Topics in Modern Physics Teacher Resource Materials
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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. -
The Particle World
The Particle World ² What is our Universe made of? This talk: ² Where does it come from? ² particles as we understand them now ² Why does it behave the way it does? (the Standard Model) Particle physics tries to answer these ² prepare you for the exercise questions. Later: future of particle physics. JMF Southampton Masterclass 22–23 Mar 2004 1/26 Beginning of the 20th century: atoms have a nucleus and a surrounding cloud of electrons. The electrons are responsible for almost all behaviour of matter: ² emission of light ² electricity and magnetism ² electronics ² chemistry ² mechanical properties . technology. JMF Southampton Masterclass 22–23 Mar 2004 2/26 Nucleus at the centre of the atom: tiny Subsequently, particle physicists have yet contains almost all the mass of the discovered four more types of quark, two atom. Yet, it’s composite, made up of more pairs of heavier copies of the up protons and neutrons (or nucleons). and down: Open up a nucleon . it contains ² c or charm quark, charge +2=3 quarks. ² s or strange quark, charge ¡1=3 Normal matter can be understood with ² t or top quark, charge +2=3 just two types of quark. ² b or bottom quark, charge ¡1=3 ² + u or up quark, charge 2=3 Existed only in the early stages of the ² ¡ d or down quark, charge 1=3 universe and nowadays created in high energy physics experiments. JMF Southampton Masterclass 22–23 Mar 2004 3/26 But this is not all. The electron has a friend the electron-neutrino, ºe. Needed to ensure energy and momentum are conserved in ¯-decay: ¡ n ! p + e + º¯e Neutrino: no electric charge, (almost) no mass, hardly interacts at all. -
B2.IV Nuclear and Particle Physics
B2.IV Nuclear and Particle Physics A.J. Barr February 13, 2014 ii Contents 1 Introduction 1 2 Nuclear 3 2.1 Structure of matter and energy scales . 3 2.2 Binding Energy . 4 2.2.1 Semi-empirical mass formula . 4 2.3 Decays and reactions . 8 2.3.1 Alpha Decays . 10 2.3.2 Beta decays . 13 2.4 Nuclear Scattering . 18 2.4.1 Cross sections . 18 2.4.2 Resonances and the Breit-Wigner formula . 19 2.4.3 Nuclear scattering and form factors . 22 2.5 Key points . 24 Appendices 25 2.A Natural units . 25 2.B Tools . 26 2.B.1 Decays and the Fermi Golden Rule . 26 2.B.2 Density of states . 26 2.B.3 Fermi G.R. example . 27 2.B.4 Lifetimes and decays . 27 2.B.5 The flux factor . 28 2.B.6 Luminosity . 28 2.C Shell Model § ............................. 29 2.D Gamma decays § ............................ 29 3 Hadrons 33 3.1 Introduction . 33 3.1.1 Pions . 33 3.1.2 Baryon number conservation . 34 3.1.3 Delta baryons . 35 3.2 Linear Accelerators . 36 iii CONTENTS CONTENTS 3.3 Symmetries . 36 3.3.1 Baryons . 37 3.3.2 Mesons . 37 3.3.3 Quark flow diagrams . 38 3.3.4 Strangeness . 39 3.3.5 Pseudoscalar octet . 40 3.3.6 Baryon octet . 40 3.4 Colour . 41 3.5 Heavier quarks . 43 3.6 Charmonium . 45 3.7 Hadron decays . 47 Appendices 48 3.A Isospin § ................................ 49 3.B Discovery of the Omega § ...................... -
Muon Decay 1
Muon Decay 1 LIFETIME OF THE MUON Introduction Muons are unstable particles; otherwise, they are rather like electrons but with much higher masses, approximately 105 MeV. Radioactive nuclear decays do not release enough energy to produce them; however, they are readily available in the laboratory as the dominant component of the cosmic ray flux at the earth’s surface. There are two types of muons, with opposite charge, and they decay into electrons or positrons and two neutrinos according to the rules + + µ → e νe ν¯µ − − µ → e ν¯e νµ . The muon decay is a radioactiveprocess which follows the usual exponential law for the probability of survival for a given time t. Be sure that you understand the basis for this law. The goal of the experiment is to measure the muon lifetime which is roughly 2 µs. With care you can make the measurement with an accuracy of a few percent or better. In order to achieve this goal in a conceptually simple way, we look only at those muons that happen to come to rest inside our detector. That is, we first capture a muon and then measure the elapsed time until it decays. Muons are rather penetrating particles, they can easily go through meters of concrete. Nevertheless, a small fraction of the muons will be slowed down and stopped in the detector. As shown in Figure 1, the apparatus consists of two types of detectors. There is a tank filled with liquid scintillator (a big metal box) viewed by two photomultiplier tubes (Left and Right) and two plastic scintillation counters (flat panels wrapped in black tape), each viewed by a photomul- tiplier tube (Top and Bottom). -
