Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Jet Measurements And Reconstruction Biases In Proton Proton And Pb Pb Collisions With Alice At The Lhc PDF full book. Access full book title Jet Measurements And Reconstruction Biases In Proton Proton And Pb Pb Collisions With Alice At The Lhc.
| Author | : Bastian Bathen |
| Publisher | : |
| Total Pages | : 0 |
| Release | : 2012 |
| Genre | : |
| ISBN | : |
| Author | : Constantin Loizides |
| Publisher | : ibidem-Verlag / ibidem Press |
| Total Pages | : 180 |
| Release | : 2012-02-03 |
| Genre | : Science |
| ISBN | : 3838255577 |
The ALICE experiment is one of the experiments currently prepared for the Large Hadron Collider (LHC) at CERN, Geneva, starting operation end of 2007. ALICE is dedicated to the research on nucleus-nucleus collisions at ultra-relativistic energies, which addresses the properties of strongly interacting matter under varying conditions of high density and temperature. The conditions provided at the LHC allow significant qualitative improvement with respect to previous studies. In particular, energetic probes, light quarks and gluons, will be abundantly produced. These probes might be identified by their fragmentation into correlated particles, so called jets, of high enough energy to allow full reconstruction of jet properties; even in the underlying heavy-ion environment.Understanding the dependence of high-energy jet production and fragmentation influenced by the dense medium created in the collision region is an open field of active research. Generally, one expects energy loss of the probes due to medium-induced gluon radiation. It is suggested that hadronization products of these, rather soft gluons may be contained within the jet emission cone, resulting in a modification of the characteristic jet fragmentation, as observed via longitudinal and transverse momentum distributions with respect to the direction of the initial parton, as well as of the multiplicity distributions arising from the jet fragmentation. Particle momenta parallel to the jet axis are softened (jet quenching), while transverse to it increased (transverse heating). The present thesis studies the capabilities of the ALICE detectors to measure these jets and quantifies obtainable rates and the quality of jet reconstruction, in both proton-proton and lead-lead collisions at the LHC. In particular, it is addressed whether modification of the jet fragmentation can be detected within the high-particle-multiplicity environment of central lead-lead collisions.
| Author | : Simone Marzani |
| Publisher | : Springer |
| Total Pages | : 205 |
| Release | : 2019-05-11 |
| Genre | : Science |
| ISBN | : 3030157091 |
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.
| Author | : Joel Anthony Mazer |
| Publisher | : |
| Total Pages | : 224 |
| Release | : 2017 |
| Genre | : Hadron interactions |
| ISBN | : |
In relativistic heavy ion collisions at the Large Hadron Collider (LHC), a hot, dense and strongly interacting medium known as the Quark Gluon Plasma (QGP) is produced. Quarks and gluons from incoming nuclei collide to produce partons at high momenta early in the collisions. By fragmenting into collimated sprays of hadrons, these partons form 'jets'. Within the framework of perturbative Quantum Chromodynamics (pQCD), jet production is well understood in pp collisions. We can use jets measured in pp interactions as a baseline reference for comparing to heavy ion collision systems to detect and study jet quenching. The jet quenching mechanism can be studied through the angular correlations of trigger jets with charged hadrons and is examined in transverse momentum bins of the trigger jets, transverse momentum bins of the associated hadrons, and studied as a function of collision centrality. A highly robust and precise background subtraction method is used in this analysis to remove the complex, flow dominated, heavy ion background. The analysis of angular correlations for different orientations of the trigger jet relative to the event plane allows for the study of the path length dependence of medium modifications to jets. The event plane dependence of azimuthal angular correlations of charged hadrons with respect to the axis of an R=0.2 reconstructed 'trigger' full (charged + neutral) jet in Pb--Pb collisions at [square root s subscript NN] 2.76 TeV in ALICE will be discussed. Results will be compared for three angular bins of the trigger jet relative to the event plane in mid-peripheral events. The status of jet yields and widths relative to the event plane will be discussed. There is no significant event plane dependence within the current uncertainties. Path length dependence of energy loss is seen to be a secondary effect to statistical fluctuations and in-medium energy loss mechanisms.
| Author | : Patrick L.S. Connor |
| Publisher | : Springer Nature |
| Total Pages | : 325 |
| Release | : 2019-11-29 |
| Genre | : Science |
| ISBN | : 3030343839 |
^ 74 GeV and |y| 2.4; the b jets must contain a B hadron. The measurement has significant statistics up to p T ∼ O(TeV). Advanced methods of unfolding are performed to extract the signal. It is found that fixed-order calculations with underlying event describe the measurement well.
