HERA Collider Physics - Introduction
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Followed by a Stretcher That Fits Into the Same
as the booster; the main synchro what cheaper because some ex tunnel (this would require comple tron taking the beam to the final penditure on buildings and general mentary funding beyond the normal energy; followed by a stretcher infrastructure would be saved. CERN budget); and at the Swiss that fits into the same tunnel as In his concluding remarks, SIN Laboratory. Finally he pointed the main ring of circumference 960 F. Scheck of Mainz, chairman of out that it was really one large m (any resemblance to existing the EHF Study Group, pointed out community of future users, not presently empty tunnels is not that the physics case for EHF was three, who were pushing for a unintentional). Bradamante pointed well demonstrated, that there was 'kaon factory'. Whoever would be out that earlier criticisms are no a strong and competent European first to obtain approval, the others longer valid. The price seems un physics community pushing for it, would beat a path to his door. der control, the total investment and that there were good reasons National decisions on the project for a 'green pasture' version for building it in Europe. He also will be taken this year. amounting to about 870 million described three site options: a Deutschmarks. A version using 'green pasture' version in Italy; at By Florian Scheck existing facilities would be some- CERN using the now defunct ISR A ZEUS group meeting, with spokesman Gunter Wolf one step in front of the pack. (Photo DESY) The HERA electron-proton collider now being built at the German DESY Laboratory in Hamburg will be a unique physics tool. -
Accelerator Search of the Magnetic Monopo
Accelerator Based Magnetic Monopole Search Experiments (Overview) Vasily Dzhordzhadze, Praveen Chaudhari∗, Peter Cameron, Nicholas D’Imperio, Veljko Radeka, Pavel Rehak, Margareta Rehak, Sergio Rescia, Yannis Semertzidis, John Sondericker, and Peter Thieberger. Brookhaven National Laboratory ABSTRACT We present an overview of accelerator-based searches for magnetic monopoles and we show why such searches are important for modern particle physics. Possible properties of monopoles are reviewed as well as experimental methods used in the search for them at accelerators. Two types of experimental methods, direct and indirect are discussed. Finally, we describe proposed magnetic monopole search experiments at RHIC and LHC. Content 1. Magnetic Monopole characteristics 2. Experimental techniques 3. Monopole Search experiments 4. Magnetic Monopoles in virtual processes 5. Future experiments 6. Summary 1. Magnetic Monopole characteristics The magnetic monopole puzzle remains one of the fundamental and unsolved problems in physics. This problem has a along history. The military engineer Pierre de Maricourt [1] in1269 was breaking magnets, trying to separate their poles. P. Curie assumed the existence of single magnetic poles [2]. A real breakthrough happened after P. Dirac’s approach to the solution of the electron charge quantization problem [3]. Before Dirac, J. Maxwell postulated his fundamental laws of electrodynamics [4], which represent a complete description of all known classical electromagnetic phenomena. Together with the Lorenz force law and the Newton equations of motion, they describe all the classical dynamics of interacting charged particles and electromagnetic fields. In analogy to electrostatics one can add a magnetic charge, by introducing a magnetic charge density, thus magnetic fields are no longer due solely to the motion of an electric charge and in Maxwell equation a magnetic current will appear in analogy to the electric current. -
The Design and Performance of the ZEUS Micro Vertex Detector
