A stochastic theory of particle transport

1977 ◽  
Vol 358 (1692) ◽  
pp. 105-120 ◽  
Keyword(s):  
Particle Physics ◽  
Neutron Transport ◽  
Stochastic Theory ◽  
Single Chain ◽  
Amorphous Medium ◽  
History Of ◽  
Backward Equation ◽  
Mean And Variance ◽  
The Green Function ◽  
Regeneration Point

A probability balance equation is formulated for the number of particles present in a cascade resulting from multiple births at each collision. Janossy’s regeneration point method is used and it leads to an integro differential equation for the generating function from which statistical information can readily be extracted. The technique is applied to the interpretation of radiation damage cascades in a homogeneous, amorphous medium in which two particles are ‘born’ per collision. The history of a single chain is followed and equations for the mean and variance are obtained as well as for individual probabilities. It is further shown how the backward and forward forms of the Boltzmann equation are related via the Green function of the system. Additional study shows that the variance also obeys a forward type of equation although its solution is not obtained as conveniently as that of the corresponding backward equation. Several analogies are made with other branches of particle physics; in particular, cosmic rays and neutron transport.

scholarly journals Dynamical Symmetries of the H Atom, One of the Most Important Tools of Modern Physics: SO(4) to SO(4,2), Background, Theory, and Use in Calculating Radiative Shifts

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1323 ◽  
Author(s):  
G. Jordan Maclay
Keyword(s):  
Hydrogen Atom ◽  
Quantum Electrodynamics ◽  
Particle Physics ◽  
Bound States ◽  
Integrated Treatment ◽  
Invariance Group ◽  
Elementary Particle Physics ◽  
Background Theory ◽  
Modern Physics ◽  
History Of

Understanding the hydrogen atom has been at the heart of modern physics. Exploring the symmetry of the most fundamental two body system has led to advances in atomic physics, quantum mechanics, quantum electrodynamics, and elementary particle physics. In this pedagogic review, we present an integrated treatment of the symmetries of the Schrodinger hydrogen atom, including the classical atom, the SO(4) degeneracy group, the non-invariance group or spectrum generating group SO(4,1), and the expanded group SO(4,2). After giving a brief history of these discoveries, most of which took place from 1935–1975, we focus on the physics of the hydrogen atom, providing a background discussion of the symmetries, providing explicit expressions for all of the manifestly Hermitian generators in terms of position and momenta operators in a Cartesian space, explaining the action of the generators on the basis states, and giving a unified treatment of the bound and continuum states in terms of eigenfunctions that have the same quantum numbers as the ordinary bound states. We present some new results from SO(4,2) group theory that are useful in a practical application, the computation of the first order Lamb shift in the hydrogen atom. By using SO(4,2) methods, we are able to obtain a generating function for the radiative shift for all levels. Students, non-experts, and the new generation of scientists may find the clearer, integrated presentation of the symmetries of the hydrogen atom helpful and illuminating. Experts will find new perspectives, even some surprises.

scholarly journals Quasi-Steady State Cosmology

1994 ◽  
Vol 159 ◽  
pp. 293-299
Author(s):  
G. Burbidge ◽  
F. Hoyle ◽  
J.V. Narlikar
Keyword(s):  
Steady State ◽  
Early Universe ◽  
Particle Physics ◽  
Physical Theory ◽  
Big Bang ◽  
Quasi Steady State ◽  
Recent Developments ◽  
History Of ◽  
The Big Bang ◽  
The Universe

The standard big bang cosmology has the universe created out of a primeval explosion that not only created matter and radiation but also spacetime itself. The big bang event itself cannot be discussed within the framework of a physical theory but the events following it are in principle considered within the scope of science. The recent developments on the frontier between particle physics and cosmology highlight the attempts to chart the history of the very early universe.

