DOCSLIB.ORG

Structure and Dynamics of Highly Charged Ions and Pionic Atoms Martino Trassinelli

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Structure and Dynamics of Highly Charged Ions and Pionic Atoms Martino Trassinelli Structure and dynamics of highly charged ions and pionic atoms Martino Trassinelli To cite this version: Martino Trassinelli. Structure and dynamics of highly charged ions and pionic atoms. Atomic Physics [physics.atom-ph]. Univesité Pierre et Marie Curie, Sorbonne Universités, 2017. tel-01674426v2 HAL Id: tel-01674426 https://tel.archives-ouvertes.fr/tel-01674426v2 Submitted on 15 Jan 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Universit´ePierre et Marie Curie, Sorbonne Universit´es,Paris, France Habilitation `adiriger des recherches pr´esent´eepar Martino Trassinelli Charg´ede recherche CNRS (INP) Structure and dynamics of highly charged ions and pionic atoms Soutenue le 15 septembre 2017 devant le jury compos´ede : Jean-Michel RAIMOND Professeur (LKB, UPMC, Paris) Pr´esident Fr´edrich AUMAYR Professeur (IAP, Vienne) Rapporteur Jos´eR. CRESPO LOPEZ-URRUTIA´ Professeur (MPI, Heidelberg) Rapporteur Xavier FLECHARD´ Chercheur (CR1 avec HDR) (LPC, Caen) Rapporteur Eva LINDROTH Professeure (Univ. de Stockholm) Examinatrice Preface In this manuscript I present some of my research activities conducted during the past ten years starting from my hiring as researcher at the Centre National de la Recherche Scientifique (CNRS, National Center for Scientific Research) at the Institut des NanoSciences de Paris (INSP, Institute of NanoSciences of Paris). My research is carried out in the team Agr´egatset surfaces sous excitations intenses (ASUR, Clusters and Surfaces under Intense Excitation) and also with external collabora- tions: the atomic physics group of GSI Helmholtzzentrum f¨urSchwerionenforschung (GSI), and the Pion Hydrogen and Pion Mass collaboration. The work presented in this manuscript is the result of a teamwork without which the results discussed here would not have been possible. Except in this preface and when my contributions are expressly specified, all topics are presented as impersonal. Five chapters compose the manuscript. Chapter 1 is a general introduction. An overview of the different topics and the relationship between them in a general context are shortly presented. In the other chapters a selection of the most striking topics is detailed. Research activities on laser-cluster interactions [A11, C2, C8, C11, C13, C15], theoretical studies on ion{matter interaction [A10, C3] and plasma temperature measurements [A33] are not treated in this manuscript. Chapter 2 is dedicated to the data analysis methods. Two multipurpose analysis programs I developed in the last years are presented in this chapter. The first is based on the χ2 minimisation but with features that make it especially adapted for low-statistics spectra and where special functions can be included and employed for specific cases. The main feature of the second program is the possibility to compare different models describing the data and assign to them probabilities. This program is based on Bayesian statistics analysis methods that are introduced and presented as well in Ch. 2. Chapter 3 is dedicated to the measurement of the negatively charged pion mass using high-accuracy X-ray spectroscopy of pionic nitrogen and using a muonic oxygen transition as reference. In this chapter, I present, in particular, two particular aspects of the data analysis. The first one is the study of the line profile determined by the de-excitation cascade processes that occur after the creation of the bound system and the radiative emission of interest. The second one is the investigation of the presence or not of satellite lines due to the non-complete electron depletion. The presence of one or more electrons in addition to the pion, may cause, in fact, a shift of the radiative transition energies leading to a systematic effect. In chapter 4 I present the study of the collision of hydrogen-like argon with an atomic target at low velocity. Here, I focus on a particular aspect of the investigation: the atomic cascade processes and their comparison with theoretical predictions. The role of single- and multi-electron capture is revealed and the role of the presence of metastable states is evaluated. The effect of heavy and slow ion impact on giant magnetocaloric thin films is discussed in Chapter 5. This new subject, quite different from the others described in chapters 3 and 4, deserves specific i ii introductions on the ion{matter interaction and on the magnetocaloric effect. The description and characterisation of modifications induced by the ion irradiation in specific samples as manganese arsenide thin films are given. The results are discussed in a thermodynamical point of view that highlights the key role of the phase transition type (of first or second order) associated to the giant magnetocaloric effect. Finally, conclusions and perspectives of my future