1,065 research outputs found
Direct Detection of Electroweak-Interacting Dark Matter
Assuming that the lightest neutral component in an SU(2)L gauge multiplet is
the main ingredient of dark matter in the universe, we calculate the elastic
scattering cross section of the dark matter with nucleon, which is an important
quantity for the direct detection experiments. When the dark matter is a real
scalar or a Majorana fermion which has only electroweak gauge interactions, the
scattering with quarks and gluon are induced through one- and two-loop quantum
processes, respectively, and both of them give rise to comparable contributions
to the elastic scattering cross section. We evaluate all of the contributions
at the leading order and find that there is an accidental cancellation among
them. As a result, the spin-independent cross section is found to be
O(10^-(46-48)) cm^2, which is far below the current experimental bounds.Comment: 19 pages, 7 figures, published versio
Slepton Oscillation at Large Hadron Collider
Measurement of Lepton-Flavor Violation (LFV) in the minimal SUSY Standard
Model (MSSM) at Large Hadron Collider (LHC) is studied based on a realistic
simulation. We consider the LFV decay of the second-lightest neutralino,
, in the case
where the flavor mixing exists in the right-handed sleptons. We scan the
parameter space of the minimal supergravity model (MSUGRA) and a more generic
model in which we take the Higgsino mass as a free parameter. We find
that the possibility of observing LFV at LHC is higher if is smaller than
the MSUGRA prediction; the LFV search at LHC can cover the parameter range
where the decay can be suppressed by the cancellation among
the diagrams for this case.Comment: 29 pages, 10 figure
Elaboração de silagem ácida de vísceras de surubin (Pseudoplatystoma sp.).
bitstream/item/62557/1/CT201118-1.pd
Search for neutrinoless tau decays tau -> 3l and tau -> l K0S
Neutrinoless tau-lepton decays into either three leptons (tau- -> l1- l2 l3)
or one lepton and one K0S meson(tau- -> l- K0S) where lepton l means either an
electron or muon, have been searched for using 48.6 fb^{-1} of data collected
with the Belle detector at the KEKB e+e- collider. No evidence for candidate
decays are found in any channel. Therefore we set 90% confidence level upper
limits on the branching fraction for 8 different decay modes. These limits are
more stringent than those set previously and reach to the 10^{-7} level.Comment: Invited talk at the Seventh International Workshop on Tau Lepton
Physics (TAU02), Santa Cruz, Ca, USA, Sept 2002, 7 pages, LaTeX, 3 eps
figure
Democratic (S)fermions and Lepton Flavor Violation
The democratic approach to account for fermion masses and mixing is known to
be successful not only in the quark sector but also in the lepton sector. Here
we extend this ansatz to supersymmetric standard models, in which the K\"ahler
potential obeys underlying S_3 flavor symmetries. The requirement of neutrino
bi-large mixing angles constrains the form of the K\"ahler potential for
left-handed lepton multiplets. We find that right-handed sleptons can have
non-degenerate masses and flavor mixing, while left-handed sleptons are argued
to have universal and hence flavor-blind masses. This mass pattern is testable
in future collider experiments when superparticle masses will be measured
precisely. Lepton flavor violation arises in this scenario. In particular, \mu
\to e \gamma is expected to be observed in a planning future experiment if
supersymmetry breaking scale is close to the weak scale.Comment: 22 pages, 2 figure
Scenery from the Top: Study of the Third Generation Squarks at CERN LHC
In the minimal supersymmetric standard model (MSSM) properties of the third
generation sfermions are important from the viewpoint of discriminating the
SUSY breaking models and in the determination of the Higgs boson mass. If
gluinos are copiously produced at CERN LHC, gluino decays into tb through stop
and sbottom can be studied using hadronic decays of the top quark. The
kinematical endpoint of the gluino decays can be evaluated using a W sideband
method to estimate combinatorial backgrounds. This implies that fundamental
parameters related to the third generation squarks can be reliably measured.
The top-quark polarization dependence in the decay process may also be
extracted by looking at the b jet distribution near the kinematical endpoint.Comment: 4 pages in PRL format, 4 Postscript figures, uses revtex
On suppressing the Higgsino-mediated proton decay in SUSY SO(10) GUT's
Using the freedom in SO(10) GUT's one can generalize the existing models
without changing the mass spectrum of fermions to obtain a significant
suppression of proton decay resulting from the baryon number violating
operators of dimension 5. In some limiting cases, their contributions can be
made negligible compared to the dimension 6 operators resulting from the heavy
gauge bosons exchange.Comment: 19 pages, 3 Postscript figures, 2 mpost figures, rearranged plots,
corrected typo
Neutrinoless Double Beta Decay in Supersymmetric Seesaw model
Inspired by the recent HEIDELBERG-MOSCOW double beta decay experiment, we
discuss the neutrinoless double beta decay in the supersymmetric seesaw model.
Our numerical analysis indicates that we can naturally explain the data of the
observed neutrinoless double beta decay, as well as that of the solar and
atmospheric neutrino experiments with at least one Majorana-like sneutrino of
middle energy scale in the model.Comment: latex, 25 pages, include 5 figures, final version in Phys. Rev.
Parede celular de levedura em rações para alevinos de Tilápia do Nilo.
Este estudo avaliou a suplementação de diferentes níveis de parede celular de levedura spray dried (0,0%; 0,1%; 0,2% e 0,4%), em rações para alevinos de tilápia do Nilo. Foram utilizados 120 alevinos revertidos sexualmente para macho, com peso médio inicial de 2,48 ± 0,07 g, distribuídos aleatoriamente em 20 aquários circulares com volume de 60 L (seis peixes por aquário), dotados de sistema de recirculação de água com biofiltro e aquecimento controlado. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos e cinco repetições. Não houve diferença significativa para conversão alimentar, taxa de crescimento específico e taxa de eficiência protéica. Para o ganho de peso houve efeito quadrático (p<0,05), com nível ótimo estimado em 0,22% de parede celular. Pode-se concluir que a inclusão de 0,22% de parede celular de levedura proporciona melhores resultados de desempenho produtivo para alevinos de tilápia do Nilo. Termos para indexação: Saccharomyces sp., glucano, manano,bitstream/item/38744/1/BP200847.pdfDocumento on-line
- …