DOCSLIB.ORG

The Fourth Generation: a Comprehensive Analysis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Fourth Generation: a Comprehensive Analysis TECHNISCHE UNIVERSITAT¨ MUNCHEN¨ Lehrstuhl T31 f¨ur Theoretische Elementarteilchenphysik The Fourth Generation: A Comprehensive Analysis Christoph Promberger Vollst¨andiger Abdruck der von der Fakult¨at f¨ur Physik der Technischen Universit¨at M¨unchen zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. StefanSch¨onert Pr¨ufer der Dissertation: 1. Univ.-Prof. Dr. Andrzej J. Buras 2. Univ.-Prof. Dr. Alejandro Ibarra Die Dissertation wurde am 24.5.2011 bei der Technischen Universit¨at M¨unchen eingereicht und durch die Fakult¨at f¨ur Physik am 6.6.2011 angenommen. Zusammenfassung Gegenstand dieser Arbeit ist eine systematische ph¨anomenologische Analyse der als SM4 bezeichneten Standardmodell-Erweiterung durch eine vierte Generation von Quarks und Leptonen. In diesem Rahmen behandeln wir neben direkten Messungen der beteiligten Parameter vor allem elektroschwache Pr¨azisionstests sowie Flavor- und CP-verletzende Ob- servablen im Quark- wie im Lepton-Sektor. Unsere Analyse elektroschwacher Pr¨azisionstests widerlegt die weit verbreitete Annahme, eine vierte Generation w¨urde durch solche Messungen bereits ausgeschlossen. Allerdings wird der verf¨ugbare Parameterraum dadurch stark eingeschr¨ankt, insbesondere die Misch- ung zwischen Quarks der dritten und vierten Familie sowie die m¨oglichen Massendifferenzen innerhalb der neuen Quark- und Lepton-Duplets. Im Weiteren berechnen wir mehr als 30 Prozesse im Quark- und Lepton-Sektor, in de- nen flavor-¨andernde neutrale Str¨ome und/oder Verletzungen der CP-Symmetrie auftreten. Es wird gezeigt, wie im SM4 die bestehenden Anomalien im Unitarit¨atsdreieck sowie in den CP Asymmetrien Sψφ und SφKS gleichzeitig behoben werden k¨onnen. Eine globale nu- merische Untersuchung aller behandelter Observablen schr¨ankt den Parameterraum weiter ein und offenbart charakteristische Korrelationsmuster zwischen bestimmten Messgr¨oßen. Die hierdurch erhaltenen ph¨anomenologischen Signaturen erlauben es, das SM4 eindeutig von anderen Modellen neuer Physik zu unterscheiden. Abstract The subject of this thesis is a systematic phenomenological analysis of the SM4, the stan- dard model of particle physics extended by a fourth generation of quarks and leptons. In this framework we study the impact of direct measurements of the involved parameters, electroweak precision tests, as well as flavor and CP violation observables in the quark and lepton sector. The analysis of electroweak precision tests disproves the commonly held assumption that a fourth generation would be excluded by these constraints. Yet, they impose severe bounds on the involved parameter space, particularly the quark mixing between the third and fourth family and the possible mass differences within the new quark and lepton doublets. Subsequently, we calculate more than 30 flavor changing neutral current and CP-violating processes in the quark and lepton sector. It is shown how the existing anomalies in the unitarity triangle fits as well as in the CP asymmetries Sψφ and SφKS can be explained simultaneously in the SM4. A global numerical analysis of all calculated observables further constrains the parameter space and reveals characteristic patterns of correlation between certain measurable quantities. The phenomenological signatures obtained in this way allow to clearly distinguish the SM4 from other new physics scenarios. Contents 1. Introduction 3 2. The SM4 9 2.1. ParticlesandProperties ............................. 9 2.1.1. ExtendingtheSM ............................ 9 2.1.2. DirectSearchesandMassLimits . 10 2.1.2.1. Mass Limits for Fourth Generation Quarks . 10 2.1.2.2. Mass Limits for Fourth Generation Leptons . 11 2.1.2.3. UpperMassBoundsfromPerturbativity . 