research projects are presented in the last part. Except for the general introduction, each chapter starts with an introductory section that ends with a specific part labeled in red where my personal contributions are presented with reference to my publication list. Integral texts of the most relevant publications associated to the different chapters are proposed in the appendices, together with auxiliary subjects. The manuscript is completed with my detailed curriculum vitae, the list of my oral contributions at conferences and workshops and the list of my publications. In the different chapters these publications are referred with a Latin letters and a progressive number: A for articles, B for book chapters, C for proceedings and D for patent. Other bibliographic references are indicated with simple numbers and can be found at the end of the document. Contents Preface i Contents iii 1 General introduction 1 1.1 General presentation . 1 1.2 Structure . 3 1.3 Dynamics . 5 1.4 Investigation methods . 9 1.5 Something completely different . 9 2 Statistics and data analysis methods and applications 11 2.1 Introduction . 11 2.2 A general fitting program: Minuit fit ........................... 12 2.3 Bayesian approach for data analysis . 16 2.4 The nested sampling for Bayesian evidence calculation . 21 2.5 A data analysis program based on Bayesian statistics: Nested fit . 24 3 The measurement of the mass of the negatively charged pion 27 3.1 Introduction . 27 3.2 Production of pionic and muonic atoms and detection of their radiative emission . 28 3.3 Spectral line shape . 32 3.4 Analysis of the data and discussions . 36 3.5 The new value of the charged pion mass . 43 4 Slow collisions between ions and atoms 47 4.1 Introduction . 47 4.2 Experimental set-up and methods . 49 4.3 Atomic cascade characteristics and modelling . 50 4.4 Discussions on the high-resolution spectra and comparison with theory predictions . 54 4.5 Final considerations . 59 5 Modification of properties of magnetocaloric thin films by ion irradiation 61 5.1 Introduction . 61 5.2 Ion { matter interaction . 62 5.3 Giant magnetocaloric effect and thin films . 66 iii iv Contents 5.4 Experimental methods . 75 5.5 Results and discussions of the ion irradiation effects . 77 5.6 Other samples and general discussion . 87 6 Perspectives 89 6.1 On the pion mass measurement . 89 6.2 Collisions of slow ions with atoms, clusters, surfaces and ions . 90 6.3 Giant magnetocaloric thin films irradiated with ions . 94 6.4 QED tests and dynamics collision with highly charged ions . 95 A Some recall on maximum likelihood and least-squares methods 97 A.1 The likelihood function . 97 A.2 Least-squares method and evaluation of parameter uncertainties . 98 B Classical over-the-barrier model 99 C Highly charged ion{surface interaction and other ion{matter processes 101 D Atomic cascade code for He-like ions 103 E Article about Bayesian data analysis methods 111 F Article about the pion mass measurement 125 G Article about ion{atom collisions 133 H Article about irradiation-induced modifications in magnetocaloric thin films 145 I Article about something completely different 151 Acronyms 165 Detailed Curriculum vitæ 167 Publications in international journals with referee comity 171 Book chapters 179 Proceedings with referee comity 181 Patents 185 Conferences and seminars 187 Bibliography 191 Chapter 1 General introduction 1.1 General presentation The activities presented in this manuscript are centred on pionic atoms (hydrogen-like atoms where electrons are substituted with a negatively charged pion) and highly charged ions (HCI) (atoms with high atomic number Z and only one or a few electrons). These atomic systems, apparently very different, are sharing many common features and their investigation is carried out thanks to similar characterisation techniques. If we consider the typical level energies En and electric fields of any E 1017 1016 1015 ) m 1014 c / V ( 1013 Max. Laser field 1012 1011 1010 0 25 50 75 100 Nuclear charge Z Figure 1.1 { Left: Average electric field relative to the 1s level as a function of the nuclear charge Z. As comparison, the value of the electric field of the most powerful available lasers is indicated in red. Right: Different QED and nuclear size effects as a function of the nuclear charge Z. 1 2 1. General introduction Highly charged ions and pionic atoms Structure Dynamics (A) (B) (C) (D) (E) (F) Interaction Nucleus and Collisional Decay Target Target forces particles(s) processes processes characterization modification Figure 1.2 { Scheme of the research topics presented in the manuscript. atomic system that are1 2 2 3 2 (Zα) 4 m c 3 En = mc + (Zα) and (Zα) ; (1.1) 2n2 O E ∼ e~ (where m is the reduced mass of the system, c the speed of light, α the fine constant, e the electron charge, ~ the reduced Planck constant and n the principal quantum number) we see that a larger mass of the orbiting particle or a high of the nuclear charge causes a considerable increase of En and .
