DOCSLIB.ORG

Electromagnetic Properties of Light and Heavy Baryons in the Relativistic Quark Model

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Electromagnetic Properties of Light and Heavy Baryons in the Relativistic Quark Model Electromagnetic Properties of Light and Heavy Baryons in the Relativistic Quark Model Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften der Fakult¨atf¨urMathematik und Physik der Eberhard-Karls-Universit¨atzu T¨ubingen vorgelegt von Diana Nicmorus Marinescu aus Ploiesti (Rum¨anien) 2007 Tag der m¨undlichen Pr¨ufung:14. Juni 2007 Dekan: Prof. Dr. Nils Schopohl 1. Berichterstatter: Prof. Dr. Thomas Gutsche 2. Berichterstatter: Prof. Dr. Dr. h.c. mult. Amand F¨aßler Suena de capao, corazon cabao .... Abstract One of the main challenges of nowadays low-energy physics remains the description of the internal structure of hadrons, strongly connected to the electromagnetic properties of matter. In this vein, the success of the relativistic quark model in the analysis of the hadron structure constitutes a solid motivation for the study carried out throughout this work. The relativistic quark model is extended to the inves- tigation of static electromagnetic properties of both heavy and light baryons. The bare contributions to the magnetic moments of the single-, double- and triple-heavy baryons are calculated. Moreover, the relativistic quark model allows the study of the electromagnetic properties of the light baryon octet incorporating meson cloud contributions in a perturbative manner. The long disputed values of the multipole ratios E2/M1 and C2/M1 and the electro- magnetic form factors of the N ∆γ transition are successfully reproduced. The relativistic quark model→ can be viewed as a quantum field theory approach based on a phenomenological Lagrangian coupling light and heavy baryons to their constituent quarks. In our approach the baryon is a compos- ite object of three constituent quarks, at least in leading order. The effective interaction Lagrangian is written in terms of baryon and constituent quark fields. The effective action preserves Lorentz covariance and gauge invari- ance. The main ingredients of the model are already introduced at the level of the interaction Lagrangian: the three-quark baryon currents, the Gaussian distribution of the constituent quarks inside the baryon and the composite- ness condition which sets an upper limit for the baryon-quark vertex. The S-matrix elements are expressed by a set of Feynman quark-diagrams. The model contains only few parameters, namely, the cut-off parameter of the Gaussian quark distribution and the free quark propagator, which are un- ambiguously determined from the best fit to the data. The heavy quark limit within this model reveals an exact agreement in leading order with the model-independent predictions for the magnetic moments of the heavy baryons. For the light sector, a Lorentz covariant chiral quark Lagrangian is used to dress the constituent quarks by pseudoscalar meson clouds. The main achievement consists in the factorization of the valence quark contribu- tions and the meson cloud contributions in the calculation of electromagnetic properties of light baryons. Abstrakt Eine der Hauptherausforderungen der heutigen Niederenergiephysik besteht in der Beschreibung der internen Struktur von Hadronen, welche im en- gen Zusammenhang mit den elektromagnetischen Eigenschaften der Ma- terie zusammenh¨angt.Der vorherige Erfolg des relativistischen Quarkmod- ells in der Analyse der Hadronenstruktur stellt eine solide Grundlage f¨ur die Untersuchungen, welche in dieser Arbeit durchgef¨uhrtwerden, dar. In diesem Zugang wird das Baryon, zumindest in f¨uhrenderOrdnung, durch den Bindungszustand aus Konstituentenquarks beschrieben. Das relativistische Quarkmodell wird in der vorliegenden Arbeit erweitert, um die statischen, elektromagnetischen Eigenschaften von schweren und le- ichten Baryonen zu untersuchen. Das relativistische Quarkmodell basiert auf einen quantenfeldtheoretischen Zugang, welcher, in einer ph¨anomenologischen Lagrange-Dichte formuliert, die Kopplung von leichten und schweren Bary- onen an die Konstituentenquarks beschreibt. Die entsprechende effektive Wirkung erh¨altLorentz-Kovarianz und Eichinvarianz. Die Hauptannahmen des Modells werden auf dem Niveau der Wechselwirkungs Lagrange-Dichte eingef¨uhrt:Drei-Quark Baryonen-Str¨ome,die Gauss-Verteilung der