Compton Scattering Sum Rules for Massive Vector Bosons
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“Revista Istorică”, XXVIII, 2017, Nos. 1-2
“Revista istorică”, XXVIII, 2017, nos. 1-2 ABSTRACTS THE ARABS AND THE MONGOLS EXPANDING: A COMPARISON OF THE PREMISES VIRGIL CIOCÎLTAN The route from the nomad’s tent to the imperial palace had the same starting ground, namely the disadvantaged areas, which made their nomadic inhabitants particularly receptive to material gains, and the same finality: expansion and the formation of the two empires. Beyond the specific means of achieving each course individually, their essence was identical: the politic and social instability, which was endemic to the gentile societies of pre-Islamic Arabia and Mongolia before the rule of Genghis Khan, was removed by the great social and political renewals of the 7th, respectively the 12th century, which presented the nomadic inhabitants with a new identity, granted them social homogeneity and integrated them into state structures which superseded the traditional tribal entities. As the conscience of being Moslem transgressed the narrow gentile differences and allowed the formation of the great Islamic community (umma), composed of equal elements, at least in theory, which were unified precisely by the common faith in Allah, so Genghis Khan’s reform, promulgated at the 1206 kurultai, consecrated the victory of the new identity, that of members of the Mongol ulus, which was also of divine right and with similar universal imperial traits. Thereupon, the energies previously consumed in internal conflicts could be harnessed and channeled towards the outer world, where they produced epochal military victories. The analogy between these phenomena and those produced several centuries later by the French Revolution, which made possible, through a similar process of equalization, the “mass uprising” (levée en masse) and, as a consequence, Napoleon’s great conquests, is striking. -
The Story of Large Electron Positron Collider 1
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Publications of the IAS Fellows GENERAL ç ARTICLE The Story of Large Electron Positron Collider 1. Fundamental Constituents of Matter S N Ganguli I nt roduct ion The story of the large electron positron collider, in short LEP, is linked intimately with our understanding of na- ture'sfundamental particlesand theforcesbetween them. We begin our story by giving a brief account of three great discoveries that completely changed our thinking Som Ganguli is at the Tata Institute of Fundamental and started a new ¯eld we now call particle physics. Research, Mumbai. He is These discoveries took place in less than three years currently participating in an during 1895 to 1897: discovery of X-rays by Wilhelm experiment under prepara- Roentgen in 1895, discovery of radioactivity by Henri tion for the Large Hadron Becquerel in 1896 and the identi¯cation of cathode rays Collider (LHC) at CERN, Geneva. He has been as electrons, a fundamental constituent of atom by J J studying properties of Z and Thomson in 1897. It goes without saying that these dis- W bosons produced in coveries were rewarded by giving Nobel Prizes in 1901, electron-positron collisions 1903 and 1906, respectively. X-rays have provided one at the Large Electron of the most powerful tools for investigating the struc- Positron Collider (LEP). During 1970s and early ture of matter, in particular the study of molecules and 1980s he was studying crystals; it is also an indispensable tool in medical diag- production and decay nosis. -
Triple Vector Boson Production at the LHC
Triple Vector Boson Production at the LHC Dan Green Fermilab - CMS Dept. ([email protected]) Introduction The measurement of the interaction among vector bosons is crucial to understanding electroweak symmetry breaking. Indeed, data from LEP-II have already determined triple vector boson couplings and a first measurement of quartic couplings has been made [1]. It is important to explore what additional information can be supplied by future LHC experiments. One technique is to use “tag” jets to identify vector boson fusion processes leading to two vector bosons and two tag jets in the final state. [2] However, the necessity of two quarks simultaneously radiating a W boson means that the cross section is rather small. Another approach is to study the production of three vector bosons in the final state which are produced by the Drell- Yan mechanism. There is a clear tradeoff, in that valence-valence processes are not allowed, which limits the mass range which can be explored using this mechanism, although the cross sections are substantially larger than those for vector boson fusion. Triple Vector Boson Production A Z boson decaying into lepton pairs is required in the final state in order to allow for easy triggering at the LHC and to insure a clean sample of Z plus four jets. Possible final states are ZWW, ZWZ and ZZZ. Assuming that the second and third bosons are reconstructed from their decay into quark pairs, the W and Z will not be easily resolved given the achievable dijet mass resolution. Therefore, the final states of interest contain a Z which decays into leptons and four jets arising for the quark decays of the other two vector bosons. -
