The Dirac oscillator in a spinning cosmic string spacetime

We examine the effects of gravitational fields produced by topological defects on a Dirac field and a Dirac oscillator in a spinning cosmic string spacetime. We obtain the eigenfunctions and the energy levels of the relativistic field in that background and consider the effect of various parameters, such as the frequency of the rotating frame, the oscillator's frequency, the string density and other quantum numbers.Comment: 12 pages, 3 figure

Quasi-Elastic Neutrino Reactions on Carbon and Lead Nuclei

We examine neutral-current quasi-elastic neutrino-nucleus reactions on $^{12}$C and $^{208}$Pb targets. We use the relativistic mean field theory approach to describe the nuclear dynamics. We compute the cross sections for the scattering of 150-MeV, 500-MeV and 1000-MeV neutrinos on a $^{12}$C target and study the effect of the strange-quark content of the nucleon which appears in these reactions via the isoscalar weak current. We compare our results with the data of the MiniBooNE experiment for mineral oil (CH$_2$). We also calculate the cross section for the quasi-elastic neutron knockout reaction of 20 to 60-MeV neutrinos on a $^{208}$Pb target which is relevant to plans to use lead as a target material in future supernova neutrino detectors.Comment: 28 pages, 14 figure

Lorentz violation in a family of (1+2)(1+2)-dimensional wormhole

We study neutral Dirac particles confined to a family of $(1+2)$-dimensional wormholes arising from surfaces of revolution with a constant negative Gaussian curvature, in the framework of a comprehensive effective field theory allowing deviations from Lorentz symmetry: the gravitational standard-model extension (SME). The Dirac particles are described with a fixed background tensor field that rules the Lorentz symmetry violation in the CPT-even gauge sector of SME. We implement this geometrical approach by incorporating non-minimal couplings that possibly induce a Lorentz-symmetry violating term in the modified Dirac equation. We also analyze the exact analytical solutions of the corresponding modified Dirac equation in the presence of a peculiar external magnetic field

On Deformations and Contractions of Lie Algebras

In this contributed presentation, we discuss and compare the mutually opposite procedures of deformations and contractions of Lie algebras. We suggest that with appropriate combinations of both procedures one may construct new Lie algebras. We first discuss low-dimensional Lie algebras and illustrate thereby that whereas for every contraction there exists a reverse deformation, the converse is not true in general. Also we note that some Lie algebras belonging to parameterized families are singled out by the irreversibility of deformations and contractions. After reminding that global deformations of the Witt, Virasoro, and affine Kac-Moody algebras allow one to retrieve Lie algebras of Krichever-Novikov type, we contract the latter to find new infinite dimensional Lie algebras

Graded Contractions of Affine Kac-Moody Algebras

The method of graded contractions, based on the preservation of the automorphisms of finite order, is applied to the affine Kac-Moody algebras and their representations, to yield a new class of infinite dimensional Lie algebras and representations. After the introduction of the horizontal and vertical gradings, and the algorithm to find the horizontal toroidal gradings, I discuss some general properties of the graded contractions, and compare them with the In\"on\"u-Wigner contractions. The example of $\hat A_2$ is discussed in detail.Comment: 23 pages, Ams-Te

Evaluation of intersectoral collaborations : "Relevailles" and intersectoral collaborations. Brief Report.

HIGHLIGHTS • In 3 of the 4 cases, the key actor in the collaborative network was the OCF coordinator/liaison officer. • All the networks were vulnerable to the departure of a key actor. • Collaborative networks did not include any perinatal assistants. • 35 of the 37 HSSE actors involved in collaborative networks belonged to a local community services centre (CLSC), even when there was a birthing hospital or birthing centre in the HSSE. • Five determinants contributed to or constrained intersectoral collaborations between OCFs and HSSEs. • Sufficiency of resources, knowledge of the partner organization, and complementarity/flexibility in the delivery of services were determinants of collaborations. • Six modes of OCF/HSSE collaboration were identified. • There are few formal mechanisms for collaboration between organizations. • Disagreements/misunderstandings on the mechanisms for sharing information about families occurred between organizations and even within organizations. • Some parents perceived links between OCFs and CLSCs as falling into two modes of collaboration, namely 1) activating the request/recourse to partner organization services and 2) coordinating the services provided to families