Konsti- tutentenquarks im Baryon und die sogenannte ’compositeness condition’, welche die Kopplung der nackten Baryonen an die Konstituentenquarks bes- timmt. Die entsprechenden S-Matrix Elemente werden durch einen Satz von Feynman-Quark-Diagrammen ausgedr¨uckt. Das relativistische Quarkmodell beinhaltet einen Satz von wenigen Parametern: Breite der Gaussverteilung und Konstituentenquarkmassen, welche durch Anpassung an vorherige Daten fixiert werden. Die Valenzquarkbeitr¨agezu den magnetischen Mometen der einfach, dop- pelt und dreifach schweren Baryonen werden berechnet. Im Limes schw- erer Quarkmassen kann innerhalb dieses Modells in f¨uhrenderOrdnung ex- akte Ubereinstimmung¨ mit den modell-unabh¨angigenVorhersagen zu den magnetischen Momenten schwerer Baryonen erreicht werden. Im leichten Baryonen-Sektor wird zus¨atzlich ein Lorentz kovariante, chirale Quark-La- grange-Dichte genutzt, um die See-Quark Beitr¨age,ausgedr¨uckt durch pseu- doskalare Mesonen, in Konsistenz mit chiraler Symmetrie einzubinden. Die chirale Lagrange-Dichte wird zur Ordnung O(p4) und in der Einschleifen- N¨aherungausgewertet, um die durch die chiralen Effekte angezogenen Quark- operatoren zu bestimmen. Das Hauptergebnis dieser Technik ist, dass die Beitr¨ageder Mesonen und der Valenzquarks in den elektromagnetischen, baryonischen Amplituden faktorisieren. Anwendungen dieser chiralen Er- weiterung des relativistischen Quarkmodell auf elektromagnetischen Eigen- schaften des leichten Baryonen-Oktetts werden ausgearbeitet. Zus¨atzlich studieren wir die elektromagnetischen N ∆ Uberg¨ange,wo¨ relativistische Effekte eine entscheidende Rolle spielen.− Insbesondere k¨onnendie Multi- polverh¨altnisse E2/M1, C2/M1 und die elektromagnetischen Formfaktoren des radiativen Ubergangs¨ N ∆γ erfolgreich reproduziert werden. → Contents 1 Introduction 9 1.1 Models of the baryons . 10 1.2 Chiral Perturbation Theory . 14 1.3 Heavy Quark Effective Theory . 23 2 Relativistic Three Quark Model 29 2.1 General overview . 29 2.2 Three-quark baryon currents . 33 2.3 Compositeness condition . 45 2.4 Electromagnetic interaction . 47 3 Magnetic moments of heavy baryons 51 3.1 Baryon mass operator and matrix elements . 58 3.2 Heavy-quark limit and matching to Heavy Hadron ChPT . 63 3.3 Numerical results and discussion . 66 4 Magnetic moments of light baryons 75 4.1 Matrix elements of valence quark operators . 83 4.2 Matching to ChPT . 84 4.3 Light baryon magnetic moments . 86 5 N ∆γ transition 101 − 6 Summary 121 A Representations of the Lorentz group 127 7 8 CONTENTS B Three-quark currents 131 B.1 Light baryons . 131 B.2 Heavy baryons . 132 B.3 Baryon wave functions . 134 C Feynman rules for the non-local electromagnetic vertex 137 D Calculation of matrix elements 141 E Non-relativistic spin-flavor wave functions and magnetic mo- ments 145 F Relativistic form factors for the N ∆γ transition 147 → G Uniqueness of the ∆+(1232) three-quark current 149 Chapter 1 Introduction In this work we investigate the structure of baryons applying a relativistic constituent quark model. Properties of both light and heavy baryons are studied in a quantum field theory approach [1, 2]. Baryons are systems governed by the strong interaction. We aim to de- scribe such interactions introducing a phenomenological Lorentz covariant and gauge invariant Lagrangian. Due to the success of the naive quark model predictions for static baryon properties [3, 4, 5, 6] and motivated by the re- sults of deep inelastic lepton scattering, it is reasonable to think of baryons in leading order as composite systems of three quarks. The prototype of a such system is the nucleon. The model we describe here has been already developed and applied to the nucleon, and later on improved for a series of low energy processes obeyed by other heavier states [7, 8, 9, 10, 11, 12]. Among various attempts to describe the low-energy behaviour of nucleons in a relativistic framework, our approach has particular advantages: it is rather intuitive, employs a solid and within quantum field theory consistent calculational technique, has a fixed and small number of parameters. Our results are in good agreement with other models and effective approaches. Moreover, our approach recovers model independent predictions, as the ones offered by chiral perturbation theory and heavy quark effective theory. Having in mind the importance and success of these approaches we will start