Load more

Recommended publications
  • 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]
  • Exotic Atom Production with Upcs Joint EF07 and EF06 Discussion
    Exotic atom production with UPCs Joint EF07 and EF06 discussion: UPC physics with ion beams Tuesday Oct 13, 2020 C.A. Bertulani Texas A&M University-Commerce Gerhard Baur Mark Ellermann Fernando Navarra 1 Pair Production with Atomic Capture Bertulani, Baur, Phys. Rep. 163, 299 (1988) Brazilian J. Phys. 18, 559 (1988) '" = + = → (= + '0) + = + '" Ingredients: 1. Perturbation theory 2. Sommerfeld-Maue wavefunction (e+) 2%& ./( 6 " 012+34 Ψ" = ()* ' 1 + 8 3 9 : 2", 4 < ' + − 1 27" =? &" = v" 3. Bound state wavefunction (e-) ./( =>? @ 6 4 Ψ = 1 + =? 8 3 '0 BCD E F 0 % 2 A 2 Pair Production with Capture 33$ '( ) 1 !~ , ,./0 ln 4 − 2.051 10 *+ - − 1 Baur, Bertulani, NPA 505, 835 (1989) Luminosity: 8 = 8: exp −>? LHC, Pb+Pb à >~ 2 hours EF Mainly K-shell capture, with ~ 20% capture in higher atomic orbitals. Antihydrogen production: Baur, PLB 311, 343 (1993) Munger, Brodsky, Schmidt, PRD 49, 3228 (1994) 3 1996 Baur et al, PLB 368, 251 (1996) 4 First Production of AntiHydrogen Baur et al., PLB 368, 251 (1996) Fermilab 1998: Blanford et al, PRL 80, 3037 (1998) 11 events as predicted Bertulani, Baur, PRD 58, 034005 (1998) 5 Antihydrogen • $96 trillion dollars per gram of antihydrogen (most expensive material to produce) • CERN Antiproton Decelerator (AD) + atom trap • ALPHA experiment CERN: 1S ßà 2S transition à H same as H! within 200 ppt Moretti et al., Nature 419, 456 (2002) à no CPT violation à no “source” for baryon asymmetry • Hbar and anti-gravity: Amole et al., Nature Com. 4, 1785 (2013) à ± ($! gravitational)/($! inertial) mass < 75 à not conclusive • No antideuterium, antitritium, or antihelium atoms have ever been produced.
    [Show full text]
  • Arxiv:2104.06076V2 [Nucl-Ex] 19 Apr 2021 Related to This field
    Fundamental physics at the strangeness frontier at DAΦNE. Outline of a proposal for future measurements. C. Curceanu, C. Guaraldo, A. Scordo, D. Sirghi, Laboratori Nazionali di Frascati INFN, Via E. Fermi 54, Frascati, Italy K. Piscicchia Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Rome, Italy C. Amsler, J. Zmeskal Stefan Meyer Institute of the Austrian Academy of Sciences (SMI), Wien, Austria D. Bosnar Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia S. Eidelman Budker Institute of Nuclear Physics (SB RAS), Novosibirsk and Lebedev Physical Institute (RAS), Moscow, Russia H. Ohnishi, Y. Sada Research Center for Electron Photon Science, Tohoku University, Sendai, Japan The DAΦNE collider at INFN-LNF is a unique source of low-energy kaons, which was used by the DEAR, SIDDHARTA and AMADEUS collaborations for unique measurements of kaonic atoms and kaon-nuclei interactions. Presently, the SIDDHARTA-2 collaboration is underway to measure the kaonic deuterium exotic atom. With this document we outline a proposal for fundamental physics at the strangeness frontier for future measurements of kaonic atoms and kaon-nuclei interactions at DAΦNE, which is intended to stimulate discussions within the broad scientific community performing research directly or indirectly arXiv:2104.06076v2 [nucl-ex] 19 Apr 2021 related to this field. PACS numbers: 13.75.Jz, 36.10.-k, 36.10.Gv, 14.40.-n, 25.80.Nv, 29.30.-h, 29.90.+r, 87.64.Gb, 07.85.Fv, 29.40.-n, 29.40.Gx, 29.40.Wk 1. Introduction The DAΦNE collider at INFN-LNF1,2 is a unique source of strangeness (kaons) in the world: it delivers low-momentum (< 140 MeV/c) nearly monochromatic charged kaons, generated by the decay of the φ resonance formed in electron-positron annihilation.
