918 research outputs found
SUSY radiative corrections on mu-tau neutrino refraction including possible R-parity breaking interactions
In this paper we investigate the one-loop radiative corrections to the
neutrino indices of refraction from supersymmetric models. We consider the
Next-to Minimal Supersymmetric extension of the Standard Model (NMSSM) which
happens to be a better supersymmetric candidate than the MSSM for both
theoretical and experimental reasons. We scan the relevant SUSY parameters and
identify regions in the parameter space which yield interesting values for
V_{mu tau}. If R-parity is broken there are significant differences between
MSSM and NMSSM contributions contrary to the R-parity conserved case. Finally,
for a non-zero CP-violating phase, we show analytically that the presence of
V_{mu tau} will explicitly imply CP-violation effects on the supernova electron
(anti-) neutrino fluxes.Comment: 23 pages, 15 figures; v2: typos and 5 figures correcte
Possible CP-Violation effects in core-collapse Supernovae
We study CP-violation effects when neutrinos are present in dense matter,
such as outside the proto-neutron star formed in a core-collapse supernova.
Using general arguments based on the Standard Model, we confirm that there are
no CP-violating effects at the tree level on the electron neutrino and
anti-neutrino fluxes in a core-collapse supernova. On the other hand
significant effects can be obtained for muon and tau neutrinos even at the tree
level. We show that CP violating effects can be present in the supernova
electron (anti)neutrino fluxes as well, if muon and tau neutrinos have
different fluxes at the neutrinosphere. Such differences could arise due to
physics beyond the Standard Model, such as the presence of flavor-changing
interactions.Comment: 11 pages, 18 figure
Superspace WZW Models and Black Holes
We show how to write an off-shell action for the
supersymmetric WZW model in terms of chiral and twisted chiral
multiplets. We discuss the supersymmetry of this model and exhibit the
superconformal current algebra. Finally, we show that the off-shell
formulation makes it possible to perform a duality transformation, which leads
to a supersymmetric sigma model on a manifold with a black hole type
singularity.Comment: 12 page
Core-collapse supernova neutrinos and neutrino properties
Core-collapse supernovae are powerful neutrino sources. The observation of a
future (extra-)galactic supernova explosion or of the relic supernova neutrinos
might provide important information on the supernova dynamics, on the supernova
formation rate and on neutrino properties. One might learn more about unknown
neutrino properties either from indirect effects in the supernova (e.g. on the
explosion or on in the r-process) or from modifications of the neutrino time or
energy distributions in a detector on Earth. Here we will discuss in particular
possible effects of CP violation in the lepton sector. We will also mention the
interest of future neutrino-nucleus interaction measurements for the precise
knowledge of supernova neutrino detector response to electron neutrinos.Comment: 9 pages, 5 figures, Proceedings to "Three days of Strong Interactions
& Astrophysics HLPW08", 6-8 March 2008, SP
A dynamical collective calculation of supernova neutrino signals
We present the first calculations with three flavors of collective and shock
wave effects for neutrino propagation in core-collapse supernovae using
hydroynamical density profiles and the S matrix formalism. We explore the
interplay between the neutrino-neutrino interaction and the effects of multiple
resonances upon the time signal of positrons in supernova observatories. A
specific signature is found for the inverted hierarchy and a large third
neutrino mixing angle and we predict, in this case, a dearth of lower energy
positrons in Cherenkov detectors midway through the neutrino signal and the
simultaneous revelation of valuable information about the original fluxes. We
show that this feature is also observable with current generation neutrino
detectors at the level of several sigmas.Comment: 4 pages, 5 figure
Caracterização parcial e avaliação da maturidade de composto e biofertilizante para a aplicação em áreas de produção orgânica.
Este trabalho teve por objetivo acompanhar o desenvolvimento e a determinação da maturidade de compostos e biofertilizantes
Produção de toxinas inseticidas por isolados de Fusarlum spp. patogênicos a Dactylopius opuntiae Cockerel.
Neste trabalho buscou-se avaliar a produção de toxinas por seis isolados de Fusarium spp. obtidos em diferentes regiões do Agreste e Sertão pernambucano.Resumo 1733-2
Produção de mudas de palma-forrageira utilizando fragmentos de cladódios.
A palma (Opuntia ficus-indica L.) é uma das principais alternativas para alimentação de caprinos, ovinos e bovinos no Semiárido brasileiro. Contudo, o ataque da cochonilhado-carmim (Dactylopius opuntiae Cockerel) erradicou grande parte da área plantada, já que a maioria das variedades cultivadas são suscetíveis à praga. Três novas variedades resistentes à praga foram identificadas: Orelha-de-elefante mexicana, Miúda ou Doce e a variedade Mão-de-moça (clones IPA-Sertânea e PALMEPA-PB1). Contudo, a disponibilidade de material propagativo (cladódios ou raquetes) ainda é baixa, aumentando o preço da palma-semente. Assim, desenvolveu-se uma metodologia utilizando-se fragmentos (pedaços) de raquetes para a obtenção de novas mudas
Applications of the Ashtekar gravity to four dimensional hyperk\"ahler geometry and Yang-Mills Instantons
The Ashtekar-Mason-Newman equations are used to construct the hyperk\"ahler
metrics on four dimensional manifolds. These equations are closely related to
anti self-dual Yang-Mills equations of the infinite dimensional gauge Lie
algebras of all volume preserving vector fields. Several examples of
hyperk\"ahler metrics are presented through the reductions of anti self-dual
connections. For any gauge group anti self-dual connections on hyperk\"ahler
manifolds are constructed using the solutions of both Nahm and Laplace
equations.Comment: 9pages, Figures are not include
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