DOCSLIB.ORG

The Nuclear Physics of Muon Capture

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Nuclear Physics of Muon Capture Physics Reports 354 (2001) 243–409 The nuclear physics of muon capture D.F. Measday ∗ University of British Columbia, 6224 Agricultural Rd., Vancouver, BC, Canada V6T 1Z1 Received December 2000; editor: G:E: Brown Contents 4.8. Charged particles 330 4.9. Fission 335 1. Introduction 245 5. -ray studies 343 1.1. Prologue 245 5.1. Introduction 343 1.2. General introduction 245 5.2. Silicon-28 350 1.3. Previous reviews 247 5.3. Lithium, beryllium and boron 360 2. Fundamental concepts 248 5.4. Carbon, nitrogen and oxygen 363 2.1. Properties of the muon and neutrino 248 5.5. Fluorine and neon 372 2.2. Weak interactions 253 5.6. Sodium, magnesium, aluminium, 372 3. Muonic atom 264 phosphorus 3.1. Atomic capture 264 5.7. Sulphur, chlorine, and potassium 377 3.2. Muonic cascade 269 5.8. Calcium 379 3.3. Hyperÿne transition 275 5.9. Heavy elements 383 4. Muon capture in nuclei 281 6. Other topics 387 4.1. Hydrogen 282 6.1. Radiative muon capture 387 4.2. Deuterium and tritium 284 6.2. Summary of g determinations 391 4.3. Helium-3 290 P 6.3. The (; e±) reaction 393 4.4. Helium-4 294 7. Summary 395 4.5. Total capture rate 294 Acknowledgements 396 4.6. General features in nuclei 300 References 397 4.7. Neutron production 311 ∗ Tel.: +1-604-822-5098; fax: +1-604-822-5098. E-mail address: [email protected] (D.F. Measday). 0370-1573/01/$ - see front matter c 2001 Published by Elsevier Science B.V. PII: S 0370-1573(01)00012-6 244 D.F. Measday / Physics Reports 354 (2001) 243–409 Abstract We review the topic of muon capture in nuclei and show that signiÿcant nuclear physics is being learnt from recent experiments. The focus of many earlier experiments had been the particle physics and weak interactions aspects of the subject. Although these were useful conÿrmation of basic ideas, deÿning experiments mostly came from other areas. Thus, we focus on what can be learnt about nuclei especially 1+,1− and 2− magnetic transitions. Valuable comparisons can be made to other charge exchange reactions such as (−;), (−;0), (n; p), (d; 2 He) and (t; 3 He). However, all those experiments have resolutions of 300 keV to 1 MeV, or even worse, so -ray studies of muon capture provide resolutions 100–1000 times better, and thus deÿne the levels unambiguously. For even–even nuclei one can also compare to (e; e)at180◦,or(p; p) at forward angles, for which the resolution is reasonable, typically 50–100 keV, but isospin mixing complicates the comparison. With the recent substantial progress in Shell Model calculations, we anticipate signiÿcant developments in our understanding of nuclear structure in the next few years. c 2001 Published by Elsevier Science B.V. PACS: 23.40.Hc D.F. Measday / Physics Reports 354 (2001) 243–409 245 1. Introduction 1.1. Prologue Muon capture in nuclei has been a secluded garden slightly oC the main tourist routes of particle and nuclear physics. Few major discoveries have been made there, but it has often been a refuge where one could admire the beauty of nature and verify the ideas which were created elsewhere. The weak interaction has been a fertile zone of sub-atomic physics. Many major discoveries have been made therein and these are the foundation of many of our paradigms of particle physics such as “The Standard Model”. Muon physics has been a major part of that development, and muon capture in nuclei a useful adjunct. The ÿeld grew upon the research at the old synchrocyclotrons in the 1950s and 1960s and most of the basic concepts date from that era. There was a second coming at the meson factories in the 1980s and 1990s; improved equip- ment resolved many old problems although many remain. We postulate that these unresolved problems are due to the complexity of the nuclear environment and not due to an imperfect understanding of the weak interactions. Thus, we can now turn this around to use muon capture as an excellent test of our understanding of complex nuclei. With the recent improvement in calculational technology for the shell model in quite heavy nuclei, there is a very real hope that signiÿcant improvement in our knowledge will emerge. There are many existing reviews on muon capture but almost all written from the point of view of a theorist. This perspective is very valuable, but much information which is relevant to an experiment is omitted from such an approach. An obvious example is the subject of muonic X-rays which for a theorist is legitimately considered another topic. In an experiment however, muonic X-rays are both a curse and a blessing, but certainly cannot be ignored. Thus this review is written for those who may pursue such muon capture experiments in the future. We shall show that we now know what were the problems with previous experiments. To overcome these diIculties will take resources which may become available in new facilities such as the Joint Project for High Intensity Proton Accelerators at Tokai, Japan. 