The Structure of Quarks and Leptons
The Structure of Quarks and Leptons They have been , considered the elementary particles ofmatter, but instead they may consist of still smaller entities confjned within a volume less than a thousandth the size of a proton by Haim Harari n the past 100 years the search for the the quark model that brought relief. In imagination: they suggest a way of I ultimate constituents of matter has the initial formulation of the model all building a complex world out of a few penetrated four layers of structure. hadrons could be explained as combina simple parts. All matter has been shown to consist of tions of just three kinds of quarks. atoms. The atom itself has been found Now it is the quarks and leptons Any theory of the elementary particles to have a dense nucleus surrounded by a themselves whose proliferation is begin fl. of matter must also take into ac cloud of electrons. The nucleus in turn ning to stir interest in the possibility of a count the forces that act between them has been broken down into its compo simpler-scheme. Whereas the original and the laws of nature that govern the nent protons and neutrons. More recent model had three quarks, there are now forces. Little would be gained in simpli ly it has become apparent that the pro thought to be at least 18, as well as six fying the spectrum of particles if the ton and the neutron are also composite leptons and a dozen other particles that number of forces and laws were thereby particles; they are made up of the small act as carriers of forces. -
First Determination of the Electric Charge of the Top Quark
First Determination of the Electric Charge of the Top Quark PER HANSSON arXiv:hep-ex/0702004v1 1 Feb 2007 Licentiate Thesis Stockholm, Sweden 2006 Licentiate Thesis First Determination of the Electric Charge of the Top Quark Per Hansson Particle and Astroparticle Physics, Department of Physics Royal Institute of Technology, SE-106 91 Stockholm, Sweden Stockholm, Sweden 2006 Cover illustration: View of a top quark pair event with an electron and four jets in the final state. Image by DØ Collaboration. Akademisk avhandling som med tillst˚and av Kungliga Tekniska H¨ogskolan i Stock- holm framl¨agges till offentlig granskning f¨or avl¨aggande av filosofie licentiatexamen fredagen den 24 november 2006 14.00 i sal FB54, AlbaNova Universitets Center, KTH Partikel- och Astropartikelfysik, Roslagstullsbacken 21, Stockholm. Avhandlingen f¨orsvaras p˚aengelska. ISBN 91-7178-493-4 TRITA-FYS 2006:69 ISSN 0280-316X ISRN KTH/FYS/--06:69--SE c Per Hansson, Oct 2006 Printed by Universitetsservice US AB 2006 Abstract In this thesis, the first determination of the electric charge of the top quark is presented using 370 pb−1 of data recorded by the DØ detector at the Fermilab Tevatron accelerator. tt¯ events are selected with one isolated electron or muon and at least four jets out of which two are b-tagged by reconstruction of a secondary decay vertex (SVT). The method is based on the discrimination between b- and ¯b-quark jets using a jet charge algorithm applied to SVT-tagged jets. A method to calibrate the jet charge algorithm with data is developed. A constrained kinematic fit is performed to associate the W bosons to the correct b-quark jets in the event and extract the top quark electric charge. -
ANTIPROTON and NEUTRINO PRODUCTION ACCELERATOR TIMELINE ISSUES Dave Mcginnis August 28, 2005
ANTIPROTON AND NEUTRINO PRODUCTION ACCELERATOR TIMELINE ISSUES Dave McGinnis August 28, 2005 INTRODUCTION Most of the accelerator operating period is devoted to making antiprotons for the Collider program and accelerating protons for the NUMI program. While stacking antiprotons, the same Main Injector 120 GeV acceleration cycle is used to accelerate protons bound for the antiproton production target and protons bound for the NUMI neutrino production target. This is designated as Mixed-Mode operations. The minimum cycle time is limited by the time it takes to fill the Main Injector with two Booster batches for antiproton production and five Booster batches for neutrino production (7 x 0.067 seconds) and the Main Injector ramp rate (~ 1.5 seconds). As the antiproton stack size grows, the Accumulator stochastic cooling systems slow down which requires the cycle time to be lengthened. The lengthening of the cycle