Constructing Quarks: A Sociological History of Particle Physics

1986 ◽  
Vol 54 (4) ◽  
pp. 381-383 ◽  
Author(s):  
Andrew Pickering ◽  
James T. Cushing
Keyword(s):  
Particle Physics ◽  
History Of Particle Physics ◽  
History Of ◽  
Sociological History

scholarly journals Muon to electron conversion: how to find an electron in a muon haystack

2010 ◽  
Vol 368 (1924) ◽  
pp. 3645-3655 ◽  
Author(s):  
A. Kurup
Keyword(s):  
Particle Physics ◽  
Energy Production ◽  
Electron Transition ◽  
Neutrino Factory ◽  
The Past ◽  
The Standard Model ◽  
Electron Conversion ◽  
History Of ◽  
Physics Experiments ◽  
The Universe

The standard model (SM) of particle physics describes how the Universe works at a fundamental level. Even though this theory has proven to be very successful over the past 50 years, we know it is incomplete. Many theories that go beyond the SM predict the occurrence of certain processes that are forbidden by the SM, such as muon to electron conversion. This paper will briefly review the history of muon to electron conversion and focus on the high-precision experiments currently being proposed, COMET (Coherent Muon to Electron Transition) and Mu2e, and a next-generation experiment, PRISM. The PRISM experiment intends to use a novel type of accelerator called a fixed-field alternating-gradient (FFAG) accelerator. There has recently been renewed interest in FFAGs for the Neutrino Factory and the Muon Collider, and because they have applications in many areas outside of particle physics, such as energy production and cancer therapy. The synergies between these particle physics experiments and other applications will also be discussed.

scholarly journals Composição histórica da teoria eletrofraca: da reformulação V-A à detecção dos bósons W+, W- e Z0

2021 ◽  
Vol 7 (1) ◽  
pp. 57
Author(s):  
Marcia da Costa ◽  
Irinéa de Lourdes Batista
Keyword(s):  
Particle Physics ◽  
Primary Sources ◽  
Theory Theory ◽  
Electroweak Theory ◽  
Scientific Content ◽  
Cognitive Values ◽  
Electromagnetic Interactions ◽  
New Directions ◽  
History Of ◽  
Structure Of Matter

Este trabalho tem o objetivo de apresentar uma Composição Histórica a respeito de estudos que culminaram na elaboração da teoria de unificação das interações eletromagnéticas e fracas, a Teoria Eletrofraca. Entende-se que as contribuições teóricas e experimentais envolvidas nesse processo constituíram novos rumos para a Física de Partículas daquela época e elucidaram questões relevantes para o entendimento da estrutura da matéria. Neste artigo, serão apresentados estudos que partem da Teoria V-A, apresentam as primeiras hipóteses de bósons mediadores para a interação fraca, possíveis relações entre as interações fracas e eletromagnéticas, e as contribuições teóricas e experimentais que consolidaram a Teoria Eletrofraca.  Este artigo foi elaborado com base em encaminhamentos metodológicos de pesquisas em História da Ciência e pressupostos da elaboração de uma Composição Histórica, considerando fontes primárias e seguindo os princípios de inteligibilidade, valores cognitivos e fidedignidade, que resultam em um material que reúne elementos históricos, epistemológicos, axiológicos e científicos para a inteligibilidade de um conteúdo científico com objetivos pedagógicos e de disseminação de conhecimentos.Historical composition of electroweak theory: from V-A reformulation to detection of W+, W- and Z0 bosonsAbstractThis paper aims to present a Historical Composition about studies that culminated in the elaboration of the theory of unification of weak and electromagnetic interactions, the Electroweak Theory. It is understood that the theoretical and experimental contributions involved in this process constitute new directions for Particle Physics of that time and clarified relevant issues for the understanding of the structure of matter. In this article we will present studies that depart from Theory V-A, present the first hypothesis of mediating bosons for the weak interaction, possible relations between weak and electromagnetic interactions, and the theoretical and experimental contributions that consolidated the Electro-Theory Theory. This article was elaborated based on methodological referrals of research in History of Science and assumptions of the elaboration of a Historical Composition, considering primary sources and following the principles of intelligibility, cognitive values and reliability, which result in a material that brings together historical, epistemological elements axiological and scientific for the intelligibility of a scientific content with pedagogical purpose and knowledge dissemination.Keywords: Electroweak theory; Historical composition; Unification; Historical experiments.

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