Systematic Azimuth Quadrupole and Minijet Trends from Two-particle Correlations in Heavy-ion Collisions PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Systematic Azimuth Quadrupole and Minijet Trends from Two-particle Correlations in Heavy-ion Collisions PDF full book. Access full book title Systematic Azimuth Quadrupole and Minijet Trends from Two-particle Correlations in Heavy-ion Collisions by David Kettler. Download full books in PDF and EPUB format.
Author: David Kettler
Publisher:
ISBN:
Category :
Languages : en
Pages : 284
Get Book Here
Book Description
Heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) produce a tremendous amount of data but new techniques are necessary for a comprehensive understanding of the physics behind these collisions. We present measurements from the STAR detector of both p[sub]t-integral and p[sub]t-differential azimuth two-particle correlations on azimuth (ø) and pseudorapidity (n) for unidentified hadrons in Au-Au collisions at [squareroot [super]sNN=62 and 200 GeV. The azimuth correlations can be fit to extract a quadrupole component---related to conventional v_2 measures---and a same-side peak. Both p[sub]t-integral and p[sub]t-differential results are presented as functions of Au-Au centrality.We observe simple universal energy and centrality trends for the p[sub]t-integral quadrupole component. p[sub]t-differential results can be transformed to reveal quadropole p[sub]t spectra that are nearly independent of centrality. A parametrization of the p[sub]t-differential quadrupole shows a simple p[sub]t dependence that can be factorized from the centrality and collision energy dependence above 0.75 GeV/c. Observed trends seem to be in conflict with standard hydrodynamic theories. Angular correlations contain jet-like structure wit most-probable hadron momentum ~1 GeV/c. For better comparison to RHIC data we analyze the energy scale dependence of fragmentation functions from e+-e− collisions on rapidity y. The results in a parameterization of fragmentation functions that enables extrapolation to low Q in order to describe fragment distributions at low transverse momentum p[sub]t in heavy ion collisions. We convert measured minimum-bias jet-like angular correlations to single-particle hadron yields and compare them with patron fragment yields inferred from spectrum hard components. We find that jet-like correlations in central 200 GeV Au-Au collisions correspond quantitatively to pQCD predictions, and the jet-correlated hadron yield comprises one third of the Au-Au final state in central collisions. These observations conflict with the claims of "jet quenching" at RHIC.
Author: David Kettler
Publisher:
ISBN:
Category :
Languages : en
Pages : 284
Get Book Here
Book Description
Heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) produce a tremendous amount of data but new techniques are necessary for a comprehensive understanding of the physics behind these collisions. We present measurements from the STAR detector of both p[sub]t-integral and p[sub]t-differential azimuth two-particle correlations on azimuth (ø) and pseudorapidity (n) for unidentified hadrons in Au-Au collisions at [squareroot [super]sNN=62 and 200 GeV. The azimuth correlations can be fit to extract a quadrupole component---related to conventional v_2 measures---and a same-side peak. Both p[sub]t-integral and p[sub]t-differential results are presented as functions of Au-Au centrality.We observe simple universal energy and centrality trends for the p[sub]t-integral quadrupole component. p[sub]t-differential results can be transformed to reveal quadropole p[sub]t spectra that are nearly independent of centrality. A parametrization of the p[sub]t-differential quadrupole shows a simple p[sub]t dependence that can be factorized from the centrality and collision energy dependence above 0.75 GeV/c. Observed trends seem to be in conflict with standard hydrodynamic theories. Angular correlations contain jet-like structure wit most-probable hadron momentum ~1 GeV/c. For better comparison to RHIC data we analyze the energy scale dependence of fragmentation functions from e+-e− collisions on rapidity y. The results in a parameterization of fragmentation functions that enables extrapolation to low Q in order to describe fragment distributions at low transverse momentum p[sub]t in heavy ion collisions. We convert measured minimum-bias jet-like angular correlations to single-particle hadron yields and compare them with patron fragment yields inferred from spectrum hard components. We find that jet-like correlations in central 200 GeV Au-Au collisions correspond quantitatively to pQCD predictions, and the jet-correlated hadron yield comprises one third of the Au-Au final state in central collisions. These observations conflict with the claims of "jet quenching" at RHIC.
