Electron-Positron Annihilation and the New Particles
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THE STRONG INTERACTION by J
MISN-0-280 THE STRONG INTERACTION by J. R. Christman 1. Abstract . 1 2. Readings . 1 THE STRONG INTERACTION 3. Description a. General E®ects, Range, Lifetimes, Conserved Quantities . 1 b. Hadron Exchange: Exchanged Mass & Interaction Time . 1 s 0 c. Charge Exchange . 2 d L u 4. Hadron States a. Virtual Particles: Necessity, Examples . 3 - s u - S d e b. Open- and Closed-Channel States . 3 d n c. Comparison of Virtual and Real Decays . 4 d e 5. Resonance Particles L0 a. Particles as Resonances . .4 b. Overview of Resonance Particles . .5 - c. Resonance-Particle Symbols . 6 - _ e S p p- _ 6. Particle Names n T Y n e a. Baryon Names; , . 6 b. Meson Names; G-Parity, T , Y . 6 c. Evolution of Names . .7 d. The Berkeley Particle Data Group Hadron Tables . 7 7. Hadron Structure a. All Hadrons: Possible Exchange Particles . 8 b. The Excited State Hypothesis . 8 c. Quarks as Hadron Constituents . 8 Acknowledgments. .8 Project PHYSNET·Physics Bldg.·Michigan State University·East Lansing, MI 1 2 ID Sheet: MISN-0-280 THIS IS A DEVELOPMENTAL-STAGE PUBLICATION Title: The Strong Interaction OF PROJECT PHYSNET Author: J. R. Christman, Dept. of Physical Science, U. S. Coast Guard The goal of our project is to assist a network of educators and scientists in Academy, New London, CT transferring physics from one person to another. We support manuscript Version: 11/8/2001 Evaluation: Stage B1 processing and distribution, along with communication and information systems. We also work with employers to identify basic scienti¯c skills Length: 2 hr; 12 pages as well as physics topics that are needed in science and technology. -
1.1. Introduction the Phenomenon of Positron Annihilation Spectroscopy
PRINCIPLES OF POSITRON ANNIHILATION Chapter-1 __________________________________________________________________________________________ 1.1. Introduction The phenomenon of positron annihilation spectroscopy (PAS) has been utilized as nuclear method to probe a variety of material properties as well as to research problems in solid state physics. The field of solid state investigation with positrons started in the early fifties, when it was recognized that information could be obtained about the properties of solids by studying the annihilation of a positron and an electron as given by Dumond et al. [1] and Bendetti and Roichings [2]. In particular, the discovery of the interaction of positrons with defects in crystal solids by Mckenize et al. [3] has given a strong impetus to a further elaboration of the PAS. Currently, PAS is amongst the best nuclear methods, and its most recent developments are documented in the proceedings of the latest positron annihilation conferences [4-8]. PAS is successfully applied for the investigation of electron characteristics and defect structures present in materials, magnetic structures of solids, plastic deformation at low and high temperature, and phase transformations in alloys, semiconductors, polymers, porous material, etc. Its applications extend from advanced problems of solid state physics and materials science to industrial use. It is also widely used in chemistry, biology, and medicine (e.g. locating tumors). As the process of measurement does not mostly influence the properties of the investigated sample, PAS is a non-destructive testing approach that allows the subsequent study of a sample by other methods. As experimental equipment for many applications, PAS is commercially produced and is relatively cheap, thus, increasingly more research laboratories are using PAS for basic research, diagnostics of machine parts working in hard conditions, and for characterization of high-tech materials. -
Electron - Positron Annihilation
