13 research outputs found
The Supersymmetric Origin of Matter
The Minimal Supersymmetric extension of the Standard Model (MSSM) can provide
the correct neutralino relic abundance and baryon number asymmetry of the
universe. Both may be efficiently generated in the presence of CP violating
phases, light charginos and neutralinos, and a light top squark. Due to the
coannihilation of the neutralino with the light stop, we find a large region of
parameter space in which the neutralino relic density is consistent with WMAP
and SDSS data. We perform a detailed study of the additional constraints
induced when CP violating phases, consistent with the ones required for
baryogenesis, are included. We explore the possible tests of this scenario from
present and future electron Electric Dipole Moment (EDM) measurements, direct
neutralino detection experiments, collider searches and the b -> s gamma decay
rate. We find that the EDM constraints are quite severe and that electron EDM
experiments, together with stop searches at the Tevatron and Higgs searches at
the LHC, will provide a definite test of our scenario of electroweak
baryogenesis in the next few years.Comment: 30 pages, 14 figure
Protective Effect of Chemically Characterized Polyphenol-Rich Fraction from Apteranthes europaea (Guss.) Murb. subsp. maroccana (Hook.f.) Plowes on Carbon Tetrachloride-Induced Liver Injury in Mice
Apteranthes europaea (Guss.) Murb. subsp. maroccana (Hook.f.) Plowes (A. europaea) is a medicinal plant widely used in traditional medicines to treat various diseases including hepatic pathogenesis. This study was conducted to evaluate the protective effect of chemically characterized polyphenol-rich fraction from A. europaea on carbon tetrachloride-induced liver injury in mice. The chemical characterization of A. europaea polyphenol-rich fraction was carried out using HPLC-DAD (high-performance liquid chromatography (HPLC) with a diode-array detector (DAD)). Carbon tetrachloride (CCl4) was used to induce liver injuries in mice as described in previous works. A polyphenol-rich fraction from A. europaea was used at a dose of 50 mg/Kg to study its hepatoprotective effect. Next, histopathological and biochemical alterations were investigated. The HPLC analysis revealed the presence of several phenolic compounds: gallic acid, methyl gallate, rutin, ferulic acid, and resorcinol. Regarding the mice treated with a polyphenol-rich fraction from A. europaea up to 50 mg/Kg and carbon tetrachloride, no significant biochemical nor histological alterations occurred in their liver; meanwhile, serious biochemical and histopathological changes were noted for liver recovered from the mice treated with carbon tetrachloride only. In conclusion, A. europaea extract is a promising source of hepatoprotective agents against toxic liver injury
Development of Bubble Chambers With Enhanced Stability and Sensitivity to Low-Energy Nuclear Recoils
The viability of using a Bubble Chamber for rare event searches and in
particular for the detection of dark matter particle candidates is considered.
Techniques leading to the deactivation of inhomogeneous nucleation centers and
subsequent enhanced stability in such a detector are described. Results from
prototype trials indicate that sensitivity to low-energy nuclear recoils like
those expected from Weakly Interacting Massive Particles can be obtained in
conditions of near total insensitivity to minimum ionizing backgrounds. An
understanding of the response of superheated heavy refrigerants to these
recoils is demonstrated within the context of existing theoretical models. We
comment on the prospects for the detection of supersymmetric dark matter
particles with a large chamber.Comment: 4 pages, 3 figures. Submitted to Phys. Rev. Let
First Dark Matter Limits from a Large-Mass, Low-Background Superheated Droplet Detector
We report on the fabrication aspects and calibration of the first large
active mass ( g) modules of SIMPLE, a search for particle dark matter
using Superheated Droplet Detectors (SDDs). While still limited by the
statistical uncertainty of the small data sample on hand, the first weeks of
operation in the new underground laboratory of Rustrel-Pays d'Apt already
provide a sensitivity to axially-coupled Weakly Interacting Massive Particles
(WIMPs) competitive with leading experiments, confirming SDDs as a convenient,
low-cost alternative for WIMP detection.Comment: Final version, Phys. Rev. Lett. (in press
Dark Matter Spin-Dependent Limits for WIMP Interactions on 19-F by PICASSO
The PICASSO experiment at SNOLAB reports new results for spin-dependent WIMP
interactions on F using the superheated droplet technique. A new
generation of detectors and new features which enable background discrimination
via the rejection of non-particle induced events are described. First results
are presented for a subset of two detectors with target masses of F of
65 g and 69 g respectively and a total exposure of 13.75 0.48 kgd. No
dark matter signal was found and for WIMP masses around 24 GeV/c new limits
have been obtained on the spin-dependent cross section on F of
= 13.9 pb (90% C.L.) which can be converted into cross section
limits on protons and neutrons of = 0.16 pb and = 2.60 pb
respectively (90% C.L). The obtained limits on protons restrict recent
interpretations of the DAMA/LIBRA annual modulations in terms of spin-dependent
interactions.Comment: Revised version, accepted for publication in Phys. Lett. B, 20 pages,
7 figure
Direct Detection of Dark Matter in Supersymmetric Models
We evaluate neutralino-nucleon scattering rates in several well-motivated
supersymmetric models, and compare against constraints on the neutralino relic
density, BF( b\to s\gamma ) as well as the muon anomalous magnetic moment a_\mu
. In the mSUGRA model, the indirect constraints favor the hyperbolic
branch/focus point (HB/FP) region of parameter space, and in fact this region
is just where neutralino-nucleon scattering rates are high enough to be
detected in direct dark matter search experiments! In Yukawa unified SUSY
SO(10) models with scalar mass non-universality, the relic density of
neutralinos is almost always above experimental bounds, while the corresponding
direct detection rates are below experimental levels. Conversely, in five
dimensional SO(10) models where gauge symmetry breaking is the result of
compactification of the extra dimension, and supersymmetry breaking is
communicated via gaugino mediation, the relic density is quite low, while
direct detection rates can be substantial.Comment: 25 page latex file including 18 EPS figures; revised version with
references added and cross sections rescaled; figures changed. A copy of the
paper with better resolution figures can be found at
http://www.hep.fsu.edu/~belyaev/projects/directz1
Antioxidant, Anti-Inflammatory and Antidiabetic Proprieties of LC-MS/MS Identified Polyphenols from Coriander Seeds
Coriandrum sativum L. seeds are traditionally used to treat diabetes and its complications (inflammation and formation of reactive oxygen species) around the world. The present study investigates the antidiabetic, anti-inflammatory, and antioxidant effects of the polyphenol fraction of Coriandrum sativum seeds (PCS). Diabetic mice were orally administered with PCS (25 and 50 mg/kg b.w.) for 28 days. Oral glucose tolerance (OGTT) was also evaluated along with the anti-inflammatory effect, assessed by measuring paw edema development induced with carrageenan in Wistar rat and the antioxidant activity assessed using two tests (β-carotene discoloration and DPPH). Treatment of diabetic mice with PCS for four weeks managed their high fasting blood glucose levels, improved their overall health, also revealed an excellent antihyperlipidemic activity. The OGTT result showed a potent antihyperglycemic activity, and following the anti-inflammatory and antioxidant effects, the PCS exhibited a perfect activity. LC-MS/MS result revealed the presence of 9 polyphenols. This modest work indicates that the PCS have an important antidiabetic, antihyperglycemic, antihyperlipidemic, anti-inflammatory, and antioxidant effect that can be well established treatment of diabetes and its complications