Measurement of the Mass and the Quantum Numbers J of the X(3872)
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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. -
Qcd in Heavy Quark Production and Decay
QCD IN HEAVY QUARK PRODUCTION AND DECAY Jim Wiss* University of Illinois Urbana, IL 61801 ABSTRACT I discuss how QCD is used to understand the physics of heavy quark production and decay dynamics. My discussion of production dynam- ics primarily concentrates on charm photoproduction data which is compared to perturbative QCD calculations which incorporate frag- mentation effects. We begin our discussion of heavy quark decay by reviewing data on charm and beauty lifetimes. Present data on fully leptonic and semileptonic charm decay is then reviewed. Mea- surements of the hadronic weak current form factors are compared to the nonperturbative QCD-based predictions of Lattice Gauge The- ories. We next discuss polarization phenomena present in charmed baryon decay. Heavy Quark Effective Theory predicts that the daugh- ter baryon will recoil from the charmed parent with nearly 100% left- handed polarization, which is in excellent agreement with present data. We conclude by discussing nonleptonic charm decay which are tradi- tionally analyzed in a factorization framework applicable to two-body and quasi-two-body nonleptonic decays. This discussion emphasizes the important role of final state interactions in influencing both the observed decay width of various two-body final states as well as mod- ifying the interference between Interfering resonance channels which contribute to specific multibody decays. "Supported by DOE Contract DE-FG0201ER40677. © 1996 by Jim Wiss. -251- 1 Introduction the direction of fixed-target experiments. Perhaps they serve as a sort of swan song since the future of fixed-target charm experiments in the United States is A vast amount of important data on heavy quark production and decay exists for very short. -
Mean Lifetime Part 3: Cosmic Muons
MEAN LIFETIME PART 3: MINERVA TEACHER NOTES DESCRIPTION Physics students often have experience with the concept of half-life from lessons on nuclear decay. Teachers may introduce the concept using M&M candies as the decaying object. Therefore, when students begin their study of decaying fundamental particles, their understanding of half-life may be at the novice level. The introduction of mean lifetime as used by particle physicists can cause confusion over the difference between half-life and mean lifetime. Students using this activity will develop an understanding of the difference between half-life and mean lifetime and the reason particle physicists prefer mean lifetime. Mean Lifetime Part 3: MINERvA builds on the Mean Lifetime Part 1: Dice which uses dice as a model for decaying particles, and Mean Lifetime Part 2: Cosmic Muons which uses muon data collected with a QuarkNet cosmic ray muon detector (detector); however, these activities are not required prerequisites. In this activity, students access authentic muon data collected by the Fermilab MINERvA detector in order to determine the half-life and mean lifetime of these fundamental particles. This activity is based on the Particle Decay activity from Neutrinos in the Classroom (http://neutrino-classroom.org/particle_decay.html). STANDARDS ADDRESSED Next Generation Science Standards Science and Engineering Practices 4. Analyzing and interpreting data 5. Using mathematics and computational thinking Crosscutting Concepts 1. Patterns 2. Cause and Effect: Mechanism and Explanation 3. Scale, Proportion, and Quantity 4. Systems and System Models 7. Stability and Change Common Core Literacy Standards Reading 9-12.7 Translate quantitative or technical information . -
X. Charge Conjugation and Parity in Weak Interactions →
