DOCSLIB.ORG

Gluons Keep Protons and Neutrons Intact— and Thereby Hold the Universe Together

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gluons Keep Protons and Neutrons Intact— and Thereby Hold the Universe Together PARTICLE PHYSICS the glue bındsthat Physicists have knownus for decades that particles called gluons keep protons and neutrons intact— and thereby hold the universe together. Yet the details of how gluons function remain surprisingly mysterious By Rolf Ent, Thomas Ullrich and Raju Venugopalan 42 Scientific American, May 2015 Illustration by Maria Corte May 2015, ScientificAmerican.com 43 Rolf Ent has worked at the Thomas Jefferson National Accelerator Facility in Newport News, Va., since 1993. He is associate director of experimental nuclear physics there and has been a spokesperson for multiple experiments studying the quark-gluon structure of hadrons and atomic nuclei. Thomas Ullrich joined Brookhaven National Laboratory in 2001 and also conducts research and teaches at Yale University. He has partici- pated in several experiments, first at CERN near Geneva and later at Brookhaven, to search for and study the quark-gluon plasma. His recent efforts focus on the realization of an electron-ion collider. Raju Venugopalan heads the Nuclear Theory Group at Brookhaven National Laboratory, where he studies the interactions of quarks and gluons at high energies. he ancient Greeks believed atoms were the smallest bits of matter in the universe. Then scientists in the 20th century split the atom, yielding tinier ingredients: protons, neutrons and electrons. Pro- tons and neutrons, in turn, were shown to consist of smaller parti- cles called quarks, bound together by “sticky” particles, the appro- priately named gluons. These particles, we now know, are truly fundamental, but even this picture turns out to be incomplete. Experimental methods for peering inside protons and neu- the smaller particles’ spins do not easily add up to the whole. trons reveal a full-fledged symphonic orchestra within. These If physicists could answer these questions, we would finally particles each consist of three quarks and varying numbers of begin to comprehend how matter functions at its most funda- gluons, along with what are called sea quarks—pairs of quarks mental level. Identifying the main enigmas surrounding quarks Taccompanied by their antimatter partners, antiquarks—which and gluons, which we will detail below, is itself a key step toward appear and disappear continuously. And protons and neutrons discerning the physics of matter at its finest levels. Ongoing and are not the only particles made of quarks found in the universe. future work, including studies focused on exotic configurations Accelerator experiments in the past half a century have created of quarks and gluons, should help demystify the puzzles. With a a host of other particles containing quarks and antiquarks, little luck, we will soon be able to break out of the fog. which, together with protons and neutrons, are called hadrons. Despite all this insight—and a good understanding of how WHERE DOES PROTON MASS COME FROM? individual quarks and gluons interact with one another—physi- the mystery of mass is one of physicists’ most vexing questions cists, to our dismay, cannot fully explain how quarks and gluons and offers a good sense of why the workings of quarks and gluons generate the full range of properties and behaviors displayed by are so perplexing. We have a pretty good grasp of how quarks and protons, neutrons and other hadrons. For example, adding up leptons—a category of particles that includes electrons—get their the masses of the quarks and gluons inside protons does not mass. The mechanism arises from the Higgs boson—the particle begin to account for the total masses of protons, raising the puz- discovered to much fanfare at the Large Hadron Collider (LHC) zle of where all this missing mass comes from. Further, we won- at CERN near Geneva in 2012—and from its associated Higgs der how exactly gluons do the work of binding quarks in the first field, which pervades all of space. When particles pass through place and why this binding seems to rely on a special type of “col- this field, their interactions with it imbue them with mass. The or” charge within quarks. We also do not understand how a pro- Higgs mechanism is often said to account for the origin of mass ton’s rotation—a measurable quantity called spin—arises from in the visible universe. This statement, however, is incorrect. The the spins of the quarks and gluons inside it: a mystery because mass of quarks accounts for only 2 percent of the mass of the pro- IN BRIEF The matter that forms our world is fun- in understanding the workings of quarks and neutrons in atoms, for example, or Future experiments revealing the build- damentally made of particles called and gluons, but a number of puzzling how they give those particles spin. And ing blocks of matter in greater detail quarks that are held together by sticky mysteries remain. quarks and gluons seem to have a than ever before could help physicists particles, the appropriately named glu- It is unclear how quarks and gluons strange “color” charge, yet protons and better understand how quarks and glu- ons. Physicists have made huge strides contribute to the mass of the protons neutrons have no color. ons interact. 