time unfortunately reduces the NUMI neutrino flux. This paper will use a simple antiproton stacking model to explore some of the tradeoffs between antiproton stacking and neutrino production. ACCUMULATOR STACKTAIL SYSTEM After the target, antiprotons are injected into the Debuncher ring where they undergo a bunch rotation and are stochastically pre-cooled for injection into the Accumulator. A fresh beam pulse injected into the Accumulator from the Debuncher is merged with previous beam pulses with the Accumulator StackTail system. This system cools and decelerates the antiprotons until the antiprotons are captured by the core cooling systems as shown in Figure 1. The antiproton flux through the Stacktail system is described by the Fokker –Plank equation ∂ψ ∂φ = − (1) ∂t ∂E where φ the flux of particles passing through the energy E and ψ is the particle density of the beam at energy E. -
Muon Neutrino Mass Without Oscillations
The Distant Possibility of Using a High-Luminosity Muon Source to Measure the Mass of the Neutrino Independent of Flavor Oscillations By John Michael Williams [email protected] Markanix Co. P. O. Box 2697 Redwood City, CA 94064 2001 February 19 (v. 1.02) Abstract: Short-baseline calculations reveal that if the neutrino were massive, it would show a beautifully structured spectrum in the energy difference between storage ring and detector; however, this spectrum seems beyond current experimental reach. An interval-timing paradigm would not seem feasible in a short-baseline experiment; however, interval timing on an Earth-Moon long baseline experiment might be able to improve current upper limits on the neutrino mass. Introduction After the Kamiokande and IMB proton-decay detectors unexpectedly recorded neutrinos (probably electron antineutrinos) arriving from the 1987A supernova, a plethora of papers issued on how to use this happy event to estimate the mass of the neutrino. Many of the estimates based on these data put an upper limit on the mass of the electron neutrino of perhaps 10 eV c2 [1]. When Super-Kamiokande and other instruments confirmed the apparent deficit in electron neutrinos from the Sun, and when a deficit in atmospheric muon- neutrinos likewise was observed, this prompted the extension of the kaon-oscillation theory to neutrinos, culminating in a flavor-oscillation theory based by analogy on the CKM quark mixing matrix. The oscillation theory was sensitive enough to provide evidence of a neutrino mass, even given the low statistics available at the largest instruments. J. M. Williams Neutrino Mass Without Oscillations (2001-02-19) 2 However, there is reason to doubt that the CKM analysis validly can be applied physically over the long, nonvirtual propagation distances of neutrinos [2]. -
Lecture 2 - Energy and Momentum
Lecture 2 - Energy and Momentum E. Daw February 16, 2012 1 Energy In discussing energy in a relativistic course, we start by consid- ering the behaviour of energy in the three regimes we worked with last time. In the first regime, the particle velocity v is much less than c, or more precisely β < 0:3. In this regime, the rest energy ER that the particle has by virtue of its non{zero rest mass is much greater than the kinetic energy T which it has by virtue of its kinetic energy. The rest energy is given by Einstein's famous equation, 2 ER = m0c (1) So, here is an example. An electron has a rest mass of 0:511 MeV=c2. What is it's rest energy?. The important thing here is to realise that there is no need to insert a factor of (3×108)2 to convert from rest mass in MeV=c2 to rest energy in MeV. The units are such that 0.511 is already an energy in MeV, and to get to a mass you would need to divide by c2, so the rest mass is (0:511 MeV)=c2, and all that is left to do is remove the brackets. If you divide by 9 × 1016 the answer is indeed a mass, but the units are eV m−2s2, and I'm sure you will appreciate why these units are horrible. Enough said about that. Now, what about kinetic energy? In the non{relativistic regime β < 0:3, the kinetic energy is significantly smaller than the rest 1 energy. -
Muons: Particles of the Moment