| Author | : Hermes León Vargas |
| Publisher | : |
| Total Pages | : |
| Release | : 2015 |
| Genre | : |
| ISBN | : |
| Author | : Andrea Festanti |
| Publisher | : Springer |
| Total Pages | : 184 |
| Release | : 2016-09-07 |
| Genre | : Science |
| ISBN | : 3319434551 |
This thesis presents the first measurement of charmed D0 meson production relative to the reaction plane in Pb–Pb collisions at the center-of-mass energy per nucleon-nucleon collision of √sNN = 2.76 TeV. It also showcases the measurement of the D0 production in p–Pb collisions at √sNN = 5.02 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement of the D0 azimuthal anisotropy with respect to the reaction plane indicates that low- momentum charm quarks participate in the collective expansion of the high-density, strongly interacting medium formed in ultra-relativistic heavy-ion collisions, despite their large mass. This behavior can be explained by charm hadronization via recombination with light quarks from the medium and collisional energy loss. The measurement of the D0 production in p–Pb collisions is crucial to separate the effect induced by cold nuclear matter from the final- state effects induced by the hot medium formed in Pb–Pb collisions. The D0 production in p–Pb collisions is consistent with the binary collision scaling of the production in pp collisions, demonstrating that the modification of the momentum distribution observed in Pb–Pb collisions with respect to pp is predominantly induced by final-state effects such as the charm energy loss.
| Author | : Fabrizio Grosa |
| Publisher | : Springer |
| Total Pages | : 215 |
| Release | : 2022-04-18 |
| Genre | : Science |
| ISBN | : 9783030711337 |
This thesis provides a comprehensive view of the physics of charmed hadrons in high-energy proton-proton and heavy-ion collisions. Given their large masses, charm quarks are produced in the early stage of a heavy-ion collision and they subsequently experience the full system evolution probing the colour-deconfined medium called quark-gluon plasma (QGP) created in such collisions. In this thesis, the mechanisms of charm-quark in-medium energy loss and hadronisation are discussed via the measurements of the production of charm mesons with (Ds+) and without (D+) strange-quark content in different colliding systems, using data collected by the ALICE experiment at the CERN LHC. The participation of the charm quark and its possible thermalisation in the QGP are studied via measurements of azimuthal anisotropies in the production of D+ mesons. Finally, the prospects for future measurements with the upgraded ALICE experimental apparatus and with more refined machine learning techniques are presented.
| Author | : Nele Boelaert |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 176 |
| Release | : 2011-10-26 |
| Genre | : Science |
| ISBN | : 3642245978 |
This thesis is based on the first data from the Large Hadron Collider (LHC) at CERN. Its theme can be described as the classical Rutherford scattering experiment adapted to the LHC: measurement of scattering angles to search for new physics and substructure. At the LHC, colliding quarks and gluons exit the proton collisions as collimated particle showers, or jets. The thesis presents studies of the scattering angles of these jets. It includes a phenomenological study at the LHC design energy of 14 TeV, where a model of so-called large extra dimensions is used as a benchmark process for the sensitivity to new physics. The experimental result is the first measurement, made in 2010, by ATLAS, operating at the LHC start-up energy of 7 TeV. The result is compatible with the Standard Model and demonstrates how well the physics and the apparatus are understood. The first data is a tiny fraction of what will be accumulated in the coming years, and this study has set the stage for performing these measurements with confidence as the LHC accumulates luminosity and increases its energy, thereby probing smaller length scales.
| Author | : Christopher Ghanim Yaldo |
| Publisher | : |
| Total Pages | : 162 |
| Release | : 2015 |
| Genre | : Cold fusion |
| ISBN | : |
In heavy-ion collisions at RHIC and the LHC, a suppression of the nuclear modification factor for jets along with other strongly interacting particles has been observed relative to proton-proton collisions. To unambiguously determine if this suppression is due to the creation of a strongly interacting medium of de-confied partons referred to as the Quark-Gluon Plasma, or due to Cold Nuclear Matter effects, a "control experiment" is required. Proton-lead collisions serve as this control experiment, because these colli- sions are expected to be sensitive to cold nuclear matter effects while not producing a QGP at this collision energy ({591}sNN = 5.02 TeV). Presented in this defense are the first measurements of charged + neutral jets in p-Pb collisions using the ALICE detector at the LHC. Measurements of CNM effects are done via the nuclear modification factor for jets: RpPb, RCP, and the jet structure ratio. Measurements of the jet spectrum along with a detailed and proper discussion of the statistical, systematic, and normalization uncertain- ties will be presented. Also a comparison of RpPb and RCP measured in this analysis to other measured RpPb and RCP from ATLAS and CMS will be presented. All the measurements performed in this analysis indicate that no strong cold nuclear matter effects are observed in p-Pb collisions using the ALICE detector at the LHC.