12 2.2. FermionMixing.................................. 12 2.2.1. The 4 4 Quark Mixing Matrix V .................. 13 × SM4 2.2.1.1. Parametrization and Unitarity . 13 2.2.1.2. TreeLevelCKMConstraints . 15 2.2.1.3. Simplifications, Wolfenstein Expansion and Scaling Scenarios 17 2.2.1.4. CP-Violating Invariants . 19 2.2.2. The 4 4 Lepton Mixing Matrix U ................. 20 × SM4 3. Electroweak Precision Tests 23 3.1. Electroweak Precision Observables . ... 23 3.1.1. ObliqueParameters............................ 24 3.1.1.1. GeneralIntroduction. 24 3.1.1.2. Oblique Parameters in the SM4 . 25 3.1.2. Non-Oblique Effects: Zb¯b Vertex .................... 26 3.2. Numerical Analysis of Electroweak Precision Tests in the SM4 . ..... 28 3.2.1. Outline .................................. 28 3.2.2. Bound on s34 ............................... 29 3.2.3. MassSplitting............................... 30 4. Flavor and CP Violation Observables 33 4.1. Preliminaries: Effective Hamiltonians and Loop Functions . ... 33 4.1.1. Introduction to Effective Field Theories . 33 4.1.2. Gauge Independent Loop and Master Functions in the SM4 . .. 34 4.1.2.1. GaugeIndependentLoopFunctions. 35 4.1.2.2. MasterFunctions........................ 35 4.2. Quark Flavor and CP Violation . 37 4.2.1. Particle-Antiparticle Mixing (∆F = 2) and Indirect CP Violation . 37 4.2.1.1. K0 K¯ 0 Mixing (∆S =2)................... 37 − Contents 4.2.1.2. B0 B¯0 Mixing (∆B =2)................... 39 q − q 4.2.1.3. D0 D¯ 0 Mixing (∆C =2)................... 41 − 4.2.2. LeptonicDecays.............................. 42 + 4.2.2.1. KL µ µ− ........................... 42 → + 4.2.2.2. B µ µ− .......................... 43 s,d → 4.2.3. Semi-LeptonicDecays .......................... 45 4.2.3.1. K+ π+νν¯ and K π0νν¯ ................. 45 → L → 4.2.3.2. B X νν¯ ........................... 46 → d,s 4.2.4. RadiativeDecays ............................. 47 4.2.4.1. B Xsγ ............................ 47 → + 4.2.4.2. B Xsℓ ℓ− .......................... 49 → 0 + 4.2.4.3. K π ℓ ℓ− .......................... 49 L → 4.2.5. CP Violation in K and B Decays .................... 51 4.2.5.1. Preliminaries . 51 4.2.5.2. Direct CP Violation in the K system: ε′/ε .......... 51 4.2.5.3. CP-Violating B Decays into CP Eigenstates . 52 4.2.5.4. A (b sγ)intheSM4.................... 56 CP → 4.3. Lepton Flavor Violation . 57 4.3.1. Preliminaries . 57 4.3.2. Dipole Transitions (ℓ ℓ γ) ...................... 57 a → b 4.3.3. Four-LeptonTransitions . 58 + 4.3.3.1. The Decays τ − ℓb−ℓc ℓb− ................... 58 → + 4.3.3.2. The Decays τ − ℓb−ℓc ℓc− ................... 59 → + 4.3.3.3. The Decays ℓ− ℓ−ℓ ℓ− ................... 60 a → b b b 4.3.4. Semi-Leptonic τ Decays ......................... 61 4.3.5. Lepton-Flavor Violating B and K Decays ............... 63 4.3.5.1. K µe and K π0µe ................. 63 L,S → L,S → 4.3.5.2. B ℓ ℓ ........................... 64 q → c d 4.3.6. µ e ConversioninNuclei........................ 65 − 4.3.7. AnomalousMagneticMomentoftheMuon. 66 5. Numerical Analysis 69 5.1. NumericalAnalysisoftheQuarkSector. ... 69 5.1.1. Preliminaries . 69 5.1.2. Violation of Universality . 71 5.1.3. Correlations within the K System.................... 72 5.1.4. Correlations Involving the B System .................. 77 bsγ 5.1.5. The CP Asymmetries Sψφ, SφKS and ACP ............... 79 5.1.6. The Ratio ε′/ε .............................. 81 5.1.7. Violation of CKM Unitarity . 84 5.1.8. Patterns of Correlation and Comparison with other Models . ... 85 5.2. AnatomyoftheQuarkSector . 87 5.2.1. Step1:ParameterScenarios . 87 5.2.2. Step 2: Anticipating LHCb Results . 88 Contents 1 5.3. Determining the Matrix VSM4 .......................... 89 5.3.1. Preliminaries . 89 5.3.2. BasicObservables............................. 91 5.3.3. Anatomyof4GMixingAnglesandCPPhases . 95 5.4. NumericalAnalysisoftheLeptonSector . 102 5.4.1. Preliminaries . 