Download or read book Experimental Determination of the Effective Strong Coupling Constant written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We extract an effective strong coupling constant from low Q2 data on the Bjorken sum. Using sum rules, we establish its Q2-behavior over the complete Q2-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
Download or read book Experimental Determination of an Effective Coupling Constant written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum chromodynamics (QCD), the theory of the strong force, describes the interactions of two basic building blocks of matter: quarks and gluons. High precision data taken at the Jefferson Lab electron accelerator provide a solid basis for the detailed study of many aspects of QCD. The accelerator's beam energy permits investigations of the transition between the short distance and long distance regimes of the strong force. Understanding how the descriptions of these regimes are related is essential in comprehending the structure of ordinary matter. Using new data from polarized electron - nucleon scattering, we extract the scale dependence of an effective strong coupling constant, $\alpha_{\rm{s}}^{\rm{eff}}$. Our result shows that this effective charge freezes, i.e. loses its scale dependence, at long (nucleon-size) distances. This finite behavior allows us to obtain a physical coupling constant for the strong interaction that is relevant at all scales.
Download or read book Precision Determination of the Strong Coupling Constant written by Riccardo Abbate and published by . This book was released on 2012 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we study the event shapes variable thrust. Event shape variables are observables that characterize the shape of the distribution of the final state particles of a reaction. We take advantage of the formalism of Soft Collinear Effective Theory (SCET), an effective theory of the strong interactions appropriate for describing energetic jets. We give a factorization theorem for the process e+e- to hadrons, valid in the whole range of thrust values. This factorization theorem resums large logarithms at the N3LL accuracy and contains the full O(a) result for the fixed order cross section. In order to be able to describe the whole range of thrust values, we define the profile functions, which are thrust-dependent factorization scales which smoothly interpolate between regions where resummation of large logarithms is important and where it is not. To determine non perturbative effects, we fit renormalon-free nonperturbative matrix elements of operators defined in field theory, Q1. We perform a global analysis to all available thrust data in the tail region, where a two parameter fit to a,(mz) and the first power correction Q1 suffices. We find cr(mz) = 0.1135 i (0.0002)expt ± (0.0005)hadr ± (0.0009)pert, with X2 /dof(= 485) = 0.91, where the displayed 1-sigma errors are the total experimental error, the hadronization uncertainty, and the perturbative theory uncertainty, respectively. Furthermore, we perform a global analysis to all available data on the first moment of the thrust distribution. This analysis is a partially independent check of the tail fit, in fact it probes different regions of the thrust distribution and the analysis of experimental systematic uncertainties was conducted independently with respect to the data for the distribution. We find a,(mz) = 0.1141 i (0.0004)exp ± (0.0014)hadr ± (0.0007)pert with X2/dof(= 45) = 1.33. We also consider pp collisions, in particular the Drell-Yan process. Here we calculate analytically the beam thrust logarithms of the relevant beam functions and of the coefficient function at O(a2). This is a necessary ingredient for the calculation of the nonsingular terms in resummed predictions.
Download or read book On the Origin of Natural Constants written by Hans Peter Good and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-10-22 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Just as the circle number π or the Euler constant e determines mathematics, fundamental constants of nature define the scales of the natural sciences. This book presents a new perspective by means of a few axioms and compares the resulting validity with experimental data. By the axiomatic approach Sommerfeld's mysterious fine-structure constant and Dirac's cosmic number are fixed as pure number constants. Thanks to these number constants, it is possible to calculate the value for the anomalous magnetic-moment of the electron in a simple way compared to QED calculations. With the same number constants it is also possible to calculate masses, partial lifetimes, magnetic-moments or charge radii of fundamental particles. The expressions used for the calculations, with few exceptions, yield values within the experimental error limits of the Particle Data Group. The author shows that the introduced number constants give even better predictions than the complicated QED calculations of today's doctrine. In the first part only experimental data from the literature for checking the postulates are used. In the second part the author explains electrical transport measurements with emergent behaviour, which were carried out in a professional environment.
Download or read book Advances in Magnetic and Optical Resonance written by Warren S. Warren and published by Elsevier. This book was released on 1996-12-06 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1965, Advances in Magnetic and Optical Resonance has provided researchers with timely expositions of fundamental new developments in the theory of, experimentation with, and application of magnetic and optical resonance.
Download or read book Particle Symmetries written by Max Chrétien and published by CRC Press. This book was released on 1966 with total page 718 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Conference on Continuous Advances in QCD 2004 written by T. Gherghetta and published by World Scientific. This book was released on 2004 with total page 603 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains articles on the latest research in QCD from some of the leading experts in the field. These are based on talks presented at the Continuous Advances in QCD 2004 workshop held at the William I Fine Theoretical Physics Institute.The book will be a useful reference source for graduate students and researchers in high energy physics.The proceedings have been selected for coverage in: ? Index to Scientific & Technical Proceedings? (ISTP? / ISI Proceedings)? Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)? CC Proceedings ? Engineering & Physical Sciences
Download or read book Physics In Collision Proceedings Of The 15th International Conference written by Krzysztof Rybicki and published by World Scientific. This book was released on 1996-01-23 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive overview of high energy physics. It covers the whole range of results from the colliders and fixed-target experiments as well as the astrophysics topics related to particle physics. Also discussed are the problems of proton structure, electroweak physics, non-perturbative QCD and heavy quarks.