1.2. General introduction Ever since its discovery in 1937, the muon has been an enigma which has fascinated and frustrated physicists of several generations (not only the second). We shall take the point of view that the general properties of the muon have been established in particle experiments and that any new discoveries, as important as they will be, will not substantially aCect the problems addressed in muon capture. We shall also assume that lepton universality holds better than we need, so that the many lessons learned from ÿ decay can be transferred over to muon capture which thus can be considered as an extension of electron capture, though with many more states available. Muon capture centres on the simple semi-leptonic reaction − + p → n + ; (1.1) 246 D.F. Measday / Physics Reports 354 (2001) 243–409 which occurs via the charged current of the weak interactions. A feature which turns out to be critical is the extreme spin sensitivity of this reaction for p atoms in the 1s state. The singlet capture rate is about 660 s−1 whereas the triplet rate is only 12 s−1 or so. Many experiments performed at the old synchrocyclotrons showed that these capture rates for hydrogen are roughly correct, but the experiments are hard, and complicated by the fact that absorption actually takes place from a pp molecule. Recently, however, a remarkably precise experiment has been reported on the reaction − 3 3 + He → + H : (1.2) A rate of 1496 ± 4 s−1 was measured and this is in agreement with theoretical estimates for a statistical mixture of the hyperÿne states. We shall therefore assume that the particle physics aspects are well understood. When a muon reaches the 1s state of a muonic atom, it can decay or be captured on a bound proton. Except for very light nuclei this capture is far more likely than decay and it is the general features of this capture which will be the focus on this review. We shall show that the many characteristics which are poorly understood are reKections of the complexity of the nuclear environment. This manifests itself in two ways, either the renormalization of the coupling constants, or the complications of nuclear structure. Great strides are being made in understanding both aspects and we shall see that further developments are just around the corner. When muon capture occurs in any nucleus, the energy release of about 100 MeV is mainly donated to the neutrino, but the nucleus can and does absorb substantial energy, thus many reactions occur. Let us take 28Si as an example because we shall see that many experiments have focussed on this nuclide. First remember that in the 1s state of muonic silicon, the muon will decay 34% of the time and capture on the nucleus 66% of the time. Of those captures, about 36% will produce no neutrons, 49% will produce 1 neutron, 14% will produce 2 neutrons and 1% will produce 3 neutrons. Thus, symbolically: − 28 28 ∗ + Si → Al + : (1.3) Since an excitation of at least 21 MeV is required to produce 2 neutrons, we can see that the nucleus receives more than one might have expected. As a guide one should remember that, for muon capture from a p atom, the recoiling neutron takes only 5.2 MeV of kinetic energy, whilst the neutrino takes away 99.1 MeV. Most experiments have concentrated on the small fraction of reactions that leaves the ÿnal nucleus in a bound state. In this example 28Al is bound up to 7.7 MeV leaving over a hundred levels able to be excited. Fortunately, there are only a chosen few. It is known that 26% of the captures produce bound states of 28Al. (The diCerence between this number and the 36% above is that “no neutrons” includes a proton or an alpha being ejected from the nucleus.) The bound state transitions can be observed via their -ray emission, but only 16% of muon captures in 28Si have been identiÿed as going to 28Al bound states, i.e., about half of the expected number. This is typical of such comparisons for most nuclei, and we now realize that the other transitions are actually there, but just hidden in the overwhelming background. These other transitions often produce high energy -rays which are Doppler broadened, and the eIciency of the HPGe detector is much lower, so more experimental time is required. Modern experiments with larger, more eIcient detectors, could thus study the topic more D.F.