44 Scientific American, May 2015 ton and the neutron, respectively. The oth- NATURE’S BUILDING BLOCKS er 98 percent, we think, arises largely from the actions of gluons. But how glu- ons help to generate proton and neutron Fundamental Particles mass is not evident, because they are The nuclei inside all the atoms of the universe primarily con- Spin Electric themselves massless. tain just two of the known fundamental particles: quarks and charge A clue to resolving this conundrum is gluons. Gluons belong to a category called bosons ( right ), provided by Albert Einstein’s famous which, with the exception of the Higgs, carry nature’s forces. equation relating a particle’s mass at rest Particle Gluons transmit the most powerful of all the forces—the name to its energy. By inverting the equation to strong force, responsible for binding together quarks inside 2 read m = E/c , we see that the mass ( m) of protons and neutrons. Besides bosons, the other known fun- the proton at rest can be said to arise from Mass (in mega- damental particles in the universe are classified as fermions electron-volts) its energy ( E), expressed in units of the ( left ), which include leptons such as the electron, and quarks. speed of light (c ). Because the energy of a Quarks come in six types, but only the up and down fla- proton is mostly contributed by gluons, in vors—the ingredients of protons and neutrons—are found in theory, one would only need to figure out abundance in nature. the net energy of gluons to calculate the 1 0 proton’s mass. Photon (electro mag- Calculating the energy of gluons is dif- netism) ficult, however, in part because their total Generation I Generation II Generation III energy arises from several contributing 0 factors. The energy of a free particle (un­­ 1/2 +2/3 1/2 +2/3 1/2 +2/3 attached to others) is its energy of motion. 1 0 Yet quarks and gluons almost never exist Up Charm Top Gluon in isolation. They survive as free particles (strong only on unimaginably small timescales force) –24 seconds) before they 2.3 1,275 ~173,500 (less than 3 × 10 0 are bound up into other subatomic parti- Quarks 1/2 –1/3 1/2 –1/3 1/2 –1/3 cles and literally screened from view. 1 0 Moreover, in gluons, energy comes not Down Strange Bottom Z merely from motion; it is inseparable from (weak the energy they expend in binding them- force) BOSONS selves and quarks together into longer- 4.8 95 4,180 91,188 lived particles. Solving the mystery of mass therefore requires a better under- 1/2 0 1/2 0 1/2 0 FERMIONS 1 +1 standing of how gluons “glue.” But here, – Electron Muon Tau W too, gluons throw up roadblocks to deci- neutrino neutrino neutrino (weak phering their mysteries. force) < 0.000002 < 0.19 < 18.2 80,385 HOW DO GLUONS BIND? on one level, the answer to how gluons Leptons 1/2 –1 1/2 –1 1/2 –1 glue is simple: they wield the strong force. 0 0 But this force is itself puzzling. Electron Muon Tau Higgs The strong force is one of the four fun- damental forces of nature, along with 0.511 105.7 1,776.8 gravitation, electromagnetism and the ~125,000 weak force (the last responsible for radio- Increasing fermion mass active decay). Of these four, it is the most powerful by far (hence its name). In addi- tion to binding quarks together to form hadrons, the strong force is what binds protons and neutrons range of a force is inversely proportional to the mass of its force into atomic nuclei, overcoming the enormous electromagnetic carriers. The electromagnetic force, for example, has an infinite repulsion that exists between like-charged protons in a nucleus. range; a free electron on Earth will, in principle, experience a Each of nature’s fundamental forces appears to be tied to a parti- slight repulsion from an electron on the other side of the moon. cle, a so-called force carrier. Just as the photon—the fundamen- Photons, which carry the force between the electrons, are there- tal unit of light—is the force carrier of electromagnetism, the fore massless. In contrast to electromagnetism, the range of the gluon is the carrier of the strong force. strong force does not extend outside the nuclei of atoms. This So far so good. But the strong force sometimes acts in sur- fact would imply that gluons are very massive.