    [Show full text]
  • “Unmatter,” As a New Form of Matter, and Its Related “Un-Particle,” “Un-Atom,” “Un-Molecule”
    “Unmatter,” as a new form of matter, and its related “un-particle,” “un-atom,” “un-molecule” Florentin Smarandache has introduced the notion of “unmatter” and related concepts such as “unparticle,” “unatom,” “unmolecule” in a manuscript from 1980 according to the CERN web site, and he uploaded articles about unmatter starting with year 2004 to the CERN site and published them in various journals in 2004, 2005, 2006. In short, unmatter is formed by matter and antimatter that bind together. The building blocks (most elementary particles known today) are 6 quarks and 6 leptons; their 12 antiparticles also exist. Then unmatter will be formed by at least a building block and at least an antibuilding block which can bind together. Keywords: unmatter, unparticle, unatom, unmolecule Abstract. As shown, experiments registered unmatter: a new kind of matter whose atoms include both nucleons and anti-nucleons, while their life span was very short, no more than 10-20 sec. Stable states of unmatter can be built on quarks and anti-quarks: applying the unmatter principle here it is obtained a quantum chromodynamics formula that gives many combinations of unmatter built on quarks and anti-quarks. In the last time, before the apparition of my articles defining “matter, antimatter, and unmatter”, and Dr. S. Chubb’s pertinent comment on unmatter, new development has been made to the unmatter topic in the sense that experiments verifying unmatter have been found.. 1. Definition of Unmatter. In short, unmatter is formed by matter and antimatter that bind together. The building blocks (most elementary particles known today) are 6 quarks and 6 leptons; their 12 antiparticles also exist.
    [Show full text]
  • Exotic Atoms Paul Indelicato
    Exotic atoms Paul Indelicato To cite this version: Paul Indelicato. Exotic atoms. Physica Scripta, IOP Publishing, 2004, T112, pp.20-26. hal-00002825 HAL Id: hal-00002825 https://hal.archives-ouvertes.fr/hal-00002825 Submitted on 11 Sep 2004 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Exotic atoms Paul Indelicato1,∗, 1 Laboratoire Kastler-Brossel, Ecole´ Normale Sup´erieure et Universit´eP. et M. Curie, Case 74, 4 place Jussieu, F-75252, Cedex 05, France Abstract In this paper I review a number of recent results in the field of exotic atoms. Recent experiments or ongoing experiments with muonic, pionic and antiprotonic hydrogen, as well as recent measurement of the pion mass are described. These experiments provide information about nucleon-pion or nucleon- antinucleon interaction as well as information on the proton structure (charge or magnetic moment distribution). PACS numbers: 06.20.Fn, 32.30.Rj, 36.10.-k, 07.85.Nc ccsd-00002825, version 1 - 12 Sep 2004 ∗Email address: [email protected] 1 1 Introduction Exotic atoms are atoms that have captured a long-lived, heavy particle. This particle can be a lepton, sensitive only to the electromagnetic and weak interactions, like the electron or the muon, or a meson like the pion, or a baryon like the antiproton.
    [Show 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.
