During 1980, the research program in experimental high energy physics at The Rockefeller University has made substantial contributions to the understanding of both strong and weak interactions. The principal Laboratories which have been utilized in this work are the 500 GeV accelerator at Fermilab and the Intersecting Storage Rings facility at CERN. The latter is a facility unique in the world which provides the highest available energies for proton-proton collisions. The results of the individual experimental projects obtained during 1980 are described in some detail.
This is the final report of a program of research on ``Experimental Studies of Elementary Particle Interactions at High Energies'' of the High Energy Physics (HEP) group of The Rockefeller University. The research was carried out using the Collider Detector at Fermilab (CDF) and the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) at CERN. Three faculty members, two research associates, and two postdoctoral associates participated in this project. At CDF, we studied proton-antiproton collisions at an energy of 1.96 TeV. We focused on diffractive interactions, in which the colliding antiproton loses a small fraction of its momentum, typically less than 1%, while the proton is excited into a high mass state retaining its quantum numbers. The study of such collisions provides insight into the nature of the diffractive exchange, conventionally referred to as Pomeron exchange. In studies of W and Z production, we found results that point to a QCD-based interpretation of the diffractive exchange, as predicted in a data-driven phenomenology developed within the Rockefeller HEP group. At CMS, we worked on diffraction, supersymmetry (SUSY), dark matter, large extra dimensions, and statistical applications to data analysis projects. In diffraction, we extended our CDF studies to higher energies working on two fronts: measurement of the single/double diffraction and of the rapidity gap cross sections at 7 TeV, and development of a simulation of diffractive processes along the lines of our successful model used at CDF. Working with the PYTHIA8 Monte Carlo simulation authors, we implemented our model as a PYTHIA8-MBR option in PYTHIA8 and used it in our data analysis. Preliminary results indicate good agreement. We searched for SUSY by measuring parameters in the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM) and found results which, combined with other experimental constraints and theoretical considerations, indicate that the CMSSM is not a viable model. Expressing our results in terms of simple topologies, we exclude squark masses below 0.75 TeV and gluino masses below 1.1 TeV. Astrophysical measurements suggest that about 80% of the matter density of the Universe is non-luminous. One of the theories on dark matter attributes it to Weakly Interacting Massive Particles (WIMPs). We searched for WIMPs in 7 TeV and 8 TeV collisions at CMS and set limits on WIMP production rates, which are competitive and complementary to those of direct detection experiments. Searching for monojets (events with only one jet), which in a popular model could be produced by a jet paired by a gravitino that escapes into extra dimensions, we significantly improved the previously set limit. Our results have been used to set limits on Higgs decay to invisible particles and on production of top squarks in compressed SUSY scenarios. Statistics. We computed Bayesian reference priors for several types of measurement and used them in the analysis of CMS data; investigated the applicability of bootstrap methods to HEP measurements; studied several issues associated with simple-versus-simple hypothesis testing and applied the resulting methods to the measurement of some properties of the top quark and Higgs boson.
This is a report of the research activities of the Experimental High Energy Physics group of The Rockefeller University. As this is an annual progress report, the emphasis is on last year's research activities. However, since it is the last of a series of 5 such reports to be submitted to the DOE under the present 5 year contract, an effort has been made to provide comprehensive coverage of the research activities of the group throughout the contract period. In the past 5 years, the research program encompassed three major areas: the UA-6 experiment at CERN, the CDF experiment at Fermilab, and several SSC projects. The UA-6 experiment studies direct-[gamma] and J/[Psi] production in pp and {bar p}p interactions at √s = 22.5 GeV.4. In the CDFF experiment the authors have concentrated in the area of small angle physics, where the objective has been to measure the elastic, diffractive and total cross sections, and to provide an absolute calibration of the machine luminosity. The SSC research projects related to two experiments: The Solenoidal Detector Collaboration and the ''low p{sub T} physics'' experiment.