Load more

Recommended publications
  • The Five Common Particles
    The Five Common Particles The world around you consists of only three particles: protons, neutrons, and electrons. Protons and neutrons form the nuclei of atoms, and electrons glue everything together and create chemicals and materials. Along with the photon and the neutrino, these particles are essentially the only ones that exist in our solar system, because all the other subatomic particles have half-lives of typically 10-9 second or less, and vanish almost the instant they are created by nuclear reactions in the Sun, etc. Particles interact via the four fundamental forces of nature. Some basic properties of these forces are summarized below. (Other aspects of the fundamental forces are also discussed in the Summary of Particle Physics document on this web site.) Force Range Common Particles It Affects Conserved Quantity gravity infinite neutron, proton, electron, neutrino, photon mass-energy electromagnetic infinite proton, electron, photon charge -14 strong nuclear force ≈ 10 m neutron, proton baryon number -15 weak nuclear force ≈ 10 m neutron, proton, electron, neutrino lepton number Every particle in nature has specific values of all four of the conserved quantities associated with each force. The values for the five common particles are: Particle Rest Mass1 Charge2 Baryon # Lepton # proton 938.3 MeV/c2 +1 e +1 0 neutron 939.6 MeV/c2 0 +1 0 electron 0.511 MeV/c2 -1 e 0 +1 neutrino ≈ 1 eV/c2 0 0 +1 photon 0 eV/c2 0 0 0 1) MeV = mega-electron-volt = 106 eV. It is customary in particle physics to measure the mass of a particle in terms of how much energy it would represent if it were converted via E = mc2.
    [Show full text]
  • Fundamentals of Particle Physics
    Fundamentals of Par0cle Physics Particle Physics Masterclass Emmanuel Olaiya 1 The Universe u The universe is 15 billion years old u Around 150 billion galaxies (150,000,000,000) u Each galaxy has around 300 billion stars (300,000,000,000) u 150 billion x 300 billion stars (that is a lot of stars!) u That is a huge amount of material u That is an unimaginable amount of particles u How do we even begin to understand all of matter? 2 How many elementary particles does it take to describe the matter around us? 3 We can describe the material around us using just 3 particles . 3 Matter Particles +2/3 U Point like elementary particles that protons and neutrons are made from. Quarks Hence we can construct all nuclei using these two particles -1/3 d -1 Electrons orbit the nuclei and are help to e form molecules. These are also point like elementary particles Leptons We can build the world around us with these 3 particles. But how do they interact. To understand their interactions we have to introduce forces! Force carriers g1 g2 g3 g4 g5 g6 g7 g8 The gluon, of which there are 8 is the force carrier for nuclear forces Consider 2 forces: nuclear forces, and electromagnetism The photon, ie light is the force carrier when experiencing forces such and electricity and magnetism γ SOME FAMILAR THE ATOM PARTICLES ≈10-10m electron (-) 0.511 MeV A Fundamental (“pointlike”) Particle THE NUCLEUS proton (+) 938.3 MeV neutron (0) 939.6 MeV E=mc2. Einstein’s equation tells us mass and energy are equivalent Wave/Particle Duality (Quantum Mechanics) Einstein E
    [Show full text]
  • Introduction to Particle Physics