by giving a short overview on the naive quark models, on the basics of chiral perturbation theory and heavy quark symmetry. We continue with an overview of the main issues of the relativistic quark model, followed by two applications: the calculation of magnetic moments of single-, double-, triple- heavy baryons and the calculation of magnetic moments of light baryons, 9 10 CHAPTER 1. INTRODUCTION taking into consideration meson cloud effects. A challenging aspect is the study of the N ∆ transition, which we will present in the last part of this work. → The nucleon and its observed detailed properties are of great impor- tance to understand and test the theory of strong interaction. A theoretical study of the nucleon collects phenomena associated with QCD (confinement, spontaneous symmetry breaking, and asymptotic freedom) as well as phe- nomenological approaches, that is models. At low energies it is possible to obtain model independent predictions
Load more

Recommended publications
  • Quasiparticle Anisotropic Hydrodynamics in Ultra-Relativistic
    QUASIPARTICLE ANISOTROPIC HYDRODYNAMICS IN ULTRA-RELATIVISTIC HEAVY-ION COLLISIONS A dissertation submitted to Kent State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy by Mubarak Alqahtani December, 2017 c Copyright All rights reserved Except for previously published materials Dissertation written by Mubarak Alqahtani BE, University of Dammam, SA, 2006 MA, Kent State University, 2014 PhD, Kent State University, 2014-2017 Approved by , Chair, Doctoral Dissertation Committee Dr. Michael Strickland , Members, Doctoral Dissertation Committee Dr. Declan Keane Dr. Spyridon Margetis Dr. Robert Twieg Dr. John West Accepted by , Chair, Department of Physics Dr. James T. Gleeson , Dean, College of Arts and Sciences Dr. James L. Blank Table of Contents List of Figures . vii List of Tables . xv List of Publications . xvi Acknowledgments . xvii 1 Introduction ......................................1 1.1 Units and notation . .1 1.2 The standard model . .3 1.3 Quantum Electrodynamics (QED) . .5 1.4 Quantum chromodynamics (QCD) . .6 1.5 The coupling constant in QED and QCD . .7 1.6 Phase diagram of QCD . .9 1.6.1 Quark gluon plasma (QGP) . 12 1.6.2 The heavy-ion collision program . 12 1.6.3 Heavy-ion collisions stages . 13 1.7 Some definitions . 16 1.7.1 Rapidity . 16 1.7.2 Pseudorapidity . 16 1.7.3 Collisions centrality . 17 1.7.4 The Glauber model . 19 1.8 Collective flow . 21 iii 1.8.1 Radial flow . 22 1.8.2 Anisotropic flow . 22 1.9 Fluid dynamics . 26 1.10 Non-relativistic fluid dynamics . 26 1.10.1 Relativistic fluid dynamics .
    [Show full text]
  • Wave-Whirl-Particle Gudrun Kalmbach H.E University of Ulm, MINT Verlag, Germany
    OSP Journal of Nuclear Science Short Communication Wave-Whirl-Particle Gudrun Kalmbach H.E University of Ulm, MINT Verlag, Germany Corresponding Author: Gudrun Kalmbach H.E, University of Ulm, MINT Verlag, Germany Received: December 19, 2019; Accepted: December 26, 2019; Published: January 02, 2019 In earlier articles the author suggested to extend the wave For dark energy and matter are suggested a pinched and a particle duality of physics to a triple, adding whirls. Whirls Horn torus with a singularity. Below are two models for this: are mathematically computed differently than waves. Parti- dark energy has inverted frequency helix lines inside and cles can be considered as a kind of bubble formation in other aggregate phase state. Wave equations have a double Minkowski cone. They have higher speeds than light 1-dimensional space expansion in direction where a wave is their cylindrical location is closed at projective infinity by a travelling. Harmonic waves for a vibrating string miss this are inverted at the Schwarzschild radius to 1-dimensional coordinate. Sound expands through pressure on the other lemniscates,inside the pinched drawn torus.with twoIn figure red or 1 greenis shown or bluethat quarkswings. hand in a sound cone. Measured is its power as intensity per All quarks are joined in this kind of pinched torus at their free carrying one of the three olor charges r, g, b,in nucle- area (figure 1). center as the Horn torus singularity. (figure 2) They are set - onsons, arebut whirls,confined often in nucleons drawn as by stretchable the two color springs charged between gluon twoquasiparticles quarks as (fieldend points; quantums) different as an geometries energy exchange.