The design and performance of the ZEUS Micro Vertex Detector A. Polini University and INFN Bologna, Bologna, Italy1 I. Brock, S. Goers, A. Kappes, U. F. Katz, E. Hilger, J. Rautenberg, A. Weber Physikalisch.es Institut der Universitdt Bonn, Bonn, Germany2 2007 A. Mastroberardino, E. Tassi Caia&ria Dnireraitp, PApsica Department and DVPW, Coaenza, dtatp ^ Aug V. Adler, L. A. T. Bauerdick, L Bloch, T. Haas *, U. Klein, U. Koetz, G. Kramberger, 21 E. Lobodzinska, R. Mankel, J. Ng, D. Notz, M. C. Petrucci, B. Sarrow, G. Watt, C. Youngman, W. Zeuner Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany C. Coldewey, R. Heller Deutsches Elektronen-Synchrotron DESY, Zeuthen, Germany E. Gallo University and. INFN, Florence, Italy1 T. Carli, V. Chiochia, D. Dannheim, E. Fretwurst, A. Garfagnini, R. Klanner, B. Koppitz, J. Martens, M. Milite [physics.ins-det] Hamburg University, Institute of Exp. Physics, Hamburg, Germ.a.ny 3 Katsuo Tokushuku Institute of Particle and Nuclear Studies, KEK, Tsukuba, Japan.4 I. Redondo Dnireraidad Antonoma de Madrid, Madrid, .Spain ^ H. Boterenbrood, E. KofTeman, P. Kooijman, E. Maddox, H. Tiecke, M. Vazquez, J. Velthuis, L. Wiggers, NIKHEF and University of Amsterdam., Amsterdam, Netherlands 6 R.C.E. Devenish, M. Dawson, J. Ferrando, G. Grzelak, K. Korcsak-Gorzo, T. Matsushita, K. Oliver, P. Shield, R. Walczak arXiv:0708.3011vl Department o/ f Apaics, Dnireraitp o/ Oa^ord, Oa^ord, United kingdom ' DESYOT-131 A. Bertolin, E. Borsato, R. Carlin, F. Dal Corso, A. Longhin, M. Turcato Dipartimento di Fisica dell' University and INFN, Padova, Italy*1 T. Fusayasu, R. Hori, T. Kohno, S. Shimizu Department of Physics, University of Tokyo, Tokyo, Japan 4 H. -
An Analysis on Single and Central Diffractive Heavy Flavour Production at Hadron Colliders
416 Brazilian Journal of Physics, vol. 38, no. 3B, September, 2008 An Analysis on Single and Central Diffractive Heavy Flavour Production at Hadron Colliders M. V. T. Machado Universidade Federal do Pampa, Centro de Cienciasˆ Exatas e Tecnologicas´ Campus de Bage,´ Rua Carlos Barbosa, CEP 96400-970, Bage,´ RS, Brazil (Received on 20 March, 2008) In this contribution results from a phenomenological analysis for the diffractive hadroproduction of heavy flavors at high energies are reported. Diffractive production of charm, bottom and top are calculated using the Regge factorization, taking into account recent experimental determination of the diffractive parton density functions in Pomeron by the H1 Collaboration at DESY-HERA. In addition, multiple-Pomeron corrections are considered through the rapidity gap survival probability factor. We give numerical predictions for single diffrac- tive as well as double Pomeron exchange (DPE) cross sections, which agree with the available data for diffractive production of charm and beauty. We make estimates which could be compared to future measurements at the LHC. Keywords: Heavy flavour production; Pomeron physics; Single diffraction; Quantum Chromodynamics 1. INTRODUCTION the diffractive quarkonium production, which is now sensitive to the gluon content of the Pomeron at small-x and may be For a long time, diffractive processes in hadron collisions particularly useful in studying the different mechanisms for have been described by Regge theory in terms of the exchange quarkonium production. of a Pomeron with vacuum quantum numbers [1]. However, the nature of the Pomeron and its reaction mechanisms are In order to do so, we will use the hard diffractive factoriza- not completely known. -
A New Avenue to Parton Distribution Functions Uncertainties: Self-Organizing Maps Abstract
A New Avenue to Parton Distribution Functions Uncertainties: Self-Organizing Maps Abstract Neural network algorithms have been recently applied to construct Parton Distribution Functions (PDFs) parametrizations as an alternative to standard global fitting procedures. We propose a different technique, namely an interactive neural network algorithm using Self-Organizing Maps (SOMs). SOMs enable the user to directly control the data selection procedure at various stages of the process. We use all available data on deep inelastic scattering experiments in the kinematical region of 0:001 ≤ x ≤ 0:75, and 1 ≤ Q2 ≤ 100 GeV2, with a cut on the final state invariant mass, W 2 ≥ 10 GeV2. Our main goal is to provide a fitting procedure that, at variance with standard neural network approaches, allows for an increased control of the systematic bias. Controlling the theoretical uncertainties is crucial for determining the outcome of a variety of high energy physics experiments using hadron beams. In particular, it is a prerequisite for unambigously extracting from experimental data the signal of the Higgs boson, that is considered to be, at present, the key for determining the theory of the masses of all known elementary particles, or the Holy Grail of particle physics. PACS numbers: 13.60.-r, 12.38.-t, 24.85.+p 1 I. DEFINITION OF THE PROBLEM AND GENERAL REMARKS In high energy physics experiments one detects the cross section, σX , for observing a particle X during a given collision process. σX is proportional to the number of counts in the detector. It is, therefore, directly \observable". Consider the collision between two hadrons (a hadron is a more general name to indicate a proton, neutron...or a more exotic particle made of quarks). -