102 + 5.4.2. µ− e−γ, µ− e−e e− and µ e Conversion . 102 5.4.3. The→ Decays τ →µγ and τ eγ−..................... 105 → → 5.4.4. The Semi-Leptonic τ Decays and τ µγ ................ 105 0 → 5.4.5. KL µe and KL π µe ........................ 106 5.4.6. UpperBounds...............................→ → 107 5.4.7. Patterns of Correlation and Comparison with other Models . 108 6. Summary and Conclusions 111 A. Effective FCNC Vertices 115 A.1.GenericEffectiveVertices . 115 A.1.1. GenericBoxVertex.. .. .. 115 A.1.2. Generic Z0 PenguinVertex........................ 117 A.1.3. GenericPhotonPenguinVertex . 118 A.1.3.1. Off-Shell γ Penguin....................... 118 A.1.3.2. On-Shell γ Penguin....................... 119 A.1.4. Generic Gluon Penguin Vertex . 120 A.2. Wilson Coefficients and Gauge-Independent Loop Functions . ...... 120 A.2.1. Wilson Coefficients for ∆F =2FourFermionOperators . 120 A.2.2. Wilson Coefficients for ∆F =1FourFermionOperators . 121 B. Reference: Loop Functions 123 Bibliography 127 Danksagung 146 1. Introduction The world around us is composed of only three types of basic elementary particles: Up- and down-quarks are the principal components of all atomic nuclei, and electrons constitute the atomic shells. In addition, there is the electron neutrino first postulated by Pauli in 1931 [1] and discovered in 1956 [2], which is too volatile to act as a constituent of matter. These four fermions – two quarks and two leptons – comprise what we call today the first generation. The first indication that this is not the end of the story came from the discovery of the muon in 1937 [3,4], which is approximately 200 times heavier than the electron but identical in all other properties. The surprise which this particle caused in the physical community is probably best captured by I.I. Rabi’s famous question: “Who ordered that?” [5]. Throughout the following decades, the
Load more

Recommended publications
  • CERN Courier–Digital Edition
    CERNMarch/April 2021 cerncourier.com COURIERReporting on international high-energy physics WELCOME CERN Courier – digital edition Welcome to the digital edition of the March/April 2021 issue of CERN Courier. Hadron colliders have contributed to a golden era of discovery in high-energy physics, hosting experiments that have enabled physicists to unearth the cornerstones of the Standard Model. This success story began 50 years ago with CERN’s Intersecting Storage Rings (featured on the cover of this issue) and culminated in the Large Hadron Collider (p38) – which has spawned thousands of papers in its first 10 years of operations alone (p47). It also bodes well for a potential future circular collider at CERN operating at a centre-of-mass energy of at least 100 TeV, a feasibility study for which is now in full swing. Even hadron colliders have their limits, however. To explore possible new physics at the highest energy scales, physicists are mounting a series of experiments to search for very weakly interacting “slim” particles that arise from extensions in the Standard Model (p25). Also celebrating a golden anniversary this year is the Institute for Nuclear Research in Moscow (p33), while, elsewhere in this issue: quantum sensors HADRON COLLIDERS target gravitational waves (p10); X-rays go behind the scenes of supernova 50 years of discovery 1987A (p12); a high-performance computing collaboration forms to handle the big-physics data onslaught (p22); Steven Weinberg talks about his latest work (p51); and much more. To sign up to the new-issue alert, please visit: http://comms.iop.org/k/iop/cerncourier To subscribe to the magazine, please visit: https://cerncourier.com/p/about-cern-courier EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING ATLAS spots rare Higgs decay Weinberg on effective field theory Hunting for WISPs CCMarApr21_Cover_v1.indd 1 12/02/2021 09:24 CERNCOURIER www.