Author: V. N. Russkikh
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Author: Eric Vazquez
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Measurements at the Relativistic Heavy Ion Collider (RHIC) have provided indirect measurements of jets in a heavy ion environment using the two- particle correlation method in the presence of a high-pT particle. These measurements have offered insight into the formation of a new state of dense nuclear matter called the Quark-Gluon Plasma (QGP) through the observation of jet quenching. However, the two-particle methodology has also shown to be biased towards di-jet production near the surface of the medium being created. Here, a detailed study using the PHENIX detector is provided, in an attempt to measure a more accurate jet-induced two-particle correlation measurement than previously published and to reduce the bias observed in two-particle correlation measurements. The reduction in surface bias emission is performed via the requirement of two antipodal high-pT particles (a.k.a. "2+1" correlation) in an attempt to control the production point of the di-jet. The measurements made in Au+Au collisions when compared to p+p collisions show that the method provides additional sensitivity to the jet quenching previously observed in two-particle correlation method.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Jets have been studied in high energy heavy ion collisions by measuring the angular correlation between particles at high transverse momentum. Differences in the yield and shape of the angular correlations as a function of system size give information on the medium produced in the collision. Such modifications can be used to infer the presence of a Quark-Gluon Plasma phase, wherein parton degrees of freedom are manifest over nuclear rather than nucleonic scales. In the present work, two-particle correlations were studied in \(d+Au\) and \(Au+Au\) collisions at \(\sqrt{s_{NN}}\) = 200 GeV measured by the STAR experiment at RHIC. The technique was extended to include pseudo-rapidity, permitting jets to be characterised in two-dimensions, and enabling the jet shape to be studied in greater detail. Corrections were developed for the incomplete detector acceptance and finite two-track resolution. Both unidentified and identified particle correlations were studied, using charged tracks and neutral strange particles \(\Lambda, \overline{\Lambda}\), and \(K^0_{Short}\) reconstructed from their characteristic \(V\)0 decay topology. The focus of the analysis was the correlation peak centred at zero azimuthal separation, which is significantly enhanced in central \(Au+Au\) collisions compared to lighter systems. The modified peak was found to comprise a jet-like peak broadened in the pseudo-rapidity direction, sitting atop a long range pseudo-rapidity correlation. The former is suggestive of jet modification by the medium, and the latter may indicate a medium response to jets. Correlations with identified particles indicated the modified same side peak may in part be formed from particles originating from the underlying event.
Author: William Allen Zajc
Publisher:
ISBN:
Category :
Languages : en
Pages : 344
Get Book Here
Book Description
Author: Abinash Pun
Publisher:
ISBN:
Category : Heavy ions
Languages : en
Pages :
Get Book Here
Book Description
The possible presence of Quark-Gluon Plasma (QGP), the new state of matter created at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) in Au+Au and Pb+Pb collisions, is currently under investigation for smaller collisions systems such as light-heavy ions and even p+p. Long range angular correlations of particles produced in p+Pb, p+Au, d+Au, and 3He+Au, show evidence of QGP collective flow, but another signature, QGP-induced jet energy loss effects has not been identified. To address this situation, in this dissertation, a recently introduced observable RI is employed in light-heavy ion collisions. RI is derived from two-particle correlation method commonly used to study jet modification from energy loss in Au+Au.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
