72. Production and Decay of B-Flavored Hadrons
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BABAR Studies Matter-Antimatter Asymmetry in Τ Lepton Decays
BABAR studies matter-antimatter asymmetry in τττ lepton decays Humans have wondered about the origin of matter since the dawn of history. Physicists address this age-old question by using particle accelerators to recreate the conditions that existed shortly after the Big Bang. At an accelerator, energy is converted into matter according to Einstein’s famous energy-mass relation, E = mc 2 , which offers an explanation for the origin of matter. However, matter is always created in conjunction with the same amount of antimatter. Therefore, the existence of matter – and no antimatter – in the universe indicates that there must be some difference, or asymmetry, between the properties of matter and antimatter. Since 1999, physicists from the BABAR experiment at SLAC National Accelerator Laboratory have been studying such asymmetries. Their results have solidified our understanding of the underlying micro-world theory known as the Standard Model. Despite its great success in correctly predicting the results of laboratory experiments, the Standard Model is not the ultimate theory. One indication for this is that the matter-antimatter asymmetry allowed by the Standard Model is about a billion times too small to account for the amount of matter seen in the universe. Therefore, a primary quest in particle physics is to search for hard evidence for “new physics”, evidence that will point the way to the more complete theory beyond the Standard Model. As part of this quest, BABAR physicists also search for cracks in the Standard Model. In particular, they study matter-antimatter asymmetries in processes where the Standard Model predicts that asymmetries should be very small or nonexistent. -
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. -
Reconstruction of Semileptonic K0 Decays at Babar
Reconstruction of Semileptonic K0 Decays at BaBar Henry Hinnefeld 2010 NSF/REU Program Physics Department, University of Notre Dame Advisor: Dr. John LoSecco Abstract The oscillations observed in a pion composed of a superposition of energy states can provide a valuable tool with which to examine recoiling particles produced along with the pion in a two body decay. By characterizing these oscillation in the D+ ! π+ K0 decay we develop a technique that can be applied to other similar decays. The neutral kaons produced in the D+ ! π+ K0 decay are generated in flavor eigenstates due to their production via the weak force. Kaon flavor eigenstates differ from kaon mass eigenstates so the K0 can be equally represented as a superposition of mass 0 0 eigenstates, labelled KS and KL. Conservation of energy and momentum require that the recoiling π also be in an entangled superposition of energy states. The K0 flavor can be determined by 0 measuring the lepton charge in a KL ! π l ν decay. A central difficulty with this method is the 0 accurate reconstruction of KLs in experimental data without the missing information carried off by the (undetected) neutrino. Using data generated at the Stanford Linear Accelerator (SLAC) and software created as part of the BaBar experiment I developed a set of kinematic, geometric, 0 and statistical filters that extract lists of KL candidates from experimental data. The cuts were first developed by examining simulated Monte Carlo data, and were later refined by examining 0 + − 0 trends in data from the KL ! π π π decay. -
Pion and Kaon Structure at 12 Gev Jlab and EIC
Pion and Kaon Structure at 12 GeV JLab and EIC Tanja Horn Collaboration with Ian Cloet, Rolf Ent, Roy Holt, Thia Keppel, Kijun Park, Paul Reimer, Craig Roberts, Richard Trotta, Andres Vargas Thanks to: Yulia Furletova, Elke Aschenauer and Steve Wood INT 17-3: Spatial and Momentum Tomography 28 August - 29 September 2017, of Hadrons and Nuclei INT - University of Washington Emergence of Mass in the Standard Model LHC has NOT found the “God Particle” Slide adapted from Craig Roberts (EICUGM 2017) because the Higgs boson is NOT the origin of mass – Higgs-boson only produces a little bit of mass – Higgs-generated mass-scales explain neither the proton’s mass nor the pion’s (near-)masslessness Proton is massive, i.e. the mass-scale for strong interactions is vastly different to that of electromagnetism Pion is unnaturally light (but not massless), despite being a strongly interacting composite object built from a valence-quark and valence antiquark Kaon is also light (but