Testing SUSY models of lepton flavor violation at a photon collider

The loop level lepton flavor violating signals $\gamma \gamma \to \ell \ell' (\ell=e,\mu,\tau, \ell \neq \ell^\prime)$ are studied in a scenario of low-energy, R-parity conserving, supersymmetric seesaw mechanism within the context of a high energy photon collider. Lepton flavor violation is due to off diagonal elements in the left s-lepton mass matrix induced by renormalization group equations. The average slepton masses ${\widetilde{m}}$ and the off diagonal matrix elements $\Delta m$ are treated as model independent free phenomenological parameters in order to discover regions in the parameter space where the signal cross section may be observable. At the energies of the $\gamma \gamma$ option of the future high-energy linear collider the signal has a potentially large standard model background, and therefore particular attention is paid to the study of kinematical cuts in order to reduce the latter at an acceptable level. We find, for the ($e\tau$) channel, non-negligible fractions of the parameter space ($\delta_{LL}=\Delta m^2/\widetilde{m}^2 \gtrsim 10^{-1}$) where the statistical significance ($SS$) is $SS \gtrsim 3$.Comment: 26 pages, 12 figures, Revtex

Decay of distance autocorrelation and Lyapunov exponents

This work presents numerical evidences that for discrete dynamical systems with one positive Lyapunov exponent the decay of the distance autocorrelation is always related to the Lyapunov exponent. Distinct decay laws for the distance autocorrelation are observed for different systems, namely exponential decays for the quadratic map, logarithmic for the H\'enon map and power-law for the conservative standard map. In all these cases the decay exponent is close to the positive Lyapunov exponent. For hyperbolic conservative systems, the power-law decay of the distance autocorrelation tends to be guided by the smallest Lyapunov exponent.Comment: 7 pages, 8 figure

Characterizing Weak Chaos using Time Series of Lyapunov Exponents

We investigate chaos in mixed-phase-space Hamiltonian systems using time series of the finite- time Lyapunov exponents. The methodology we propose uses the number of Lyapunov exponents close to zero to define regimes of ordered (stickiness), semi-ordered (or semi-chaotic), and strongly chaotic motion. The dynamics is then investigated looking at the consecutive time spent in each regime, the transition between different regimes, and the regions in the phase-space associated to them. Applying our methodology to a chain of coupled standard maps we obtain: (i) that it allows for an improved numerical characterization of stickiness in high-dimensional Hamiltonian systems, when compared to the previous analyses based on the distribution of recurrence times; (ii) that the transition probabilities between different regimes are determined by the phase-space volume associated to the corresponding regions; (iii) the dependence of the Lyapunov exponents with the coupling strength.Comment: 8 pages, 6 figure

Ocorrência e danos provocados por Hybolabus amazonicus Voss (Coleoptera: Attelabidae) em castanheira-do-brasil, em Rio Branco, Acre.

A castanheira-do-brasil, Bertholletia excelsa H.B.K., é uma espécie nativa da floresta Amazônica, tendo como valor econômico, em sua exploração extrativista, as amêndoas, ricas em proteínas que são utilizadas na alimentação humana, podendo também, na sua industrialização, serem obtidos óleos nobres utilizados na aviação e na fabricação de cosméticos. Além disso, sua madeira é de excelente qualidade, sendo que sua exploração atualmente é proibida por lei, devido ao grande número de árvores que vinham sendo abatidas para a indústria madeireira, ameaçando a espécie em extinção. É uma árvore que ocorre desde o Maranhão até 14 graus de latitude Sul, na mata alta de terra firme, com preferência para o solo argiloso ou argilo-silicoso. Ocorre na Venezuela, Colômbia, Peru, Bolívia e Guianas, mas no Brasil existe em maior número e formações compactas, nos estado do Pará, Amazonas, Acre, Maranhão, Mato Grosso, Rondônia, Amapá e Roraima (Muller, 1981). Segundo o Anuário Estatístico do Acre (1990), a produção de castanha foi de 17.497t, o que confere ao Acre lugar de destaque como explorador econômico dessa lecitidácea

Quantificação do carbono da biomassa microbiana do solo pelos métodos de espectrofotometria e titulometria.

JIPE 2013

Multiple Photonic Shells Around a Line Singularity

Line singularities including cosmic strings may be screened by photonic shells until they appear as a planar wall.Comment: 6 page

On the Levi-Civita solutions with cosmological constant

The main properties of the Levi-Civita solutions with the cosmological constant are studied. In particular, it is found that some of the solutions need to be extended beyond certain hypersurfaces in order to have geodesically complete spacetimes. Some extensions are considered and found to give rise to black hole structure but with plane symmetry. All the spacetimes that are not geodesically complete are Petrov type D, while in general the spacetimes are Petrov type I.Comment: Typed in Revtex, including two figures. To appear in Phys. Rev.