Around the Laboratories

Total Page：16

File Type：pdf, Size：1020Kb

Around the Laboratories The UA2 experiment at CERN's proton- antiproton Collider - big companion for a series of smaller studies. (Photo CERN 84.9.81) CERN Two more Collider experiments The unique physics conditions provided by the SPS proton- antiproton Collider (see also page 229) are explored by experiments jiounted in the two large underground areas where the beams of protons and antiprotons are brought together. In one underground site sits the mighty UA1 detector, described as the most complicated piece of electronics in the world. The other is the home of the UA2 detector which complemented UA1 in the famous hunt for the W and Z particles (see November 1983 issue, page 370). In this second underground area, UA2 alternates with the UA5 visual detector which provides a fast survey of new collision conditions (see May install silicon/lead sandwich the same behaviour also occurs at issue, page 131). detectors in UA4's 'Roman Pots' to small angles. (The UA6 experiment at the detect the photons coming from After UA7 completes its running Collider works in a different way, the decay of neutral pions which this year, a new experiment, UA8, providing its own protons in the emerge from the proton- by a Los Angeles (UCLA) group form of a jet of hydrogen gas antiproton collisions close to the will install a new 'mini-drift' wire which squirts across the path of collision axis. chamber system in the Roman the circulating antiprotons - see UA1 and UA5 have revealed pots vacated by UA7. The UA8 April issue, page 102.) interesting suggestions of new team will look at the special In the same underground area behaviour in the numbers of 'diffractive' reactions which as the large UA2 apparatus is charged particles emerging from produce a fast forward proton (or another experiment - UA4 the collisions. These suggestions antiproton) together with large (Amsterdam/CERN/Genoa/Naples/ are interpreted by some as hints transverse energy which may be Pisa) - which studies elastic of the onset at SPS Collider in the form of 'jets'. The fast scattering, when the colliding protons and antiprotons 'bounce' energies of a long-awaited change forward particle will be detected in off each other like billiard balls of phase when matter containing the wire chamber system, as was (see October 1984 issue, page particles 'boils', producing matter done by UA4, while the transverse 336). containing quarks and gluons (see, energy will be picked up by Its initial aims accomplished, for example, the article by W. courtesy of UA2's large detector. UA4 will serve as a springboard Willis in the January/February The fast forward particle most for UA7 - a brief new study this 1982 issue, page 179). Clues have likely contains the three valence fall by a Naples/Japan group of been seen with particles coming quarks (antiquarks) of the beam neutral pions produced along the off at large angles to the collision proton (antiproton). Therefore, the collision axis. The UA7 team will axis, and it is important to check if particles with transverse energy CERN Courier, July/August 1985 237 .

Copy Link

Recommended publications

PRODUCTION of HIGH MASS Cv and E'e' PAIRS in the UA2
142 PRODUCTION OF HIGH MASS cv AND e'e' PAIRS IN THE UA2 EXPERIMENT AT THE CERN pp COLLIDER The UA2 Collaboration (Berne, CERN, CopenhagenT Orsay;" Pavía, Sacïay) Dî 84100S6163 presented by J. SCHACHER University of Berne, Switzerland ABSTRACT We present new results on intermediate vector boson production at the CERN pp collider. A comparison is made with the predictions of the standard model of the unified electroweak Glashow-Salam-Weinberg theory. - 143 - 1, INTRODUCTION We report here the results from a search for electrons with > 15 GeV/c produced at the CERN pp collider (Vs = 540 GeV) during its 1982 and 1983 periods of operation. Following a general discussion of the topology of the events containing an electron candidate, we shall compare the data with expectations in the framework of the electroweak standard model [1] for the reactions p + p - W~ + anything (1) - e" • v (?) p • p - Z° + anything (2) -* e* + e" or e* + e" + y where W~ and Z° are the postulated charged and neutral Intermediate Vector Bosonc (IVB), respectively, According to the amount of data collected we are now in the position to study some details of the IVB production, e.g. the influence of emission of gluon radiation on the distribution of the W transverse momentum (Fig.1). Fig.l Typical diagram for W and Z production, taking into account emission of gluon (g) radiation. 7T : parton in p or p. - 144 - Preliminary results from the study reported here have already been presented elsewhere [2] and a more complete discussion can be found in a recent publication [3].