    [Show full text]
  • Annual Report — Research Activity
    lavi CONTRACT NO. 35482 net 01/10/2007 — 30/09/2008 Annual Report — Research Activity ———————————————————————————————————- Contents 1 Research Achievements 1 2 Publications 12 3 Conferences, Workshops and General Networking 29 3.1 Euro-Flavour07.................................. 29 3.2 Euro-Flavour08.................................. 31 3.3 Conferences and workshops within FLAVIAnet .................. 33 3.4 Otherconferencesandworkshops . ..... 34 3.5 GeneralNetworking............................... .. 49 3.6 Changestotheschedule. ... 51 4 Economic spin–off 51 5 Conclusions 51 ———————————————————————————————————- We report on the second year of the Marie Curie Research and Training Network FLAVIAnet. The report starts with summaries of the research achievements of the 11 nodes in Sect. 1. In Sect. 2 we list the publications of our network. Sect. 3 describes the presentation of our scientific results at international conferences and describes our networking activity. We discuss the economic spin–off of our research activity in Sect. 4. Finally we conclude. 1 Research Achievements In this section we describe the scientific activity of the nodes with emphasis on the relation to the working groups and to milestones defined in Annex I of the FLAVIAnet contract. Node No. 1: Spain-V (Universitat de Valencia` Estudi General [UVEG]) In collaboration with nodes 9 and 11 [19] a detailed comparison between the results of (quenched) 2 Annual Report — Research Activity lattice QCD and the predictions of (quenched) ChPT at NLO has been performed. In particular, two different chiral regimes (p- and ǫ-regimes) have been considered. Volume and quark mass dependence of current correlators has been studied. In the ǫ regime, also the dependence on the topological charge has been investigated. Finally, the leading order LECs F and Σ have been extracted in the two regimes (milestone no.
    [Show full text]
  • Anatomy and Phenomenology of Flavor and CP Violation in Supersymmetric Theories
    Technische Universit¨atM¨unchen Fakult¨atf¨urPhysik Lehrstuhl f¨urtheoretische Physik IV (T31) Anatomy and Phenomenology of Flavor and CP Violation in Supersymmetric Theories Wolfgang Altmannshofer Vollst¨andigerAbdruck der von der Fakult¨atf¨urPhysik der Technischen Universit¨atM¨unchen zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. Stephan Paul Pr¨uferder Dissertation: 1. Univ.-Prof. Dr. Andrzej J. Buras 2. Hon.-Prof. Dr. Wolfgang F. L. Hollik Die Dissertation wurde am 08.07.2010 bei der Technischen Universit¨atM¨unchen eingereicht und durch die Fakult¨atf¨urPhysik am 20.07.2010 angenommen. Zusammenfassung Gegenstand dieser Doktorarbeit ist eine umfangreiche und systematische Untersuchung von Flavor und CP verletzenden Niederenergieprozessen im Rahmen des MSSM, der minimalen supersymmetrischen Erweiterung des Standard Modells. Supersymmetrische (SUSY) Mod- elle geh¨orenzu den am besten motivierten und am gr¨undlichsten untersuchten Modellen f¨ur Neue Physik (NP). Es wird erwartet, dass die neuen Freiheitsgrade, die die Supersymmetrie vorhersagt, Massen von der Gr¨oßenordnung der TeV Skala besitzen und die direkte Suche nach diesen Teilchen ist eines der Hauptziele am LHC. Ein komplement¨arerAnsatz das MSSM zu testen, besteht in der Untersuchung von Pr¨azisionsobservablen bei niedrigen En- ergien, die durch die virtuellen Effekte der neuen Freiheitsgrade beeinflusst werden k¨onnen. Von besonderer Bedeutung in diesem Zusammenhang sind sogenannte Flavor Changing Neu- tral Current (FCNC) Prozesse, die im Standard Modell nicht auf Tree Niveau vorkommen und deshalb h¨ochst sensitiv auf die Flavorstruktur von NP Modellen sind. Zuerst untersuchen wir modellunabh¨angigNiederenergieprozesse, die eine hohe Sensi- tivit¨atauf die Flavor und CP verletzenden Strukturen besitzen, die im MSSM enthalten sind.