Collider Physics at HERA
ANL-HEP-PR-08-23 Collider Physics at HERA M. Klein1, R. Yoshida2 1University of Liverpool, Physics Department, L69 7ZE, Liverpool, United Kingdom 2Argonne National Laboratory, HEP Division, 9700 South Cass Avenue, Argonne, Illinois, 60439, USA May 21, 2008 Abstract From 1992 to 2007, HERA, the first electron-proton collider, operated at cms energies of about 320 GeV and allowed the investigation of deep-inelastic and photoproduction processes at the highest energy scales accessed thus far. This review is an introduction to, and a summary of, the main results obtained at HERA during its operation. To be published in Progress in Particle and Nuclear Physics arXiv:0805.3334v1 [hep-ex] 21 May 2008 1 Contents 1 Introduction 4 2 Accelerator and Detectors 5 2.1 Introduction.................................... ...... 5 2.2 Accelerator ..................................... ..... 6 2.3 Deep Inelastic Scattering Kinematics . ............. 9 2.4 Detectors ....................................... .... 12 3 Proton Structure Functions 15 3.1 Introduction.................................... ...... 15 3.2 Structure Functions and Parton Distributions . ............... 16 3.3 Measurement Techniques . ........ 18 3.4 Low Q2 and x Results .................................... 19 2 3.4.1 The Discovery of the Rise of F2(x, Q )....................... 19 3.4.2 Remarks on Low x Physics.............................. 20 3.4.3 The Longitudinal Structure Function . .......... 22 3.5 High Q2 Results ....................................... 23 4 QCD Fits 25 4.1 Introduction.................................... ...... 25 4.2 Determinations ofParton Distributions . .............. 26 4.2.1 TheZEUSApproach ............................... .. 27 4.2.2 TheH1Approach................................. .. 28 4.3 Measurements of αs inInclusiveDIS ............................ 29 5 Jet Measurements 32 5.1 TheoreticalConsiderations . ........... 32 5.2 Jet Cross-Section Measurements . ........... 34 5.3 Tests of pQCD and Determination of αs ......................... -
Neutral Strangeness Production with the ZEUS Detector at HERA
Neutral Strangeness Production with the ZEUS Detector at HERA Chuanlei Liu Department of Physics McGill University, Montreal, QC Canada January 2007 A thesis submitted to McGill University in partial fulfillment of the requirements of the degree of Doctor of Philosophy Chuanlei Liu, 2007 Abstract ¯ 0 The inclusive production of the neutral strange particles, Λ, Λ and KS, has been studied with the ZEUS detector at HERA. The measurement provides a way to understand the fragmentation process in ep collisions and to check the universality of this process. The strangeness cross sections have been measured and compared with Monte Carlo (MC) predictions. Over the kinematic regions of interest, no Λ ¯ 0 to Λ asymmetry was observed. The relative yield of Λ and KS was determined and the result was compared with MC calculations and results from other experiments. A good agreement was found except for the enhancement in the photoproduction process. Clear rapidity correlation was observed for particle pairs where either quark 0 0 flavor or baryon number compensation occurs. The KSKS Bose-Einstein correlation measurement gives a result consistent with those from LEP measurements. The Λ polarizations were measured to be consistent with zero for HERA I data. i ii Abstract Abstract in French ¯ 0 La mesure de production inclusive des particules ´etranges neutres Λ, Λ et KS avec le d´etecteur ZEUS a` HERA permet de comprendre le processus de fragmentation dans les collisions ep et de v´erifier son universalit´e. Les sections efficaces de produc- tion d'´etranget´e ont ´et´e mesur´ees et compar´ees avec les pr´edictions de simulations Monte-Carlo (MC). -
Experience of EW and BSM Physics at HERA and Lessons for EIC