    [Show full text]
  • Coupled Wire Model of Z4 Orbifold Quantum Hall States
    Coupled Wire Model of Z4 Orbifold Quantum Hall States Charles L. Kane Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 Ady Stern Department of Condensed Matter Physics, The Weizmann Institute of Science, Rehovot 76100, Israel We introduce a coupled wire model for a sequence of non-Abelian quantum Hall states that generalize the Z4 parafermion Read Rezayi state. The Z4 orbifold quantum Hall states occur at filling factors ν = 2=(2m − p) for odd integers m and p, and have a topological order with a neutral sector characterized by the orbifold conformal field theory with central charge c = 1 at radius p R = p=2. When p = 1 the state is Abelian. The state with p = 3 is the Z4 Read Rezayi state, and the series of p ≥ 3 defines a sequence of non-Abelian states that resembles the Laughlin sequence. Our model is based on clustering of electrons in groups of four, and is formulated as a two fluid model in which each wire exhibits two phases: a weak clustered phase, where charge e electrons coexist with charge 4e bosons and a strong clustered phase where the electrons are strongly bound in groups of 4. The transition between these two phases on a wire is mapped to the critical point of the 4 state clock model, which in turn is described by the orbifold conformal field theory. For an array of wires coupled in the presence of a perpendicular magnetic field, strongly clustered wires form a charge 4e bosonic Laughlin state with a chiral charge mode at the edge, but no neutral mode and a gap for single electrons.
    [Show full text]
  • Thermodynamics of Hot Hadronic Gases at Finite Baryon Densities
    Thermodynamics of Hot Hadronic Gases at Finite Baryon Densities A THESIS SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL OF THE UNIVERSITY OF MINNESOTA BY Michael Glenn Albright IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy Joseph Kapusta, Advisor November, 2015 c Michael Glenn Albright 2015 ALL RIGHTS RESERVED Acknowledgements First, I would like to express my sincerest appreciation to my advisor, Joseph Kapusta, for all of his guidance and assistance throughout my time as a graduate student at the University of Minnesota. I would also like to thank Clint Young, my research collaborator, for his helpful suggestions. I would also like to thank my parents, Chris and Glenn, and my sister Jaime. Your love and support throughout the years made this possible. Finally, I thank the members of my thesis committee: Marco Peloso, Roberta Humphreys, and Roger Rusack. This work was supported by the School of Physics and Astronomy at the University of Minnesota, by a University of Minnesota Graduate School Fellowship, and by the US Department of Energy (DOE) under Grant Number DE-FG02-87ER40328. I also acknowledge computational support from the University of Minnesota Supercomputing Institute. Programming their supercomputers was a fun and memorable experience. i Dedication To my parents, Chris and Glenn, and my sister Jaime|thanks. ii Abstract In this thesis we investigate equilibrium and nonequilibrium thermodynamic prop- erties of Quantum Chromodynamics (QCD) matter at finite baryon densities. We begin by constructing crossover models for the thermodynamic equation of state. These use switching functions to smoothly interpolate between a hadronic gas model at low energy densities to a perturbative QCD equation of state at high energy densities.
    [Show full text]
  • Quark Structure of Pseudoscalar Mesons Light Pseudoscalar Mesons Can Be Identified As (Almost) Goldstone Bosons
    International Journal of Modern Physics A, c❢ World Scientific Publishing Company QUARK STRUCTURE OF PSEUDOSCALAR MESONS THORSTEN FELDMANN∗ Fachbereich Physik, Universit¨at Wuppertal, Gaußstraße 20 D-42097 Wuppertal, Germany I review to which extent the properties of pseudoscalar mesons can be understood in terms of the underlying quark (and eventually gluon) structure. Special emphasis is put on the progress in our understanding of η-η′ mixing. Process-independent mixing parameters are defined, and relations between different bases and conventions are studied. Both, the low-energy description in the framework of chiral perturbation theory and the high-energy application in terms of light-cone wave functions for partonic Fock states, are considered. A thorough discussion of theoretical and phenomenological consequences of the mixing approach will be given. Finally, I will discuss mixing with other states 0 (π , ηc, ...). 1. Introduction The fundamental degrees of freedom in strong interactions of hadronic matter are quarks and gluons, and their behavior is controlled by Quantum Chromodynamics (QCD). However, due to the confinement mechanism in QCD, in experiments the only observables are hadrons which appear as complex bound systems of quarks and gluons. A rigorous analytical solution of how to relate quarks and gluons in QCD to the hadronic world is still missing. We have therefore developed effective descriptions that allow us to derive non-trivial statements about hadronic processes from QCD and vice versa. It should be obvious that the notion of quark or gluon structure may depend on the physical context. Therefore one aim is to find process- independent concepts which allow a comparison of different approaches.