    [Show full text]
  • Experiments on Exotic Atom Spectroscopy
    Exp eriments on exotic atom sp ectroscopy D Gotta Institut fur Kernphysik Forschungszentrum Julic h D Julic h Germany Abstract Results are reviewed from recent exotic atom exp eriments using a fo cussing Bragg sp ectrometer The measured energies of the L Xrays from antiprotonic hydrogen and deuterium and the K transition from pionic deuterium are compared to the transition ener gies as calculated from quantum electro dynamics in order to determine the strong interaction antiprotonnucleon and pionnucleon scattering parameters at threshold A high precision exp eriment to determine the mass of the charged pion to ppm has b een started by investigat ing the transitions in pionic nitrogen where the o ccurance of Coulomb explosion has b een seen now directly from the Doppler broadening In a forthcoming high precision exp eriment of the pionnucleon scatter ing length new calibration metho ds using an ECR source will b e used to connect energy standards b oth from exotic and electronic atoms Such techniques oer the p ossibility of high precision studies in few electron systems Intro duction Atoms in which the electron shell is replaced partly or in total by other elementary particles of negative charge are called exotic atoms Up to now the systems with muons pions kaons antiprotons and sigma hyp erons have b een established Muonic and pionic atoms are b eing investigated since years at the meson factories of the PaulScherrerInstitut PSI TRI UMF or earlier at LAMPF At CERN in the years until the LowEnergyAntiprotonRing LEAR provided highquality
    [Show full text]
  • Exotic Atoms Are Atoms That Have Captured a Long-Lived, Heavy Particle
    Exotic atoms Paul Indelicato1,∗, 1 Laboratoire Kastler-Brossel, Ecole´ Normale Sup´erieure et Universit´eP. et M. Curie, Case 74, 4 place Jussieu, F-75252, Cedex 05, France Abstract In this paper I review a number of recent results in the field of exotic atoms. Recent experiments or ongoing experiments with muonic, pionic and antiprotonic hydrogen, as well as recent measurement of the pion mass are described. These experiments provide information about nucleon-pion or nucleon- antinucleon interaction as well as information on the proton structure (charge or magnetic moment distribution). PACS numbers: 06.20.Fn, 32.30.Rj, 36.10.-k, 07.85.Nc arXiv:physics/0409058v1 [physics.atom-ph] 12 Sep 2004 ∗Email address: [email protected] 1 1 Introduction Exotic atoms are atoms that have captured a long-lived, heavy particle. This particle can be a lepton, sensitive only to the electromagnetic and weak interactions, like the electron or the muon, or a meson like the pion, or a baryon like the antiproton. An other kind of exotic atom is the one in which the nucleus has been replaced by a positron (positronium, an e+e− bound system) or a positively charged muon (muonium, a µ+e− bound system). Positronium and muonium are pure quantum electrodynamics (QED) systems as they are made of elementary, point-like Dirac particles insensitive to the strong interaction. The annihilation of positronium has been a benchmark of bound-state QED (BSQED) for many years. For a long time there has been an outstanding discrepancy between the calculated (see, e.g., [1] for a recent review) and measured lifetime of ortho-positronium in vacuum, that has been resolved recently [2].
    [Show full text]
  • Exploring the Nature of the Universe
    EXPLORING THE NATURE OF THE UNIVERSE CERN explores the fundamental structure of the universe by operating a sophisticated complex of accelerators that collide beams of particles or direct them onto fixed targets. The results of these collisions are recorded by giant detectors and analysed by thousands of scientists at CERN and beyond. CERN’S ACCELERATOR COMPLEX AND THE productive year for CERN. In addition to the completion of EXPERIMENTS THAT IT FEEDS the process leading to the update of the European Strategy for Particle Physics (see p. 47), 2020 saw many remarkable physics results based on the analysis of data taken The Large Hadron Collider (LHC) is CERN’s flagship before the shutdown by both the LHC and the non-LHC machine. It collides proton beams at the highest energies experiments. The results include the first indications that the ever created, and the results of these collisions are recorded Higgs boson interacts with second-generation particles, the by seven experiments – ALICE, ATLAS, CMS, LHCb, LHCf, observation of a new form of matter–antimatter asymmetry MoEDAL and TOTEM – and soon also by FASER, the newest in strange-beauty particles, and the demonstration of a LHC experiment. The year 2020 was the second year of technique to reveal the dynamics of the strong interaction the Laboratory’s ongoing long shutdown, during which between composite particles called hadrons. It was also a the accelerator complex and experiments are undergoing special year because 30 March 2020 marked ten years of intensive maintenance and upgrade work. However, despite the LHC physics programme, which has seen almost 3000 the shutdown and the COVID-19 pandemic, 2020 was a very scientific papers published by the LHC experiments.