Experience of EW and BSM physics at HERA and lessons for EIC Elisabetta Gallo (DESY and UHH) (A personal recollection and selection of topics) Electroweak and BSM physics at the EIC, 6/5/2020 Elisabetta Gallo (DESY) 1 HERA (1992-2007) First F2 presented by H1 at Diffractive events Durham 1993 discovered by ZEUS, DESY seminar 1993 • HERA experiments were built for high Q2 physics, F from H1 but adapted very well to lower Q2 low x L • With HERA II a stronger electroweak program coulD be starteD anD searches boosteD • At the enD of HERA II we went back to low-x physics with FL Elisabetta Gallo (DESY) 2 Increasing the luminosity (i.e. HERA II) • Access to higher Q2 • Access to valence quark distribution at higher x in NC, xF3 • Electron vs positron running (endless discussions) • More precise measurements of charged current • Polarized beams • Combination H1-ZEUS data (it started for xF3) • LHC was getting closer -> PDFs for LHC, more exchange, HERAPDFs • More exotic searches • Isolated leptons plus missing energy and large hadronic p Triggered by observation in T H1, no specific- related search • Multilepton events • Leptoquarks • FCNC • Contact interactions Elisabetta Gallo (DESY) 3 NC/CC at high Q2 Elisabetta Gallo (DESY) 4 Few words about ZEUS and H1 combinations • Unless specified the plots I am going to show are based on the latest combined data • And compared to HERAPDF2.0: based on data taken 1994-2007, 2927 points combined to 1307, 21 HERA I data samples, 20 HERA II data samples NC+CC EPJ C75 (2015) 580 • xFitter, open-source tool originally started • NC: 0.045< Q2< 50000 to fit PDFs at HERA GeV2 -7 ZEUS and H1 combination • Now used also for LHC 6 X 10 < x < 0.65 • CC: 200< Q2< 50000 is the main dataset for experiments (EIC?) PDFs fitters GeV2 1.3 X 10-2 < x < 0.40 Elisabetta Gallo (DESY) 5 Polarization at HERA II • EleCtrons/positrons get naturally transverse polarized (Solokov-Ternov effeCt) • Spin rotators to Change in long. -
Deep Inelastic Scattering
Particle Physics Michaelmas Term 2011 Prof Mark Thomson e– p Handout 6 : Deep Inelastic Scattering Prof. M.A. Thomson Michaelmas 2011 176 e– p Elastic Scattering at Very High q2 ,At high q2 the Rosenbluth expression for elastic scattering becomes •From e– p elastic scattering, the proton magnetic form factor is at high q2 Phys. Rev. Lett. 23 (1969) 935 •Due to the finite proton size, elastic scattering M.Breidenbach et al., at high q2 is unlikely and inelastic reactions where the proton breaks up dominate. e– e– q p X Prof. M.A. Thomson Michaelmas 2011 177 Kinematics of Inelastic Scattering e– •For inelastic scattering the mass of the final state hadronic system is no longer the proton mass, M e– •The final state hadronic system must q contain at least one baryon which implies the final state invariant mass MX > M p X For inelastic scattering introduce four new kinematic variables: ,Define: Bjorken x (Lorentz Invariant) where •Here Note: in many text books W is often used in place of MX Proton intact hence inelastic elastic Prof. M.A. Thomson Michaelmas 2011 178 ,Define: e– (Lorentz Invariant) e– •In the Lab. Frame: q p X So y is the fractional energy loss of the incoming particle •In the C.o.M. Frame (neglecting the electron and proton masses): for ,Finally Define: (Lorentz Invariant) •In the Lab. Frame: is the energy lost by the incoming particle Prof. M.A. Thomson Michaelmas 2011 179 Relationships between Kinematic Variables •Can rewrite the new kinematic variables in terms of the squared centre-of-mass energy, s, for the electron-proton collision e– p Neglect mass of electron •For a fixed centre-of-mass energy, it can then be shown that the four kinematic variables are not independent. -
Top Quark Physics in the Large Hadron Collider Era
Top Quark Physics in the Large Hadron Collider era Michael Russell Particle Physics Theory Group, School of Physics & Astronomy, University of Glasgow September 2017 arXiv:1709.10508v2 [hep-ph] 31 Jan 2018 A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy Abstract We explore various aspects of top quark phenomenology at the Large Hadron Collider and proposed future machines. After summarising the role of the top quark in the Standard Model (and some of its well-known extensions), we discuss the formulation of the Standard Model as a low energy effective theory. We isolate the sector of this effective theory that pertains to the top quark and that can be probed with top observables at hadron colliders, and present a global fit of this sector to currently available data from the LHC and Tevatron. Various directions for future improvement are sketched, including analysing the potential of boosted observables and future colliders, and we highlight the importance of using complementary information from different colliders. Interpretational issues related to the validity of the effective field theory formulation are elucidated throughout. Finally, we present an application of artificial neural network algorithms to identifying highly- boosted top quark events at the LHC, and comment on further refinements of our analysis that can be made. 2 Acknowledgements First and foremost I must thank my supervisors, Chris White and Christoph Englert, for their endless support, inspiration and encouragement throughout my PhD. They always gave me enough freedom to mature as a researcher, whilst providing the occasional neces- sary nudge to keep me on the right track. -
