Medieninformation Kommunikation und Medien
Haller-Dintelmann, Robert
Schneider und Lukas Quurck für ihre Idee eines kinetischen Energiespeichers aus. Mit diesem kann Strom
Relationen-Algebra und Implementierungskonzepte
GÃ¼ting, Ralf Hartmut
Relationen-Algebra und Persistenz Implementierungskonzepte und Anforderungen an Attributdatentypen und Operationen der RelationAlgebra DBArrays und FLOBs Attributsdatentypen Tupel ReferenzzÃ¤hler: filter Signature: ((stream x) (map x bool)) -> (stream x) Syntax: _ filter [ fun ] Meaning: Only tuples
Biologie, Chemie und Verfahrenstechnik
Schmitt, Peter H.
Technologie (MT) Helmholtz-Programm Von Materie zu Materialien und Leben (MML) Helmholtz-Programm Erneuerbare Energien (EE) Archiv (ARCHIV) KIT-Bibliothek (BIB) Forschungsförderung (FOR) Forschung und Information
Alignmentkorrekturen und Fusion von Dokumentaufnahmen
Block, Marco
Alignmentkorrekturen und Fusion von Dokumentaufnahmen Am Fachbereich Mathematik und Informatik . . . . . . . . . . . . . . . . . . . . . . . . 18 Exposure Blending . . . . . . . . . . . . . . . . . . . . . . 19 Exposure Fusion . . . . . . . . . . . . . . . . . . . . . . 23 Varianz . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Energy of Image Gradient
Departement Maschinenbau und Verfahrenstechnik
Daraio, Chiara
Bioengineering von J. Snedecker und S. Panke zu belegen. Wählbare Fächer LE-Nr. Dozent Spra- che ECTS HS ECTS FS
Wissenschaftliches Netzwerk Sozialfrsorge und Gesundheit in Ost-und Sdosteuropa
Schubart, Christoph
, Forschungsassistentin Universität Wien / Österreich und Oberassistentin Andrássy Universität Budapest / Ungarn · Dr
Der Alte und der Neue Sden Axel Borsdorf DER ALTE UND DER NEUE SDEN.
Borsdorf, Axel
Dauergrünland und Futterpflanzenanbau gekennzeichnet. Die Bodennutzung paßt sich damit den klimatischen und
Institut fr Werkzeugmaschinen und Fabrikbetrieb
Berlin,Technische Universität
Energiemanage- mentsystem auf Fabrikebene. Für die Einführung und den Betrieb dieser Systeme soll ein
Musik mit Bremstrommel und Mnzen im Klavier Gttingen. Pfeifgerusche, das
Wardetzky, Max
(,,Heul doch") und James Brown, Björn hört Apollo 3, und Jasmin und Svenja haben ein Faible für Lady Gaga. bar Lafee und Lady Gaga Svenja Björn Jasmin G
Experimentsteuerung Hardware und Software fr PC und Peripherie
Osnabrück, Universität
Experimentsteuerung Hardware und Software für PC und Peripherie Klaus Betzler Universität Osnabrück Sommersemester 1990 Inhaltsverzeichnis 1 PC-Hardware 1 1.1 Die CPU Intel 8086.2.2 Ein/Ausgabe-Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Software
Heimatblatt Stadt und Land Studenten sind Klimawandel
Damm, Werner
- nisterium für Bildung und For- schung gefördert und beschäf- tigt sich mit der Landnutzung in Küstenräumen Bildung und For- schung (BMBF) geförderte Forschungsprojekt ,,COM- TESS", das eine nachhaltige Landnutzung
BERATER UND UNTERSCHRIFTSBEFUGTE ANERKENNUNG (BZGL. PRAKTIKUMSVEREINBARUNG)
Schüler, Axel
-Siegmund Institut für Psychologie Prof. Dr. Evelin Witruk CHEMIE UND MINERALOGIE Prof. Dr. Reinhard Denecke denecke
Technische Universitt Mnchen Daten und Fakten 2013
Kuehnlenz, Kolja
· Physik Freising · Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt TUM Standorte
Paderborn, Universität
Universität Paderborn Leistungselektronik und Elektrische Antriebstechnik, Prof. Dr. Joachim Böcker -1- Mechatronik und elektrische Antriebe A Beispiele für mechatronische Systeme #12;Universität Paderborn Leistungselektronik und Elektrische Antriebstechnik, Prof. Dr. Joachim Böcker -2- Nicht
Knuth, T
2000-01-01T23:59:59.000Z
Auslegung, Entwicklung und Inbetriebnahme eines longitudinalen und transversalen Feedbacksystems zur Dämpfung gekoppelter Teilchenpaket-Instabilitäten im BESSY-II-Speicherring
Putty und clay Funktionen in Produktion und Finanzen Eine Einfhrung in die Makro-konophysik
Mimkes, Jürgen
Putty und clay Funktionen in Produktion und Finanzen Eine Einführung in die Makro Funktionen als putty oder clay. Putty bedeutet Kitt, der erst weich ist und dann fest wird. Eine putty Jahresende (ex post) ist es fixiert. Clay bedeutet Ton. Eine (gebrannte) Tonschale ist anfangs fest und auch
Villafranca Die Kabinete und die Revolutionen.
Prodinger, Helmut
bucklige Bursche, und lobte mich, daß ich Soldat werden wollte. Er sagte, den Soldaten allein gehöre die
Erich W. Varnes
2008-10-20T23:59:59.000Z
A review is presented of the current experimental status of the top quark sector of the standard model. The measurements summarized include searches for electroweak single top production, the latest results on the ttbar production cross section, and searches for new physics in top quark production and decay. In addition, the recent measurement of the top quark mass to a precision of 0.7% is highlighted
Christian Schwanenberger
2010-04-28T23:59:59.000Z
Highlights of top quark physics presented at the 2009 Europhysics Conference on High Energy Physics from 16-22 July 2009 in Krakow, Poland, are reviewed.
Eric Laenen
2008-09-18T23:59:59.000Z
I review how the top quark is embedded in the Standard Model and some its proposed extensions, and how it manifests itself in various hadron collider signals.
Quantum chromodynamics quark benzene
Jialun Ping; Chengrong Deng; Fan Wang; T. Goldman
2007-11-28T23:59:59.000Z
A six-quark state with the benzene-like structure is proposed and studied based on color string model. The calculation with the quadratic confinement show that such structure has the lowest energy among the various hidden color six-quark structures proposed so far. Its possible effect on $NN$ scattering is discussed.
Quark Number Susceptibility with Finite Quark Mass in Holographic QCD
Kyung-il Kim; Youngman Kim; Shingo Takeuchi; Takuya Tsukioka
2011-10-31T23:59:59.000Z
We study the effect of a finite quark mass on the quark number susceptibility in the framework of holographic QCD. We work in a bottom-up model with a deformed AdS black hole and D3/D7 model to calculate the quark number susceptibility at finite temperature with/without a finite quark chemical potential. As expected the finite quark mass suppresses the quark number susceptibility. We find that at high temperatures $T\\ge 600$ MeV the quark number susceptibility of light quarks and heavy quarks are almost equal in the bottom-up model. This indicates that the heavy quark like charm contribution to thermodynamics of a QCD-like system may start to become significant at temperatures $T\\sim 600$ MeV. In D3/D7 model, we focus on the competition between the quark chemical potential, which enhances the quark number susceptibility, and the quark mass that suppresses the susceptibility. We observe that depending on the relative values of the quark mass and the quark chemical potential, the quark number susceptibility shows a diverging or converging behavior. We also calculate the chiral susceptibility in D3/D7 model to support the observation made with the quark number susceptibility.
Peters, Yvonne
2011-12-01T23:59:59.000Z
Since its discovery in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron collider, the top quark has undergone intensive studies. Besides the Tevatron experiments, with the start of the LHC in 2010 a top quark factory started its operation. It is now possible to measure top quark properties simultaneously at four different experiments, namely ATLAS and CMS at LHC and CDF and D0 at Tevatron. Having collected thousands of top quarks each, several top quark properties have been measured precisely, while others are being measured for the first time. In this article, recent measurements of top quark properties from ATLAS, CDF, CMS and D0 are presented, using up to 5.4 fb{sup -1} of integrated luminosity at the Tevatron and 1.1 fb{sup -1} at the LHC. In particular, measurements of the top quark mass, mass difference, foward backward charge asymmetry, t{bar t} spin correlations, the ratio of branching fractions, W helicity, anomalous couplings, color flow and the search for flavor changing neutral currents are discussed.
Yvonne Peters; for the Atlas Collaboration; CDF Collaboration; CMS Collaboration; D0 Collaboration
2011-12-02T23:59:59.000Z
Since its discovery in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron collider, the top quark has undergone intensive studies. Besides the Tevatron experiments, with the start of the LHC in 2010 a top quark factory started its operation. It is now possible to measure top quark properties simultaneously at four different experiments, namely ATLAS and CMS at LHC and CDF and D0 at Tevatron. Having collected thousands of top quarks each, several top quark properties have been measured precisely, while others are being measured for the first time. In this article, recent measurements of top quark properties from ATLAS, CDF, CMS and D0 are presented, using up to 5.4 fb-1 of integrated luminosity at the Tevatron and 1.1 fb^-1 at the LHC. In particular, measurements of the top quark mass, mass difference, forward backward charge asymmetry, tt - spin correlations, the ratio of branching fractions, W helicity, anomalous couplings, color flow and the search for flavor changing neutral currents are discussed.
RWTH Publications: Publizieren und Eintragen | Edmund Wollgarten | Universittsbibliothek
Rheinisch-Westfälische Technische Hochschule Aachen (RWTH)
RWTH Publications: Publizieren und Eintragen | Edmund Wollgarten | Universitätsbibliothek RWTH Publications Publizieren und Eintragen #12;RWTH Publications: Publizieren und Eintragen | Edmund Wollgarten | Universitätsbibliothek Importieren oder eintragen? RWTH Publications bietet Ihnen eine bequeme Eingabe per Import, wenn
BOOK REVIEW: Fräuleins und GIs, by Annette Brauerhoch
Layne, Priscilla D
2007-01-01T23:59:59.000Z
Brauerhoch. Fräuleins und GIs. Frankfurt am Main und Basel:Identity. ” 1 In Fräuleins und GIs, Brauerhoch wishes toin the topic of Fräuleins and GIs in the immediate postwar
Institut fr Energie-und Automatisierungstechnik FG Elektronische Mess-und Diagnosetechnik
Wichmann, Felix
,,Thermoeletrische Generatoren 2020" (TEG 2020) wird die Entwicklung modularer, leistungsstarker und flexibel einsetzbarer thermoelektrischer Genera- toren (TEG) zur elektrischen Rückgewinnung in Verbrennungsmaschinen und -anlagen angestrebt. Bei TEG handelt es sich um die direkte Wandlung von thermischer in elektrischer
Institut fr Energie-und Automatisierungstechnik FG Elektronische Mess-und Diagnosetechnik
Wichmann, Felix
- Foschungsprojekt ,,Thermoeletrische Generatoren 2020" (TEG 2020) wird die Entwicklung modularer, leistungsstarker und flexibel einsetzbarer thermoelektrischer Genera- toren (TEG) zur elektrischen Rückgewinnung in Verbrennungsmaschinen und -anlagen angestrebt. Bei TEG handelt es sich um die direkte Wandlung von thermischer
Efe Yazgan; for the CMS Collaboration
2014-09-12T23:59:59.000Z
Measurements involving top quarks provide important tests of QCD. A selected set of top quark measurements in CMS including the strong coupling constant, top quark pole mass, constraints on parton distribution functions, top quark pair differential cross sections, ttbar+0 and >0 jet events, top quark mass studied using various kinematic variables in different phase-space regions, and alternative top quark mass measurements is presented. The evolution of expected uncertainties in future LHC runs for the standard and alternative top quark mass measurements is also presented.
Heidi Schellman and Ann Heinson
2009-03-12T23:59:59.000Z
Fermilab researchers Heidi Schellman and Ann Heinson take a whimsical look at the recent announcement of the discovery of the single top quark, by Fermilab's CDF and DZero experiments.
Tony M. Liss
2012-12-03T23:59:59.000Z
I review the latest results on properties of the top quark from the Tevatron and the LHC, including results measured in $t\\bar{t}$ and single-top events on the mass, width, couplings, and spin correlations.
Qi Liu; Norman H. Christ; Chulwoo Jung
2012-06-01T23:59:59.000Z
We present a systematic study of the effectiveness of light quark mass reweighting. This method allows a single lattice QCD ensemble, generated with a specific value of the dynamical light quark mass, to be used to determine results for other, nearby light dynamical quark masses. We study two gauge field ensembles generated with 2+1 flavors of dynamical domain wall fermions with light quark masses m_l=0.02 (m_\\pi=620 MeV) and m_l=0.01 (m_\\pi=420 MeV). We reweight each ensemble to determine results which could be computed directly from the other and check the consistency of the reweighted results with the direct results. The large difference between the 0.02 and 0.01 light quark masses suggests that this is an aggressive application of reweighting as can be seen from fluctuations in the magnitude of the reweighting factor by four orders of magnitude. Never-the-less, a comparison of the reweighed topological charge, average plaquette, residual mass, pion mass, pion decay constant, and scalar correlator between these two ensembles shows agreement well described by the statistical errors. The issues of the effective number of configurations and finite sample size bias are discussed. An examination of the topological charge distribution implies that it is more favorable to reweight from heavier mass to lighter quark mass.
Tobias Bolch Rezenter Gletscherschwund und Klimawandel
Bolch, Tobias
Tobias Bolch Rezenter Gletscherschwund und Klimawandel im nördlichen Tien Shan (Kasachstan/Kyrgyzstan). Sie befinden sich im kontinentalen Bereich des südlichen Ka- sachstans an der Grenze zu Kyrgyzstan
Physics with boosted top quarks
Elin Bergeaas Kuutmann
2014-08-29T23:59:59.000Z
The production at the LHC of boosted top quarks (top quarks with a transverse momentum that greatly exceeds their rest mass) is a promising process to search for phenomena beyond the Standard Model. In this contribution several examples are discussed of new techniques to reconstruct and identify (tag) the collimated decay topology of the boosted hadronic decays of top quarks. Boosted top reconstruction techniques have been utilized in searches for new physical phenomena. An overview is given of searches by ATLAS, CDF and CMS for heavy new particles decaying into a top and an anti-top quark, vector-like quarks and supersymmetric partners to the top quark.
Nr. 012 // 2014 // 24. Januar 2014 Klima-und Umweltwandel im Sahel
Schmidt, Matthias
Maßstabsebene darstellt und welche Zusammenhänge zwischen Klima, Landnutzung und Vegetations- veränderung mögliche Konsequenzen von Umweltwandel, Klima und Landnutzung, werden sogenannte Umweltflüchtlinge
1 Veranderungen der Ener-gieerzeugung und -verteilung
Appelrath, Hans-Jürgen
Energien wie Windkraft-, Solar, Wasser, Biogas- und Geothermieanlagen. Zum anderen wurde nicht zuletzt
Forschungsstark, praxisnah und gesellschaftlich aktiv Die engagierten Hochschulen
Reyle, Uwe
Selbstfahrende Koffer und Fahrräder mit Energiespeicher Die TU Darmstadt fördert interdisziplinäres Lernen 28 Ein
Forschungsstark, praxisnah und gesellschaftlich aktiv Die engagierten Hochschulen
Heermann, Dieter W.
Fächergrenzen ein 22 Selbstfahrende Koffer und Fahrräder mit Energiespeicher Die TU Darmstadt fördert
Messdatenerfassung und Kommunikation im MICRO GRID eines industriellen Produktionsstandortes
Paderborn, Universität
Energiespeicher und eine ,,POWER TO GAS" -Anlage kompensiert werden. Die intelligente Koordination von Erzeugungs
Friedemann Mattern / Marc Langheinrich Eingebettete, vernetzte und autonom
autarke, aber drahtlos miteinander kommunizierende Computer in Dinge und Le- bensrÃ¤ume integriert werden
Particle-in-Cell Simulation von Elektronenstrahlen und Laserpulsen in
Kull, Hans-Jörg
, · meiner Freundin Evelin für das Korrekturlesen, · und ganz besonders meinen Eltern für die Ermöglichung
Presseinformation Presse und Kommunikation Leiterin: Dr. Elisabeth Zuber-Knost
Schmitt, Peter H.
Programme Erneuerbare Energien und Rationelle Energieumwandlung erhalten durch die Zusammenführung mit den
Schizophrenien und andere psychotische Strungen (1) Prof. Dr. Marc Ziegenbein
Manstein, Dietmar J.
): Kognitiv-behaviorale Therapie bei Anorexia Nervosa und Bulimia Nervosa PD Dr. Burkard Jäger Gruppenraum
Paul B. Mackenzie
1992-12-14T23:59:59.000Z
Lattice calculations of heavy quark systems provide very good measures of the lattice spacing, a key element in recent determinations of the strong coupling constant using lattice methods. They also provide excellent testing grounds for lattice methods in general. I review recent phenomenological and technical developments in this field.
20 Kombination von C++ und Java 20-1(368) 20 Kombination von C++ und Java
Arndt, Holger
20 Kombination von C++ und Java 20-1(368) 20 Kombination von C++ und Java Inhalt 20.1 Java Native Interface (JNI) 20.1.1 C++-Funktionen aus Java aufrufen 20.1.2 Java-Funktionen aus C++ aufrufen 20.2 gcj und das Compiled Native Interface (CNI) 20.2.1 C++-Funktionen aus Java aufrufen 20.2.2 Java-Funktionen aus
20 Kombination von C++ und Java 20-1 20 Kombination von C++ und Java
Arndt, Holger
20 Kombination von C++ und Java 20-1 20 Kombination von C++ und Java Inhalt 20.1 Java Native Interface (JNI) 20.1.1 C++-Funktionen aus Java aufrufen 20.1.2 Java-Funktionen aus C++ aufrufen 20.2 gcj und das Cygnus Native Interface (CNI) 20.2.1 C++-Funktionen aus Java aufrufen 20.2.2 Java-Funktionen aus C
Institut fr Energie-und Automatisierungstechnik FG Elektronische Mess-und Diagnosetechnik
Wichmann, Felix
BMBF-Forschungsprojektes ,,Thermoelektrische Generatoren 2020" (TEG 2020) unter Berücksichti- gung Anbindung zwischen einzelnen TEG und dem Bordnetz werden DC/DC-Wandler eingesetzt, welche jeweils statisch
The Multimedia Project Quarked!
Bean, Alice
2011-01-01T23:59:59.000Z
Can exposure to fundamental ideas about the nature of matter help motivate children in math and science and support the development of their understanding of these ideas later? Physicists, designers, and museum educators at the University of Kansas created the Quarked!(tm) Adventures in the subatomic Universe project to provide an opportunity for youth to explore the subatomic world in a fun and user friendly way. The project components include a website (located at http://www.quarked.org) and hands-on education programs. These are described and assessment results are presented. Questions addressed include the following. Can you engage elementary and middle school aged children with concepts related to particle physics? Can young children make sense of something they can't directly see? Do teachers think the material is relevant to their students?
Santopinto, E
2015-01-01T23:59:59.000Z
In this contribution, we briefly discuss the results for charmonium and bottomonium spectra with self-energy corrections in the unquenched quark model, due to the coupling to the meson-meson continuum. The UQM formalism can be extended to include also the effects of hybrid mesons, i.e. hybrid loops. Finally, we discuss the results of a calculation of hybrid mesons spectrum in Coulomb Gauge QCD.
E. Santopinto; J. Ferretti
2015-03-10T23:59:59.000Z
In this contribution, we briefly discuss the results for charmonium and bottomonium spectra with self-energy corrections in the unquenched quark model, due to the coupling to the meson-meson continuum. The UQM formalism can be extended to include also the effects of hybrid mesons, i.e. hybrid loops. Finally, we discuss the results of a calculation of hybrid mesons spectrum in Coulomb Gauge QCD.
Top quark pair production and top quark properties at CDF
Chang-Seong Moon
2014-11-01T23:59:59.000Z
We present the most recent measurements of top quark pairs production and top quark properties in proton-antiproton collisions with center-of-mass energy of 1.96 TeV using CDF II detector at the Tevatron. The combination of top pair production cross section measurements and the direct measurement of top quark width are reported. The test of Standard Model predictions for top quark decaying into $b$-quarks, performed by measuring the ratio $R$ between the top quark branching fraction to $b$-quark and the branching fraction to any type of down quark is shown. The extraction of the CKM matrix element $|V_{tb}|$ from the ratio $R$ is discussed. We also present the latest measurements on the forward-backward asymmetry ($A_{FB}$) in top anti-top quark production. With the full CDF Run II data set, the measurements are performed in top anti-top decaying to final states that contain one or two charged leptons (electrons or muons). In addition, we combine the results of the leptonic forward-backward asymmetry in $t\\bar t$ system between the two final states. All the results show deviations from the next-to-leading order (NLO) standard model (SM) calculation.
Boehringer, Hans
LMU SS09: Galaxien und Galaxienhaufen im Universum The integral constraint (I) 8 (r)measured = (r)true LMU SS09: Galaxien und Galaxienhaufen im Universum Agenda · The correlation function Measurement function and the power spectrum of the density fluctuations · Higher order statistics · Baryonic acoustic
Simulations with dynamical HISQ quarks
A. Bazavov; C. Bernard; C. DeTar; W. Freeman; Steven Gottlieb; U. M. Heller; J. E. Hetrick; J. Laiho; L. Levkova; M. Oktay; J. Osborn; R. L. Sugar; D. Toussaint; R. S. Van de Water
2010-12-06T23:59:59.000Z
We report on the status of a program of generating and using configurations with four flavors of dynamical quarks, using the HISQ action. We study the lattice spacing dependence of physical quantities in these simulations, using runs at several lattice spacings, but with the light quark mass held fixed at two tenths of the strange quark mass. We find that the lattice artifacts in the HISQ simulations are much smaller than those in the asqtad simulations at the same lattice spacings and quark masses. We also discuss methods for setting the scale, or assigning a lattice spacing to ensembles run at unphysical parameters.
Karolos Potamianos
2011-12-01T23:59:59.000Z
We present the recent results of top-quark physics using up to 6 fb$^{-1}$ of $p\\bar{p}$ collisions analyzed by the CDF collaboration. The large number of top quark events analyzed, of the order of several thousands, allows stringent checks of the standard model predictions. Also, the top quark is widely believed to be a window to new physics. We present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.
Potamianos, Karolos
2011-12-01T23:59:59.000Z
We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions analyzed by the CDF collaboration. The large number of top quark events analyzed, of the order of several thousands, allows stringent checks of the standard model predictions. Also, the top quark is widely believed to be a window to new physics. We present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.
Organigramm 12 Organe der Stiftung und weitere Gremien 13
Nationale und Internationale Zusammenarbeit 19 5 #12;6 #12;Vorwort Vorwort Das Deutsche Elektronen-Synchrotron sich BESSY, das Max-Born-Institut Berlin und die TU-Darmstadt an PITZ. Vom 15.01. bis zum 17
Bachelor-, Master-und Doktorandenseminar des Instituts fr Informatik
Zachmann, Gabriel
wird. Die Wahl fällt dabei auf die Integration von CMMI-DEV und ITIL bzw. ITIL Service Design. Zur Schnittstellenbereiche vorgestellt, an denen sich Prozessgebiete von CMMI-DEV und ITIL Service Design berühren. Daraufhin
Particle-in-Cell (PIC) Simulation Plasmawellenerzeugung und Elektronenbeschleunigung
Kull, Hans-Jörg
Einleitung Particle-in-Cell (PIC) Simulation Plasmawellenerzeugung und Elektronenbeschleunigung;Einleitung Particle-in-Cell (PIC) Simulation Plasmawellenerzeugung und Elektronenbeschleunigung Particle-in-Cell (PIC) Simulation Konzeption des PIC Algorithmus Der verwendete Algorithmus Test
Cold quark matter in compact stars
Franzon, B.; Fogaca, D. A.; Navarra, F. S. [Instituto de Fisica, Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-090 Sao Paulo, SP (Brazil); Horvath, J. E. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao, 1226, 05508-090, Sao Paulo, SP (Brazil)
2013-03-25T23:59:59.000Z
We used an equation of state for the cold quark matter to the study of properties of quark stars. We also discuss the absolute stability of quark matter and compute the mass-radius relation for self-bound stars.
Heavy Quark production at HERA and Heavy Quark contributions
Detlef Bartsch, University of Bonn on behalf of the ZEUS and H1 Collaborations Â· Introduction Â· Heavy 1500 0 100 200 300 400 electrons positrons low E HERA-1 HERA-2 Detlef Bartsch Heavy Quark production Detlef Bartsch Heavy Quark production at HERA, Feb. 23rd 2008 3 #12;pQCD approximations Massive scheme
Universitat Stuttgart -Institut fur Wasser-und Umweltsystemmodellierung
Cirpka, Olaf Arie
Energiequelle und Fracking h¨alt an den knapper werdenden, herk¨ommlichen, fossilen Energietr¨agern fest. Alle
Aspekte der Paranoia in utopischer Literatur und Film
Schuetze, Andre
2013-01-01T23:59:59.000Z
aus fast unsichtbar, ein Soldat. Man konnte zwar mit demund Hofpage, Opfer und Soldat im Dreißigjährigen Krieg,
Charm Quark Energy Loss in QCD Matter
W. C. Xiang; H. T. Ding; D. C. Zhou; D. Rohrich
2005-07-13T23:59:59.000Z
The energy loss of heavy quarks in a quark-gluon plasma of finite size is studied within the light-cone integral approach. A simple analytical formulation of the radiative energy loss of heavy quarks is derived. This provides a convenient way to quantitatively estimate the quark energy loss. Our results show that if the energy of a heavy quark is much larger than its mass, the radiative energy loss approaches the radiative energy loss of light quarks.
Sudan und Sd-Sudan. Vom Konflikt zur Kooperation?
Koenig, Friederike - Fachbereich 2 Biologie
Sudan und Süd-Sudan. Vom Konflikt zur Kooperation? Professor Dr. Karl Wohlmuth (Fachbereich aktuellen Konflikte zwischen dem Sudan und dem Süd-Sudan haben, wie die Konflikte innerhalb der beiden internationalen Grenze zwischen Sudan und Süd-Sudan mobilisiert werden können. Schon vor der Unabhängigkeit des
L. Cerrito
2004-07-16T23:59:59.000Z
Preliminary results on the measurement of the top quark mass at the Tevatron Collider are presented. In the dilepton decay channel, the CDF Collaboration measures m{sub t} = 175.0{sub -16.9}{sup +17.4}(stat.){+-}8.4(syst.) GeV/c{sup 2}, using a sample of {approx} 126 pb{sup -1} of proton-antiproton collision data at {radical}s = 1.96 TeV (Run II). In the lepton plus jets channel, the CDF Collaboration measures 177.5{sub -9.4}{sup +12.7}(stat.) {+-} 7.1(syst.) GeV/c{sup 2}, using a sample of {approx} 102 pb{sup -1} at {radical}s = 1.96 TeV. The D0 Collaboration has newly applied a likelihood technique to improve the analysis of {approx} 125 pb{sup -1} of proton-antiproton collisions at {radical}s = 1.8 TeV (Run I), with the result: m{sub t} = 180.1 {+-} 3.6(stat.) {+-}3.9(syst.) GeV/c{sup 2}. The latter is combined with all the measurements based on the data collected in Run I to yield the most recent and comprehensive experimental determination of the top quark mass: m{sub t} = 178.0 {+-} 2.7(stat.) {+-} 3.3(syst.) GeV/c{sup 2}.
Quantum Collapse in Quark Stars?
Perez Martinez, A.; Perez Rojas, H. [ICIMAF, Calle E esq 15 No. 309 Vedado (Cuba); Mosquera Cuesta, H. J. [Centro Brasileiro de Pesquisas Fisicas, Laboratorio de Cosmologia e Fisica Experimental de Altas Energias, Rua Dr. Xavier Sigaud 150, Urca, CEP 22290-180, Rio de Janeiro (Brazil)
2006-06-19T23:59:59.000Z
Quark matter is expected to exist in the interior of compact stellar objects as neutron stars or even the more exotic strange stars. Bare strange quark stars and (normal) strange quark-matter stars, those possessing a baryon (electron-supported) crust, are hypothesized as good candidates to explain the properties of a set of peculiar stellar sources. In this presentation, we modify the MIT Bag Model by including the electromagnetic interaction. We also show that this version of the MIT model implies the anisotropy of the Bag pressure due to the presence of the magnetic field. The equations of state of degenerate quarks gases are studied in the presence of ultra strong magnetic fields. The behavior of a system made-up of quarks having (or not) anomalous magnetic moment is reviewed. A structural instability is found, which is related to the anisotropic nature of the pressures in this highly magnetized matter.
Quarks with Integer Electric Charge
J. LaChapelle
2015-01-26T23:59:59.000Z
Within the context of the Standard Model, quarks are placed in a $(\\mathbf{3},\\mathbf{2})\\oplus (\\mathbf{3},\\bar{\\mathbf{2}})$ matter field representation of $U_{EW}(2)$. Although the quarks carry unit intrinsic electric charge in this construction, anomaly cancellation constrains the Lagrangian in such a way that the quarks' associated currents couple to the photon with the usual 2/3 and 1/3 fractional electric charge associated with conventional quarks. The resulting model is identical to the Standard Model in the $SU_C(3)$ sector: However, in the $U_{EW}(2)$ sector it is similar but not necessarily equivalent. Off hand, the model appears to be phenomenologically equivalent to the conventional quark model in the electroweak sector for experimental conditions that preclude observation of individual constituent currents. On the other hand, it is conceivable that detailed analyses for electroweak reactions may reveal discrepancies with the Standard Model in high energy and/or large momentum transfer reactions. The possibility of quarks with integer electric charge strongly suggests the notion that leptons and quarks are merely different manifestations of the same underlying field. A speculative model is proposed in which a phase transition is assumed to occur between $SU_C(3)\\otimes U_{EM}(1)$ and $U_{EM}(1)$ regimes. This immediately; explains the equality of lepton/quark generations and lepton/hadron electric charge, relates neutrino oscillations to quark flavor mixing, reduces the free parameters of the Standard Model, and renders the issue of quark confinement moot.
Relation between quark-antiquark potential and quark-antiquark free energy in hadronic matter
Zhen-Yu Shen; Xiao-Ming Xu
2014-06-19T23:59:59.000Z
We study the relation between the quark-antiquark potential and the quark-antiquark free energy in hadronic matter. While a temperature is over the critical temperature, the potential of a heavy quark and a heavy antiquark almost equals the free energy, otherwise the quark-antiquark potential is substantially larger than the quark-antiquark free energy. While a temperature is below the critical temperature, the quark-antiquark free energy can be taken as the quark-antiquark potential.
Quark Propagation in the Quark-Gluon Plasma
Xiangdong Li; Hu Li; C. M. Shakin; Qing Sun
2004-03-05T23:59:59.000Z
It has recently been suggested that the quark-gluon plasma formed in heavy-ion collisions behaves as a nearly ideal fluid. That behavior may be understood if the quark and antiquark mean-free- paths are very small in the system, leading to a "sticky molasses" description of the plasma, as advocated by the Stony Brook group. This behavior may be traced to the fact that there are relatively low-energy $q\\bar{q}$ resonance states in the plasma leading to very large scattering lengths for the quarks. These resonances have been found in lattice simulation of QCD using the maximum entropy method (MEM). We have used a chiral quark model, which provides a simple representation of effects due to instanton dynamics, to study the resonances obtained using the MEM scheme. In the present work we use our model to study the optical potential of a quark in the quark-gluon plasma and calculate the quark mean-free-path. Our results represent a specific example of the dynamics of the plasma as described by the Stony Brook group.
Mock, A
1997-01-01T23:59:59.000Z
Produktion von geladenen Pionen und Kaonen, Protonen, Antiprotonen und $\\phi$-Mesonen in ultrarelativistischen Blei-Blei-Stossen bei 158 GeV pro Nukleon
On quark-lepton complementarity
F. Gonzalez-Canales; A. Mondragon
2006-06-16T23:59:59.000Z
Recent measurements of the neutrino solar mixing angle and the Cabibbo angle satisfy the empirical relation theta_{sol} + theta_{C} ~ 45^{o}. This relation suggests the existence of a correlation between the mixing matrices of leptons and quarks, the so called quark-lepton complementarity. Here, we examine the possibility that this correlation originates in the strong hierarchy in the mass spectra of quarks and charged leptons, and the seesaw mechanism that gives mass to the Majorana neutrinos. In a unified treatment of quarks and leptons in which the mass matrices of all fermions have a similar Fritzsch texture, we calculate the mixing matrices V_{CKM} and U_{MNSP} as functions of quark and lepton masses and only two free parameters, in very good agreement with the latest experimental values on masses and mixings. Three essential ingredients to explain the quark-lepton complementarity relation are identified: the strong hierarchy in the mass spectra of quarks and charged leptons, the normal seesaw mechanism and the assumption of maximal CP violation in the lepton sector.
On quark-lepton complementarity
Gonzalez Canales, F.; Mondragon, A. [Instituto de Fisica, UNAM, 04510, Mexico D.F. (Mexico)
2006-09-25T23:59:59.000Z
Recent measurements of the neutrino solar mixing angle and the Cabibbo angle satisfy the empirical relation {theta}{sub sol} + {theta}{sub C} {approx_equal} ({pi}/4). This relation suggests the existence of a correlation between the mixing matrices of leptons and quarks, the so called quark-lepton complementarity. Here, we examine the possibility that this correlation originates in the strong hierarchy in the mass spectra of quarks and charged leptons, and the seesaw mechanism that gives mass to the Majorana neutrinos. In a unified treatment of quarks and leptons in which the mass matrices of all fermions have a similar Fritzsch texture, we calculate the mixing matrices VCKM and UMNSP as functions of quark and lepton masses and only two free parameters, in very good agreement with the latest experimental values on masses and mixings. Three essential ingredients to explain the quark-lepton complementarity relation are identified: the strong hierarchy in the mass spectra of quarks and charged leptons, the normal seesaw mechanism and the assumption of maximal CP violation in the lepton sector.
Ullmann, G. Matthias
Elektronik oder auf dem Gebiet der Gewinnung und Nutzung erneuerbarer Energien. ,,Wir freuen uns und sind
Shear Viscosity of Quark Matter
W. M. Alberico; S. Chiacchiera; H. Hansen; A. Molinari; M. Nardi
2007-07-30T23:59:59.000Z
We consider the shear viscosity of a system of quarks and its ratio to the entropy density above the critical temperature for deconfinement. Both quantities are derived and computed for different modeling of the quark self-energy, also allowing for a temperature dependence of the effective mass and width. The behaviour of the viscosity and the entropy density is argued in terms of the strength of the coupling and of the main characteristics of the quark self-energy. A comparison with existing results is also discussed.
Top quark studies at hadron colliders
Sinervo, P.K. [Univ. of Toronto, Ontario (Canada)
1997-01-01T23:59:59.000Z
The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.
Top Quark Production at the Tevatron Collider
Liang Li
2011-07-21T23:59:59.000Z
Top quark physics has been a rich testing ground for the standard model since the top quark discovery in 1995. The large mass of top quark suggests that it could play a special role in searches for new phenomena. In this paper I provide an overview of recent top quark production cross section measurements from both CDF and D0 collaborations and also some new physics searches done in the top quark sector.
Top Quark Production at the Tevatron Collider
Li, Liang; /UC, Riverside
2011-07-01T23:59:59.000Z
Top quark physics has been a rich testing ground for the standard model since the top quark discovery in 1995. The large mass of top quark suggests that it could play a special role in searches for new phenomena. In this paper I provide an overview of recent top quark production cross section measurements from both CDF and D0 collaborations and also some new physics searches done in the top quark sector.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kong, Kyoungchui; Lee, Hye-Sung; Park, Myeonhun
2014-04-01T23:59:59.000Z
We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 ? deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t ? b W + Z's. This is the same as the dominant topmore »quark decay (t ? b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kong, Kyoungchui [Kansas; Lee, Hye-Sung [W&M, JLAB; Park, Myeonhun [Tokyo
2014-04-01T23:59:59.000Z
We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 ? deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t ? b W + Z's. This is the same as the dominant top quark decay (t ? b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.
Fakultt fr Mathematik und Informatik Abteilung Didaktik
Knüpfer, Christian
nichteuklidischen Räumen sowie zur Lehrerbildung, wobei Ungarn aus DDR-Perspektive, wie Prof. Böhm betonte, als Problemlösen auf dem Gebiet der Stochastik unter besonderer Berücksichtigung der neuen Abiturprüfung in Ungarn Problemlösen durch Modellieren Im Vortrag wird der Stochastikunterricht in Ungarn durch konkrete Probleme und
PHILOSOPHIE Geschichte und Klassische Texte der Philosophie
Pfeifer, Holger
24 / 251 Grundfragen der Ethik (EPG I) Dr. Hans-Klaus Keul, UniversitÃ¤t Ulm Seminar, Di 17 /104 Religion und Evolution. Ende oder Wende, Anpassung oder Paradigmenwechsel? Prof. Dr. Roman Bauer Schule (EPG II) Dr. Gisela Badura-Lotter, Dr. Christiane Imhoff, Dr. Hans-Klaus Keul Kompaktseminar, Fr
A. W. Jung
2014-10-14T23:59:59.000Z
Recent measurements of top-quark properties at the LHC and the Tevatron are presented. Most recent measurements of the top quark mass have been carried out by CMS using $19.7/$fb of $\\sqrt{s} = 8$ TeV data including the study of the dependence on event kinematics. ATLAS uses the full Run I data at $\\sqrt{s} = 7$ TeV for a "3D" measurement that significantly reduces systematic uncertainties. D0 employs the full Run II data using the matrix element method to measure the top quark mass with significantly reduced systematic uncertainties. Many different measurements of the top quark exist to date and the most precise ones per decay channel per experiment have been combined into the first world combination with a relative precision of 0.44%. Latest updates of measurements of production asymmetries include the measurement of the \\ttbar production asymmetry by D0 employing the full Run II data set, by CMS and ATLAS (including the polarization of the top quark) employing both the full data set at $\\sqrt{s} = 7$ TeV. CMS uses the full $\\sqrt{s} = 8$ TeV data to measure the top quark polarization in single top production, the ratio ${\\cal R}$ of the branching fractions ${\\cal B}(t \\rightarrow Wb) / {\\cal B}(t \\rightarrow Wq)$ and to search for flavor changing neutral currents. The results from all these measurements agree well with their respective Standard Model expectation.
Diekmann, Martin
Software Engineering" an der Universität Bremen mit dem Weiterbildenden Studium ,,Softwareentwicklung und Software Engineering" mit Zertifikatsabschluss und Weiterbildungskursen im Bereich ,,Softwareentwicklung und Software Engineering" mit Zertifikatsabschluss vom 29. Oktober 2014 Der Fachbereichsrat 3
Studien-und Prfungsordnung der Universitt Stuttgart fr den Bachelorstudiengang Erneuerbare Energien
Reyle, Uwe
nachstehende Studien- und Prüfungsordnung für den Bachelorstudiengang Erneuerbare Energien beschlossen. Der Studien- und Prüfungsordnung für den Bachelorstudiengang Erneuerbare Energien beschreibt den Aufbau desStudien- und Prüfungsordnung der Universität Stuttgart für den Bachelorstudiengang Erneuerbare
Reggelin, Michael
Team MINT: Fachteam Mathematik, Informatik, Natur- und Ingenieurwissenschaften Stadtmitte Team Human: Fachteam Humanwissenschaften Team GeWiss: Fachteam Gesellschafts- und Geschichtswissenschaften Team Zentr. Info: Team Zentrale Information, P icht und elektronisches Publizieren Team ReWir: Fachteam
Entel, P.