Load more

Recommended publications
  • The Particle Zoo
    219 8 The Particle Zoo 8.1 Introduction Around 1960 the situation in particle physics was very confusing. Elementary particlesa such as the photon, electron, muon and neutrino were known, but in addition many more particles were being discovered and almost any experiment added more to the list. The main property that these new particles had in common was that they were strongly interacting, meaning that they would interact strongly with protons and neutrons. In this they were different from photons, electrons, muons and neutrinos. A muon may actually traverse a nucleus without disturbing it, and a neutrino, being electrically neutral, may go through huge amounts of matter without any interaction. In other words, in some vague way these new particles seemed to belong to the same group of by Dr. Horst Wahl on 08/28/12. For personal use only. particles as the proton and neutron. In those days proton and neutron were mysterious as well, they seemed to be complicated compound states. At some point a classification scheme for all these particles including proton and neutron was introduced, and once that was done the situation clarified considerably. In that Facts And Mysteries In Elementary Particle Physics Downloaded from www.worldscientific.com era theoretical particle physics was dominated by Gell-Mann, who contributed enormously to that process of systematization and clarification. The result of this massive amount of experimental and theoretical work was the introduction of quarks, and the understanding that all those ‘new’ particles as well as the proton aWe call a particle elementary if we do not know of a further substructure.
    [Show full text]
  • Neutron Stars
    Chandra X-Ray Observatory X-Ray Astronomy Field Guide Neutron Stars Ordinary matter, or the stuff we and everything around us is made of, consists largely of empty space. Even a rock is mostly empty space. This is because matter is made of atoms. An atom is a cloud of electrons orbiting around a nucleus composed of protons and neutrons. The nucleus contains more than 99.9 percent of the mass of an atom, yet it has a diameter of only 1/100,000 that of the electron cloud. The electrons themselves take up little space, but the pattern of their orbit defines the size of the atom, which is therefore 99.9999999999999% Chandra Image of Vela Pulsar open space! (NASA/PSU/G.Pavlov et al. What we perceive as painfully solid when we bump against a rock is really a hurly-burly of electrons moving through empty space so fast that we can't see—or feel—the emptiness. What would matter look like if it weren't empty, if we could crush the electron cloud down to the size of the nucleus? Suppose we could generate a force strong enough to crush all the emptiness out of a rock roughly the size of a football stadium. The rock would be squeezed down to the size of a grain of sand and would still weigh 4 million tons! Such extreme forces occur in nature when the central part of a massive star collapses to form a neutron star. The atoms are crushed completely, and the electrons are jammed inside the protons to form a star composed almost entirely of neutrons.
    [Show full text]
  • 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]
  • Arxiv:2010.09509V2 [Hep-Ph] 2 Apr 2021 in Searches for CLFV Or LNV, Incoming Muons Are the Source of Both the Μ → E Signal and the RMC Back- Ground
    FERMILAB-PUB-20-525-T The high energy spectrum of internal positrons from radiative muon capture on nuclei Ryan Plestid1, 2, ∗ and Richard J. Hill1, 2, y 1Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506, USA 2Theoretical Physics Department, Fermilab, Batavia, IL 60510,USA (Dated: April 5, 2021) The Mu2e and COMET collaborations will search for nucleus-catalyzed muon conversion to positrons (µ− ! e+) as a signal of lepton number violation. A key background for this search is radiative muon capture where either: 1) a real photon converts to an e+e− pair “externally" in surrounding material; or 2) a virtual photon mediates the production of an e+e− pair “internally”. If the e+ has an energy approaching the signal region then it can serve as an irreducible background. In this work we describe how the near end-point internal positron spectrum can be related to the real photon spectrum from the same nucleus, which encodes all non-trivial nuclear physics. I. INTRODUCTION Specifically, on a nucleus (e.g. aluminum), the reaction µ− + [A; Z] ! e+ + [A; Z − 2] ; (1) Charged lepton flavor violation (CLFV) is a smok- ing gun signature of physics beyond the Standard Model becomes a viable target for observation (see also [7]). (SM) and is one of the most sought-after signals at the While neutrinoless double beta (0νββ) decay is often intensity frontier [1–4]. Important search channels in- touted as the most promising direction for the discovery volving the lightest two lepton generations are µ ! 3e, of LNV, there do exist extensions of the SM that predict µ ! eγ, and nucleus-catalyzed µ ! e [1–6].
