Medium Modification of the Shape of Small-radius Jets in Central Pb-Pb Collisions at √sNN
Medium Modification of the Shape of Small-radius Jets in Central Pb-Pb Collisions at √sNN

Author: Shreyasi Acharya

Publisher:

Published: 2018

Total Pages: 0

ISBN-13:

DOWNLOAD EBOOK

We present the measurement of a new set of jet shape observables for track-based jets in central Pb-Pb collisions at sNN---√=2.76 TeV. The set of jet shapes includes the first radial moment or angularity, g; the momentum dispersion, pTD; and the difference between the leading and sub-leading constituent track transverse momentum, LeSub. These observables provide complementary information on the jet fragmentation and can constrain different aspects of the theoretical description of jet-medium interactions. The jet shapes were measured for a small resolution parameter R = 0.2 and were fully corrected to particle level. The observed jet shape modifications indicate that in-medium fragmentation is harder and more collimated than vacuum fragmentation as obtained by PYTHIA calculations, which were validated with the measurements of the jet shapes in proton-proton collisions at s√=7 TeV. The comparison of the measured distributions to templates for quark and gluon-initiated jets indicates that in-medium fragmentation resembles that of quark jets in vacuum. We further argue that the observed modifications are not consistent with a totally coherent energy loss picture where the jet loses energy as a single colour charge, suggesting that the medium resolves the jet structure at the angular scales probed by our measurements (R = 0.2). Furthermore, we observe that small-R jets can help to isolate purely energy loss effects from other effects that contribute to the modifications of the jet shower in medium such as the correlated background or medium response.

Looking Inside Jets
Looking Inside Jets

Author: Simone Marzani

Publisher: Springer

Published: 2019-05-11

Total Pages: 210

ISBN-13: 3030157091

DOWNLOAD EBOOK

This concise primer reviews the latest developments in the field of jets. Jets are collinear sprays of hadrons produced in very high-energy collisions, e.g. at the LHC or at a future hadron collider. They are essential to and ubiquitous in experimental analyses, making their study crucial. At present LHC energies and beyond, massive particles around the electroweak scale are frequently produced with transverse momenta that are much larger than their mass, i.e., boosted. The decay products of such boosted massive objects tend to occupy only a relatively small and confined area of the detector and are observed as a single jet. Jets hence arise from many different sources and it is important to be able to distinguish the rare events with boosted resonances from the large backgrounds originating from Quantum Chromodynamics (QCD). This requires familiarity with the internal properties of jets, such as their different radiation patterns, a field broadly known as jet substructure. This set of notes begins by providing a phenomenological motivation, explaining why the study of jets and their substructure is of particular importance for the current and future program of the LHC, followed by a brief but insightful introduction to QCD and to hadron-collider phenomenology. The next section introduces jets as complex objects constructed from a sequential recombination algorithm. In this context some experimental aspects are also reviewed. Since jet substructure calculations are multi-scale problems that call for all-order treatments (resummations), the bases of such calculations are discussed for simple jet quantities. With these QCD and jet physics ingredients in hand, readers can then dig into jet substructure itself. Accordingly, these notes first highlight the main concepts behind substructure techniques and introduce a list of the main jet substructure tools that have been used over the past decade. Analytic calculations are then provided for several families of tools, the goal being to identify their key characteristics. In closing, the book provides an overview of LHC searches and measurements where jet substructure techniques are used, reviews the main take-home messages, and outlines future perspectives.

Introduction to Relativistic Heavy Ion Physics
Introduction to Relativistic Heavy Ion Physics

Author: Jerzy Bartke

Publisher: World Scientific

Published: 2009

Total Pages: 239

ISBN-13: 9810212313

DOWNLOAD EBOOK

This book attempts to cover the fascinating field of physics of relativistic heavy ions, mainly from the experimentalist's point of view. After the introductory chapter on quantum chromodynamics, basic properties of atomic nuclei, sources of relativistic nuclei, and typical detector set-ups are described in three subsequent chapters. Experimental facts on collisions of relativistic heavy ions are systematically presented in 15 consecutive chapters, starting from the simplest features like cross sections, multiplicities, and spectra of secondary particles and going to more involved characteristics like correlations, various relatively rare processes, and newly discovered features: collective flow, high pT suppression and jet quenching. Some entirely new topics are included, such as the difference between neutron and proton radii in nuclei, heavy hypernuclei, and electromagnetic effects on secondary particle spectra.Phenomenological approaches and related simple models are discussed in parallel with the presentation of experimental data. Near the end of the book, recent ideas about the new state of matter created in collisions of ultrarelativistic nuclei are discussed. In the final chapter, some predictions are given for nuclear collisions in the Large Hadron Collider (LHC), now in construction at the site of the European Organization for Nuclear Research (CERN), Geneva. Finally, the appendix gives us basic notions of relativistic kinematics, and lists the main international conferences related to this field. A concise reference book on physics of relativistic heavy ions, it shows the present status of this field.