    SFB 676 – Projekt B2 Introduction to Particle Physics Christian Sander (Universität Hamburg) DESY Summer Student Lectures – Hamburg – 20th July '11 Outline ● Introduction ● History: From Democrit to Thomson ● The Standard Model ● Gauge Invariance ● The Higgs Mechanism ● Symmetries … Break ● Shortcomings of the Standard Model ● Physics Beyond the Standard Model ● Recent Results from the LHC ● Outlook Disclaimer: Very personal selection of topics and for sure many important things are left out! 20th July '11 Introduction to Particle Physics 2 20th July '11 Introduction to Particle PhysicsX Files: Season 2, Episode 233 … für Chester war das nur ein Weg das Geld für das eigentlich theoretische Zeugs aufzubringen, was ihn interessierte … die Erforschung Dunkler Materie, …ähm… Quantenpartikel, Neutrinos, Gluonen, Mesonen und Quarks. Subatomare Teilchen Die Geheimnisse des Universums! Theoretisch gesehen sind sie sogar die Bausteine der Wirklichkeit ! Aber niemand weiß, ob sie wirklich existieren !? 20th July '11 Introduction to Particle PhysicsX Files: Season 2, Episode 234 The First Particle Physicist? By convention ['nomos'] sweet is sweet, bitter is bitter, hot is hot, cold is cold, color is color; but in truth there are only atoms and the void. Democrit, * ~460 BC, †~360 BC in Abdera Hypothesis: ● Atoms have same constituents ● Atoms different in shape (assumption: geometrical shapes) ● Iron atoms are solid and strong with hooks that lock them into a solid ● Water atoms are smooth and slippery ● Salt atoms, because of their taste, are sharp and pointed ● Air atoms are light and whirling, pervading all other materials 20th July '11 Introduction to Particle Physics 5 Corpuscular Theory of Light Light consist out of particles (Newton et al.) ↕ Light is a wave (Huygens et al.) ● Mainly because of Newtons prestige, the corpuscle theory was widely accepted (more than 100 years) Sir Isaac Newton ● Failing to describe interference, diffraction, and *1643, †1727 polarization (e.g.
    [Show full text]
  • Exploring the Spectrum of QCD Using a Space-Time Lattice
    ExploringExploring thethe spectrumspectrum ofof QCDQCD usingusing aa spacespace--timetime latticelattice Colin Morningstar (Carnegie Mellon University) New Theoretical Tools for Nucleon Resonance Analysis Argonne National Laboratory August 31, 2005 August 31, 2005 Exploring spectrum (C. Morningstar) 1 OutlineOutline z spectroscopy is a powerful tool for distilling key degrees of freedom z calculating spectrum of QCD Æ introduction of space-time lattice spectrum determination requires extraction of excited-state energies discuss how to extract excited-state energies from Monte Carlo estimates of correlation functions in Euclidean lattice field theory z applications: Yang-Mills glueballs heavy-quark hybrid mesons baryon and meson spectrum (work in progress) August 31, 2005 Exploring spectrum (C. Morningstar) 2 MonteMonte CarloCarlo methodmethod withwith spacespace--timetime latticelattice z introduction of space-time lattice allows Monte Carlo evaluation of path integrals needed to extract spectrum from QCD Lagrangian LQCD Lagrangian of hadron spectrum, QCD structure, transitions z tool to search for better ways of calculating in gauge theories what dominates the path integrals? (instantons, center vortices,…) construction of effective field theory of glue? (strings,…) August 31, 2005 Exploring spectrum (C. Morningstar) 3 EnergiesEnergies fromfrom correlationcorrelation functionsfunctions z stationary state energies can be extracted from asymptotic decay rate of temporal correlations of the fields (in the imaginary time formalism) Ht −Ht z evolution in Heisenberg picture φ ( t ) = e φ ( 0 ) e ( H = Hamiltonian) z spectral representation of a simple correlation function assume transfer matrix, ignore temporal boundary conditions focus only on one time ordering insert complete set of 0 φφ(te) (0) 0 = ∑ 0 Htφ(0) e−Ht nnφ(0) 0 energy eigenstates n (discrete and continuous) 2 −−()EEnn00t −−()EEt ==∑∑neφ(0) 0 Ane nn z extract A 1 and E 1 − E 0 as t → ∞ (assuming 0 φ ( 0 ) 0 = 0 and 1 φ ( 0 ) 0 ≠ 0) August 31, 2005 Exploring spectrum (C.