Electron - Positron Annihilation γ µ K Z − − − + + + − − − + + + − − − − + + + − − − + + + + W ν h π D. Schroeder, 29 October 2002 OUTLINE • Electron-positron storage rings • Detectors • Reaction examples e+e− −→ e+e− [Inventory of known particles] e+e− −→ µ+µ− e+e− −→ q q¯ e+e− −→ W +W − • The future:Linear colliders Electron-Positron Colliders Hamburg Novosibirsk 11 GeV 12 GeV 47 GeV Geneva 200 GeV Ithaca Tokyo Stanford 12 GeV 64 GeV 8 GeV 12 GeV 30 GeV 100 GeV Beijing 12 GeV 4 GeV Size (R) and Cost ($) of an e+e− Storage Ring βE4 $=αR + ( E = beam energy) R d $ βE4 Find minimum $: 0= = α − dR R2 β =⇒ R = E2, $=2 αβ E2 α SPEAR: E = 8 GeV, R = 40 m, $ = 5 million LEP: E = 200 GeV, R = 4.3 km, $ = 1 billion + − + − Example 1: e e −→ e e e− total momentum = 0 θ − total energy = 2E e e+ Probability(E,θ)=? e+ E-dependence follows from dimensional analysis: density = ρ− A density = ρ+ − + × 2 Probability = (ρ− ρ+ − + A) (something with units of length ) ¯h ¯hc When E m , the only relevant length is = e p E 1 =⇒ Probability ∝ E2 at SPEAR Augustin, et al., PRL 34, 233 (1975) 6000 5000 4000 Ecm = 4.8 GeV 3000 2000 Number of Counts 1000 Theory 0 −0.8 −0.40 0.40.8 cos θ Prediction for e+e− −→ e+e− event rate (H. J. Bhabha, 1935): event dσ e4 1 + cos4 θ 2 cos4 θ 1 + cos2 θ ∝ = 2 − 2 + rate dΩ 32π2E2 4 θ 2 θ 2 cm sin 2 sin 2 Interpretation of Bhabha’sformula (R. -
QCD at Colliders
Particle Physics Dr Victoria Martin, Spring Semester 2012 Lecture 10: QCD at Colliders !Renormalisation in QCD !Asymptotic Freedom and Confinement in QCD !Lepton and Hadron Colliders !R = (e+e!!hadrons)/(e+e!"µ+µ!) !Measuring Jets !Fragmentation 1 From Last Lecture: QCD Summary • QCD: Quantum Chromodymanics is the quantum description of the strong force. • Gluons are the propagators of the QCD and carry colour and anti-colour, described by 8 Gell-Mann matrices, !. • For M calculate the appropriate colour factor from the ! matrices. 2 2 • The coupling constant #S is large at small q (confinement) and large at high q (asymptotic freedom). • Mesons and baryons are held together by QCD. • In high energy collisions, jets are the signatures of quark and gluon production. 2 Gluon self-Interactions and Confinement , Gluon self-interactions are believed to give e+ q rise to colour confinement , Qualitative picture: •Compare QED with QCD •In QCD “gluon self-interactions squeeze lines of force into Gluona flux tube self-Interactions” ande- Confinementq , + , What happens whenGluon try self-interactions to separate two are believedcoloured to giveobjects e.g. qqe q rise to colour confinement , Qualitativeq picture: q •Compare QED with QCD •In QCD “gluon self-interactions squeeze lines of force into a flux tube” e- q •Form a flux tube, What of happensinteracting when gluons try to separate of approximately two coloured constant objects e.g. qq energy density q q •Require infinite energy to separate coloured objects to infinity •Form a flux tube of interacting gluons of approximately constant •Coloured quarks and gluons are always confined within colourless states energy density •In this way QCD provides a plausible explanation of confinement – but not yet proven (although there has been recent progress with Lattice QCD) Prof. -
Charm Meson Molecules and the X(3872)
Charm Meson Molecules and the X(3872) DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Masaoki Kusunoki, B.S. ***** The Ohio State University 2005 Dissertation Committee: Approved by Professor Eric Braaten, Adviser Professor Richard J. Furnstahl Adviser Professor Junko Shigemitsu Graduate Program in Professor Brian L. Winer Physics Abstract The recently discovered resonance X(3872) is interpreted as a loosely-bound S- wave charm meson molecule whose constituents are a superposition of the charm mesons D0D¯ ¤0 and D¤0D¯ 0. The unnaturally small binding energy of the molecule implies that it has some universal properties that depend only on its binding energy and its width. The existence of such a small energy scale motivates the separation of scales that leads to factorization formulas for production rates and decay rates of the X(3872). Factorization formulas are applied to predict that the line shape of the X(3872) differs significantly from that of a Breit-Wigner resonance and that there should be a peak in the invariant mass distribution for B ! D0D¯ ¤0K near the D0D¯ ¤0 threshold. An analysis of data by the Babar collaboration on B ! D(¤)D¯ (¤)K is used to predict that the decay B0 ! XK0 should be suppressed compared to B+ ! XK+. The differential decay rates of the X(3872) into J=Ã and light hadrons are also calculated up to multiplicative constants. If the X(3872) is indeed an S-wave charm meson molecule, it will provide a beautiful example of the predictive power of universality. -