[Show full text]
Fabiola Gianotti
Fabiola Gianotti Date of Birth 29 October 1960 Place Rome, Italy Nomination 18 August 2020 Field Physics Title Director-General of the European Laboratory for Particle Physics, CERN, Geneva Most important awards, prizes and academies Honorary Professor, University of Edinburgh; Corresponding or foreign associate member of the Italian Academy of Sciences (Lincei), the National Academy of Sciences of the United States, the French Academy of Sciences, the Royal Society London, the Royal Academy of Sciences and Arts of Barcelona, the Royal Irish Academy and the Russian Academy of Sciences. Honorary doctoral degrees from: University of Uppsala (2012); Ecole Polytechnique Federale de Lausanne (2013); McGill University, Montreal (2014); University of Oslo (2014); University of Edinburgh (2015); University of Roma Tor Vergata (2017); University of Chicago (2018); University Federico II, Naples (2018); Université de Paris Sud, Orsay (2018); Université Savoie Mont Blanc, Annecy (2018); Weizmann Institute, Israel (2018); Imperial College, London (2019). National honours: Cavaliere di Gran Croce dell'Ordine al Merito della Repubblica, awarded by the Italian President Giorgio Napolitano (2014). Special Breakthrough Prize in Fundamental Physics (shared, 2013); Enrico Fermi Prize of the Italian Physical Society (shared, 2013); Medal of Honour of the Niels Bohr Institute, Copenhagen (2013); Wilhelm Exner Medal, Vienna (2017); Tate Medal of the American Institute of Physics for International Leadership (2019). Summary of scientific research Fabiola Gianotti is a particle physicist working at high-energy accelerators. In her scientific career, she has made significant contributions to several experiments at CERN, including UA2 at the proton-antiproton collider (SpbarpS), ALEPH at the Large Electron-Positron collider (LEP) and ATLAS at the Large Hadron Collider (LHC).
[Show full text]
Standard Model and Measurements of Its Parameters (Like the Mass of the Top Quark) at Hadron Colliders Are Presented
Title: Physics at Hadron Colliders Lecturer: Dr Karl Jakobs Date and Times: 1st August at 11:15 2nd August at 10:15 3rd August at 10:15 3rd August at 11:15 Summary of the proposed talk: Present and future hadron colliders play an important role in the investigation of fundamental questions of particle physics. After an introductory lecture, tests of the Standard Model and measurements of its parameters (like the mass of the top quark) at hadron colliders are presented. In addition, it will be discussed how the Higgs boson can be searched for at hadron colliders and how "New Physics", i.e. physics beyond the Standard Model, can be explored. Results are presented from the currently ongoing run at the Tevatron proton antiproton collider at the US research lab Fermilab. In addition, the rich physics potential of the experiments at the CERN Large Hadron Collider is discussed. Prerequisite knowledge and references: - The Standard Model (Lecture by A. Pich) - Beyond the Standard Model (Lecture by E. Kiritsis) Biography- Brief CV: Dr Karl JAKOBS -Studied Physics at the University of Bonn, Germany - Summer student at CERN in 1984 - PhD at the University of Heidelberg, in 1988 Thesis on the UA2-Experiment at the CERN Proton-Antiproton Collider (already Hadron Collider physics at that time) - Fellow and staff position at CERN, UA2 experiment - 1992 - 1996 Max-Planck-Institute for Physics, Munich ALEPH and ATLAS experiments - 1996 - 2003 Prof. of physics at the University of Mainz ALEPH and ATLAS experiments - Since 2000: participation in the D0-Experiment at the Tevatron HR-RFA 07/06 - Since 2003: Prof.
[Show full text]
Antiprotons in the Big Machine
Antiprotons in the big machine Right the beam line which injects 26 GeV antiprotons into the SPS. Centre, the beam fine which sends high energy protons from the SPS towards the West Experimental Area. The main ring is on the left. (Photo CERN 38.4.81) On 7 July a pulse of antiprotons was sent to the CERN Super Proton Synchrotron, accelerated to 270 GeV and (briefly) stored. Two days later the exercise was repeated with greater success and the first evi dence obtained for proton-antipro ton collisions at 540 GeV — by far the highest collision energies ever achieved. Although there is still much to be done before the scheme becomes fully operational, this achievement is a major milestone in the CERN antiproton story. The origins of the project Antiprotons, since they presuma bly have the same properties as protons except for the sign of their electric charge, can be accelerated and stored in the same magnet ring as protons. Thus colliding beam sys tems, like the familiar electron-posi tron machines, are, in principle, fea sible. However until recently it was not possible to produce antiproton tion, the antiprotons emerge with a for colliding beam physics. It in beams of sufficient intensity and wide range of momenta, distinctly volves using electron beams travel density to give sufficient collisions in unsuitable for a magnet system in a ling along with the antiproton beam a reasonable enough time for useful beam transfer line, an accelerator or at the same velocity. The electron physics to be done. a storage ring which is designed to beam, which is much easier to con This situation has changed with handle a well defined particle mo trol, has particles at precisely the the invention of 'beam cooling'.