12 from Neutral Currents to Weak Vector Bosons
12 From neutral currents to weak vector bosons The unification of weak and electromagnetic interactions, 1973{1987 Fermi's theory of weak interactions survived nearly unaltered over the years. Its basic structure was slightly modified by the addition of Gamow-Teller terms and finally by the determination of the V-A form, but its essence as a four fermion interaction remained. Fermi's original insight was based on the analogy with elec- tromagnetism; from the start it was clear that there might be vector particles transmitting the weak force the way the photon transmits the electromagnetic force. Since the weak interaction was of short range, the vector particle would have to be heavy, and since beta decay changed nuclear charge, the particle would have to carry charge. The weak (or W) boson was the object of many searches. No evidence of the W boson was found in the mass region up to 20 GeV. The V-A theory, which was equivalent to a theory with a very heavy W , was a satisfactory description of all weak interaction data. Nevertheless, it was clear that the theory was not complete. As described in Chapter 6, it predicted cross sections at very high energies that violated unitarity, the basic principle that says that the probability for an individual process to occur must be less than or equal to unity. A consequence of unitarity is that the total cross section for a process with 2 angular momentum J can never exceed 4π(2J + 1)=pcm. However, we have seen that neutrino cross sections grow linearly with increasing center of mass energy. -
The Standard Model Part II: Charged Current Weak Interactions I
Prepared for submission to JHEP The Standard Model Part II: Charged Current weak interactions I Keith Hamiltona aDepartment of Physics and Astronomy, University College London, London, WC1E 6BT, UK E-mail: [email protected] Abstract: Rough notes on ... Introduction • Relation between G and g • F W Leptonic CC processes, ⌫e− scattering • Estimated time: 3 hours ⇠ Contents 1 Charged current weak interactions 1 1.1 Introduction 1 1.2 Leptonic charge current process 9 1 Charged current weak interactions 1.1 Introduction Back in the early 1930’s we physicists were puzzled by nuclear decay. • – In particular, the nucleus was observed to decay into a nucleus with the same mass number (A A) and one atomic number higher (Z Z + 1), and an emitted electron. ! ! – In such a two-body decay the energy of the electron in the decay rest frame is constrained by energy-momentum conservation alone to have a unique value. – However, it was observed to have a continuous range of values. In 1930 Pauli first introduced the neutrino as a way to explain the observed continuous energy • spectrum of the electron emitted in nuclear beta decay – Pauli was proposing that the decay was not two-body but three-body and that one of the three decay products was simply able to evade detection. To satisfy the history police • – We point out that when Pauli first proposed this mechanism the neutron had not yet been discovered and so Pauli had in fact named the third mystery particle a ‘neutron’. – The neutron was discovered two years later by Chadwick (for which he was awarded the Nobel Prize shortly afterwards in 1935). -
Vector Boson Scattering Processes: Status and Prospects
Vector Boson Scattering Processes: Status and Prospects Diogo Buarque Franzosi (ed.)g,d, Michele Gallinaro (ed.)h, Richard Ruiz (ed.)i, Thea K. Aarrestadc, Mauro Chiesao, Antonio Costantinik, Ansgar Dennert, Stefan Dittmaierf, Flavia Cetorellil, Robert Frankent, Pietro Govonil, Tao Hanp, Ashutosh V. Kotwala, Jinmian Lir, Kristin Lohwasserq, Kenneth Longc, Yang Map, Luca Mantanik, Matteo Marchegianie, Mathieu Pellenf, Giovanni Pellicciolit, Karolos Potamianosn,Jurgen¨ Reuterb, Timo Schmidtt, Christopher Schwanm, Michał Szlepers, Rob Verheyenj, Keping Xiep, Rao Zhangr aDepartment of Physics, Duke University, Durham, NC 27708, USA bDeutsches Elektronen-Synchrotron (DESY) Theory Group, Notkestr. 