    [Show full text]
  • Color Breaking in the Quantum Leaped Stop Decay
    Color breaking in the quantum leaped stop decay Imre Czövek [email protected] Abstract. The superfield propagator contains a measurable quantum leap, which comes from the definition of SUSY. In the sfermion -> Goldstino + fermion vertex change: 1. the spin of sparticle with discrete 1/2, 2. the Grassman superspace with the Goldstino shift operator. 3. the spacetime as the result of extra dimensional leap. The leap nature of SUSY transformations appears in the squark decay, it is the analog definition of SUSY. The quantum leaped outgoing propagators are determined and break locally the energy and the charge. Like to the teleportation the entangled pairs are here the b quark and the Goldstino. The dominant stop production is from gluons. The stop-antistop pair decay to quantum leaped b (c or t) quark, and the decay break the color. I get for the (color breaking) quantum leap: 10^-18 m. 10^-11 m color breaking would be needed for a color breaking chain reaction. The open question is: Are the colliders producing supersymmetry charge? Because some charges in QGP can make long color breaking and a chain reaction. A long color broken QGP state in the re-Big Bang theory could explain the near infinite energy and the near infinite mass of the universe: - at first was random color QGP in the flat space-time, - at twice the color restoration in the curved space-time, which eats the Goldstinos, - and finally the baryon genesis. The re Big Bang make a supernova like collapse and a flat explosion of Universe. This explanation of SUSY hides the Goldstone fermion in the extra dimensions, the Goldstino propagate only in superspace and it is a not observable dark matter.
    [Show full text]
  • Quantum Field Theory*
    Quantum Field Theory y Frank Wilczek Institute for Advanced Study, School of Natural Science, Olden Lane, Princeton, NJ 08540 I discuss the general principles underlying quantum eld theory, and attempt to identify its most profound consequences. The deep est of these consequences result from the in nite number of degrees of freedom invoked to implement lo cality.Imention a few of its most striking successes, b oth achieved and prosp ective. Possible limitation s of quantum eld theory are viewed in the light of its history. I. SURVEY Quantum eld theory is the framework in which the regnant theories of the electroweak and strong interactions, which together form the Standard Mo del, are formulated. Quantum electro dynamics (QED), b esides providing a com- plete foundation for atomic physics and chemistry, has supp orted calculations of physical quantities with unparalleled precision. The exp erimentally measured value of the magnetic dip ole moment of the muon, 11 (g 2) = 233 184 600 (1680) 10 ; (1) exp: for example, should b e compared with the theoretical prediction 11 (g 2) = 233 183 478 (308) 10 : (2) theor: In quantum chromo dynamics (QCD) we cannot, for the forseeable future, aspire to to comparable accuracy.Yet QCD provides di erent, and at least equally impressive, evidence for the validity of the basic principles of quantum eld theory. Indeed, b ecause in QCD the interactions are stronger, QCD manifests a wider variety of phenomena characteristic of quantum eld theory. These include esp ecially running of the e ective coupling with distance or energy scale and the phenomenon of con nement.
    [Show full text]
  • Higgs and Particle Production in Nucleus-Nucleus Collisions
    Higgs and Particle Production in Nucleus-Nucleus Collisions Zhe Liu Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences Columbia University 2016 c 2015 Zhe Liu All Rights Reserved Abstract Higgs and Particle Production in Nucleus-Nucleus Collisions Zhe Liu We apply a diagrammatic approach to study Higgs boson, a color-neutral heavy particle, pro- duction in nucleus-nucleus collisions in the saturation framework without quantum evolution. We assume the strong coupling constant much smaller than one. Due to the heavy mass and colorless nature of Higgs particle, final state interactions are absent in our calculation. In order to treat the two nuclei dynamically symmetric, we use the Coulomb gauge which gives the appropriate light cone gauge for each nucleus. To further eliminate initial state interactions we choose specific prescriptions in the light cone propagators. We start the calculation from only two nucleons in each nucleus and then demonstrate how to generalize the calculation to higher orders diagrammatically. We simplify the diagrams by the Slavnov-Taylor-Ward identities. The resulting cross section is factorized into a product of two Weizsäcker-Williams gluon distributions of the two nuclei when the transverse momentum of the produced scalar particle is around the saturation momentum. To our knowledge this is the first process where an exact analytic formula has been formed for a physical process, involving momenta on the order of the saturation momentum, in nucleus-nucleus collisions in the quasi-classical approximation. Since we have performed the calculation in an unconventional gauge choice, we further confirm our results in Feynman gauge where the Weizsäcker-Williams gluon distribution is interpreted as a transverse momentum broadening of a hard gluons traversing a nuclear medium.
