Observation and Studies of Jet Quenching in PbPb Collisions at Nucleon-nucleon Center-of-mass Energy

Observation and Studies of Jet Quenching in PbPb Collisions at Nucleon-nucleon Center-of-mass Energy PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 26

Get Book Here

Book Description
Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the CMS detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 inverse microbarns. Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse momentum is observed, consistent with jet quenching. The observed effect extends from the lower cut-off used in this study (jet transverse momentum = 120 GeV/c) up to the statistical limit of the available data sample (jet transverse momentum approximately 210 GeV/c). Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet.

Observation and Studies of Jet Quenching in PbPb Collisions at Nucleon-nucleon Center-of-mass Energy

Observation and Studies of Jet Quenching in PbPb Collisions at Nucleon-nucleon Center-of-mass Energy PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 26

Get Book Here

Book Description
Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the CMS detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 inverse microbarns. Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse momentum is observed, consistent with jet quenching. The observed effect extends from the lower cut-off used in this study (jet transverse momentum = 120 GeV/c) up to the statistical limit of the available data sample (jet transverse momentum approximately 210 GeV/c). Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet.

Structure of Nucleon Excited States from Lattice QCD

Structure of Nucleon Excited States from Lattice QCD PDF Author: Finn M. Stokes
Publisher: Springer Nature
ISBN: 3030257223
Category : Science
Languages : en
Pages : 237

Get Book Here

Book Description
Quantum Chromodynamics (QCD) describes the interactions between elementary quarks and gluons as they compose the nucleons at the heart of atomic structure. The interactions give rise to complexity that can only be examined via numerical simulations on supercomputers. This work provides an introduction to the numerical simulations of lattice QCD and establishes new formalisms relevant to understanding the structure of nucleons and their excited states. The research opens with an examination of the non-trivial QCD vacuum and the emergence of “centre domains.” The focus then turns to establishing a novel Parity-Expanded Variational Analysis (PEVA) technique solving the important problem of isolating baryon states moving with finite momentum. This seminal work provides a foundation for future calculations of baryon properties. Implementation of the PEVA formalism discloses important systematic errors in conventional calculations and reveals the structure of nucleon excited states from the first principles of QCD for the first time.

Study of Jet Quenching with Z+jet Correlations in PbPb and Pp Collisions at $\sqrt{s_{NN}}$

Study of Jet Quenching with Z+jet Correlations in PbPb and Pp Collisions at $\sqrt{s_{NN}}$ PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
The production of jets in association with Z bosons, reconstructed via the mu+mu- and e+e- decay channels, is studied in pp and, for the first time, in PbPb collisions. Both data samples were collected by the CMS experiment at the LHC, at a center-of-mass energy of 5.02 TeV. The PbPb collisions were analyzed in the 0-30% centrality range. The back-to-back azimuthal alignment was studied in both pp and PbPb collisions for Z bosons with transverse momentum ptz> 60 GeV/c and a recoiling jet with ptj> 30 GeV/c. The pt imbalance, xjz= ptj/ptz, as well as the average number of jet partners per Z, rjz, were studied in intervals of ptz, in both pp and PbPb collisions. The rjz is found to be smaller in PbPb than in pp collisions, which suggests that in PbPb collisions a larger fraction of partons, associated with the Z bosons, lose energy and fall below the 30 GeV/c ptj threshold.

Study of Jet Quenching Using [gamma]-jet Events in Heavy Ion Collisions at 2.76TeV

Study of Jet Quenching Using [gamma]-jet Events in Heavy Ion Collisions at 2.76TeV PDF Author: Yongsun Kim (Ph. D.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 159

Get Book Here

Book Description
The kinematic correlations of isolated-[gamma]+jet scatterings in proton-proton and lead-lead collisions at centre-of-mass energy of 2.76TeV per nucleon pair are studied for the investigation of the jet quenching phenomena in hot and dense QCD medium. The analysis uses collision data delivered by the LHC and recorded by CMS detector at CERN. The angular correlation, the transverse momentum ratio and the rate of mono-photon events are measured and their dependence on the collisional impact parameter is examined in lead-lead collision. The results of proton-proton collisions are used as the reference to which the lead-lead results are compared. Significant energy loss of jets induced by the hot and dense medium, and its gradual rise in correlation to the size of the medium are observed in lead-lead collisions, while a modification of the direction of jet axis is not detected.

