DOCSLIB.ORG

Mixing Particles Quark Compositions Are Their Own the Junction Could Be Enhanced Antiparticles

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mixing Particles Quark Compositions Are Their Own the Junction Could Be Enhanced Antiparticles The decay products of a pair of neutral B mesons formed in the disintegration of an upsilon (4S) resonance as observed by the ARGUS experiment at the DORIS electron-positron storage ring at the DESY Laboratory in Hamburg. This shows that the neutral B mesons and their antiparticles appear to mix. tures with a velocity of 104 cm/s. At the liquid helium surface, rotons have a 30% probability of evaporating a helium atom, so the problem of detecting one neu­ trino is transformed into the prob­ lem of detecting 107 to 108 eva­ porated helium atoms with bolo­ meters mounted above the liquid surface. The physics of the elec­ tron energy loss in liquid helium as well as the reflectivity of rotons from the liquid surface have to be further investigated. Norman Booth and his collabo­ rators from Cambridge and Queen Mary College have developed a novel indium detector for a solar ï(4S)-^B°B° neutrino experiment, having suc­ cessfully worked out a method to grow indium crystals over super­ conducting tunnel junctions. The energy released when a solar neu­ BO -p^*- + trino is captured in indium is mostly transformed into phonons. These TTl D° »rr D" can break up Cooper pairs in the junction, leading to quasiparticles. >K27T27T2 The tunnel junction acts as a semi­ permeable membrane letting the quasiparticles pass, thus giving rise to a signal current, albeit very small. However the sensitivity of Mixing particles quark compositions are their own the junction could be enhanced antiparticles. considerably by trapping the qua­ The ARGUS experiment (a DESY / Other electrically neutral mesons siparticles in another superconduc­ Dortmund / Heidelberg / IPP Ca­ are distinguished from their anti­ tor of lower gap in the region of nada / Kansas / Ljubljana / Lund / particles by a quark label (quantum the tunnel junction. If the relative Moscow / South Carolina /Stock­ number) which is only conserved gap energies are right, a multipli­ holm collaboration) at the DORIS II in strong nuclear interactions. cation process can occur, leading electron-positron collider at the When the weak nuclear force is to a'quasiparticle multiplier'. German DESY Laboratory in Ham­ in action, these quantum numbers The workshop showed that burg has provided valuable new are no longer conserved and inter­ while these innovations still require evidence for particle 'mixing'. esting things can happen. a lot of work, enthusiasm is high Every particle of matter has an For example the neutral kaon and the potential physics rewards antimatter counterpart, or antipar- and its antiparticle are distin­ are large. Next year's workshop ticle, carrying equal but opposite guished by the strong interaction at LAPP (Annecy) will show how quantum numbers. For mesons, label of strangeness. This is not much progress has been made. composed of quark-antiquark pairs, conserved in weak interactions, the antiparticles have the corre­ so that the neutral kaon and its From Klaus Pretzl sponding antiquark-quark configu­ antiparticle get mixed up. ration. Thus mesons (like neutral Additional symmetries, such as pions) with symmetric quark-anti­ combined particle-antiparticle 16 CERN Courier, June 1987 switching and space reflection (CP) sitive to background, consisted of mally this (spin-orbit) coupling is become useful, and the neutral reconstructing one neutral B meson very small, about a thousandth of kaons provide a rich scenario for and tagging the second by the an electronvolt at 10tesla the subtleties of the weak force. charge of an accompanying ener­ (100 kgauss). Last year the UA1 experiment getic lepton. Five mixing candi­ If a particle is relativistic (travell­ at CERN's proton-antiproton col­ dates were found, where only ing with a velocity comparable to lider provided evidence for an ana­ about one was expected due to that of light), it experiences a highly logous mixing of the neutral background, again a suggestive velocity-dependent field. Thus if B mesons (see October 1986 signal. an electron moves so fast that the issue, page 17). In today's 'Standard Model', six magnetic field it 'sees' reaches Neutral B mesons exist in two varieties of quark are grouped into about 4 x 109tesla, the energy varieties, with and without strange three doublets (up and down, due to spin alignment becomes quarks. The lighter non-strange strange and charm, beauty and comparable to the electron's mass, particles can be isolated by looking top), and all the corresponding and interesting effects become below the threshold for production quantum number changes pro­ possible. of the strange quark variety. duced by the weak force are des­ Using external fields, even high The ARGUS experiment studied cribed