    [Show full text]
  • Training Activity CONTRACT NO
    lavi Training Activity CONTRACT NO. 35482 net Full Term Report 01/10/2006 — 30/09/2010 We report here on the four years of Training and TOK activities of the Marie Curie Research and Training Network FLAVIAnet. The Training and TOK activities have been organized, supervised and coordinated among the several nodes by the FLAVIAnet Training Committee composed by M. Davier (Orsay), S. Descotes Genon (Orsay), P. Krizan (Ljubljana), P. Hernandez (Valencia), T. Mannel (Siegen), C. T. Sachrajda (Southampton) and chaired by N. Brambilla (Technical U. Munich). In the following we report the training and TOK achievements for each of the eleven FLAVIAnet nodes in the period 01/10/2006–30/09/2010. For each one of the Early Stage Researchers (ESR) and each one of the Experienced Researchers (ER) of our network a detailed and personalized Career Development Plan has been constructed by the Network Training Committee in collaboration with the node tutors. In establishing the Career Path for our researchers we have considered a global Career Plan covering both short term and long terms objectives, being the long term ones projected over a period of five years, thus including also the time after the conclusion of this network. The network has been fully committed to grant to the young researcher all the relevant skills and tools to allow them to develop into independent and creative researchers, to enlarge and create their own scientific vision, to make possible that they acquire all the relevant scientific, managerial, leadership and communicational capabilities such to open up different perspectives and opportunities for them in the future.
    [Show full text]
  • Supersymmetric SO(10) Unification and Flavor-Changing Weak Decays
    Physik-Department Technische Universit¨at M¨unchen Institut f¨ur Theoretische Physik Lehrstuhl Univ.-Prof. Dr. Andrzej J. Buras Supersymmetric SO(10) unification and flavor-changing weak decays Sebastian Jager¨ Technische Universit¨at M¨unchen Physik-Department James-Franck-Straße 85748 Garching Germany Email: [email protected] Physik-Department Technische Universit¨at M¨unchen Institut f¨ur Theoretische Physik Lehrstuhl Univ.-Prof. Dr. Andrzej J. Buras Supersymmetric SO(10) unification and flavor-changing weak decays Sebastian Jager¨ Vollst¨andiger Abdruck der von der Fakult¨at f¨ur Physik der Technischen Univer- sit¨at M¨unchen zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. Stefan Paul Pr¨ufer der Dissertation: 1. Univ.-Prof. Dr. Andrzej J. Buras 2. Univ.-Prof. Dr. Manuel Drees Die Dissertation wurde am 9.10.2003 bei der Technischen Universit¨at M¨unchen eingereicht und durch die Fakult¨at f¨ur Physik am 21.10.2003 angenommen. Abstract We study flavor-changing decays of hadrons and leptons in supersymmetric grand unified theories with universal soft-breaking terms at the Planck scale. Specifi- cally, we study an SO(10) model with a flavor structure motivated by the observed large atmospheric mixing angle. In such models, the large top Yukawa coupling leads to a predictive pattern of flavor violation among the sfermion mass matrices both in the slepton and squark sectors. The steps taken are the following. • We perform the first study of this model utilizing a full renormalization- group analysis to relate Planck-scale parameters to weak-scale parameters.