    [Show full text]
  • Arxiv:1702.08417V3 [Hep-Ph] 31 Aug 2017
    Strong couplings and form factors of charmed mesons in holographic QCD Alfonso Ballon-Bayona,∗ Gast~aoKrein,y and Carlisson Millerz Instituto de F´ısica Te´orica, Universidade Estadual Paulista, Rua Dr. Bento Teobaldo Ferraz, 271 - Bloco II, 01140-070 S~aoPaulo, SP, Brazil We extend the two-flavor hard-wall holographic model of Erlich, Katz, Son and Stephanov [Phys. Rev. Lett. 95, 261602 (2005)] to four flavors to incorporate strange and charm quarks. The model incorporates chiral and flavor symmetry breaking and provides a reasonable description of masses and weak decay constants of a variety of scalar, pseudoscalar, vector and axial-vector strange and charmed mesons. In particular, we examine flavor symmetry breaking in the strong couplings of the ρ meson to the charmed D and D∗ mesons. We also compute electromagnetic form factors of the π, ρ, K, K∗, D and D∗ mesons. We compare our results for the D and D∗ mesons with lattice QCD data and other nonperturbative approaches. I. INTRODUCTION are taken from SU(4) flavor and heavy-quark symmetry relations. For instance, SU(4) symmetry relates the cou- There is considerable current theoretical and exper- plings of the ρ to the pseudoscalar mesons π, K and D, imental interest in the study of the interactions of namely gρDD = gKKρ = gρππ=2. If in addition to SU(4) charmed hadrons with light hadrons and atomic nu- flavor symmetry, heavy-quark spin symmetry is invoked, clei [1{3]. There is special interest in the properties one has gρDD = gρD∗D = gρD∗D∗ = gπD∗D to leading or- of D mesons in nuclear matter [4], mainly in connec- der in the charm quark mass [27, 28].
    [Show full text]
  • Analysis of Pseudoscalar and Scalar $D$ Mesons and Charmonium
    PHYSICAL REVIEW C 101, 015202 (2020) Analysis of pseudoscalar and scalar D mesons and charmonium decay width in hot magnetized asymmetric nuclear matter Rajesh Kumar* and Arvind Kumar† Department of Physics, Dr. B. R. Ambedkar National Institute of Technology Jalandhar, Jalandhar 144011 Punjab, India (Received 27 August 2019; revised manuscript received 19 November 2019; published 8 January 2020) In this paper, we calculate the mass shift and decay constant of isospin-averaged pseudoscalar (D+, D0 ) +, 0 and scalar (D0 D0 ) mesons by the magnetic-field-induced quark and gluon condensates at finite density and temperature of asymmetric nuclear matter. We have calculated the in-medium chiral condensates from the chiral SU(3) mean-field model and subsequently used these condensates in QCD sum rules to calculate the effective mass and decay constant of D mesons. Consideration of external magnetic-field effects in hot and dense nuclear matter lead to appreciable modification in the masses and decay constants of D mesons. Furthermore, we also ψ ,ψ ,χ ,χ studied the effective decay width of higher charmonium states [ (3686) (3770) c0(3414) c2(3556)] as a 3 by-product by using the P0 model, which can have an important impact on the yield of J/ψ mesons. The results of the present work will be helpful to understand the experimental observables of heavy-ion colliders which aim to produce matter at finite density and moderate temperature. DOI: 10.1103/PhysRevC.101.015202 I. INTRODUCTION debateable topic. Many theories suggest that the magnetic field produced in HICs does not die immediately due to the Future heavy-ion colliders (HIC), such as the Japan Proton interaction of itself with the medium.