[Show full text]
The Standard Model 30 Years of Glory
FR0107537 LAX66-128 March 2001 The Standard Model 30 Years of Glory Jacques Lefrangois Laboratoire de l'Accelerateur Lineaire IN2P3-CNRS et Universite de Paris-Sud, BP 34, F-91898 Orsay Cedex Lectures given at the 11th Advanced Study Institute on Techniques and Concepts in High Energy Physics, St. Croix, Virgin Islands, USA, June 15-26, 2000 U.E.R Institut National de de Physique Nucleaire 1'Universite Paris-Sud et de Physique des Particules 5 2/ § 8 B.P. 34 ~ Bailment 200 ~ 91898 ORSAY CEDEX LAL 00-128 March 2001 Doc. Enreg. ie. THE STANDARD MODEL 30 YEARS OF GLORY Jacques Lefrangois Laboratoire de VAccelerateur Lineaire IN2P3-CNRS et Universite PARIS-SUD Centre Scientifique d'Orsay - Bat. 200 - B.P. 34 91898 ORSAY Cedex (France) [email protected] In these three lectures, I will try to give a flavour of the achievements of the past 30 years, which saw the birth, and the detailed confirma- tion of the Standard Model (SM). However I have to start with three disclaimers: B Most of the subject is now history, but I am not an historian, I hope the main core will be exact but I may err on some details. • Being an experimentalist, I will mostly focus on the main exper- imental results, giving, when appropriate, some emphasis to the role of well conceived apparatus. This does not mean that I min- imise the key role of theorist, it only reflects the fact that the same story told by a theorist would correspond to another interesting series of lectures. • Finally, in some cases, I may show a bias coming from the fact that I have seen from closer what has happened in Europe.
[Show full text]
CERN Courier – Digital Edition Welcome to the Digital Edition of the December 2014 Issue of CERN Courier
I NTERNATIONAL J OURNAL OF H IGH -E NERGY P HYSICS CERNCOURIER WELCOME V OLUME 5 4 N UMBER 1 0 D ECEMBER 2 0 1 4 CERN Courier – digital edition Welcome to the digital edition of the December 2014 issue of CERN Courier. As CERN’s 60th-anniversary year comes to an end, CERN Courier gives a voice to some of the organization’s pioneers who are no longer with us. Extracts from audio recordings in CERN’s archives bring to life the spirit of adventure of the early CERN. One of the studies that CERN pioneered was the measurement of the “g-2” parameter of the muon – an experiment that in its latest incarnation is setting up in Fermilab. The year also saw the 50th anniversary of the International Centre for Theoretical Physics in Trieste, and an interview with the centre’s current director reveals interesting similarities and contrasts between the two organizations. The end of the year also offers the traditional seasonal Bookshelf. Happy reading! To sign up to the new-issue alert, please visit: http://cerncourier.com/cws/sign-up. To subscribe to the magazine, the e-mail new-issue alert, please visit: http://cerncourier.com/cws/how-to-subscribe. IceCube: neutrinos and more DETECTORS PEOPLE THE ICTP CUORE: the coldest CERN Council heart in the selects the next AT 50 EDITOR: CHRISTINE SUTTON, CERN known universe director-general An interview with DIGITAL EDITION CREATED BY JESSE KARJALAINEN/IOP PUBLISHING, UK p5 p5 Fernando Quevedo p37 CERNCOURIER www. V OLUME 5 4 N UMBER 1 0 D ECEMBER 2 0 1 4 CERN Courier December 2014 High Vacuum Contents Covering current developments in high-energy physics and related fi elds worldwide CERN Courier is distributed to member-state governments, institutes and laboratories Monitoring and Control afﬁ liated with CERN, and to their personnel.
[Show full text]
The Discovery of the W and Z Particles
June 16, 2015 15:44 60 Years of CERN Experiments and Discoveries – 9.75in x 6.5in b2114-ch06 page 137 The Discovery of the W and Z Particles Luigi Di Lella1 and Carlo Rubbia2 1Physics Department, University of Pisa, 56127 Pisa, Italy [email protected] 2GSSI (Gran Sasso Science Institute), 67100 L’Aquila, Italy [email protected] This article describes the scientific achievements that led to the discovery of the weak intermediate vector bosons, W± and Z, from the original proposal to modify an existing high-energy proton accelerator into a proton–antiproton collider and its implementation at CERN, to the design, construction and operation of the detectors which provided the first evidence for the production and decay of these two fundamental particles. 1. Introduction The first experimental evidence in favour of a unified description of the weak and electromagnetic interactions was obtained in 1973, with the observation of neutrino interactions resulting in final states which could only be explained by assuming that the interaction was mediated by the exchange of a massive, electrically neutral virtual particle.1 Within the framework of the Standard Model, these observations provided a determination of the weak mixing angle, θw, which, despite its large experimental uncertainty, allowed the first quantitative prediction for the mass values of the weak bosons, W± and Z. The numerical values so obtained ranged from 60 to 80 GeV for the W mass, and from 75 to 92 GeV for the Z mass, too large to be accessible by any accelerator in operation at that time.