by the 'Kobayashi-Maska- energy beams from a particle the formation of neutral non- wa' (KM) matrix. As yet no theory accelerator do not reach these strange B meson pairs coming gives all the parameters of this thresholds (a 10 T field would from the decay of upsilon reson­ matrix, but predictions can need an electron beam of ances (the 4S state at 10.6 GeV). be made using input from 250000 GeV!). However higher Great importance was attached to experiments. macroscopic fields are supplied particle identification, and from The relatively large rate of mixing along axial directions inside crys­ data collected over five years of seen by ARGUS provides more tals. With these very strong fields running evidence for mixing is input to this matrix, and indicates interesting quantum phenomena found in three different ways. that the as yet unseen top quark should become possible. Firstly, from 88 000 upsilon (4S) is heavier than about 50 GeV. If These effects have been studied events analysed, one example is this is correct, mesons consisting in a series of experiments at CERN found of an explicitly mixed decay of top quark-antiquark pairs would by researchers from Albany (New into two neutral B mesons (rather occur near 100 GeV, out of reach York), Annecy and Lyon. 150 GeV than a neutral B and its antiparti­ of the new TRISTAN electron- electron and photon beams were cle). All the B decay products (oth­ positron collider at the Japanese injected along an axis of an er than neutrinos) are fully identi­ KEK Laboratory. 0.2 mm-thick germanium crystal fied and the event is very clean. B mixing limits also come from cooled to 100 K with an angular The neutral B mesons sub­ other experiments at electron-posi­ spread of about 25 microradians. sequently decay in a variety of tron colliders at Stanford, Cornell Physicists saw a spectacular ways, emitting leptons (electrons and DESY. increase in the photoproduction or muons). The ratio of positively of electron-positron pairs at perfect charged to negatively charged lep­ alignment, not due to the reinforce­ tons is an indicator of mixing, and ment (coherence) of the interac­ the ARGUS group went about a Encounters with tions at different sites in the crys­ careful analysis of their electron strong fields tal, but to an interaction of photons and/or muon pairs. with the very strong field. Starting After painstaking elimination of A series of experiments at CERN at a photon threshold energy of backgrounds, they found some using high energy beams and crys­ 30 GeV, the effect eventually at­ 25 lepton pairs carrying two equal tal targets show some interesting tained ten times the level resulting electric charges, compared with quantum effects. from (incoherent) background ef­ 270 carrying opposite charges. The energy of an electron in an fects using an unaligned crystal. This gives a B meson mixing para­ external field depends on whether Further studies of the effect of meter in the region of 20 per cent. it lines up spinning parallel or anti- the strong crystal field on the elec­ Another method used, less sen­ parallel to the field direction. Nor­ tron beam showed an intense nar- CERN Courier, June 1987 17 .
Load more

Recommended publications
  • (Anti)Proton Mass and Magnetic Moment
    FFK Conference 2019, Tihany, Hungary Precision measurements of the (anti)proton mass and magnetic moment Wolfgang Quint GSI Darmstadt and University of Heidelberg on behalf of the BASE collaboration spokesperson: Stefan Ulmer 2019 / 06 / 12 BASE – Collaboration • Mainz: Measurement of the magnetic moment of the proton, implementation of new technologies. • CERN Antiproton Decelerator: Measurement of the magnetic moment of the antiproton and proton/antiproton q/m ratio • Hannover/PTB: Laser cooling project, new technologies Institutes: RIKEN, MPI-K, CERN, University of Mainz, Tokyo University, GSI Darmstadt, University of Hannover, PTB Braunschweig C. Smorra et al., EPJ-Special Topics, The BASE Experiment, (2015) WE HAVE A PROBLEM mechanism which created the obvious baryon/antibaryon asymmetry in the Universe is not understood One strategy: Compare the fundamental properties of matter / antimatter conjugates with ultra-high precision CPT tests based on particle/antiparticle comparisons R.S. Van Dyck et al., Phys. Rev. Lett. 59 , 26 (1987). Recent B. Schwingenheuer, et al., Phys. Rev. Lett. 74, 4376 (1995). Past CERN H. Dehmelt et al., Phys. Rev. Lett. 83 , 4694 (1999). G. W. Bennett et al., Phys. Rev. D 73 , 072003 (2006). Planned M. Hori et al., Nature 475 , 485 (2011). ALICE G. Gabriesle et al., PRL 82 , 3199(1999). J. DiSciacca et al., PRL 110 , 130801 (2013). S. Ulmer et al., Nature 524 , 196-200 (2015). ALICE Collaboration, Nature Physics 11 , 811–814 (2015). M. Hori et al., Science 354 , 610 (2016). H. Nagahama et al., Nat. Comm. 8, 14084 (2017). M. Ahmadi et al., Nature 541 , 506 (2017). M. Ahmadi et al., Nature 586 , doi:10.1038/s41586-018-0017 (2018).