    [Show full text]
  • The Lamb Shift Experiment in Muonic Hydrogen
    The Lamb Shift Experiment in Muonic Hydrogen Dissertation submitted to the Physics Faculty of the Ludwig{Maximilians{University Munich by Aldo Sady Antognini from Bellinzona, Switzerland Munich, November 2005 1st Referee : Prof. Dr. Theodor W. H¨ansch 2nd Referee : Prof. Dr. Dietrich Habs Date of the Oral Examination : December 21, 2005 Even if I don't think, I am. Itsuo Tsuda Je suis ou` je ne pense pas, je pense ou` je ne suis pas. Jacques Lacan A mia mamma e mio papa` con tanto amore Abstract The subject of this thesis is the muonic hydrogen (µ−p) Lamb shift experiment being performed at the Paul Scherrer Institute, Switzerland. Its goal is to measure the 2S 2P − energy difference in µp atoms by laser spectroscopy and to deduce the proton root{mean{ −3 square (rms) charge radius rp with 10 precision, an order of magnitude better than presently known. This would make it possible to test bound{state quantum electrody- namics (QED) in hydrogen at the relative accuracy level of 10−7, and will lead to an improvement in the determination of the Rydberg constant by more than a factor of seven. Moreover it will represent a benchmark for QCD theories. The experiment is based on the measurement of the energy difference between the F=1 F=2 2S1=2 and 2P3=2 levels in µp atoms to a precision of 30 ppm, using a pulsed laser tunable at wavelengths around 6 µm. Negative muons from a unique low{energy muon beam are −1 stopped at a rate of 70 s in 0.6 hPa of H2 gas.
    [Show full text]
  • MODERN DEVELOPMENT of MAGNETIC RESONANCE Abstracts 2020 KAZAN * RUSSIA
    MODERN DEVELOPMENT OF MAGNETIC RESONANCE abstracts 2020 KAZAN * RUSSIA OF MA NT GN E E M T P IC O L R E E V S E O N D A N N R C E E D O M K 20 AZAN 20 MODERN DEVELOPMENT OF MAGNETIC RESONANCE ABSTRACTS OF THE INTERNATIONAL CONFERENCE AND WORKSHOP “DIAMOND-BASED QUANTUM SYSTEMS FOR SENSING AND QUANTUM INFORMATION” Editors: ALEXEY A. KALACHEV KEV M. SALIKHOV KAZAN, SEPTEMBER 28–OCTOBER 2, 2020 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machines or similar means, and storage in data banks. © 2020 Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS, Kazan © 2020 Igor A. Aksenov, graphic design Printed in Russian Federation Published by Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of RAS, Kazan www.kfti.knc.ru v CHAIRMEN Alexey A. Kalachev Kev M. Salikhov PROGRAM COMMITTEE Kev Salikhov, chairman (Russia) Vadim Atsarkin (Russia) Elena Bagryanskaya (Russia) Pavel Baranov (Russia) Marina Bennati (Germany) Robert Bittl (Germany) Bernhard Blümich (Germany) Michael Bowman (USA) Gerd Buntkowsky (Germany) Sergei Demishev (Russia) Sabine Van Doorslaer (Belgium) Rushana Eremina (Russia) Jack Freed (USA) Philip Hemmer (USA) Konstantin Ivanov (Russia) Alexey Kalachev (Russia) Vladislav Kataev (Germany) Walter Kockenberger (Great Britain) Wolfgang Lubitz (Germany) Anders Lund (Sweden) Sergei Nikitin (Russia) Klaus Möbius (Germany) Hitoshi Ohta (Japan) Igor Ovchinnikov (Russia) Vladimir Skirda (Russia) Alexander Smirnov( Russia) Graham Smith (Great Britain) Mark Smith (Great Britain) Murat Tagirov (Russia) Takeji Takui (Japan) Valery Tarasov (Russia) Violeta Voronkova (Russia) vi LOCAL ORGANIZING COMMITTEE Kalachev A.A., chairman Kupriyanova O.O.
