Long-range Two-particle Correlations of Strange Hadrons with Charged Particles in PPb and PbPb Collisions at LHC Energies

Long-range Two-particle Correlations of Strange Hadrons with Charged Particles in PPb and PbPb Collisions at LHC Energies
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Total Pages: 25
Release: 2015
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The measurements of two-particle angular correlations between an identified strange hadron ( K0s or [Lambda]/[Lambda]- ) and a charged particle, emitted in pPb collisions, are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 35 nb-1, were collected at a nucleon-nucleon center-of-mass energy (√sNN ) of 5.02 TeV with the CMS detector at the LHC. Our results are compared to semi-peripheral PbPb collision data at √sNN , covering similar charged-particle multiplicities in the events. The observed azimuthal correlations at large relative pseudorapidity are used to extract the second-order (v2) and third-order (v3) anisotropy harmonics of K0s and [Lambda]/[Lambda]- particles. These quantities are studied as a function of the charged-particle multiplicity in the event and the transverse momentum of the particles. For high-multiplicity pPb events, a clear particle species dependence of v2 and v3 is observed. For pT

Multiplicity and Rapidity Dependence of Strange Hadron Production in Pp, PPb, and PbPb Collisions at the LHC.

Multiplicity and Rapidity Dependence of Strange Hadron Production in Pp, PPb, and PbPb Collisions at the LHC.
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Release: 2016
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Measurements of strange hadron (K0s, Lambda + anti-Lambda, and Xi+ + Xi- ) transverse momentum spectra in pp, pPb, and PbPb collisions are presented over a wide range of rapidity and event charged-particle multiplicity. The data were collected with the CMS detector at the CERN LHC in pp collisions at sqrt(s) = 7 TeV, pPb collisions at sqrt(s[NN]) = 5.02 TeV, and PbPb collisions at sqrt(s[NN]) = 2.76 TeV. The average transverse kinetic energy is found to increase with multiplicity, at a faster rate for heavier strange particle species in all systems. At similar multiplicities, the difference in average transverse kinetic energy between different particle species is observed to be larger for pp and pPb events than for PbPb events. In pPb collisions, the average transverse kinetic energy is found to be slightly larger in the Pb-going direction than in the p-going direction for events with large multiplicity. The spectra are compared to models motivated by hydrodynamics.

Flow of [phi] Mesons in Proton-lead Collisions at the Large Hadron Collider with the Compact Muon Solenoid Detector

Flow of [phi] Mesons in Proton-lead Collisions at the Large Hadron Collider with the Compact Muon Solenoid Detector
Author: Mukund Madhav Varma
Publisher:
Total Pages: 75
Release: 2015
Genre:
ISBN:

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Measurements of two-particle angular correlations between unidentified charged particles and [phi]-mesons are shown over a wide pseudorapidity range ([delta] [eta] 2) in pPb collisions. The data, collected during 2013 pPb run at a nucleon-nucleon center-ofmass energy of 5.02 TeV with the CMS detector, corresponds to a total integrated luminosity of aproximately 35nb-1. [Phi]-mesons are reconstructed via their hadronic decay channel, [phi] -- K+K-, for high multiplicity events. The observed two-particle long range correlations are quantified by the second-order Fourier coefficients (v2) as a function of transverse momentum. The v2 of [phi]-mesons is compared to that of other identified particles, to study the mass ordering and quark number scaling effects in measurements of elliptic flow.

Strange and Non-Strange D-meson Production in pp, p-Pb, and Pb-Pb Collisions with ALICE at the LHC

Strange and Non-Strange D-meson Production in pp, p-Pb, and Pb-Pb Collisions with ALICE at the LHC
Author: Fabrizio Grosa
Publisher: Springer Nature
Total Pages: 227
Release: 2021-04-17
Genre: Science
ISBN: 3030711315

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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.

Nuclear Effects on the Transverse Momentum Spectra of Charged Particles in PPb Collisions at $\sqrt{s_{_\mathrm {NN}}}

Nuclear Effects on the Transverse Momentum Spectra of Charged Particles in PPb Collisions at $\sqrt{s_{_\mathrm {NN}}}
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Total Pages: 37
Release: 2015
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Transverse momentum spectra of charged particles are measured by the CMS experiment at the CERN LHC in pPb collisions at [arrow]"NN = 5.02 TeV, in the range 0.4

Azimuthal Anisotropy of Charged Particles at High Transverse Momenta in PbPb Collisions at Sqrt(s[NN]

Azimuthal Anisotropy of Charged Particles at High Transverse Momenta in PbPb Collisions at Sqrt(s[NN]
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Total Pages: 27
Release: 2012
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ISBN:

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The azimuthal anisotropy of charged particles in PbPb collisions at nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (pt) range up to approximately 60 GeV. The data cover both the low-pt region associated with hydrodynamic flow phenomena and the high-pt region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (v2) of the particles is extracted by correlating charged tracks with respect to the event-plane reconstructed by using the energy deposited in forward-angle calorimeters. For the six bins of collision centrality studied, spanning the range of 0-60% most-central events, the observed v2 values are found to first increase with pt, reaching a maximum around pt = 3 GeV, and then to gradually decrease to almost zero, with the decline persisting up to at least pt = 40 GeV over the full centrality range measured.

Evidence for Collectivity in Pp Collisions at the LHC.

Evidence for Collectivity in Pp Collisions at the LHC.
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Release: 2016
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Measurements of two- and multi-particle angular correlations in pp collisions at sqrt(s) = 5, 7, and 13 TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0 inverse picobarns (5 TeV), 6.2 inverse picobarns (7 TeV), and 0.7 inverse picobarns (13 TeV), were collected using the CMS detector at the LHC. The second-order (v[2]) and third-order (v[3]) azimuthal anisotropy harmonics of unidentified charged particles, as well as v[2] of K0 short and Lambda/anti-Lambda particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v[2] values of charged hadrons (mostly pions), K0 short, and Lambda/anti-Lambda, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pt~2 GeV/c. For 13 TeV data, the v[2] signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.