85, D-22607 Hamburg, Germany cEuropean Organization for Nuclear Research (CERN) CH-1211 Geneva 23, Switzerland dDepartment of Physics, Chalmers University of Technology, Fysikgården 1, 41296 G¨oteborg, Sweden eSwiss Federal Institute of Technology (ETH) Z¨urich, Otto-Stern-Weg 5, 8093 Z¨urich, Switzerland fUniversit¨atFreiburg, Physikalisches Institut, Hermann-Herder-Straße 3, 79104 Freiburg, Germany gPhysics Department, University of Gothenburg, 41296 G¨oteborg, Sweden hLaborat´oriode Instrumenta¸c˜aoe F´ısicaExperimental de Part´ıculas(LIP), Lisbon, Av. Prof. Gama Pinto, 2 - 1649-003, Lisboa, Portugal iInstitute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego, Cracow 31-342, Poland jUniversity College London, Gower St, Bloomsbury, London WC1E 6BT, United Kingdom kCentre for Cosmology, Particle Physics and Phenomenology (CP3), Universit´eCatholique de Louvain, Chemin du Cyclotron, B-1348 Louvain la Neuve, Belgium lMilano - Bicocca University and INFN, Piazza della Scienza 3, Milano, Italy mTif Lab, Dipartimento di Fisica, Universit`adi Milano and INFN, Sezione di Milano, Via Celoria 16, 20133 Milano, Italy nDepartment of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK oDipartimento di Fisica, Universit`adi Pavia, Via A. -
Basic Ideas of the Standard Model
BASIC IDEAS OF THE STANDARD MODEL V.I. ZAKHAROV Randall Laboratory of Physics University of Michigan, Ann Arbor, Michigan 48109, USA Abstract This is a series of four lectures on the Standard Model. The role of conserved currents is emphasized. Both degeneracy of states and the Goldstone mode are discussed as realization of current conservation. Remarks on strongly interact- ing Higgs fields are included. No originality is intended and no references are given for this reason. These lectures can serve only as a material supplemental to standard textbooks. PRELIMINARIES Standard Model (SM) of electroweak interactions describes, as is well known, a huge amount of exper- imental data. Comparison with experiment is not, however, the aspect of the SM which is emphasized in present lectures. Rather we treat SM as a field theory and concentrate on basic ideas underlying this field theory. Th Standard Model describes interactions of fields of various spins and includes spin-1, spin-1/2 and spin-0 particles. Spin-1 particles are observed as gauge bosons of electroweak interactions. Spin- 1/2 particles are represented by quarks and leptons. And spin-0, or Higgs particles have not yet been observed although, as we shall discuss later, we can say that scalar particles are in fact longitudinal components of the vector bosons. Interaction of the vector bosons can be consistently described only if it is highly symmetrical, or universal. Moreover, from experiment we know that the corresponding couplings are weak and can be treated perturbatively. Interaction of spin-1/2 and spin-0 particles are fixed by theory to a much lesser degree and bring in many parameters of the SM. -
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. -
Phenomenology Lecture 6: Higgs
Phenomenology Lecture 6: Higgs Daniel Maître IPPP, Durham Phenomenology - Daniel Maître The Higgs Mechanism ● Very schematic, you have seen/will see it in SM lectures ● The SM contains spin-1 gauge bosons and spin- 1/2 fermions. ● Massless fields ensure: – gauge invariance under SU(2)L × U(1)Y – renormalisability ● We could introduce mass terms “by hand” but this violates gauge invariance ● We add a complex doublet under SU(2) L Phenomenology - Daniel Maître Higgs Mechanism ● Couple it to the SM ● Add terms allowed by symmetry → potential ● We get a potential with infinitely many minima. ● If we expend around one of them we get – Vev which will give the mass to the fermions and massive gauge bosons – One radial and 3 circular modes – Circular modes become the longitudinal modes of the gauge bosons Phenomenology - Daniel Maître Higgs Mechanism ● From the new terms in the Lagrangian we get ● There are fixed relations between the mass and couplings to the Higgs scalar (the one component of it surviving) Phenomenology - Daniel Maître What if there is no Higgs boson? ● Consider W+W− → W+W− scattering. ● In the high energy limit ● So that we have Phenomenology - Daniel Maître Higgs mechanism ● This violate unitarity, so we need to do something ● If we add a scalar particle with coupling λ to the W ● We get a contribution ● Cancels the bad high energy behaviour if , i.e. the Higgs coupling. ● Repeat the argument for the Z boson and the fermions. Phenomenology - Daniel Maître Higgs mechanism ● Even if there was no Higgs boson we are forced to introduce a scalar interaction that couples to all particles proportional to their mass. -
Alexandru Proca