[Show full text]
Jet Physics in the ATLAS Experiment At
Jet Physics in the ATLAS experiment at LHC Vincenzo Cavasinni on behalf of the ATLAS Collaboration Dipartimento di ﬁsica `E.Fermi' and INFN Pisa, ITALY E-mail: [email protected] Jet physics represents a powerful tool to investigate the properties of quark and gluon interactions. With the advent of LHC, these studies have been possible at an energy never investigated before. In this proceedings we review the main char- acteristics of jets measured by the ATLAS experiment in proton-proton collisions at center-of-mass energies of 7 and 8 TeV. The experimental results are compared with the predictions of the Quantum Chromodymamics, QCD, the standard theory of quark-gluon interactions. A good agreement is found between data and QCD predictions. The jet mesurements provide also a clue in the search for new physics: a few examples of searches for excited quarks and supersymmetric particles are presented. 1 Introduction The proton-proton collider LHC started operations at at center-of-mass energy of 7 TeV in 2010. ATLAS, one of the two multipurpose experiments, has collected an integrated luminosity of ≈ 40pb−1 in 2010 and ≈ 5fb−1 in 2011 . Jet production, consequence of the fragmentation of quarks and gluons in hadronic collisions, is the high-pT process with the highest cross section. Their measurement allows a direct access to the elementary interactions between the constituents of the incoming protons. The emergence of jets in hadron collisions has been proved by the UA2 experiment at ATL-PHYS-PROC-2012-152 30 August 2012 the CERN pp¯ Collider in 1983 [1].
[Show full text]
The Light Gluino Gap Arxiv:1803.01880V1 [Hep-Ph] 5 Mar
Prepared for submission to JHEP The Light Gluino Gap Jared A. Evansa;b and David McKeenc aDepartment of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA bDepartment of Physics, University of Cincinnati, Cincinnati, Ohio 45221, USA cPittsburgh Particle Physics, Astrophysics, and Cosmology Center, Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, USA E-mail: [email protected], [email protected] Abstract: A variety of experimental searches and theoretical efforts have constrained gluinos that undergo an all-hadronic decay with no missing energy, as can arise in R-parity violating or stealth supersymmetry. Although the g~ ! jj decay is robustly excluded, there is gap in current experimental coverage for gluinos with masses between 51–76 GeV that decay into three light-flavor quarks. In this work, we probe this gap with published multi-jet data from the UA2 experiment. Despite setting the strongest current limit on this region, we find that UA2 data is unable to close this gap for g~ ! jjj decays. In addition to this three-jet gap, we note an additional gap for all- hadronic g~ ! n parton decays with n ≥ 4 for light gluinos (51 GeV < mg~ . 300 GeV) not covered by the current search program. arXiv:1803.01880v1 [hep-ph] 5 Mar 2018 Contents 1 Introduction1 2 The UA2 Experiment4 3 Limits on gluinos from multi-jets6 4 Discussion7 1 Introduction The large hadron collider (LHC) has pushed the lower bound on the gluino mass to above 1 TeV for nearly any decay path [1], and for particular decay paths, limits are above 2 TeV; see, e.g., [2].