    [Show full text]
  • Quark Diagram Analysis of Bottom Meson Decays Emitting Pseudoscalar and Vector Mesons
    Quark Diagram Analysis of Bottom Meson Decays Emitting Pseudoscalar and Vector Mesons Maninder Kaur†, Supreet Pal Singh and R. C. Verma Department of Physics, Punjabi University, Patiala – 147002, India. e-mail: [email protected], [email protected] and [email protected] Abstract This paper presents the two body weak nonleptonic decays of B mesons emitting pseudoscalar (P) and vector (V) mesons within the framework of the diagrammatic approach at flavor SU(3) symmetry level. Using the decay amplitudes, we are able to relate the branching fractions of B PV decays induced by both b c and b u transitions, which are found to be well consistent with the measured data. We also make predictions for some decays, which can be tested in future experiments. PACS No.:13.25.Hw, 11.30.Hv, 14.40.Nd †Corresponding author: [email protected] 1. Introduction At present, several groups at Fermi lab, Cornell, CERN, DESY, KEK and Beijing Electron Collider etc. are working to ensure wide knowledge of the heavy flavor physics. In future, a large quantity of new and accurate data on decays of the heavy flavor hadrons is expected which calls for their theoretical analysis. Being heavy, bottom hadrons have several channels for their decays, categorized as leptonic, semi-leptonic and hadronic decays [1-2]. The b quark is especially interesting in this respect as it has W-mediated transitions to both first generation (u) and second generation (c) quarks. Standard model provides satisfactory explanation of the leptonic and semileptonic decays but weak hadronic decays confronts serious problem as these decays experience strong interactions interferences [3-6].
    [Show full text]
  • Non-Perturbative Gluons and Pseudoscalar Mesons in Baryon Spectroscopy
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE Non-perturbative Gluons and Pseudoscalar Mesons in Baryonprovided by CERN Document Server Spectroscopy Z. Dziembowskia, M. Fabre de la Ripelleb, and Gerald A. Millerc a Department of Physics Temple University Philadelphia, PA 19122 b Institut de Physique Nucleaire, Universite de Paris-Sud, 94106 Orsay, France c Department of Physics University of Washington, Box 351560 Seattle, WA 98195-1560 Abstract We study baryon spectroscopy including the effects of pseudoscalar meson exchange and one gluon exchange potentials between quarks, governed by αs. The non-perturbative, hyperspherical method calculations show that one can obtain a good description of the data by using a quark-meson coupling con- stant that is compatible with the measured pion-nucleon coupling constant, and a reasonably small value of αs. Typeset using REVTEX 1 Interest in studying baryon spectroscopy has been re-vitalized by the recent work of Glozman and Riska [1–5]. These authors point out the persistent difficulty in obtaining a simultaneous description of the masses of the P-wave baryon resonances and the Roper- nucleon mass difference. In particular they argue [2] that “the spectra of the nucleons, ∆ resonances and the strange hyperons are well described by the constituent quark model, if in addition to the harmonic confinement potential the quarks are assumed to interact by exchange of the SU(3)F octet of pseudoscalar mesons”. Furthermore, Ref. [5] states that gluon exchange has no relation with the spectrum of baryons ! The ideas of Glozman and Riska are especially interesting because of the good descrip- tions of the spectra obtained in Refs.
    [Show full text]
  • Qcd Matter Under Extreme Conditions Heavy Ion
    Technische Universitat¨ Munchen¨ Physik Department Institut fur¨ Theoretische Physik T39 Univ.-Prof. Dr. W. Weise QCD MATTER UNDER EXTREME CONDITIONS — HEAVY ION COLLISIONS Dipl.-Phys. (Univ.) Thorsten Renk Vollstandiger¨ Abdruck der von der Fakultat¨ fur¨ Physik der Technischen Universitat¨ Munchen¨ zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. Reiner Kruc¨ ken Pruf¨ er der Dissertation: 1. Univ.-Prof. Dr. Wolfram Weise 2. Univ.-Prof. Dr. Manfred Lindner Die Dissertation wurde am 22.10.2002 bei der Technischen Universitat¨ Munchen¨ eingereicht und durch die Fakultat¨ fur¨ Physik am 3.12.2002 angenommen. ii CONTENTS 1 Introduction 1 2 Basics of thermal field theory 5 2.1 Basic relations . 5 2.2 Perturbative techniques . 6 2.2.1 The imaginary time formalism . 7 2.2.2 The real-time formalism . 8 2.3 Thermal self-energies . 10 2.4 Hard Thermal Loop Resummation . 11 2.5 Lattice techniques . 12 2.5.1 Gauge fields . 13 2.5.2 Fermion fields . 13 3 Properties of the Quark Gluon Plasma 15 3.1 Thermodynamics of the QGP . 16 3.1.1 The ideal quark-gluon gas . 16 3.1.2 Perturbative QCD thermodynamics . 17 3.1.3 Lattice simulations . 19 3.2 Deconfinement . 21 3.3 Chiral symmetry restoration . 22 3.4 A quasiparticle picture of the QGP . 24 3.4.1 Introduction . 24 3.4.2 The quasiparticle picture . 24 3.5 The Equation of State . 26 4 Heavy Ion Collision Dynamics 29 4.1 Introduction . 29 4.2 Kinematics and Geometry . 30 4.2.1 Kinematic variables .