    [Show full text]
  • Identical Particles
    8.06 Spring 2016 Lecture Notes 4. Identical particles Aram Harrow Last updated: May 19, 2016 Contents 1 Fermions and Bosons 1 1.1 Introduction and two-particle systems .......................... 1 1.2 N particles ......................................... 3 1.3 Non-interacting particles .................................. 5 1.4 Non-zero temperature ................................... 7 1.5 Composite particles .................................... 7 1.6 Emergence of distinguishability .............................. 9 2 Degenerate Fermi gas 10 2.1 Electrons in a box ..................................... 10 2.2 White dwarves ....................................... 12 2.3 Electrons in a periodic potential ............................. 16 3 Charged particles in a magnetic field 21 3.1 The Pauli Hamiltonian ................................... 21 3.2 Landau levels ........................................ 23 3.3 The de Haas-van Alphen effect .............................. 24 3.4 Integer Quantum Hall Effect ............................... 27 3.5 Aharonov-Bohm Effect ................................... 33 1 Fermions and Bosons 1.1 Introduction and two-particle systems Previously we have discussed multiple-particle systems using the tensor-product formalism (cf. Section 1.2 of Chapter 3 of these notes). But this applies only to distinguishable particles. In reality, all known particles are indistinguishable. In the coming lectures, we will explore the mathematical and physical consequences of this. First, consider classical many-particle systems. If a single particle has state described by position and momentum (~r; p~), then the state of N distinguishable particles can be written as (~r1; p~1; ~r2; p~2;:::; ~rN ; p~N ). The notation (·; ·;:::; ·) denotes an ordered list, in which different posi­ tions have different meanings; e.g. in general (~r1; p~1; ~r2; p~2)6 = (~r2; p~2; ~r1; p~1). 1 To describe indistinguishable particles, we can use set notation.
    [Show full text]
  • Muonium-Antimuonium Conversion Abstract
    SciPost Phys. Proc. 5, 009 (2021) Muonium-antimuonium conversion Lorenz Willmann? and Klaus Jungmann Van Swinderen Institute, University of Groningen, 9747 AA, Groningen, The Netherlands ? [email protected] Review of Particle Physics at PSI doi:10.21468/SciPostPhysProc.5 Abstract The MACS experiment performed at PSI in the 1990s provided an yet unchallenged upper bound on the probability for a spontaneous conversion of the muonium atom, + + M =(µ e−), into its antiatom, antimuonium M =(µ−e ). It comprises the culmination of a series of measurements at various accelerator laboratories worldwide. The experimen- tal limits on the process have provided input and steering for the further development of a variety of theoretical models beyond the standard theory, in particular for mod- els which address lepton number violating processes and matter-antimatter oscillations. Several models beyond the standard theory could be strongly disfavored. There is inter- est in a new measurement and improved sensitivity could be reached by exploiting the time evolution of the conversion process, e.g., at intense pulsed muonium sources. Copyright L. Willmann and K. Jungmann. Received 16-02-2021 This work is licensed under the Creative Commons Accepted 28-04-2021 Check for Attribution 4.0 International License. Published 06-09-2021 updates Published by the SciPost Foundation. doi:10.21468/SciPostPhysProc.5.009 9.1 Introduction + The bound state of a positive muon (µ ) and an electron (e−) is an exotic atom which has been named muonium (M) by V.Telegdi. This exotic atom was first produced and observed by V.W. Hughes and collaborators in 1960 [1].
    [Show full text]
  • 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).
    [Show full text]
  • UC Irvine UC Irvine Previously Published Works
    UC Irvine UC Irvine Previously Published Works Title Astrophysics in 2006 Permalink https://escholarship.org/uc/item/5760h9v8 Journal Space Science Reviews, 132(1) ISSN 0038-6308 Authors Trimble, V Aschwanden, MJ Hansen, CJ Publication Date 2007-09-01 DOI 10.1007/s11214-007-9224-0 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Space Sci Rev (2007) 132: 1–182 DOI 10.1007/s11214-007-9224-0 Astrophysics in 2006 Virginia Trimble · Markus J. Aschwanden · Carl J. Hansen Received: 11 May 2007 / Accepted: 24 May 2007 / Published online: 23 October 2007 © Springer Science+Business Media B.V. 2007 Abstract The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the Universe) and others of which there are always many, like meteors and molecules, black holes and binaries. Keywords Cosmology: general · Galaxies: general · ISM: general · Stars: general · Sun: general · Planets and satellites: general · Astrobiology · Star clusters · Binary stars · Clusters of galaxies · Gamma-ray bursts · Milky Way · Earth · Active galaxies · Supernovae 1 Introduction Astrophysics in 2006 modifies a long tradition by moving to a new journal, which you hold in your (real or virtual) hands. The fifteen previous articles in the series are referenced oc- casionally as Ap91 to Ap05 below and appeared in volumes 104–118 of Publications of V.