Download or read book Determination of the Strong Coupling Constant alpha sub S and a Test of Perturbative QCD Using W Jets Processes in the D0 Detector written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The D0 experiment has accumulated data for a study of inclusive W production corresponding to a total integrated luminosity of 14.3 [plus-minus] 1.7 pb[sup [minus]1] during the 1992--1993 Fermilab Tevatron collider run. The total number of W [yields] e + [nu] candidates is 9770. The ratio of the number of W + 1 jet events to that of W + 0 jet events has been measured as a function of jet minimum E[sub T]. Using this ratio the strong coupling constant, [alpha][sub s] at Q[sup 2] = M[sub W][sup 2] is measured to be [alpha][sub s](M[sub W][sup 2]) = 0.124 [plus-minus] 0.005(stat) [plus-minus] 0.006(MC) [plus-minus] 0.008(theory)[sub [minus]0.022][sup +0.026](sys) or ([sub [minus]0.025][sup +0.028] combined) with a jet minimum E[sub T] of 25 GeV. A quantitative test of perturbative QCD has been made by comparing the experimentally measured ratio with the theoretical predictions. The theoretical predictions of the ratio in both the leading order and next-to-leading order are in good agreement with the measured ratio.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975-03 with total page 988 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NMR Crystallography written by Robin K. Harris and published by John Wiley & Sons. This book was released on 2012-12-19 with total page 523 pages. Available in PDF, EPUB and Kindle. Book excerpt: The content of this volume has been added to eMagRes (formerly Encyclopedia of Magnetic Resonance) - the ultimate online resource for NMR and MRI. The term "NMR Crystallography" has only recently come into common usage, and even now causes raised eyebrows within some parts of the diffraction community. The power of solid-state NMR to give crystallographic information has considerably increased since the CPMAS suite of techniques was introduced in 1976. In the first years of the 21st century, the ability of NMR to provide information to support and facilitate the analysis of single-crystal and powder diffraction patterns has become widely accepted. Indeed, NMR can now be used to refine diffraction results and, in favorable cases, to solve crystal structures with minimal (or even no) diffraction data. The increasing ability to relate chemical shifts (including the tensor components) to the crystallographic location of relevant atoms in the unit cell via computational methods has added significantly to the practice of NMR crystallography. Diffraction experts will increasingly welcome NMR as an allied technique in their structural analyses. Indeed, it may be that in the future crystal structures will be determined by simultaneously fitting diffraction patterns and NMR spectra. This Handbook is organised into six sections. The first contains an overview and some articles on fundamental NMR topics, followed by a section concentrating on chemical shifts, and one on coupling interactions. The fourth section contains articles describing how NMR results relate to fundamental crystallography concepts and to diffraction methods. The fifth section concerns specific aspects of structure, such as hydrogen bonding. Finally, four articles in the sixth section give applications of NMR crystallography to structural biology, organic & pharmaceutical chemistry, inorganic & materials chemistry, and geochemistry. About EMR Handbooks / eMagRes Handbooks The Encyclopedia of Magnetic Resonance (up to 2012) and eMagRes (from 2013 onward) publish a wide range of online articles on all aspects of magnetic resonance in physics, chemistry, biology and medicine. The existence of this large number of articles, written by experts in various fields, is enabling the publication of a series of EMR Handbooks / eMagRes Handbooks on specific areas of NMR and MRI. The chapters of each of these handbooks will comprise a carefully chosen selection of articles from eMagRes. In consultation with the eMagRes Editorial Board, the EMR Handbooks / eMagRes Handbooks are coherently planned in advance by specially-selected Editors, and new articles are written (together with updates of some already existing articles) to give appropriate complete coverage. The handbooks are intended to be of value and interest to research students, postdoctoral fellows and other researchers learning about the scientific area in question and undertaking relevant experiments, whether in academia or industry. Have the content of this Handbook and the complete content of eMagRes at your fingertips! Visit: www.wileyonlinelibrary.com/ref/eMagRes View other eMagRes publications here
Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1985 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Advanced Course in Computational Nuclear Physics written by Morten Hjorth-Jensen and published by Springer. This book was released on 2017-05-09 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: This graduate-level text collects and synthesizes a series of ten lectures on the nuclear quantum many-body problem. Starting from our current understanding of the underlying forces, it presents recent advances within the field of lattice quantum chromodynamics before going on to discuss effective field theories, central many-body methods like Monte Carlo methods, coupled cluster theories, the similarity renormalization group approach, Green’s function methods and large-scale diagonalization approaches. Algorithmic and computational advances show particular promise for breakthroughs in predictive power, including proper error estimates, a better understanding of the underlying effective degrees of freedom and of the respective forces at play. Enabled by recent improvements in theoretical, experimental and numerical techniques, the state-of-the art applications considered in this volume span the entire range, from our smallest components – quarks and gluons as the mediators of the strong force – to the computation of the equation of state for neutron star matter. The lectures presented provide an in-depth exposition of the underlying theoretical and algorithmic approaches as well details of the numerical implementation of the methods discussed. Several also include links to numerical software and benchmark calculations, which readers can use to develop their own programs for tackling challenging nuclear many-body problems.