Computersimulationen martensitischer Phasen¨uberg¨ange in Eisen-Nickel- und Nickel Molekulardynamik-Simulationen der martensitischen Umwandlungen in Eisen-Nickel- und Nickel Anpassung parametrisierter Funktionen an experimentelle Daten von Eisen, Nickel, Aluminium und NiAl gewonnen
Tomography of the Quark-Gluon-Plasma by Charm Quarks
Taesoo Song; Hamza Berrehrah; Daniel Cabrera; Juan M. Torres-Rincon; Laura Tolos; Wolfgang Cassing; Elena Bratkovskaya
2015-07-02T23:59:59.000Z
We study charm production in ultra-relativistic heavy-ion collisions by using the Parton-Hadron-String Dynamics (PHSD) transport approach. The initial charm quarks are produced by the Pythia event generator tuned to fit the transverse momentum spectrum and rapidity distribution of charm quarks from Fixed-Order Next-to-Leading Logarithm (FONLL) calculations. The produced charm quarks scatter in the quark-gluon plasma (QGP) with the off-shell partons whose masses and widths are given by the Dynamical Quasi-Particle Model (DQPM) which reproduces the lattice QCD equation-of-state in thermal equilibrium. The relevant cross section are calculated in a consistent way by employing the effective propagators and couplings from the DQPM. Close to the critical energy density of the phase transition, the charm quarks are hadronized into $D$ mesons through coalescence and/or fragmentation depending on transverse momentum. The hadronized $D$ mesons then interact with the various hadrons in the hadronic phase with cross sections calculated in an effective lagrangian approach with heavy-quark spin symmetry. Finally, the nuclear modification factor $\\rm R_{AA}$ and the elliptic flow $v_2$ of $D^0$ mesons from PHSD are compared with the experimental data from the STAR Collaboration for Au+Au collisions at $\\sqrt{s_{\\rm NN}}$ =200 GeV. We find that in the PHSD the energy loss of $D$ mesons at high $p_T$ can be dominantly attributed to partonic scattering while the actual shape of $\\rm R_{AA}$ versus $p_T$ reflects the heavy quark hadronization scenario, i.e. coalescence versus fragmentation. Also the hadronic rescattering is important for the $\\rm R_{AA}$ at low $p_T$ and enhances the $D$-meson elliptic flow $v_2$.
Tomography of the Quark-Gluon-Plasma by Charm Quarks
Song, Taesoo; Cabrera, Daniel; Torres-Rincon, Juan M; Tolos, Laura; Cassing, Wolfgang; Bratkovskaya, Elena
2015-01-01T23:59:59.000Z
We study charm production in ultra-relativistic heavy-ion collisions by using the Parton-Hadron-String Dynamics (PHSD) transport approach. The initial charm quarks are produced by the Pythia event generator tuned to fit the transverse momentum spectrum and rapidity distribution of charm quarks from Fixed-Order Next-to-Leading Logarithm (FONLL) calculations. The produced charm quarks scatter in the quark-gluon plasma (QGP) with the off-shell partons whose masses and widths are given by the Dynamical Quasi-Particle Model (DQPM) which reproduces the lattice QCD equation-of-state in thermal equilibrium. The relevant cross section are calculated in a consistent way by employing the effective propagators and couplings from the DQPM. Close to the critical energy density of the phase transition, the charm quarks are hadronized into $D$ mesons through coalescence and/or fragmentation depending on transverse momentum. The hadronized $D$ mesons then interact with the various hadrons in the hadronic phase with cross sect...
Musterlsung: AlgoDat (Magister) 1. Serie 1.) 3 Pkt. Obere, Untere und Exakte Schranke
Der, Ralf
nngnngnOng b) nnn cng 2222)( 1010 ××== + 10 n und 1024=c nnn cng 2222)( 1010 ××== + 10 n und 1024=c )2
Quarks and Antiquarks in Nuclei
Jason R. Smith
2005-08-19T23:59:59.000Z
The Chiral Quark-Soliton model provides the quark and antiquark substructure of the nucleon, which is embedded in nuclear matter. This provides a new way to asses the effects of the nuclear medium on the nucleon. We calculate nuclear binding and saturation, describe the European Muon Collaboration (EMC) effect consistently with Drell-Yan experiments, and predict modifications to the polarized parton distributions. We also calculate the electromagnetic form factors of a bound proton, and find significant modifications of the electromagnetic form factors in the nuclear environment. In every case, the properties of the sea of quark-antiquark pairs in the nucleon are very important, and serve to mitigate the valence quark effect. The changes in the sea quarks when the nucleon is immersed in the nuclear medium are the primary mode by which consistency is maintained with experimental constraints (Drell-Yan data, magnetic moment), while still maintaining a significant effect needed to explain the deep inelastic scattering and polarization transfer data.
Thermalization of heavy quarks in the quark-gluon plasma
van Hees, H.; Rapp, Ralf.
2005-01-01T23:59:59.000Z
the kinetic equilibration of c quarks as compared to using perturbative interactions. We also comment on consequences for D-meson observables in ultrarelativistic heavy-ion collisions. DOI: 10.1103/PhysRevC.71.034907 PACS number(s): 12.38.Mh, 24.85.+p, 25... of individual c quarks in the QGP will reflect themselves in transverse- momentum (pT -) spectra of open charm hadrons (D mesons) [4?7], most notably their elliptic flow, v2(pT ), in semicentral collisions [8,9]. Preliminary experimental results from...
Statistik und Numerik Vorlesung Prof. Dr. Jens Timmer
Timmer, Jens
in Matlab ¨uber den Befehl f = @(lambda) g(x0+lambda*u) definiert. Um die Bedingungen 0 pi 1 und N i=1
Cédric Lorcé
2014-09-16T23:59:59.000Z
The proton spin puzzle issue focused the attention on the parton spin and orbital angular momentum contributions to the proton spin. However, a complete characterization of the proton spin structure requires also the knowledge of the parton spin-orbit correlation. We showed that this quantity can be expressed in terms of moments of measurable parton distributions. Using the available phenomenological information about the valence quarks, we concluded that this correlation is negative, meaning that the valence quark spin and kinetic orbital angular momentum are, in average, opposite. The quark spin-orbit correlation can also be expressed more intuitively in terms of relativistic phase-space distributions, which can be seen as the mother distributions of the standard generalized and transverse-momentum dependent parton distributions. We present here for the first time some examples of the general multipole decomposition of these phase-space distributions.
Nuclear Matter with Relativistic Quark Dynamics
Suisso, E.F.; Batista, E.F.; Araujo, W.R.B. de; Frederico, T.; Carlson, B.V. [Dep. de Fisica, Instituto Tecnologico da Aeronautca, Centro Tecnico Aeroespacial, 12.228-901, Sao Jose dos Campos, Sao Paulo (Brazil)
2004-12-02T23:59:59.000Z
We investigate a quark-meson coupling model of the nuclear matter with a light-front nucleon model, where the quarks interact with flavor independent contact force. We found results comparable to the ones obtained with a confining interaction.
Quark stars: their influence on Astroparticle Physics
Sanjay K. Ghosh
2008-08-12T23:59:59.000Z
We discuss some of the recent developments in the quark star physics along with the consequences of possible hadron to quark phase transition at high density scenario of neutron stars and their implications on the Astroparticle Physics.
Quark masses: An environmental impact statement
Kimchi, Itamar
We investigate worlds that lie on a slice through the parameter space of the standard model over which quark masses vary. We allow as many as three quarks to participate in nuclei, while fixing the mass of the electron and ...
Top Quark Production at the LHC
Francesco Spanò; for the ATLAS; CMS collaborations
2011-12-16T23:59:59.000Z
Top quark production in proton proton collisions at the Large Hadron Collider (LHC) is reviewed using data collected by the ATLAS and CMS detectors. Most recent results on searches for new physics related to top quark production mechanism are included.
Werner Bernreuther
2008-05-09T23:59:59.000Z
The physics perspectives of the production and decay of single top quarks and top quark pairs at the CERN Large Hadron Collider (LHC) are reviewed from a phenomenological point of view.
Villafranca Die Kabinete und die Revolutionen.
Prodinger, Helmut
TheiÃ? an ihrer Verbindung mit dem KÃ¶rÃ¶s gefÃ¼hrt haben, in denen die Revolu- tion Ungarns sich entspann bereits in einem frÃ¼heren Bande erwÃ¤hnt, und wie der wilde Racen- krieg in Ungarn selbst schon seit dem. Noch ehe das Jahr zu Ende, rÃ¼ckte die Kaiserliche Armee unter WindischgrÃ¤tz in Ungarn ein. Rasch
Top Quark: discovery, present and future Galtieri, The Top Quark, PDG 50th
Galtieri, Lina
1 Top Quark: discovery, present and future Galtieri, The Top Quark, PDG 50th Anniversary. September 23-2006 #12;Chasing the Top Quark 2 Gell-Mann, Zweig uds quarks postulated ('64) GIM mechanism at FNAL 1984 PDG partial listing top should exist Searches at Tristan, PETRA, SPPS, SLC : top not found
Valence Quarks Polarization from COMPASS
A. Korzenev
2007-04-26T23:59:59.000Z
A first evaluation of the polarized valence quark distribution $\\Delta u_v(x)+\\Delta d_v(x)$ from the COMPASS experiment (CERN/SPS) is presented. The data were collected by COMPASS in the years 2002--2004 using a 160 GeV polarized muon beam scattered off a large polarized $^6$LiD target and cover the range $1< Q^2 < 100$ GeV$^2$ and $0.006
Spontaneously broken quark helicity symmetry
Dalley, Simon [Department of Physics, University of Wales Swansea, Singleton Park, Swansea SA2 8PP (United Kingdom); McCartor, Gary [Department of Physics, SMU Dallas, TX 75275 (United States)]. E-mail: mccartor@mail.physics.smu.edu
2006-02-15T23:59:59.000Z
We discuss the origin of chiral-symmetry breaking in the light-cone representation of QCD. In particular, we show how quark helicity symmetry is spontaneously broken in SU (N) gauge theory with massless quarks if that theory has a condensate of fermion light-cone zero modes. The symmetry breaking appears as induced interactions in an effective light-cone Hamiltonian equation based on a trivial vacuum. The induced interaction is crucial for generating a splitting between pseudoscalar and vector meson masses, which we illustrate with spectrum calculations in some 1 + 1-dimensional reduced models of gauge theory.
Top quark Physics at the Tevatron
Yvonne Peters; for the CDF; D0 Collaborations
2012-01-06T23:59:59.000Z
When the heaviest elementary particle known today, the top quark, was discovered in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron collider, a large program to study this particle in details has started. In this article, an overview of the status of top quark physics at the Tevatron is presented. In particular, recent results on top quark production, properties and searches using top quarks are discussed.
Chaotic dynamics in quark-gluon cascade
A. T. Temiraliev
2011-06-23T23:59:59.000Z
A map to the quark-gluon cascade on the basis of nonlinearity in the quark and gluon distributions in hadrons is proposed. Calculations of the quarks trajectories have shown the presence of the chaotic dynamics as a consequence of bifurcations.
Exotic hybrid mesons with light quarks
Claude Bernard; Tom Blum; Thomas A. DeGrand; Carleton DeTar; Steven Gottlieb; Urs. M. Heller; Jim Hetrick; Craig McNeile; Kari Rummukainen; Bob Sugar; Doug Toussaint; Matt Wingate
1996-07-12T23:59:59.000Z
Hybrid mesons, made from a quark, an antiquark and gluons, can have quantum numbers inaccessible to conventional quark-antiquark states. Confirmation of such states would give information on the role of "dynamical" color in low energy QCD. We present preliminary results for hybrid meson masses using light Wilson valence quarks.
Regelsysteme 1 10. Tutorial LQ Regulator und Kalman Filter
Lygeros, John
Regelsysteme 1 10. Tutorial LQ Regulator und Kalman Filter Dave Ochsenbein Institut f¨ur Automatik ETH Z¨urich HS 2013 Dave Ochsenbein Regelsysteme 1 HS 2013 #12;10. Tutorial LQ Regulator und Kalman Filter Gliederung 10.1. Varia 10.2. LQ-Regulator 10.3. Kalman-Bucy Filter 10.4. Eigenschaften des
2000-Liter-Gesellschaft --Entwicklungschance fr Nord und Sd
Wehrli, Bernhard
2000-Liter-Gesellschaft -- Entwicklungschance für Nord und Süd Die Schweizerische Umweltstiftung initiiert die Real-Vision der 2000-Liter- Gesellschaft um den Wasserverbrauch von weltweit rund 4'000 Litern pro Person und Tag auf 2'000 Liter zu reduzieren. Die 2000-Liter-Gesellschaft ist das
Energie-und Leistungsbilanzierung im MICRO GRID eines industriellen Produktionsstandortes mit
Paderborn, Universität
an das lokale MICRO GRID angeschlossenen elektrischen Energiespeicher und eine ,,POWER TO GAS" -Anlage
Fachgebiet Methoden der Produktentwicklung und Mechatronik Prof. Dr.-Ing. D. Ghlich
Berlin,Technische Universität
Betriebshofs und die Verfügbarkeit der Energiespeicher für das Versorgungsnetz dargestellt werden. Im zweiten
Paderborn, Universität
durch einen ebenfalls an das lokale MICRO GRID angeschlossenen elektrischen Energiespeicher und eine
Nr. 314 / 2012 // 5. Dez. 2012 Imperien diesseits und jenseits des Atlantiks
Ullmann, G. Matthias
, Großbritannien, Frankreich, Schweden, Polen, Ungarn und Deutschland für die Teilnahme an der Konfe- renz zu
Nr. 05 | 25.04.2012 THE LARGER PICTURE | NEWSLETTER INTERNATIONAL UND INTERKULTURELL
Hinrichs, Klaus
Finnland, Ungarn und der Schweiz erwartet. ,,Wir wollen mit der Konferenz einen länderüber- greifenden
Uni internationalU-Mail 1/07 Regensburger Universittszeitung 5 Das Thema ,,Verantwortung und Eliten"
Schubart, Christoph
, Tschechien und Ungarn offen. Über 40 Jahresstipendiaten aus diesen Ländern trafen sich Ende November
Schmidt, Matthias
- und Umweltprobleme." Also im Wortsinne weltbewegend. Ein gro- ßer Teil der aktuellen Umweltproble- me
Teil 1: Neueste wissenschaftliche Erkenntnisse und Technologien 15.00 Uhr Begrssung
, erneuerbare Energien, Elektrifizierung Technik und Infrastruktur zur erfolgreichen Umsetzung in der Praxis
Quark hadronization probed by K(0) mesons
Baringer, Philip S.
1990-04-01T23:59:59.000Z
are well understood in the context of QCD. A quark-antiquark pair with large virtuality (or qz) evolves through a parton shower of quarks and gluons of decreas- ing virtuality. So long as the parton virtuality is large, a, is small and the perturbative... /CP) is given in Fig. 7(a) for tracks opposite the D' tag. These tracks come from the fragmentation of a known 14.5-GeV c (or c) 200 (a)Vebber 4. 1 —c quark events Lund 6.3 — c quark events R(Ko/Charged) opposite D tag 100 (b) WEBBER 4.1: u quark...
R. Y. Peters
2014-08-10T23:59:59.000Z
Years after its discovery in 1995 by CDF and D0, the top quark still undergoes intense investigations at the Tevatron. Using up to the full Run~II data sample, new measurements of top quark production and properties by the D0 Collaboration are presented. In particular, the first observation of single top quark s-channel production, the measurement of differential ttbar distributions, forward-backward ttbar asymmetry, a new measurement of the top quark mass, and a measurement of the top quark charge are discussed.
Top-Quark Physics Results From LHC
Luca Fiorini
2012-01-30T23:59:59.000Z
The top-quark is a fundamental element of the physics program at the Large Hadron Collider (LHC). We review the current status of the top-quark measurements performed by ATLAS and CMS experiments in pp collisions at sqrt(s)=7 TeV by presenting the recent results of the top-quark production rates, top mass measurements and additional top quark properties. We will also describe the recent searches for physics beyond the Standard Model in the top-quark sector.
Top Quark Physics at the Tevatron
Frederic Deliot; Douglas Glenzinski
2011-10-10T23:59:59.000Z
We review the field of top-quark physics with an emphasis on experimental techniques. The role of the top quark in the Standard Model of particle physics is summarized and the basic phenomenology of top-quark production and decay is introduced. We discuss how contributions from physics beyond the Standard Model could affect top-quark properties or event samples. The many measurements made at the Fermilab Tevatron, which test the Standard Model predictions or probe for direct evidence of new physics using the top-quark event samples, are reviewed here.
Steinhoff, Heinz-Jürgen
System SAP Business Objects als einziges BI-System eingesetzt werden. Der Flughafen arbeitet mit dem ERP-System Controlling wurde das System SAP Business Objects angeschafft, in welches bereits die relevanten Daten aus der1 Projektangebote für das IS-Project (WS 2013/2014 und SS 2014) Fachgebiet Unternehmensrechnung und
Top quark physics in hadron collisions
Wolfgang Wagner
2007-08-03T23:59:59.000Z
The top quark is the heaviest elementary particle observed to date. Its large mass makes the top quark an ideal laboratory to test predictions of perturbation theory concerning heavy quark production at hadron colliders. The top quark is also a powerful probe for new phenomena beyond the Standard Model of particle physics. In addition, the top quark mass is a crucial parameter for scrutinizing the Standard Model in electroweak precision tests and for predicting the mass of the yet unobserved Higgs boson. Ten years after the discovery of the top quark at the Fermilab Tevatron top quark physics has entered an era where detailed measurements of top quark properties are undertaken. In this review article an introduction to the phenomenology of top quark production in hadron collisions is given, the lessons learned in Tevatron Run I are summarized, and first Run II results are discussed. A brief outlook to the possibilities of top quark research a the Large Hadron Collider, currently under construction at CERN, is included.
Light quark masses using domain wall fermions
Tom Blum; Amarjit Soni; Matthew Wingate
1998-09-10T23:59:59.000Z
We compute the one-loop self-energy correction to the massive domain wall quark propagator. Combining this calculation with simulations at several gauge couplings, we estimate the strange quark mass in the continuum limit. The perturbative one-loop mass renormalization is comparable to that for Wilson quarks and considerably smaller than that for Kogut-Susskind quarks. Also, scaling violations appear mild in comparison to other errors at present. Given their good chiral behavior and these features, domain wall quarks are attractive for evaluating the light quark masses. Our preliminary quenched result is m_s(2 GeV) = 82(15) MeV in the ${\\bar{MS}}$ scheme.
Röder, Beate
dissertation-hu und dissonline, Version 6.1 (25.2.2013) Dissertationen und Habilitationsschriften mit Microsoft Word Leitfaden zu den Dokumentvorlagen »dissertation-hu« »dissonline« Version 6.1 (25.2.2013) gefördert Dokumentvorlagen dissertation-hu und dissonline, Version 6.1 (25.2.2013) Impressum Herausgegeben durch: Humboldt
Ould Ahmedou, Mohameden
Entwurf und Verifikation von Hardware/Software - SystemenEntwurf und Verifikation von Hardware/Software-Level- Konfigurat. Software: C/C++ global Header Skript-basierte Konfiguration Analyse- datenbank SystemC Simulation Bewertung hardwarenaher SoftwareEntwurf und Bewertung hardwarenaher Software C C R T OS R T OS PV / PVT PV
Top quark properties at the Tevatron
Andreas Werner Jung
2014-12-12T23:59:59.000Z
Recent measurements of top-quark properties at the Tevatron, including top quark production asymmetries and properties, are presented. Latest updates of measurements of top quark production asymmetries include the measurement of the $t\\bar{t}$ production asymmetry by D0 employing the full Run II data set, in the lepton + jets and dilepton decay channel. Within their uncertainties the results from all these measurements agree with their respective Standard Model expectation.
Detecting Fourth Generation Quarks at Hadron Colliders
David Atwood; Sudhir Kumar Gupta; Amarjit Soni
2011-07-13T23:59:59.000Z
We consider the phenomenology of the fourth generation heavy quarks which would be pair produced at the LHC. We show that if such a quark with a mass in the phenomenologically interesting range of 400 GeV--600 GeV decays to a light quark and a W-boson, it will produce a signal in a number of channels which can be seen above the background from the three generation Standard Model processes. In particular, such quarks could be seen in channels where multiple jets are present with large missing momentum and either a single hard lepton, an opposite sign hard lepton pair or a same sign lepton pair. In the same sign dilepton channel there is little background and so an excess of such pairs at large invariant mass will indicate the presence of heavy down type quarks. More generally, in our study, the main tool we use to determine the mass of the heavy quark in each of the channels we consider is to use the kinematics of the decay of such quarks to resolve the momenta of the unobserved neutrinos. We show how this can be carried out, even in cases where the kinematics is under-determined by use of the approximation, which holds quite well, that the two heavy quarks are nearly at rest in the center of mass frame. Since it is very likely that at least the lightest heavy quark decays in the mode we consider, this means that it should be observed at the LHC. Indeed, it is expected that the mass splitting between the quarks is less than $m_W$ so that if the Cabbibo-Kobayshi-Maskawa (CKM) matrix element between the fourth and lower generations are not too small, both members of the fourth generation quark doublet will decay in this way. If this is so, the combined signal of these two quarks will make the signal for the fourth generation somewhat more prominent.
Single top quark production at D0
Reinhard Schwienhorst; for the D0 collaboration
2011-09-13T23:59:59.000Z
Updates of electroweak single top quark production measurements by the D0 collaboration are presented using 5.4fb^-1 of proton-antiproton collision data from the Tevatron at Fermilab. Measurements of the t-channel, s-channel and combined single top quark production cross section are presented, including an updated lower limit on the CKM matrix element |V_tb|. Also reported are results from searches for gluon-quark flavor-changing neutral currents and W' boson production.
Jet substructures of boosted polarized top quarks
Yoshio Kitadono; Hsiang-nan Li
2014-09-05T23:59:59.000Z
We study jet substructures of a boosted polarized top quark, which undergoes the semileptonic decay $t\\to b\\ell\
Top Quark Production Asymmetries AFBt and AFBl
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Berger, Edmond L.; Cao, Qing-Hong; Chen, Chuan-Ren; Yu, Jiang-Hao; Zhang, Hao
2012-02-01T23:59:59.000Z
A large forward-backward asymmetry is seen in both the top quark rapidity distribution AFBt and in the rapidity distribution of charged leptons AFBl from top quarks produced at the Tevatron. We study the kinematic and dynamic aspects of the relationship of the two observables arising from the spin correlation between the charged lepton and the top quark with different polarization states. We emphasize the value of both measurements, and we conclude that a new physics model which produces more right-handed than left-handed top quarks is favored by the present data.
Collisional energy loss of heavy quarks
Alex Meistrenko; Andre Peshier; Jan Uphoff; Carsten Greiner
2013-04-13T23:59:59.000Z
We develop a transport approach for heavy quarks in a quark-gluon plasma, which is based on improved binary collision rates taking into account quantum statistics, the running of the QCD coupling and an effective screening mass adjusted to hard-thermal loop calculations. We quantify the effects of in-medium collisions by calculating the heavy flavor nuclear modification factor and the elliptic flow for RHIC energies, which are comparable to radiative effects. We also derive an analytic formula for the mean collisional energy loss of an energetic heavy quark in a streaming quark gluon plasma.
Top Quark Physics at the CDF Experiment
Bernd Stelzer; for the CDF Collaboration
2010-07-21T23:59:59.000Z
Fermilab's Tevatron accelerator is recently performing at record luminosities that enables a program systematically addressing the physics of top quarks. The CDF collaboration has analyzed up to 5/fb of proton anti-proton collisions from the Tevatron at a center of mass energy of 1.96 TeV. The large datasets available allow to push top quark measurements to higher and higher precision and have lead to the recent observation of electroweak single top quark production at the Tevatron. This article reviews recent results on top quark physics from the CDF experiment.
Single Top Quarks at the Tevatron
A. P. Heinson
2008-09-05T23:59:59.000Z
After many years searching for electroweak production of top quarks, the Tevatron collider experiments have now moved from obtaining first evidence for single top quark production to an impressive array of measurements that test the standard model in several directions. This paper describes measurements of the single top quark cross sections, limits set on the CKM matrix element |Vtb|, searches for production of single top quarks produced via flavor-changing neutral currents and from heavy W-prime and H+ boson resonances, and studies of anomalous Wtb couplings. It concludes with projections for future expected significance as the analyzed datasets grow.
Thermalization of heavy quarks in the quark-gluon plasma
van Hees, H.; Rapp, Ralf.
2005-01-01T23:59:59.000Z
the BNL Relativistic Heavy-Ion Collider (RHIC) indicate the possibility that the D-meson v2 could be similar in magnitude to the one of light hadrons [10,11]. Since the c quark is rather heavy, this would be quite remarkable and could provide important... temperature) has been suggested as a mechanism to enhance partonic cross sections [12?14] to facilitate rapid thermalization of the bulk matter at RHIC as required in hy- drodynamical models. The notion of charmonium resonances in the QGP [15,16] has been...
Name: Nicole Immig Habilitationsthema: Das Trken-und Osmanenbild in
Knüpfer, Christian
/Athen, Forschungsaufenthalt am Centre of Asia-Minor- Studies/Athen und am Institute of Balkan Studies/Thessaloniki 2005 Nafoeg and their Architectural Legacy in Arta and Thessaly, Konferenz Balkan Worlds (Thessaloniki, 5.-7. Okt. 2012
Das Institut fr Optische und Elekt ronische Materialien forscht an
Moeller, Ralf
performs research on materials and structures with exceptional optical and electronic properties. Optische Mustererkennung Viele Anwendungen erfordern die präzise Erfassung der Topographie Optischer 3D Hamburg Optische und Elektronische Materialien #12;The Institute of Optical and Elec tronic Materials
FTD/am; Quelle: MPI fr Dynamik und Selbstorganisation Pennsylvania
Amaral, Luis A.N.
Arkansas Pennsylvania New Mexico Kalifornien Bis hierher und nicht weiter Mobilitätsgrenzen in den USA medizini- sche Anwendungen entwickelt, der die Positronenemissionstomografie (PET) mit der Detektionsempfindlichkeit der PET verbunden werden. Bislang können allerdings nur kleine Labor- tiere untersucht werden. FTD
RAT FR MIGRATION e.V. Integration und Illegalitt
Kallenrode, May-Britt
RAT FÜR MIGRATION e.V. (RfM) Integration und Illegalität in Deutschland herausgegeben von Klaus J >Festung EuropaMigration. Von Klaus J. Bade Resolution des Rates für Migration zum Problem der aufenthaltsrechtlichen Illegalität
Top quark mass and properties at the Tevatron
J. -F. Arguin; for the CDF; D0 Collaborations
2005-07-29T23:59:59.000Z
We present recent analyses of top quark properties performed at Run II of the Tevatron. Measurements of the top quark mass, branching ratios and W boson helicity inside top quark decays are covered.
Quark Masses: An Environmental Impact Statement
Robert L. Jaffe; Alejandro Jenkins; Itamar Kimchi
2009-04-03T23:59:59.000Z
We investigate worlds that lie on a slice through the parameter space of the Standard Model over which quark masses vary. We allow as many as three quarks to participate in nuclei, while fixing the mass of the electron and the average mass of the lightest baryon flavor multiplet. We classify as "congenial" worlds that satisfy the environmental constraint that the quark masses allow for stable nuclei with charges one, six, and eight, making organic chemistry possible. Whether a congenial world actually produces observers depends on a multitude of historical contingencies, beginning with primordial nucleosynthesis, which we do not explore. Such constraints may be independently superimposed on our results. Environmental constraints such as the ones we study may be combined with information about the a priori distribution of quark masses over the landscape of possible universes to determine whether the measured values of the quark masses are determined environmentally, but our analysis is independent of such an anthropic approach. We estimate baryon masses as functions of quark masses and nuclear masses as functions of baryon masses. We check for the stability of nuclei against fission, strong particle emission, and weak nucleon emission. For two light quarks with charges 2/3 and -1/3, we find a band of congeniality roughly 29 MeV wide in their mass difference. We also find another, less robust region of congeniality with one light, charge -1/3 quark, and two heavier, approximately degenerate charge -1/3 and 2/3 quarks. No other assignment of light quark charges yields congenial worlds with two baryons participating in nuclei. We identify and discuss the region in quark-mass space where nuclei would be made from three or more baryon species.
A measurement of the top quark's charge
Unalan, Zeynep Gunay; /Michigan State U.
2007-11-01T23:59:59.000Z
The top quark was discovered in 1995 at the Fermilab National Accelerator Laboratory (Fermilab). One way to confirm if the observed top quark is really the top quark posited in the Standard Model (SM) is to measure its electric charge. In the Standard Model the top quark is the isospin partner of the bottom quark and is expected to have a charge of +2/3. However, an alternative 'exotic' model has been proposed with a fourth generation exotic quark that has the same characteristics, such as mass, as our observed top but with a charge of -4/3. This thesis presents the first CDF measurement of the top quark's charge via its decay products, a W boson and a bottom quark, using {approx} 1 fb{sup -1} of data. The data were collected by the CDF detector from proton anti-proton (p{bar p}) collisions at {radical}s = 1.96 TeV at Fermilab. We classify events depending on the charges of the bottom quark and associated W boson and count the number of events which appear 'SM-like' or 'exotic-like' with a SM-like event decaying as t {yields} W{sup +}b and an exotic event as t {yields} W{sup -}b. We find the p-value under the Standard Model hypothesis to be 0:35 which is consistent with the Standard Model. We exclude the exotic quark hypothesis at an 81% confidence level, for which we have chosen a priori that the probability of incorrectly rejecting the SM would be 1%. The calculated Bayes Factor (BF) is 2 x Ln(BF)=8.54 which is interpreted as the data strongly favors the Standard Model over the exotic quark hypothesis.
Schubart, Christoph
von Deutschland und Polen. Nach der Eröffnung durch den Dekan, Prof. Dr. Wlodzimierz Gromski, sprach Beilegung verbraucherrechtlicher Streitigkeiten in Deutschland und Polen, die Anwendung neuer
Relation between quark-antiquark potential and quark-antiquark free energy in hadronic matter
Zhen-Yu Shen; Xiao-Ming Xu
2015-07-07T23:59:59.000Z
In the high-temperature quark-gluon plasma and its subsequent hadronic matter created in a high-energy nucleus-nucleus collision, the quark-antiquark potential depends on the temperature. The temperature-dependent potential is expected to be derived from the free energy obtained in lattice gauge theory calculations. This requires one to study the relation between the quark-antiquark potential and the quark-antiquark free energy. When the system's temperature is above the critical temperature, the potential of a heavy quark and a heavy antiquark almost equals the free energy, but the potential of a light quark and a light antiquark, of a heavy quark and a light antiquark and of a light quark and a heavy antiquark is substantially larger than the free energy. When the system's temperature is below the critical temperature, the quark-antiquark free energy can be taken as the quark-antiquark potential. This allows one to apply the quark-antiquark free energy to study hadron properties and hadron-hadron reactions in hadronic matter.
Review of Top Quark Physics Results
Kehoe, R.; Narain, M.; Kumar, A.; ,
2007-12-01T23:59:59.000Z
As the heaviest known fundamental particle, the top quark has taken a central role in the study of fundamental interactions. Production of top quarks in pairs provides an important probe of strong interactions. The top quark mass is a key fundamental parameter which places a valuable constraint on the Higgs boson mass and electroweak symmetry breaking. Observations of the relative rates and kinematics of top quark final states constrain potential new physics. In many cases, the tests available with study of the top quark are both critical and unique. Large increases in data samples from the Fermilab Tevatron have been coupled with major improvements in experimental techniques to produce many new precision measurements of the top quark. The first direct evidence for electroweak production of top quarks has been obtained, with a resulting direct determination of V{sub tb}. Several of the properties of the top quark have been measured. Progress has also been made in obtaining improved limits on potential anomalous production and decay mechanisms. This review presents an overview of recent theoretical and experimental developments in this field. We also provide a brief discussion of the implications for further efforts.
Recent advances in heavy quark theory
Wise, M. [California Institute of Technology, Pasadena, CA (United States)
1997-01-01T23:59:59.000Z
Some recent developments in heavy quark theory are reviewed. Particular emphasis is given to inclusive weak decays of hadrons containing a b quark. The isospin violating hadronic decay D{sub s}* {yields} D{sub s}{sup pi}{sup 0} is also discussed.
Static quark free energies at finite temperature
Z. Fodor; A. Jakovac; S. D. Katz; K. K. Szabo
2007-10-22T23:59:59.000Z
We determine the static quark free energies around the transition temperature using 2+1 flavors of staggered fermions. Simulations are carried out on N_t=4,6,8 and 10 lattices using physical quark masses. The free energies extracted from Polyakov-loop correlators are extrapolated to the continuum limit.
Friction Coefficient for Quarks in Supergravity Duals
E. Antonyan
2006-11-22T23:59:59.000Z
We study quarks moving in strongly-coupled plasmas that have supergravity duals. We compute the friction coefficient of strings dual to such quarks for general static supergravity backgrounds near the horizon. Our results also show that a previous conjecture on the bound has to be modified and higher friction coefficients can be achieved.
Top quark physics expectations at the LHC
Andrei Gaponenko; for the ATLAS Collaboration; for the CMS Collaboration
2008-10-22T23:59:59.000Z
The top quark will be produced copiously at the LHC. This will make both detailed physics studies and the use of top quark decays for detector calibration possible. This talk reviews plans and prospects for top physics activities in the ATLAS and CMS experiments.
Heavy quark thermodynamics in full QCD
Konstantin Petrov; RBC-Bielefeld Collaboration
2007-01-22T23:59:59.000Z
We analyze the large-distance behaviour of static quark-anti-quark pair correlations in QCD. The singlet free energy is calculated and the entropy contribution to it is identified allowing us to calculate the excess internal energy. The free energy has a sharp drop in the critical region, leading to sharp peaks in both excess entropy and internal energy.
Static quark free energies at finite temperature with two flavors of improved Wilson quarks
Y. Maezawa; S. Ejiri; T. Hatsuda; N. Ishii; N. Ukita; S. Aoki; K. Kanaya
2006-10-02T23:59:59.000Z
Polyakov loop correlations at finite temperature in two-flavor QCD are studied in lattice simulations with the RG-improved gluon action and the clover-improved Wilson quark action. From the simulations on a $16^3 \\times 4$ lattice, we extract the free energies, the effective running coupling $g_{\\rm eff}(T)$ and the Debye screening mass $m_D(T)$ for various color channels of heavy quark--quark and quark--anti-quark pairs above the critical temperature. The free energies are well approximated by the screened Coulomb form with the appropriate Casimir factors. The magnitude and the temperature dependence of the Debye mass are compared to those of the next-to-leading order thermal perturbation theory and to a phenomenological formula given in terms of $g_{\\rm eff}(T)$. Also we made a comparison between our results with the Wilson quark and those with the staggered quark previously reported.
Tevatron Top-Quark Combinations and World Top-Quark Mass Combination
Reinhild Yvonne Peters; on behalf of the ATLAS; CDF; CMS; D0 collaborations
2014-11-04T23:59:59.000Z
Almost 20 years after its discovery, the top quark is still an interesting particle, undergoing precise investigation of its properties. For many years, the Tevatron proton antiproton collider at Fermilab was the only place to study top quarks in detail, while with the recent start of the LHC proton proton collider a top quark factory has opened. An important ingredient for the full understanding of the top quark is the combination of measurements from the individual experiments. In particular, the Tevaton combinations of single top-quark cross sections, the ttbar production cross section, the W helicity in top-quark decays as well as the Tevatron and the world combination of the top-quark mass are discussed.
M. Bishai
2002-12-13T23:59:59.000Z
Heavy quark production cross-sections, correlations and polarizations have been measured at the Collider Detector at Fermilab (CDF) using 118 pb{sup -1} of data collected from the 1992 to 1995 Run I of the Fermilab Tevatron. There is still disagreement between theoretical predictions of bottom and charm hadro-production cross-sections and the Run I results. The observed transverse momentum spectrum of the prompt J/{psi} production polarization is still not understood. Run II of the Tevatron began in July of 2001 and the CDF Run II detector [11] has collected 70 pb{sup -1} of physics quality data since January 2002. Large statistics of onia states have been collected. Exclusive B meson decay modes have been reconstructed and the SVT level 2 displaced track trigger has produced large samples of D mesons. The prompt charm and b {yields} cX fractions in both charmonium and D meson samples have been measured. Run II is now poised to greatly enhance the knowledge of heavy quark production dynamics well beyond the reach of the Run I detector.
The QCD spectrum with three quark flavors
Claude Bernard; Tom Burch; Thomas A. DeGrand; Saumen Datta; Carleton DeTar; Steven Gottlieb; Urs M. Heller; Kostas Orginos; Robert Sugar; Doug Toussaint
2001-05-29T23:59:59.000Z
We present results from a lattice hadron spectrum calculation using three flavors of dynamical quarks - two light and one strange, and quenched simulations for comparison. These simulations were done using a one-loop Symanzik improved gauge action and an improved Kogut-Susskind quark action. The lattice spacings, and hence also the physical volumes, were tuned to be the same in all the runs to better expose differences due to flavor number. Lattice spacings were tuned using the static quark potential, so as a byproduct we obtain updated results for the effect of sea quarks on the static quark potential. We find indications that the full QCD meson spectrum is in better agreement with experiment than the quenched spectrum. For the 0++ (a0) meson we see a coupling to two pseudoscalar mesons, or a meson decay on the lattice.
Quarks and gluons in hadrons and nuclei
Close, F.E. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA))
1989-12-01T23:59:59.000Z
These lectures discuss the particle-nuclear interface -- a general introduction to the ideas and application of colored quarks in nuclear physics, color, the Pauli principle, and spin flavor correlations -- this lecture shows how the magnetic moments of hadrons relate to the underlying color degree of freedom, and the proton's spin -- a quark model perspective. This lecture reviews recent excitement which has led some to claim that in deep inelastic polarized lepton scattering very little of the spin of a polarized proton is due to its quarks. This lecture discusses the distribution functions of quarks and gluons in nucleons and nuclei, and how knowledge of these is necessary before some quark-gluon plasma searches can be analyzed. 56 refs., 2 figs.
Kaczmarek, O
2005-01-01T23:59:59.000Z
We analyze the change in free energy, internal energy and entropy due to the presence of a heavy quark anti-quark pair in a QCD heat bath. The internal energies and entropies are introduced as intensive observables calculated through thermal derivatives of the QCD partition function containing additional static color sources. The quark anti-quark internal energy and, in particular, the entropy clearly signal the phase change from quark confinement below and deconfinement above the transition and both observables are introduced such that they survive the continuum limit. The intermediate and large distance behavior of the energies reflect string breaking and color screening phenomena. This is used to characterize the energies which are needed to dissolve heavy quarkonium states in a thermal medium. Our discussion supports recent findings which suggest that parts of the quarkonium systems may survive the phase transition and dissolve only at higher temperatures.
Starzinger, Jakob
2005-01-01T23:59:59.000Z
Syrakus im Jahre 1802. Mein Sommer 1805. Herausgegeben vonnach Syrakus und Mein Sommer 1805. Wien 2005 (im Druck).nach Syrakus und Mein Sommer 1805. Wien 2005 (im Druck).