FormaMente n. 1-2/2012

FormaMente n. 1-2/2012 PDF Author: AA. VV.
Publisher: Gangemi Editore spa
ISBN: 8849274335
Category : Technology & Engineering
Languages : en
Pages : 284

Get Book Here

Book Description
RICERCA Jet momentum dependence of jet quenching in PbPb collisions at SNN = 2.76 TeV The CMS Collaboration Modeling the metaverse: a theoretical model of effective team collaboration in 3D virtual environments Sarah van der Land, Alexander P. Schouten, Bart van den Hooff, Frans Feldberg The capture of moving object in video image Weina Fu, Zhiwen Xu, Shuai Liu, Xin Wang, Hongchang Ke Visual metaphors in virtual worlds. The example of NANEC 2010/11 Dolors Capdet Von Neuromancer zu Second Life. Raumsimulationen im Cyberspace Steffen Krämer APPLICAZIONI APPLICAZIONI Sensor models and localization algorithms for sensor networks based on received signal strength Fredrik Gustafsson, Fredrik Gunnarsson, David Lindgren Interactive lab to learn radio astronomy, microwave & antenna engineering at the Technical University of Cartagena José Luis Gómez-Tornero, David Cañete-Rebenaque, Fernando Daniel Quesada-Pereira, Alejandro Álvarez-Melcón

Future Of The Large Hadron Collider, The: A Super-accelerator With Multiple Possible Lives

Future Of The Large Hadron Collider, The: A Super-accelerator With Multiple Possible Lives PDF Author: Oliver Bruning
Publisher: World Scientific
ISBN: 9811280193
Category : Science
Languages : en
Pages : 455

Get Book Here

Book Description
The Large Hadron Collider (LHC) is the highest energy collider ever built. It resides near Geneva in a tunnel 3.8m wide, with a circumference of 26.7km, which was excavated in 1983-1988 to initially house the electron-positron collider LEP. The LHC was approved in 1995, and it took until 2010 for reliable operation. By now, a larger set of larger integrated luminosities have been accumulated for physics analyses in the four collider experiments: ATLAS, CMS, LHCb and ALICE.The LHC operates with an extended cryogenic plant, using a multi-stage injection system comprising the PS and SPS accelerators (still in use for particle physics experiments at lower energies). The beams are guided by 1232 superconducting high field dipole magnets.Intense works are underway in preparation of the High Luminosity LHC, aimed at upgrading the LHC and detectors for collecting ten times more luminosity, and extending the collider life to the early 2040's. So far, the (HL-)LHC project represents a cumulation of around one hundred thousand person-years of innovative work by technicians, engineers, and physicists from all over the world; probably the largest scientific effort ever in the history of humanity. The book is driven by the realisation of the unique value of this accelerator complex and by the recognition of the status of high energy physics, described by a Standard Model — which still leaves too many questions unanswered to be the appropriate theory of elementary particles and their interactions.Following the Introduction are: three chapters which focus on the initial decade of operation, leading to the celebrated discovery of the Higgs Boson, on the techniques and physics of the luminosity upgrade, and finally on major options - of using the LHC in a concurrent, power economic, electron-hadron scattering mode, when upgraded to higher energies or eventually as an injector for the next big machine. The various technical and physics chapters, provided by 61 authors, characterise the fascinating opportunities the LHC offers for the next two decades ahead (possibly longer), with the goal to substantially advance our understanding of nature.