not massless), heavier than the pion constituted of a light valence quark and a heavier strange antiquark The strong interaction sector of the Standard Model, i.e. QCD, is the key to understanding the origin, existence and properties of (almost) all known matter Origin of Mass of QCD’s Pseudoscalar Goldstone Modes Exact statements from QCD in terms of current quark masses due to PCAC: [Phys. Rep. 87 (1982) 77; Phys. Rev. C 56 (1997) 3369; Phys. Lett. B420 (1998) 267] 2 Pseudoscalar masses are generated dynamically – If rp ≠ 0, mp ~ √mq The mass of bound states increases as √m with the mass of the constituents In contrast, in quantum mechanical models, e.g., constituent quark models, the mass of bound states rises linearly with the mass of the constituents E.g., in models with constituent quarks Q: in the nucleon mQ ~ ⅓mN ~ 310 MeV, in the pion mQ ~ ½mp ~ 70 MeV, in the kaon (with s quark) mQ ~ 200 MeV – This is not real. -
A Successful Start to Preparations for the Babar Experiment
In June this year, the first part of new collider A successful called PEP-II was commissioned. It will be used in an experiment to observe a rare effect start to in particle physics that could explain why there appears to be only matter and not antimatter in the Universe. The effect is preparations called CP violation, and the experiment will measure for the first time subtle differences in for the BaBar the way fundamental particles called B mesons and their antiparticles decay. experiment According to theory, particles and their antimatter partners should behave like exact mirror images of each other. However, the B by Professor Mike Green mesons and their antiparticles are predicted Royal Holloway, University of London to break this mirror symmetry by a tiny amount. Extract taken from the PPARC Annual Report 1996-97 The so-called BaBar experiment (so named because the symbol for the anti-B meson is a letter 'B' with a bar across the top, and permission was obtained from the author of Babar the Elephant for the use of his name!) takes advantage of the 3-kilometre-long Stanford Linear Accelerator in California which creates and accelerates beams of electrons and their antiparticles, positrons. The beams are then injected into PEP-II. This consists of two concentric rings, 2 kilometres across, which will store the separate beams of electrons and positrons. In the rings, the beams travel close to the speed of light under the influence of electric and magnetic fields which accelerate, guide and focus the beams. The ring being used to store electrons was already in existence, and that is the one which has just been commissioned. -
1.1. Introduction the Phenomenon of Positron Annihilation Spectroscopy
PRINCIPLES OF POSITRON ANNIHILATION Chapter-1 __________________________________________________________________________________________ 1.1. Introduction The phenomenon of positron annihilation spectroscopy (PAS) has been utilized as nuclear method to probe a variety of material properties as well as to research problems in solid state physics. The field of solid state investigation with positrons started in the early fifties, when it was recognized that information could be obtained about the properties of solids by studying the annihilation of a positron and an electron as given by Dumond et al. [1] and Bendetti and Roichings [2]. In particular, the discovery of the interaction of positrons with defects in crystal solids by Mckenize et al. [3] has given a strong impetus to a further elaboration of the PAS. Currently, PAS is amongst the best nuclear methods, and its most recent developments are documented in the proceedings of the latest positron annihilation conferences [4-8]. PAS is successfully applied for the investigation of electron characteristics and defect structures present in materials, magnetic structures of solids, plastic deformation at low and high temperature, and phase transformations in alloys, semiconductors, polymers, porous material, etc. Its applications extend from advanced problems of solid state physics and materials science to industrial use. It is also widely used in chemistry, biology, and medicine (e.g. locating tumors). As the process of measurement does not mostly influence the properties of the investigated sample, PAS is a non-destructive testing approach that allows the subsequent study of a sample by other methods. As experimental equipment for many applications, PAS is commercially produced and is relatively cheap, thus, increasingly more research laboratories are using PAS for basic research, diagnostics of machine parts working in hard conditions, and for characterization of high-tech materials. -