Mühlemann, Oliver
Wiederholungsprüfungen Termine fürs HS 2013 und FS 2014 (im KSL unter Leistungskontrolle 2. Termin erfasst) Bachelor Chemie Bachelor Biochemie Grundstudium Pharmazie Master Chemie und Molekulare Biochemie (Büro S170) für Veranstaltungen aus der Biochemie (°), falls Sie einen Termin abmachen möchten
Studien-und Prfungsordnung der Universitt Stuttgart fr den Bachelorstudiengang Erneuerbare Energien
Reyle, Uwe
Prüfungsordnung für den Bachelorstudiengang Erneuerbare Energien beschlossen. Der Rektor der Universität Stuttgart Bachelorstudiengang Erneuerbare Energien beschreibt den Aufbau des Studiums und die Organisation der Prüfungen. Sie1 Studien- und Prüfungsordnung der Universität Stuttgart für den Bachelorstudiengang Erneuerbare
I II. MUSICA PRO PACE 1999: Das >Junge Frankreich< und die
Steinhoff, Heinz-Jürgen
Kriegsniederlage 1940: André Jolivets »Les Trois Complaintes du Soldat« und Olivier Messiaens »Quatuor pour la Fin und Empfindungen der folgenden beiden Monate haben sich in Jolivets Les Trois Complaintes du Soldat
HUNTING THE QUARK GLUON PLASMA.
LUDLAM, T.; ARONSON, S.
2005-04-11T23:59:59.000Z
The U.S. Department of Energy's Relativistic Heavy Ion Collider (RHIC) construction project was completed at BNL in 1999, with the first data-taking runs in the summer of 2000. Since then the early measurements at RHIC have yielded a wealth of data, from four independent detectors, each with its international collaboration of scientists: BRAHMS, PHENIX, PHOBOS, and STAR [1]. For the first time, collisions of heavy nuclei have been carried out at colliding-beam energies that have previously been accessible only for high-energy physics experiments with collisions of ''elementary'' particles such as protons and electrons. It is at these high energies that the predictions of quantum chromodynamics (QCD), the fundamental theory that describes the role of quarks and gluons in nuclear matter, come into play, and new phenomena are sought that may illuminate our view of the basic structure of matter on the sub-atomic scale, with important implications for the origins of matter on the cosmic scale. The RHIC experiments have recorded data from collisions of gold nuclei at the highest energies ever achieved in man-made particle accelerators. These collisions, of which hundreds of millions have now been examined, result in final states of unprecedented complexity, with thousands of produced particles radiating from the nuclear collision. All four of the RHIC experiments have moved quickly to analyze these data, and have begun to understand the phenomena that unfold from the moment of collision as these particles are produced. In order to provide benchmarks of simpler interactions against which to compare the gold-gold collisions, the experiments have gathered comparable samples of data from collisions of a very light nucleus (deuterium) with gold nuclei, as well as proton-proton collisions, all with identical beam energies and experimental apparatus. The early measurements have revealed compelling evidence for the existence of a new form of nuclear matter at extremely high density and temperature--a medium in which the predictions of QCD can be tested, and new phenomena explored, under conditions where the relevant degrees of freedom, over nuclear volumes, are expected to be those of quarks and gluons, rather than of hadrons. This is the realm of the quark gluon plasma, the predicted state of matter whose existence and properties are now being explored by the RHIC experiments.
Couragiert und erfolgreich ,,Women of TUM" im TUM Netzwerk >> S. 1625
Heiz, Ulrich
, Landnutzung und Umwelt (WZW) der TUM wieder mit eigenem Stand auf dem Zentral-Landwirtschaftsfest, das alle
Messner, R. [Stanford Univ., CA (United States)
1997-01-01T23:59:59.000Z
This report covers preliminary measurements from SLD on heavy quark production at the Z{sup 0}, using 150,000 hadronic Z{sup 0} decays accumulated during the 1993-1995 runs. A measurement of R{sub b} with a lifetime double tag is presented. The high electron beam polarization of the SLC is employed in the direct measurement of the parity-violating parameters A{sub b} and A{sub c} by use of the left-right forward-backward asymmetry. The lifetimes of B{sup +} and B{sup 0} mesons have been measured by two analyses. The first identifies semileptonic decays of B mesons with high (p,p{sub t}) leptons; the second analysis isolates a sample of B meson decays with a two-dimensional impact parameter tag and reconstructs the decay length and charge using a topological vertex reconstruction method.
Top Quark Pair Production in Early CMS Data
Kao, Shih-Chuan
2011-01-01T23:59:59.000Z
23 2.13 top decay . . . . . . . . . . . . .of the Top Quark . . . . . . . . . . . . . . . . . . . . .20 Top Production in Hadron
Top Quark Physics at the ILC: Methods and Meanings
Zack Sullivan
2009-03-06T23:59:59.000Z
The physics case for studying top-quark physics at the International Linear Collider is well established. This summary places in context the top-quark physics goals, examines the current state-of-the art in understanding of the top-quark mass, and identifies some areas in which the study of the top-quark mass enhances our understanding of new techniques.
Singlet Free Energies of a Static Quark-Antiquark Pair
Konstantin Petrov
2004-09-01T23:59:59.000Z
We study the singlet part of the free energy of a static quark anti-quark pair at finite temperature in three flavor QCD with degenerate quark masses using $N_{\\tau}=4$ and 6 lattices with Asqtad staggered fermion action. We look at thermodynamics of the system around phase transition and study its scaling with lattice spacing and quark masses.
Search for Fourth Generation Quarks at CMS
Michael M. H. Luk
2011-10-26T23:59:59.000Z
We summarise the analyses that search for fourth generation quarks at the Central Muon Solenoid (CMS) experiment. Such particles provide a natural extension to the Standard Model (SM) and are still consistent with precision electroweak measurements. Our searches are not limited to fourth generation chiral quarks and are relevant to many Beyond the Standard Model theories. No excess over the expected SM background is observed in any of these analyses and limits are set on the masses of the $b^\\prime$ and $t^\\prime$ quarks at 95% confidence level at 361 GeV/$c^2$ and 450 GeV/$c^2$, respectively.
A. M. Green; C. Michael; J. E. Paton
1992-09-15T23:59:59.000Z
Four-quark potentials for $SU(2)$ are evaluated in the static limit with the quenched approximation -- using a lattice of $16^3\\times 32$ and $\\beta=2.4$. The four quarks are restricted to the corners of rectangles with sides upto seven lattice spacings long. The results are analysed in terms of a strategy based on interquark two-body potentials -- as advocated earlier by the authors. This shows that a standard two-body approach overestimates the four-quark binding energy by upto a factor of about three for the largest rectangles.
Quarks and gluons in hadrons and nuclei
Close, F.E. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA))
1989-01-01T23:59:59.000Z
These lectures discuss the particle-nuclear interface -- a general introduction to the ideas and application of colored quarks in nuclear physics, color, the Pauli principle, and spin flavor correlations -- this lecture shows how the magnetic moments of hadrons relate to the underlying color degree of freedom, and the proton's spin -- a quark model perspective. This lecture reviews recent excitement which has led some to claim that in deep inelastic polarized lepton scattering very little of the spin of a polarized proton is due to its quarks. 38 refs.
Top Quark Forward-Backward Asymmetry
Kingman Cheung; Wai-Yee Keung; Tzu-Chiang Yuan
2009-11-17T23:59:59.000Z
The recent forward-backward asymmetry recorded by the CDF Collaboration for the top and anti-top quark pair production indicates more than $2\\sigma$ deviation from the Standard Model prediction, while its total production cross section remains consistent. We propose a $W'$ boson that couples to down and top quarks. We identify the parameter space that can give rise a large enough forward-backward asymmetry without producing too many top and anti-top quark pairs. Other models presented erstwhile in the literature that can produce such effects are also discussed.
Paderborn, Universität
MICRO GRID angeschlossenen elektrischen Energiespeicher und eine ,,POWER TO GAS" -Anlage kompensiert
Static strings in Randall-Sundrum scenarios and the quark anti-quark potential: Erratum
Henrique Boschi-Filho; Nelson R. F. Braga; Cristine N. Ferreira
2006-10-11T23:59:59.000Z
We correct the energy of the static strings in hep-th/0512295, for large quark anti-quark separation. This energy is a smooth function of the quark separation for any position of the infrared brane. The asymptotic behavior of this energy is that of the Cornell potential as stated in the article. However, this identification does not fixes the AdS radius.
Heavy Quark Anti-Quark Free Energy and the Renormalized Polyakov Loop
Kaczmarek, O; Petreczky, P; Zantow, F
2002-01-01T23:59:59.000Z
We calculate the colour averaged and colour singlet free energies of static quark anti-quark sources placed in a thermal gluonic heat bath. We discuss the renormalization of these free energies using the short distance properties of the zero temperature heavy quark potential. This leads to the definition of the renormalized Polyakov loop as an order parameter for the deconfinement phase transition of the SU(3) gauge theory which is well behaved in the continuum limit.
Quenched hadron spectroscopy with improved staggered quark action
MILC Collaboration; Claude Bernard; Tom Blum; Thomas A. DeGrand; Carleton DeTar; Steven Gottlieb; Urs M. Heller; James Hetrick; Craig McNeile; K. Rummukainen; Bob Sugar; Doug Toussaint
1997-12-11T23:59:59.000Z
We investigate light hadron spectroscopy with an improved quenched staggered quark action. We compare the results obtained with an improved gauge plus an improved quark action, an improved gauge plus standard quark action, and the standard gauge plus standard quark action. Most of the improvement in the spectroscopy results is due to the improved gauge sector. However, the improved quark action substantially reduces violations of Lorentz invariance, as evidenced by the meson dispersion relations.
Recent Results of Top Quark Physics from the Tevatron
R. Y. Peters; on behalf of the D0; CDF collaborations
2015-07-09T23:59:59.000Z
Twenty years after its discovery in 1995 by the CDF and D0 collaborations at the Tevatron proton-antiproton collider at Fermilab, the top quark still undergoes intensive studies at the Tevatron and the LHC at CERN. In this article, recent top quark physics results from CDF and D0 are reported. In particular, measurements of single top quark and double top quark production, the ttbar forward-backward asymmetry and the top quark mass are discussed.
Theory of top quark production and decay
Kuehn, J.H. [Universitaet Karlsruhe (Germany)
1997-01-01T23:59:59.000Z
Direct and indirect information on the top quark mass and its decay modes is reviewed. The theory of top production in hadron- and electron-positron-colliders is presented.
Commissioning ATLAS and CMS with top quarks
B. S. Acharya; F. Cavallari; G. Corcella; R. Di Sipio; G. Petrucciani
2008-05-25T23:59:59.000Z
The large ttbar production cross-section at the LHC suggests the use of top quark decays to calibrate several critical parts of the detectors, such as the trigger system, the jet energy scale and b-tagging.
Kong, Kyoungchul; Lee, Hye-Sung; Park, Myeonghun
2014-04-01T23:59:59.000Z
We suggest top quark decays as a venue to search for light dark force carriers. The top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6sigma deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t-->bW+Z's. This is the same as the dominant top quark decay (t-->bW) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.
Collider signature of T-quarks
Carena, Marcela; Hubisz, Jay; /Fermilab; Perelstein, Maxim; /Cornell U., LEPP; Verdier, Patrice; /Lyon, IPN
2006-10-01T23:59:59.000Z
Little Higgs models with T Parity contain new vector-like fermions, the T-odd quarks or ''T-quarks'', which can be produced at hadron colliders with a QCD-strength cross section. Events with two acoplanar jets and large missing transverse energy provide a simple signature of T-quark production. We show that searches for this signature with the Tevatron Run II data can probe a significant part of the Little Higgs model parameter space not accessible to previous experiments, exploring T-quark masses up to about 400 GeV. This reach covers parts of the parameter space where the lightest T-odd particle can account for the observed dark matter relic abundance. We also comment on the prospects for this search at the Large Hadron Collider (LHC).
Evidence for production of single top quarks
Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Simon Fraser U.; Ahn, S.H.; /Korea U., KODEL; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP /Michigan U.
2008-03-01T23:59:59.000Z
We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p{bar p} collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top quark partner that is always produced from strong coupling processes. Top quarks were first observed in pair production in 1995, and since then, single top quark production has been searched for in ever larger datasets. In this analysis, we select events from a 0.9 fb{sup -1} dataset that have an electron or muon and missing transverse energy from the decay of a W boson from the top quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and t{bar t} events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top quark production of {sigma}(p{bar p} {yields} tb + X, tqb + X) = 4.7 {+-} 1.3 pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top quark production. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa quark mixing matrix element that describes the Wtb coupling and find |V{sub tb}f{sub 1}{sup L}| = 1.31{sub -0.21}{sup +0.25}, where f{sub 1}{sup L} is a generic vector coupling. This model-independent measurement translates into 0.68 < |V{sub tb}| {le} 1 at the 95% C.L. in the standard model.
Shear viscosity of the quark matter
Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome
2007-05-14T23:59:59.000Z
We discuss shear viscosity of the quark matter by using Kubo formula. The shear viscosity is calculated in the framework of the quasi-particle RPA for the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. The magnitude of the shear viscosity is discussed assuming the Breit-Wigner type for the spectral function.
Running heavy-quark masses in DIS
S. Alekhin; S. -O. Moch
2011-07-03T23:59:59.000Z
We report on determinations of the running mass for charm quarks from deep-inelastic scattering reactions. The method provides complementary information on this fundamental parameter from hadronic processes with space-like kinematics. The obtained values are consistent with but systematically lower than the world average as published by the PDG. We also address the consequences of the running mass scheme for heavy-quark parton distributions in global fits to deep-inelastic scattering data.
Charmonium with three flavors of synamical quarks
Massimo Di Pierro et al.
2003-12-23T23:59:59.000Z
We present a calculation of the charmonium spectrum with three flavors of dynamical staggered quarks from gauge configurations that were generated by the MILC collaboration. We use the Fermilab action for the valence charm quarks. Our calculation of the spin-averaged 1P-1S and 2S-1S splittings yields a determination of the strong coupling, with {alpha}{sub {ovr MS}}(M{sub Z}) = 0.119(4).
Heavy-light quarks interactions in QCD vacuum
Mirzayusuf Musakhanov
2015-03-20T23:59:59.000Z
QCD vacuum instantons induce very strong interactions between light quarks, which generate large dynamical light quark mass M for initially almost massless quarks and can bound these quarks to produce almost massless pions in accordance with the spontaneous breaking of chiral symmetry (S\\chiSB). On the other hand, the QCD vacuum instantons generate heavy-light quark interactions terms, which are responsible for the effects of S\\chiSB in a heavy-light quark system. Summing the re-scattering series that lead to the total light quark propagator and making few further steps, we get the fermionized representation of low-frequencies light quark determinant in the presence of the quark sources, which is relevant for our problems. The next important step in the line of this strategy is to derive the equation and calculate the heavy quark propagator in the instanton media and in the presence of light quarks. This one provide finally the heavy and N_f light quarks interaction term. As an example, we derive heavy quark-light mesons interaction term for the N_f=2 case. If we take the average instanton size \\rho=0.35 fm, and average inter-instanton distance R=0.856 fm from our previous estimates, we obtain at LO on 1/N_c expansion dynamical light quark mass M = 570 MeV and instanton media contribution to heavy quark mass \\Delta M=148 MeV. These factors define the coupling between heavy and light quarks and, certainly, between heavy quarks and light mesons. We will apply this approach to heavy quark and heavy-light quark systems.
Leonard S. Kisslinger; Debasish Das
2015-05-12T23:59:59.000Z
This is a review of the Quantum Chrodynamics Cosmological Phase Transition, the Quark-Gluon Plasma, and the detection of the Quark-Gluon Plasma via RHIC(Relativistic Heavy Ion Collisions) production of heavy quark states using the mixed hybrid theory for the $\\Psi(2S)$ and $\\Upsilon(3S)$ states.
Production, elliptic flow and energy loss of heavy quarks in the quark-gluon plasma
Jan Uphoff; Oliver Fochler; Zhe Xu; Carsten Greiner
2010-11-10T23:59:59.000Z
Production, elliptic flow and the nuclear modification factor of charm and bottom quarks are studied in central and non-central heavy-ion collisions at RHIC and LHC using the partonic transport model Boltzmann Approach of MultiParton Scatterings (BAMPS). Employing an initial heavy quark yield obtained with PYTHIA the full space-time evolution of charm and bottom quarks in the quark-gluon plasma (QGP) is carried out with BAMPS, taking also secondary production in the QGP into account. Only elastic collisions of heavy quarks with particles from the medium cannot describe the experimentally observed elliptic flow and nuclear modification factor. However, using an improved Debye screening and the running coupling yields a result which is much closer to data.
Measurements of top quark properties at the Tevatron collider
Margaroli, Fabrizio
2011-05-01T23:59:59.000Z
The discovery of the top quark in 1995 opened a whole new sector of investigation of the Standard Model; today top quark physics remains a key priority of the Tevatron program. Some of the measurements of top quark properties, for example its mass, will be a long-standing legacy. The recent evidence of an anomalously large charge asymmetry in top quark events suggests that new physics could couple preferably with top quarks. I will summarize this long chapter of particle physics history and discuss the road the top quark is highlighting for the LHC program.
Universal Mass Texture, CP violation and Quark-Lepton Complementarity
Canales, F Gonzalez; Barranco, J
2010-01-01T23:59:59.000Z
Recent measurements of the neutrino and quark mixing angles satisfy the empirical relations called quark-lepton complementarity. These empirical relations suggests the existence of a correlation between the mixing matrices of leptons and quarks. In this work, we examine the possibility that this correlation between the mixing angles of quarks and leptons originates in the similar hierarchy of quarks and charged lepton masses and the seesaw mechanism type I, that gives mass to the Majorana neutrinos. We asssume that the similar mass hierarchies of charged lepton and quark masses allows us to represent all the mass matrices of Dirac fermions in terms of a two zeroes Fritzsch texture.
Universal mass matrix for quarks and leptons and CP violation
Barranco, J.; Gonzalez Canales, F.; Mondragon, A. [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Am Muehlenberg 1, D-14476 Golm (Germany); Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510, Mexico D.F. (Mexico)
2010-10-01T23:59:59.000Z
The measurements of the neutrino and quark mixing angles satisfy the empirical relations called quark-lepton complementarity. These empirical relations suggest the existence of a correlation between the mixing matrices of leptons and quarks. In this work, we examine the possibility that this correlation between the mixing angles of quarks and leptons originates in the similar hierarchy of quarks and charged lepton masses and the seesaw mechanism type I, that gives mass to the Majorana neutrinos. We assume that the similar mass hierarchies of charged lepton and quark masses allows us to represent all the mass matrices of Dirac fermions in terms of a universal form with four texture zeroes.
STRUKTUR UND HERKUNFT DER WILDBIENEN-POPULATIONEN AUF FELDERN
Paris-Sud XI, Université de
STRUKTUR UND HERKUNFT DER WILDBIENEN-POPULATIONEN AUF FELDERN DER ZOTTELWICKE IN UNGARN. EIN, Budapest / Ungarn 2 SUMMARY STRUCTURE AND ORIGIN OF HAIRY VETCH POLLINATING WILD BEE POPULATIONS IN HUNGARY- wiesen, die in bestimmten Gebieten Ungarns die Zottelwicke bestäuben. Wegen der übergrossen Häufigkeit
4. Mit Charakterstarke und Integritat ubernommene Verantwortung im "Dritten Reich"
Alsmeyer, Gerold
Wahlgang (gegen Adolf Hitler und Ernst Th¨almann) erfolgte Wiederwahl er sich sehr stark engagiert hatte am 17. November 1932 zur¨uck. Nach ergebnislosen Verhandlungen mit Hitler wurde Schleicher am 3. De seinem R¨ucken verhandelte je- doch Papen am 22. Januar 1933 im Auftrage Hindenburgs mit Hitler ¨uber
University of North Dakota UND.edu/registrar
Delene, David J.
Calendar Page iv University Information Pages 1-25 Information Sources About UND Page 26 Undergraduate interested persons with information about their institution. Information contained in such printed material Academic Information Pages 27-217 (see table of contents for this section, page 27) Graduate Academic
INSTITUT FR ASIEN-UND AFRIKAWISSENSCHAFTEN ZENTRALASIEN-SEMINAR
Peters, Achim
INSTITUT FÜR ASIEN- UND AFRIKAWISSENSCHAFTEN ZENTRALASIEN-SEMINAR Kyrgyzstan today Youth services for women, migrants and youth in Kyrgyzstan Bolotkan Sydykanov Due to lack of information, education and financial resources, young women in the rural areas of Kyrgyzstan do not properly use health
Diplomanden-und Doktorandenseminar des Instituts fr Informatik
Zachmann, Gabriel
Diplomanden- und Doktorandenseminar des Instituts fÃ¼r Informatik Six Sigma im Im Ã¼blichen Sinne wird Six Sigma insbesondere in Fertigungsindustrien wie zum Beispiel in der ist Six Sigma nicht nur eine Managementstrategie, die sich ausschlieÃ?lich auf die Fertigungsindustrie
FE-Analysen zur Thermoermdung Test-und Feldzyklen
Berlin,Technische Universität
LIVE AG 1 -AG 2 FE-Analysen zur Thermoermüdung Test- und Feldzyklen R. Dudek, R. Döring, B #12;LIVE different SAC creep laws: Steady State Creep (after Schubert, SAC405 and Röllig/Wiese SAC xx) Creep properties of SAC 407 show much higher creep resistance than SAC xx SAC 305 bulk averaged values
Forschung und EU-Hochschulbro, Technologietransfer September 2014
Nejdl, Wolfgang
Nachwuchswissenschaftler/innen 4 1.2. LEIT: Information and communication technologies 4 1.2.1. Öffentliche Konsultation zu Programme Chemical Biology of Native Nucleic Acid Modifications (SPP 1784) 13 4.1.4. Volkswagen.1.8. NIH: Research Grants 16 5. Umweltwissenschaften und Energie 16 5.1.1. EU/KIC InnoEnergy: Call
Macht Musizieren gesund? Zur Herzrate und deren Variabilitt
Widmer, Gerhard
in Sankt Florian im Sommer 2008 in Ã?sterreich wurden die Herzraten von Klaus Laczika (Pianist und Mediziner Nachhinein nur die Herzdaten fÃ¼r die Auswertung verwendet werden. 1.Klaus Laczika, Klavier 2.Kirill Kobatschenko Violine 3.RenÃ© Staar, Violine 4.Arkadij Winokurov, Violine 5.Fritz Bauer, Viola 6.Erich Kaufmann
Bachelor's Thesis Hotfile-und Flaschenhals-Erkennung im
Wardetzky, Max
of those resources is dCache, a mass-storage management system partic- ularly developed for high energy relies on the deployment of efficient and reliable monitoring systems and optimisation techniques. OneBachelor's Thesis Hotfile- und Flaschenhals-Erkennung im dCache-System Hotfile and Bottleneck
Diplomanden-und Doktorandenseminar des Instituts fr Informatik
Zachmann, Gabriel
Datenkommunikation eines Remote Expert Maintenance Systems in der Instandhaltung der Volkswagen AG Braunschweig Abasin Gardiwal, TU Clausthal In größeren Unternehmen in der Industrie, wie z.B. bei der Volkswagen AG setzen. Hierdurch entstehen für die Volkswagen AG enorm hohe Kosten wie An- und Abfahrtskosten des
Statistik und Numerik Vorlesung Prof. Dr. Jens Timmer
Timmer, Jens
. Verrausche die dazugeh¨origen y-Werte mit N(0,2) mit = 0.1. Erstelle eine Matlab-Funktion modelfunction¨ussen in Matlab jeweils in eigenen Dateien mit der Endung .m abgespei- chert werden. Diese Dateien beginnen immer und ^k ausgeben. Schreibe eine Matlab-Funktion leastsquares, die als erstes Ausgabeargument den Vektor
Fakultat fur Physik und Astronomie Ruprecht-Karls-Universitat Heidelberg
Aeschbach-Hertig, Werner
wurden Bodenluftmessungen f¨ur die an der Zehrung beteiligten Gase O2, CO2, CH4 und H2S an zwei permanent and H2S involved in oxygen depletion were performed at two permanent sampling sites in Stuttgart process of relative noble gas enrichment in soil air due to the partial removal of gaseous CO2 produced
Color superconductivity and dense quark matter
Massimo Mannarelli
2008-12-26T23:59:59.000Z
The properties of cold and dense quark matter have been the subject of extensive investigation, especially in the last decade. Unfortunately, we still lack of a complete understanding of the properties of matter in these conditions. One possibility is that quark matter is in a color superconducting phase which is characterized by the formation of a diquark condensate. We review some of the basic concepts of color superconductivity and some of the aspects of this phase of matter which are relevant for compact stars. Since quarks have color, flavor as well as spin degrees of freedom many different color superconducting phases can be realized. At asymptotic densities QCD predicts that the color flavor locked phase is favored. At lower densities where the QCD coupling constant is large, perturbative methods cannot be applied and one has to rely on some effective model, eventually trying to constrain such a model with experimental observations. The picture is complicated by the requirement that matter in the interior of compact stars is in weak equilibrium and neutral. These conditions and the (possible) large value of the strange quark mass conspire to separate the Fermi momenta of quarks with different flavors, rendering homogenous superconducting phases unstable. One of the aims of this presentation is to introduce non-experts in the field to some of the basic ideas of color superconductivity and to some of its open problems.
The heavy top quark and supersymmetry
Hall, L.J. [Lawrence Berkeley Lab., CA (United States); [Univ. of California, Berkeley, CA (United States)
1997-01-01T23:59:59.000Z
Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the Standard Model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top quark; an extension of isospin provides a constrained framework for understanding the pattern of quark and lepton masses; and a grand unified extension of the Standard Model gauge group provides an elegant understanding of the gauge quantum numbers of the components of a generation. Experimental signatures for each of these additional symmetries are discussed.
Short distance physics with heavy quark potentials
Zantow, F; Karsch, Frithjof; Petreczky, P
2002-01-01T23:59:59.000Z
We present lattice studies of heavy quark potentials in the quenched approximation of QCD at finite temperatures. Both, the color singlet and color averaged potentials are calculated. While the potentials are well known at large distances, we give a detailed analysis of their short distance behavior (from 0.015 fm to 1 fm) near the critical temperature. At these distances we expect that the T-dependent potentials go over into the zero temperature potential. Indeed, we find evidences that the temperature influence gets suppressed and the potentials starts to become a unique function of the underlying distance scale. We use this feature to normalize the heavy quark potentials at short distances and extract the free energy of the quark system in a gluonic heat bath.
Physics Beyond the Single Top Quark Observation
Heinson, A.P.; Collaboration, for the DZero
2010-10-01T23:59:59.000Z
In March 2009, the D0 Collaboration first observed the electroweak production of single top quarks at 5{sigma} significance. We measured the cross section for the combined s-channel and t-channel production modes, and set a lower limit on the CKM matrix element |V{sub tb}|. Since then, we have used the same dataset to measure the t-channel production mode independently, the combined cross section in the hadronically-decaying tau lepton final state, and the width and lifetime of the top quark, and we have set upper limits on contributions from anomalous flavor-changing neutral currents. This paper describes these new measurements, as presented at the 3rd International Workshop on Top Quark Physics, held in Brugge, Belgium, May 31-June 4, 2010.
Lattice QCD Thermodynamics with Physical Quark Masses
R. A. Soltz; C. DeTar; F. Karsch; Swagato Mukherjee; P. Vranas
2015-02-08T23:59:59.000Z
Over the past few years new physics methods and algorithms as well as the latest supercomputers have enabled the study of the QCD thermodynamic phase transition using lattice gauge theory numerical simulations with unprecedented control over systematic errors. This is largely a consequence of the ability to perform continuum extrapolations with physical quark masses. Here we review recent progress in lattice QCD thermodynamics, focussing mainly on results that benefit from the use of physical quark masses: the crossover temperature, the equation of state, and fluctuations of the quark number susceptibilities. In addition, we place a special emphasis on calculations that are directly relevant to the study of relativistic heavy ion collisions at RHIC and the LHC.
Bulk viscosity in nuclear and quark matter: A short review
Hui Dong; Nan Su; Qun Wang
2007-03-05T23:59:59.000Z
The history and recent progresses in the study of bulk viscosity in nuclear and quark matter are reviewed. The constraints from baryon number conservation and electric neutrality in quark matter on particle densities and fluid velocity divergences are discussed.
Effect of thermalized charm on heavy quark energy loss
Souvik Priyam Adhya; Mahatsab Mandal; Sreemoyee Sarkar; Pradip K. Roy; Sukalyan Chattopadhyay
2014-08-28T23:59:59.000Z
The recent experimental results on the flow of $J/\\psi$ at LHC show that ample amount of charm quarks is present in the quark gluon plasma and probably they are thermalized. In the current study we investigate the effect of thermalized charm quarks on the heavy quark energy loss to leading order in the QCD coupling constant. It is seen that the energy loss of charm quark increases considerably due to the inclusion of thermal charm quarks. Running coupling has also been implemented to study heavy quark energy loss and we find substantial increase in the heavy quark energy loss due to heavy-heavy scattering at higher temperature to be realized at LHC energies.
New lattice action for heavy quarks
Oktay, Mehmet B.; Kronfeld, Andreas S. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States) and School of Mathematics, Trinity College, Dublin 2 (Ireland); Theoretical Physics Department, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)
2008-07-01T23:59:59.000Z
We extend the Fermilab method for heavy quarks to include interactions of dimensions 6 and 7 in the action. There are, in general, many new interactions, but we carry out the calculations needed to match the lattice action to continuum QCD at the tree level, finding six nonzero couplings. Using the heavy-quark theory of cutoff effects, we estimate how large the remaining discretization errors are. We find that our tree-level matching, augmented with one-loop matching of the dimension-5 interactions, can bring these errors below 1%, at currently available lattice spacings.
Joint resummation for heavy quark production.
Banfi, Andrea; Laenen, Eric
ar X iv :h ep -p h/ 05 10 14 9v 1 1 2 O ct 2 00 5 February 2, 2008 4:14 WSPC/INSTRUCTION FILE jr International Journal of Modern Physics A c© World Scientific Publishing Company JOINT RESUMMATION FOR HEAVY QUARK PRODUCTION ANDREA BANFI Cavendish... hadroproduction, at next-to-leading logarithmic accuracy. We exhibit their dependence on the production channel and the color configurations, and compare these distributions to eachother and to NLO. Keywords: Resummation; heavy quark production. 1. Joint threshold...
Top Quark Mass Measurements at the Tevatron
Zhenyu Ye; for CDF; D0 collaborations
2011-07-22T23:59:59.000Z
We report the latest results on the top-quark mass and on the top-antitop mass difference from the CDF and D0 collaborations using data collected at the Fermilab Tevatron $p\\bar{p}$ collider at $\\sqrt{s}=1.96$ TeV. We discuss general issues in top-quark mass measurements and present new results from direct measurements and from top-pair production cross-section. We also report new results on the top-antitop mass difference.
Top Quark Mass Measurements at the Tevatron
Ye, Zhenyu; /Fermilab
2011-07-01T23:59:59.000Z
We report the latest results on the top-quark mass and on the top-antitop mass difference from the CDF and D0 collaborations using data collected at the Fermilab Tevatron p{bar p} collider at {radical}s = 1.96 TeV. We discuss general issues in top-quark mass measurements and present new results from direct measurements and from top-pair production cross-section. We also report new results on the top-antitop mass difference.
Quark mass thresholds in QCD thermodynamics
M. Laine; Y. Schroder
2006-05-05T23:59:59.000Z
We discuss radiative corrections to how quark mass thresholds are crossed, as a function of the temperature, in basic thermodynamic observables such as the pressure, the energy and entropy densities, and the heat capacity of high temperature QCD. The indication from leading order that the charm quark plays a visible role at surprisingly low temperatures, is confirmed. We also sketch a way to obtain phenomenological estimates relevant for generic expansion rate computations at temperatures between the QCD and electroweak scales, pointing out where improvements over the current knowledge are particularly welcome.
Jorgen D'hondt
2007-07-10T23:59:59.000Z
The Large Hadron Collider (LHC) is expected to provide proton-proton collisions at a centre-of-mass energy of 14 TeV, yielding millions of of top quark events. The top-physics potential of the two general purpose experiments, ATLAS and CMS, is discussed according to state-of-the-art simulation of both physics and detectors. An overview is given of the most important results with emphasis on the expected improvements in our understanding of physics connected to the top quark.
Heavy quark production from jet conversions in a quark-gluon plasma
Liu, W.; Fries, Rainer J.
2008-01-01T23:59:59.000Z
multiplied by a K factor. The heavy quarks can be produced from the annihilation process g + g? Q+ ?Q that converts a gluon jet and a thermal gluon to a pair of heavy quarks, and also through theCompton processesg(q)+Q? Q+ g(q) by transferring... averaging ?Y (p?)? for the elastic process Q+ g(q)? Q+ g(q) is defined in Refs. [11] and [17]. Using a fixed coupling constant ?s = 0.3 and masses mg = gT / ? 2 for thermal gluons and mq = gT / ? 6 for thermal quarks [18], we calculate the transport...
Light quark spectrum with improved gauge and fermion actions
MILC Collaboration; Claude Bernard; Tom DeGrand; Carleton DeTar; Steven Gottlieb; Urs M. Heller; Jim Hetrick; Craig McNeile; Kari Rummukainen; Bob Sugar; Doug Toussaint; Matthew Wingate
1997-11-08T23:59:59.000Z
We report on a study of the light quark spectrum using an improved gauge action and both Kogut-Susskind and Naik quark actions. We have studied six different lattice spacings, corresponding to plaquette couplings ranging from 6.8 to 7.9, with five to six quark masses per coupling. We compare the two quark actions in terms of the spectrum and restoration of flavor symmetry. We also compare these results with those from the conventional action.
Systems of two heavy quarks with effective field theories
Nora Brambilla
2006-09-22T23:59:59.000Z
I discuss results and applications of QCD nonrelativistic effective field theories for systems with two heavy quarks.
Review of recent top-quark LHC combinations
Giorgio Cortiana; on behalf of the ATLAS; CMS collaborations within the TOPLHCWG
2014-11-27T23:59:59.000Z
A review of recent combinations of top-quark measurements performed at the LHC, by the ATLAS and CMS collaborations, is provided. The typical uncertainty categorisations, and their assumed correlation patterns are presented, together with the results of the combinations of the top-quark pair and single top-quark production cross sections, the top-quark mass, as well as of the $W$ boson polarisation and the charge asymmetry in $t\\bar t$ events.
TOP QUARK PHYSICS AT THE NLC CARL R. SCHMIDT
Schmidt, Carl
TOP QUARK PHYSICS AT THE NLC CARL R. SCHMIDT Santa Cruz Institute for Particle Physics University) is an excellent tool for studying the properties of the top quark. In this talk I review some of the theory of top, is an ideal tool for studying the properties of the top quark. The event environment in e + e \\Gamma
Paris-Sud XI, Université de
477 Short term thermal energy storage A. Abhat Institut für Kernenergetik und Energiesysteme the problem of short term thermal energy storage for low temperature solar heating applications
Heavy quark collisional energy loss in the quark-gluon plasma including finite relaxation time
Mauro Elias; J. Peralta-Ramos; E. Calzetta
2014-07-12T23:59:59.000Z
In this paper, we calculate the soft-collisional energy loss of heavy quarks traversing the viscous quark-gluon plasma including the effects of a finite relaxation time $\\tau_\\pi$ on the energy loss. We find that the collisional energy loss depends appreciably on $\\tau_\\pi$ . In particular, for typical values of the viscosity-to-entropy ratio, we show that the energy loss obtained using $\\tau_\\pi$ = 0 can be $\\sim$ 10$\\%$ larger than the one obtained using $\\tau_\\pi$ = 0. Moreover, we find that the energy loss obtained using the kinetic theory expression for $\\tau_\\pi$ is much larger that the one obtained with the $\\tau_\\pi$ derived from the Anti de Sitter/Conformal Field Theory correspondence. Our results may be relevant in the modeling of heavy quark evolution through the quark-gluon plasma.
On static quark anti-quark potential at non-zero temperature
A. Bazavov; P. Petreczky
2012-10-23T23:59:59.000Z
We study Wilson loops at non-zero temperature and extract the static quark potential from them. The extracted potentials are larger than the singlet free energies and do not show screening for $T<190$ MeV.
Resonance recombination model and quark distribution functions in the quark-gluon plasma
Ravagli, L.; van Hees, H.; Rapp, Ralf.
2009-01-01T23:59:59.000Z
We investigate the consequences of space-momentum correlations in quark phase-space distributions for coalescence processes at the hadronization transition. Thus far it has been proved difficult to reconcile such correlations with the empirically...
Heavy-quark symmetry and chiral dynamics
Yan, T. (Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (Taiwan, Province of China) Floyd R. Newman Laboratory of Nuclear Studies, Cornell University, Ithaca, New York 14853 (United States)); Cheng, H.; Cheung, C.; Lin, G. (Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (Taiwan, Province of China)); Lin, Y.C. (Physics Department, National Central University, Chung-li, Taiwan 32054 (Taiwan, Province of China)); Yu, H. (Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (Taiwan, Province of China))
1992-08-01T23:59:59.000Z
The flavor and spin symmetry of the heavy quarks and the spontaneously broken approximate SU(3){sub {ital L}}{times} SU(3){sub {ital R}} chiral symmetry of the light quarks are exploited to formulate a theory describing the low-energy interactions of the heavy mesons ({ital Q{bar q}} bound states) and heavy baryons ({ital Qq}{sub 1}{ital q2} bound states) with the Goldstone bosons {pi}, {ital K}, and {eta}. The theory contains only three parameters independent of the number of heavy-quark species involved. They can be determined by the decays {ital D}{sup *}{r arrow}{ital D}+{pi}, {Sigma}{sub {ital c}}{r arrow}{Lambda}{sub {ital c}}+{pi}, and {Sigma}{sub {ital c}}{sup *}{r arrow}{Sigma}{sub {ital c}}+{pi}. Theoretically, these coupling constants are related, through partial conservation of axial-vector current, to the axial charges of the heavy mesons and the heavy baryons. They are all calculable in the nonrelativistic quark model by using the spin wave functions of these particles alone. The theory is applied to strong decays and semileptonic weak decays of the heavy mesons and baryons. The implications are also discussed.
Quark-Gluon Plasma: Present and Future
Tapan K. Nayak
2008-04-08T23:59:59.000Z
We review a sample of the experimental results from AGS to SPS and RHIC and their interpretations towards understanding of the Quark-Gluon Plasma. We discuss extrapolations of these results to the upcoming LHC experiments. Finally, we present the plans to probe the QCD critical point with an energy scan at RHIC and FAIR facilities.
Diquark and light four-quark states
Zhang Ailin [Department of Physics, Shanghai University, Shanghai, 200444 (China); Huang Tao [Institute of High Energy Physics, Chinese Academy of Science, P. O. Box 918 (4), Beijing, 100049 (China); Steele, Tom G. [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK, S7N 5E2 (Canada)
2007-08-01T23:59:59.000Z
Four-quark states with different internal clusters are discussed within the constituent quark model. It is pointed out that the diquark concept is not meaningful in the construction of a tetraquark interpolating current in the QCD sum-rule approach, and hence existing sum-rule studies of four-quark states are incomplete. An updated QCD sum-rule determination of the properties of diquark clusters is then used as input for the constituent quark model to obtain the masses of light 0{sup ++} tetraquark states (i.e. a bound state of two diquark clusters). The results support the identification of {sigma}(600), f{sub 0}(980), and a{sub 0}(980) as the 0{sup ++} light tetraquark states, and seem to be inconsistent with the tetraquark state interpretation of the new BES observations of the near-threshold pp enhancements, X(1835) and X(1812), with the possible exception that X(1576) may be an exotic first orbital excitation of f{sub 0}(980) or a{sub 0}(980)
Strange quark momentum fraction from overlap fermion
Mingyang Sun; Yi-Bo Yang; Keh-Fei Liu; Ming Gong
2015-03-10T23:59:59.000Z
We present a calculation of $_s$ for the strange quark in the nucleon. We also report the ratio of the strange $$ to that of $u/d$ in the disconnected insertion which will be useful in constraining the global fit of parton distribution functions at small $x$. We adopt overlap fermion action on $2 + 1$ flavor domain-wall fermion configurations on the $24^3 \\times 64$ lattice with a light sea quark mass which corresponds to $m_{\\pi}=330$ MeV. Smeared grid $Z_3$ sources are deployed to calculate the nucleon propagator with low-mode substitution. Even-odd grid sources and time-dilution technique with stochastic noises are used to calculate the high mode contribution to the quark loop. Low mode averaging (LMA) for the quark loop is applied to reduce the statistical error of the disconnected insertion calculation. We find the ratio $_s/_{u/d}^{\\mathrm{DI}}= 0.78(3)$ in this study.