    [Show full text]
  • Interactions of Antiprotons with Atoms and Molecules
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln US Department of Energy Publications U.S. Department of Energy 1988 INTERACTIONS OF ANTIPROTONS WITH ATOMS AND MOLECULES Mitio Inokuti Argonne National Laboratory Follow this and additional works at: https://digitalcommons.unl.edu/usdoepub Part of the Bioresource and Agricultural Engineering Commons Inokuti, Mitio, "INTERACTIONS OF ANTIPROTONS WITH ATOMS AND MOLECULES" (1988). US Department of Energy Publications. 89. https://digitalcommons.unl.edu/usdoepub/89 This Article is brought to you for free and open access by the U.S. Department of Energy at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in US Department of Energy Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. /'Iud Tracks Radial. Meas., Vol. 16, No. 2/3, pp. 115-123, 1989 0735-245X/89 $3.00 + 0.00 Inl. J. Radial. Appl .. Ins/rum., Part D Pergamon Press pic printed in Great Bntam INTERACTIONS OF ANTIPROTONS WITH ATOMS AND MOLECULES* Mmo INOKUTI Argonne National Laboratory, Argonne, Illinois 60439, U.S.A. (Received 14 November 1988) Abstract-Antiproton beams of relatively low energies (below hundreds of MeV) have recently become available. The present article discusses the significance of those beams in the contexts of radiation physics and of atomic and molecular physics. Studies on individual collisions of antiprotons with atoms and molecules are valuable for a better understanding of collisions of protons or electrons, a subject with many applications. An antiproton is unique as' a stable, negative heavy particle without electronic structure, and it provides an excellent opportunity to study atomic collision theory.
    [Show full text]
  • 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]
  • BOTTOM, STRANGE MESONS (B = ±1, S = ∓1) 0 0 ∗ Bs = Sb, Bs = S B, Similarly for Bs ’S
    Citation: P.A. Zyla et al. (Particle Data Group), Prog. Theor. Exp. Phys. 2020, 083C01 (2020) BOTTOM, STRANGE MESONS (B = ±1, S = ∓1) 0 0 ∗ Bs = sb, Bs = s b, similarly for Bs ’s 0 P − Bs I (J ) = 0(0 ) I , J, P need confirmation. Quantum numbers shown are quark-model predictions. Mass m 0 = 5366.88 ± 0.14 MeV Bs m 0 − mB = 87.38 ± 0.16 MeV Bs Mean life τ = (1.515 ± 0.004) × 10−12 s cτ = 454.2 µm 12 −1 ∆Γ 0 = Γ 0 − Γ 0 = (0.085 ± 0.004) × 10 s Bs BsL Bs H 0 0 Bs -Bs mixing parameters 12 −1 ∆m 0 = m 0 – m 0 = (17.749 ± 0.020) × 10 ¯h s Bs Bs H BsL = (1.1683 ± 0.0013) × 10−8 MeV xs = ∆m 0 /Γ 0 = 26.89 ± 0.07 Bs Bs χs = 0.499312 ± 0.000004 0 CP violation parameters in Bs 2 −3 Re(ǫ 0 )/(1+ ǫ 0 )=(−0.15 ± 0.70) × 10 Bs Bs 0 + − CKK (Bs → K K )=0.14 ± 0.11 0 + − SKK (Bs → K K )=0.30 ± 0.13 0 ∓ ± +0.10 rB(Bs → Ds K )=0.37−0.09 0 ± ∓ ◦ δB(Bs → Ds K ) = (358 ± 14) −2 CP Violation phase βs = (2.55 ± 1.15) × 10 rad λ (B0 → J/ψ(1S)φ)=1.012 ± 0.017 s λ = 0.999 ± 0.017 A, CP violation parameter = −0.75 ± 0.12 C, CP violation parameter = 0.19 ± 0.06 S, CP violation parameter = 0.17 ± 0.06 L ∗ 0 ACP (Bs → J/ψ K (892) ) = −0.05 ± 0.06 k ∗ 0 ACP (Bs → J/ψ K (892) )=0.17 ± 0.15 ⊥ ∗ 0 ACP (Bs → J/ψ K (892) ) = −0.05 ± 0.10 + − ACP (Bs → π K ) = 0.221 ± 0.015 0 + − ∗ 0 ACP (Bs → [K K ]D K (892) ) = −0.04 ± 0.07 HTTP://PDG.LBL.GOV Page1 Created:6/1/202008:28 Citation: P.A.