Qt7r7253zd.Pdf
Lawrence Berkeley National Laboratory Recent Work Title RELATIVISTIC QUARK MODEL BASED ON THE VENEZIANO REPRESENTATION. II. GENERAL TRAJECTORIES Permalink https://escholarship.org/uc/item/7r7253zd Author Mandelstam, Stanley. Publication Date 1969-09-02 eScholarship.org Powered by the California Digital Library University of California Submitted to Physical Review UCRL- 19327 Preprint 7. z RELATIVISTIC QUARK MODEL BASED ON THE VENEZIANO REPRESENTATION. II. GENERAL TRAJECTORIES RECEIVED LAWRENCE RADIATION LABORATORY Stanley Mandeistam SEP25 1969 September 2, 1969 LIBRARY AND DOCUMENTS SECTiON AEC Contract No. W7405-eng-48 TWO-WEEK LOAN COPY 4 This is a Library Circulating Copy whIch may be borrowed for two weeks. for a personal retention copy, call Tech. Info. Dlvislon, Ext. 5545 I C.) LAWRENCE RADIATION LABORATOR SLJ-LJ UNIVERSITY of CALIFORNIA BERKELET DISCLAIMER This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor the Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or the Regents of the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof or the Regents of the University of California. -
Hadrons and Nuclei Abstract
Hadrons and Nuclei William Detmold (editor),1 Robert G. Edwards (editor),2 Jozef J. Dudek,2, 3 Michael Engelhardt,4 Huey-Wen Lin,5 Stefan Meinel,6, 7 Kostas Orginos,2, 3 and Phiala Shanahan1 (USQCD Collaboration) 1Massachusetts Institute of Technology 2Jefferson Lab 3College of William and Mary 4New Mexico State University 5Michigan State University 6University of Arizona 7RIKEN BNL Research Center Abstract This document is one of a series of whitepapers from the USQCD collaboration. Here, we discuss opportunities for lattice QCD calculations related to the structure and spectroscopy of hadrons and nuclei. An overview of recent lattice calculations of the structure of the proton and other hadrons is presented along with prospects for future extensions. Progress and prospects of hadronic spectroscopy and the study of resonances in the light, strange and heavy quark sectors is summarized. Finally, recent advances in the study of light nuclei from lattice QCD are addressed, and the scope of future investigations that are currently envisioned is outlined. 1 CONTENTS Executive summary3 I. Introduction3 II. Hadron Structure4 A. Charges, radii, electroweak form factors and polarizabilities4 B. Parton Distribution Functions5 1. Moments of Parton Distribution Functions6 2. Quasi-distributions and pseudo-distributions6 3. Good lattice cross sections7 4. Hadronic tensor methods8 C. Generalized Parton Distribution Functions8 D. Transverse momentum-dependent parton distributions9 E. Gluon aspects of hadron structure 11 III. Hadron Spectroscopy 13 A. Light hadron spectroscopy 14 B. Heavy quarks and the XYZ states 20 IV. Nuclear Spectroscopy, Interactions and Structure 21 A. Nuclear spectroscopy 22 B. Nuclear Structure 23 C. Nuclear interactions 26 D. -
Chapter 3 the Fundamentals of Nuclear Physics Outline Natural
Outline Chapter 3 The Fundamentals of Nuclear • Terms: activity, half life, average life • Nuclear disintegration schemes Physics • Parent-daughter relationships Radiation Dosimetry I • Activation of isotopes Text: H.E Johns and J.R. Cunningham, The physics of radiology, 4th ed. http://www.utoledo.edu/med/depts/radther Natural radioactivity Activity • Activity – number of disintegrations per unit time; • Particles inside a nucleus are in constant motion; directly proportional to the number of atoms can escape if acquire enough energy present • Most lighter atoms with Z<82 (lead) have at least N Average one stable isotope t / ta A N N0e lifetime • All atoms with Z > 82 are radioactive and t disintegrate until a stable isotope is formed ta= 1.44 th • Artificial radioactivity: nucleus can be made A N e0.693t / th A 2t / th unstable upon bombardment with neutrons, high 0 0 Half-life energy protons, etc. • Units: Bq = 1/s, Ci=3.7x 1010 Bq Activity Activity Emitted radiation 1 Example 1 Example 1A • A prostate implant has a half-life of 17 days. • A prostate implant has a half-life of 17 days. If the What percent of the dose is delivered in the first initial dose rate is 10cGy/h, what is the total dose day? N N delivered? t /th t 2 or e Dtotal D0tavg N0 N0 A. 0.5 A. 9 0.693t 0.693t B. 2 t /th 1/17 t 2 2 0.96 B. 29 D D e th dt D h e th C. 4 total 0 0 0.693 0.693t /th 0.6931/17 C. -
Flavour Physics