Strange quark momentum fraction from overlap fermion
Sun, Mingyang; Liu, Keh-Fei; Gong, Ming
2015-01-01T23:59:59.000Z
We present a calculation of $\\langle x \\rangle_s$ for the strange quark in the nucleon. We also report the ratio of the strange $\\langle x \\rangle$ to that of $u/d$ in the disconnected insertion which will be useful in constraining the global fit of parton distribution functions at small $x$. We adopt overlap fermion action on $2 + 1$ flavor domain-wall fermion configurations on the $24^3 \\times 64$ lattice with a light sea quark mass which corresponds to $m_{\\pi}=330$ MeV. Smeared grid $Z_3$ sources are deployed to calculate the nucleon propagator with low-mode substitution. Even-odd grid sources and time-dilution technique with stochastic noises are used to calculate the high mode contribution to the quark loop. Low mode averaging (LMA) for the quark loop is applied to reduce the statistical error of the disconnected insertion calculation. We find the ratio $\\langle x \\rangle_s/\\langle x \\rangle_{u/d}^{\\mathrm{DI}}= 0.78(3)$ in this study.
Top quark property measurements at the LHC
Richard Hawkings
2014-10-29T23:59:59.000Z
Measurements of top quark properties performed at the Large Hadron Collider are reviewed, with a particular emphasis on top-pair charge asymmetries, spin correlations and polarization measurements performed by the ATLAS and CMS collaborations. The measurements are generally in good agreement with predictions from next-to-leading-order QCD calculations, and no deviations from Standard Model expectations have been seen.
Effective Field Theory for Top Quark Physics
Cen Zhang; Scott Willenbrock
2010-08-18T23:59:59.000Z
Physics beyond the standard model can affect top-quark physics indirectly. We describe the effective field theory approach to describing such physics, and contrast it with the vertex-function approach that has been pursued previously. We argue that the effective field theory approach has many fundamental advantages and is also simpler.
B-physics with dynamical domain-wall light quarks and relativistic b-quarks
Ruth S. Van de Water; Oliver Witzel
2011-01-24T23:59:59.000Z
We report on our progress in calculating the B-meson decay constants and B^0-bar B^0 mixing parameters using domain-wall light quarks and relativistic b-quarks. We present our computational method and show some preliminary results obtained on the coarser (a approx 0.11fm) 24^3 lattices. This work is presented on behalf of the RBC and UKQCD collaborations.
Fischlin, Andreas
Quellen durch Veränderungen in der Landnutzung vorhanden. Bis heute sind dies ungefähr 180-200 Pg C im) und der durch die Menschen weltweit emittierten Kohlenstoffmenge (Emissionen und Landnutzungs
Traditionelles Bauen und Wohnen der Salar in Nordwest-China
Wagner, Mayke; Flitsch, Mareile; Winterstein, Claudia; Lehmann, Heike; Heuß ner, Karl-Uwe; Ren, Xiaoyan; Xiao, Yongming; Cai, Linhai; Wulf-Rheidt, Ulrike; Tarasov, Pavel; Dwyer, Arienne M.
2007-01-01T23:59:59.000Z
aus. Allerdings war zu erkennen, dass viele neuere Bauten mit lokal verfügbaren Baustof fen wie Lehmziegeln oder in moderner Betonbau weise errichtet wurden. Unsere Beobachtungen war fen eine ganze Reihe von Fragen auf: Worin genau bestehen die.... Qinghai. Rechts Haupthaus an der Nordseite, links Westhaus (Foto MW) ABB. 5 Holzrahmenkonstruk tion eines chinesischen Hauses in Lajia, Prov. Qinghai (Foto MW) hingegen Wände einfach und günstig mit lokal ver fügbarem Baumaterial von Laien...
Top Quark Properties at the TeVatron
Yvonne Peters for the CDF; D0 Collaborations
2011-03-29T23:59:59.000Z
Discovered in 1995 by CDF and D0 at the Fermilab Tevatron collider, the top quark remains interesting to test the Standard Model. Having collected more than 7 fb$^{-1}$ of integrated luminosity with both experiments until today, several top quark properties have been measured with increasing precision, while other properties have been investigated for the first time. In this article recent measurements of top quark properties from CDF and D0 are presented, using between 1 fb$^{-1}$ and 4.8 fb$^{-1}$ of data. In particular, the measurement of the top quark mass, the top quark width, the top antitop mass difference, a check of the electric charge of the top quark, measurements of the top antitop quark spin correlation and W helicity as well as a search for charged Higgs bosons are discussed.
I. Bloch, DESY/Hamburg University - CIPANP, Puerto Rico 30.5.-03.06.'06 1Heavy Quarks at HERA Heavy, Puerto Rico 30.5.-03.06.'06 2Heavy Quarks at HERA HERA: ep collisions within H1 & ZEUS 920 GeV protons920/Hamburg University - CIPANP, Puerto Rico 30.5.-03.06.'06 3Heavy Quarks at HERA H1&ZEUS integrated Luminosity: 96
Entwicklung 1815 - 1945 K 83 Österreich und Preußen bis 1795 K 84 Die Teilung Polens 1772 - 1795 ; Polen im 20
Markert, C
2000-01-01T23:59:59.000Z
$\\Lambda$(1520)-Produktion in Proton-Proton- und zentralen Blei-Blei-Reaktionen bei 158 GeV pro Nukleon
C. G. Duan; N. Liu; G. L. Li
2008-11-05T23:59:59.000Z
By means of two different parametrizations of quark energy loss and the nuclear parton distributions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order phenomenological analysis is performed on the nuclear Drell-Yan differential cross section ratios as a function of the quark momentum fraction in the beam proton and target nuclei for E772 experimental data. It is shown that there is the quark energy loss effect in nuclear Drell-Yan process apart from the nuclear effects on the parton distribution as in deep inelastic scattering. The uncertainties due to quark energy loss effect is quantified on determining nuclear sea quark distribution by using nuclear Drell-Yan data. It is found that the quark energy loss effect on nuclear Drell-Yan cross section ratios make greater with the increase of quark momentum fraction in the target nuclei. The uncertainties from quark energy loss become bigger as the nucleus A come to be heavier. The Drell-Yan data on proton incident middle and heavy nuclei versus deuterium would result in an overestimate for nuclear modifications on sea quark distribution functions with neglecting the quark energy loss. Our results are hoped to provide good directional information on the magnitude and form of nuclear modifications on sea quark distribution functions by means of the nuclear Drell-Yan experimental data.
Static quark anti-quark free and internal energy in 2-flavor QCD and bound states in the QGP
O. Kaczmarek; F. Zantow
2005-10-21T23:59:59.000Z
We present results on heavy quark free energies in 2-flavour QCD. The temperature dependence of the interaction between static quark anti-quark pairs will be analyzed in terms of temperature dependent screening radii, which give a first estimate on the medium modification of (heavy quark) bound states in the quark gluon plasma. Comparing those radii to the (zero temperature) mean squared charge radii of cha rmonium states indicates that the $J/\\psi$ may survive the phase transition as a bound state, while $\\chi_c$ and $\\psi'$ are expected to show significant thermal modifications at temperatures close to the transition. Furthermore we will analyze the relation between heavy quark free energies, entropy contributions and internal energy and discuss their relation to potential models used to analyze the melting of heavy quark bound states above the deconfinement temperature. Results of different groups and various potential models for bound states in the deconfined phase of QCD are compared.
Radiative energy loss of high energy quarks in finite-size nuclear matter and quark-gluon plasma
B. G. Zakharov
1997-04-07T23:59:59.000Z
The induced gluon radiation of a high energy quark in a finite-size QCD medium is studied. For a sufficiently energetic quark produced inside a medium we find the radiative energy loss $\\Delta E_{q}\\propto L^{2}$, where L is the distance passed by quark in the medium. It has a weak dependence on the initial quark energy $E_{q}$. The $L^{2}$ dependence turns to $L^{1}$ as the quark energy decreases. Numerical calculations are performed for a cold nuclear matter and a hot quark-gluon plasma. For a quark incident on a nucleus we predict $\\Delta E_{q}\\approx 0.1 E_{q}(L/10 fm)^{\\beta}$, with $\\beta$ close to unity.
Free energies of heavy quarks in full-QCD lattice simulations with Wilson-type quark action
Y. Maezawa; S. Aoki; S. Ejiri; T. Hatsuda; N. Ishii; K. Kanaya; H. Ohno; T. Umeda
2009-09-16T23:59:59.000Z
The free energy between a static quark and an antiquark is studied by using the color-singlet Polyakov-line correlation at finite temperature in lattice QCD with 2+1 flavors of improved Wilson quarks. From the simulations on $32^3 \\times 12$, 10, 8, 6, 4 lattices in the high temperature phase, based on the fixed scale approach, we find that, the heavy-quark free energies at short distance converge to the heavy-quark potential evaluated from the Wilson loop at zero temperature, in accordance with the expected insensitivity of short distance physics to the temperature. At long distance, the heavy-quark free energies approach to twice the single-quark free energies, implying that the interaction between heavy quarks is screened. The Debye screening mass obtained from the long range behavior of the free energy is compared with the results of thermal perturbation theory.
Continuum Study of Heavy Quark Diffusion
Thomas Neuhaus
2015-04-28T23:59:59.000Z
We report on a lattice investigation of heavy quark momentum diffusion within the pure SU(3) plasma above the deconfinement transition with the quarks treated to leading order in the heavy mass expansion. We measure the relevant "colour-electric" Euclidean correlator and based on several lattice spacing's perform the continuum extrapolation. This is necessary not only to remove cut-off effects but also the analytic continuation for the extraction of transport coefficients is well-defined only when a continuous function of the Euclidean time variable is available. We pay specific attention to scale setting in SU(3). In particular we present our determination for the critical temperature $T_c=1/({N_\\tau}a) $ at values of $N_\\tau \\le 22$.
Collisional energy loss of a fast heavy quark in a quark-gluon plasma
Stephane Peigne; Andre Peshier
2008-02-29T23:59:59.000Z
We discuss the average collisional energy loss dE/dx of a heavy quark crossing a quark-gluon plasma, in the limit of high quark energy E >> M^2/T, where M is the quark mass and T >> M is the plasma temperature. In the fixed coupling approximation, at leading order dE/dx \\propto \\alpha_s^2, with a coefficient which is logarithmically enhanced. The soft logarithm arising from t-channel scattering off thermal partons is well-known, but a collinear logarithm from u-channel exchange had previously been overlooked. We also determine the constant beyond those leading logarithms. We then generalize our calculation of dE/dx to the case of running coupling. We estimate the remaining theoretical uncertainty of dE/dx, which turns out to be quite large under RHIC conditions. Finally, we point out an approximate relation between dE/dx and the QCD Debye mass, from which we derive an upper bound to dE/dx for all quark energies.
B-quark production at hadron colliders
Meng, Ruibin [Argonne National Lab., IL (United States); Riemersma, S. [Southern Methodist Univ., Dallas, TX (United States)
1993-08-01T23:59:59.000Z
Studying B-physics at hadron accelerators requires a good understanding of the total and differential cross sections for b-quark production. This knowledge gives those involved in B{bar B} mixing, rare B decays, and those trying to determine the CKM angles {alpha}, {beta}, and {gamma} an idea of how many events they can expect, given the luminosity and the branching ratios. It is particularly important for those studying rare B decays as they set limits on where we can hope to see new physics. For these reasons and others, the complete {Omicron}({alpha}{sub s}{sup 3}) corrections to heavy-quark production at hadron accelerators were calculated in. Also three groups have attempted to calculate heavy-quark production using resummation techniques in the small-x kinematic region. These resummation techniques are necessary since the b-quark mass m{sub b} is small relative to the center-of-mass energies {radical}S of the TeVatron and the SSC. While these techniques offer some hope of obtaining reasonable predictions for b-production at these machines, the current results can best be considered as preliminary. Thus we must turn to fixed-order perturbative QCD for guidance, as we have no other real choice at this point. However, let us submit a caveat here: fixed-order perturbative QCD works best when all the scales are roughly comparable, i.e. {radical}s {approx} m{sub b} {approx} p{sub t}, {radical}s being the partonic center-of-mass energy. When we are not in this regime, for example at the TeVatron and the SSC, our predictions will then be less reliable. Bearing this in mind, let use continue to the results section.
Middeldorp, Aart
Studienplan für die neue Studienrichtung ,,Informatik" an der Universität Innsbruck 532. Reform des. Reform des Studienplanes für ein Bakkalaureats- und Magister-Studium Kommunikationswissenschaft an der Universität Salzburg - Begutachtungsverfahren 534. Reform des Studienplanes für das Diplomstudium Architektur
Color superconducting quark matter in compact stars
D. B. Blaschke; T. Klahn; F. Sandin
2007-12-02T23:59:59.000Z
Recent indications for high neutron star masses (M \\sim 2 M_sun) and large radii (R > 12 km) could rule out soft equations of state and have provoked a debate whether the occurence of quark matter in compact stars can be excluded as well. We show that modern quantum field theoretical approaches to quark matter including color superconductivity and a vector meanfield allow a microscopic description of hybrid stars which fulfill the new, strong constraints. For these objects color superconductivity turns out to be an essential ingredient for a successful description of the cooling phenomenology in accordance with recently developed tests. We discuss the energy release in the neutrino untrapping transition as a new aspect of the problem that hybrid stars masquerade themselves as neutron stars. Quark matter searches in future generations of low-temperature/high-density nucleus-nucleus collision experiments such as low-energy RHIC and CBM @ FAIR might face the same problem of an almost crossover behavior of the deconfinement transition. Therefore, diagnostic tools shall be derived from effects of color superconductivity.
Shear Viscosity in a CFL Quark Star
Cristina Manuel; Antonio Dobado; Felipe J. Llanes-Estrada
2005-09-30T23:59:59.000Z
We compute the mean free path and shear viscosity in the color-flavor locked (CFL) phase of dense quark matter at low temperature T, when the contributions of mesons, quarks and gluons to the transport coefficients are Boltzmann suppressed. CFL quark matter displays superfluid properties, and transport phenomena in such cold regime are dominated by phonon-phonon scattering. We study superfluid phonons within thermal field theory and compute the mean free path associated to their most relevant collision processes. Small-angle processes turn out to be more efficient in slowing transport phenomena in the CFL matter, while the mean free path relevant for the shear viscosity is less sensitive to collinear scattering due to the presence of zero modes in the Boltzmann equation. In analogy with superfluid He4, we find the same T power law for the superfluid phonon damping rate and mean free path. Our results are relevant for the study of rotational properties of compact stars, and correct wrong estimates existing in the literature.
Top quark physics at the Tevatron
Antonio Sidoti
2004-03-17T23:59:59.000Z
After the successful Run I of the Tevatron (1992-1996),with the top quark discovery, both CDF and D0 experiments were extensively upgraded to meet the challenges of the Tevatron Run II collider. The energy of p{bar p} collisions at the Tevatron was increased from {radical}s = 1.8 TeV to {radical}s = 1.96 TeV. t{bar t} production cross section is expected to increase by a factor of {approx} 30%. Major upgrades in the Tevatron accelerator chain will increase the Run II instantaneous luminosity: the goal is to achieve L = 5 - 20 x 10{sup 31} cm{sup 2}s{sup -1} while the highest luminosity reached up to now (September 2003) is 5.2 x 10{sup 31} cm{sup 2} s{sup -1}. In this paper we will present the top quark properties measured by both CDF and D0 with the first physics-quality data collected during the Run II (March 2002-January 2003). First we will review t{bar t} cross section measurements in the various decay channels; then top quark mass measurements will be presented.
The Top Quark - 2006 and Beyond
John Womersley
2006-04-04T23:59:59.000Z
We know there is new physics at the electroweak scale, but we don't know what it is. Right now, the top quark is our only window on to this physics. In almost all models of electroweak symmetry breaking, top either couples strongly to new particles or its properties are modified in some way. Top is being studied in detail at the Fermilab Tevatron. Its production cross section has been measured in a variety of channels; its mass has been determined to better than 2%, and can be used to constrain the mass of the Higgs. Top quark decays have been tested and non-standard production mechanisms searched for. Single top production probes the electroweak properties of top, and has not yet been observed; searches are now closing in on this process and it should be seen soon. So far, all of the top quark's properties are consistent with the Standard Model. However, the data still to come at the Tevatron will increase the precision of all these measurements, and the enormous statistics available at the LHC will open up new possibilities such as observation of spin correlations and perhaps even CP violation in the top sector.
Quark Nova Model for Fast Radio Bursts
Zachary Shand; Amir Ouyed; Nico Koning; Rachid Ouyed
2015-05-29T23:59:59.000Z
FRBs are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via $\\beta$-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm$^{-3}$ pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of $\\beta$-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies ($\\sim$ 10$^{41}$ ergs), spectra shapes and provide a theoretical framework for determining distances.
Recent PQCD calculations of heavy quark production
Vitev, I
2006-01-01T23:59:59.000Z
We summarize the results of a recent study of heavy quark production and attenuation in cold nuclear matter. In p+p collisions, we investigate the relative contribution of partonic sub-processes to $D$ meson production and $D$ meson-triggered inclusive di-hadrons to lowest order in perturbative QCD. While gluon fusion dominates the creation of large angle $D\\bar{D}$ pairs, charm on light parton scattering determines the yield of single inclusive $D$ mesons. The distinctly different non-perturbative fragmentation of $c$ quarks into $D$ mesons versus the fragmentation of quarks and gluons into light hadrons results in a strong transverse momentum dependence of anticharm content of the away-side charm-triggered jet. In p+A reactions, we calculate and resum the coherent nuclear-enhanced power corrections from the final-state partonic scattering in the medium. We find that single and double inclusive open charm production can be suppressed as much as the yield of neutral pions from dynamical high-twist shadowing. ...
Top-quark mass measurements: Alternative techniques (LHC + Tevatron)
Stefanie Adomeit
2014-11-28T23:59:59.000Z
Measurements of the top-quark mass employing alternative techniques are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at the LHC. The alternative methods presented include measurements using the lifetime of $B$-hadrons, the transverse momentum of charged leptons and the endpoints of kinematic distributions in top quark anti-quark pair ($t\\bar{t}$) final states. The extraction of the top-quark pole mass from the $t\\bar{t}$ production cross-section and the normalized differential $t\\bar{t}$ + 1-jet cross-section are discussed as well as the top-quark mass extraction using fixed-order QCD predictions at detector level. Finally, a measurement of the top-quark mass using events enhanced in single top t-channel production is presented.
Static quark anti-quark pair in SU(2) gauge theory
A. Bazavov; P. Petreczky; A. Velytsky
2008-09-11T23:59:59.000Z
We study singlet and triplet correlation functions of static quark anti-quark pair defined through gauge invariant time-like Wilson loops and Polyakov loop correlators in finite temperature SU(2) gauge theory. We use the Luescher-Weisz multilevel algorithm, which allows to calculate these correlators at very low temperatures. We observe that the naive separation of singlet and triplet states in general does not hold non-perturbatively, however, is recovered in the limit of small separation and the temperature dependence of the corresponding correlators is indeed very different.
Top quark mass measurements at the D0 experiment
Alexander Grohsjean
2009-05-30T23:59:59.000Z
The most recent measurements of the top quark mass at the D0 experiment are summarized. Different techniques and final states are used and the top quark mass is determined to be mtop=172.8+-1.6(stat+syst)GeV/c^2. In addition, a new, indirect measurement comparing the measured cross section to theoretical calculations is discussed. Both, the direct and the indirect measurement of the top quark mass are in good agreement.
The Top Quark Forward Backward Asymmetry at CDF
Yen-Chu Chen for the CDF collaboration
2011-07-01T23:59:59.000Z
It has been more than 15 years since the discovery of the top quark. Great strides have been made in the measurement of the top quark mass and the properties of it. Most results show consistency with the standard model. However, using 5 fb$^{-1}$ data, recent measurements of the asymmetry in the production of top and anti-top quark pair have demonstrated surprisingly large values at CDF. Using 4 fb$^{-1}$ data, D0 also has similar effect.
Thermodynamics of QCD at large quark chemical potential
Andreas Gerhold; Andreas Ipp; Anton Rebhan
2005-12-21T23:59:59.000Z
We review the existing weak-coupling results on the thermodynamic potential of deconfined QCD at small and large quark chemical potential and compare with results from lattice gauge theory as well as the exactly solvable case of large-N_f QCD. We also discuss the new analytical results on non-Fermi-liquid effects in entropy and specific heat as well as in dispersion laws of quark quasiparticles at large quark chemical potential.
QCD Thermodynamics with an almost realistic quark mass spectrum
C. Schmidt
2006-01-25T23:59:59.000Z
We will report on the status of a new large scale calculation of thermodynamic quantities in QCD with light up and down quarks corresponding to an almost physical light quark mass value and a heavier strange quark mass. These calculations are currently being performed on the QCDOC Teraflops computers at BNL. We will present new lattice calculations of the transition temperature and various susceptibilities reflecting properties of the chiral transition. All these quantities are of immediate interest for heavy ion phenomenology.
Evolution equation for 3-quark Wilson loop operator
R. E. Gerasimov; A. V. Grabovsky
2012-12-07T23:59:59.000Z
The evolution equation for the 3 quark Wilson loop operator has been derived in the leading logarithm approximation within Balitsky high energy operator expansion.
Proposal to support junior scientists participation of Quark Matter 2004
Huan Zhong Huang; Kenneth Barish; Hans Georg Ritter
2005-12-15T23:59:59.000Z
This report summarizes the student and post-doc support budget for quark matter 2004 conference, held at Oakland in January 2004.
Dynamical electroweak symmetry breaking and the top quark
Chivukula, R.S. [Boston Univ., MA (United States)
1997-01-01T23:59:59.000Z
In this talk, I discuss theories of dynamical electroweak symmetry breaking, with emphasis on the implications of a heavy top quark on the weak interaction {rho} parameter.
Quark-Gluon Plasma: a New State of Matter
Brookhaven Lab
2010-01-08T23:59:59.000Z
Physicist Peter Steinberg explains the nature of the quark gluon plasma (QGP), a new state of matter produced at Brookhaven Lab's Relativistic Heavy Ion Collider (RHIC).
Light front approach to correlations in hot quark matter
S. Strauss; M. Beyer; S. Mattiello
2006-01-30T23:59:59.000Z
We investigate two-quark correlations in hot and dense quark matter. To this end we use the light front field theory extended to finite temperature $T$ and chemical potential $\\mu$. Therefore it is necessary to develop quantum statistics formulated on the light front plane. As a test case for light front quantization at finite $T$ and $\\mu$ we consider the NJL model. The solution of the in-medium gap equation leads to a constituent quark mass which depends on $T$ and $\\mu$. Two-quark systems are considered in the pionic and diquark channel. We compute the masses of the two-body system using a $T$-matrix approach.
Studies of top quark properties at the Tevatron
Shary, Viatcheslav
2012-05-01T23:59:59.000Z
An overview of the recent measurements of the top quark properties in proton antiproton collisions at {radical}s = 1.96 TeV is presented. These measurements are based on 5.4-8.7 fb{sup -1} of data collected with the D0 and CDF experiments at the Fermilab Tevatron collider. The top quark mass and width measurements, studies of the spin correlation in top quark pair production, W boson helicity measurement, searches for anomalous top quark couplings and Lorentz invariance violation are discussed.
Y. Maezawa; S. Aoki; S. Ejiri; T. Hatsuda; N. Ishii; K. Kanaya; N. Ukita; T. Umeda
2007-10-04T23:59:59.000Z
Thermodynamics of two-flavor QCD at finite temperature and density is studied on a $16^3 \\times 4$ lattice, using a renormalization group improved gauge action and the clover improved Wilson quark action. In the simulations along lines of constant $m_{\\rm PS}/m_{\\rm V}$, we calculate the Taylor expansion coefficients of the heavy-quark free energy with respect to the quark chemical potential ($\\mu_q$) up to the second order. By comparing the expansion coefficients of the free energies between quark($Q$)and antiquark($\\bar{Q}$), and between $Q$ and $Q$, we find a characteristic difference at finite $\\mu_q$ due to the first order coefficient of the Taylor expansion. We also calculate the quark number and isospin susceptibilities, and find that the second order coefficient of the quark number susceptibility shows enhancement around the pseudo-critical temperature.
Resonance recombination model and quark distribution functions in the quark-gluon plasma
Ravagli, L.; van Hees, H.; Rapp, Ralf.
2009-01-01T23:59:59.000Z
is adjusted to hydrodynamic simulations of semicentral Au-Au collisions at RHIC. To facilitate the applicability of the Langevin process, we focus on strange and charm quarks. Their interactions in the QGP are modeled using leading-order perturbative QCD...
Quarkonia and heavy-quark relaxation times in the quark-gluon plasma
Riek, F.; Rapp, Ralf.
2010-01-01T23:59:59.000Z
and heavy-quark diffusion on a common basis and thus to obtain mutual constraints. The two-body interaction kernel is approximated within a potential picture for spacelike momentum transfers. An effective field-theoretical model combining color-Coulomb...
Flavor Physics in the Quark Sector
Antonelli, Mario; /Frascati; Asner, David Mark; /Carleton U.; Bauer, Daniel Adams; /Imperial Coll., London; Becher, Thomas G.; /Fermilab; Beneke, M.; /Aachen, Tech. Hochsch.; Bevan, Adrian John; /Queen Mary, U. of London; Blanke, Monika; /Munich, Tech. U. /Munich, Max Planck Inst.; Bloise, C.; /Frascati; Bona, Marcella; /CERN; Bondar, Alexander E.; /Novosibirsk, IYF; Bozzi, Concezio; /INFN, Ferrara; Brod, Joachim; /Karlsruhe U.; Buras, Andrzej J.; /Munich, Tech. U.; Cabibbo, N.; /INFN, Rome /Rome U.; Carbone, A.; /INFN, Bologna; Cavoto, Gianluca; /INFN, Rome; Cirigliano, Vincenzo; /Los Alamos; Ciuchini, Marco; /INFN, Rome; Coleman, Jonathon P.; /SLAC; Cronin-Hennessy, Daniel P.; /Minnesota U.; Dalseno, J.P.; /KEK, Tsukuba /Glasgow U. /Queen Mary, U. of London /Freiburg U. /Charles U. /Pisa U. /Vienna, OAW /Imperial Coll., London /Bergen U. /INFN, Rome /Rome U. /Munich, Tech. U. /INFN, Rome /Rome U. /Southampton U. /INFN, Rome /Nara Women's U. /Florida U. /INFN, Turin /Turin U. /Edinburgh U. /Warwick U. /INFN, Rome /Rome U. /Massachusetts U., Amherst /KEK, Tsukuba /Bern U. /CERN /Munich, Tech. U. /Mainz U., Inst. Phys. /Wayne State U. /Munich, Max Planck Inst. /CERN /Frascati /Brookhaven /Mainz U., Inst. Kernphys. /Munich, Tech. U. /Siegen U. /Imperial Coll., London /Victoria U. /KEK, Tsukuba /Fermilab /Washington U., St. Louis /Frascati /Warwick U. /Indian Inst. Tech., Madras /Melbourne U. /Princeton U. /Beijing, Inst. High Energy Phys. /INFN, Rome /INFN, Rome3 /Fermilab /SLAC /York U., Canada /Brookhaven /UC, Irvine /INFN, Rome /Rome U. /Valencia U., IFIC /INFN, Padua /Padua U. /Munich, Max Planck Inst. /Barcelona U. /Warwick U. /Tata Inst. /Frascati /Mainz U., Inst. Phys. /Vienna U. /KEK, Tsukuba /Orsay, LPT /Frascati /Munich, Tech. U. /Brookhaven /Bern U. /CERN /Mainz U., Inst. Phys. /Wayne State U. /Valencia U., IFIC /CERN /Kentucky U. /Oxford U. /Iowa State U. /Bristol U. /INFN, Rome /Rutherford /CERN /Orsay, LAL /Glasgow U. /INFN, Padua /Queen Mary, U. of London /Texas U. /LPHE, Lausanne /Fermilab /UC, Santa Cruz /Vienna, OAW /Cincinnati U. /Frascati /Orsay, LAL /Ohio State U. /Purdue U. /Novosibirsk, IYF /Frascati /INFN, Rome /Padua U. /INFN, Rome /Bern U. /Karlsruhe U. /Brookhaven /CERN /Paris U., VI-VII /Zurich, ETH /Pisa U. /Frascati /Oxford U. /Orsay, LAL /INFN, Rome2 /INFN, Rome /INFN, Rome3 /Princeton U. /Fermilab /Queen's U., Kingston /KEK, Tsukuba /Melbourne U. /Brookhaven /Indiana U. /INFN, Rome /Rome U. /Pisa U. /Mainz U., Inst. Phys. /Karlsruhe U. /Oxford U. /Cambridge U., DAMTP /Edinburgh U. /CERN
2010-08-26T23:59:59.000Z
In the past decade, one of the major challenges of particle physics has been to gain an in-depth understanding of the role of quark flavor. In this time frame, measurements and the theoretical interpretation of their results have advanced tremendously. A much broader understanding of flavor particles has been achieved, apart from their masses and quantum numbers, there now exist detailed measurements of the characteristics of their interactions allowing stringent tests of Standard Model predictions. Among the most interesting phenomena of flavor physics is the violation of the CP symmetry that has been subtle and difficult to explore. In the past, observations of CP violation were confined to neutral K mesons, but since the early 1990s, a large number of CP-violating processes have been studied in detail in neutral B mesons. In parallel, measurements of the couplings of the heavy quarks and the dynamics for their decays in large samples of K,D, and B mesons have been greatly improved in accuracy and the results are being used as probes in the search for deviations from the Standard Model. In the near future, there will be a transition from the current to a new generation of experiments, thus a review of the status of quark flavor physics is timely. This report is the result of the work of the physicists attending the 5th CKM workshop, hosted by the University of Rome 'La Sapienza', September 9-13, 2008. It summarizes the results of the current generation of experiments that is about to be completed and it confronts these results with the theoretical understanding of the field which has greatly improved in the past decade.
Studies of top quark production at D0
Gerber, Cecilia E.; /Illinois U., Chicago
2011-07-01T23:59:59.000Z
I present recent results on top quark production in pp collisions at a center of mass energy of 1.96 TeV. The studies were performed by the D0 collaboration using approximately 5 fb{sup -1} of data taken during Run II at the Fermilab Tevatron accelerator. The top quark is the heaviest known elementary particle and completes the quark sector of the three-generation structure of the standard model (SM). It differs from the other quarks not only by its much larger mass, but also by its lifetime which is too short to build hadronic bound states. The SM predicts that top quarks are created via two independent production mechanisms at hadron colliders. The primary mode, in which a t{bar t} pair is produced from a gtt vertex via the strong interaction, was used by the D0 and CDF collaborations to establish the existence of the top quark in 1995. The second production mode of top quarks at hadron colliders is the electroweak production of a single top quark from a Wtb vertex. The predicted cross section for single top quark production is about half that of t{bar t} pairs but the signal-to-background ratio is much worse; observation of single top quark production has therefore until recently been impeded by its low rate and difficult background environment compared to the top pair production. In the following sections I will present results for the measurement of the t{bar t} pair and the single top quark production cross section using respectively 5.3 fb{sup -1} and 5.4 fb{sup -1} of data taken by the D0 experiment.
Top Quark Spin Correlations at the Tevatron
Head, Tim; /Manchester U.
2010-07-01T23:59:59.000Z
Recent measurements of the correlation between the spin of the top and the spin of the anti-top quark produced in proton anti-proton scattering at a center of mass energy of {radical}s = 1.96 Tev by the CDF and D0 collaborations are discussed. using up to 4.3 fb{sup -1} of data taken with the CDF and D0 detectors the spin correlation parameter C, the degree to which the spins are correlated, is measured in dileptonic and semileptonic final states. The measurements are found to be in agreement with Standard Model predictions.
Photon emission from bare quark stars
B. G. Zakharov
2010-08-16T23:59:59.000Z
We investigate the photon emission from the electrosphere of a quark star. It is shown that at temperatures T\\sim 0.1-1 MeV the dominating mechanism is the bremsstrahlung due to bending of electron trajectories in the mean Coulomb field of the electrosphere. The radiated energy for this mechanism is much larger than that for the Bethe-Heitler bremsstrahlung. The energy flux from the mean field bremsstrahlung exceeds the one from the tunnel e^{+}e^{-} pair creation as well. We demonstrate that the LPM suppression of the photon emission is negligible.
Top quark mass measurements at the LHC
Fuster, Juan; The ATLAS collaboration
2015-01-01T23:59:59.000Z
The latest measurements of the top quark mass using the ATLAS and CMS experiments at the LHC are presented. The discussion includes the results obtained using the conventional methods (Template/Ideogram) and those derived from the so called alternative methods. Results from the conventional methods using the various top final states (lepton+jets, di-lepton and full hadronic) are reviewed. Determinations using the inclusive ttbar production, the ttbar production with an additional jet and the lepton-b-jet invariant mass distribution are also discussed.
Jet conversions in a quark-gluon plasma
Liu, W.; Ko, Che Ming; Zhang, B. W.
2007-01-01T23:59:59.000Z
Quark and gluon jets traversing through a quark-gluon plasma not only lose their energies but also can undergo flavor conversions. The conversion rates via the elastic q((q) over bar )g -> gq((q) over bar )and the inelastic q (q) over bar gg...
Jet conversions in a quark-gluon plasma
Liu, W.; Ko, Che Ming; Zhang, B. W.
2007-01-01T23:59:59.000Z
Quark and gluon jets traversing through a quark-gluon plasma not only lose their energies but also can undergo flavor conversions. The conversion rates via the elastic q((q) over bar )g -> gq((q) over bar )and the inelastic q (q) over bar gg...
Electrical conductivity of quark matter in magnetic field
B. Kerbikov; M. Andreichikov
2011-12-05T23:59:59.000Z
Fermion currents in dense quark matter embedded into magnetic field are under intense discussions motivated by Chiral Magnetic Effect. We argue that conductivity of quark matter may be independent of the magnetic field direction and not proportional to the magnetic field strength.
Search for charged Higgs bosons in top quark decays
Baringer, Philip S.; Bean, Alice; Clutter, Justace Randall; Moulik, Tania; Wilson, Graham Wallace; DØ Collaboration; Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Aguilo, E.; Ahsan, M.
2009-12-07T23:59:59.000Z
We present a search for charged Higgs bosons in top quark decays. We analyze the e+jetse+jets, ?+jets?+jets, ee, e?, ??, ?e and ?? final states from top quark pair production events, using data from about 1 fb^(?1) of integrated luminosity recorded...
High temperature QCD with three flavors of improved staggered quarks
The MILC Collaboration; C. Bernard; T. Burch; C. E. DeTar; Steven Gottlieb; Eric Gregory; U. M. Heller; J. Osborn; R. L. Sugar; D. Toussaint
2002-09-05T23:59:59.000Z
We present an update of our study of high temperature QCD with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad staggered quark action. Simulations are being carried out on lattices with Nt=4, 6 and 8 for the case of three degenerate quarks with masses less than or equal to the strange quark mass, $m_s$, and on lattices with Nt=6 and 8 for degenerate up and down quarks with masses in the range 0.2 m_s \\leq m_{u,d} \\leq 0.6 m_s, and the strange quark fixed near its physical value. We also report on first computations of quark number susceptibilities with the Asqtad action. These susceptibilities are of interest because they can be related to event-by-event fluctuations in heavy ion collision experiments. Use of the improved quark action leads to a substantial reduction in lattice artifacts. This can be seen already for free fermions and carries over into our results for QCD.
High temperature QCD with three flavors of improved staggered quarks
Bernard, C; DeTar, C E; Gottlieb, S; Gregory, E; Heller, U M; Osborn, J; Sugar, R L; Toussaint, D; Gottlieb, Steven; Gregory, Eric
2002-01-01T23:59:59.000Z
We present an update of our study of high temperature QCD with three flavors of quarks, using a Symanzik improved gauge action and the Asqtad staggered quark action. Simulations are being carried out on lattices with Nt=4, 6 and 8 for the case of three degenerate quarks with masses less than or equal to the strange quark mass, $m_s$, and on lattices with Nt=6 and 8 for degenerate up and down quarks with masses in the range 0.2 m_s \\leq m_{u,d} \\leq 0.6 m_s, and the strange quark fixed near its physical value. We also report on first computations of quark number susceptibilities with the Asqtad action. These susceptibilities are of interest because they can be related to event-by-event fluctuations in heavy ion collision experiments. Use of the improved quark action leads to a substantial reduction in lattice artifacts. This can be seen already for free fermions and carries over into our results for QCD.
Preon Trinity - a new model of leptons and quarks
Jean-Jacques Dugne; Sverker Fredriksson; Johan Hansson; Enrico Predazzi
1999-10-12T23:59:59.000Z
A new model for the substructure of quarks, leptons and weak gauge bosons is discussed. It is based on three fundamental and absolutely stable spin-1/2 preons. Its preon flavour SU(3) symmetry leads to a prediction of nine quarks, nine leptons and nine heavy vector bosons. One of the quarks has charge $-4e/3$, and is speculated to be the top quark (whose charge has not been measured). The flavour symmetry leads to three conserved lepton numbers in all known weak processes, except for some neutrinos, which might either oscillate or decay. There is also a (Cabibbo) mixing of the $d$ and $s$ quarks due to an internal preon-antipreon annihilation channel. An identical channel exists inside the composite $Z^0$, leading to a relation between the Cabibbo and Weinberg mixing angles.
XQCAT: eXtra Quark Combined Analysis Tool
D. Barducci; A. Belyaev; M. Buchkremer; J. Marrouche; S. Moretti; L. Panizzi
2015-09-17T23:59:59.000Z
XQCAT (eXtra Quark Combined Analysis Tool) is a tool aimed at determining exclusion confidence levels for scenarios of new physics characterised by the presence of one or multiple heavy extra quarks which interact through Yukawa couplings with any of the Standard Model quarks. The code uses a database of efficiencies for pre-simulated processes of QCD-induced pair production of extra quarks and their subsequent on-shell decays. In the version 1.2 of XQCAT the efficiencies have been computed for a set of seven publicly available search results by the CMS experiment. The input for the code is a text file in which masses, branching ratios and dominant chirality of the couplings of the new quarks are provided. The output of the code is the exclusion confidence levels of the test point for each implemented experimental analysis considered individually and, when possible, in statistical combination.