    [Show full text]
  • Exotic Atoms, K-Nucleus Scattering and Hypernuclei
    4. 000-3244-84 EXOTIC ATOMS, K-NUCLEUS SCATTERING AND HYPERNUCLEI . ^ - - 0 - Peter D. Barnes Department of Physics, Camegie-Mel Ion Univer Pittsburgh, Pennsylvania Abstract: Recent progress in exotic atom physics, kaon-nucleus scattering, and hypemuciear physics is reviewed. Specific problems discussed include searches for muon-nucleon interactions beyond Q£D, a comparison of data and recent calculations of K4 + l2C elastic and inelastic scattering, as well as recent studies^of I and A hypemuclei including new data on the level structure of l^CA . 1. Introduction The physical phenomenon discussed in this session consist of exotic atomic and nuclear systems containing bound hadrons and muons as well as the unbound kaon nucleus scattering problem. These topics are both old and new. Whereas exotic atom systems have been discussed for some thirty years, evidence fo^ I hypernudlei, first seen at CERN and now confirmed at BNL, have only become available in the last three years. In this short introductory talk it will not be possible to comment on all the recent developments in these areas. I choose to discuss therefore some selected problems in each of the three areas: a) exotic atom?, b) kaoti nucleus scattering and c) lambda and sigma hypernuclei. 2. Exotic Atoms In this section we consider both mesonic and hadronic atoms. It is useful to classify the systems studied as being in the nuclear regime, the hydrogen-like regime, or the electronic regime according to whether the average size of the atomio orbit is comparable to the nuclear radius, intermediate, or comparable to the electronic orbit.
    [Show full text]
  • Pillar 1 Roadmap CHIPP Workshop Editing
    Pillar 1 roadmap CHIPP workshop editing August 27, 2020 Contents 1 The present Swiss landscape 2 1.1 High energy . .2 1.2 Low energy . .6 2 Major successes (2017-2020) 8 2.1 High energy . .8 2.2 Low energy . 10 3 The international context 11 4 Synergies with other scientific fields 12 4.1 High energy . 12 4.2 Low energy . 13 5 Vision for the future 14 5.1 High energy . 14 5.2 Low energy . 17 1 1 The present Swiss landscape [(5-15 pages) – This section will be very specific to each field. It can be subdivided into research topics and/or per methodology (theoretical versus experimental, laboratory versus field study, and so on). Alternatively, it could be per geographical location, if there are well defined topics covered by different institutions. It shall be as much as possible inclusive of all the community to leave nobody out. It shall also show what are the major topics in Switzerland, which institutes are leaders in specific research areas, and possibly also what is less developed yet (especially if a new infrastructure is foreseen to fill this gap). How strong is the Swiss network: how much do the scientists of different institutes collaborate together? What are the main infrastructures used? Are they accessible to researchers from other institutions? ] 1.1 High energy Swiss institutes are founding members and significant contributors to three of the four high energy physics experiments at CERN: ATLAS (U Bern and U Geneva), CMS (UZH, PSI and ETHZ) and LHCb (EPFL and UZH). The activities of the Swiss scientists have been spanning a very broad spectrum of physics pursuits: from precision measurements of the Standard Model (SM) to explorations of new phenomena that could answer the open questions of our universe.
    [Show full text]
  • Arxiv:0710.5890V1 [Nucl-Th]
    Strange Atoms, Strange Nuclei and Kaon Condensation∗ E. Friedman1, † and A. Gal1, ‡ 1Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel (Dated: August 26, 2021) Abstract Analyses of strong–interaction data consisting of level shifts, widths and yields in strange atoms of K− mesons and Σ− hyperons are reviewed. Recent results obtained by fitting to comprehensive sets of data across the periodic table in terms of density dependent optical potentials are discussed. The introduction of density dependence generally improves significantly the fit to the data, leading to novel results on the in-medium hadron-nucleon t matrix t(ρ) over a wide range of densities up to central nuclear densities. A strongly attractive K−–nuclear potential of order 150–200 MeV in nuclear matter is suggested by fits to K−–atom data, with interesting possible repercussions on K¯ condensation and on the evolution of strangeness in high-density stars. The case for relatively narrow deeply bound K− atomic states is made, essentially independent of the K− potential depth. In view of the recently reported inconclusive experimental signals of K¯ deeply bound states, dynamical models for calculating binding energies and widths of K¯ -nuclear states are discussed. > − Lower bounds on the width, ΓK¯ 50 MeV, are established. For Σ atoms, the fitted potential becomes repulsive inside the nucleus,∼ in agreement with recently reported (π−, K+) spectra from KEK, implying that Σ hyperons generally do not bind in nuclei. This repulsion significantly affects calculated compositions and masses of neutron stars. PACS numbers: 13.75.Jz; 21.80.+a; 25.80.Nv; 26.60.+c; 36.10.Gv Keywords: kaonic atoms; K− deeply bound atomic and nuclear states; kaon condensation; sigmionic atoms; Σ hypernuclei; neutron stars arXiv:0710.5890v1 [nucl-th] 31 Oct 2007 ∗ Lectures delivered by Avraham Gal at the International School of Physics Enrico Fermi, Varenna, June 2007.
    [Show full text]