central
collisions whereas its excitation energy increases up to 8 A.MeV. These results
are compared to previous analyses assuming a pure binary scenario
Pharmacological levels of withaferin A (Withania somnifera) trigger clinically relevant anticancer effects specific to triple negative breast cancer cells
Withaferin A (WA) isolated from Withania somnifera (Ashwagandha) has recently become an attractive phytochemical under investigation in various preclinical studies for treatment of different cancer types. In the present study, a comparative pathway-based transcriptome analysis was applied in epithelial-like MCF-7 and triple negative mesenchymal MDA-MB-231 breast cancer cells exposed to different concentrations of WA which can be detected systemically in in vivo experiments. Whereas WA treatment demonstrated attenuation of multiple cancer hallmarks, the withanolide analogue Withanone (WN) did not exert any of the described effects at comparable concentrations. Pathway enrichment analysis revealed that WA targets specific cancer processes related to cell death, cell cycle and proliferation, which could be functionally validated by flow cytometry and real-time cell proliferation assays. WA also strongly decreased MDA-MB-231 invasion as determined by single-cell collagen invasion assay. This was further supported by decreased gene expression of extracellular matrix-degrading proteases (uPA, PLAT, ADAM8), cell adhesion molecules (integrins, laminins), pro-inflammatory mediators of the metastasis-promoting tumor microenvironment (TNFSF12, IL6, ANGPTL2, CSF1R) and concomitant increased expression of the validated breast cancer metastasis suppressor gene (BRMS1). In line with the transcriptional changes, nanomolar concentrations of WA significantly decreased protein levels and corresponding activity of uPA in MDA-MB-231 cell supernatant, further supporting its anti-metastatic properties. Finally, hierarchical clustering analysis of 84 chromatin writer-reader-eraser enzymes revealed that WA treatment of invasive mesenchymal MDA-MB-231 cells reprogrammed their transcription levels more similarly towards the pattern observed in non-invasive MCF-7 cells. In conclusion, taking into account that sub-cytotoxic concentrations of WA target multiple metastatic effectors in therapy-resistant triple negative breast cancer, WA-based therapeutic strategies targeting the uPA pathway hold promise for further (pre)clinical development to defeat aggressive metastatic breast cancer
Hunting for Dynamical Supersymmetry Breaking in Theories That S-confine
The s-confining theories are a class of supersymmetric gauge theories with
infrared dynamics which are well-understood. Perturbing such theories can give
rise to dynamical supersymmetry breaking. We realize simple models of dynamical
supersymmetry breaking by perturbing two of the 10 SU(N) s-confining gauge
theories by a single trilinear operator. These examples have locally stable
vacua with spontaneous supersymmetry breaking. The first is SU(5) with two
generations (consisting of an antisymmetric tensor and an antifundamental) plus
two flavors. The second is SU(5) with three generations. The properties of the
former vacuum are calculable while those of the latter vacuum are not. We
briefly discuss the other SU(N) models.Comment: 21 pages, 1 figur
Ocular Application of the Kinin B1 Receptor Antagonist LF22-0542 Inhibits Retinal Inflammation and Oxidative Stress in Streptozotocin-Diabetic Rats
Purpose: Kinin B1 receptor (B1R) is upregulated in retina of Streptozotocin (STZ)-diabetic rats and contributes to vasodilation of retinal microvessels and breakdown of the blood-retinal barrier. Systemic treatment with B 1R antagonists reversed the increased retinal plasma extravasation in STZ rats. The present study aims at determining whether ocular application of a water soluble B1R antagonist could reverse diabetes-induced retinal inflammation and oxidative stress. Methods: Wistar rats were made diabetic with STZ (65 mg/kg, i.p.) and 7 days later, they received one eye drop application of LF22-0542 (1 % in saline) twice a day for a 7 day-period. The impact was determined on retinal vascular permeability (Evans blue exudation), leukostasis (leukocyte infiltration using Fluorescein-isothiocyanate (FITC)-coupled Concanavalin A lectin), retinal mRNA levels (by qRT-PCR) of inflammatory (B1R, iNOS, COX-2, ICAM-1, VEGF-A, VEGF receptor type 2, IL-1b and HIF-1a) and anti-inflammatory (B2R, eNOS) markers and retinal level of superoxide anion (dihydroethidium staining). Results: Retinal plasma extravasation, leukostasis and mRNA levels of B 1R, iNOS, COX-2, VEGF receptor type 2, IL-1b and HIF-1a were significantly increased in diabetic retinae compared to control rats. All these abnormalities were reversed to control values in diabetic rats treated with LF22-0542. B1R antagonist also significantly inhibited the increased production of superoxide anion in diabetic retinae. Conclusion: B1R displays a pathological role in the early stage of diabetes by increasing oxidative stress and proinflammator
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