Cooling of Neutron Stars with Color Superconducting Quark Cores
David Blaschke; Dmitri N. Voskresensky; Hovik Grigorian
2005-11-03T23:59:59.000Z
We show that within a recently developed nonlocal chiral quark model the critical density for a phase transition to color superconducting quark matter under neutron star conditions can be low enough for these phases to occur in compact star configurations with masses below 1.3 M_sun. We study the cooling of these objects in isolation for different values of the gravitational mass and argue that, if the quark matter phase would allow unpaired quarks, the corresponding hybrid stars would cool too fast. The comparison with observational data puts tight constraints on possible color superconducting quark matter phases. Possible candidates with diquark gaps of the order of 10 keV - 1 MeV such as the "2SC+X" and the color spin locking (CSL) phase are presented.
Ulm, Universität
-peter.grossmann@uni-ulm.de WWW: http://www.uni-ulm.de/omi Energiemanagement in isolierten Systemen Hybridisierung von Fahrzeugantrieben Prädiktives Energiemanagement im Fahrzeugbetrieb Universität Ulm, Institut für Energiewandlung und
Knobloch,Jürgen
. Mathematik und Physik Mathematik Physik PLm (30 min) PLm (30 min) 22 15 7 3. 2. Informatik PLs (180 min) 8 1. Praktikum Grundlagen der Automatisierungstechnik PLs (180 min), PLm (30) PLs (120 min) T (Prakt.) PLs (60
Manstein, Dietmar J.
.-Psych. Susanne Bauer Dr. Dipl.-Psych. Albina Zeef 18.02.2013 Hysterie als Modus der Konfliktverarbeitung und als am Beispiel der konzentrativen Bewegungstherapie Prof. Dr. Dipl.-Psych. Klaus-Peter Seidler 11
Kuhlen, Rainer
Neue Infrastruktur für Information, Kommunikation und Multimedia (IKM) Folie 1Information Engineering - Department of Computer and Information Science at the University of Constance Prof. Dr. Rainer Kuhlen Chair for Information Science In Richtung einer neuen Infrastruktur für Information, Kommunikation
Kuehnlenz, Kolja
Diploma Supplement: Aktivitätenliste und Laufzettel (Stand: September 2011) Laufzettel (Nr. ___ von keine extracurricularen Aktivitäten oder Auslandsaufenthalte in mein Diploma Supplement aufgenommen werden. Es sollen folgende Aktivitäten/Auslandsaufenthalte in mein Diploma Supplement aufgenom- men
Duan Chun-Gui; Liu Na
2008-09-28T23:59:59.000Z
By means of two typical kinds of quark energy loss parametrization and the nuclear parton distributions determined only with lepton-nuclear deep inelastic scattering experimental data, a leading order analysis are performed on the proton-induced Drell-Yan differential cross section ratios of tungsten versus deuterium as a function of the quark momentum fraction in the beam proton and target nuclei. It is found that the theoretical results with quark energy loss are in good agreement with the experimental data. The quark energy loss effect produce approximately 3% to 11% suppression on the Drell-Yan differential cross section ratios $R_{W/D}$ in the range $0.05\\leq x_2\\leq0.3$. The application of nuclear Drell-Yan data with heavy targets is remarkably subject to difficulty in the constraints of the nuclear sea-quark distribution.
Top Quark Properties in Little Higgs Models
Berger, C.F.; /SLAC; Perelstein, M.; /Cornell U., CIHEP; Petriello, F.; /Wisconsin U., Madison
2005-12-08T23:59:59.000Z
Identifying the mechanism which breaks electroweak symmetry and generates fermion masses is one of the main physics goals for both the LHC and the ILC. Studies of the top quark have the potential to illuminate this issue; since it is the heaviest of the Standard Model (SM) fermions, the top is expected to couple strongly to the symmetry-breaking sector. Consequently, the structure of that sector can have significant, potentially observable effects on the properties of the top. for example, it is well known that the vector and axial t{bar t}Z form factors receive large corrections (of order 5-10%) in certain models of dynamical electroweak symmetry breaking [1]. At future colliders such as the LHC and the ILC, we will be able to pursue a program of precision top physics, similar to the program studying the Z at LEP and SLC. In this manuscript, they study the corrections to the top quark properties in ''Little Higgs'' models of electroweak symmetry breaking [2], and compare the expected deviations from the SM predictions with expected sensitivities of experiments at the LHC and the ILC. In the Little Higgs models, electroweak symmetry is driven by the radiative effects from the top sector, including the SM-like top and its heavy counterpart, a TeV-scale ''heavy top'' T. Probing this structure experimentally is quite difficult. While the LHC should be able to discover the T quark, its potential for studying its couplings is limited [3,4]. Direct production of the T will likely be beyond the kinematic reach of the ILC. However, we will show below that the corrections to the gauge couplings of the SM top, induced by its mixing with the T, will be observable at the ILC throughout the parameter range consistent with naturalness. Measuring these corrections will provide a unique window on the top sector of the Little Higgs. Many Little Higgs models have been proposed in the literature. We will consider two examples in this study, the ''Littlest Higgs'' model [5], and its variation incorporating T parity [6].
Search for W-prime Boson Resonances Decaying to a Top Quark and a Bottom Quark
Abazov, V.M.; Abbott, B.; /Dubna, JINR; Abolins, M.; /Oklahoma U.; Acharya, B.S.; /Michigan State U.; Adams, M.; /Tata Inst.; Adams, T.; /Illinois U., Chicago; Aguilo, E.; /Florida State U.; Ahn, S.H.; /York U., Canada; Ahsan, M.; /Korea U., KODEL; Alexeev, G.D.; /Kansas State U.; Alkhazov, Georgiy; /Dubna, JINR /St. Petersburg, INP /Northeastern U.
2008-03-01T23:59:59.000Z
We search for the production of a heavy W{prime} gauge boson that decays to third generation quarks in 0.9 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, collected with the D0 detector at the Fermilab Tevatron collider. We find no significant excess in the final-state invariant mass distribution and set upper limits on the production cross section times branching fraction. For a left-handed W{prime} boson with SM couplings, we set a lower mass limit of 731 GeV. For right-handed W{prime} bosons, we set lower mass limits of 739 GeV if the W{prime} boson decays to both leptons and quarks and 768 GeV if the W{prime} boson decays only to quarks. We also set limits on the coupling of the W{prime} boson to fermions as a function of its mass.
Top Quark Production Measurements at ATLAS
Robert Calkins; for the ATLAS Collaboration
2011-10-05T23:59:59.000Z
An overview of top quark production measurements using the ATLAS detector at the LHC is presented. Using 35 pb^-1 of data, we measured the ttbar cross-section in the lepton+jets channel to 13% precision and set limits on the cross-section for the all hadronic decay channel. The measurement in the dilepton channel was performed using 0.70 fb^-1 of data and was combined with the lepton+jets channel result for our most precise ttbar cross-section measurement of \\sigma(ttbar+X) =176 +- 5(stat) +13 -10 (syst) +-7(lumi). Single top production was also measured in the t-channel using 0.70 fb^-1 of data.
Constituent gluons and the static quark potential
Greensite, Jeff
2015-01-01T23:59:59.000Z
We suggest that Hamiltonian matrix elements between physical states in QCD might be approximated, in Coulomb gauge, by "lattice-improved" tree diagrams; i.e. tree diagram contributions with dressed ghost, transverse gluon, and Coulomb propagators obtained from lattice simulations. Such matrix elements can be applied to a variational treatment of hadronic states which include constituent gluons. As an illustration and first application of this hybrid approach, we derive a variational estimate of the heavy quark potential for distances up to 2.5 fm. The Coulomb string tension in SU(3) gauge theory is about a factor of four times greater than the asymptotic string tension. In our variational approach, using for simplicity a single variational parameter, we can reduce this overshoot by nearly the factor required. The building blocks of our approach are Coulomb gauge propagators, and in this connection we present new lattice results for the ghost and transverse gluon propagators in position space.
Constituent gluons and the static quark potential
Jeff Greensite; Adam P. Szczepaniak
2015-05-19T23:59:59.000Z
We suggest that Hamiltonian matrix elements between physical states in QCD might be approximated, in Coulomb gauge, by "lattice-improved" tree diagrams; i.e. tree diagram contributions with dressed ghost, transverse gluon, and Coulomb propagators obtained from lattice simulations. Such matrix elements can be applied to a variational treatment of hadronic states which include constituent gluons. As an illustration and first application of this hybrid approach, we derive a variational estimate of the heavy quark potential for distances up to 2.5 fm. The Coulomb string tension in SU(3) gauge theory is about a factor of four times greater than the asymptotic string tension. In our variational approach, using for simplicity a single variational parameter, we can reduce this overshoot by nearly the factor required. The building blocks of our approach are Coulomb gauge propagators, and in this connection we present new lattice results for the ghost and transverse gluon propagators in position space.
Heavy Quark Production at the Tevatron
Sally Seidel
2008-08-25T23:59:59.000Z
Results are presented from four CDF analyses involving heavy quark production in proton-antiproton collisions at center of mass energy 1.96 TeV. The shapes of b-jets are found to be broader than inclusive predictions and broader than both PYTHIA and HERWIG defaults. A measurement of the production cross section for psi(2S) is consistent with Run 1 results and with theoretical predictions associated with parton distribution function energy dependence. The inclusive b-jet production cross section is also consistent with theoretical predictions over six orders of magnitude. The b-bbar differential production cross section is compared to several theoretical models and found to be best described by MC@NLO + JIMMY.
Combined search for the quarks of a sequential fourth generation
CMS Collaboration
2013-03-13T23:59:59.000Z
Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.
Basic features of the pion valence-quark distribution function
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Chang, Lei; Mezrag, Cédric; Moutarde, Hervé; Roberts, Craig D.; Rodríguez-Quintero, Jose; Tandy, Peter C.
2014-10-07T23:59:59.000Z
The impulse-approximation expression used hitherto to define the pion's valence-quark distribution function is flawed because it omits contributions from the gluons which bind quarks into the pion. A corrected leading-order expression produces the model-independent result that quarks dressed via the rainbow–ladder truncation, or any practical analogue, carry all the pion's light-front momentum at a characteristic hadronic scale. Corrections to the leading contribution may be divided into two classes, responsible for shifting dressed-quark momentum into glue and sea-quarks. Working with available empirical information, we use an algebraic model to express the principal impact of both classes of corrections. This enables amore »realistic comparison with experiment that allows us to highlight the basic features of the pion's measurable valence-quark distribution, q?(x); namely, at a characteristic hadronic scale, q?(x)~(1-x)2 for x?0.85; and the valence-quarks carry approximately two-thirds of the pion's light-front momentum.« less
Marinova, Elena
Landnutzung in der Region von Ovcarovo-Gorata: Archäobotanische Forschungen zum Frühneolithikum einen diachronen Überblick der Landwirtschaft und Landnutzung in der Region von Ovcarovo-Gorata erlauben
Quarks and the Strong Force Summary/Review Spring 2009 Compton Lecture Series
groups: one with non-zero quark number and the other with zero quark number The non-zero quark number particles are all either spin 1/2 or spin 3/2. The zero quark number particles are all either spin 0 or spin exchange is a residual effect from the color structure of baryons which have no net color Protons
Dynamics of quark-gluon plasma from Field correlators
A. Di Giacomo; E. Meggiolaro; Yu. A. Simonov; A. I. Veselov
2005-12-22T23:59:59.000Z
It is argued that strong dynamics in the quark-gluon plasma and bound states of quarks and gluons is mostly due to nonperturbative effects described by field correlators. The emphasis in the paper is made on two explicit calculations of these effects from the first principles: one analytic using gluelump Green's functions and another using independent lattice data on correlators. The resulting hadron spectra are investigated in the range T_c MEM data. The possible role of these bound states in the thermodynamics of quark-gluon plasma is discussed.
Calculation of the strange quark mass using domain wall fermions
Tom Blum; Amarjit Soni; Matthew Wingate
2000-09-18T23:59:59.000Z
We present a first calculation of the strange quark mass using domain wall fermions. This paper contains an overview of the domain wall discretization and a pedagogical presentation of the perturbative calculation necessary for computing the mass renormalization. We combine the latter with numerical simulations to estimate the strange quark mass. Our final result in the quenched approximation is 95(26) MeV in the ${\\bar{MS}}$ scheme at a scale of 2 GeV. We find that domain wall fermions have a small perturbative mass renormalization, similar to Wilson quarks, and exhibit good scaling behavior.
Golden Bars of Consensus and the Truth Quark
Frank D. Tony Smith; jr
2002-05-14T23:59:59.000Z
Scientists are imprisoned by Golden Bars of Consensus, says Burton Richter (hep-ex/0001012). A case in point is the mass of the Truth Quark. The consensus analysis of the experimental data indicates that the mass of the Truth Quark is about 170 GeV. On the other hand, an alternative analysis of the same data indicates that the mass of the Truth Quark is about 130 GeV. If the design of future experiments, including trigger, event selection, data analysis procedures, error analysis, etc., takes into account only the consensus value, and if the consensus value happens to be incorrect, then results of future experiments might be compromised.
Combining Quark and Link Smearing to Improve Extended Baryon Operators
Adam Lichtl; Subhasish Basak; Robert Edwards; George T. Fleming; Urs M. Heller; Colin Morningstar; David Richards; Ikuro Sato; Stephen Wallace
2005-09-29T23:59:59.000Z
The effects of Gaussian quark-field smearing and analytic stout-link smearing on the correlations of gauge-invariant extended baryon operators are studied. Gaussian quark-field smearing substantially reduces contributions from the short wavelength modes of the theory, while stout-link smearing significantly reduces the noise from the stochastic evaluations. The use of gauge-link smearing is shown to be crucial for baryon operators constructed of covariantly-displaced quark fields. Preferred smearing parameters are determined for a lattice spacing a_s ~ 0.1 fm.
Measurements of Top Quark Properties at the Tevatron
Mietlicki, David J.; /Michigan U.
2012-04-01T23:59:59.000Z
The top quark is the most recently discovered of the standard model quarks, and studies of its properties are important tests of the standard model. Many measurements of top properties have been produced by the CDF and D0 collaborations, which study top quarks produced in p{bar p} collisions at the Fermilab Tevatron with a center-of-mass energy {radical}s = 1.96 TeV. We describe recent results from top properties measurements at the Tevatron using datasets corresponding to integrated luminosities up to 8.7 fb{sup -1}.
On the Energy Loss of High Energy Quarks in a Finite-Size Quark-Gluon Plasma
B. G. Zakharov
2000-12-28T23:59:59.000Z
We study within the light-cone path integral approach the induced gluon emission from a fast quark passing through a finite-size QCD plasma. We show that the leading log approximation used in previous studies fails when the gluon formation length becomes of the order of the length of the medium traversed by the quark. Calculation of the energy loss beyond the leading log approximation gives the energy loss which grows logarithmically with quark energy contrary to the energy independent prediction of the leading log approximation.
Dynamical quark loop light-by-light contribution to muon g-2 within the nonlocal chiral quark model
A. E. Dorokhov; A. E. Radzhabov; A. S. Zhevlakov
2015-07-24T23:59:59.000Z
The hadronic corrections to the muon anomalous magnetic moment a_mu, due to the gauge-invariant set of diagrams with dynamical quark loop light-by-light scattering insertions, are calculated in the framework of the nonlocal chiral quark model. These results complete calculations of all hadronic light-by-light scattering contributions to a_mu in the leading order in the 1/Nc expansion. The result for the quark loop contribution is a_mu^{HLbL,Loop}=(11.0+-0.9)*10^(-10), and the total result is a_mu^{HLbL,NxQM}=(16.8+-1.2)*10^(-10).
/289 24672 diana.belik@tum.de Ernährung, Landnutzung und Umwelt Frau Christa Gillmann Frau Christine Hirsch
Kaon semileptonic decay form factors with HISQ valence quarks
E. Gamiz; J. A. Bailey; A. Bazavov; C. Bernard; C. Bouchard; C. DeTar; D. Du; A. X. El-Khadra; J. Foley; E. D. Freeland; Steven Gottlieb; U. M. Heller; J. Kim; A. S. Kronfeld; J. Laiho; L. Levkova; P. B. Mackenzie; E. T. Neil; M. B. Oktay; Si-Wei Qiu; J. N. Simone; R. Sugar; D. Toussaint; R. S. Van de Water; R. Zhou
2012-11-05T23:59:59.000Z
We report on the status of our kaon semileptonic form factor calculations using the highly-improved staggered quark (HISQ) formulation to simulate the valence fermions. We present results for the form factor f_+^{K \\pi}(0) on the asqtad N_f=2+1 MILC configurations, discuss the chiral-continuum extrapolation, and give a preliminary estimate of the total error. We also present a more preliminary set of results for the same form factor but with the sea quarks also simulated with the HISQ action; these results include data at the physical light quark masses. The improvements that we expect to achieve with the use of the HISQ configurations and simulations at the physical quark masses are briefly discussed.
QCD thermodynamics with Wilson quarks at large kappa
Tom Blum; Thomas A. DeGrand; Carleton DeTar; Steven Gottlieb; A. Hasenfratz; Leo Karkkainen; D. Toussaint; R. L. Sugar
1994-04-12T23:59:59.000Z
We have extended our study of the high temperature transition with two flavors of Wilson quarks on 12^3 x 6 lattices to kappa=0.19. We have also performed spectrum calculations on 12^3 x 24 lattices at kappa=0.19 to find the physical lattice spacing and quark mass. At this value of kappa the transition is remarkable in that the plaquette and psi-bar-psi show a large discontinuity while the Polyakov loop changes very little. This and several other features of the transition are more suggestive of a bulk transition than a transition to a quark-gluon plasma. However, if the temperature is estimated using the rho mass as a standard, the result is about 150 MeV, in agreement with the value found for the thermal transition with Kogut-Susskind quarks. uuencoded compressed Postscript file
Now Playing change Listen Live Search Quirks & Quarks
Whitney, David
of recent interviews with science authors. podcasts facebook twitter rss Stay Connected with Quirks & Quarks of an actual dinosaur, he used an actual elephant to do his experiment. What he found was that it made little
Measurement of Heavy Quark cross-sections at CDF
A. Annovi
2007-09-28T23:59:59.000Z
The measurement of heavy quark cross-sections provides important tests of the QCD theory. This paper reviews recent measurements of single b-quark and correlated b-quark cross-sections at CDF. Two new measurements of the single b-quark production at CDF agree with the first result from CDF Run II. This clarifies the experimental situation and confirms the recent agreement of theoretical prediction with data. A new measurement of the correlated $b\\bar{b}$ cross-section with dimuon events at CDF is presented. It agrees with theory and it does not confirm the anomalously large $b\\bar{b}$ cross-section seen in Run I by CDF and D${\
Modelling Hybrid Stars in Quark-Hadron Approaches
Schramm, S; Negreiros, R
2015-01-01T23:59:59.000Z
The density in the core of neutron stars can reach values of about 5 to 10 times nuclear matter saturation density. It is, therefore, a natural assumption that hadrons may have dissolved into quarks under such conditions, forming a hybrid star. This star will have an outer region of hadronic matter and a core of quark matter or even a mixed state of hadrons and quarks. In order to investigate such phases, we discuss different model approaches that can be used in the study of compact stars as well as being applicable to a wider range of temperatures and densities. One major model ingredient, the role of quark interactions in the stability of massive hybrid stars is discussed. In this context, possible conflicts with lattice QCD simulations are investigated.
Exploration of nucleon structure in lattice QCD with chiral quarks
Syritsyn, Sergey Nikolaevich
2010-01-01T23:59:59.000Z
In this work, we calculate various nucleon structure observables using the fundamental theory of quarks and gluons, QCD, simulated on a lattice. In our simulations, we use the full QCD action including Nf = 2+ 1 dynamical ...
Precision Top-Quark Mass Measurement at CDF
Gomez-Ceballos, Guillelmo
We present a precision measurement of the top-quark mass using the full sample of Tevatron ?s=1.96??TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of ...
Quark mass functions and pion structure in Minkowski space
Biernat, Elmer P. [CFTP, Institute Superior Tecnico; Gross, Franz L. [JLAB; Pena, Maria Teresa [CFTP, Institute Superior Tecnico; Stadler, Alfred [University of Evora
2014-03-01T23:59:59.000Z
We present a study of the dressed quark mass function and the pion structure in Minkowski space using the Covariant Spectator Theory (CST). The quark propagators are dressed with the same kernel that describes the interaction between different quarks. We use an interaction kernel in momentum space that is a relativistic generalization of the linear confining q-qbar potential and a constant potential shift that defines the energy scale. The confining interaction has a Lorentz scalar part that is not chirally invariant by itself but decouples from the equations in the chiral limit and therefore allows the Nambu--Jona-Lasinio (NJL) mechanism to work. We adjust the parameters of our quark mass function calculated in Minkowski-space to agree with LQCD data obtained in Euclidean space. Results of a calculation of the pion electromagnetic form factor in the relativistic impulse approximation using the same mass function are presented and compared with experimental data.
Iso-singlet Down Quark Mixing And CP Violation Experiments
Donovan Hawkins; Dennis Silverman
2002-05-01T23:59:59.000Z
We confront the new physics models with extra iso-singlet down quarks in the new CP violation experimental era with $\\sin{(2\\beta)}$ and $\\epsilon'/\\epsilon$ measurements, $K^+ \\to \\pi^+ \
First observation of top quark production in the forward region
Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; d'Argent, Philippe; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Birnkraut, Alex; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Brett, David; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Demmer, Moritz; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Di Ruscio, Francesco; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fohl, Klaus; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gastaldi, Ugo; Gauld, Rhorry; Gavardi, Laura; Gazzoni, Giulio; Geraci, Angelo; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Gianì, Sebastiana; Gibson, Valerie; Girard, Olivier Göran; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto
2015-01-01T23:59:59.000Z
Top quark production in the forward region in proton-proton collisions is observed for the first time. The $W\\!+\\!b$ final state with $W\\to\\mu\
Summary of the session on the top quark
Butler, Joel N.; /Fermilab
2011-01-01T23:59:59.000Z
The CDF and D0 experiments at the Fermilab Tevatron showed recent results on the production and properties of the top quark. The CMS and ATLAS experiments presented first observations of top events at the LHC. Prospects for the top physics at the LHC over the next few years were discussed. CDF and D0 have made remarkable progress in detemerining the properties of the top quark, which so far, conforms to the expectations of the SM. The sophisticated methods they have developed form the basis of the exploration that is now starting at the LHC. New methods, such as the use of boosted top quark signatures, will be necessary to realize fully the potential of the LHC for finding new high mass particles decaying to top and for searching for deviations from the SM. Prospects for the future of top quark physics are very bright.
Color superconductivity with determinant interaction in strange quark matter
Amruta Mishra; Hiranmaya Mishra
2006-08-28T23:59:59.000Z
We investigate the effect of six fermion determinant interaction on color superconductivity as well as on chiral symmetry breaking. Coupled mass gap equations and the superconducting gap equation are derived through the minimisation of the thermodynamic potential. The effect of nonzero quark -- antiquark condensates on the superconducting gap is derived. This becomes particularly relevant for the case of 2-flavor superconducting matter with unpaired strange quarks in the diquark channel. While the effect of six fermion interaction leads to an enhancement of u-d superconductivity, due to nonvanishing strange quark--antiquark condensates, such an enhancement will be absent at higher densities for u-s or d-s superconductivity due to early (almost) vanishing of light quark-- antiquark condensates.
Observation of $t$-channel electroweak top quark production
Triplett, Nathan; /Iowa State U.
2011-04-01T23:59:59.000Z
The top quark is the heaviest known fundamental particle, with a mass of 172.0{sub -1.3}{sup +0.9}GeV. This is nearly twice the mass of the second heaviest known particle, the Z boson, and roughly the mass of a gold atom. Because of its unusually large mass, studying the top quark may provide insight into the Higgs mechanism and other beyond the standard model physics. Only two accelerators in the world are powerful enough to produce top quarks. The Tevatron, which first accelerated protons in 1983, has produced almost 400,000 top quarks, roughly half at each of its two detectors: DO and CDF. The LHC is a much newer accelerator which currently has accumulated about 0.5% as much data as the Tevatron. However, when running at full luminosity, the LHC is capable of producing a top quark about once every second and will quickly surpass the Tevatron as the leading producer of top quarks. This analysis uses data from the D0 detector at the Tevatron, which are described in chapter 3. Top quarks are produced most often in pairs of top and anti-top quarks through an interaction of the strong force. This production mode was first observed in 1995 at the Tevatron. However, top quarks can also be produced though an electroweak interaction, which produces just one top quark. This production mode was first observed at the Tevatron in 2008. Single top quark production can occur in different channels. In this analysis, a measurement of the cross section of the t-channel production mode is performed. This measurement uses 5.4 fb{sup -1} of data and uses the technique of boosted decision trees in order to separate signal from background events. The t-channel cross section is measured to be: {sigma}(p{bar p} {yields} tqb + X) = 3.03{sub -0.66}{sup +0.78}pb (0.0.1). Additional cross section measurements were also performed for the s-channel as well as the s + t-channel. The measurement of each one of these three cross sections was repeated three times using different techniques, and all three methods were combined into a 'super-method' which achieves the best performance. The details of these additional measurements are shown in appendix A.
Apyan, Aram
A search for a standard model Higgs boson produced in association with a top-quark pair and decaying to bottom quarks is presented. Events with hadronic jets and one or two oppositely charged leptons are selected from a ...
Searching for the fourth family quarks through anomalous decays
Sahin, M.; Sultansoy, S.; Turkoz, S. [TOBB University of Economics and Technology, Physics Division, Ankara (Turkey); TOBB University of Economics and Technology, Physics Division, Ankara, Turkey and Institute of Physics, National Academy of Sciences, Baku (Azerbaijan); Ankara University, Department of Physics, Ankara (Turkey)
2010-09-01T23:59:59.000Z
The flavor democracy hypothesis predicts the existence of the fourth standard model family. Because of the high masses of the fourth family quarks, their anomalous decays could be dominant if certain criteria are met. This will drastically change the search strategy at hadron colliders. We show that the fourth standard model family down quarks with masses up to 400-450 GeV can be observed (or excluded) via anomalous decays by Tevatron.
Gluon Radiation off Massive Quarks in a QCD Medium
N. Armesto; C. A. Salgado; U. A. Wiedemann
2004-05-19T23:59:59.000Z
Medium-induced gluon radiation from massless and massive quarks is treated in the same formalism. The dead cone which regulates gluon radiation from massive quarks in the vacuum at small angles, is filled in the medium but constitutes a small fraction of the available phase space. Our study indicates that the energy loss for charmed hadrons at RHIC should be smaller than for light hadrons, but still sizable.
Shear viscosity and spectral function of the quark matter
Masaharu Iwasaki; Hiromasa Ohnishi; Takahiko Fukutome
2006-06-19T23:59:59.000Z
We discuss the shear viscosity of the quark matter by using the Kubo-Mori formula. It is found that the shear viscosity is expressed in terms of the quark spectral function. If the spectral function is approximated by a modified Bright-Wigner type, the viscosity decreases as the width of the spectral function increases. We also discuss dependence of the shear viscosity on the temperature and the density.
Transverse quark distribution in mesons: QCD sum rule approach
Lee, S.H.; Hatsuda, T.; Miller, G.A. (Department of Physics, FM-15, University of Washingtion, Seattle, Washington 98195 (United States) Department of Physics, Yonsei University, Seoul 120-749 (Korea, Republic of))
1994-04-11T23:59:59.000Z
QCD sum rules are used to compute the first few moments of the mesonic quark momentum. Transverse, longitudinal, and mixed transverse-longitudinal components are examined. The transverse size of the pion is shown to be dictated by the gluon condensate, even though the mass and the longitudinal distribution are dominated by the quark condensate. The implications of our results for color transparency physics and finite temperature QCD are discussed.
Reconstructing top quark-antiquark events with one lost jet
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Demina, Regina [Univ. of Rochester, Rochester, NY (United States); Harel, Amnon [Univ. of Rochester, Rochester, NY (United States); Orbaker, Douglas [Univ. of Rochester, Rochester, NY (United States)
2015-07-01T23:59:59.000Z
We present a technique for reconstructing the kinematics of pair-produced top quarks that decay to a charged lepton, a neutrino and four final state quarks in the subset of events where only three jets are reconstructed. We present a figure of merit that allows for a fair comparison of reconstruction algorithms without requiring their calibration. The new reconstruction of events with only three jets is fully competitive with the full reconstruction typically used for four-jet events.
Reconstructing top quark-antiquark events with one lost jet
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Demina, Regina; Harel, Amnon; Orbaker, Douglas
2015-04-02T23:59:59.000Z
We present a technique for reconstructing the kinematics of pair-produced top quarks that decay to a charged lepton, a neutrino and four final state quarks in the subset of events where only three jets are reconstructed. We present a figure of merit that allows for a fair comparison of reconstruction algorithms without requiring their calibration. The new reconstruction of events with only three jets is fully competitive with the full reconstruction typically used for four-jet events.
Breu, Ruth
. Stück 291. Reform des Studienplans der Studienrichtung Geschichte an der Karl-Franzens- Universität Graz Anhörungsverfahren gem. § 12 Abs. 2 UniStG 292. Reform der Studienpläne für die Lehramtsfächer Deutsch, Englisch. Reform des Studienplans der Studienrichtung Wirtschaftsingenieurwesen -Technische Chemie und Technische
Middeldorp, Aart
gemäß § 14 UniStG 79. Reform des Studienplans für das Diplomstudium Physik an der Karl-Franzens- Universität Graz 80. Reform des Studienplans für die Studienrichtung Volkskunde an der Karl-Franzens- Universität Graz 81. Reform des Studienplanes Sozialwirtschaft als sozial- und wirtschaftswissenschaftliche
Breu, Ruth
2000/2001 Ausgegeben am 16. Mai 2001 21. Stück 438. Reform des Studienplans für die Studienrichtung Begutachtungsverfahren gemäß § 14 UniStG 439. Reform des Studienplanes für das Doktoratsstudium der Sozial- und Wirtschaftswissenschaften an der Karl-Franzens-Universität Graz - Begutachtungsverfahren 440. Reform des Studienplanes für
Jet conversions in a quark-gluon plasma
W. Liu; C. M. Ko; B. W. Zhang
2007-05-05T23:59:59.000Z
Quark and gluon jets traversing through a quark-gluon plasma not only lose their energies but also can undergo flavor conversions. The conversion rates via the elastic $q(\\bar q)g\\to gq(\\bar q)$ and the inelastic $q\\bar q\\leftrightarrow gg$ scatterings are evaluated in the lowest order in QCD. Including both jet energy loss and conversions in the expanding quark-gluon plasma produced in relativistic heavy ion collisions, we have found a net conversion of quark to gluon jets. This reduces the difference between the nuclear modification factors for quark and gluon jets in central heavy ion collisions and thus enhances the $p/\\pi^+$ and ${\\bar p}/\\pi^-$ ratios at high transverse momentum. However, a much larger net quark to gluon jet conversion rate than the one given by the lowest-order QCD is needed to account for the observed similar ratios in central Au+Au and p+p collisions at same energy. Implications of our results are discussed.
On the effects of heavy sea quarks at low energies
Mattia Bruno; Jacob Finkenrath; Francesco Knechtli; Bjoern Leder; Rainer Sommer
2014-10-30T23:59:59.000Z
We present a factorisation formula for the dependence of light hadron masses and low energy hadronic scales on the mass $M$ of a heavy quark: apart from an overall factor $Q$, ratios such as $r_0(M)/r_0(0)$ are computable in perturbation theory at large $M$. The mass-independent factor $Q$ is obtained from the theory in the limit $M\\to0$ and the decoupled theory with the heavy quark removed. The perturbation theory part is stable concerning different loop orders and our non-perturbative results match on quantitatively to the perturbative prediction. Upon taking ratios of different hadronic scales at the same mass, the perturbative function drops out and the ratios are given by the decoupled theory up to $M^{-2}$ corrections. Our present numerical results are obtained in a model calculation where there are no light quarks and a heavy doublet of quarks is decoupled. They are limited to masses a factor two below the charm. This is not large enough to see the $M^{-2}$ scaling predicted by the theory, but it is sufficient to verify - in the continuum limit - that the sea quark effects of quarks with masses around the charm mass are very small.
Observation of the top quark with the DO detector
Hadley, N.J. [Univ. of Maryland, College Park, MD (United States)
1997-01-01T23:59:59.000Z
The DO Collaboration reports on the observation of the top quark in p{bar p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. We measure the top quark mass to be 199{sub -21}{sup -19}(stat){sub -21}{sup +14}(syst.) GeV/c{sup 2} and its production cross section to be 6.4 {+-}2.2 pb. Our result is based on approximately 50 pb{sup -1} of data. We observe 17 events with an expected background of 3.8 {+-} 0.6 events. The probability of an upward fluctuation of the background to produce the observed signal is 2 x 10{sup -6} (equivalent to 4.6 standard deviations). The kinematic properties of the events are consistent with top quark decay, and the distribution of events across the seven decay channels is consistent with the Standard Model top quark branching fractions. We describe the analysis that led to the observation of the top quark as well as the properties of the top quark events.
Sea Quark Flavor Asymmetry of Hadrons in Statistical Balance Model
Bin Zhang; Yong-Jun Zhang
2010-10-20T23:59:59.000Z
We derive a Menta Carlo method to simulate kinetic equilibrium ensemble, and get the same sea-quark flavor asymmetry as the linear equations method in statistical model. In the recent paper, we introduce the spilt factors to indicate the quarks' or gluons' spilt $g\\rightarrow q\\bar{q}(gg)$ and $q\\rightarrow qg$ ability. We obtain the almost fixed asymmetry value $0.12-0.16$ which consists with experimental measurements for proton, when the spilt factors vary in a very wide range over four orders of magnitude. So, we proof the sea quark asymmetry can be derived from statistic principle and not sensitively dependents on the dynamics details of quarks and gluons in proton. We also apply the Menta Carlo method of statistical model to predict the sea-quark asymmetry values for $K$ mesons, octet baryons $\\Sigma$,$\\Xi$ and $\\Delta$ baryons, even for exotic pentaquark states. All these asymmetry values just only dependent on the valence quarks numbers in those hadrons.
Big Bang Day: 5 Particles - 2. The Quark
None
2011-04-25T23:59:59.000Z
Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 2. The Quark "Three Quarks for Master Mark! Sure he hasn't got much of a bark." James Joyce's Finnegans Wake left its mark on modern physics when physicist Murray Gell Mann proposed this name for a group of hypothetical subatomic particles that were revealed in 1960 as the fundamental units of matter. Basic particles it seems are made up of even more basic units called quarks that make up 99.9% of visible material in the universe.. But why do we know so little about them? Quarks have never been seen as free particles but instead, inextricably bound together by the Strong Force that in turn holds the atomic nucleus together. This is the hardest of Nature's fundamental forces to crack, but recent theoretical advances, mean that the properties of the quark are at last being revealed.
Study on Screenning Length of Quark-AntiQuark Pair in a Hot Plasma of Two Dimensional Sphere
Atmaja, Ardian Nata
2011-01-01T23:59:59.000Z
We study screening length of a quark-antiquark pair moving in a plasma, corresponds to four dimensional AdS-Schwarzschild Black Hole, in AdS/CFT correspondence. The geodesic solution of the ends of string at the boundary reduces the problem to the motion in equatorial plane in which the separation length $L$ of quark-antiquark pair is parallel to the angular velocity $\\omega$. The string configuration for quark-antiquark pair is parameterized by momentum transfer $P$ which is related to momentum transfer in the drag force configuration. We compare the result by computing the screening length in quark-antiquark reference frame where the gravity dual is four dimensional Kerr-AdS Black Hole and we find a relation between mass parameters $M_{Sch}$ of Schwarzschild-AdS Black Hole and $M_{Kerr}$ of Kerr-AdS Black Hole in large mass limit.
Quark antiquark energies and the screening mass in a Quark-Gluon plasma at low and high temperatures
O. Kaczmarek; F. Zantow
2005-12-22T23:59:59.000Z
We discuss quark antiquark energies and the screening mass in hot QCD using the non-perturbative lattice approach. For this purpose we analyze properties of quark antiquark energies and entropies at infinitely large separation of the quark antiquark pair at low and high temperatures. In the limit of high temperatures these energies and entropies can be related perturbatively to the temperature dependence of the Debye mass and the coupling. On the one hand our analysis thus suggests that the quark antiquark energies at (infinite) large distances are rather related to the Debye screening mass and the coupling than to the temperature dependence of heavy-light meson masses. On the other hand we find no or only little differences in all mass scales introduced by us when changing from quenched to 2-flavor QCD at temperatures which are only moderately above the phase transition.
Taylor, Frank E.
Using a sample of dilepton top-quark pair (t[bar over t]) candidate events, a study is performed of the production of top-quark pairs together with heavy-flavor (HF) quarks, the sum of t[bar over t] + b + X and t[bar over ...
Gomez-Ceballos, Guillelmo
We present a search for a new heavy particle X produced in association with a top quark, pp? ?t(X?t? q) or pp? ?t? (X? ?tq? ), where q stands for up quarks and down quarks. Such a particle may explain the recent anomalous ...
Top quark physics at the Tevatron
Bhat, P.C.
1998-04-01T23:59:59.000Z
The authors review the analyses of t{bar t} candidate events in various decay channels, carried out using the p{bar p} collider data at {radical}s = 1.8 TeV by the CDF and D0 collaborations at the Fermilab Tevatron. The measurements of the top quark mass (m{sub t}) using lepton+jets channel yield m{sub t} = 173.3 {+-} 7.8 GeV/c{sup 2} from D0 analysis and m{sub t} = 175.9 {+-} 6.9 GeV/c{sup 2} from CDF analysis. The production cross section is measured to be {sigma}{sub t{bar t}} = 7.6{sub -1.5}{sup +1.8} pb by CDF and {sigma}{sub t{bar t}} = 5.6 {+-} 1.8 pb by D0. Further investigations using t{bar t} decays and future prospects are briefly discussed.
Strange Quark Contribution to the Nucleon - (Dissertation)
Dean Darnell
2008-01-23T23:59:59.000Z
The strangeness contribution to the electric and magnetic properties of the nucleon has been under investigation experimentally for many years. Lattice Quantum Chromodynamics (LQCD) gives theoretical predictions of these measurements by implementing the continuum gauge theory on a discrete, mathematical Euclidean space-time lattice which provides a cutoff removing the ultra-violet divergences. In this dissertation we will discuss effective methods using LQCD that will lead to a better determination of the strangeness contribution to the nucleon properties. Strangeness calculations are demanding technically and computationally. Sophisticated techniques are required to carry them to completion. In this thesis, new theoretical and computational methods for this calculation such as twisted mass fermions, perturbative subtraction, and General Minimal Residual (GMRES) techniques which have proven useful in the determination of these form factors will be investigated. Numerical results of the scalar form factor using these techniques are presented. These results give validation to these methods in future calculations of the strange quark contribution to the electric and magnetic form factors.
Tracking down hyper-boosted top quarks
Larkoski, Andrew J; Selvaggi, Michele
2015-01-01T23:59:59.000Z
The identification of hadronically decaying heavy states, such as vector bosons, the Higgs, or the top quark, produced with large transverse boosts has been and will continue to be a central focus of the jet physics program at the Large Hadron Collider (LHC). At a future hadron collider working at an order-of-magnitude larger energy than the LHC, these heavy states would be easily produced with transverse boosts of several TeV. At these energies, their decay products will be separated by angular scales comparable to individual calorimeter cells, making the current jet substructure identification techniques for hadronic decay modes not directly employable. In addition, at the high energy and luminosity projected at a future hadron collider, there will be numerous sources for contamination including initial- and final-state radiation, underlying event, or pile-up which must be mitigated. We propose a simple strategy to tag such "hyper-boosted" objects that defines jets with radii that scale inversely proportion...
