The Landau Distribution for Charged Particles Traversing Thin Films

The Landau distribution as well as its first and second momenta are well suited for describing the energy loss of charged particles traversing a thin layer of matter. At present, just rational approximations and asymptotic expressions for these functions were obtained. In this paper we present a direct calculation of the integral representation of these functions obtaining perturbative and nonperturvative solutions expressed in terms of fast convergent series. We also provide a simple numerical algorithm which allows to control speed and precision of the results. The testing runs have provided, in reasonable computing times, correct results up to 13-14 significant digits on the density and distribution functions and 9-10 on the first and second momenta. If necessary, this accuracy could be improved by adding more coefficients to the algorithm.Comment: 29 pages, 4 Table

General solution of laplace and poisson equations in a multiply connected circular domain : Applications to torsion

The general solution of Laplace and Poisson equations in multiply connected domains, in terms of the group of automorphism, is summarized. The particular application to the analysis of rods under torsion is presented. Different generalizations are discussed.Instituto de Física La Plat

Venus Atmosphere Profile from a Maximum Entropy Principle

The variational method with constraints recently developed by Verkley and Gerkema to describe maximum-entropy atmospheric profiles is generalized to ideal gases but with temperature-dependent specific heats. In so doing, an extended and non standard potential temperature is introduced that is well suited for tackling the problem under consideration. This new formalism is successfully applied to the atmosphere of Venus. Three well defined regions emerge in this atmosphere up to a height of $100 km$ from the surface: the lowest one up to about $35 km$ is adiabatic, a transition layer located at the height of the cloud deck and finally a third region which is practically isothermal.Comment: 6 pages, 3 figure

Signatures of excited monopolium

We study electromagnetic properties of particles with magnetic moment and no charge using their behavior when traversing coils and solenoids. These particles via the Faraday-Lenz law create a current whose energy we calculate. We analyze both the case of very long lived, almost stable, particles and those with a finite lifetime. We use this development to study the behavior of monopolium a monopole-antimonopole bound state in its excited states.Fil: Fanchiotti, Huner. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: García Canal, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Traini, Marco. Universita degli Studi di Trento; ItaliaFil: Vento, Vicente. Universidad de Valencia; Españ

Monte Carlo calculations on the gauge Potts model

The q-state gauge Potts model Pq in d-dimensions has been studied using Monte Carlo techniques. For d=2 no phase transitions were detected. The P2 model for d=3 shows a second order phase transition. On the other hand, all the d=3 (q≠2) and d=4 cases studied show first order phase transitions. In these cases, it was possible to estimate transition coupling parameters as well as latent heat. For selected cases, a study of the behavior of the Wilson loop factor was done.Facultad de Ciencias Exacta

Analytic structure of the S-matrix for singular quantum mechanics

The analytic structure of the S-matrix of singular quantum mechanics is examined within a multichannel framework, with primary focus on its dependence with respect to a parameter (Ω) that determines the boundary conditions. Specifically, a characterization is given in terms of salient mathematical and physical properties governing its behavior. These properties involve unitarity and associated current-conserving Wronskian relations, time-reversal invariance, and Blaschke factorization. The approach leads to an interpretation of effective nonunitary solutions in singular quantum mechanics and their determination from the unitary family.Instituto de Física La PlataConsejo Nacional de Investigaciones Científicas y Técnica

Convergence of the lowest-order photon-photon scattering amplitude in the gauge theories

In 1967 WEINBERG proposed an unif ied theory of electromagnetic and weak interactions of leptons and suggested that the theory might be renormalizable. Recent developments give strong support to this conjecture (~). More recently WEINBERG emphasized that his original model is one of a large class of gauge theories in which the gauge symmetry is spontaneously broken. The Higgs-Kibble (4) mechanism allows then the elimination of the associated Goldstone bosons and gives rise to the masses of the bosons and leptons. Lately a number of theories of this class have been proposed. In this note we discuss the convergence properties of the lowes t-order diagrams contributing to the physical photon-photon scattering amplitude in the gauge theories.Facultad de Ciencias Exacta

The Landau Distribution for Charged Particles Traversing Thin Films

The Landau distribution as well as its first and second momenta are well suited for describing the energy loss of charged particles traversing a thin layer of matter. At present, just rational approximations and asymptotic expressions for these functions were obtained. In this paper we present a direct calculation of the integral representation of these functions obtaining perturbative and nonperturvative solutions expressed in terms of fast convergent series. We also provide a simple numerical algorithm which allows to control speed and precision of the results. The testing runs have provided, in reasonable computing times, correct results up to 13-14 significant digits on the density and distribution functions and 9-10 on the first and second momenta. If necessary, this accuracy could be improved by adding more coefficients to the algorithm.Facultad de Ciencias Exacta