    [Show full text]
  • Unification of Nature's Fundamental Forces
    Unification of Nature’s Geoffrey B. West Fredrick M. Cooper Fundamental Forces Emil Mottola a continuing search Michael P. Mattis it was explicitly recognized at the time that basic research had an im- portant and seminal role to play even in the highly programmatic en- vironment of the Manhattan Project. Not surprisingly this mode of opera- tion evolved into the remarkable and unique admixture of pure, applied, programmatic, and technological re- search that is the hallmark of the present Laboratory structure. No- where in the world today can one find under one roof such diversity of talent dealing with such a broad range of scientific and technological challenges—from questions con- cerning the evolution of the universe and the nature of elementary parti- cles to the structure of new materi- als, the design and control of weapons, the mysteries of the gene, and the nature of AIDS! Many of the original scientists would have, in today’s parlance, identified themselves as nuclear or particle physicists. They explored the most basic laws of physics and continued the search for and under- standing of the “fundamental build- ing blocks of nature’’ and the princi- t is a well-known, and much- grappled with deep questions con- ples that govern their interactions. overworked, adage that the group cerning the consequences of quan- It is therefore fitting that this area of Iof scientists brought to Los tum mechanics, the structure of the science has remained a highly visi- Alamos to work on the Manhattan atom and its nucleus, and the devel- ble and active component of the Project constituted the greatest as- opment of quantum electrodynamics basic research activity at Los Alam- semblage of scientific talent ever (QED, the relativistic quantum field os.
    [Show full text]
  • Baryon Number Fluctuation and the Quark-Gluon Plasma
    Baryon Number Fluctuation and the Quark-Gluon Plasma Z. W. Lin and C. M. Ko Because of the fractional baryon number Using the generating function at of quarks, baryon and antibaryon number equilibrium, fluctuations in the quark-gluon plasma is less than those in the hadronic matter, making them plausible signatures for the quark-gluon plasma expected to be formed in relativistic heavy ion with g(l) = ∑ Pn = 1 due to normalization of collisions. To illustrate this possibility, we have the multiplicity probability distribution, it is introduced a kinetic model that takes into straightforward to obtain all moments of the account both production and annihilation of equilibrium multiplicity distribution. In terms of quark-antiquark or baryon-antibaryon pairs [1]. the fundamental unit of baryon number bo in the In the case of only baryon-antibaryon matter, the mean baryon number per event is production from and annihilation to two mesons, given by i.e., m1m2 ↔ BB , we have the following master equation for the multiplicity distribution of BB pairs: while the squared baryon number fluctuation per baryon at equilibrium is given by In obtaining the last expressions in Eqs. (5) and In the above, Pn(ϑ) denotes the probability of ϑ 〈σ 〉 (6), we have kept only the leading term in E finding n pairs of BB at time ; G ≡ G v 〈σ 〉 corresponding to the grand canonical limit, and L ≡ L v are the momentum-averaged cross sections for baryon production and E 1, as baryons and antibaryons are abundantly produced in heavy ion collisions at annihilation, respectively; Nk represents the total number of particle species k; and V is the proper RHIC.
    [Show full text]
  • Fully Strange Tetraquark Sss¯S¯ Spectrum and Possible Experimental Evidence
    PHYSICAL REVIEW D 103, 016016 (2021) Fully strange tetraquark sss¯s¯ spectrum and possible experimental evidence † Feng-Xiao Liu ,1,2 Ming-Sheng Liu,1,2 Xian-Hui Zhong,1,2,* and Qiang Zhao3,4,2, 1Department of Physics, Hunan Normal University, and Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Changsha 410081, China 2Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Hunan Normal University, Changsha 410081, China 3Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China 4University of Chinese Academy of Sciences, Beijing 100049, China (Received 21 August 2020; accepted 5 January 2021; published 26 January 2021) In this work, we construct 36 tetraquark configurations for the 1S-, 1P-, and 2S-wave states, and make a prediction of the mass spectrum for the tetraquark sss¯s¯ system in the framework of a nonrelativistic potential quark model without the diquark-antidiquark approximation. The model parameters are well determined by our previous study of the strangeonium spectrum. We find that the resonances f0ð2200Þ and 2340 2218 2378 f2ð Þ may favor the assignments of ground states Tðsss¯s¯Þ0þþ ð Þ and Tðsss¯s¯Þ2þþ ð Þ, respectively, and the newly observed Xð2500Þ at BESIII may be a candidate of the lowest mass 1P-wave 0−þ state − 2481 0þþ 2440 Tðsss¯s¯Þ0 þ ð Þ. Signals for the other ground state Tðsss¯s¯Þ0þþ ð Þ may also have been observed in PC −− the ϕϕ invariant mass spectrum in J=ψ → γϕϕ at BESIII. The masses of the J ¼ 1 Tsss¯s¯ states are predicted to be in the range of ∼2.44–2.99 GeV, which indicates that the ϕð2170Þ resonance may not be a good candidate of the Tsss¯s¯ state.