Gaining (Mutual) Information about Quark/Gluon Discrimination
Andrew J. Larkoski; Jesse Thaler; Wouter J. Waalewijn
2014-12-03T23:59:59.000Z
Discriminating quark jets from gluon jets is an important but challenging problem in jet substructure. In this paper, we use the concept of mutual information to illuminate the physics of quark/gluon tagging. Ideal quark/gluon separation requires only one bit of truth information, so even if two discriminant variables are largely uncorrelated, they can still share the same "truth overlap". Mutual information can be used to diagnose such situations, and thus determine which discriminant variables are redundant and which can be combined to improve performance. Using both parton showers and analytic resummation, we study a two-parameter family of generalized angularities, which includes familiar infrared and collinear (IRC) safe observables like thrust and broadening, as well as IRC unsafe variants like $p_T^D$ and hadron multiplicity. At leading-logarithmic (LL) order, the bulk of these variables exhibit Casimir scaling, such that their truth overlap is a universal function of the color factor ratio $C_A/C_F$. Only at next-to-leading-logarithmic (NLL) order can one see a difference in quark/gluon performance. For the IRC safe angularities, we show that the quark/gluon performance can be improved by combining angularities with complementary angular exponents. Interestingly, LL order, NLL order, Pythia 8, and Herwig++ all exhibit similar correlations between observables, but there are significant differences in the predicted quark/gluon discrimination power. For the IRC unsafe angularities, we show that the mutual information can be calculated analytically with the help of a nonperturbative "weighted-energy function", providing evidence for the complementarity of safe and unsafe observables for quark/gluon discrimination.
An Improved determination of the width of the top quark
Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; /Oklahoma U.; Acharya, Bannanje Sripath; /Tata Inst.; Adams, Mark Raymond; /Illinois U., Chicago; Adams, Todd; /Florida State U.; Alexeev, Guennadi D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls; Alverson, George O.; /Northeastern U.; Aoki, Masato; /Fermilab; Askew, Andrew Warren; /Florida State U. /Stockholm U.
2012-01-01T23:59:59.000Z
We present an improved determination of the total width of the top quark, {Lambda}{sub t}, using 5.4 fb{sup -1} of integrated luminosity collected by the D0 Collaboration at the Tevatron p{bar p} Collider. The total width {Lambda}{sub t} is extracted from the partial decay width {Lambda}(t {yields} Wb) and the branching fraction {Beta}(t {yields} Wb). {Lambda}(t {yields} Wb) is obtained from the t-channel single top quark production cross section and {Beta}(t {yields} Wb) is measured in t{bar t} events. For a top mass of 172.5 GeV, the resulting width is {Lambda}{sub t} = 2.00{sub -0.43}{sup +0.47} GeV. This translates to a top-quark lifetime of {tau}{sub t} = (3.29{sub -0.63}{sup +0.90}) x 10{sup -25} s. We also extract an improved direct limit on the CKM matrix element 0.81 < |V{sub tb}| {le} 1 at 95% C.L. and a limit of |V{sub tb'}| < 0.59 for a high mass fourth generation bottom quark assuming unitarity of the fourth generation quark mixing matrix.
Top quark mass measurement using the template method at CDF
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T [Helsinki Inst. of Phys.; Alvarez Gonzalez, B [Oviedo U.; Cantabria Inst. of Phys.; Amerio, S [INFN, Padua; Amidei, D [Michigan U.; Anastassov, A [Northwestern U.; Annovi, A [Frascati; Antos, J [Comenius U.; Apollinari, G [Fermilab; Appel, J A [Fermilab; Apresyan, A [Purdue U.; Arisawa, T [Waseda U.; Dubna, JINR
2011-06-03T23:59:59.000Z
We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tt? decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of pp? collisions at Tevatron with ?s = 1.96 TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decay in the lepton+jets channel, and a reconstructed top quark mass and mT2, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop = 172.1±1.1 (stat)±0.9 (syst) GeV/c2.
A new method for determining the quark-gluon vertex
A. C. Aguilar; D. Binosi; D. Ibañez; J. Papavassiliou
2015-04-07T23:59:59.000Z
We present a novel nonperturbative approach for calculating the form factors of the quark-gluon vertex, in a general covariant gauge. The key ingredient of this method is the exact all-order relation connecting the conventional quark-gluon vertex with the corresponding vertex of the background field method, which is Abelian-like. When this latter relation is combined with the standard gauge technique, supplemented by a crucial set of transverse Ward identities, it allows the approximate determination of the nonperturbative behavior of all twelve form factors comprising the quark-gluon vertex, for arbitrary values of the momenta. The actual implementation of this procedure is carried out in the Landau gauge, in order to make contact with the results of lattice simulations performed in this particular gauge. The most demanding technical aspect involves the calculation of certain (fully-dressed) auxiliary three-point functions, using lattice data as input for the gluon propagators appearing in their diagrammatic expansion. The numerical evaluation of the relevant form factors in three special kinematical configurations (soft gluon and quark symmetric limit, zero quark momentum) is carried out in detail, finding rather good agreement with the available lattice data. Most notably, a concrete mechanism is proposed for explaining the puzzling divergence of one of these form factors observed in lattice simulations.
Top quark mass measurement using the template method at CDF
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A; et al
2011-06-03T23:59:59.000Z
We present a measurement of the top quark mass in the lepton+jets and dilepton channels of tt? decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb-1 of pp? collisions at Tevatron with ?s = 1.96 TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the W decay in the lepton+jets channel, and amore »reconstructed top quark mass and mT2, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop = 172.1±1.1 (stat)±0.9 (syst) GeV/c2.« less
Sketching the pion's valence-quark generalised parton distribution
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Mezrag, C.; Chang, L.; Moutarde, H.; Roberts, C. D.; Rodríguez-Quintero, J.; Sabatié, F.; Schmidt, S. M.
2015-02-01T23:59:59.000Z
In order to learn effectively from measurements of generalised parton distributions (GPDs), it is desirable to compute them using a framework that can potentially connect empirical information with basic features of the Standard Model. We sketch an approach to such computations, based upon a rainbow-ladder (RL) truncation of QCD’s Dyson–Schwinger equations and exemplified via the pion’s valence dressed-quark GPD, Hv?(x, ?, t). Our analysis focuses primarily on ?=0, although we also capitalise on the symmetry-preserving nature of the RL truncation by connecting Hv?(x, ?=±1, t)with the pion’s valence-quark parton distribution amplitude. We explain that the impulse-approximation used hitherto to definemore »the pion’s valence dressed-quark GPD is generally invalid owing to omission of contributions from the gluons which bind dressed-quarks into the pion. A simple correction enables us to identify a practicable improvement to the approximation for Hv?(x, 0, t), expressed as the Radon transform of a single amplitude. Therewith we obtain results for Hv?(x, 0, t) and the associated impact-parameter dependent distribution, qv?(x, |b?|), which provide a qualitatively sound picture of the pion’s dressed-quark structure at a hadronic scale. We evolve the distributions to a scale ? = 2 GeV, so as to facilitate comparisons in future with results from experiment or other nonperturbative methods.« less
Top Quark Properties from Top Pair Events and Decays
Andrew G. Ivanov; for the CDF; Dzero Collaborations
2008-10-19T23:59:59.000Z
Over a decade since the discovery of the top quark we are still trying to unravel mysteries of the heaviest observed particle and learn more about its nature. The continuously accumulating statistics of CDF and Dzero data provide the means for measuring top quark properties with ever greater precision and the opportunity to search for signs of new physics that could be manifested through subtle deviations from the standard model in the production and decays of top quarks. In the following we present a slice of the rich program in top quark physics at the Fermilab Tevatron: measurements of the properties of top quark decays and searches for unusual phenomena in events with pair produced tops. In particular, we discuss the most recent and precise CDF and Dzero measurements of the transverse polarization of W bosons from top decays, branching ratios and searches for flavor-changing neutral current decays, decays into charged Higgs and invisible decays. These analyses correspond to integrated luminosities ranging from 0.9 to 2.7 inv. fb.
Top quark induced effective potential in a composite Higgs model
Maarten Golterman; Yigal Shamir
2015-05-13T23:59:59.000Z
We consider non-perturbative aspects of a composite Higgs model that serves as a prototype for physics beyond the Standard Model, in which a new strongly interacting sector undergoes chiral symmetry breaking, and generates the Higgs particle as a pseudo Nambu-Goldstone boson. In addition, the top quark couples linearly to baryons of the new strong sector, thereby becoming partially composite. We study the dynamics leading to the top quark Yukawa coupling as well as the top quark contribution to the effective potential for the Higgs, obtaining expressions for these couplings in terms of baryonic correlation functions in the underlying strongly interacting theory. We then show that a large-N limit exists in which the top quark contribution to the Higgs effective potential overcomes that of the weak gauge bosons, inducing electroweak symmetry breaking. The same large-N limit also suggests that the baryons that couple to the top quark may be relatively light. This composite Higgs model, and similar ones, can be studied on the lattice with the methods developed for lattice QCD.
Measurements of the top quark mass and decay width with the D0 detector
Ilchenko, Yuriy
2011-11-01T23:59:59.000Z
The top quark discovery in 1995 at Fermilab is one of the major proofs of the standard model (SM). Due to its unique place in SM, the top quark is an important particle for testing the theory and probing for new physics. This article presents most recent measurements of top quark properties from the D0 detector. In particular, the measurement of the top quark mass, the top antitop mass difference and the top quark decay width. The discovery of the top quark in 1995 confirmed the existence of a third generation of quarks predicted in the standard model (SM). Being the heaviest elementary particle known, the top quark appears to become an important particle in our understanding of the standard model and physics beyond it. Because of its large mass the top quark has a very short lifetime, much shorter than the hadronization time. The predicted lifetime is only 3.3 {center_dot} 10{sup -25}s. Top quark is the only quark whose properties can be studied in isolation. A Lorentz-invariant local Quantum Field Theory, the standard model is expected to conserve CP. Due to its unique properties, the top quark provides a perfect test of CPT invariance in the standard model. An ability to look at the quark before being hadronized allows to measure directly mass of the top quark and its antiquark. An observation of a mass difference between particle and antiparticle would indicate violation of CPT invariance. Top quark through its radiative loop correction to the W mass constrains the mass of the Higgs boson. A precise measurement of the top quark mass provides useful information to the search of Higgs boson by constraining its region of possible masses. Another interesting aspect is that the top quark's Yukawa coupling to the Higgs boson is very close to unity (0.996 {+-} 0.006). That implies it may play a special role in the electroweak symmetry breaking mechanism.
New analysis concerning the strange quark polarization puzzle
Elliot Leader; Alexander V. Sidorov; Dimiter B. Stamenov
2015-07-09T23:59:59.000Z
The fact that analyses of semi-inclusive deep inelastic scattering suggest that the polarized strange quark density $\\Delta s(x) + \\Delta \\bar{s}(x)$ is positive in the measured region of Bjorken x, whereas all analyses of inclusive deep inelastic scattering yield significantly negative values of this quantity, is known as the "strange quark polarization puzzle". We have analyzed the world data on inclusive deep inelastic scattering, including the COMPASS 2010 proton data on the spin asymmetries, and for the first time, the new extremely precise JLab CLAS data on the proton and deuteron spin structure functions. Despite allowing in our parametrization, for a possible sign change, our results confirm that the inclusive data yield significantly negative values for the polarized strange quark density.
Recent top quark production results from the Tevatron
Oleg Brandt
2015-04-18T23:59:59.000Z
In this article, I review recent measurements of the production of the top quark in $p\\bar p$ collisions at a centre-of-mass energy of $\\sqrt s=1.96$~TeV in Run II of the Fermilab Tevatron Collider, recorded by the CDF and D0 Collaborations. I will present the Tevatron combination of measurements of the $t\\bar t$ production cross section and its differential measurement, the first evidence for and observation of the production of single top quarks in the $s$-channel, as well the final Tevatron combination of the production of single top quarks the $s$- and $t$-channels. Furthermore, I will review the measurements of the forward-backward asymmetry in $t\\bar t$ events, which can be experimentally uniquely accessed in the $CP$-invariant $p\\bar p$ initial state at the Tevatron, and conclude with the measurements of this asymmetry in the $b\\bar b$ system.
Top-quark processes at NLO in production and decay
Campbell, John M.; Ellis, R.Keith
2012-04-01T23:59:59.000Z
We describe the implementation of top production and decay processes in the parton-level Monte Carlo program MCFM. By treating the top quark as being on-shell, we can factorize the amplitudes for top-pair production, s-channel single-top production, and t-channel single-top production into the product of an amplitude for production and an amplitude for decay. In this way we can retain all spin correlations. Both the production and the decay amplitudes are calculated consistently at next-to-leading order in alpha_s. The full dependence on the b-quark mass is also kept. Phenomenological results are presented for various kinematic distributions at the LHC and for the top quark forward-backward asymmetry at the Tevatron.
Electric-Magnetic Duality and the Heavy Quark Potential
M. Baker
1996-09-05T23:59:59.000Z
We use the assumption of electric-magnetic duality to express the heavy quark potential in QCD in terms of a Wilson Loop $W_{eff}(\\Gamma)$ determined by the dynamics of a dual theory which is weakly coupled at long distances. The classical approximation gives the leading contribution to $W_{eff}(\\Gamma)$ and yields a velocity dependent heavy quark potential which for large $R$ becomes linear in $R$, and which for small $R$ approaches lowest order perturbative QCD. The corresponding long distance interaction between color magnetic monopoles is governed by a Yukawa potential. As a consequence the magnetic interaction between the color magnetic moments of the quarks is exponentially damped. The semi-classical corrections to $W_{eff}(\\Gamma)$ due to fluctuations of the classical flux tube should lead to an effective string theory free from the conformal anomaly.
Measurement of the top quark mass in the dilepton channel
Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Agelou, M.; Aguilo, E.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Hefei, CUST /Andes U., Bogota /Charles U.
2006-09-01T23:59:59.000Z
We present a measurement of the top quark mass in the dilepton channel based on approximately 370 pb{sup -1} of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We employ two different methods to extract the top quark mass. We show that both methods yield consistent results using ensemble tests of events generated with the D0 Monte Carlo simulation. We combine the results from the two methods to obtain a top quark mass m{sub t} = 178.1 {+-} 8.2 GeV. The statistical uncertainty is 6.7 GeV and the systematic uncertainty is 4.8 GeV.
The effects of colored quark entropy on the bag pressure
Miller, David E
2004-01-01T23:59:59.000Z
We study the effects of the ground state entropy of colored quarks upon the bag pressure at low temperatures. The vacuum expectation values of the quark and gluon fields are used to express the interactions in QCD ground state in the limit of low temperatures and chemical potentials. Apparently, the inclusion of this entropy in the equation of state provides the hadron constituents with an additional heat which causes a decrease in the effective latent heat inside the hadronic bag and consequently decreases the non-perturbative bag pressure. We have considered two types of baryonic bags, $\\Delta$ and $\\Omega^-$. In both cases we have found that the bag pressure decreases with the temperature. On the other hand, when the colored quark ground state entropy is not considered, the bag pressure as conventionally believed remains constant for finite temperature.
Dilepton emission at temperature dependent baryonic quark-gluon plasma
S. Somorendro Singh; Yogesh Kumar
2012-08-04T23:59:59.000Z
A fireball of QGP is evoluted at temperature dependent chemical potential by a statistical model in the pionic medium. We study the dilepton emission rate at temperature dependent chemical potential (TDCP) from such a fireball of QGP. In this model, we take the dynamical quark mass as a finite value dependence on temparature and parametrization factor of the QGP evolution. The temperature and factor in quark mass enhance in the growth of the droplets as well as in the dilepton emission rates. The emission rate from the plasma shows dilepton spectrum in the intermediate mass region (IMR) of (1.0-4.0) GeV and its rate is observed to be a strong increasing function of the temperature dependent chemical potential for quark and antiquark annihilation.
Can quark effects be observed in intermediate heavy ion collisions?
D. T. da Silva; D. Hadjimichef
2003-09-18T23:59:59.000Z
In recent years a tentative description of the short-range part of hadron interactions with constituent quark interchange has been developed providing an alternative approach to meson physics. Quark interchange plays a role, for example, in the nucleon-nucleon ($NN$) phase-shifts and cross-section. In heavy ion collision simulations at intermediate energies one of the main features is the $NN$ cross-section in the collisional term, where in most cases it is an input adjusted to the free space value. In this paper we introduce the quark degrees of freedom to the $NN$ cross-section in the Vlasov-Uehling-Uhlenbeck (VUU) model and explore the possibility that these effects appear in the observables at lower energies.
Thermodynamics of an exactly solvable confining quark model
Guimaraes, M S; Palhares, L F
2015-01-01T23:59:59.000Z
The grand partition function of a model of confined quarks is exactly calculated at arbitrary temperatures and quark chemical potentials. The model is inspired by a softly BRST-broken version of QCD and possesses a quark mass function compatible with nonperturbative analyses of lattice simulations and Dyson-Schwinger equations. Even though the model is defined at tree level, we show that it produces a nontrivial and stable thermodynamic behaviour at any temperature or chemical potential. Results for the pressure, the entropy and the trace anomaly as a function of the temperature are qualitatively compatible with the effect of nonperturbative interactions as observed in lattice simulations. The finite density thermodynamics is also shown to contain nontrivial features, being far away from an ideal gas picture.
Direct Measurement of the Total Decay Width of the Top Quark
Gomez-Ceballos, Guillelmo
We present a measurement of the total decay width of the top quark using events with top-antitop quark pair candidates reconstructed in the final state with one charged lepton and four or more hadronic jets. We use the ...
Pion cloud and sea quark flavor asymmetry in the impact parameter...
Office of Scientific and Technical Information (OSTI)
Pion cloud and sea quark flavor asymmetry in the impact parameter representation Citation Details In-Document Search Title: Pion cloud and sea quark flavor asymmetry in the impact...
Quark tensor charge and electric dipole moment within the Schwinger-Dyson formalism
Nodoka Yamanaka; Takahiro M. Doi; Shotaro Imai; Hideo Suganuma
2014-12-18T23:59:59.000Z
We calculate the tensor charge of the quark in the QCD-like theory in the Landau gauge using the Schwinger-Dyson formalism. It is found that the dressed tensor charge of the quark is significantly suppressed against the bare quark contribution, and the result agrees qualitatively with the analyses in the collinear factorization approach and lattice QCD. We also analyze the quark confinement effect with the phenomenological strong coupling given by Richardson, and find that this contribution is small. We show that the suppression of the quark tensor charge is due to the superposition of the spin flip of the quark arising from the successive emission of gluons which dress the tensor vertex. We also consider the relation between the quark and the nucleon electric dipole moments by combining with the simple constituent quark model.
RG-Improved Predictions for Top-Quark Pair Production at
California at Santa Cruz, University of
RG-Improved Predictions for Top-Quark Pair Production at Hadron Colliders Matthias Neubert Johannes Threshold resummation for Higgs production Threshold resummation for top-quark pair production Valentin
Aufgabe S1 F10 Die Bauteile 1,2,3 sind gelenkig miteinander verbunden, in A und B gelagert und
Peters, Norbert
(E) = 0 Cy 8a + B 4a = 0 Cy = - 1 2 B M(D) = 0 Cy 2a - Cx 2a + Ay 4a = 0 Cx = Cy + 2Ay = - 1 2 B + 2Ay sin 4 - Cx cos 4 - Cy sin 4 Fy = 0 Q = +Ax sin 4 - Ay cos 4 - Cx sin 4 - Cy cos 4 M=0 Mb = Ax2a - Ay2a Schnittreaktionen im Schnitt unterhalb des Gelenkes (obige Formeln ohne Cx und Cy): Fx
Jet Multiplicity in Top-Quark Pair Events at CMS
A. Descroix for the CMS Collaboration
2014-11-11T23:59:59.000Z
The normalised differential top quark-antiquark production cross section is measured as a function of the jet multiplicity. Using a procedure to associate jets to decay products of the top quarks, the differential cross section of the ttbar production is determined as a function of the additional jet multiplicity. The fraction of events with no additional jets is measured as a function of the threshold required for the transverse momentum of the additional jet. The measurements are compared with predictions from perturbative quantum chromodynamics and no significant deviations are observed.
Measurements of the Top Quark Pair-Production Cross Section
Frank-Peter Schilling
2013-02-19T23:59:59.000Z
Measurements of the inclusive and differential cross section for the production of top quark pairs in proton-(anti)proton collision at center-of-mass energies of 1.96, 7.0 and 8.0 TeV are presented and compared with the latest theory predictions and Monte-Carlo models. In addition, first measurements of the production of top quark pairs in association with additional jets or with a boson are highlighted. All measurements are in good agreement with the Standard Model.
Relating quarks and leptons with the T7 flavour group
Bonilla, Cesar; Peinado, Eduardo; Valle, Jose W F
2014-01-01T23:59:59.000Z
In this letter we present a model for quarks and leptons based on T7 as flavour symmetry, predicting a canonical mass relation between charged leptons and down-type quarks proposed earlier. Neutrino masses are generated through a Type-I seesaw mechanism, with predicted correlations between the atmospheric mixing angle and neutrino masses. Compatibility with oscillation results lead to lower bounds for the lightest neutrino mass as well as for the neutrinoless double beta decay rates, even for normal neutrino mass hierarchy.
A computational system for lattice QCD with overlap Dirac quarks
Ting-Wai Chiu; Tung-Han Hsieh; Chao-Hsi Huang; Tsung-Ren Huang
2002-10-31T23:59:59.000Z
We outline the essential features of a Linux PC cluster which is now being developed at National Taiwan University, and discuss how to optimize its hardware and software for lattice QCD with overlap Dirac quarks. At present, the cluster constitutes of 30 nodes, with each node consisting of one Pentium 4 processor (1.6/2.0 GHz), one Gbyte of PC800 RDRAM, one 40/80 Gbyte hard disk, and a network card. The speed of this system is estimated to be 30 Gflops, and its price/performance ratio is better than $1.0/Mflops for 64-bit (double precision) computations in quenched lattice QCD with overlap Dirac quarks.
Baryon number fluctuation and the quark-gluon plasma
Lin, ZW; Ko, Che Ming.
2001-01-01T23:59:59.000Z
baryon number are also studied. DOI: 10.1103/PhysRevC.64.041901 PAC A new state of matter, the quark-gluon plasma, is ex- pected to be formed in heavy ion collisions at ultrarelativistic energies, such as at the Relativistic Heavy Ion Collider ~RHIC...! that has just begun its operation at the Brookhaven National Laboratory. Many observables have been proposed as possible signatures for the quark-gluon plasma phase dur- ing the collisions @1#, such as strangeness enhancement @2#, J/c suppression @3...
Effects of quark chemical equilibration on thermal photon elliptic flow
Akihiko Monnai
2014-12-25T23:59:59.000Z
Large hadronic elliptic flow $v_2$ is considered as an evidence for the existence of a strongly-coupled QGP fluid in high-energy heavy-ion collisions. On the other hand, direct photon $v_2$ has recently been found to be much larger than hydrodynamic estimations, which is recognized as "photon $v_2$ puzzle". In this study, I discuss the implication of late production of quarks in an initially gluon-rich medium because photons are coupled to quarks. Numerical analyses imply that thermal photon $v_2$ can be visibly enhanced. This indicates that interplay of equilibration processes and collective expansion would be important.
Prospects for b-quark production cross section measurements in pp collisions at the LHC
A. Sherstnev
2006-09-14T23:59:59.000Z
A brief review of theoretical and experimental aspects of $b$-quark production measurements at the LHC.
Usage Mining for the World Wide Web WenChen Hu, wenchen@cs.und.edu
Hu, Wen-Chen
Usage Mining for the World Wide Web WenChen Hu, wenchen@cs.und.edu Department of Computer Science@mail.tku.edu.tw Department of Information Engineering, Tamkang University, Tamsui, Taiwan ABSTRACT Web usage mining is used an overview and analysis of current Web usage mining technologies and systems. A Web usage mining system
Franz, Sven Oliver
Migrationsproblematik: Die Fallstudie Guatemala Inaugural-Dissertation zur Erlangung der Doktorwürde der Philosophischen migración es un delito."1 (Schriftzug an der Tür einer Hütte in einem Dorf Guatemalas) ,,Es gibt kein................................................................................. 44 3 Die Fallstudie Guatemala: Die Fluchtfolgen im Aufnahmeland Mexiko und die Reintegration
APuZAus Politik und Zeitgeschichte 10/2010 8. Mrz 2010
Franz, Sven Oliver
Millenniums- erklärung mit acht konkreten Millenni- umsentwicklungszielen (MEZ) an. 2 Diese bil- den seitdem Globalisierung und die weltweite Entwicklungspolitik. Die MEZ be- ziehen sich auf Aspekte der ökonomischen, so weltweiten Ent- wicklungspartnerschaft. 3 Die Verständigung auf die acht MEZ war ein großer Schritt
Buchmann, Erik
Awareness"4 Dr.-Ing. Erik Buchmann - Kapitel 9: Smart Environments Smart Environments das "Aware Home" vom Computing Smart Environments Erik Buchmann (buchmann@kit.edu) #12;IPD, Nachwuchsgruppe ,,Privacy Awareness"2 Dr.-Ing. Erik Buchmann - Kapitel 9: Smart Environments Inhalte und Lernziele dieses Kapitels Smart
Buchmann, Erik
Awareness"4 Dr.-Ing. Erik Buchmann - Kapitel 10: Smart Environments Smart Environments das "Aware Home" vom Computing Smart Environments Erik Buchmann (buchmann@kit.edu) #12;IPD, Nachwuchsgruppe ,,Privacy Awareness"2 Dr.-Ing. Erik Buchmann - Kapitel 10: Smart Environments Inhalte und Lernziele dieses Kapitels
On Path diagrams and Stirling permutations Institut fur Diskrete Mathematik und Geometrie
Kuba, Markus
On Path diagrams and Stirling permutations M. Kuba Institut fÂ¨ur Diskrete Mathematik und Geometrie of this article is to extend the notion of local types to k-Stirling permutations, establish a relation diagrams. In the case of the classical Stirling permutations, we give an alternative continued fraction
On Path diagrams and Stirling permutations Institut fur Diskrete Mathematik und Geometrie
Kuba, Markus
On Path diagrams and Stirling permutations M. Kuba Institut fÂ¨ur Diskrete Mathematik und Geometrie is to introduce the notion of local types in k-Stirling permutations, to relate these local types with nodes types, Stirling permutations, Increasing trees, local types, formal power series 2000 Mathematics Subject
NANOTECHNOLOGY CENTER Eine Partnerschaft in Nanotechnologie von IBM Research und ETH Zrich
Cachin, Christian
NANOTECHNOLOGY CENTER Eine Partnerschaft in Nanotechnologie von IBM Research und ETH Zürich and Rohrer Nanotechnology Center is part of a strategic partnership in nanosciences with ETH Zurich, one FACT SHEET Above: The campus of IBM Research - Zurich Right: The Binnig and Rohrer Nanotechnology
Passau, Universität
/5 Speicherabbildung ndimensionaler Arrays (a) LENr=UBr-LBr1 (b) LEN_PRODUCTk = el_size r=k1 n LENr (c) zeroth_element, LEN_PRODUCTk (1 k n)) BoundChecking (LBr , LENr ) (1 r n) #12;Struktur und Implementierung von
O. Goecke: Collective saving schemes LUH-Kolloquium ,,Versicherungs-und Finanzmathematik"
Weber, Stefan
1 O. Goecke: Collective saving schemes LUH-Kolloquium ,,Versicherungs- und Finanzmathematik" Insurance and Demography, Hannover 19.06.2014 Collective saving schemes and return smoothing mechanism Oskar Goecke Institut für Versicherungswesen Forschungsstelle FaRis FH Köln #12;2 O. Goecke: Collective saving
Kliniken und Notrufnummern / Clinics and Energency Numbers Area Code / Vorwahl: 06221
Heermann, Dieter W.
Kliniken und Notrufnummern / Clinics and Energency Numbers Area Code / Vorwahl: 06221 Klinik für Anästhesiologie Clinic for Aneasthesiology Im Neuenheimer Feld 110 56 63 51 Medizinische Klinik Medical Hospital area code) 110 Deutsches Rotes Kreuz Heidelberg Rescue service German red Cross Heidelberg 19222
Charm physics with physical light and strange quarks using domain wall fermions
Peter A. Boyle; Luigi Del Debbio; Nicolas Garron; Andreas Juttner; Ava Khamseh; Marina Marinkovic; Francesco Sanfilippo; Justus T. Tsang
2015-02-03T23:59:59.000Z
We present a study of charm physics using RBC/UKQCD 2+1 flavour physical point domain wall fermion ensembles for the light quarks as well as for the valence charm quark. After a brief motivation of domain wall fermions as a suitable heavy quark discretisation we will show first results for masses and matrix elements.
Nonperturbative study of the action parameters for anisotropic-lattice quarks
Foley, Justin; Cais, Alan O; Peardon, Mike; Ryan, Sinead M. [School of Mathematics, Trinity College, Dublin 2 (Ireland)
2006-01-01T23:59:59.000Z
A quark action designed for highly anisotropic-lattice simulations is discussed. The mass-dependence of the parameters in the action is studied and the results are presented. Applications of this action in studies of heavy quark quantities are described and results are presented from simulations at an anisotropy of six, for a range of quark masses from strange to bottom.
TRANSITION TEMPERATURE IN QCD WITH PHYSICAL LIGHT AND STRANGE QUARK MASSES.
KARSCH, F.
2006-11-14T23:59:59.000Z
We present results from a calculation of the transition temperature in QCD with two light (up, down) and one heavier (strange) quark mass as well as for QCD with three degenerate quark masses. Furthermore, we discuss first results from an ongoing calculation of the QCD equation of state with almost realistic light and strange quark masses.
CDF/ANAL/TOP/PUB/7680 Measurement of the Top Quark Mass using the Template Method
Quigg, Chris
CDF/ANAL/TOP/PUB/7680 Measurement of the Top Quark Mass using the Template Method in the Lepton, 2005) We report a measurement of the top quark mass in the lepton plus jets channel of tÂ¯t events from, which brings 138 tÂ¯t candidates separated into four subsamples. A top quark mass is reconstructed
CDF/PHYS/TOP/PUBLIC/7303 Measurement of the Top Quark Mass
Quigg, Chris
CDF/PHYS/TOP/PUBLIC/7303 Measurement of the Top Quark Mass using the Neutrino Weighting Algorithm the top quark mass using 46 t #22; t candidate events in which both W bosons from top quarks decay events according to the t #22; t decay hypothesis and we measure a top mass of 170:6 +7:1 6:6 (stat) #6
CDF/PUB/TOP/CDFR/11076 First Search for s-channel Electroweak Single Top Quark
Quigg, Chris
CDF/PUB/TOP/CDFR/11076 First Search for s-channel Electroweak Single Top Quark Production, 2014) Abstract The first search for electroweak single top quark production from the exchange of an s-model backgrounds is observed. Assuming that this excess is due to electroweak production of top quarks of mass 172
THE TOP QUARK Updated December 2011 by T.M. Liss (Univ. Illinois) and A.
1 THE TOP QUARK Updated December 2011 by T.M. Liss (Univ. Illinois) and A. Quadt (Univ. G¨ottingen). A. Introduction: The top quark is the Q = 2/3, T3 = +1/2 member of the weak-isospin doublet" for more information). This note summarizes the properties of the top quark (mass, production cross section
FREE QUARK SEARCHES The basis for much of the theory of particle scattering and
to "unglue" quarks. Accelerator searches at increasing energies have pro- duced no evidence for free quarks 1 FREE QUARK SEARCHES The basis for much of the theory of particle scattering and hadron as free particles but are confined to mesons and baryons. Experiments show that it is at best difficult
Strandberg, Jonas; /Stockholm U.
2006-04-01T23:59:59.000Z
This thesis presents two measurements of the to pquark using 230 pb{sup -1} of data recorded with the D0 detector at the Tevatron accelerator. The first measurement determines the top pair production cross section at {radical}s = 1.96 TeV in proton-antiproton collisions. In the standard model of particle physics the top quark decays almost exclusively into a W boson and a b quark. Candidate events are selected by requiring that at least one jet in the event is tagged with the secondary vertex algorithm.
Hyperon Puzzle, Hadron-Quark Crossover and Massive Neutron Stars
Masuda, Kota; Takatsuka, Tatsuyuki
2015-01-01T23:59:59.000Z
Bulk properties of cold and hot neutron stars (NSs) are studied on the basis of the hadron-quark crossover picture where a smooth transition from the hadronic phase to the quark phase takes place at finite baryon density. By using a phenomenological equation of state (EOS) "CRover" which interpolates the two phases at around 3 times the nuclear matter density, it is found that the cold NSs with the gravitational mass larger than 2-solarmass can be sustained. This is in sharp contrast to the case of the first-order hadron-quark transition. The radii of the cold NSs with the CRover EOS are in the narrow range which is insensitive to the NS masses. Due to the stiffening of the EOS induced by the hadron-quark crossover, the central density of the NSs is at most 4 times the nuclear matter density and the hyperon-mixing barely occurs inside the NS core. This constitutes a solution of the long-standing hyperon puzzle. The effect of color superconductivity (CSC) on the NS structures is also examined with the hadron-q...
Top quark and higgs physics at the tevatron
Yao, WeiMing
2004-10-01T23:59:59.000Z
This is a writeup of my lectures given at the International Workshop on Frontiers of High Energy Physics, held at CCAST, Beijing, China during July 2-10. I discuss some basic experimental techniques for studying the Top quark and Higgsboson at the Tevatron, and review some recent results from CDF and D0 and their future prospects.
Hypercentral Constituent Quark Model with a Meson Cloud
D. Y. Chen; Y. B. Dong; M. M. Giannini; E. Santopinto
2006-11-07T23:59:59.000Z
The results for the elastic nucleon form factors and the electromagnetic transition amplitudes to the Delta(1232) resonance, obtained with the Hypercentral Constituent Quark Model with the inclusion of a meson cloud correction are briefly presented. The pion cloud effects are explicitly discussed.
Weak interactions of quarks and leptons: experimental status
Wojcicki, S.
1984-09-01T23:59:59.000Z
The present experimental status of weak interactions is discussed with emphasis on the problems and questions and on the possible lines of future investigations. Major topics include; (1) the quark mixing matrix, (2) CP violation, (3) rare decays, (4) the lepton sector, and (5) right handed currents. 118 references. (WHK)
A top quark mass measurement using a matrix element method
Linacre, Jacob Thomas; /Oxford U.
2010-02-01T23:59:59.000Z
A measurement of the mass of the top quark is presented, using top-antitop pair (t{bar t}) candidate events for the lepton+jets decay channel. The measurement makes use of Tevatron p{bar p} collision data at centre-of-mass energy {radical}s = 1.96 TeV, collected at the CDF detector. The top quark mass is measured by employing an unbinned maximum likelihood method where the event probability density functions are calculated using signal (t{bar t}) and background (W+jets) matrix elements, as well as a set of parameterised jet-to-parton mapping functions. The likelihood function is maximised with respect to the top quark mass, the fraction of signal events, and a correction to the jet energy scale (JES) of the calorimeter jets. The simultaneous measurement of the JES correction ({Delta}{sub JES}) provides an in situ jet energy calibration based on the known mass of the hadronically decaying W boson. Using 578 lepton+jets candidate events corresponding to 3.2 fb{sup -1} of integrated luminosity, the top quark mass is measured to be m{sub t} = 172.4 {+-} 1.4 (stat+{Delta}{sub JES}) {+-} 1.3 (syst) GeV=c{sup 2}, one of the most precise single measurements to date.
Direct Top-Quark Width Measurement at CDF
Bauer, Gerry P.
We present a measurement of the top-quark width in the lepton+jets decay channel of tt? events produced in pp? collisions at Fermilab’s Tevatron collider and collected by the CDF II detector. From a data sample corresponding ...
Hadron production from quark coalescence and jet fragmentation
Greco, V.; Ko, Che Ming; Vitev, I.
2005-01-01T23:59:59.000Z
Transverse momentum spectra of pions, protons, and antiprotons in Au+Au collisions at intermediate RHIC energy root s(NN)=62 GeV are studied in a model that includes both quark coalescence from the dense partonic matter and fragmentation...
Compact stars in a SU(3) Quark-Meson Model
Andreas Zacchi; Rainer Stiele; Juergen Schaffner-Bielich
2015-06-05T23:59:59.000Z
The recent observations of the massive pulsars PSR J1614-2230 and of PSR J0348+0432 with about two solar masses implies strong constraints on the properties of dense matter in the core of compact stars. Effective models of QCD aiming to describe neutron star matter can thereby be considerably constrained. In this context, a chiral quark-meson model based on a SU(3) linear $\\sigma$-model with a vacuum pressure and vector meson exchange is discussed in this work. The impact of its various terms and parameters on the equation of state and the maximum mass of compact stars are delineated to check whether pure quark stars with two solar masses are feasible within this approach. Large vector meson coupling constant and a small vacuum pressure allow for maximum masses of two or more solar masses. However, pure quark stars made of absolutely stable strange quark matter, so called strange stars, turn out to be restricted to a quite small parameter range.
Compact stars in a SU(3) Quark-Meson Model
Zacchi, Andreas; Schaffner-Bielich, Juergen
2015-01-01T23:59:59.000Z
The recent observations of the massive pulsars PSR J1614-2230 and of PSR J0348+0432 with about two solar masses implies strong constraints on the properties of dense matter in the core of compact stars. Effective models of QCD aiming to describe neutron star matter can thereby be considerably constrained. In this context, a chiral quark-meson model based on a SU(3) linear $\\sigma$-model with a vacuum pressure and vector meson exchange is discussed in this work. The impact of its various terms and parameters on the equation of state and the maximum mass of compact stars are delineated to check whether pure quark stars with two solar masses are feasible within this approach. Large vector meson coupling constant and a small vacuum pressure allow for maximum masses of two or more solar masses. However, pure quark stars made of absolutely stable strange quark matter, so called strange stars, turn out to be restricted to a quite small parameter range.
J/Psi Production by Charm Quark Coalescence
D. E. Kahana; S. H. Kahana
2010-06-30T23:59:59.000Z
Production of $c\\bar c$ pairs in elementary hadron-hadron collisions is introduced in a simulation of relativistic heavy ion collisions. Coalescence of charmed quarks and antiquarks into various charmonium states is performed and the results are compared to PHENIX J$/\\psi$ Au+Au data. The $\\chi$ and $\\psi$' bound states must be included as well as the ground state J$/\\psi$, given the appreciable feeding from the excited states down to the J$/\\psi$ via gamma decays. Charmonium coalescence is found to take place at relatively late times: generally after $c$($\\bar c$)-medium interactions have ceased. Direct production of charmonia through hadron-hadron interactions, {\\it ie.} without explicit presence of charm quarks, occurring only at early times, is suppressed by collisions with comoving particles and accounts for some $\\sim 5\\%$ of the total J$/\\psi$ production. Coalescence is especially sensitive to the level of open charm production, scaling naively as $n_{c\\bar c}^2$. The J$/\\psi$ transverse momentum distribution is dependent on the charm quark transverse momentum distribution and early charm quark-medium interaction, thus providing a glimpse of the initial collision history.