    [Show full text]
  • Energy-Dependent Kinetic Model of Photon Absorption by Superconducting Tunnel Junctions
    Energy-dependent kinetic model of photon absorption by superconducting tunnel junctions G. Brammertz Science Payload and Advanced Concepts Office, ESA/ESTEC, Postbus 299, 2200AG Noordwijk, The Netherlands. A. G. Kozorezov, J. K. Wigmore Department of Physics, Lancaster University, Lancaster, United Kingdom. R. den Hartog, P. Verhoeve, D. Martin, A. Peacock Science Payload and Advanced Concepts Office, ESA/ESTEC, Postbus 299, 2200AG Noordwijk, The Netherlands. A. A. Golubov, H. Rogalla Department of Applied Physics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. Received: 02 June 2003 – Accepted: 31 July 2003 Abstract – We describe a model for photon absorption by superconducting tunnel junctions in which the full energy dependence of all the quasiparticle dynamic processes is included. The model supersedes the well-known Rothwarf-Taylor approach, which becomes inadequate for a description of the small gap structures that are currently being developed for improved detector resolution and responsivity. In these junctions relaxation of excited quasiparticles is intrinsically slow so that the energy distribution remains very broad throughout the whole detection process. By solving the energy- dependent kinetic equations describing the distributions, we are able to model the temporal and spectral evolution of the distribution of quasiparticles initially generated in the photo-absorption process. Good agreement is obtained between the theory and experiment. PACS numbers: 85.25.Oj, 74.50.+r, 74.40.+k, 74.25.Jb To be published in the November issue of Journal of Applied Physics 1 I. Introduction The development of superconducting tunnel junctions (STJs) for application as photon detectors for astronomy and materials analysis continues to show great promise1,2.
    [Show full text]
  • Vortices and Quasiparticles in Superconducting Microwave Resonators
    Syracuse University SURFACE Dissertations - ALL SURFACE May 2016 Vortices and Quasiparticles in Superconducting Microwave Resonators Ibrahim Nsanzineza Syracuse University Follow this and additional works at: https://surface.syr.edu/etd Part of the Physical Sciences and Mathematics Commons Recommended Citation Nsanzineza, Ibrahim, "Vortices and Quasiparticles in Superconducting Microwave Resonators" (2016). Dissertations - ALL. 446. https://surface.syr.edu/etd/446 This Dissertation is brought to you for free and open access by the SURFACE at SURFACE. It has been accepted for inclusion in Dissertations - ALL by an authorized administrator of SURFACE. For more information, please contact [email protected]. Abstract Superconducting resonators with high quality factors are of great interest in many areas. However, the quality factor of the resonator can be weakened by many dissipation chan- nels including trapped magnetic flux vortices and nonequilibrium quasiparticles which can significantly impact the performance of superconducting microwave resonant circuits and qubits at millikelvin temperatures. Quasiparticles result in excess loss, reducing resonator quality factors and qubit lifetimes. Vortices trapped near regions of large mi- crowave currents also contribute excess loss. However, vortices located in current-free areas in the resonator or in the ground plane of a device can actually trap quasiparticles and lead to a reduction in the quasiparticle loss. In this thesis, we will describe exper- iments involving the controlled trapping of vortices for reducing quasiparticle density in the superconducting resonators. We provide a model for the simulation of reduc- tion of nonequilibrium quasiparticles by vortices. In our experiments, quasiparticles are generated either by stray pair-breaking radiation or by direct injection using normal- insulator-superconductor (NIS)-tunnel junctions.