The authors have used a nine-parameter expanding source model that includes special relativity, quantum statistics, resonance decays, and freeze-out on a realistic hypersurface in spacetime to analyze in detail invariant [pi][sup +], K[sup +], and K[sup [minus]] one-particle multiplicity distributions and [pi][sup +] and [pi][sup [minus]] two-particle correlations in nearly central collisions of Pb + Pb at p[sub lab]/A = 158 GeV/c. These studies confirm an earlier conclusion for nearly central collisions of Si + Au at p[sub lab]/A = 14.6 GeV/c that the freeze-out temperature is less than 100 meV and that both the longitudinal and transverse collective velocities -- which are anti-correlated with the temperature -- are substantial. The authors also reconciled their current results with those of previous analyses that yielded a much higher freeze-out temperature of approximately 140 meV for both Pb + Pb collisions at p[sub lab]/A = 158 GeV/c and other reactions. One type of analysis was based upon the use of a heuristic equation that neglects relativity to extrapolate slope parameters to zero particle mass. Another type of analysis utilized a thermal model in which there was an accumulation of effects from several approximations. The future should witness the arrival of much new data on invariant one-particle multiplicity distributions and two-particle correlations as functions of bombarding energy and/or size of the colliding nuclei. The proper analysis of these data in terms of a realistic model could yield accurate values for the density, temperature, collective velocity, size, and other properties of the expanding matter as it freezes out into a collection of noninteracting hadrons. A sharp discontinuity in the value of one or more of these properties could conceivably be the long-awaited signal for the formation of a quark-gluon plasma or other new physics.
Author: Raimond Johannes Maria Snellings
Publisher:
ISBN: 9789039316344
Category :
Languages : en
Pages : 91
Get Book Here
Book Description
Author: Yadav Pandit
Publisher:
ISBN:
Category : Anisotropy
Languages : en
Pages : 160
Get Book Here
Book Description
STAR (Solenoidal Tracker At RHIC) is one of two large detectors along the ring of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Experiments that collide heavy nuclei at high energy have been taking data at RHIC since the year 2000. The main goal of RHIC has been to search for a new phase of matter called the Quark Gluon Plasma (QGP), and to determine its properties, including the phase diagram that governs the relationship between QGP and more conventional hadronic matter. This dissertation has a particular focus on analysis of STAR measurements of the anisotropy of particle emission over a range of colliding energies, and these particular measurements are made possible by a unique application of a detector subsystem called Beam-Beam Counters (BBCs), which are placed close to the beam lines on both sides of the collision region. This project has involved development of software that uses the hit pattern of charged particles in the BBCs to determine the collision reaction plane, for use in measurements of anisotropy. Anisotropic flow sheds light on the early partonic system, and according to models, is minimally distorted during the post-partonic stages of the collision. In this anisotropic flow analysis, the estimated reaction plane of each event is reconstructed using the BBC signals, which have a large rapidity gap between them. There is also a large rapidity gap between each BBC and the STAR Time Projection Chamber (the main STAR subsystem for measuring particle tracks). These large rapidity gaps allow us to measure correlations relative to the reaction plane with the least possible systematic error from what is known as "non-flow", i.e., background correlations unrelated to the reaction plane. Flow correlations are normally reported in terms Fourier coefficients, v1, v2, etc. Di- rected flow is quantified by the first harmonic (v1) in the Fourier expansion of the particle's azimuthal distribution with respect to the reaction plane. Elliptic flow is the name given to the second harmonic (v2), and triangular flow is the name for the third harmonic (v3). These harmonic coefficients carry information on the very early stages of the collision. The v1 component is emphasized in this dissertation, and the BBC information that is a unique feature of this work is especially important for v1 measurements. Until recently, higher-order odd harmonics were overlooked. These odd flow harmonics carry valuable information about the initial-state fluctuations of the colliding system. This dissertation includes a study of the flow harmonic related to dipole asymmetry and triangularity in the initial geometry.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7
Get Book Here
Book Description
Two particle correlation measurements for {ital Si-A} and {ital Au- Au} collisions from Brookhaven E859 and E866 are discussed. These measurements allow us, with some interpretation, to deduce the size of the participant region in a heavy ion collision. We show that various source parameterizations yield consistent results and we explore the dependence of the apparent source size on the pion yield.