Search for rare top-quark decays at the LHC
Veloso, Filipe; The ATLAS collaboration
2015-01-01T23:59:59.000Z
Flavour-changing neutral-current (FCNC) top quark decays are suppressed by the GIM mechanism, but are enhanced by BSM models. Any evidence for top-quark FCNC decays could be an evidence for new physics. Searches for the FCNC decays $t\\to qX$ where $X=Z,\\gamma,H,g$ and $q=u,c$ performed by the ATLAS and CMS Collaborations are presented. Data collected during 2011 and 2012 from proton-proton ($pp$) collisions at the LHC at a centre-of-mass energy of $\\sqrt{s}=7$ and 8 TeV, corresponding to integrated luminosities ranging from 2.1 fb$^{-1}$ to 25 fb$^{-1}$, are analysed. Top-quark pair-production events with one top quark decaying through the $t\\to qZ,q\\gamma,qH$ channels and the other through the dominant Standard Model mode $t\\to bW$ are considered as signal, as well as direct top production for the $t\\to qg$ channel. No evidence for FCNC signals are found and upper limits on the $t\\to qX$ branching ratios are set at 95\\% confidence level.
Gauge cooling in complex Langevin for QCD with heavy quarks
Erhard Seiler; Dénes Sexty; Ion-Olimpiu Stamatescu
2012-11-20T23:59:59.000Z
We employ a new method, "gauge cooling", to stabilize complex Langevin simulations of QCD with heavy quarks. The results are checked against results obtained with reweigthing; we find agreement within the estimated errors. The method allows us to go to previously unaccessible high densities.
Uncovering the single top: observation of electroweak top quark production
Benitez, Jorge Armando; /Michigan State U.
2009-08-01T23:59:59.000Z
The top quark is generally produced in quark and anti-quark pairs. However, the Standard Model also predicts the production of only one top quark which is mediated by the electroweak interaction, known as 'Single Top'. Single Top quark production is important because it provides a unique and direct way to measure the CKM matrix element V{sub tb}, and can be used to explore physics possibilities beyond the Standard Model predictions. This dissertation presents the results of the observation of Single Top using 2.3 fb{sup -1} of Data collected with the D0 detector at the Fermilab Tevatron collider. The analysis includes the Single Top muon+jets and electron+jets final states and employs Boosted Decision Tress as a method to separate the signal from the background. The resulting Single Top cross section measurement is: (1) {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.74{sub -0.74}{sup +0.95} pb, where the errors include both statistical and systematic uncertainties. The probability to measure a cross section at this value or higher in the absence of signal is p = 1.9 x 10{sup -6}. This corresponds to a standard deviation Gaussian equivalence of 4.6. When combining this result with two other analysis methods, the resulting cross section measurement is: (2) {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.94 {+-} 0.88 pb, and the corresponding measurement significance is 5.0 standard deviations.
Calculation of associated production of a top quark and a W ? at the LHC
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Cao, Qing-Hong; Berger, Edmond L.; Yu, Jiang-Hao; Yuan, C.-P.
2011-11-01T23:59:59.000Z
We investigate collider signatures of a top-philic W' model, in which the W' boson couples only to the third-generation quarks of the standard model. The main discovery channel for this W' is through associated production of the W' and top quark, yielding a top-quark pair plus an extra bottom-quark jet as a signal. We do a full simulation of the signal and relevant backgrounds. We develop a method of analysis that allows us to conclude that discovery of the W' is promising at the LHC despite large standard model backgrounds. Bottom-quark tagging of the extra jet is key to suppressing the backgrounds.
Osnabrück, Universität
Herr Dr. Carsten Bödecker Rechtswissenschaften Herr Dr. Klaus Brinkmann Rechtswissenschaften Rechtswissenschaften Herr Dr. Andreas Bauer ja ja Papier FESEM Seminar zum Familien und Erbrecht Rechtswissenschaften Herr KlausDieter Benner ja ja Papier FEVOR Kapitalmarktstrafrecht Rechtswissenschaften Herr Dr. Ge
Vormann, Matthias
In-situ measurement of ground impedances Von der Fakultät für Mathematik und Naturwissenschaften .............................................................................................22 Summary: In-situ impedance measurement.Definitions..........................................................................................................................11 VI.Surface impedance measurement methods
42 MaxPlanckForschung 2 | 11 Wir Menschen sprechen nicht nur gerne und viel, wir tun
Falge, Eva
beeinflusst. Im Hypothalamus unterdrückt Insulin den Forschern zufolge bei fettreicher Ernäh- rung das Hypothalamus überstimmen. Dies er- klärt möglicherweise, warum wir bei entsprechender Metabolism, 7. Juni 2011; Nature Neuro- science, 5. Juni 2011) Insulin im Mittelhirn und im Hypothalamus
Y. Maezawa; S. Aoki; S. Ejiri; T. Hatsuda; K. Kanaya; H. Ohno; T. Umeda
2009-11-02T23:59:59.000Z
The free energy between a static quark and an antiquark is studied by using the color-singlet Polyakov-line correlation at finite temperature. We perform simulations on $32^3 \\times 12$, 10, 8, 6, 4 lattices in the high temperature phase with the RG-improved gluon action and 2+1 flavors of the clover-improved Wilson quark action. Since the simulations are based on the fixed scale approach that the temperature can be varied without changing the spatial volume and renormalization factor, it is possible to investigate temperature dependence of the heavy-quark free energy without any adjustment of the overall constant. We find that, the heavy-quark free energies at short distance converge to the heavy-quark potential evaluated from the Wilson-loop operator at zero temperature, in accordance with the expected insensitivity of short distance physics to the temperature. At long distance, the heavy-quark free energies approach to twice the single-quark free energies, implying that the interaction between heavy quarks is screened. The Debye screening mass obtained from the long range behavior of the heavy-quark free energy is compared with results of the thermal perturbation theory and those of $N_f=2$ and $N_f=0$ lattice simulations.
Nonzero Mean Squared Momentum of Quarks in the Non-Perturbative QCD Vacuum
Li-Juan Zhou; Leonard S. Kisslinger; Wei-xing Ma
2010-04-21T23:59:59.000Z
The non-local vacuum condensates of QCD describe the distributions of quarks and gluons in the non-perturbative QCD vacuum. Physically, this means that vacuum quarks and gluons have nonzero mean-squared momentum, called virtuality. In this paper we study the quark virtuality which is given by the ratio of the local quark-gluon mixed vacuum condensate to the quark local vacuum condensate. The two vacuum condensates are obtained by solving Dyson-Schwinger Equations of a fully dressed quark propagator with an effective gluon propagator. Using our calculated condensates, we obtain the virtuality of quarks in the QCD vacuum state. Our numerical predictions differ from the other theoretical model calculations such as QCD sum rules, Lattice QCD and instanton models.
\\THE POOL OF QUARKS AND GLUONS" The protons and neutrons, which make up nuclei, are not elementary in a simpli#12;ed way as a pool with three balls (quarks) of di#11;erent colours. Quarks cannot escape from the proton in the same way as balls are kept inside the pool by the boundaries. The quarks move freely except
Neutral B-meson mixing from unquenched lattice QCD with domain-wall light quarks and static b-quarks
Conrado Albertus; Yasumichi Aoki; Peter A. Boyle; Norman H. Christ; Thomas T. Dumitrescu; Jonathan M. Flynn; Tomomi Ishikawa; Taku Izubuchi; Oleg Loktik; Christopher T. Sachrajda; Amarjit Soni; Ruth S. Van de Water; Jan Wennekers; Oliver Witzel
2010-01-12T23:59:59.000Z
We demonstrate a method for calculating the neutral B-meson decay constants and mixing matrix elements in unquenched lattice QCD with domain-wall light quarks and static b-quarks. Our computation is performed on the "2+1" flavor gauge configurations generated by the RBC and UKQCD Collaborations with a lattice spacing of a approx 0.11 fm (a^-1 = 1.729 GeV) and a lattice spatial volume of approximately (1.8 fm)^3. We simulate at three different light sea quark masses with pion masses down to approximately 430 MeV, and extrapolate to the physical quark masses using a phenomenologically-motivated fit function based on next-to-leading order heavy-light meson SU(2) chiral perturbation theory. For the b-quarks, we use an improved formulation of the Eichten-Hill action with static link-smearing to increase the signal-to-noise ratio. We also improve the heavy-light axial current used to compute the B-meson decay constant to O(alpha_s p a) using one-loop lattice perturbation theory. We present initial results for the SU(3)-breaking ratios f_{B_s}/f_{B_d} and xi = f_{B_s} sqrt{B_{B_s}}/f_{B_d} sqrt{B_{B_d}}, thereby demonstrating the viability of the method. For the ratio of decay constants, we find f_{B_s}/f_{B_d} = 1.15(12) and for the ratio of mixing matrix elements, we find xi = 1.13(12), where in both cases the errors reflect the combined statistical and systematic uncertainties, including an estimate of the size of neglected O(1/m_b) effects.
Photon production from gluon mediated quark-anti-quark annihilation at confinement
Sarah Campbell
2015-06-20T23:59:59.000Z
Heavy ion collisions at RHIC produce direct photons at low transverse momentum, $p_{T}$ from 1-3 GeV/c, in excess of the $p$$+$$p$ spectra scaled by the nuclear overlap factor, $T_{AA}$. These low $p_{T}$ photons have a large azimuthal anisotropy, $v_{2}$. Theoretical models, including hydrodynamic models, struggle to quantitatively reproduce the large low $p_{T}$ direct photon excess and $v_{2}$ in a self-consistent manner. This paper presents a description of the low $p_{T}$ photon flow as the result of increased photon production from soft-gluon mediated $q$-$\\bar{q}$ interactions as the system becomes color-neutral. This production mechanism will generate photons that follow constituent quark number, $n_{q}$, scaling of $v_{2}$ with an $n_{q}$ value of two for direct photons. $\\chi^{2}$ comparisons of the published PHENIX direct photon and identified particle $v_{2}$ measurements finds that $n_{q}$-scaling applied to the direct photon $v_{2}$ data prefers the value $n_{q}=1.8$ and agrees with $n_{q}=2$ within errors in most cases. The 0-20% and 20-40% Au$+$Au direct photon data are compared to a coalescence-like Monte Carlo simulation that calculates the direct photon $v_{2}$ while describing the shape of the direct photon $p_{T}$ spectra in a consistent manner. The simulation, while systematically low compared to the data, is in agreement with the Au$+$Au measurement at $p_{T}photons will follow the modified $n_{q}$-scaling laws seen in identified hadron $v_{n}$ with an $n_{q}$ value of two.
Photon production from gluon mediated quark-anti-quark annihilation at confinement
Sarah Campbell
2015-04-07T23:59:59.000Z
Heavy ion collisions at RHIC produce direct photons at low transverse momentum, $p_{T}$ from 1-3 GeV/c, in excess of the $p$$+$$p$ spectra scaled by the nuclear overlap factor, $T_{AA}$. These low $p_{T}$ photons have a large azimuthal anisotropy, $v_{2}$. Theoretical models, including hydrodynamic models, struggle to quantitatively reproduce the large low $p_{T}$ direct photon excess and $v_{2}$ in a self-consistent manner. This paper presents a description of the low $p_{T}$ photon flow as the result of increased photon production from soft-gluon mediated $q$-$\\bar{q}$ interactions as the system becomes color-neutral. This production mechanism will generate photons that follow constituent quark number, $n_{q}$, scaling of $v_{2}$ with an $n_{q}$ value of two for direct photons. $\\chi^{2}$ comparisons of the published PHENIX direct photon and identified particle $v_{2}$ measurements finds that $n_{q}$-scaling applied to the direct photon $v_{2}$ data prefers the value $n_{q}=1.8$ and agrees with $n_{q}=2$ within errors in most cases. The 0-20\\% and 20-40\\% Au$+$Au direct photon data are compared to a coalescence-like Monte Carlo simulation that calculates the direct photon $v_{2}$ while describing the shape of the direct photon $p_{T}$ spectra in a consistent manner. The simulation, while systematically low, is in agreement with the Au$+$Au measurement at $p_{T}<3$ GeV/c in both centrality bins. Furthermore, this model predicts that higher order flow harmonics, $v_{n}$, in direct photons will follow the $n_{q}$-scaling laws seen in identified hadron $v_{n}$ with an $n_{q}$ value of approximately two.
Taylor, Frank E.
A search is reported for the pair production of a new quark b? with at least one b? decaying to a Z boson and a bottom quark. The data, corresponding to 2.0??fb[superscript -1] of integrated luminosity, were collected from ...
Taylor, Frank E.
This Letter presents a search for singly produced vector-like quarks, Q, coupling to light quarks, q. The search is sensitive to both charged current (CC) and neutral current (NC) processes, pp?Qq?Wqq? and pp?Qq?Zqq' with ...
WHOT-QCD Collaboration; :; Y. Maezawa; N. Ukita; S. Aoki; S. Ejiri; T. Hatsuda; N. Ishii; K. Kanaya
2007-02-13T23:59:59.000Z
We study Polyakov loop correlations and spatial Wilson loop at finite Temperature in two-flavor QCD simulations with the RG-improved gluon action and the clover-improved Wilson quark action on a $ 16^3 \\times 4$ lattice. From the line of constant physics at $m_{\\rm PS}/m_{\\rm V}=0.65$ and 0.80, we extract the heavy-quark free energies, the effective running coupling $g_{\\rm eff}(T)$ and the Debye screening mass $m_D(T)$ for various color channels of heavy quark--quark and quark--anti-quark pairs above the critical temperature. The free energies are well approximated by the screened Coulomb form with the appropriate Casimir factors at high temperature. The magnitude and the temperature dependence of the Debye mass are compared to those of the next-to-leading order thermal perturbation theory and to a phenomenological formula in terms of $g_{\\rm eff}(T)$. We make a comparison between our results with the Wilson quark action and the previous results with the staggered quark action. The spatial string tension is also studied in the high temperature phase and is compared to the next-to-next-leading order prediction in an effective theory with dimensional reduction.
Y. Maezawa; T. Umeda; S. Aoki; S. Ejiri; T. Hatsuda; K. Kanaya; H. Ohno
2012-10-24T23:59:59.000Z
Free energies between static quarks and Debye screening masses in the quark-gluon plasma are studied on the basis of Polyakov-line correlations in lattice simulations of 2+1 flavors QCD with the renormalization-group improved gluon action and the $O(a)$-improved Wilson quark action. We perform simulations at $m_{\\rm PS}/m_{\\rm V} = 0.63$ (0.74) for light (strange) flavors with lattice sizes of $32^3 \\times N_t$ with $N_t=4$--12. We adopt the fixed-scale approach, where temperature can be varied without changing the spatial volume and renormalization factor. We find that, at short distance, the free energies of static quarks in color-singlet channel converge to the static-quark potential evaluated from the Wilson-loop at zero-temperature, in accordance with the expected insensitivity of short distance physics to the temperature. At long distance, the free energies of static quarks approach to twice the single-quark free energies, implying that the interaction between static quarks is fully screened. The screening properties can be well described by the screened Coulomb form with appropriate Casimir factor at high temperature. We also discuss a limitation of the fixed-scale approach at high temperature.
Measurements of the top quark mass at the tevatron
Brandt, Oleg
2012-01-01T23:59:59.000Z
The mass of the top quark (\\mtop) is a fundamental parameter of the standard model (SM). Currently, its most precise measurements are performed by the CDF and D0 collaborations at the Fermilab Tevatron $p\\bar p$ collider at a centre-of-mass energy of $\\sqrt s=1.96 \\TeV$. We review the most recent of those measurements, performed on data samples of up to 8.7 \\fb\\ of integrated luminosity. The Tevatron combination using up to 5.8 fb$^{-1}$ of data results in a preliminary world average top quark mass of $m_{\\rm top} = 173.2 \\pm 0.9$ GeV. This corresponds to a relative precision of about 0.54%. We conclude with an outlook of anticipated precision the final measurement of \\mtop at the Tevatron.
Measurements of the top quark mass at the tevatron
Oleg Brandt; for the CDF Collaboration; for the D0 Collaboration
2012-04-04T23:59:59.000Z
The mass of the top quark (\\mtop) is a fundamental parameter of the standard model (SM). Currently, its most precise measurements are performed by the CDF and D0 collaborations at the Fermilab Tevatron $p\\bar p$ collider at a centre-of-mass energy of $\\sqrt s=1.96 \\TeV$. We review the most recent of those measurements, performed on data samples of up to 8.7 \\fb\\ of integrated luminosity. The Tevatron combination using up to 5.8 fb$^{-1}$ of data results in a preliminary world average top quark mass of $m_{\\rm top} = 173.2 \\pm 0.9$ GeV. This corresponds to a relative precision of about 0.54%. We conclude with an outlook of anticipated precision the final measurement of \\mtop at the Tevatron.
NLO evolution of 3-quark Wilson loop operator
I. Balitsky; A. V. Grabovsky
2014-08-15T23:59:59.000Z
It is well known that high-energy scattering of a meson from some hadronic target can be described by the interaction of that target with a color dipole formed by two Wilson lines corresponding to fast quark-antiquark pair. Moreover, the energy dependence of the scattering amplitude is governed by the evolution equation of this color dipole with respect to rapidity. Similarly, the energy dependence of scattering of a baryon can be described in terms of evolution of a three-Wilson-lines operator with respect to the rapidity of the Wilson lines. We calculate the evolution of the 3-quark Wilson loop operator in the next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. We also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.
Fourth generation quark mass limits in CKM-element space
Christian J. Flacco; Daniel Whiteson; Matthew Kelly
2011-01-25T23:59:59.000Z
We present a reanalysis of CDF data to extend limits on individual fourth-generation quark masses from particular flavor-mixing rates to the entire space of possible mixing values. Measurements from CDF have set individual limits on masses, $m_{b'}$ and $m_{t'}$, at the level of $335$--$385$ GeV assuming specific and favorable flavor-mixing rates. We consider the space of possible values for the mixing rates and find that the CDF data imply limits of $290$ GeV and greater over a wide range of mixing scenarios. We also analyze the limits from the perspective of a four-generation CKM matrix. We find that present experimental constraints on CKM elements do not suggest further constraints on fourth-generation quark masses.
The SF running coupling with four flavours of staggered quarks
P. Perez-Rubio; S. Sint
2007-10-03T23:59:59.000Z
In order to study the running coupling in four-flavour QCD, we review the set-up of the Schr\\"odinger functional (SF) with staggered quarks. Staggered quarks require lattices which, in the usual counting, have even spatial lattice extent $L/a$ while the time extent $T/a$ must be odd. Setting $T=L$ is therefore only possible up to ${\\rm O}(a)$, which introduces different cutoff effects already in the pure gauge theory. We re-define the SF such as to cope with this situation and determine the corresponding classical background field. A perturbative calculation yields the coefficient of the pure gauge ${\\rm O}(a)$ boundary counterterm to one-loop order.
Forward-backward asymmetry in top quark-antiquark production
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Abazov, Victor Mukhamedovich [Dubna, JINR; Abbott, Braden Keim [Oklahoma U.; Acharya, Bannanje Sripath [Tata Inst.; Adams, Mark Raymond [Illinois U., Chicago; Adams, Todd [Florida State U.; Alexeev, Guennadi D [Dubna, JINR; Alkhazov, Georgiy D [St. Petersburg, INP; Alton, Andrew K [Michigan U.; Augustana Coll., Sioux Falls; Alverson, George O [Northeastern U.; Alves, Gilvan Augusto [Rio de Janeiro, CBPF; Aoki, Masato [Fermilab; Louisiana Tech. U.
2011-12-12T23:59:59.000Z
We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a dataset corresponding to an integrated luminosity of 5.4 fb-1, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 ± 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 ± 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 ± 4.0)%. The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.
NLO evolution of 3-quark Wilson loop operator
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Balitsky, I.; Grabovsky, A. V.
2015-01-01T23:59:59.000Z
It is well known that high-energy scattering of a meson from some hadronic target can be described by the interaction of that target with a color dipole formed by two Wilson lines corresponding to fast quark-antiquark pair. Moreover, the energy dependence of the scattering amplitude is governed by the evolution equation of this color dipole with respect to rapidity. Similarly, the energy dependence of scattering of a baryon can be described in terms of evolution of a three-Wilson-lines operator with respect to the rapidity of the Wilson lines. We calculate the evolution of the 3-quark Wilson loop operator in themore »next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. We also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.« less
Angular correlations in top quark decays in standard model extensions
Batebi, S. [Science and Research Branch, Islamic Azad University (IAU), Tehran (Iran, Islamic Republic of); Etesami, S. M. [School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Physics Department, Isfahan University of Technology (IUT), P.O. Box 11365-9161, Isfahan (Iran, Islamic Republic of); Mohammadi-Najafabadi, M. [Physics Department, Isfahan University of Technology (IUT), P.O. Box 11365-9161, Isfahan (Iran, Islamic Republic of)
2011-03-01T23:59:59.000Z
The CMS Collaboration at the CERN LHC has searched for the t-channel single top quark production using the spin correlation of the t-channel. The signal extraction and cross section measurement rely on the angular distribution of the charged lepton in the top quark decays, the angle between the charged lepton momentum and top spin in the top rest frame. The behavior of the angular distribution is a distinct slope for the t-channel single top (signal) while it is flat for the backgrounds. In this Brief Report, we investigate the contributions which this spin correlation may receive from a two-Higgs doublet model, a top-color assisted technicolor (TC2) and the noncommutative extension of the standard model.
Meson mass splittings in unquenched quark models (EEF70)
T. J. Burns
2014-11-10T23:59:59.000Z
General results are obtained for meson mass splittings and mixings in unquenched (coupled-channel) quark models. Theorems derived previously in perturbation theory are generalised to the full coupled-channel system. A new formula is obtained for the mass splittings of physical states in terms of the splittings of the valence states. The S-wave hyperfine splitting decreases due to unquenching, but its relation to the vector $e^+e^-$ width is unchanged; this yields a prediction for the missing $\\eta_b(3S)$. The ordinary (quenched) quark model result that the P-wave hyperfine splitting vanishes also survives unquenching. A ratio of mass splittings used to discriminate quarkonium potential models is scarcely affected by unquenching.
NLO evolution of 3-quark Wilson loop operator
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Balitsky, Ian [ODU, JLAB; Grabovsky, A V [Novosibirsk
2015-01-01T23:59:59.000Z
It is well known that high-energy scattering of a meson from some hadronic target can be described by the interaction of that target with a color dipole formed by two Wilson lines corresponding to fast quark-antiquark pair. Moreover, the energy dependence of the scattering amplitude is governed by the evolution equation of this color dipole with respect to rapidity. Similarly, the energy dependence of scattering of a baryon can be described in terms of evolution of a three-Wilson-lines operator with respect to the rapidity of the Wilson lines. We calculate the evolution of the 3-quark Wilson loop operator in the next-to-leading order (NLO) and present a quasi-conformal evolution equation for a composite 3-Wilson-lines operator. We also obtain the linearized version of that evolution equation describing the amplitude of the odderon exchange at high energies.
Forward-backward asymmetry in top quark-antiquark production
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D; Alkhazov, Georgiy D; Alton, Andrew K; Alverson, George O; Alves, Gilvan Augusto; et al
2011-12-12T23:59:59.000Z
We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a dataset corresponding to an integrated luminosity of 5.4 fb-1, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 ± 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 ± 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 ± 4.0)%.more »The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.« less
Energy profile of b-jet for boosted top quarks
Yoshio Kitadono
2014-09-05T23:59:59.000Z
We analyse the semileptonic decay of a polarised top-quark with a large velocity based on the perturbative QCD factorisation framework. Thanks to the factorisation and the spin decomposition, the production part and the decay part can be factorised and the spin dependence is introduced in the decay part. The decay part is converted to the top-jet function which describes the distribution of jet observables and the spin is translated to the helicity of the boosted top. Using this top-jet function, the energy profile of b-jet is investigated and it is turned out that the sub-jet energy for the helicity-minus top is accumulated faster than that for the helicity-plus top. This behaviour for the boosted top can be understood with the negative spin-analysing-power of b-quark in the polarised-top decay.
Thermal axion production in the primordial quark-gluon plasma
Graf, Peter; Steffen, Frank Daniel [Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany)
2011-04-01T23:59:59.000Z
We calculate the rate for thermal production of axions via scattering of quarks and gluons in the primordial quark-gluon plasma. To obtain a finite result in a gauge-invariant way that is consistent to leading order in the strong gauge coupling, we use systematic field theoretical methods such as hard thermal loop resummation and the Braaten-Yuan prescription. The thermally produced yield, the decoupling temperature, and the density parameter are computed for axions with a mass below 10 meV. In this regime, with a Peccei-Quinn scale above 6x10{sup 8} GeV, the associated axion population can still be relativistic today and can coexist with the axion cold dark matter condensate.
Thermal axion production in the primordial quark-gluon plasma
Peter Graf; Frank Daniel Steffen
2011-04-20T23:59:59.000Z
We calculate the rate for thermal production of axions via scattering of quarks and gluons in the primordial quark-gluon plasma. To obtain a finite result in a gauge-invariant way that is consistent to leading order in the strong gauge coupling, we use systematic field theoretical methods such as hard thermal loop resummation and the Braaten-Yuan prescription. The thermally produced yield, the decoupling temperature, and the density parameter are computed for axions with a mass below 10 meV. In this regime, with a Peccei-Quinn scale above 6x10^8 GeV, the associated axion population can still be relativistic today and can coexist with the axion cold dark matter condensate.
Measurements of the top quark mass at the Tevatron
Brandt, Oleg; /Gottingen U., II. Phys. Inst.
2012-04-01T23:59:59.000Z
The mass of the top quark (m{sub top}) is a fundamental parameter of the standard model (SM). Currently, its most precise measurements are performed by the CDF and D0 collaborations at the Fermilab Tevatron p{bar p} collider at a centre-of-mass energy of {radical}s = 1.96 TeV. We review the most recent of those measurements, performed on data samples of up to 8.7 fb{sup -1} of integrated luminosity. The Tevatron combination using up to 5.8 fb{sup -1} of data results in a preliminary world average top quark mass of m{sub top} = 173.2 {+-} 0.9 GeV. This corresponds to a relative precision of about 0.54%. We conclude with an outlook of anticipated precision the final measurement of m{sub top} at the Tevatron.
Cavitation from bulk viscosity in neutron stars and quark stars
Jes Madsen
2009-09-30T23:59:59.000Z
The bulk viscosity in quark matter is sufficiently high to reduce the effective pressure below the corresponding vapor pressure during density perturbations in neutron stars and strange stars. This leads to mechanical instability where the quark matter breaks apart into fragments comparable to cavitation scenarios discussed for ultra-relativistic heavy-ion collisions. Similar phenomena may take place in kaon-condensed stellar cores. Possible applications to compact star phenomenology include a new mechanism for damping oscillations and instabilities, triggering of phase transitions, changes in gravitational wave signatures of binary star inspiral, and astrophysical formation of strangelets. At a more fundamental level it points to the possible inadequacy of a hydrodynamical treatment of these processes in compact stars.
Forward-backward asymmetry in top quark-antiquark production
Abazov, Victor Mukhamedovich [Dubna, JINR; Abbott, Braden Keim [Oklahoma U.; Acharya, Bannanje Sripath [Tata Inst.; Adams, Mark Raymond [Illinois U., Chicago; Adams, Todd [Florida State U.; Alexeev, Guennadi D [Dubna, JINR; Alkhazov, Georgiy D [St. Petersburg, INP; Alton, Andrew K [Michigan U.; Augustana Coll., Sioux Falls; Alverson, George O [Northeastern U.; Alves, Gilvan Augusto [Rio de Janeiro, CBPF; Aoki, Masato [Fermilab; Louisiana Tech. U.
2011-12-12T23:59:59.000Z
We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a dataset corresponding to an integrated luminosity of 5.4 fb^{-1}, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 ± 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 ± 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 ± 4.0)%. The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.
Why should we care about the top quark Yukawa coupling?
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Shapshnikov, Mikhail; Bezrukov, Fedor
2015-03-01T23:59:59.000Z
In the cosmological context, for the Standard Model to be valid up to the scale of inflation, the top quark Yukawa coupling yt should not exceed the critical value ytcrit , coinciding with good precision (about 0.2‰) with the requirement of the stability of the electroweak vacuum. So, the exact measurements of yt may give an insight on the possible existence and the energy scale of new physics above 100 GeV, which is extremely sensitive to yt. We overview the most recent theoretical computations of and the experimental measurements of ytcrit and the experimental measurements of yt. Within themore »theoretical and experimental uncertainties in yt, the required scale of new physics varies from 10? GeV to the Planck scale, urging for precise determination of the top quark Yukawa coupling.« less
Lattice studies of hadron physics with disconnected quark loops
Takashi Kaneko
2010-12-13T23:59:59.000Z
Disconnected diagrams give crucial contributions to the physics of flavor singlet hadrons and to scalar form factors of non-singlet hadrons. Naive lattice calculation of the disconnected diagrams, however, requires a huge number of fermion matrix inversions and hence a prohibitively large computational cost. In this article, we present recent studies of the flavor-singelt meson spectrum and nucleon strange quark content using the all-to-all propagator to calculate the relevant disconnected diagrams.
Transverse momentum dependent quark densities from Lattice QCD
Bernhard Musch,Philipp Hagler,John Negele,Andreas Schafer
2011-02-01T23:59:59.000Z
We study transverse momentum dependent parton distribution functions (TMDs) with non-local operators in lattice QCD, using MILC/LHPC lattices. Results obtained with a simpli?ed operator geometry show visible dipole de- formations of spin-dependent quark momentum densities. We discuss the basic concepts of the method, including renormalization of the gauge link, and an ex- tension to a more elaborate operator geometry that would allow us to analyze process-dependent TMDs such as the Sivers-function.
Non-perturbative Heavy Quark Effective Theory: Introduction and Status
Rainer Sommer
2015-01-13T23:59:59.000Z
We give an introduction to Heavy Quark Effective Theory (HQET). Our emphasis is on its formulation non-perturbative in the strong coupling, including the non-perturbative determination of the parameters in the HQET Lagrangian. In a second part we review the present status of HQET on the lattice, largely based on work of the ALPHA collaboration in the last few years. We finally discuss opportunities and challenges.
The static quark potential for dynamical domain wall fermion simulations
Min Li
2006-10-18T23:59:59.000Z
We present preliminary results for the static quark potential computed on some of the DWF lattice configurations generated by the RBC-UKQCD collaborations. Most of these results were obtained using Wilson lines joining spatial planes fixed into the Coulomb gauge. We compare the results from this method with the earlier ones on $16^3 \\times 32$ lattices using Bresenham spatial paths with APE smeared link variables. Some preliminary results on $24^3 \\times 64$ lattices are also presented.
Top quark physics and QCD: Progress since the TESLA TDR
A. Brandenburg
2003-09-08T23:59:59.000Z
I review progress on investigations concerning top quark physics and QCD at a future linear e+e- collider that has been achieved since the presentation of the TESLA technical design report in spring 2001. I concentrate on studies that have been presented during the workshop series of the Extended Joint ECFA/DESY Study on Physics and Detectors for a Linear Electron-Positron Collider.
Measurement of the Top Quark Mass With 2012 CMS Data
Richard Nally
2014-09-01T23:59:59.000Z
The mass of the top quark was an active topic of research at CMS using 2011 data, and remains so as the 2012 data analysis campaign proceeds. Here we discuss some of the earliest results on the top mass using 2012 sqrt(s) = 8 TeV CMS data, including measurements of the top mass from semileptonic t\\bar{t} decays and the lifetime of the B-hadron, as well as a measurement of the top-antitop mass difference.
Statistical Understanding of Quark and Lepton Masses in Gaussian Landscapes
Lawrence J. Hall; Michael P. Salem; Taizan Watari
2007-08-10T23:59:59.000Z
The fundamental theory of nature may allow a large landscape of vacua. Even if the theory contains a unified gauge symmetry, the 22 flavor parameters of the Standard Model, including neutrino masses, may be largely determined by the statistics of this landscape, and not by any symmetry. Then the measured values of the flavor parameters do not lead to any fundamental symmetries, but are statistical accidents; their precise values do not provide any insights into the fundamental theory, rather the overall pattern of flavor reflects the underlying landscape. We investigate whether random selection from the statistics of a simple landscape can explain the broad patterns of quark, charged lepton, and neutrino masses and mixings. We propose Gaussian landscapes as simplified models of landscapes where Yukawa couplings result from overlap integrals of zero-mode wavefunctions in higher-dimensional supersymmetric gauge theories. In terms of just five free parameters, such landscapes can account for all gross features of flavor, including: the hierarchy of quark and charged lepton masses; small quark mixing angles, with 13 mixing less than 12 and 23 mixing; very light Majorana neutrino masses, with the solar to atmospheric neutrino mass ratio consistent with data; distributions for leptonic 12 and 23 mixings that are peaked at large values, while the distribution for 13 mixing is peaked at low values; and order unity CP violating phases in both the quark and lepton sectors. While the statistical distributions for flavor parameters are broad, the distributions are robust to changes in the geometry of the extra dimensions. Constraining the distributions by loose cuts about observed values leads to narrower distributions for neutrino measurements of 13 mixing, CP violation, and neutrinoless double beta decay.
Sommer 2011 Erstellt am: 26. September 2011 Fakultt fr Mathematik, Physik und Informatik
Dettweiler, Michael
Sommer 2011 Erstellt am: 26. September 2011 Seite 1 FakultÃ¤t fÃ¼r Mathematik, Physik und Informatik:00 - 10:00 woch NW II - S 79 Bauer-Catanese,Ingrid Fragestunde zur Linearen Algebra II #12;Sommer 2011,Wolfgang Di 08:00 - 10:00 woch NW II - H 19 Neidhardt,Wolfgang #12;Sommer 2011 Erstellt am: 26. September 2011
Fachgebiet Leistungselektronik und Elektrische Antriebstechnik Prof. Dr.-Ing. J. Bcker
Paderborn, Universität
Pos.1 Pos.2 iC C R iR u(t) Zum Zeitpunkt t = 0 werde der Schalter S von Position 1 in Position 2 Elektrische Antriebstechnik Prof. Dr.-Ing. J. Böcker Pos.2 12T1T t0T 13T Schalter- stellung Pos.1 12T1T t0T 13 und Elektrische Antriebstechnik Prof. Dr.-Ing. J. Böcker Aufgabe 4: RL-Reihenschaltung S U0 Pos.1 Pos
The B*Bpi coupling using relativistic heavy quarks
J. M. Flynn; P. Fritzsch; T. Kawanai; C. Lehner; B. Samways; C. T. Sachrajda; R. S. Van de Water; O. Witzel; for the RBC/UKQCD Collaboration
2015-06-21T23:59:59.000Z
We report on a calculation of the B*Bpi coupling in lattice QCD. The strong matrix element for a B* to Bpi transition is directly related to the leading order low-energy constant in heavy meson chiral perturbation theory (HMChPT) for B mesons. We carry out our calculation directly at the b-quark mass using a non-perturbatively tuned clover action that controls discretization effects of order pa and (ma)^n for all n. Our analysis is performed on RBC/UKQCD gauge configurations using domain-wall fermions and the Iwasaki gauge action at two lattice spacings of ainverse = 1.729(25) GeV, ainverse = 2.281(28) GeV, and unitary pion masses down to 290 MeV. We achieve good statistical precision and control all systematic uncertainties, giving a final result for the HMChPT coupling g_b = 0.56(3)stat(7)sys in the continuum and at the physical light-quark masses. This is the first calculation performed directly at the physical b-quark mass and lies in the region one would expect from carrying out an interpolation between previous results at the charm mass and at the static point.
The $B^*B?$ coupling with relativistic heavy quarks
J. M. Flynn; P. Fritzsch; T. Kawanai; C. Lehner; C. T. Sachrajda; B. Samways; R. S. Van de Water; O. Witzel
2013-11-10T23:59:59.000Z
We report on a calculation of the $B^*B\\pi$ coupling in lattice QCD. The strong matrix element $\\langle B \\pi | B^*\\rangle$ is directly related to the leading order low-energy constant in heavy meson chiral perturbation theory (HM$\\chi$PT) for $B$-mesons. We carry out our calculation directly at the $b$-quark mass using a non-perturbatively tuned clover action that controls discretisation effects of order $|\\vec{p}a|$ and $(ma)^n$ for all $n$. Our analysis is performed on RBC/UKQCD gauge configurations using domain wall fermions and the Iwasaki gauge action at two lattice spacings of $a^{-1}=1.73(3)$ GeV, $a^{-1}=2.28(3)$ GeV, and unitary pion masses down to 290 MeV. We achieve good statistical precision and control all systematic uncertainties, giving a final result for the HM$\\chi$PT coupling $g_b = 0.569(48)_{stat}(59)_{sys}$ in the continuum and at the physical light-quark masses. This is the first calculation performed directly at the physical $b$-quark mass and lies in the region one would expect from carrying out an interpolation between previous results at the charm mass and at the static point.
Top quark anomalous couplings at the International Linear Collider
Erik Devetak; Andrei Nomerotski; Michael Peskin
2011-07-27T23:59:59.000Z
We present a study of the experimental determination of the forward-backward asymmetry in the process $e^+e^-\\to t\\bar t$ and in the subsequent $t\\to Wb$ decay, studied in the context of the International Linear Collider. This process probes the elementary couplings of the top quark to the photon, the $Z$ and the $W$ bosons at a level of precision that is difficult to achieve at hadron colliders. Measurement of the forward-backward asymmetry requires excellent $b$ quark identification and determination of the quark charge. The study reported here is performed in the most challenging all-hadronic channel $e^+e^- \\to b\\bar b q\\bar q q\\bar q$. It includes realistic details of the experimental environment, a full Monte Carlo simulation of the detector, based on the Silicon Detector concept, and realistic event reconstruction. The forward-backward asymmetries are determined to a precision of approximately 1% for each of two choices of beam polarization. We analyze the implications for the determination of the $t\\bar t Z$ and $Wtb$ couplings.
Numerical Simulation of the Hydrodynamical Combustion to Strange Quark Matter
Brian Niebergal; Rachid Ouyed; Prashanth Jaikumar
2010-08-27T23:59:59.000Z
We present results from a numerical solution to the burning of neutron matter inside a cold neutron star into stable (u,d,s) quark matter. Our method solves hydrodynamical flow equations in 1D with neutrino emission from weak equilibrating reactions, and strange quark diffusion across the burning front. We also include entropy change due to heat released in forming the stable quark phase. Our numerical results suggest burning front laminar speeds of 0.002-0.04 times the speed of light, much faster than previous estimates derived using only a reactive-diffusive description. Analytic solutions to hydrodynamical jump conditions with a temperature dependent equation of state agree very well with our numerical findings for fluid velocities. The most important effect of neutrino cooling is that the conversion front stalls at lower density (below approximately 2 times saturation density). In a 2-dimensional setting, such rapid speeds and neutrino cooling may allow for a flame wrinkle instability to develop, possibly leading to detonation.
The B*Bpi coupling using relativistic heavy quarks
Flynn, J M; Kawanai, T; Lehner, C; Samways, B; Sachrajda, C T; Van de Water, R S; Witzel, O
2015-01-01T23:59:59.000Z
We report on a calculation of the B*Bpi coupling in lattice QCD. The strong matrix element for a B* to Bpi transition is directly related to the leading order low-energy constant in heavy meson chiral perturbation theory (HMChPT) for B mesons. We carry out our calculation directly at the b-quark mass using a non-perturbatively tuned clover action that controls discretization effects of order pa and (ma)^n for all n. Our analysis is performed on RBC/UKQCD gauge configurations using domain-wall fermions and the Iwasaki gauge action at two lattice spacings of ainverse = 1.729(25) GeV, ainverse = 2.281(28) GeV, and unitary pion masses down to 290 MeV. We achieve good statistical precision and control all systematic uncertainties, giving a final result for the HMChPT coupling g_b = 0.56(3)stat(7)sys in the continuum and at the physical light-quark masses. This is the first calculation performed directly at the physical b-quark mass and lies in the region one would expect from carrying out an interpolation between ...