Study of Z Boson Production in PbPb Collisions at Nucleon-nucleon Centre of Mass Energy

Study of Z Boson Production in PbPb Collisions at Nucleon-nucleon Centre of Mass Energy PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

Get Book Here

Book Description
A search for Z bosons in the mu+̂mu-̂ decay channel has been performed in PbPb collisions at a nucleon-nucleon centre of mass energy = 2.76 TeV with the CMS detector at the LHC, in a 7.2 inverse microbarn data sample. The number of opposite-sign muon pairs observed in the 60--120 GeV/c2̂ invariant mass range is 39, corresponding to a yield per unit of rapidity (y) and per minimum bias event of (33.8 +/- 5.5 (stat) +/- 4.4 (syst)) 10{̂-8}, in the.

Observation and Studies of Jet Quenching in Pp, Pa and Aa Collisions

Observation and Studies of Jet Quenching in Pp, Pa and Aa Collisions PDF Author: Vinod K Kancherla
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 92

Get Book Here

Book Description
We provide the important results from the proton0́3proton, proton0́3nucleus,nucleus0́3nucleus collision from the RHIC and LHC colliders, emphasizing jet-quenching in central collisions. We analyzed the behavior of nuclear modifi-cation factor and azimuthal anisotropies in dihadron correlations in variouscollisions at different beam energies. We analyzed the Inclusive transversemomentum spectra of charged particles in multiple detectors. The data fromfour of the RHIC detectors (STAR, PHENIX, PHOBOS, BRAHMS) and two of the LHC detectors (ALICE, CMS) are presented and compared forthe analysis. Initial conditions and final state effects of the high-energyheavy-ion collisions have been described. Both the RHIC and LHC data areconsistent with theoretical perturbative calculations incorporating the par-tonic energy loss in color-dense QCD matter, and this suggests formation ofa deconfined QGP phase in these high energy collisions.

Modification of Jet Shapes in PbPb Collisions at $\sqrt {s_{NN}}

Modification of Jet Shapes in PbPb Collisions at $\sqrt {s_{NN}} PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 21

Get Book Here

Book Description
The first measurement of jet shapes, defined as the fractional transverse momentum radial distribution, for inclusive jets produced in heavy-ion collisions is presented. Data samples of PbPb and pp collisions, corresponding to integrated luminosities of 150 inverse microbarns and 5.3 inverse picobarns respectively, were collected at a nucleon-nucleon centre-of-mass energy of sqrt(s[NN]) = 2.76 TeV with the CMS detector at the LHC. The jets are reconstructed with the anti-kt algorithm with a distance parameter R=0.3, and the jet shapes are measured for charged particles with transverse momentum pt> 1 GeV. The jet shapes measured in PbPb collisions in different collision centralities are compared to reference distributions based on the pp data. A centrality-dependent modification of the jet shapes is observed in the more central PbPb collisions, indicating a redistribution of the energy inside the jet cone. This measurement provides information about the parton shower mechanism in the hot and dense medium produced in heavy-ion collisions.

Long-range and Short-range Dihadron Angular Correlations in Central PbPb Collisions at a Nucleon-nucleon Center of Mass Energy of 2.76 TeV.

Long-range and Short-range Dihadron Angular Correlations in Central PbPb Collisions at a Nucleon-nucleon Center of Mass Energy of 2.76 TeV. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 30

Get Book Here

Book Description
First measurements of dihadron correlations for charged particles are presented for central PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV over a broad range in relative pseudorapidity, Delta(eta), and the full range of relative azimuthal angle, Delta(phi). The data were collected with the CMS detector, at the LHC. A broadening of the away-side (Delta(phi) approximately pi) azimuthal correlation is observed at all Delta(eta), as compared to the measurements in pp collisions. Furthermore, long-range dihadron correlations in Delta(eta) are observed for particles with similar phi values. This phenomenon, also known as the "ridge", persists up to at least.