Multiparticle Azimuthal Correlations in P -Pb and Pb-Pb Collisions at the CERN Large Hadron Collider PDF Download

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Languages : en
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Our measurements of multiparticle azimuthal correlations (cumulants) for charged particles in p-Pb at √sNN=5.02 TeV and Pb-Pb at √sNN=2.76 TeV collisions are presented. They help address the question of whether there is evidence for global, flowlike, azimuthal correlations in the p-Pb system. These comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a.

Author: Li Yi
Publisher: Springer
ISBN: 1493964879
Category : Science
Languages : en
Pages : 97

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This thesis covers several important topics relevant to our understanding of quark-gluon plasma. It describes measurement of the third-order harmonic flow using two-particle correlations and isolation of flow and non-flow contributions to particle correlations in gold-gold collisions. The work also investigates long-range longitudinal correlations in small systems of deuteron-gold collisions. The former is related to the hydrodynamic transport properties of the quark-gluon plasma created in gold-gold collisions. The latter pertains to the question whether hydrodynamics is applicable to small systems, such as deuteron-gold collisions, and whether the quark-gluon plasma can be formed in those small-system collisions. The work presented in this thesis was conducted with the STAR experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, where the center-of-mass energy of both collision systems was a factor of 100 larger than the rest mass of the colliding nuclei. The results contained in this thesis are highly relevant to our quest for deeper understanding of quantum chromodynamics. The results obtained challenge the interpretation of previous works from several other experiments on small systems, and provoke a fresh look at the physics of hydrodynamics and particle correlations pertinent to high energy nuclear collisions.

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Category :
Languages : en
Pages : 17

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The second-order azimuthal anisotropy Fourier harmonics, v2, are obtained in p-Pb and PbPb collisions over a wide pseudorapidity ([eta]) range based on correlations among six or more charged particles. The p-Pb data, corresponding to an integrated luminosity of 35 nb-1, were collected during the 2013 LHC p-Pb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. A sample of semiperipheral PbPb collision data at √sNN=2.76 TeV, corresponding to an integrated luminosity of 2.5 [mu]b-1 and covering a similar range of particle multiplicities as the p-Pb data, is also analyzed for comparison. The six- and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v2 coefficients, extending previous studies of two- and four-particle correlations. For both the p-Pb and PbPb systems, the v2 values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large [Delta][eta]) correlations in both systems. The ratios of v2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a p-Pb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multiparticle dynamics of collision systems with a very small overlapping region.

Author: Shengquan Tuo
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 97

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Author: Paolo Bartalini
Publisher: World Scientific Publishing
ISBN: 981322777X
Category : Science
Languages : en
Pages : 471

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Many high-energy collider experiments (including the current Large Hadron Collider at CERN) involve the collision of hadrons. Hadrons are composite particles consisting of partons (quarks and gluons), and this means that in any hadron-hadron collision there will typically be multiple collisions of the constituents — i.e. multiple parton interactions (MPI). Understanding the nature of the MPI is important in terms of searching for new physics in the products of the scatters, and also in its own right to gain a greater understanding of hadron structure. This book aims at providing a pedagogical introduction and a comprehensive review of different research lines linked by an involvement of MPI phenomena. It is written by pioneers as well as young leading scientists, and reviews both experimental findings and theoretical developments, discussing also the remaining open issues.

Author: Fabrizio Grosa
Publisher: Springer Nature
ISBN: 3030711315
Category : Science
Languages : en
Pages : 227

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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: Wang Wei
Publisher: World Scientific
ISBN: 9811207410
Category : Science
Languages : en
Pages : 576

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The latest of the 'Lepton Photon' symposium, one of the well-established series of meetings in the high-energy physics community, was successfully organized at the South Campus of Sun Yat-sen University, Guangzhou, China, from August 7-12, 2017, where physicists around the world gathered to discuss the latest advancements in the research field.This proceedings volume of the Lepton Photon 2017 collects contributions by the plenary session speakers and the posters' presenters, which cover the latest results in particle physics, nuclear physics, astrophysics, cosmology, and plans for future facilities.

Author: Andrea Festanti
Publisher: Springer
ISBN: 3319434551
Category : Science
Languages : en
Pages : 184

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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: Jocelyn Mlynarz
Publisher:
ISBN:
Category : Condensed matter
Languages : en
Pages : 150

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Quantum Chromodynamics, which describe the interactions of quarks and gluons, have been found not to violate global parity symmetry. However, the possibility of local parity violations due to transitions in the vacuum state of QCD is not excluded. The effects of these parity violations could be measured in the hot and dense medium created in the ultrarelativistic heavy ion collisions experiment conducted at the Large Hadron Collider, called a Quark-Gluon Plasma, in which the quarks that compose most of ordinary matter are deconfined. In the strong magnetic fields which permeate the QGP in non-central collisions, parity violation would express itself as a charge asymetry with respect to the reaction plane, a phenomenon called the Chiral Magnetic Effect. The measurements of the charge-dependent correlations in a heavy-ion collisions allows to experimentally probe effects of the CME. These measurements are conducted via the use of the second harmonic two-particle correlator with respect to the reaction plane, $\langle\cos(\phi_{a}+\phi_{b}-2\psi)\rangle$ The background affecting these measurements is the consequence of an interplay of strong anisotropic flow and correlations unrelated to the CME. Correlations with respect to the fourth harmonic, $\langle\cos(2\phi_{a}+2\phi_{b}-4\psi)\rangle$, are insensitive to the CME and can be used to estimate the magnitude of these background effects. In this thesis, we present results from charge-dependent correlations with respect to both the second and fourth harmonic event planes measured in Pb+Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV at the LHC using data from the ALICE detector. We also present calculations of the ratio of the fourth to second harmonics based on the blast-wave model, which serve as a baseline to understand how these background effects scale between one harmonic and another.

Author: Xiaofeng Luo
Publisher: Springer Nature
ISBN: 9811944415
Category : Science
Languages : en
Pages : 294

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This book highlights the discussions by renown researchers on questions emerged during transition from the relativistic heavy-ion collider (RHIC) to the future electron ion collider (EIC). Over the past two decades, the RHIC has provided a vast amount of data over a wide range of the center of mass energies. What are the scientific priorities, after RHIC is shut down and turned to the future EIC? What should be the future focuses of the high-energy nuclear collisions? What are thermodynamic properties of quantum chromodynamics (QCD) at large baryon density? Where is the phase boundary between quark-gluon-plasma and hadronic matter at high baryon density? How does one make connections from thermodynamics learned in high-energy nuclear collisions to astrophysical topics, to name few, the inner structure of compact stars, and perhaps more interestingly, the dynamical processes of the merging of neutron stars? While most particle physicists are interested in Dark Matter, we should focus on the issues of Visible Matter! Multiple heavy-ion accelerator complexes are under construction: NICA at JINR (4 ~ 11 GeV), FAIR at GSI (2 ~ 4.9 GeV SIS100), HIAF at IMP (2 ~ 4 GeV). In addition, the heavy-ion collision has been actively discussed at the J-PARC. The book is a collective work of top researchers from the field where some of the above-mentioned basic questions will be addressed. We believe that answering those questions will certainly advance our understanding of the phase transition in early universe as well as its evolution that leads to today's world of nature.