The Fluid Nature of Quark-Gluon Plasma
W. A. Zajc
2008-02-25T23:59:59.000Z
Collisions of heavy nuclei at very high energies offer the exciting possibility of experimentally exploring the phase transformation from hadronic to partonic degrees of freedom which is predicted to occur at several times normal nuclear density and/or for temperatures in excess of $\\sim 170$ MeV. Such a state, often referred to as a quark-gluon plasma, is thought to have been the dominant form of matter in the universe in the first few microseconds after the Big Bang. Data from the first five years of heavy ion collisions of Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) clearly demonstrate that these very high temperatures and densities have been achieved. While there are strong suggestions of the role of quark degrees of freedom in determining the final-state distributions of the produced matter, there is also compelling evidence that the matter does {\\em not} behave as a quasi-ideal state of free quarks and gluons. Rather, its behavior is that of a dense fluid with very low kinematic viscosity exhibiting strong hydrodynamic flow and nearly complete absorption of high momentum probes. The current status of the RHIC experimental studies is presented, with a special emphasis on the fluid properties of the created matter, which may in fact be the most perfect fluid ever studied in the laboratory.
Local Gauge Transformation for the Quark Propagator in an SU(N) Gauge Theory
Aslam, M Jamil; Gutierrez-Guerrero, L X
2015-01-01T23:59:59.000Z
In an SU(N) gauge field theory, the n-point Green functions, namely, propagators and vertices, transform under the simultaneous local gauge variations of the gluon vector potential and the quark matter field in such a manner that the physical observables remain invariant. In this article, we derive this intrinsically non perturbative transformation law for the quark propagator within the system of covariant gauges. We carry out its explicit perturbative expansion till O(g_s^6) and, for some terms, till O(g_s^8). We study the implications of this transformation for the quark-anti-quark condensate, multiplicative renormalizability of the massless quark propagator, as well as its relation with the quark-gluon vertex at the one-loop order. Setting the color factors C_F=1 and C_A=0, Landau-Khalatnikov-Fradkin transformation for the abelian case of quantum electrodynamics is trivially recovered.
QCD with light Wilson quarks on fine lattices (I): first experiences and physics results
L. Del Debbio; L. Giusti; M. Lüscher; R. Petronzio; N. Tantalo
2006-10-09T23:59:59.000Z
Recent conceptual, algorithmic and technical advances allow numerical simulations of lattice QCD with Wilson quarks to be performed at significantly smaller quark masses than was possible before. Here we report on simulations of two-flavour QCD at sea-quark masses from slightly above to approximately 1/4 of the strange-quark mass, on lattices with up to 64x32^3 points and spacings from 0.05 to 0.08 fm. Physical sea-quark effects are clearly seen on these lattices, while the lattice effects appear to be quite small, even without O(a) improvement. A striking result is that the dependence of the pion mass on the sea-quark mass is accurately described by leading-order chiral perturbation theory up to meson masses of about 500 MeV.
CDF/ANAL/TOP/PUB/7153 Measurement of the Top Quark Mass using the Template Method
Quigg, Chris
CDF/ANAL/TOP/PUB/7153 Measurement of the Top Quark Mass using the Template Method in the Lepton of the top quark mass in the lepton plus jets channel of t #22; t events from p#22;p collisions at p s = 1; t candidates with at least one identi#12;ed b jet. A top quark mass is reconstructed for each event by using
Search of anomalous $Wtb$ couplins in single top quark prodution at D0
Joshi, Jyoti; Beri, Suman; /Panjab U.
2011-12-01T23:59:59.000Z
The large mass of the top quark, close to the electroweak symmetry-breaking scale, makes it a good candidate for probing physics beyond the Standard Model, including possible anomalous couplings. D0 has made measurements of single top quark production using 5.4 fb{sup -1} of integrated luminosity. We examine the data to study the Lorentz structure of the Wtb coupling. We find that the data prefer the left-handed vector coupling and set upper limits on the anomalous couplings. In 2009, the electroweak single top quark production was observed by the D0 and CDF collaborations. Electroweak production of top quarks at the Tevatron proceeds mainly via the decay of a time-like virtual W boson accompanied by a bottom quark in the s-channel (tb = t{bar b} + {bar t}b), or via the exchange of a space-like virtual W boson between a light quark and a bottom quark in the t-channel (tqb = tq{bar b} + {bar t}qb, where q refers to the light quark). For a top quark mass of 172.5 GeV, The Standard Model (SM) prediction of single top production rate at next-to-leading order with soft-gluon contributions at next-to-next-to-leading order are 1.04 {+-} 0.04 pb (s-channel) and 2.26 {+-} 0.12 pb (t-channel). The large mass of the top quark implies that it has large couplings to the electroweak symmetry breaking sector of the SM and may have non-standard interactions with the weak gauge bosons. Single top quark production provides a unique probe to study the interactions of the top quark with the W boson.
An analysis of 4-quark energies in SU(2) lattice Monte Carlo
Sadataka Furui; Bilal Masud
1998-09-12T23:59:59.000Z
Energies of four-quark systems with the tetrahedral geometry measured by the static quenched SU(2) lattice Monte Carlo method are analyzed by parametrizing the gluon overlap factor in the form exp(-[bs EA+{\\sqrt bs}FP]) where A and P are the area and the perimeter defined mainly by the positions of the four quarks, bs is the string constant in the 2-quark potentials and E, F are constants.
Medium Corrections to the Nucleon Electroweak Observables in a Light-Front Quark Model
Araujo, W.R.B. de; Suisso, E.F.; Batista, E.F.; Carlson, B.V.; Frederico, T. [Dep. de Fisica, Instituto Tecnologico de Aeronautica, Centro Tecnico Aeroespacial, 12.228-900 Sao Jose dos Campos, Sao Paulo (Brazil)
2004-12-02T23:59:59.000Z
We study the nuclear medium effects on the proton electromagnetic form factor ratio GEp/GMp within a light-front constituent quark model with different quark spin coupling schemes and momentum components of the wave functions. We compute only effects from the quark and nucleon in-medium masses. The effective masses are obtained from a relativistic {sigma} - {omega} self-consistent mean-field approximation of the nuclear matter within a quark-meson coupling model. Our calculation describes qualitatively the recent experimental data.
Gluon Radiation in Top Quark Production and Decay at $e^+e^-$ Colliders
Cosmin Macesanu; Lynne H. Orr
2000-12-18T23:59:59.000Z
We study gluon radiation in top quark production above threshold at high energy $e^+e^-$ colliders. We allow for the top quarks to be off-shell, considering radiation in both the top production and decay processes simultaneously. Our calculation includes all top width effects, spin correlations, and $b$ quark mass effects. We study the effects of gluon radiation on top mass reconstuction and examine the interference between production- and decay-stage radiation, which can be sensitive to the value of the top quark decay width.
Four-quark energies in SU(2) lattice Monte Carlo using a tetrahedral geometry
A. M. Green; J. Lukkarinen; P. Pennanen; C. Michael; S. Furui
1994-12-05T23:59:59.000Z
This contribution -- a continuation of earlier work -- reports on recent developments in the calculation and understanding of 4-quark energies generated using lattice Monte Carlo techniques.
Tomography of a quark gluon plasma at RHIC and LHC energies
P. B. Gossiaux; R. Bierkandt; J. Aichelin
2009-03-23T23:59:59.000Z
Using the recently published model for the collisional energy loss of heavy quarks (Q) in a Quark Gluon Plasma (QGP), based on perturbative QCD (pQCD) with a running coupling constant, we study the interaction between heavy quarks and plasma particles in detail. We discuss correlations between the simultaneously produced $c$ and $\\bar{c}$ quarks, study how central collisions can be experimentally selected, predict observable correlations and extend our model to the energy domain of the large hadron collider (LHC). We finally compare the predictions of our model with that of other approaches like AdS/CFT.
Measurement of the top quark mass with dilepton events selected using neuroevolution at CDF
CDF Collaboration; T. Aaltonen
2009-04-14T23:59:59.000Z
We report a measurement of the top quark mass $M_t$ in the dilepton decay channel $t\\bar{t}\\to b\\ell'^{+}\
M. M. Giannini
2015-06-19T23:59:59.000Z
The predictions of the hypercentral Consituent Quark Model for the nucleon helicity amplitudes are briefly reported. Some future perspectives are also discussed.
Improving the Top Quark Forward-Backward Asymmetry Measurement at the LHC
Bai, Yang; /SLAC; Han, Zhenyu; /Harvard U., Phys. Dept.
2011-08-15T23:59:59.000Z
At the LHC, top quark pairs are dominantly produced from gluons, making it difficult to measure the top quark forward-backward asymmetry. To improve the asymmetry measurement, we study variables that can distinguish between top quarks produced from quarks and those from gluons: the invariant mass of the top pair, the rapidity of the top-antitop system in the lab frame, the rapidity of the top quark in the top-antitop rest frame, the top quark polarization and the top-antitop spin correlation. We combine all the variables in a likelihood discriminant method to separate quark-initiated events from gluon-initiated events. We apply our method on models including G-prime's and W-prime's motivated by the recent observation of a large top quark forward-backward asymmetry at the Tevatron. We have found that the significance of the asymmetry measurement can be improved by 10% to 30%. At the same time, the central values of the asymmetry increase by 40% to 100%. We have also analytically derived the best spin quantization axes for studying top quark polarization as well as spin-correlation for the new physics models.
Exotic Physics with the Top Quark at the LHC. End of grant report
Black, Kevin
2013-07-29T23:59:59.000Z
The grant supported two main activities : searching for new physics with the top quark at the LHC and development of the ATLAS muon trigger.
Charm Quark Energy Loss In Infinite QCD Matter Using A Parton Cascade Model
Mohammed Younus; Christopher E. Coleman-Smith; Steffen A. Bass; Dinesh K. Srivastava
2015-01-27T23:59:59.000Z
We utilize the Parton Cascade Model to study the evolution of charm quarks propagating through a thermal brick of QCD matter. We determine the energy loss and the transport coefficient '$\\hat{q}$' for charm quarks. The calculations are done at a constant temperature of 350 MeV and the results are compared to analytical calculations of heavy quark energy loss in order to validate the applicability of using a Parton Cascade Model for the study of heavy quarks dynamics in hot and dense QCD matter.
Four-Quark Binding Energies from SU(2) Lattice Monte Carlo
A. M. Green; C. Michael; M. E. Sainio
1994-04-11T23:59:59.000Z
Energies of four-quark systems have been extracted in a static quenched SU(2) lattice Monte Carlo calculation for six different geometries, both planar and non-planar, with $\\beta=2.4$ and lattice size $16^3\\times 32$. In all cases, it is found that the binding energy is greatly enhanced when the four quarks can be partitioned in two ways with comparable energies. Also it is shown that the energies of the four-quark states cannot be understood simply in terms of two-quark potentials.
Baron, Frank
2009-01-01T23:59:59.000Z
Herausgegeben von Frank Baron In Verbindung mit einer kritischen Edition des Textes von 1585 von Benedikt Sommer Series: Studium Literarum 17 Publisher: Weidler Buchverlag Year: 2009... ---------------------------------------------------------------------------------------------------------------------------------- Table of Contents: Frank Baron, Einleitung (Introduction) I. Benedikt Sommer, Christlich bedencken und erjnnerung von Zauberey, kritische Edition II. Untersuchungen (Essays) Benedikt Sommer, Das Leben und Werk Hermann Witekinds Otto Ulbricht...
Arndt, Holger
20 Kombination von C++ und Java 20.1 Java Native Interface (JNI) 20-3 (364) 20.1 Java Native Interface (JNI) Der Standardweg zur Kombination von C++ und Java ist das Java Native Interface (JNI), das Bestandteil des JDK ist. 20.1.1 C++-Funktionen aus Java aufrufen Â· Gegeben sei die folgende kleine C
Arndt, Holger
20 Kombination von C++ und Java 20.1 Java Native Interface (JNI) 20-3(378) 20.1 Java Native Interface (JNI) Der Standardweg zur Kombination von C++ und Java ist das Java Native Interface (JNI), das Bestandteil des JDK ist. 20.1.1 C++-Funktionen aus Java aufrufen Â· Gegeben sei die folgende kleine C
Arndt, Holger
20 Kombination von C++ und Java 20.1 Java Native Interface (JNI) 20-3 (360) 20.1 Java Native Interface (JNI) Der Standardweg zur Kombination von C++ und Java ist das Java Native Interface (JNI), das Bestandteil des JDK ist. 20.1.1 C++-Funktionen aus Java aufrufen Â· Gegeben sei die folgende kleine C
Lin, Huey-Wen; Cohen, Saul; Dudek, Jozef; Edwards, Robert; Joo, Balint; Richards, David; Bulava, John; Foley, Justin; Morningstar, Colin; Engelson, Eric; Wallace, Stephen; Juge, Jimmy; Mathur, Nilmani; Peardon, Michael; Ryan, Sinead
2009-02-01T23:59:59.000Z
We present the first light-hadron spectroscopy on a set of $N_f=2+1$ dynamical, anisotropic lattices. A convenient set of coordinates that parameterize the two-dimensional plane of light and strange-quark masses is introduced. These coordinates are used to extrapolate data obtained at the simulated values of the quark masses to the physical light and strange-quark point. A measurement of the Sommer scale on these ensembles is made and the performance of the hybrid Monte Carlo algorithm used for generating the ensembles is estimated.
Lin, H.-W.; Cohen, Saul D.; Dudek, Jozef; Edwards, Robert G.; Joo, Balint; Richards, David G. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Bulava, John; Foley, Justin; Morningstar, Colin [Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Engelson, Eric; Wallace, Stephen [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Juge, K. Jimmy [Department of Physics, University of the Pacific, Stockton, California 95211 (United States); Mathur, Nilmani [Department of Theoretical Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Peardon, Michael J.; Ryan, Sinead M. [School of Mathematics, Trinity College, Dublin 2 (Ireland)
2009-02-01T23:59:59.000Z
We present the first light-hadron spectroscopy on a set of N{sub f}=2+1 dynamical, anisotropic lattices. A convenient set of coordinates that parameterize the two-dimensional plane of light and strange-quark masses is introduced. These coordinates are used to extrapolate data obtained at the simulated values of the quark masses to the physical light and strange-quark point. A measurement of the Sommer scale on these ensembles is made, and the performance of the hybrid Monte Carlo algorithm used for generating the ensembles is estimated.
Lepton and Quark Mixing Patterns from Finite Flavor Symmetries
Chang-Yuan Yao; Gui-Jun Ding
2015-05-14T23:59:59.000Z
We perform a systematical and analytical study of lepton mixing which can be derived from the subgroups of $SU(3)$ under the assumption that neutrinos are Dirac particles. We find that type D groups can predict lepton mixing patterns compatible with the experimental data at $3\\sigma$ level. The lepton mixing matrix turns out to be of the trimaximal form, and the Dirac CP violating phase is trivial. Moreover, we extend the flavor symmetry to the quark sector. The Cabibbo mixing between the first two generations of quarks can be generated by type D groups. Since all the finite subgroups of $U(3)$ which are not the subgroups of $SU(3)$ have not been classified, an exhaustive scan over all finite discrete groups up to order 2000 is performed with the help of the computer algebra system \\texttt{GAP}. We find that only 90 (10) groups for Dirac (Majorana) neutrinos can generate the lepton mixing angles in the experimentally preferred ranges. The lepton mixing matrix is still the trimaximal pattern and the Dirac CP phase remains trivial. The smallest groups which lead to viable mixing angles are $[162, 10]$, $[162, 12]$ and $[162, 14]$. For quark flavor mixing, the correct order of magnitude of the CKM matrix elements can not be generated. Only the Cabibbo mixing is allowed even if we impose very loose constraints $0.1\\leq|\\left(V_{CKM}\\right)_{12}|\\leq0.3$ and $|\\left(V_{CKM}\\right)_{13}|\\leq|\\left(V_{CKM}\\right)_{23}|right)_{12}|$. The group $\\Delta(6\\cdot7^2)$ can predict a Cabibbo angle $\\theta_q=\\pi/14$ in good agreement with the best fit value. The groups which can give rise to both phenomenologically viable lepton mixing angles and acceptable Cabibbo angle are discussed, and the groups $\\Delta(6\\cdot9^2)$, $[648, 259]$, $[648, 260]$, $[648, 266]$ and $\\Delta(6\\cdot14^2)$ are especially promising.
Measurements of heavy quark production via single leptons at PHENIX
Donald Hornback; for the PHENIX Collaboration
2008-04-30T23:59:59.000Z
The measurement of single leptons from the semi-leptonic decay of heavy-flavor hadrons has long been a means for studying heavy-quark production. PHENIX has measured single muons in pp collisions at forward rapidity and single electrons in both pp and AuAu collisions at mid-rapidity at sqrt(s_NN)=200 GeV. The most recent PHENIX single lepton results are presented in the context of state-of-the-art pQCD calculations. An updated azimuthal anisotropy, v2(pT), measurement for heavy-flavor single electrons in AuAu collisions is also presented.
Top quark pair production cross section at LHC in ATLAS
John David Morris
2014-10-24T23:59:59.000Z
Measurements of the top quark production cross section in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented. The measurements require no, one or two electrons or muons in the final state (single lepton, dilepton, hadronic channel). In addition, the decay modes with tau leptons are tested (channels with tau leptons). The main focus is on measurements of differential spectra of $t\\bar{t}$ final states, in particular, measurements that are able to constrain the modelling of additional parton radiation like the jet multiplicity distribution.
Anisotropic hydrodynamics for mixture of quark and gluon fluids
Florkowski, Wojciech; Ryblewski, Radoslaw; Tinti, Leonardo
2015-01-01T23:59:59.000Z
A system of equations for anisotropic hydrodynamics is derived that describes a mixture of anisotropic quark and gluon fluids. The consistent treatment of the zeroth, first and second moments of the kinetic equations allows us to construct a new framework with more general forms of the anisotropic phase-space distribution functions than those used before. In this way, the main difficiencies of the previous formulations of anisotropic hydrodynamics for mixtures have been overcome and the good agreement with the exact kinetic-theory results is obtained.
Measurement of the top quark mass in the dilepton channel
Baringer, Philip S.; Abbott, B.; Abolins, M.; Abramov, V.; Acharya, B. S.; Adam, I.; Adams, D. L.; Adams, M.; Ahn, S.; Aihara, H.
1999-07-14T23:59:59.000Z
radiative corrections, the value of the top quark mass affects predic- tions of the standard model for many processes. For ex- ample, the prediction for the mass of the W boson varies by approximately 7 MeV1 for every 1 GeV change in the mass of the top... subdetectors that measure the trajectories of charged par- ticles: a vertex drift chamber, a transition radiation detector, a central drift chamber, and two forward drift chambers. These chambers also measure ionization to identify tracks from single charged...
Dynamics of heavy flavor quarks in high energy nuclear collisions
Andrea Beraudo
2014-07-22T23:59:59.000Z
A general overview on the role of heavy quarks as probes of the medium formed in high energy nuclear collisions is presented. Experimental data compared to model calculations at low and moderate pT are exploited to extract information on the transport coefficients of the medium, on possible modifications of heavy flavor hadronization in a hot environment and to provide quantitative answers to the issue of kinetic (and chemical, at conceivable future experimental facilities) thermalization of charm. Finally, the role of heavy flavor at high pT as a tool to study the mass and color-charge dependence the jet quenching is also analyzed.
Quark Antiscreening at Strong Magnetic Field and Inverse Magnetic Catalysis
E. J. Ferrer; V. de la Incera; X. J. Wen
2015-02-17T23:59:59.000Z
The dependence of the QCD coupling constant with a strong magnetic field and the implications for the critical temperature of the chiral phase transition are investigated. It is found that the coupling constant becomes anisotropic in a strong magnetic field and that the quarks, confined by the field to the lowest Landau level where they pair with antiquarks, produce an antiscreening effect. These results lead to inverse magnetic catalysis, providing a natural explanation for the behavior of the critical temperature in the strong-field region.
Neutrons and Quarks Share Dual Nature | Jefferson Lab
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5(Million Cubic Feet) Oregon (Including Vehicle Fuel) (Million Cubic Feet) Natural Gas Delivered to WhatNeutrons and Quarks Share Dual Nature Mosiac
Gamma-Ray Bursts from Primordial Quark Objects in Space
B. Anoushirvani; D. Enström; S. Fredriksson; J. Hansson; P. Ökvist; A. Nicolaidis; S. Ekelin
1997-11-28T23:59:59.000Z
We investigate the possibility that gamma-ray bursts originate in a concentric spherical shell with a given average redshift and find that this is indeed compatible with the data from the third BATSE (3B) catalog. It is also shown that there is enough freedom in the choice of unknown burst properties to allow even for extremely large distances to the majority of bursts. Therefore, we speculate about an early, and very energetic, origin of bursts, and suggest that they come from phase transitions in massive objects of pure quark matter, left over from the Big Bang.
Measurement of the top quark mass at D0
Petrillo, Gianluca; /Rochester U.
2010-01-01T23:59:59.000Z
The most recent measurements of the mass of the quark top at D0 are reviewed. The analysis methods include the direct measurement by Matrix Element and Weighting method and the indirect measurement from t{bar t} production cross section. They have been applied on different experimental signatures, all including at least one electron or muon. Measurements include from 1 to 3.6 fb{sup -1} of D0 data. The most recent combination of mass measurements from D0 and from CDF are also quoted.
Quark mean-field theory and consistency with nuclear matter
Dey, J.; Tomio, L. (Instituto de Fisica Teorica, Universidade Estadual Paulista, Rua Pamplona 145, 01405 Sao Paulo (Brazil)); Dey, M. (Department of Physics, Maulana Azad College, Calcutta 700 013 (India)); Frederico, T. (Institute for Nuclear Theory, Department of Physics, FM-15, University of Washington, Seattle, Washington (USA))
1991-11-01T23:59:59.000Z
1/{ital N}{sub {ital c}} expansion in QCD (with {ital N}{sub {ital c}} the number of colors) suggests using a potential from meson sector (e.g., Richardson) for baryons. For light quarks a {sigma} field has to be introduced to ensure chiral symmetry breaking ({chi}SB). It is found that nuclear matter properties can be used to pin down the {chi}SB modeling. All masses, {ital M}{sub {ital N}}, {ital m}{sub {sigma}}, {ital m}{sub {omega}}, are found to scale with density. The equations are solved self-consistently.
Simulation of diffraction dissociation in quark-diquark representation
V. M. Grichine
2015-02-27T23:59:59.000Z
A low mass single diffraction dissociation mode based on the quark-diquark representation of hadron-nucleon interaction is proposed. The mass spectra of nucleon-pion system are compared with experimental data and predictions of other models. The hadron-nucleus single-diffraction cross-sections are calculated in the framework of the Glauber-Gribov model for integral cross-sections. The model predictions are compared with experimental data for the different distributions of secondary particles produced in the hadron-nucleus interactions in the momentum range 31-320 GeV/c.
J/psi Production in Quark-Gluon Plasma
Li Yan; Pengfei Zhuang; Nu Xu
2006-11-05T23:59:59.000Z
We study J/psi production at RHIC and LHC energies with both initial production and regeneration. We solve the coupled set of transport equation for the J/psi distribution in phase space and the hydrodynamic equation for evolution of quark-gluon plasma. At RHIC, continuous regeneration is crucial for the J/psi momentum distribution while the elliptic flow is still dominated by initial production. At LHC energy, almost all the initially created J\\psis are dissociated in the medium and regeneration dominates the J/psi properties.
Viscous quark-gluon plasma model through fluid QCD approach
Djun, T. P., E-mail: tpdjun@teori.fisika.lipi.go.id [Graduate Study in Material Science, University of Indonesia, Kampus UI Salemba, Jakarta 10430, Indonesia and Group for Theoretical and Computational Physics, Research Center for Physics, Indonesian Institute of Sciences, Kompleks Puspiptek Serpong, T (Indonesia); Soegijono, B.; Mart, T. [Graduate Study in Material Science, University of Indonesia, Kampus UI Salemba, Jakarta 10430, Indonesia and Department of Physics, University of Indonesia, Kampus UI Depok, Depok 16424 (Indonesia); Handoko, L. T., E-mail: Handoko@teorifisika.lipi.go.id, E-mail: Laksana.tri.handoko@lipi.go.id [Group for Theoretical and Computational Physics, Research Center for Physics, Indonesian Institute of Sciences, Kompleks Puspiptek Serpong, Tangerang 15310, Indonesia and Research Center for Informatics, Indonesia Institute of Sciences, Kompleks LIPI (Indonesia)
2014-09-25T23:59:59.000Z
A Lagrangian density for viscous quark-gluon plasma has been constructed within the fluid-like QCD framework. Gauge symmetry is preserved for all terms inside the Lagrangian, except for the viscous term. The transition mechanism from point particle field to fluid field, and vice versa, are discussed. The energy momentum tensor that is relevant to the gluonic plasma having the nature of fluid bulk of gluon sea is derived within the model. By imposing conservation law in the energy momentum tensor, shear viscosity appears as extractable from the equation.
Rephasing Invariants of Quark and Lepton Mixing Matrices
Elizabeth Jenkins; Aneesh V. Manohar
2007-11-14T23:59:59.000Z
Rephasing invariants of quark and lepton mixing matrices are obtained in the standard model extended by the seesaw mechanism, and in its low-energy effective theory with the dimension-five Majorana mass operator. We classify the basic invariants, discuss non-trivial relations between them, and determine the independent invariants which characterize all the information in the mixing matrices in a basis-independent way. We also discuss the restrictions on the allowed ranges for the mixing phases, and on the rephasing invariants, which follow from a discrete invariance of the Majorana mass matrix.
Multi-Quark Energies in SU(2) Lattice Gauge Theory
A. M. Green; C. Michael; J. E. Paton; M. E. Sainio
1993-01-15T23:59:59.000Z
Energies of four-quark systems have been extracted in a quenched SU(2) lattice Monte Carlo calculation for two different geometries, rectangular and colinear, with $\\beta=2.4$ and lattice size $16^3\\times 32$. Also, by going to a lattice $24^3\\times 32$ and to $\\beta=2.5$, the effect of the finite lattice size and scaling are checked. An attempt is made to understand these results in terms of a model based on interquark two-body potentials but modified very significantly by a phenomenological gluon-field overlap factor.
Maier, Andreas Alexander; The ATLAS collaboration
2015-01-01T23:59:59.000Z
The top quark mass in dileptonic top quark pair decays was measured using $4.7~\\mathrm{fb}^{-1}$ of $\\sqrt{s}=7~\\mathrm{TeV}$ proton-proton ($pp$) collision data recorded by the ATLAS experiment at the LHC in 2011. The event topology is characterised by the presence of two charged leptons, at least two neutrinos and several jets, two of which originate from bottom quarks. Using the template method and the m$_{\\ell b}$ observable, defined as the average invariant mass of the two charged lepton plus $b$-jet pairs in each event, the top quark mass is measured to be $173.09 \\pm 0.64~(\\mathrm{stat}) \\pm 1.50~(\\mathrm{syst})~\\mathrm{GeV}$. This proceeding is based on a preliminary result, which has been superseded meanwhile.
CDF/PUB/TOP/CDFR/11033 Updated Measurement of the Single Top Quark Production Cross1
Quigg, Chris
CDF/PUB/TOP/CDFR/11033 Updated Measurement of the Single Top Quark Production Cross1 Section in the form of a reconstructed jet.30 The first CDF measurement of electroweak single top quark production 1 URL http://www-cdf.fnal.gov5 (Dated: May 9, 2014)6 Abstract An updated measurement
Comment on "Texture Zeros and WB Transformations in the Quark Sector of the Standard Model"
Samandeep Sharma; Priyanka Fakay; Gulsheen Ahuja; Manmohan Gupta
2015-03-04T23:59:59.000Z
Recently, using specific Weak Basis transformations, Y. Giraldo [Phys. Rev. D 86, 093021 (2012)] has constructed some texture 5 and 4 zero quark mass matrices and examined their compatibility with the quark mixing data. In this comment, we have re-analyzed these to bring forth certain important issues regarding their viability which need to be taken note of.
Thermodynamics and quark susceptibilities: a Monte-Carlo approach to the PNJL model
Weise, Wolfram
Thermodynamics and quark susceptibilities: a Monte-Carlo approach to the PNJL model M on the thermodynamics of the model, both in the case of pure gauge theory and including two quark flavors. In the two- flavor case, we calculate the second-order Taylor expansion coefficients of the thermodynamic grand
Systematic analysis of the incoming quark energy loss in cold nuclear matter
Li-Hua Song; Chun-Gui Duan; Na Liu
2012-06-18T23:59:59.000Z
The investigation into the fast parton energy loss in cold nuclear matter is crucial for a good understanding of the parton propagation in hot-dense medium. By means of four typical sets of nuclear parton distributions and three parametrizations of quark energy loss, the parameter values in quark energy loss expressions are determined from a leading order statistical analysis of the existing experimental data on nuclear Drell-Yan differential cross section ratio as a function of the quark momentum fraction. It is found that with independence on the nuclear modification of parton distributions, the available experimental data from lower incident beam energy rule out the incident-parton momentum fraction quark energy loss. Whether the quark energy loss is linear or quadratic with the path length is not discriminated. The global fit of all selected data gives the quark energy loss per unit path length {\\alpha} = 1.21\\pm0.09 GeV/fm by using nuclear parton distribution functions determined only by means of the world data on nuclear structure function. Our result does not support the theoretical prediction: the energy loss of an outgoing quark is three times larger than that of an incoming quark approaching the nuclear medium. It is desirable that the present work can provide useful reference for the Fermilab E906/SeaQuest experiment.
Strange Quark Contribution to the Nucleon Spin from Electroweak Elastic Scattering Data
S. F. Pate; J. P. Schaub; D. P. Trujillo
2012-08-29T23:59:59.000Z
The total contribution of strange quarks to the intrinsic spin of the nucleon can be determined from a measurement of the strange-quark contribution to the nucleon's elastic axial form factor. We have studied the strangeness contribution to the elastic vector and axial form factors of the nucleon, using elastic electroweak scattering data. Specifically, we combine elastic $\
Lower scaling dimensions of quarks and gluons and new energy scales
F. Palumbo
1996-05-08T23:59:59.000Z
We consider the possibility that quarks and gluons, due to confinement, have lower scaling dimensions. In such a case there appear naturally new energy scales below which the standard theory is recovered. Arguments are given whereby for dimension $1/2$ of the quarks the theory is unitary also above these energy scales.
Neutrino emissivity and bulk viscosity of iso-CSL quark matter in neutron stars
David B. Blaschke; Jens Berdermann
2007-10-27T23:59:59.000Z
We present results for neutrino emissivities and bulk viscosities of a two-flavor color superconducting quark matter phase with isotropic color-spin-locked (iso-CSL) single-flavor pairing which fulfill the constraints on quark matter derived from cooling and rotational evolution of compact stars. We compare with results for the phenomenologically successful, but yet heuristic 2SC+X phase.
Search for pair production of excited top quarks in the lepton + jets final state
Apyan, Aram
A search is performed for pair-produced spin-3/2 excited top quarks (t[superscript ?][¯ over t][superscript ?]), each decaying to a top quark and a gluon. The search uses data collected with the CMS detector from pp ...
Quark Contributions to Baryon Magnetic Moments in Full, Quenched and Partially Quenched QCD
Derek B. Leinweber
2004-06-02T23:59:59.000Z
The chiral nonanalytic behaviour of quark-flavor contributions to the magnetic moments of octet baryons are determined in full, quenched and partially-quenched QCD, using an intuitive and efficient diagrammatic formulation of quenched and partially-quenched chiral perturbation theory. The technique provides a separation of quark-sector magnetic-moment contributions into direct sea-quark loop, valence-quark, indirect sea-quark loop and quenched valence contributions, the latter being the conventional view of the quenched approximation. Both meson and baryon mass violations of SU(3)-flavor symmetry are accounted for. Following a comprehensive examination of the individual quark-sector contributions to octet baryon magnetic moments, numerous opportunities to observe and test the underlying structure of baryons and the nature of chiral nonanalytic behavior in QCD and its quenched variants are discussed. In particular, the valence u-quark contribution to the proton magnetic moment provides the optimal opportunity to directly view nonanalytic behavior associated with the meson cloud of full QCD and the quenched meson cloud of quenched QCD. The u quark in Sigma^+ provides the best opportunity to display the artifacts of the quenched approximation.
Controversy concerning the definition of quark and gluon angular momentum
Leader, Elliot [Blackett laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)
2011-05-01T23:59:59.000Z
A major controversy has arisen in QCD as to how to split the total angular momentum into separate quark and gluon contributions, and as to whether the gluon angular momentum can itself be split, in a gauge-invariant way, into a spin and orbital part. Several authors have proposed various answers to these questions and offered a variety of different expressions for the relevant operators. I argue that none of these is acceptable and suggest that the canonical expression for the momentum and angular momentum operators is the correct and physically meaningful one. It is then an inescapable fact that the gluon angular momentum operator cannot, in general, be split in a gauge-invariant way into a spin and orbital part. However, the projection of the gluon spin onto its direction of motion, i.e. its helicity is gauge invariant and is measured in deep inelastic scattering on nucleons. The Ji sum rule, relating the quark angular momentum to generalized parton distributions, though not based on the canonical operators, is shown to be correct, if interpreted with due care. I also draw attention to several interesting aspects of QED and QCD, which, to the best of my knowledge, are not commented upon in the standard textbooks on field theory.
Neutrality of a magnetized two-flavor quark superconductor
Tanumoy Mandal; Prashanth Jaikumar
2012-09-11T23:59:59.000Z
We investigate the effect of electric and color charge neutrality on the two-flavor color superconducting (2SC) phase of cold and dense quark matter in presence of constant external magnetic fields and at moderate baryon densities. Within the framework of the Nambu-Jona-Lasinio (NJL) model, we study the inter-dependent evolution of the quark's BCS gap and constituent mass with increasing density and magnetic field. While confirming previous results derived for the highly magnetized 2SC phase with color neutrality alone, we obtain new results as a consequence of imposing charge neutrality. In the charge neutral gapless 2SC phase (g2SC), a large magnetic field drives the color superconducting phase transition to a crossover, while the chiral phase transition is first order. Assuming that LOFF phases do not arise, we also obtain the Clogston-Chandrasekhar limit at a very large value of the magnetic field (B ~ 10^{19}G) in the g2SC phase. At larger diquark-to-scalar coupling ratio G_D/G_S, where the 2SC phase is preferred, this limit is strongly affected by Shubnikov de Haas-van Alphen oscillations of the gap, indicating the transition to a domain-like state.
QCD sum rule determination of the charm-quark mass
Bodenstein, S. [Centre for Theoretical and Mathematical Physics, University of Cape Town, Rondebosch 7700 (South Africa); Bordes, J.; Penarrocha, J. [Departamento de Fisica Teorica, Universitat de Valencia, and Instituto de Fisica Corpuscular, Centro Mixto Universitat de Valencia-CSIC (Spain); Dominguez, C. A. [Centre for Theoretical and Mathematical Physics, University of Cape Town, Rondebosch 7700 (South Africa); Department of Physics, Stellenbosch University, Stellenbosch 7600 (South Africa); Schilcher, K. [Institut fuer Physik, Johannes Gutenberg-Universitaet Staudingerweg 7, D-55099 Mainz (Germany)
2011-04-01T23:59:59.000Z
QCD sum rules involving mixed inverse moment integration kernels are used in order to determine the running charm-quark mass in the MS scheme. Both the high and the low energy expansion of the vector current correlator are involved in this determination. The optimal integration kernel turns out to be of the form p(s)=1-(s{sub 0}/s){sup 2}, where s{sub 0} is the onset of perturbative QCD. This kernel enhances the contribution of the well known narrow resonances, and reduces the impact of the data in the range s{approx_equal}20-25 GeV{sup 2}. This feature leads to a substantial reduction in the sensitivity of the results to changes in s{sub 0}, as well as to a much reduced impact of the experimental uncertainties in the higher resonance region. The value obtained for the charm-quark mass in the MS scheme at a scale of 3 GeV is m{sub c}(3 GeV)=987{+-}9 MeV, where the error includes all sources of uncertainties added in quadrature.
Evidence for single top quark production using Bayesian neural networks
Kau, Daekwang; /Florida State U.
2007-08-01T23:59:59.000Z
We present results of a search for single top quark production in p{bar p} collisions using a dataset of approximately 1 fb{sup -1} collected with the D0 detector. This analysis considers the muon+jets and electron+jets final states and makes use of Bayesian neural networks to separate the expected signals from backgrounds. The observed excess is associated with a p-value of 0.081%, assuming the background-only hypothesis, which corresponds to an excess over background of 3.2 standard deviations for a Gaussian density. The p-value computed using the SM signal cross section of 2.9 pb is 1.6%, corresponding to an expected significance of 2.2 standard deviations. Assuming the observed excess is due to single top production, we measure a single top quark production cross section of {sigma}(p{bar p} {yields} tb + X, tqb + X) = 4.4 {+-} 1.5 pb.
Leptogenesis within a generalized quark-lepton symmetry
Buccella, F.; Falcone, D.; Oliver, L. [Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Naples (Italy) and INFN, Sezione di Napoli (Italy); Dipartimento di Scienze Fisiche, Universita di Napoli, Via Cintia, Naples (Italy); Laboratoire de Physique Theorique, Universite de Paris XI, Batiment 210, Orsay Cedex (France)
2008-02-01T23:59:59.000Z
We reexamine the question of baryogenesis via leptogenesis in schemes of the seesaw mechanism with quark-lepton symmetry. Within the phenomenological approach of textures, we propose to relax this strict symmetry and propose weaker conditions, namely, models of the neutrino Dirac mass matrix M{sub D} which have the same hierarchy as the matrix elements of M{sub u}. We call this guideline generalized hierarchical quark-lepton symmetry. We consider in detail particular cases in which the moduli of the matrix elements of M{sub D} are equal to those of M{sub u}. We try for the heavy Majorana mass matrix diagonal and off-diagonal forms. We find that an ansatz for M{sub D} preserving the hierarchy, together with an off-diagonal model for the heavy Majorana neutrino mass, is consistent with neutrino masses, neutrino mixing, and baryogenesis via leptogenesis for an intermediate mass scale m{sub R}{approx}10{sup 12} GeV. The preservation of the hierarchical structure could come from a possible symmetry scheme.
Bootstrap Dynamical Symmetry Breaking with New Heavy Chiral Quarks
Yukihiro Mimura; Wei-Shu Hou; Hiroaki Kohyama
2013-01-31T23:59:59.000Z
A Higgs-like new boson with mass around 126 GeV is now established, but its true nature probably cannot be settled with 2011--2012 LHC data. We assume it is a dilaton with couplings weaker than the Higgs boson (except to $\\gamma\\gamma$ and $gg$), and explore dynamical symmetry breaking (DSB) by strong Yukawa coupling of a yet unseen heavy chiral quark doublet $Q$. Assuming the actual Higgs boson to be heavy, the Goldstone boson $G$ of electroweak symmetry breaking still couples to $Q$ with Yukawa coupling $\\lambda_Q$. A ``bootstrap" gap equation without a Higgs particle is constructed. Electroweak symmetry breaking via strong $\\lambda_Q$ generates both heavy mass for $Q$, while self-consistently justifying $G$ as a massless Goldstone particle in the loop. The spontaneous breaking of scale invariance in principle \\emph{allows} for a dilaton. We numerically solve such a gap equation and find the mass of the heavy quark to be a couple of TeV. We offer a short critique on the results of the scale-invariant model of Hung and Xiong, where a similar gap equation is built with a massless scalar doublet. Through this we show that a light SM Higgs at 126 GeV cannot be viable within our approach to DSB, while a dilaton with weaker couplings is consistent with our main result.