    [Show full text]
  • Coupling Experiment and Simulation to Model Non-Equilibrium Quasiparticle Dynamics in Superconductors
    Coupling Experiment and Simulation to Model Non-Equilibrium Quasiparticle Dynamics in Superconductors A. Agrawal9, D. Bowring∗1, R. Bunker2, L. Cardani3, G. Carosi4, C.L. Chang15, M. Cecchin1, A. Chou1, G. D’Imperio3, A. Dixit9, J.L DuBois4, L. Faoro16,7, S. Golwala6, J. Hall13,14, S. Hertel12, Y. Hochberg11, L. Ioffe5, R. Khatiwada1, E. Kramer11, N. Kurinsky1, B. Lehmann10, B. Loer2, V. Lordi4, R. McDermott7, J.L. Orrell2, M. Pyle17, K. G. Ray4, Y. J. Rosen4, A. Sonnenschein1, A. Suzuki8, C. Tomei3, C. Wilen7, and N. Woollett4 1Fermi National Accelerator Laboratory 2Pacific Northwest National Laboratory 3Sapienza University of Rome 4Lawrence Livermore National Laboratory 5Google, Inc. 6California Institute of Technology 7University of Wisconsin, Madison 8Lawrence Berkeley National Laboratory 9University of Chicago 10University of California, Santa Cruz 11Hebrew University of Jerusalem 12University of Massachusetts, Amherst 13SNOLAB 14Laurentian University 15Argonne National Laboratory 16Laboratoire de Physique Therique et Hautes Energies, Sorbornne Universite 17University of California, Berkeley August 31, 2020 Thematic Areas: (check all that apply /) (CF1) Dark Matter: Particle Like (CF2) Dark Matter: Wavelike (IF1) Quantum Sensors (IF2) Photon Detectors (IF9) Cross Cutting and Systems Integration (UF02) Underground Facilities for Cosmic Frontier (UF05) Synergistic Research ∗Corresponding author: [email protected] 1 Abstract In superconducting devices, broken Cooper pairs (quasiparticles) may be considered signal (e.g., transition edge sensors, kinetic inductance detectors) or noise (e.g., quantum sensors, qubits). In order to improve design for these devices, a better understanding of quasiparticle production and transport is required. We propose a multi-disciplinary collaboration to perform measurements in low-background facilities that will be used to improve modeling and simulation tools, suggest new measurements, and drive the design of future improved devices.
    [Show full text]
  • 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.
    [Show full text]
  • "Normal-Metal Quasiparticle Traps for Superconducting Qubits"
    Normal-Metal Quasiparticle Traps For Superconducting Qubits: Modeling, Optimization, and Proximity Effect Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der RWTH Aachen University zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften genehmigte Dissertation vorgelegt von Amin Hosseinkhani, M.Sc. Berichter: Universitätsprofessor Dr. David DiVincenzo, Universitätsprofessorin Dr. Kristel Michielsen Tag der mündlichen Prüfung: March 01, 2018 Diese Dissertation ist auf den Internetseiten der Universitätsbibliothek online verfügbar. Metallische Quasiteilchenfallen für supraleitende Qubits: Modellierung, Optimisierung, und Proximity-Effekt Kurzfassung: Bogoliubov Quasiteilchen stören viele Abläufe in supraleitenden Elementen. In supraleitenden Qubits wechselwirken diese Quasiteilchen beim Tunneln durch den Josephson- Kontakt mit dem Phasenfreiheitsgrad, was zu einer Relaxation des Qubits führt. Für Tempera- turen im Millikelvinbereich gibt es substantielle Hinweise für die Präsenz von Nichtgleichgewicht- squasiteilchen. Während deren Entstehung noch nicht einstimmig geklärt ist, besteht dennoch die Möglichkeit die von Quasiteilchen induzierte Relaxation einzudämmen indem man die Qu- asiteilchen von den aktiven Bereichen des Qubits fernhält. In dieser Doktorarbeit studieren wir Quasiteilchenfallen, welche durch einen Kontakt eines normalen Metalls (N) mit der supraleit- enden Elektrode (S) eines Qubits definiert sind. Wir entwickeln ein Modell, das den Einfluss der Falle auf die Quasiteilchendynamik beschreibt,
    [Show full text]
  • ANTIMATTER a Review of Its Role in the Universe and Its Applications
