Stability of Three- and Four-Body Coulomb Systems

We discuss the stability of three- and four-particle system interacting by pure Coulomb interactions, as a function of the masses and charges of the particles. We present a certain number of general properties which allow to answer a certain number of questions without or with less numerical calculations.Comment: latex file, 15 pages, 8 figure

The status of the heavy quark systems

We review various inequalities on the order and the spacing of energy levels, wave function at the origin, etc... which were obtained since 1977 in the framework of the Schrodinger equation and applied to quarkonium and also to muonic atoms and alcaline atoms. We also present a fit of mesons and baryons made of b, c, s quarks and antiquarks, keeping the 1981 parameters and comparing with present experimental data.Comment: 21 pages, 3 figure

Free group automorphisms with many fixed points at infinity

A concrete family of automorphisms alpha_n of the free group F_n is exhibited, for any n > 2, and the following properties are proved: alpha_n is irreducible with irreducible powers, has trivial fixed subgroup, and has 2n-1 attractive as well as 2n repelling fixed points at bdry F_n. As a consequence of a recent result of V Guirardel there can not be more fixed points on bdry F_n, so that this family provides the answer to a question posed by G Levitt.Comment: This is the version published by Geometry & Topology Monographs on 29 April 200

Investigation of the Role of Elastic Unitarity in High-Energy Scattering: Gribov's Theorem and the Froissart Bound

We re-examine V. Gribov's theorem of 1960 according to which the total cross-section cannot approach a finite non-zero limit with, at the same time, a diffraction peak having a finite slope. We are very close to proving by an explicit counter-example that elastic unitarity in the elastic region is an essential ingredient of the proof. By analogy, we raise the question of the saturation of the Froissart-Martin bound, for which no examples incorporating elastic unitarity exist at the present time.Comment: 11 pages, 1 figures, latex with sproc.st

Scattering problems in elastodynamics

In electromagnetism, acoustics, and quantum mechanics, scattering problems can routinely be solved numerically by virtue of perfectly matched layers (PMLs) at simulation domain boundaries. Unfortunately, the same has not been possible for general elastodynamic wave problems in continuum mechanics. In this paper, we introduce a corresponding scattered-field formulation for the Navier equation. We derive PMLs based on complex-valued coordinate transformations leading to Cosserat elasticity-tensor distributions not obeying the minor symmetries. These layers are shown to work in two dimensions, for all polarizations, and all directions. By adaptative choice of the decay length, the deep subwavelength PMLs can be used all the way to the quasi-static regime. As demanding examples, we study the effectiveness of cylindrical elastodynamic cloaks of the Cosserat type and approximations thereof

LUX likelihood and limits on spin-independent and spin-dependent WIMP couplings with LUXCalc

We present LUXCalc, a new utility for calculating likelihoods and deriving WIMP-nucleon coupling limits from the recent results of the LUX direct search dark matter experiment. After a brief review of WIMP-nucleon scattering, we derive LUX limits on the spin-dependent WIMP-nucleon couplings over a broad range of WIMP masses, under standard assumptions on the relevant astrophysical parameters. We find that, under these and other common assumptions, LUX excludes the entire spin-dependent parameter space consistent with a dark matter interpretation of DAMA's anomalous signal, the first time a single experiment has been able to do so. We also revisit the case of spin-independent couplings, and demonstrate good agreement between our results and the published LUX results. Finally, we derive constraints on the parameters of an effective dark matter theory in which a spin-1 mediator interacts with a fermionic WIMP and Standard Model fermions via axial-vector couplings. A detailed appendix describes the use of LUXCalc with standard codes to place constraints on generic dark matter theories.Comment: 16 pages, 6 figures. Software package included as ancillary files. v2: added references, Baksan limits. v3: clarifications and small corrections, results unchange

Masculinity: Understanding Authority Across Institutional Settings as Social Control

Masculinity is observed here as it relates to authority, and as it functions within discourse surrounding the American penal and health care institutions. Understandings of race and gender are dictated by beliefs that masculinity can be “achieved,” or functions as a value within society. This piece works to stress that masculinity is instead a worldview, which assists in the distinguishing and perpetuation of dichotomy tied to plays of superiority and inferiority. It is for this reason, when recognizing masculinity within a capitalist global context, abolition becomes a necessary approach, when attempting to confront masculinized authority and institutions