    [Show full text]
  • Gauge Theory of Weak Decays
    Cambridge University Press 978-1-107-03403-7 — Gauge Theories of Weak Decays Andrzej Buras Frontmatter More Information Gauge Theory of Weak Decays This is the first advanced, systematic, and comprehensive look at weak decays in the framework of gauge theories. Included is a large spectrum of topics, both theoretical and experimental. In addition to explicit advanced calculations of Feynman diagrams and the study of renormalization group strong interaction effects in weak decays, the book is devoted to the Standard Model Effective Field Theory, dominating present phenomenology in this field, and to new physics models with the goal of searching for new particles and interactions through quantum fluctuations. This book will benefit theorists, experimental researchers, and PhD students working on flavor physics and weak decays as well as physicists interested in physics beyond the Standard Model. In its concern for the search for new phenomena at short-distance scales through the interplay between theory and experiment, this book constitutes a travel guide to physics far beyond the scales explored by the Large Hadron Collider at CERN. Andrzej J. Buras is one of the most cited particle theorists in Europe and the most cited theoretical flavor physicist worldwide. He has written extensively on weak decays through lecture notes and review articles. He has been awarded the Smoluchowski-Warburg Medal of German and Polish Physics Societies, a Senior Carl von Linde Fellowship at TUM-IAS, an Advanced ERC Grant, and the 2020 Max Planck Medal. He is an ordinary member of the Bavarian Academy of Sciences and foreign member of two Academies in Poland.
    [Show full text]
  • Annual Report 1 TUM Institute for Advanced Study 2007 | 2008
    Annual Report 1 TUM Institute for Advanced Study 2007 | 2008 Annual Report TUM Institute for Advanced Study 2 0 0 7 | 2 0 0 8 Table of Contents Table of Contents Foreword of TUM President 4 Director’s Message 6 Presentation of TUM-IAS 11 Presentation of Fellows and Focus Groups 25 Experience Report 73 Events 79 New Building and Concept 101 Resources and Data 104 Organization 106 4 Foreword of TUM President The “TUM Institute for Advanced Study” (TUM-IAS), founded in 2005, was the centerpiece of the Excellence Initiative proposal, “TUM. The Entrepreneurial University”. Much like the legendary IAS in Princeton, TUM-IAS is based on the assumption that an atmosphere of creativity, inspiration, freedom, and support - without a lot of red tape - for excellent researchers forms the most productive source for outstanding scientific achievements. The goal of the Institute for Advanced Study is to establish new fields of excellence in research at TUM. The TUM-IAS gives scientists from TUM and from abroad the time and resources to focus on new, cutting-edge research, and is therefore a key to fostering scientific excellence at TUM. Very often our most gifted scientists are burdened by bureaucracy in their daily work. The Institute brings top scientists from TUM and distinguished international scientists together with the most promising young scholars in a community where intellectual creativity can flourish and young crea- tive minds can exchange ideas with established leaders. Three years after the founding of the TUM-IAS, I am very pleased to see that the Institute is already thriving with 19 Fellows and numerous start- up projects.
    [Show full text]
  • DEPARTMENT of PHYSICS COLLOQUIA Fall 1999 Schedule
    DEPARTMENT OF PHYSICS COLLOQUIA Fall 1999 Schedule August 30 Randall D. Kamien - University of Pennsylvania Title: Liquid Crystalline Phases of DNA September 6 Sara A. Solla – Northwestern University Title: The Dynamics of Learning from Examples September 13 Anton Zeilinger - University of Vienna, Austria Title: Quantum Teleportation and the Nature of Information September 20 – The Thomas Gold Lecture Series Bohdan Paczynski – Princeton University Title: Gravitational Microlensing and the Search for Dark Matter September 27 Carlos Rovelli – University of Pittsburgh and Centre de Physique Theorique de Luminy, France Title: Non Perturbative Quantum Gravity October 4 Eric Siggia – Cornell University Title: Theory and the Yeast Genome October 11 – FALL BREAK October 18 Edward Blucher – University of Chicago Title: Investigating Difference between