[Show full text]
Measurements of Single Diffraction at √S = 630
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 9 December, 1997 Measurements of Single Diffraction at √s = 630 GeV; Evidence for a Non-Linear α(t) of the omeron P A. Brandt1, S. Erhana, A. Kuzucu2, D. Lynn3, M. Medinnis4, N. Ozdes2, P.E. Schleinb M.T. Zeyrek5, J.G. Zweizig6 University of California∗, Los Angeles, California 90095, USA. J.B. Cheze, J. Zsembery Centre d’Etudes Nucleaires-Saclay, 91191 Gif-sur-Yvette, France. (UA8 Collaboration) Abstract We report measurements of the inclusive differential cross section for the single- diffractive reactions: p +p ¯ p + X and p +p ¯ X +p ¯ at √s = 630 GeV, i → f i → f in the momentum transfer range, 0.8 < t < 2.0 GeV2 and final state Feynman- − xp > 0.90. Based on the assumption of factorization, several new features of the omeron Flux Factor are determined from simultaneous fits to our UA8 data and P lower energy data from the CHLM collaboration at the CERN-Intersecting Storage Rings. Prominent among these is that the effective omeron Regge trajectory requires ′′ P − a term quadratic in t, with coefficient, α = 0.079 0.012 GeV 4. We also show that ± the data require a omeron-proton cross section that first decreases with increasing P diffractive mass (corresponding to the term in the triple-Regge expansion) PPR and then increases at larger mass (the term), similar to real particle total arXiv:hep-ex/9710004v3 8 Apr 1998 PPP − cross sections. We measure the product, Kσ = 0.72 0.10 mb GeV 2, where K 0 ± is the normalization constant of the omeron Flux Factor in the proton and σ is P 0 the scale constant in the omeron-proton total cross section.
[Show full text]
Intermediate Vector Bosons Production and Identification at the CERN Proton-Antiproton Collider G
europhysics BULLETIN OF THE EUROPEAN PHYSICAL SOCIETY news J.A. Volume 14 Number 10 October 1983 Intermediate Vector Bosons Production and Identification at the CERN Proton-Antiproton Collider G. Brianti and E. Gabathuler, Geneva The recent discoveries1) of the massive boson which is exchanged between them is W± and Z° intermediate vector bosons at called the gluon. This massless particle was CERN are a triumph not only for the discovered4) at the PETRA storage ring in electroweak theory2) which gives a stan DESY in 1978. The fourth force is the gravi dard prescription of how to unify the tational force which holds our Universe electromagnetic and weak interactions, but together. also for the engineers and physicists who The concept of the electroweak interac produced and detected pp collisions in the tion is that both the electromagnetic and SPS collider at CERN. weak forces stem from a single "elec One of the main achievements of ele troweak" force. At very high energies, as mentary particle physics in recent years has for example in the early moments after the been the development of a new class of big bang, the two interactions would be in unified theories which describe the forces distinguishable, i.e. the two forces have of nature that appeared up to that time to the same strength, and therefore the be independent of each other. In the in photon and the three weak bosons (W+, teractions between elementary particles a W and Z°) form the same family of four force is transmitted between two particles particles. The electroweak theory not only by the exchange of another intermediary requires these four particles but specifies particle, which is referred to as a vector that the W± should be very heavy, ~ 80 boson.
[Show full text]
3 Wissenschaftliche Texte Und Populärwissenschaftliche Texte Im Vergleich
Master Das Uebersetzen von populaerwissenschaftlichen Ausstellungstexten : Am Beispiel der Ausstellung "Universum der Teilchen" (CERN) BUCHMANN, Nadine Isabelle Abstract En 2013, l'auteur du présent mémoire a traduit en allemand les textes de l'exposition permanente, interactive et multimédia qui est présentée dans le centre des visiteurs du Centre Européen de Recherche Nucléaire (CERN). Pour ce travail de traduction, le texte source a été approché sous quatre points de vue : l'hypertexte, la pédagogie muséale, la vulgarisation scientifique et la terminologie. Après la présentation de quelques réflexions théoriques en rapport avec ces quatre perspectives, le mémoire décrit comment elles ont influencé la stratégie de traduction et détaille quels changements ont été nécessaires pour que le texte cible soit tout aussi lisible, compréhensible et stimulant pour les visiteurs germanophones que le texte de départ pour les visiteurs maitrisant l'anglais. Les résultats de ces réflexions sont ensuite résumés sous une forme d'un guide à l'intention de traducteurs procédant à une traduction de textes d'expositions de vulgarisations scientifique. Reference BUCHMANN, Nadine Isabelle. Das Uebersetzen von populaerwissenschaftlichen Ausstellungstexten : Am Beispiel der Ausstellung "Universum der Teilchen" (CERN). Master : Univ. Genève, 2014 Available at: http://archive-ouverte.unige.ch/unige:40321 Disclaimer: layout of this document may differ from the published version. 1 / 1 Nadine Buchmann Das Übersetzen von populärwissenschaftlichen Ausstellungstexten Am Beispiel der Ausstellung „Universum der Teilchen“ (CERN) Directrice de mémoire: Gunhilt Perrin Juré: Detlef Kotte Jurée: Donatella Pulitano Mémoire présenté à la Faculté de traduction et d’interprétation (Département de traduction, Unité d’allemand) pour l’obtention de la Maîtrise universitaire en traduction, mention traduction specialisée 2 INHALTSVERZEICHNIS 0 Einleitung ...............................................................................................................
[Show full text]