On the Possibility of Experimental Detection of Virtual Particles in Physical Vacuum Anatolii Pavlenko* Open International University of Human Development, Ukraine
onm Pavlenko, J Environ Hazard 2018, 1:1 nvir en f E ta o l l H a a n z r a r u d o J Journal of Environmental Hazards ReviewResearch Article Article OpenOpen Access Access On the Possibility of Experimental Detection of Virtual Particles in Physical Vacuum Anatolii Pavlenko* Open International University of Human Development, Ukraine Abstract The article that you are about to read may surprise you because it looks at problems whose origin is little known and which are rarely taken into account. These problems are real and it is logical to think that the recent and large- scale multiplication of antennas and wind turbines with their earthing in pathogenic zones and the mobile telephony induce fields which modify the natural equilibrium of the soil and have effects on the biosphere. The development of new technologies, such as wind turbines or antennas, such as mobile telephony, induces new forms of pollution that spread through soil faults and can have a negative impact on the health of humans and animals. In the article we share our experience which led us to understand the link between some of these installations and the disorders observed in humans or animals. This is an attempt to change the presentation of the problem of protecting people from the negative impact of electronic technology in public opinion by explaining the reality of virtual particles and their impact on people. We are trying to widely discuss this propaganda about virtual particles. This is an attempt to deduce a discussion on the need to protect against the negative impact of electronic technology on the living in the realm of the radical. -
A Historical Review of the Discovery of the Quark and Gluon Jets
EPJ manuscript No. (will be inserted by the editor) JETS AND QCD: A Historical Review of the Discovery of the Quark and Gluon Jets and its Impact on QCD⋆ A.Ali1 and G.Kramer2 1 DESY, D-22603 Hamburg (Germany) 2 Universit¨at Hamburg, D-22761 Hamburg (Germany) Abstract. The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of hadrons, reflect configurations of quarks and gluons at short distances. Thus, by analysing energy and angular distributions of the jets experimentally, the properties of the basic constituents of matter and the strong forces acting between them can be explored. In this review, which is primarily a description of the discovery of the quark and gluon jets and the impact of their obser- vation on Quantum Chromodynamics, we elaborate, in particular, the role of the gluons as the carriers of the strong force. Focusing on these basic points, jets in e+e− collisions will be in the foreground of the discussion and we will concentrate on the theory that was contempo- rary with the relevant experiments at the electron-positron colliders. In addition we will delineate the role of jets as tools for exploring other particle aspects in ep and pp/pp¯ collisions - quark and gluon densi- ties in protons, measurements of the QCD coupling, fundamental 2-2 quark/gluon scattering processes, but also the impact of jet decays of top quarks, and W ±, Z bosons on the electroweak sector. -
Probing 23% of the Universe at the Large Hadron Collider