Charge conjugation and parity in weak interactions Particle Physics X. Charge conjugation and parity in weak interactions REMINDER: Parity The parity transformation is the transformation by reflection: → xi x'i = –xi A parity operator Pˆ is defined as Pˆ ψ()()xt, = pψ()–x, t where p = +1 Charge conjugation The charge conjugation replaces particles by their antiparticles, reversing charges and magnetic moments ˆ Ψ Ψ C a = c a where c = +1 meaning that from the particle in the initial state we go to the antiparticle in the final state. Oxana Smirnova & Vincent Hedberg Lund University 248 Charge conjugation and parity in weak interactions Particle Physics Reminder Symmetries Continuous Lorentz transformation Space-time Translation in space Symmetries Translation in time Rotation around an axis Continuous transformations that can Space-time be regarded as a series of infinitely small steps. symmetries Discrete Parity Transformations that affects the Space-time Charge conjugation space-- and time coordinates i.e. transformation of the 4-vector Symmetries Time reversal Minkowski space. Discrete transformations have only two elements i.e. two transformations. Baryon number Global Lepton number symmetries Strangeness number Isospin SU(2)flavour Internal The transformation does not depend on Isospin+Hypercharge SU(3)flavour symmetries r i.e. it is the same everywhere in space. Transformations that do not affect the space- and time- Local gauge Electric charge U(1) coordinates. symmetries Weak charge+weak isospin U(1)xSU(2) Colour SU(3) The -
Study of the Higgs Boson Decay Into B-Quarks with the ATLAS Experiment - Run 2 Charles Delporte
Study of the Higgs boson decay into b-quarks with the ATLAS experiment - run 2 Charles Delporte To cite this version: Charles Delporte. Study of the Higgs boson decay into b-quarks with the ATLAS experiment - run 2. High Energy Physics - Experiment [hep-ex]. Université Paris Saclay (COmUE), 2018. English. NNT : 2018SACLS404. tel-02459260 HAL Id: tel-02459260 https://tel.archives-ouvertes.fr/tel-02459260 Submitted on 29 Jan 2020 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. Study of the Higgs boson decay into b-quarks with the ATLAS experiment run 2 These` de doctorat de l’Universite´ Paris-Saclay prepar´ ee´ a` Universite´ Paris-Sud Ecole doctorale n◦576 Particules, Hadrons, Energie,´ Noyau, Instrumentation, Imagerie, NNT : 2018SACLS404 Cosmos et Simulation (PHENIICS) Specialit´ e´ de doctorat : Physique des particules These` present´ ee´ et soutenue a` Orsay, le 19 Octobre 2018, par CHARLES DELPORTE Composition du Jury : Achille STOCCHI Universite´ Paris Saclay (LAL) President´ Giovanni MARCHIORI Sorbonne Universite´ (LPNHE) Rapporteur Paolo MERIDIANI Universite´ de Rome (INFN), CERN Rapporteur Matteo CACCIARI Universite´ Paris Diderot (LPTHE) Examinateur Fred´ eric´ DELIOT Universite´ Paris Saclay (CEA) Examinateur Jean-Baptiste DE VIVIE Universite´ Paris Saclay (LAL) Directeur de these` Daniel FOURNIER Universite´ Paris Saclay (LAL) Invite´ ` ese de doctorat Th iii Synthèse Le Modèle Standard fournit un modèle élégant à la description des particules élémentaires, leurs propriétés et leurs interactions. -
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. -
Measurement of Production and Decay Properties of Bs Mesons Decaying Into J/Psi Phi with the CMS Detector at the LHC
University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 5-2012 Measurement of Production and Decay Properties of Bs Mesons Decaying into J/Psi Phi with the CMS Detector at the LHC Giordano Cerizza University of Tennessee - Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Elementary Particles and Fields and String Theory Commons Recommended Citation Cerizza, Giordano, "Measurement of Production and Decay Properties of Bs Mesons Decaying into J/Psi Phi with the CMS Detector at the LHC. " PhD diss., University of Tennessee, 2012. https://trace.tennessee.edu/utk_graddiss/1279 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Giordano Cerizza entitled "Measurement of Production and Decay Properties of Bs Mesons Decaying into J/Psi Phi with the CMS Detector at the LHC." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Physics. Stefan M. Spanier, Major Professor We have read this dissertation and recommend its acceptance: Marianne Breinig, George Siopsis, Robert Hinde Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Measurements of Production and Decay Properties of Bs Mesons Decaying into J/Psi Phi with the CMS Detector at the LHC A Thesis Presented for The Doctor of Philosophy Degree The University of Tennessee, Knoxville Giordano Cerizza May 2012 c by Giordano Cerizza, 2012 All Rights Reserved. -
Charge Conjugation Symmetry