FEATURES Measurements of the anomalous magnetic moment of the muon provide strong hints that the Standard Model of particle physics might be incomplete Muons: particles of the moment David W Hertzog WHEN asked what the most important strange, bottom and top; and six leptons, issue in particle physics is today, my ABORATORY namely the electron, muon and tau- colleagues offer three burning ques- L lepton plus their associated neutrinos. ATIONAL tions: What is the origin of mass? Why N A different set of particles is respon- is the universe made of matter and not sible for the interactions between these equal parts of matter and antimatter? ROOKHAVEN matter particles in the model. The elec- And is there any physics beyond the B tromagnetic interaction that binds elec- Standard Model? trons to nuclei results from the exchange The first question is being addressed of photons, whereas the strong force by a feverish quest to find the Higgs that binds quarks together inside neut- boson, which is believed to be respon- rons, protons and other hadrons is car- sible for the mass of fundamental par- ried by particles called gluons. The ticles. The Tevatron at Fermilab, which third force in the Standard Model – the is currently running, or the Large Had- weak nuclear interaction, which is re- ron Collider at CERN, which is due sponsible for radioactive decay – is car- to start experiments in 2007, should OWMAN ried by the W and Z bosons. B IPP eventually provide the answer to this R Physicists love the Standard Model, question by detecting the Higgs and but they do not like it. -
Antiproton–Proton Scattering Experiments with Polarization ( Collaboration) PAX Abstract
Technical Proposal for Antiproton–Proton Scattering Experiments with Polarization ( Collaboration) PAX arXiv:hep-ex/0505054v1 17 May 2005 J¨ulich, May 2005 2 Technical Proposal for PAX Frontmatter 3 Technical Proposal for Antiproton–Proton Scattering Experiments with Polarization ( Collaboration) PAX Abstract Polarized antiprotons, produced by spin filtering with an internal polarized gas target, provide access to a wealth of single– and double–spin observables, thereby opening a new window to physics uniquely accessible at the HESR. This includes a first measurement of the transversity distribution of the valence quarks in the proton, a test of the predicted opposite sign of the Sivers–function, related to the quark dis- tribution inside a transversely polarized nucleon, in Drell–Yan (DY) as compared to semi–inclusive DIS, and a first measurement of the moduli and the relative phase of the time–like electric and magnetic form factors GE,M of the proton. In polarized and unpolarized pp¯ elastic scattering, open questions like the contribution from the odd charge–symmetry Landshoff–mechanism at large t and spin–effects in the extraction | | of the forward scattering amplitude at low t can be addressed. The proposed de- | | tector consists of a large–angle apparatus optimized for the detection of DY electron pairs and a forward dipole spectrometer with excellent particle identification. The design and performance of the new components, required for the polarized antiproton program, are outlined. A low–energy Antiproton Polarizer Ring (APR) yields an antiproton beam polarization of Pp¯ = 0.3 to 0.4 after about two beam life times, which is of the order of 5–10 h. -
The Standard Model and Beyond Maxim Perelstein, LEPP/Cornell U
The Standard Model and Beyond Maxim Perelstein, LEPP/Cornell U. NYSS APS/AAPT Conference, April 19, 2008 The basic question of particle physics: What is the world made of? What is the smallest indivisible building block of matter? Is there such a thing? In the 20th century, we made tremendous progress in observing smaller and smaller objects Today’s accelerators allow us to study matter on length scales as short as 10^(-18) m The world’s largest particle accelerator/collider: the Tevatron (located at Fermilab in suburban Chicago) 4 miles long, accelerates protons and antiprotons to 99.9999% of speed of light and collides them head-on, 2 The CDF million collisions/sec. detector The control room Particle Collider is a Giant Microscope! • Optics: diffraction limit, ∆min ≈ λ • Quantum mechanics: particles waves, λ ≈ h¯/p • Higher energies shorter distances: ∆ ∼ 10−13 cm M c2 ∼ 1 GeV • Nucleus: proton mass p • Colliders today: E ∼ 100 GeV ∆ ∼ 10−16 cm • Colliders in near future: E ∼ 1000 GeV ∼ 1 TeV ∆ ∼ 10−17 cm Particle Colliders Can Create New Particles! • All naturally occuring matter consists of particles of just a few types: protons, neutrons, electrons, photons, neutrinos • Most other known particles are highly unstable (lifetimes << 1 sec) do not occur naturally In Special Relativity, energy and momentum are conserved, • 2 but mass is not: energy-mass transfer is possible! E = mc • So, a collision of 2 protons moving relativistically can result in production of particles that are much heavier than the protons, “made out of” their kinetic