Probing 23% of the Universe at the Large Hadron Collider Will Flanagan1 Advisor: Dr Teruki Kamon2 In close collaboration with Bhaskar Dutta2, Alfredo Gurrola2, Nikolay Kolev3, Tom Crockett2, Michael VanDyke2, and Abram Krislock2 1University of Colorado at Boulder, Cyclotron REU Program 2Texas A&M University 3University of Regina Introduction What is cosmologically significant about ‘focus Analysis With recent astronomical measurements, point’? We first decide which events we want to look for. χ~0 ~0 we know that 23% of the Universe is The 1is allowed to annihilate with itself since it is Since χ 1 is undetectable (otherwise it wouldn’t be ‘dark composed of dark matter, whose origin is its own antimatter particle. The χ~ 0 -χ~0 annihilation matter’!), we look for events with a 1 1 Red – Jet distribution unknown. Supersymmetry (SUSY), a leading cross section is typically too small (predicting a relic after MET cut large amount of missing transverse theory in particle physics, provides us with a cold dark χ~0 Z channel dark matter density that is too energy. Also, due to the nature of 1 u- matter candidate, the lightest supersymmetric particle Z0 large). The small µ of focus these decays (shown below) we also χ~0 (LSP). SUSY particles, including the LSP, can be 1 u point x require two energetic jets. 2 f 1 Ω ~0 ~h dx created at the Large Hadron Collider (LHC) at CERN. allows for a larger annihilation χ1 ∫ 0 σ v { ann g~ 2 energetic jets + 2 leptons We perform a systematic study to characterize the cross section for our dark 0.23 698 u- + MET 2 g~ SUSY signals in the "focus point" region, one of a few matter candidate by opening πα ~ u - σ annv = 2 u l cosmologically-allowed parameter regions in our SUSY up the ‘Z channel’ (pictured 321 8M χ~0 l+ 0.9 pb 2 ~+ model. -
Virtual Particle 1 Virtual Particle
Virtual particle 1 Virtual particle In physics, a virtual particle is a transient fluctuation that exhibits many of the characteristics of an ordinary particle, but that exists for a limited time. The concept of virtual particles arises in perturbation theory of quantum field theory where interactions between ordinary particles are described in terms of exchanges of virtual particles. Any process involving virtual particles admits a schematic representation known as a Feynman diagram, in which virtual particles are represented by internal lines. [1][2] Virtual particles do not necessarily carry the same mass as the corresponding real particle, although they always conserve energy and momentum. The longer the virtual particle exists, the closer its characteristics come to those of ordinary particles. They are important in the physics of many processes, including particle scattering and Casimir forces. In quantum field theory, even classical forces — such as the electromagnetic repulsion or attraction between two charges — can be thought of as due to the exchange of many virtual photons between the charges. The term is somewhat loose and vaguely defined, in that it refers to the view that the world is made up of "real particles": it is not; rather, "real particles" are better understood to be excitations of the underlying quantum fields. Virtual particles are also excitations of the underlying fields, but are "temporary" in the sense that they appear in calculations of interactions, but never as asymptotic states or indices to the scattering matrix. As such the accuracy and use of virtual particles in calculations is firmly established, but their "reality" or existence is a question of philosophy rather than science. -
E+ E~ ANNIHILATION Hinrich Meyer, Fachbereich Physik, Universitдt
- 155 - e+e~ ANNIHILATION Hinrich Meyer, Fachbereich Physik, Universität Wuppertal, Fed. Rep. Germany CONTENT INTRODUCTION 1. e+e~ STORAGE RINGS .1 Energy and Size .2 Luminosity .3 Energy range of one Ring .4 Energie resolution .5 Polarization 2. EXPERIMENTAL PROCEDURES .1 Storage Ring Detectors .2 Background .3 Luminosity Measurement .4 Radiative Corrections 3. QED-REACTIONS + . 1 e+e~ T T~ .2 e+e"+y+y~ . 3 e+e~ -»• e+e~ . 4 e+e_ •+y y 4. HADRON PRODUCTION IN e+e~ANNTHILATION .1 Total Cross Section .2 Average Event Properties .3 Two Jet Structure .4 Three Jet Structure .5 Gluon Properties - 156 - 5. SEARCH FOR NEW PARTICLES .1 Experimental Methods .2 Search for the sixth Flavor (t) .3 Properties of Q Q Resonances .4 New Leptons 6. YY ~ REACTIONS .1 General Properties .2 Resonance Production .3 £ for e,Y Scattering .4 Hard Scattering Processes .5 Photon Structure Function INTRODUCTION e+e storage rings have been proven to be an extremely fruitful techno• logical invention for particle physics. They were originally designed to provide stringent experimental tests of the theory of leptons and photons QED (Quantum-Electro-Dynamics). QED has passed these tests beautifully up to the highest energies (PETRA) so far achieved. The great successes of the e+e storage rings however are in the field of strong interaction physics. The list below gives a very brief overview of the historical development by quoting the highlights of physics results from e+e storage rings with the completion of storage rings of higher and higher energy (see Fig.1). YEAR -