May 21, 2015 0:29 World Scientific Review Volume - 9in x 6in submit page 1 TASI Lectures on Flavor Physics Zoltan Ligeti Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 ∗E-mail: [email protected] These notes overlap with lectures given at the TASI summer schools in 2014 and 2011, as well as at the European School of High Energy Physics in 2013. This is primarily an attempt at transcribing my hand- written notes, with emphasis on topics and ideas discussed in the lec- tures. It is not a comprehensive introduction or review of the field, nor does it include a complete list of references. I hope, however, that some may find it useful to better understand the reasons for excitement about recent progress and future opportunities in flavor physics. Preface There are many books and reviews on flavor physics (e.g., Refs. [1; 2; 3; 4; 5; 6; 7; 8; 9]). The main points I would like to explain in these lectures are: • CP violation and flavor-changing neutral currents (FCNC) are sen- sitive probes of short-distance physics, both in the standard model (SM) and in beyond standard model (BSM) scenarios. • The data taught us a lot about not directly seen physics in the past, and are likely crucial to understand LHC new physics (NP) signals. • In most FCNC processes BSM/SM ∼ O(20%) is still allowed today, the sensitivity will improve to the few percent level in the future. arXiv:1502.01372v2 [hep-ph] 19 May 2015 • Measurements are sensitive to very high scales, and might find unambiguous signals of BSM physics, even outside the LHC reach. -
Incomplete Document
Improved measurement of the Pseudoscalar Decay Constants fDS from D∗+ γµ+ ν data sample s → Abstract + − Determination of fDS using 14 million e e cc¯ events obtained with the CLEO → II and CLEO II.V detector is presented. New measurement of the branching ratio gives Γ (D+ µ+ν)/Γ (D+ φπ+) = 0.137 0.013 0.022. Using Γ (D+ µ+ν) = 0.036 S → S → ± ± S → 0.09, fDS was calculated and found to be (247 12 20 31) MeV. Comparison ± ± ± ± of these results with other theoretical and experimental results are also presented. 1 Introduction Purely leptonic decay modes of heavy mesons predict their decay constants, which is connected with measured quantities such as CKM matrix elements. Currently it is not possible to measure fB experimentally, but measurements of the Cabibbo-flavor pseudoscalar decay constants such as fDS is possible. This measurement provides a check of these theoretical calculations and helps to establish different theoretical models. + The decay width of Ds is given by [1] G2 m2 Γ(D+ ℓ+ν)= F f 2 m2M 1 ℓ V 2 (1) s 6π DS ℓ DS 2 cs → − MDS ! | | where MDS is the Ds mass, mℓ is the mass of the final state lepton, Vcs is a CKM matrix element equal to 0.974 [2] and GF is the Fermi coupling constant. Various theoretical predictions of fDS range from 190 MeV to 350 MeV. The relative widths of three lepton flavors are 10 : 1 : 10−5 for tau, muon and electron respectively. Helicity suppression reduces smaller width for low mass electron. -
Three Lectures on Meson Mixing and CKM Phenomenology
Three Lectures on Meson Mixing and CKM phenomenology Ulrich Nierste Institut f¨ur Theoretische Teilchenphysik Universit¨at Karlsruhe Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany I give an introduction to the theory of meson-antimeson mixing, aiming at students who plan to work at a flavour physics experiment or intend to do associated theoretical studies. I derive the formulae for the time evolution of a neutral meson system and show how the mass and width differences among the neutral meson eigenstates and the CP phase in mixing are calculated in the Standard Model. Special emphasis is laid on CP violation, which is covered in detail for K−K mixing, Bd−Bd mixing and Bs−Bs mixing. I explain the constraints on the apex (ρ, η) of the unitarity triangle implied by ǫK ,∆MBd ,∆MBd /∆MBs and various mixing-induced CP asymmetries such as aCP(Bd → J/ψKshort)(t). The impact of a future measurement of CP violation in flavour-specific Bd decays is also shown. 1 First lecture: A big-brush picture 1.1 Mesons, quarks and box diagrams The neutral K, D, Bd and Bs mesons are the only hadrons which mix with their antiparticles. These meson states are flavour eigenstates and the corresponding antimesons K, D, Bd and Bs have opposite flavour quantum numbers: K sd, D cu, B bd, B bs, ∼ ∼ d ∼ s ∼ K sd, D cu, B bd, B bs, (1) ∼ ∼ d ∼ s ∼ Here for example “Bs bs” means that the Bs meson has the same flavour quantum numbers as the quark pair (b,s), i.e.∼ the beauty and strangeness quantum numbers are B = 1 and S = 1, respectively.