Charge Conjugation Symmetry In the previous set of notes we followed Dirac's original construction of positrons as holes in the electron's Dirac sea. But the modern point of view is rather different: The Dirac sea is experimentally undetectable | it's simply one of the aspects of the physical ? vacuum state | and the electrons and the positrons are simply two related particle species. Moreover, the electrons and the positrons have exactly the same mass but opposite electric charges. Many other particle species exist in similar particle-antiparticle pairs. The particle and the corresponding antiparticle have exactly the same mass but opposite electric charges, as well as other conserved charges such as the lepton number or the baryon number. Moreover, the strong and the electromagnetic interactions | but not the weak interactions | respect the change conjugation symmetry which turns particles into antiparticles and vice verse, C^ jparticle(p; s)i = jantiparticle(p; s)i ; C^ jantiparticle(p; s)i = jparticle(p; s)i ; (1) − + + − for example C^ e (p; s) = e (p; s) and C^ e (p; s) = e (p; s) . In light of this sym- metry, deciding which particle species is particle and which is antiparticle is a matter of convention. For example, we know that the charged pions π+ and π− are each other's an- tiparticles, but it's up to our choice whether we call the π+ mesons particles and the π− mesons antiparticles or the other way around. In the Hilbert space of the quantum field theory, the charge conjugation operator C^ is a unitary operator which squares to 1, thus C^ 2 = 1 =) C^ y = C^ −1 = C^:; (2) ? In condensed matter | say, in a piece of semiconductor | we may detect the filled electron states by making them interact with the outside world. -
Identification of Boosted Higgs Bosons Decaying Into B-Quark
Eur. Phys. J. C (2019) 79:836 https://doi.org/10.1140/epjc/s10052-019-7335-x Regular Article - Experimental Physics Identification of boosted Higgs bosons decaying into b-quark pairs with the ATLAS detector at 13 TeV ATLAS Collaboration CERN, 1211 Geneva 23, Switzerland Received: 27 June 2019 / Accepted: 23 September 2019 © CERN for the benefit of the ATLAS collaboration 2019 Abstract This paper describes a study of techniques for and angular distribution of the jet constituents consistent with identifying Higgs bosons at high transverse momenta decay- a two-body decay and containing two b-hadrons. The tech- ing into bottom-quark pairs, H → bb¯, for proton–proton niques described in this paper to identify Higgs bosons decay- collision data collected by the ATLAS detector√ at the Large ing into bottom-quark pairs have been used successfully in Hadron Collider at a centre-of-mass energy s = 13 TeV. several analyses [8–10] of 13 TeV proton–proton collision These decays are reconstructed from calorimeter jets found data recorded by ATLAS. with the anti-kt R = 1.0 jet algorithm. To tag Higgs bosons, In order to identify, or tag, boosted Higgs bosons it is a combination of requirements is used: b-tagging of R = 0.2 paramount to understand the details of b-hadron identifica- track-jets matched to the large-R calorimeter jet, and require- tion and the internal structure of jets, or jet substructure, in ments on the jet mass and other jet substructure variables. The such an environment [11]. The approach to tagging√ presented Higgs boson tagging efficiency and corresponding multijet in this paper is built on studies from LHC runs at s = 7 and and hadronic top-quark background rejections are evaluated 8 TeV, including extensive studies of jet reconstruction and using Monte Carlo simulation. -
Decay Rates and Cross Section
Decay rates and Cross section Ashfaq Ahmad National Centre for Physics Outlines Introduction Basics variables used in Exp. HEP Analysis Decay rates and Cross section calculations Summary 11/17/2014 Ashfaq Ahmad 2 Standard Model With these particles we can explain the entire matter, from atoms to galaxies In fact all visible stable matter is made of the first family, So Simple! Many Nobel prizes have been awarded (both theory/Exp. side) 11/17/2014 Ashfaq Ahmad 3 Standard Model Why Higgs Particle, the only missing piece until July 2012? In Standard Model particles are massless =>To explain the non-zero mass of W and Z bosons and fermions masses are generated by the so called Higgs mechanism: Quarks and leptons