The book provides theoretical and phenomenological insights on the structure of matter, presenting concepts and features of elementary particle physics and fundamental aspects of nuclear physics. Starting with the basics (nomenclature, classification, acceleration techniques, detection of elementary particles), the properties of fundamental interactions (electromagnetic, weak and strong) are introduced with a mathematical formalism suited to undergraduate students. Some experimental results (the discovery of neutral currents and of the W± and Z0 bosons; the quark structure observed using deep inelastic scattering experiments) show the necessity of an evolution of the formalism. This motivates a more detailed description of the weak and strong interactions, of the Standard Model of the microcosm with its experimental tests, and of the Higgs mechanism. The open problems in the Standard Model of the microcosm and macrocosm are presented at the end of the book.
Part of the Physics in a New Era series of assessments of the various branches of the field, Elementary-Particle Physics reviews progress in the field over the past 10 years and recommends actions needed to address the key questions that remain unanswered. It explains in simple terms the present picture of how matter is constructed. As physicists have probed ever deeper into the structure of matter, they have begun to explore one of the most fundamental questions that one can ask about the universe: What gives matter its mass? A new international accelerator to be built at the European laboratory CERN will begin to explore some of the mechanisms proposed to give matter its heft. The committee recommends full U.S. participation in this project as well as various other experiments and studies to be carried out now and in the longer term.
The Summer Institute on High Energy Physics was the second of this kind organized at Louvain. Four years ago we had already decided to organize a Summer Institute. The first one was con ceived in 1970, at Kiev, by D. Speiser, J. Weyers, and G. Zweig, and thanks to a NATO grant took place from August 20th to Septem ber 15th 1971, at Louvain in the Groot Begijnhof. All lectures were directed toward one subject: duality. The lecturers were R. Brout (ULB - Bruxelles), D. Fairlie (University of Durham), F. Gilman (SLAC - Stanford), D. Horn (University of Tel Aviv), J. Mandula (Caltech - Pasadena), C. Michael (CERN - Geneva), J. Rosner (University of Minnesota), C. Schmidt (CERN - Geneva), J. Veneziano (The Weizmann Institute), J. Weyers (UCL - Louvain and CERN - Geneva), and G. Zweig (Caltech - Pasadena). The direc tion was in the hands of F. Cerulus (KUL - Louvain), R. Rodenberg (Technische Hochschule, Aachen), D. Speiser (UCL - Louvain), and J. Weyers (CERN - Geneva). Unfortunately it was not possible to publish the lecture notes for that Institute. The second Summer Institute on Elementary Particle Physics took place from August 12th to August 25th 1973, again in Louvain. It was initiated in Chicago, in 1972, by F. Halzen (University of Wisconsin) and J. Weyers (UCL - Louvain and CERN - Geneva). Lecturers included R. Carlitz (University of Chicago), F. Gilman (SLAC - Stanford), F. Halzen (University of Wisconsin), D.
Part of the Physics in a New Era series of assessments of the various branches of the field, Elementary-Particle Physics reviews progress in the field over the past 10 years and recommends actions needed to address the key questions that remain unanswered. It explains in simple terms the present picture of how matter is constructed. As physicists have probed ever deeper into the structure of matter, they have begun to explore one of the most fundamental questions that one can ask about the universe: What gives matter its mass? A new international accelerator to be built at the European laboratory CERN will begin to explore some of the mechanisms proposed to give matter its heft. The committee recommends full U.S. participation in this project as well as various other experiments and studies to be carried out now and in the longer term.
This textbook is a unique treatise on the present status of particle physics summarised for physics students at an introductory level: it provides insights into the essential experimental and theoretical techniques needed to start research at modern high energy accelerators such as the Large Hadron Collider at CERN. The first three parts of the book discuss the experimental and phenomenological aspects at a level suitable for MSc students, but BSc students interested in particle physics will also find useful information there. The fourth part is oriented to advanced MSc or PhD students to make them acquainted with the precise formulation of the standard model of particle interactions, as well as with the mathematical background needed for the correct interpretation of the experimental results. In this two-step approach, the book offers a gradually deepening understanding of particle physics, building up the standard model and providing an overview of its verification, together with the necessary theoretical and experimental techniques. Using the example of the simplest present-day experiments, it is explained how one can obtain experimental results and theoretical estimations for measurable quantities from clear basic principles. The sources of uncertainties and the methods of improving precision are also discussed.