    [Show full text]
  • An Interpreter's Glossary at a Conference on Recent Developments in the ATLAS Project at CERN
    Faculteit Letteren & Wijsbegeerte Jef Galle An interpreter’s glossary at a conference on recent developments in the ATLAS project at CERN Masterproef voorgedragen tot het behalen van de graad van Master in het Tolken 2015 Promotor Prof. Dr. Joost Buysschaert Vakgroep Vertalen Tolken Communicatie 2 ACKNOWLEDGEMENTS First of all, I would like to express my sincere gratitude towards prof. dr. Joost Buysschaert, my supervisor, for his guidance and patience throughout this entire project. Furthermore, I wanted to thank my parents for their patience and support. I would like to express my utmost appreciation towards Sander Myngheer, whose time and insights in the field of physics were indispensable for this dissertation. Last but not least, I wish to convey my gratitude towards prof. dr. Ryckbosch for his time and professional advice concerning the quality of the suggested translations into Dutch. ABSTRACT The goal of this Master’s thesis is to provide a model glossary for conference interpreters on assignments in the domain of particle physics. It was based on criteria related to quality, role, cognition and conference interpreters’ preparatory methodology. This dissertation focuses on terminology used in scientific discourse on the ATLAS experiment at the European Organisation for Nuclear Research. Using automated terminology extraction software (MultiTerm Extract) 15 terms were selected and analysed in-depth in this dissertation to draft a glossary that meets the standards of modern day conference interpreting. The terms were extracted from a corpus which consists of the 50 most recent research papers that were publicly available on the official CERN document server. The glossary contains information I considered to be of vital importance based on relevant literature: collocations in both languages, a Dutch translation, synonyms whenever they were available, English pronunciation and a definition in Dutch for the concepts that are dealt with.
    [Show full text]
  • On Particle Physics
    On Particle Physics Searching for the Fundamental US ATLAS The continuing search for the basic building blocks of matter is the US ATLAS subject of Particle Physics (also called High Energy Physics). The idea of fundamental building blocks has evolved from the concept of four elements (earth, air, fire and water) of the Ancient Greeks to the nineteenth century picture of atoms as tiny “billiard balls.” The key word here is FUNDAMENTAL — objects which are simple and have no structure — they are not made of anything smaller! Our current understanding of these fundamental constituents began to fall into place around 100 years ago, when experimenters first discovered that the atom was not fundamental at all, but was itself made of smaller building blocks. Using particle probes as “microscopes,” scientists deter- mined that an atom has a dense center, or NUCLEUS, of positive charge surrounded by a dilute “cloud” of light, negatively- charged electrons. In between the nucleus and electrons, most of the atom is empty space! As the particle “microscopes” became more and more powerful, scientists found that the nucleus was composed of two types of yet smaller constituents called protons and neutrons, and that even pro- tons and neutrons are made up of smaller particles called quarks. The quarks inside the nucleus come in two varieties, called “up” or u-quark and “down” or d-quark. As far as we know, quarks and electrons really are fundamental (although experimenters continue to look for evidence to the con- trary). We know that these fundamental building blocks are small, but just how small are they? Using probes that can “see” down to very small distances inside the atom, physicists know that quarks and electrons are smaller than 10-18 (that’s 0.000 000 000 000 000 001! ) meters across.
    [Show full text]