    A review of its role in the ANTIMATTER universe and its applications THE DISCOVERY OF NATURE’S SYMMETRIES ntimatter plays an intrinsic role in our Aunderstanding of the subatomic world THE UNIVERSE THROUGH THE LOOKING-GLASS C.D. Anderson, Anderson, Emilio VisualSegrè Archives C.D. The beginning of the 20th century or vice versa, it absorbed or emitted saw a cascade of brilliant insights into quanta of electromagnetic radiation the nature of matter and energy. The of definite energy, giving rise to a first was Max Planck’s realisation that characteristic spectrum of bright or energy (in the form of electromagnetic dark lines at specific wavelengths. radiation i.e. light) had discrete values The Austrian physicist, Erwin – it was quantised. The second was Schrödinger laid down a more precise that energy and mass were equivalent, mathematical formulation of this as described by Einstein’s special behaviour based on wave theory and theory of relativity and his iconic probability – quantum mechanics. The first image of a positron track found in cosmic rays equation, E = mc2, where c is the The Schrödinger wave equation could speed of light in a vacuum; the theory predict the spectrum of the simplest or positron; when an electron also predicted that objects behave atom, hydrogen, which consists of met a positron, they would annihilate somewhat differently when moving a single electron orbiting a positive according to Einstein’s equation, proton. However, the spectrum generating two gamma rays in the featured additional lines that were not process. The concept of antimatter explained. In 1928, the British physicist was born.
    [Show full text]
  • Quasi-Dirac Monopoles
    research highlights Defective yet strong fundamental particle, the magnetic polymeric film, the researchers embedded Nature Commun. 5, 3186 (2014) monopole, with non-zero magnetic silver nanoparticles that have a localized monopole charge, has grasped the attention surface plasmon resonance in the blue With a tensile strength of over 100 GPa, of many. The existence of magnetic spectral range; the fabricated film therefore a pristine graphene layer is the strongest monopoles is now not only supported by the scatters this colour while being almost material known. However, most graphene work of Dirac, but by both the grand unified completely transparent in the remaining fabrication processes inevitably produce theory and string theory. However, both visible spectral range. The researchers a defective layer. Also, structural defects theories realize that magnetic monopoles suggest that dispersion in a single matrix of are desirable in some of the material’s might be too few and too massive to be metallic nanoparticles with sharp plasmonic technological applications, as defects allow detected or created in a lab, so physicists resonances tuned at different wavelengths for the opening of a bandgap or act as pores started to explore approaches to obtain will lead to the realization of multicoloured for molecular sieving, for example. Now, by such particles using condensed-matter transparent displays. LM tuning the exposure of graphene to oxygen systems. Now, Ray and co-workers report plasma to control the creation of defects, the latest observation of a Dirac monopole Ardavan Zandiatashbar et al. show that a quasiparticle (pictured), this time in a Facet formation Adv. Mater. http://doi.org/rb5 (2014) single layer of graphene bearing sp3-type spinor Bose–Einstein condensate.
    [Show full text]
  • Strange Hadrocharmonium ∗ M.B
    Physics Letters B 798 (2019) 135022 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb Strange hadrocharmonium ∗ M.B. Voloshin a,b,c, a William I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, MN 55455, USA b School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA c Institute of Theoretical and Experimental Physics, Moscow, 117218, Russia a r t i c l e i n f o a b s t r a c t Article history: It has been recently suggested that the charged charmoniumlike resonances Zc (4100) and Zc (4200) Received 23 May 2019 are two states of hadrocharmonium, related by the charm quark spin symmetry in the same way Received in revised form 12 August 2019 as the lowest charmonium states ηc and J/ψ. It is pointed out here that in this picture one might Accepted 16 September 2019 expect existence of their somewhat heavier strange counterparts, Zcs, decaying to ηc K and J/ψ K . Some Available online 11 October 2019 expected properties of such charmoniumlike strange resonances are discussed that set benchmarks for Editor: B. Grinstein their search in the decays of the strange Bs mesons. © 2019 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license 3 (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP . Numerous new resonances recently uncovered near the open down to about 4220 MeV), has been recently invoked [11]for de- charm and open bottom thresholds, the so-called XYZ states, ap- scription of the charged charmoniumlike resonances Zc(4100) and parently do not fit in the standard quark-antiquark template and Zc(4200) observed respectively in the decay channels ηcπ [12] 1 contain light constituents in addition to a heavy quark-antiquark and J/ψπ [13].
    [Show full text]