    [Show full text]
  • Decay Constants of Pseudoscalar and Vector Mesons with Improved Holographic Wavefunction Arxiv:1805.00718V2 [Hep-Ph] 14 May 20
    Decay constants of pseudoscalar and vector mesons with improved holographic wavefunction Qin Chang (8¦)1;2, Xiao-Nan Li (NS`)1, Xin-Qiang Li (N新:)2, and Fang Su (Ϲ)2 ∗ 1Institute of Particle and Nuclear Physics, Henan Normal University, Henan 453007, China 2Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University, Wuhan, Hubei 430079, China Abstract We calculate the decay constants of light and heavy-light pseudoscalar and vector mesons with improved soft-wall holographic wavefuntions, which take into account the effects of both quark masses and dynamical spins. We find that the predicted decay constants, especially for the ratio fV =fP , based on light-front holographic QCD, can be significantly improved, once the dynamical spin effects are taken into account by introducing the helicity-dependent wavefunctions. We also perform detailed χ2 analyses for the holographic parameters (i.e. the mass-scale parameter κ and the quark masses), by confronting our predictions with the data for the charged-meson decay constants and the meson spectra. The fitted values for these parameters are generally in agreement with those obtained by fitting to the Regge trajectories. At the same time, most of our results for the decay constants and their ratios agree with the data as well as the predictions based on lattice QCD and QCD sum rule approaches, with arXiv:1805.00718v2 [hep-ph] 14 May 2018 only a few exceptions observed. Key words: light-front holographic QCD; holographic wavefuntions; decay constant; dynamical spin effect ∗Corresponding author: [email protected] 1 1 Introduction Inspired by the correspondence between string theory in anti-de Sitter (AdS) space and conformal field theory (CFT) in physical space-time [1{3], a class of AdS/QCD approaches with two alter- native AdS/QCD backgrounds has been successfully developed for describing the phenomenology of hadronic properties [4,5].
    [Show full text]
  • ELEMENTARY PARTICLES in PHYSICS 1 Elementary Particles in Physics S
    ELEMENTARY PARTICLES IN PHYSICS 1 Elementary Particles in Physics S. Gasiorowicz and P. Langacker Elementary-particle physics deals with the fundamental constituents of mat- ter and their interactions. In the past several decades an enormous amount of experimental information has been accumulated, and many patterns and sys- tematic features have been observed. Highly successful mathematical theories of the electromagnetic, weak, and strong interactions have been devised and tested. These theories, which are collectively known as the standard model, are almost certainly the correct description of Nature, to first approximation, down to a distance scale 1/1000th the size of the atomic nucleus. There are also spec- ulative but encouraging developments in the attempt to unify these interactions into a simple underlying framework, and even to incorporate quantum gravity in a parameter-free “theory of everything.” In this article we shall attempt to highlight the ways in which information has been organized, and to sketch the outlines of the standard model and its possible extensions. Classification of Particles The particles that have been identified in high-energy experiments fall into dis- tinct classes. There are the leptons (see Electron, Leptons, Neutrino, Muonium), 1 all of which have spin 2 . They may be charged or neutral. The charged lep- tons have electromagnetic as well as weak interactions; the neutral ones only interact weakly. There are three well-defined lepton pairs, the electron (e−) and − the electron neutrino (νe), the muon (µ ) and the muon neutrino (νµ), and the (much heavier) charged lepton, the tau (τ), and its tau neutrino (ντ ). These particles all have antiparticles, in accordance with the predictions of relativistic quantum mechanics (see CPT Theorem).
    [Show full text]