Constraining the absolute neutrino mass scale and Majorana CP violating phases by future 0νββ decay experiments

Assuming that neutrinos are Majorana particles, in a three-generation framework, current and future neutrino oscillation experiments can determine six out of the nine parameters which fully describe the structure of the neutrino mass matrix. We try to clarify the interplay among the remaining parameters, the absolute neutrino mass scale and two CP violating Majorana phases, and how they can be accessed by future neutrinoless double beta (0vυββ) decay experiments, for the normal as well as for the inverted order of the neutrino mass spectrum. Assuming the oscillation parameters to be in the range presently allowed by atmospheric, solar, reactor, and accelerator neutrino experiments, we quantitatively estimate the bounds on m 0, the lightest neutrino mass, that can be inferred if the next generation 0υββ decay experiments can probe the effective Majorana mass (m ee) down to ∼1 meV. In this context we conclude that in the case that neutrinos are Majorana particles, (a) if m 0≳300 meV, i.e., within the range directly attainable by future laboratory experiments as well as astrophysical observations, then m ee≳30 meV must be observed, (b) if m 0 ≤ 300 meV, results from future 0υββ decay experiments combined with stringent bounds on the neutrino oscillation parameters, especially the solar ones, will place much stronger limits on the allowed values of m 0 than these direct experiments. For instance, if a positive signal is observed around m ee = 10 meV, we estimate 3≲m 0/meV≲65 at 95% C.L.; on the other hand, if no signal is observed down to m ee = 10 meV, then m 0≲55 meV at 95% C.L.

Quartic anomalous couplings in eγ colliders

We study the production of gauge-boson pairs at the next generation of linear e+e- colliders operating in the eγ mode. The processes eγ → VV′F (V,V′ = W,Z, or γ and F = e or ν) can give valuable information on possible deviations of the quartic vector-boson couplings from the Standard Model predictions. We establish the range of the new couplings that can be explored in these colliders based on a 3σ effect in the total cross section. We also present several kinematical distributions of the final state particles that could manifest the underlying new dynamics. Our results show that an eγ collider can extend considerably the bounds on anomalous interactions coming from oblique radiative corrections and from direct searches in e+e- colliders.

NASH game and mixed H2/H∞ control

In this work a Nonzero-Sum NASH game related to the H2 and H∞ control problems is formulated in the context of convex optimization theory. The variables of the game are limiting bounds for the H2 and H∞ norms, and the final controller is obtained as an equilibrium solution, which minimizes the `sensitivity of each norm' with respect to the other. The state feedback problem is considered and illustrated by numerical examples.

Neutrino mixing effects on the tau-neutrino mass limit

We point out that the usual experimental upper bounds on the ''tau-neutrino mass'' do not apply if neutrino mixing is considered. The suppression of the population of the tau decay spectrum near the end point, caused by mixing, may be compensated by an enhancement because of a resonant mechanism of hadronization. It is necessary therefore to analyze the whole spectrum to infer some limit to the '' tau-neutrino mass.'' We argue that, consequently, neutrino mixing evades the objection to interpret the KARMEN anomaly as a heavy sequential neutrino.

Anomalous couplings of the third generation in rare B decays

We study the potential effects of anomalous couplings of the third generation quarks to gauge bosons in rare B decays. We focus on the constraints from flavor changing neutral current processes such as b→sγ and b →sl+l-. We consider both dimension-four and dimension-five operators and show that the latter can give large deviations from the standard model in the still unobserved dilepton modes, even after the bounds from b→sγ and precision electroweak observables are taken into account. ©2000 The American Physical Society.

Epsilon(b) constrainsts on self-couplings of vector bosons

We analyze the constraints on possible anomalous contributions to the W+W-Z vertex coming from non-universal radiative corrections to the Z → bb̄ width. We parametrize these corrections in terms of ∈b and use the LEP data to establish the allowed values for the anomalous triple couplings. We examine all CP conserving effective operators that exhibit SU(2)L × U(1)Y gauge invariance and do not give any tree level contribution to the present experimental observables. For some of these operators our constraints are comparable with the bounds coming from a global fit of the oblique parameters, which evidences the increasing relevance of the precise measurement of the b-quark parameters at LEP for the search of new physics.

Search for a nonstandard Higgs boson in diphoton events at p(p)over-bar collisions

We estimate the attainable limits on the coupling of a nonstandard Higgs boson to two photons taking into account the data collected by the Fermilab collaborations on diphoton events. We based our analysis on a general set of dimension-6 effective operators that give rise to anomalous couplings in the bosonic sector of the standard model. If the coefficients of all blind operators have the same magnitude, indirect bounds on the anomalous triple vector-boson couplings can also be inferred, provided there is no large cancellatton in the Higgs-gamma-gamma coupling.

Linking natural supersymmetry to flavour physics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ditregra - An auxiliary program for structural determination of diterpenes

This work describes the creation of heuristics rules based on 13C-NMR spectroscopy that characterize several skeletal types of diterpenes. Using a collection of 2745 spectra we built a database linked to the expert system SISTEMAT. Several programs were applied to the database in order to discover characteristic signals that identify with a good performance, a large diversity of skeletal types. The heuristic approach used was able to differentiate groups of skeletons based firstly on the number of primary, secondary, tertiary and quaternary carbons, and secondly the program searches, for each group, if there are ranges of chemical shifts that identifies specific skeletal type. The program was checked with 100 new structures recently published and was able to identify the correct skeleton in 65 of the studied cases. When the skeleton has several hundreds of compounds, for example, the labdanes, the program employs the concept of subskeletal, and does not classify in the same group labdanes with double bounds at different positions. The chemical shift ranges for each subskeletal types and the structures of all skeletal types are given. The consultation program can be obtained from the authors. © 1997 - IOS Press. All rights reserved.

Limits on a strong electroweak sector from e(+)e(-)->gamma gamma+E at LEP2

We study the process e+e- γγνν̄ in the context of a strong electroweak symmetry breaking model, which can be a source of events with two photons and missing energy at LEP2. We investigate bounds on the model assuming that no deviation is observed from the standard model within a given experimental error.

Formação inicial e concepções de assistentes sociais do interior do Rio Grande do Norte sobre a sexualidade da pessoa idosa

Pós-graduação em Educação Sexual - FCLAR

Limites dinâmicos para operadores de Schrödinger com potenciais Sturmianos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hybrid methods for lot sizing on parallel machines

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Uma nova forma de narrar a história: a renovação do romance histórico em Luiz Ruffato

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Um estudo sobre limites duais para o problema integrado de dimensionamento de lotes e sequenciamento da produção

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)