Download or read book Origin Of Mass And Strong Coupling Gauge Theories Scgt 15 Proceedings Of The Sakata Memorial Kmi Workshop written by Yasumichi Aoki and published by World Scientific. This book was released on 2017-12-06 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains contributions to the workshop, which was largely focused on the strong coupling gauge theories in search for theories beyond the standard model, particularly, the LHC experiments and lattice studies of conformal fixed point. The main topics include walking technicolor and the role of conformality in view of the 125 GeV Higgs as a light composite Higgs (technidilaton, and other composite Higgs, etc.). Nonperturbative studies like lattice simulations and stringy/holographic approaches are extensively discussed in close relation to the phenomenological studies.After the discovery of 125 GeV Higgs at LHC, the central issue of particle physics is now to reveal the dynamical origin of the Higgs itself. One of the possibilities would be the composite Higgs based on the strong coupling gauge theory in the TeV region, such as the technidilaton predicted in walking technicolor with infrared conformality. The volume contains, among others, many of the latest important reports on walking technicolor and related subjects in the general context of conformality, in a way of direct relevance to the LHC phenomenology as well as the lattice studies. It is very timely to study full theoretical implications in the exciting era when the LHC is vigorously working. This volume is of great importance for that purpose.Speakers of 40 talks (plus posters) include K-I Aoki, Y Aoki, K Bamba, E Bennett, R S Chivukula, H Georgi, A Hasenfratz, D-K Hong, K Itoh, D Elander, G Fleming, H Fukano, Y Iwasaki, M Jarvinen, D Kadoh, S Kim, R Kitano, K-I Kondo, J Kuti, D Lin, N Maru, H Matsufuru, S Matsuzaki, K-I Nagai, C Nonaka, H Ohki, E Pallante, M Rho, E Rinaldi, F Sannino, D Schaich, A Shibata, R E Shrock, E H Simmons, K Tuominen, C H Wong, N Yamada, M J S Yang, and K Yamawaki.
Download or read book High Energy Physics 99 Proceedings of the International Europhysics Conference on High Energy Physics Tampere Finland 15 21 July 1999 written by K Huitu and published by CRC Press. This book was released on 2000-01-01 with total page 1112 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Energy Physics 99 contains the 18 invited plenary presentations and 250 contributions to parallel sessions presented at the International Europhysics Conference on High Energy Physics. The book provides a comprehensive survey of the latest developments in high energy physics. Topics discussed include hard high energy, structure functions, soft interactions, heavy flavor, the standard model, hadron spectroscopy, neutrino masses, particle astrophysics, field theory, and detector development.
Download or read book Strangeness Nuclear Physics Proceedings Of The Apctp Workshop Snp 99 written by Il-t Cheon and published by World Scientific. This book was released on 2000-09-27 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique role of strangeness in nuclear physics has recently attracted much attention, from both the theoretical and experimental viewpoints. This is due not only to the broad spectrum of possible hadron many-body systems with strangeness, but also to the fact that strangeness gives us an opportunity to study fundamental baryon-baryon interactions in a new perspective. Our knowledge of this subject has widened as the scope of hypernuclear experiments has expanded from strangeness exchange and the associated production reactions to hypernuclear weak decays, β decays, cascade hypernuclei, double-Λ events, electroproduction of strangeness, etc. This trend will be accelerated by the full operation of new laboratories such as TJLab, COSY, DAΦNE, JHF, MAMI, and others. Various aspects of those important and exciting topics are discussed in this book in order to get a perspective of this fast developing area of nuclear physics.
Download or read book Physics And Experiments With Linear Colliders Lcws95 Proceedings Of The Workshop In 2 Volumes written by Yoshiaki Fujii and published by World Scientific. This book was released on 1996-08-22 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collider experiments have become essential to studying elementary particles. In particular, lepton collisions such as e⁺e⁻ are ideal from both experimental and theoretical points of view, and are a unique means of probing the new energy region, sub-TeV to TeV. It is a common understanding that a next-generation e⁺e⁻ collider will have to be a linear machine that evades beam-energy losses due to synchrotron radiation. In this book, physics feasibilities at linear colliders are discussed in detail, taking into account the recent progress in high-energy physics.