Matter and Antimatter October 25 Venky Narayanamurti – Harvard University Title: Condensed-Matter and Materials Physics: Basic Research for Tomorrow’s Technology November 1 – The Kieval Lecture Steve Vogel – Duke University Title: Locating Life’s Limits with Dimensionless Numbers November 8 Edward Kearns – Boston University Title: The Mysteries of Missing Neutrino’s: Latest Results from Super-K November 15 Paul Steinhardt – University of Pennsylvania Title: The Quintessential Universe November 22 Dan Ralph – Cornell University Title: Torques and Tunneling in Nano-Magnets November 29 William Phillips – NIST Title: Almost Absolute Zero: The Story of Laser Cooling and Trapping Spring 2000 Schedule January
    [Show full text]
  • Looking at Physics in a Rarefied Atmosphere
    RARE PROCESSES Looking at physics in a rarefied atmosphere Last year the annual DESYTheory Workshop focused on rare physics - the physics that's hardest to do and sometimes difficult to understand. AndrzejBuras reports. Rare processes and the vio­ 5xl0~4and 30xl04. lation of CP symmetry pro­ As discussed by Guido vided the focus for the Martinelli (Rome), Laurent recent Theory Workshop at Leilouch (Marseille) and the DESY Laboratory in Amarjit Soni (Brookhaven), Hamburg.As emphasized by advanced numerical lattice Chris Quigg (Fermilab) in calculations could consider­ the opening lecture, discrete ably improve the estimates symmetries (box 1) and in the coming years. How­ their violation, in particular ever, as stressed by Jamin, CP symmetry, play an impor­ it is important to develop tant role in a deeper under­ further the existing analyti­ standing of nature at both cal tools in order to confront very small and large dis­ the lattice results. tances. Studying these vio­ lations in rare processes Difficult measurements may give hints to what lies The experimental situation beyond the Standard Model for e/e, described by Martin of particle physics. Holder (Siegen), improved In the Standard Model, Relaxed atmosphere during the break. Left to right: Luca Silvestrini considerably in the past two CP violation is attributed to (Rome), chairman of the organizing comittee Andrzej Bums (Munich), years due to measurements quark transitions, which are Yosef Nir (Weizmann) and Gino Isidori (Frascati). by the KTeV collaboration at described by the three- Fermilab (28 ± 4) xlO"4 and dimensional (Cabbibo-Kobayashi-Maskawa; CKM) matrix.The clas­ the NA48 collaboration at CERN (14±4)xl0~4.
    [Show full text]
  • Warsaw Conference of the 1996 Rochester Conference
    Warsaw University's Auditorium Maximum provided the location for the parallel sessions Warsaw conference of the 1996 Rochester conference. n recent years, the biennial I "Rochester" International Conference on High Energy Physics has been a festival of the Standard Model, the 20-year-old set of theories describing particles and forces. Despite early expectations to the contrary, the 28th in this prestigious series, held in Warsaw in July, turned out to be true to form. In 1995, after many years of increasingly accurate measurements agreeing ever more precisely with Standard Model predictions, some small discrepancies appeared. Theoreticians lost no time in invoking explanations involving physics beyond the Standard Model. The most popular of these is supersymmetry, a theory linking particles and forces which introduces a new "supersymmetric" partner for each ordinary particle. The atmos­ phere was charged with anticipation for new physics. But by the time the on the so-called Rb anomaly from the Andrzej Buras of Munich Technical 1996 Rochester came around, most Aleph and L3 experiments University homed in on CP violation, of the discrepancies had gone away, respectively at CERN's Large the mechanism believed to be leaving the Standard Model healthier Electron-Positron Collider, LEP. Rh responsible for the apparent absence than it has been for some time. is the fraction of quark-producing Z of antimatter in the Universe. He The mood of the conference was decays resulting in pairs of heavy looked forward to the new precision captured by Gabriele Veneziano, b-quarks. Last year, results from measurement of direct CP violation head of CERN's Theory Division, LEP seemed to indicate that this expected soon from CERN's NA48 with his concluding remarks that "The happened far too often (October experiment.