Three-Jet Production in Neutral Current Deep Inelastic Scattering with ZEUS Detector at HERA
Three-jet Production in Neutral Current Deep Inelastic Scattering with ZEUS Detector at HERA Preliminary Examination Liang Li University of Wisconsin Nov 27,2001 HERA • 820/920 GeV proton • 27.5 GeV electrons or positrons • 300/318 GeV center of mass energy • 220 bunches 96 ns crossing time • Instantaneous luminosity 1.8 x 1031 cm-2s-1 • Currents: ~90mA protons ~40mA positrons HERA Luminosity . 820 GeV protons through 1997 920 GeV since 1998 . ZEUS integrated luminosity since 1992: ~185 pb-1 . Expect 1fb-1 by end of 2005 HERA Kinematic Range Extended kinematic region not accessible by fixed target experiments, with some overlap. H1 and ZEUS: DESY e-p HERMES: DESY e-A E665: Fermilab µ-A BCDMS: CERN µ-A CCFR: Fermilab ν-A SLAC: many experiments e-A NMC: CERN µ-A Deep Inelastic Scattering W2 = (p+q)2 W=invariant mass of the final hadronic system e+pDIS Event at HERA DIS Cross Section 2 F2 (x,Q ): Interaction between transversely polarized photons & spin 1/2 partons ; Charge weighted sum of the quark distributions 2 FL (x,Q ): Interaction between longitudinally polarized photons & the partons with transverse momentum. 2 0 F3 (x,Q ): Parity-violating structure function from Z exchange. Naïve Quark Parton Model · Partons are point-like objects · No interaction between the partons · Structure function independent of Q2 Bjorken Scaling (x) dependence: − F (x,Q2) =∑ e 2(Q2) ·(xq(x,Q2) +xq(x,Q2)) 2 quarks q 2 → F2(x,Q ) F2(x), FL= 0 QCD Physics picture: presence of gluons Parton Parton interactions, mediated by gluons Generate parton transverse momentum Non zero FL The structure functions gain a Q2 dependence Scaling Violation Scaling Violation Parton Distribution Functions Derived from the experiment DGLAP Evolution Dokshitzer-Gribov-Lipatov-Altarelli-Parisi equations describe evolution of parton densities to higher Q2 — QCD prediction α s is the strong coupling constant. -
ZEUS EXPERIMENT at HERA ' ZEUS Collaboration 2 Group from the Institute of Nuclear Physics Includes: P
PL9700208 28 Section V ,.,.-; ZEUS EXPERIMENT AT HERA ' ZEUS Collaboration 2 Group from the Institute of Nuclear Physics includes: P. Borzeniski, J. Chwastowski, A. Eskreys, K. Piotrzkowski, M. Przybycieri, M. Zachara, L. Zawiejski (physicists) and J. Andruszkow, B. Dajarowski, W. Daniluk, P. Jurkiewicz, A. Kotarba, K. Oliwa. W. Wierba (engineers and technicians) Third year of HERA operation was a very successful one for the HERA crew. Experiments (ZEUS and HI) collected more than 3pb~1 of the integrated luminosity compared to ()00nb~^ in the previous year. Higher luminosity means also higher rates and higher background. That created new problems for our experiment at the beginning of the running period. The common effort of all groups taking care of the different detector components resulted in a smooth and successful running of the ZEUS experiment. The main responsibility of the Cracow group is the reliable performance of the Luminosity Monitor, which has been designed and built by our group. That means the maintenance of the detector, continuous development of the online and offline software tools and the luminosity measurement itself. A very detailed offline analysis of the 1993 luminosity data was done in 1994. This resulted in much better understanding of the systematic effects influencing the luminosity measurement. The systematic error in the determination of the integrated luminosity is now below 2.5%. Modification of the hardware setup, especially replacement of the photomultipliers in the calorimeters, made during the 1993/1994 winter shutdown, allowed for more stable opera- tion in the 1994 running period. Much improvement has also been achieved in both offline and online software.