Model of N¯ Annihilation in Experimental Searches for N¯ Transformations
PHYSICAL REVIEW D 99, 035002 (2019) Model of n¯ annihilation in experimental searches for n¯ transformations E. S. Golubeva,1 J. L. Barrow,2 and C. G. Ladd2 1Institute for Nuclear Research, Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, Moscow, 117312, Russia 2University of Tennessee, Department of Physics, 401 Nielsen Physics Building, 1408 Circle Drive, Knoxville, Tennessee 37996, USA (Received 24 July 2018; published 5 February 2019) Searches for baryon number violation, including searches for proton decay and neutron-antineutron transformation (n → n¯), are expected to play an important role in the evolution of our understanding of beyond standard model physics. The n → n¯ is a key prediction of certain popular theories of baryogenesis, and experiments such as the Deep Underground Neutrino Experiment and the European Spallation Source plan to search for this process with bound- and free-neutron systems. Accurate simulation of this process in Monte Carlo will be important for the proper reconstruction and separation of these rare events from background. This article presents developments towards accurate simulation of the annihilation process for 12 use in a cold, free neutron beam for n → n¯ searches from nC¯ annihilation, as 6 C is the target of choice for the European Spallation Source’s NNBar Collaboration. Initial efforts are also made in this paper to 40 perform analogous studies for intranuclear transformation searches in 18Ar nuclei. DOI: 10.1103/PhysRevD.99.035002 I. INTRODUCTION evacuated, magnetically shielded pipe of 76 m in length (corresponding to a flight time of ∼0.1 s), until being A. Background 12 allowed to hit a target of carbon (6 C) foil (with a thickness As early as 1967, A. -
Quark Annihilation and Lepton Formation Versus Pair Production and Neutrino Oscillation: the Fourth Generation of Leptons
Volume 2 PROGRESS IN PHYSICS April, 2011 Quark Annihilation and Lepton Formation versus Pair Production and Neutrino Oscillation: The Fourth Generation of Leptons T. X. Zhang Department of Physics, Alabama A & M University, Normal, Alabama E-mail: [email protected] The emergence or formation of leptons from particles composed of quarks is still re- mained very poorly understood. In this paper, we propose that leptons are formed by quark-antiquark annihilations. There are two types of quark-antiquark annihilations. Type-I quark-antiquark annihilation annihilates only color charges, which is an incom- plete annihilation and forms structureless and colorless but electrically charged leptons such as electron, muon, and tau particles. Type-II quark-antiquark annihilation an- nihilates both electric and color charges, which is a complete annihilation and forms structureless, colorless, and electrically neutral leptons such as electron, muon, and tau neutrinos. Analyzing these two types of annihilations between up and down quarks and antiquarks with an excited quantum state for each of them, we predict the fourth gener- ation of leptons named lambda particle and neutrino. On the contrary quark-antiquark annihilation, a lepton particle or neutrino, when it collides, can be disintegrated into a quark-antiquark pair. The disintegrated quark-antiquark pair, if it is excited and/or changed in flavor during the collision, will annihilate into another type of lepton par- ticle or neutrino. This quark-antiquark annihilation and pair production scenario pro- vides unique understanding for the formation of leptons, predicts the fourth generation of leptons, and explains the oscillation of neutrinos without hurting the standard model of particle physics.