    [Show full text]
  • Heavy Flavour Physics and Effective Field Theories Alexander Lenz
    Heavy Flavour Physics and Effective Field Theories Epiphany 2015 An inspiring example of Heavy Flavour Alexander Lenz IPPP Durham July 10, 2015 1 2 Contents 1 Introduction 7 1.1 Thestandardmodelinarealnutshell. 7 1.2 Massesoftheelementaryparticles . 8 1.3 Outline ............................... 10 2 FlavourPhysicsandtheCKMmatrix 11 2.1 Heavyhadrons ........................... 11 2.2 Weakdecaysofheavyquarks. 12 2.3 Weakdecaysofheavyhadrons . 15 2.4 Exercise1.............................. 16 2.5 CKM,FCNC,...withintheSM . 18 2.6 ExerciseII: ............................. 26 2.7 Acluetoexplainexistence . 26 2.7.1 ElectroweakBaryogenesis . 28 2.7.2 GUT-Baryogenesis. 31 2.7.3 Leptogenesis........................ 32 2.8 CPviolation............................. 32 3 Flavour phenomenology 33 3.1 Overview .............................. 33 3.2 Theunitaritytriangle . 34 3.3 Flavourexperiments. 36 3.4 Currentstatusofflavourphenomenology. 39 4 Weak decays I - Basics 42 4.1 Themyondecay........................... 42 4.2 Thetaudecay ............................ 43 4.3 Mesondecays-Definitions . 44 4.4 Charm-quarkdecay . .. .. .. .. .. .. 46 4.5 Bottom-quarkdecay. 48 5 Weak decays II - The effective Hamiltonian 51 5.1 Motivation.............................. 51 5.2 TheeffectiveHamiltonianinLO-QCD . 54 5.2.1 Basics-Feynmanrules. 54 5.2.2 Theinitialconditions. 58 5.2.3 Matching:.......................... 61 5.2.4 Therenormalisationgroupevolution . 64 5.3 TheeffectiveHamiltonianinNLOandNNLO-QCD . 68 3 6 Weak decays III - Inclusive B-decays 69 6.1 InclusiveB-decaysatLO-QCD. 69 6.2 Bsl and nc atNLO-QCD ...................... 70 7 The Heavy Quark Expansion 72 7.1 Calculationofinclusivedecayrates . 72 7.2 Theexpansionininversemasses . 72 7.3 LeadingtermintheHQE . 73 7.4 SecondtermoftheHQE . .. .. .. .. .. .. 75 7.5 ThirdtermoftheHQE ....................... 78 7.6 FourthtermoftheHQE. 83 7.7 Violationofquark-hadronduality . 84 7.8 Statusoflifetimepredictions . 84 7.8.1 B-mesonlifetimes . .. .. .. .. .. .. 84 7.8.2 b-baryonlifetimes . 85 7.8.3 D-mesonlifetimes .
    [Show full text]
  • Ccnn COURIER International Journal of High Energy Physics History of CERN, III Edited by J
    ccnn COURIER International journal of high energy physics History of CERN, III Edited by J. Krige "The present volume continues the story of the history of CERN, concentrating on the years between the • mid 1960s and the late 1970s, Contents: Part I. Interactions. CERN from the mid-1960s to tie late 1970s (1 Krige). Gargamelle and BEBC How Europe's last two giant bubble chambers were chosen (D. Pestre). The difficult decision, taken in the 1960s, to construct a 3-400 GeV proton synchrotron in Europe (D, Pestre), The intersecting storage rings. The construction and operation of CERN's second large machine and a survey of its experimental programme. The relationship between CERN and its Visitors' in the 1970s (J. Krige), The ppbar project I, The collider (I Krige), The ppbar project It The organization of experimental work (J. Krige). Part 11 Physics Results. Physics in the CERN theory division (J. Hiopoubs). The SC: Isolde and nuclear structure {G> Hansen), Experimental studies of weak interactions (K. Winter), Part III, Technologies. The development of accelerator art and expertise at CERN: 1960-1980. Twenty fruitful years (M. CrowieyMlling), The development of electronic position detectors at CERN (1964 - late 1970s) (I Gambaro). Name index. Subject index. 1996 700pages Price: NLG 375.00 (US$234,50) Hardbound ISBN0*444*896554 ALREADY PUBLISHED: History of CERN, II History of CERN, I Volume II - Building and Running the Volume I - Launching the European Laboratory, 1954-1965 Organization for Nuclear Research By A. Hermann, J. Krige, U. Mersits and By A. Hermann, J. Krige, U. Mersits and D.
    [Show full text]