ALEXANDRU PROCA (1897–1955) Dorin POENARU Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH), Bucharest-Magurele, Romania and Frankfurt Institute for Advanced Studies (FIAS), J W Goethe University, Frankfurt am Main, Germany CLUSTER CD Dorin N. POENARU, IFIN-HH DECAYS A. Proca (1897–1955) – p.1/34 OUTLINE • Chronology • Impact on various branches of theoretical physics • Particles • Relativistic quantum fields • Klein-Gordon fields • Dirac field • Maxwell and Proca field • Hideki Yukawa and the Strong interaction • Einstein-Proca gravity. Dark matter, black holes. Tachyons. CLUSTER CD Dorin N. POENARU, IFIN-HH DECAYS A. Proca (1897–1955) – p.2/34 Chronology I • 1897 October 16: born in Bucharest • 1915 Graduate of the Gheorghe Lazar high school • 1917–18 Military School and 1st world war • 1918–22 student Polytechnical School (PS), Electromechanics • 1922–23 Engineer Electrical Society, Câmpina, and assistant professor of Electricity, PS Bucharest • 1923 Move to France: “I have something to say in Physics” • 1925 Graduate of Science Faculty, Sorbonne University, Paris CLUSTER CD Dorin N. POENARU, IFIN-HH DECAYS A. Proca (1897–1955) – p.3/34 Chronology II • 1925–27 researcher, Institut du Radium. Appreciated by Marie Curie • 1930–31 French citizen. L. de Broglie’s PhD student. Marie Berthe Manolesco became his wife • 1931–33 Boursier de Recherches, Institut Henri Poincaré • 1933 PhD thesis. Commission: Jean Perrin, L. Brillouin, L. de Broglie. Chargé de Recherches. After many years Proca will be Directeur de Recherches • 1934 One year with E. Schrödinger in Berlin and few months with N. Bohr in Copenhagen (met Heisenberg and Gamow) CLUSTER CD Dorin N. -
Charged Current Anti-Neutrino Interactions in the Nd280 Detector
CHARGED CURRENT ANTI-NEUTRINO INTERACTIONS IN THE ND280 DETECTOR BRYAN E. BARNHART HIGH ENERGY PHYSICS UNIVERSITY OF COLORADO AT BOULDER ADVISOR: ALYSIA MARINO Abstract. For the neutrino beamline oscillation experiment Tokai to Kamioka, the beam is clas- sified before oscillation by the near detector complex. The detector is used to measure the flux of different particles through the detector, and compare them to Monte Carlo Simulations. For this work, theν ¯µ background of the detector was isolated by examining the Monte Carlo simulation and determining cuts which removed unwanted particles. Then, a selection of the data from the near detector complex underwent the same cuts, and compared to the Monte Carlo to determine if the Monte Carlo represented the data distribution accurately. The data was found to be consistent with the Monte Carlo Simulation. Date: November 11, 2013. 1 Bryan E. Barnhart University of Colorado at Boulder Advisor: Alysia Marino Contents 1. The Standard Model and Neutrinos 4 1.1. Bosons 4 1.2. Fermions 5 1.3. Quarks and the Strong Force 5 1.4. Leptons and the Weak Force 6 1.5. Neutrino Oscillations 7 1.6. The Relative Neutrino Mass Scale 8 1.7. Neutrino Helicity and Anti-Neutrinos 9 2. The Tokai to Kamioka Experiment 9 2.1. Japan Proton Accelerator Research Complex 10 2.2. The Near Detector Complex 12 2.3. The Super-Kamiokande Detector 17 3. Isolation of the Anti-Neutrino Component of Neutrino Beam 19 3.1. Experiment details 19 3.2. Selection Cuts 20 4. Cut Descriptions 20 4.1. Beam Data Quality 20 4.2. -
Raportul Științific Al Centrului Alexandru Proca 2013-2019
Cuprins al Raportului Științific 2013-2019 1.Scurt istoric 2.Strategia Centrului Alexandru Proca. 3.Temele științifice abordate 4.Membrii Centrului Alexandru Proca în perioada 2013-2017 și performanțele obținute 5.Sinteza participarii la diferite competiții. 6.Evenimente științifice organizate de catre Centrul Alexandru Proca 7.Lucrari științifice comunicate 8.Lucrari publicate 10.Propuneri de brevete 11.Propuneri de teme noi A1. Manifestul Centrului Alexandru Proca. A2.Biografia savantului Alexandru Proca Albumul cu imagini al Centrului Alexandru Proca A3.Regulamentul de functionare al Centrului Alexandru Proca 1.Scurt istoric Centrul Alexandru Proca de iniţiere in cercetarea ştiinţifică a elevilor de liceu a împlinit în septembrie anul acesta 6 ani de la înfiinţarea oficială . Practic el a fost înființat în septembrie 2013 , dar prima echipă formată din Ștefan Iov și Alexandru Glonțaru a început activitatea ( cu tema privind studiul adezivului de păianjen) în toamna lui 2012 , iar prima performanță notabilă a fost medalia de argint in mai 2013 la Olimpiada de proiecte de cercetare INESPO 2013 din Olanda. Cînd în toamna anului 2013, pe 13 septembrie mai precis, a fost înfiinţat primul centru de excelenţă pentru iniţierea tinerilor în cercetarea ştiinţifică de pe lîngă INCDIE - CA (Institutul Naţional de Cercetare Dezvoltare în Ingineria Electrică- Cercetări Avansate) ,mulţi din cei prezenţi (majoritatea cercetători ştiinţifici), vedeau o mare utopie într-un astfel de demers dacă nu cumva (aşa cum am auzit în discuţii pe la colţuri );