    [Show full text]
  • 4 Muon Capture on the Deuteron 7 4.1 Theoretical Framework
    February 8, 2008 Muon Capture on the Deuteron The MuSun Experiment MuSun Collaboration model-independent connection via EFT http://www.npl.uiuc.edu/exp/musun V.A. Andreeva, R.M. Careye, V.A. Ganzhaa, A. Gardestigh, T. Gorringed, F.E. Grayg, D.W. Hertzogb, M. Hildebrandtc, P. Kammelb, B. Kiburgb, S. Knaackb, P.A. Kravtsova, A.G. Krivshicha, K. Kuboderah, B. Laussc, M. Levchenkoa, K.R. Lynche, E.M. Maeva, O.E. Maeva, F. Mulhauserb, F. Myhrerh, C. Petitjeanc, G.E. Petrova, R. Prieelsf , G.N. Schapkina, G.G. Semenchuka, M.A. Sorokaa, V. Tishchenkod, A.A. Vasilyeva, A.A. Vorobyova, M.E. Vznuzdaeva, P. Winterb aPetersburg Nuclear Physics Institute, Gatchina 188350, Russia bUniversity of Illinois at Urbana-Champaign, Urbana, IL 61801, USA cPaul Scherrer Institute, CH-5232 Villigen PSI, Switzerland dUniversity of Kentucky, Lexington, KY 40506, USA eBoston University, Boston, MA 02215, USA f Universit´eCatholique de Louvain, B-1348 Louvain-la-Neuve, Belgium gRegis University, Denver, CO 80221, USA hUniversity of South Carolina, Columbia, SC 29208, USA Co-spokespersons underlined. 1 Abstract: We propose to measure the rate Λd for muon capture on the deuteron to better than 1.5% precision. This process is the simplest weak interaction process on a nucleus that can both be calculated and measured to a high degree of precision. The measurement will provide a benchmark result, far more precise than any current experimental information on weak interaction processes in the two-nucleon system. Moreover, it can impact our understanding of fundamental reactions of astrophysical interest, like solar pp fusion and the ν + d reactions observed by the Sudbury Neutrino Observatory.
    [Show full text]
  • KAONIC and OTHER EXOTIC ATOMS 243 Atoms Got Underway in Earnest with the Invention and Application of Semiconductor Detectors
    Copyright 1975. All rights reserved KAONIC AND OTHER :.:5562 EXOTIC ATOMS Ryoichi Seki California State University, Northridge, California 91324 Clyde E. Wiegand Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 CONTENTS 1 INTRODUCTION................................................ 241 2 BASIC CHARACTERISTICS OF EXOTIC ATOMS. .. 245 3 EXPERIMENTAL FINDINGS. .. 248 3.1 X-Ray Intensities.. .. .. .. .. .. .. .. .. .. .. 248 248 3.1.1 Kaonic.atoms....................................... .. 3.1.2 Sigmonic atoms.. 250 . .. 3.1.3 Antiprotonic atoms. 250 . .. 3.2 Level Shifts and Widths. 250 . .. 256 3.3 Particle Properties Derivedfrom Exotic Atoms. 3.3.1 Mass.. 257 . .. 258 3.3.2 Magnetic moment.. 259 3.3.3 Polarizability....................................... .. 3.4 Atomic Phenomena Directly Related to Nuclear Properties. 260 '. .. 260 3.4.1 Nuclear quadrupole moment..... ............... .. 260 3.4.2 Dynamical quadrupole (E2) mixing. .. 261 3.5 Products from Nuclear Absorption of K-, �-, and p. 3. 5. 1 Particles observed in nuclear emulsions and bubble chambers.. 261 . 264 3.5.2 Nuclear y rays.. 4 THEORETICAL UNDERSTANDING. .. .. .. .. .. .. .. .. .. 265 . 4.1 Atomic Capture and Cascade.. 266 Annu. Rev. Nucl. Sci. 1975.25:241-281. Downloaded from www.annualreviews.org Atomic capture.. 266 Access provided by Pennsylvania State University on 02/13/15. For personal use only. 4.1.1 .. .. .. .. .. 267 4.1.2 Atomic cascade.. 268 4.2 Strong Interactions with Nuclei.. 269 4.2.1 K --nucleus optical potential.. - . 4.2.2 p- and � -nucleus optical potential. 276 27 4.3 Two- and One-Nucleon Absorption Products. .. .. .. .. .. .. .. 7 . .. 278 5 CONCLUDING REMARKS. 1 INTRODUCTION In this article we attempt to tell what is known about kaonie, sigmonic, and anti protonic atoms.
    [Show full text]