Hasil untuk "Physics"

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S2 Open Access 1984
Gauge Theory of elementary particle physics

T. Cheng, Ling-Fong. Li, D. Gross

This is a practical introduction to the principal ideas in gauge theory and their applications to elementary particle physics. It explains technique and methodology with simple exposition backed up by many illustrative examples. Derivations, some of well known results, are presented in sufficient detail to make the text accessible to readers entering the field for the first time. The book focuses on the strong interaction theory of quantum chromodynamics and the electroweak interaction theory of Glashow, Weinberg, and Salam, as well as the grand unification theory, exemplified by the simplest SU(5) model. Not intended as an exhaustive survey, the book nevertheless provides the general background necessary for a serious student who wishes to specialize in the field of elementary particle theory. Physicists with an interest in general aspects of gauge theory will also find the book highly useful.

1200 sitasi en Physics
S2 Open Access 2008
Recent Progress and New Challenges in Isospin Physics with Heavy-Ion Reactions

Bao-An Li, Lie-Wen Chen, C. Ko

The ultimate goal of studying isospin physics via heavy-ion reactions with neutron-rich, stable and/or radioactive nuclei is to explore the isospin dependence of in-medium nuclear effective interactions and the equation of state of neutron-rich nuclear matter, particularly the isospin-dependent term in the equation of state, i.e., the density dependence of the symmetry energy. Because of its great importance for understanding many phenomena in both nuclear physics and astrophysics, the study of the density dependence of the nuclear symmetry energy has been the main focus of the intermediate-energy heavy-ion physics community during the last decade, and significant progress has been achieved both experimentally and theoretically. In particular, a number of phenomena or observables have been identified as sensitive probes to the density dependence of the nuclear symmetry energy. Experimental studies have confirmed some of these interesting isospin-dependent effects and allowed us to constrain relatively stringently the symmetry energy at sub-saturation densities. The impacts of this constrained density dependence of the symmetry energy on the properties of neutron stars have also been studied, and they were found to be very useful for the astrophysical community. With new opportunities provided by the various radioactive beam facilities being constructed around the world, the study of isospin physics is expected to remain one of the forefront research areas in nuclear physics. In this report, we review the major progress achieved during the last decade in isospin physics with heavy ion reactions and discuss future challenges to the most important issues in this field.

933 sitasi en Physics
S2 Open Access 2004
The Physics of Neutron Stars

J. Lattimer, M. Prakash

Neutron stars are some of the densest manifestations of massive objects in the universe. They are ideal astrophysical laboratories for testing theories of dense matter physics and provide connections among nuclear physics, particle physics, and astrophysics. Neutron stars may exhibit conditions and phenomena not observed elsewhere, such as hyperon-dominated matter, deconfined quark matter, superfluidity and superconductivity with critical temperatures near 1010 kelvin, opaqueness to neutrinos, and magnetic fields in excess of 1013 Gauss. Here, we describe the formation, structure, internal composition, and evolution of neutron stars. Observations that include studies of pulsars in binary systems, thermal emission from isolated neutron stars, glitches from pulsars, and quasi-periodic oscillations from accreting neutron stars provide information about neutron star masses, radii, temperatures, ages, and internal compositions.

963 sitasi en Physics, Medicine
S2 Open Access 1999
Astroparticle Physics

N. Magnussen

This article reviews some recent developments in Astroparticle Physics. Due to the extension of the field only part of the results and developments can be covered. The status of the search for Dark Matter, some recent results on Cosmic Rays and Gamma Ray Astronomy and the status of Neutrino Astronomy are presented.

950 sitasi en Physics
S2 Open Access 2013
Handbook of Accelerator Physics and Engineering

A. Chao, K. Mess, M. Tigner et al.

Concerned with the design and operation of modern accelerators including linacs, synchrotrons and storage rings, this text includes both theoretical and practical matters. Chapters on beam dynamics and electromagnetic and nuclear interactions deals with linear and nonlinear single particle and collective effects including spin motion, beam-environment, beam-beam and intrabeam interactions. The impedance concept and calculations are covered along with the instabilities associated with the various interactions mentioned. A chapter on operational considerations deals with orbit error assessment and correction. Chapters on mechanical and electrical considerations present material data and aspects of component design including heat transfer and refrigeration. Hardware systems for particle sources, feedback systems, confinement and acceleration (both normal conduction and superconducting) receive detailed treatment in a subsystems chapter, which also covers beam measurement techniques and apparatus. The closing chapter gives data and methods for radiation protection computations as well as much data on radiation damage to various materials and devices.

645 sitasi en Physics
S2 Open Access 2013
Parton physics on a Euclidean lattice.

X. Ji

I show that the parton physics related to correlations of quarks and gluons on the light cone can be studied through the matrix elements of frame-dependent, equal-time correlators in the large momentum limit. This observation allows practical calculations of parton properties on a Euclidean lattice. As an example, I demonstrate how to recover the leading-twist quark distribution by boosting an equal-time correlator to a large momentum.

489 sitasi en Physics, Medicine
S2 Open Access 2014
Amplitude/Higgs Modes in Condensed Matter Physics

D. Pekker, C. Varma

The order parameter and its variations in space and time in many different states in condensed matter physics at low temperatures are described by the complex function Ψ(r, t). These states include superfluids, superconductors, and a subclass of antiferromagnets and charge density waves. The collective fluctuations in the ordered state may then be categorized as oscillations of phase and amplitude of Ψ(r, t). The phase oscillations are the Goldstone modes of the broken continuous symmetry. The amplitude modes, even at long wavelengths, are well defined and are decoupled from the phase oscillations only near particle-hole symmetry, where the equations of motion have an effective Lorentz symmetry, as in particle physics and if there are no significant avenues for decay into other excitations. They bear close correspondence with the so-called Higgs modes in particle physics, whose prediction and discovery are very important for the standard model of particle physics. In this review, we discuss the theory and...

380 sitasi en Physics
DOAJ Open Access 2025
ODE, regression, and ANN models for energy forecasting: Egypt as a study case

Mohey Eldeen H. H. Ali, Ahmed F. Tayel, Hossam M. Ezzat et al.

Energy plays a crucial role in national development, influencing critical sectors such as industry, agriculture, healthcare, and education. Accurate energy consumption prediction is essential for efficient energy management, helping prevent imbalances between supply and demand and potential energy shortages. This study aims to forecast the total primary energy supply (TPES), using Egypt as a case study for the first time in literature and utilizing several models (ordinary differential equations (ODEs), regression, and ANN models). Although ordinary differential equations (ODEs) offer flexibility and convenience, their application in energy forecasting remains limited. One of the main objectives of this research is to evaluate the effectiveness of ODEs in predicting energy consumption. Various ODE and regression models are employed to identify the most suitable model amongst each category for forecasting energy demand. Additionally, an artificial neural network (ANN) is developed, trained, validated, and tested for the same forecasting task. The study compares the performance of the selected ODE model (Mendelsohn), with the selected regression model (Polynomial), and an ANN model predicting Egypt’s TPES until 2035. By assessing multiple forecasting methods, this work improves the accuracy and reliability of energy consumption predictions, which is crucial for sustainable energy planning and policy development.

Engineering (General). Civil engineering (General)

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