Heavy Flavours
Heavy Flavours

Author: A J Buras

Publisher: World Scientific

Published: 1992-11-26

Total Pages: 803

ISBN-13: 9814602825

DOWNLOAD EBOOK

This volume is a collection of review articles on the most outstanding topics in heavy flavour physics. All the authors have made significant contributions to this field. The book reviews in detail the theoretical structure of heavy flavour physics within the Standard Model and its confrontation with existing experimental data.The physics of the top quark and of the Higgs play an important role in this volume. Beginning with radiative electroweak corrections and their impressive tests at LEP and hadron colliders, the book summarizes the present status of quark mixing, CP violation and rare decays. The dynamics of exclusive D- and B-meson decays, the τ-lepton physics and the newly discovered heavy quark symmetries are discussed in detail. The impact of strong interactions on weak decays is clearly visible in many articles. The physics of heavy flavours at LEP, HERA and hadron colliders constitutes an important part of the book. Another significant topic is the possible role of heavy flavours in the spontaneous symmetry breaking of gauge symmetries. Finally the most recent advances in lattice calculations of the properties of heavy flavours and the lattice studies of the dynamics of heavy flavours are presented.

Quark--Gluon Plasma 3
Quark--Gluon Plasma 3

Author: Rudolph C. Hwa

Publisher: World Scientific

Published: 2004

Total Pages: 786

ISBN-13: 9812795537

DOWNLOAD EBOOK

Annotation. Text reviews the major topics in Quark-Gluon Plasma, including: the QCD phase diagram, the transition temperature, equation of state, heavy quark free energies, and thermal modifications of hadron properties. Includes index, references, and appendix. For researchers and practitioners.

Relativistic Heavy Ion Physics
Relativistic Heavy Ion Physics

Author: Reinhard Stock

Publisher: Springer Science & Business Media

Published: 2010-04-01

Total Pages: 701

ISBN-13: 3642015387

DOWNLOAD EBOOK

This new volume, I/23, of the Landolt-Börnstein Data Collection series continues a tradition inaugurated by the late Editor-in-Chief, Professor Werner Martienssen, to provide in the style of an encyclopedia a summary of the results and ideas of Relativistic Heavy Ion Physics. Formerly, the Landolt-Börnstein series was mostly known as a compilation of numerical data and functional relations, but it was felt that the more comprehensive summary undertaken here should meet an urgent purpose. Volume I/23 reports on the present state of theoretical and experimental knowledge in the field of Relativistic Heavy Ion Physics. What is meant by this rather technical terminology is the study of strongly interacting matter, and its phases (in short QCD matter) by means of nucleus-nucleus collisions at relativistic energy. The past decade has seen a dramatic progress, and widening of scope in this field, which addresses one of the chief remaining open frontiers of Quantum Chromodynamics (QCD) and, in a wider sense, the "Standard Model of Elementary Interactions". The data resulting from the CERN SPS, BNL AGS and GSI SIS experiments, and in particular also from almost a decade of experiments carried out at the "Relativistic Heavy Ion Collider"(RHIC) at Brookhaven, have been fully analyzed, uncovering a wealth of information about both the confined and deconfined phases of QCD at high energy density.

Kolmogorov Spectra of Turbulence I
Kolmogorov Spectra of Turbulence I

Author: Vladimir E. Zakharov

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 275

ISBN-13: 3642500528

DOWNLOAD EBOOK

Since the human organism is itself an open system, we are naturally curious about the behavior of other open systems with fluxes of matter, energy or information. Of the possible open systems, it is those endowed with many degrees of freedom and strongly deviating from equilibrium that are most challenging. A simple but very significant example of such a system is given by developed turbulence in a continuous medium, where we can discern astonishing features of universality. This two-volume monograph deals with the theory of turbulence viewed as a general physical phenomenon. In addition to vortex hydrodynamic turbulence, it considers various cases of wave turbulence in plasmas, magnets, atmosphere, ocean and space. A sound basis for discussion is provided by the concept of cascade turbulence with relay energy transfer over different scales and modes. We shall show how the initial cascade hypothesis turns into an elegant theory yielding the Kolmogorov spectra of turbulence as exact solutions. We shall describe the further development of the theory discussing stability prob lems and modes of Kolmogorov spectra formation, as well as their matching with sources and sinks. This volume is dedicated to developed wave turbulence in different media.

Relativistic Heavy-ion Collisions
Relativistic Heavy-ion Collisions

Author: Rudolph C. Hwa

Publisher: CRC Press

Published: 1990

Total Pages: 338

ISBN-13: 9782881247347

DOWNLOAD EBOOK

Papers of the June 1989 meeting in Beijing by the China Center of Advanced Science and Technology. This small book covers nucleus- nucleus collisions, states of the vacuum, and highly relativistic heavy ions in the experimental realm. Theoretical papers deal with quark-gluon plasma, and relativistic heavy ion collisions. Annotation copyrighted by Book News, Inc., Portland, OR