acquire masses by interacting with the scalar Higgs field (amount coupling strength) 11/17/2014 Ashfaq Ahmad 4 Fundamental Fermions 1st generation 2nd generation 3rd generation Dynamics of fermions described by Dirac Equation 11/17/2014 Ashfaq Ahmad 5 Experiment and Theory It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong. Richard P. Feynman A theory is something nobody believes except the person who made it, An experiment is something everybody believes except the person who made it. Albert Einstein 11/17/2014 Ashfaq Ahmad 6 Some Basics Mandelstam Variables In a two body scattering process of the form 1 + 2→ 3 + 4, there are 4 four-vectors involved, namely pi (i =1,2,3,4) = (Ei, pi) Three Lorentz Invariant variables namely s, t and u are defined. -
And G-Parity: a New Definition and Applications —Version Viib—
BNL PREPRINT BNL-QGS-13-0901 Cparity7b.tex C- and G-parity: A New Definition and Applications |Version VIIb| S. U. Chung α Physics Department Brookhaven National Laboratory, Upton, NY 11973, U.S.A. β Department of Physics Pusan National University, Busan 609-735, Republic of Korea γ and Excellence Cluster Universe Physik Department E18, Technische Universit¨atM¨unchen,Germany δ September 29, 2013 abstract A new definition for C (charge-conjugation) and G operations is proposed which allows for unique value of the C parity for each member of a given J PC nonet. A simple straightforward extension of the definition allows quarks to be treated on an equal footing. As illustrative examples, the problems of constructing eigenstates of C, I and G operators are worked out for ππ, KK¯ , NN¯ and qq¯ systems. In particular, a thorough treatment of two-, three- and four-body systems involving KK¯ systems is given. α CERN Visiting Scientist (part time) β Senior Scientist Emeritus γ Research Professor (part time) δ Scientific Consultant (part time) 1 Introduction The purpose of this note is to point out that the C operation can be defined in such a way that a unique value can be assigned to all the members of a given J PC nonet. In conventional treatments in which antiparticle states are defined through C, one encounters the problem that anti-particle states do not transform in the same way (the so-called charge-conjugate representation). That this is so is obvious if one considers the fact that a C operation changes sign of the z-component of the I-spin, so that in general C and I operators do not commute. -
Arxiv:1706.02588V2 [Hep-Ph] 29 Apr 2019 D D O Oeua Tts Ntehde Hr Etrw Have We Sector Candidates Charm Good Hidden the Particularly the in As Are States
Heavy Baryon-Antibaryon Molecules in Effective Field Theory 1, 2 1, 1, Jun-Xu Lu, Li-Sheng Geng, ∗ and Manuel Pavon Valderrama † 1School of Physics and Nuclear Energy Engineering, International Research Center for Nuclei and Particles in the Cosmos and Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University, Beijing 100191, China 2Institut de Physique Nucl´eaire, CNRS-IN2P3, Univ. Paris-Sud, Universit´eParis-Saclay, F-91406 Orsay Cedex, France (Dated: April 30, 2019) We discuss the effective field theory description of bound states composed of a heavy baryon and antibaryon. This framework is a variation of the ones already developed for heavy meson- antimeson states to describe the X(3872) or the Zc and Zb resonances. We consider the case of heavy baryons for which the light quark pair is in S-wave and we explore how heavy quark spin symmetry constrains the heavy baryon-antibaryon potential. The one pion exchange potential mediates the low energy dynamics of this system. We determine the relative importance of pion exchanges, in particular the tensor force. We find that in general pion exchanges are probably non- ¯ ¯ ¯ ¯ ¯ ¯ perturbative for the ΣQΣQ, ΣQ∗ ΣQ and ΣQ∗ ΣQ∗ systems, while for the ΞQ′ ΞQ′ , ΞQ∗ ΞQ′ and ΞQ∗ ΞQ∗ cases they are perturbative. If we assume that the contact-range couplings of the effective field theory are saturated by the exchange of vector mesons, we can estimate for which quantum numbers it is more probable to find a heavy baryonium state. The most probable candidates to form bound states are ¯ ¯ ¯ ¯ ¯ ¯ the isoscalar ΛQΛQ, ΣQΣQ, ΣQ∗ ΣQ and ΣQ∗ ΣQ∗ and the isovector ΛQΣQ and ΛQΣQ∗ systems, both in the hidden-charm and hidden-bottom sectors.