Relative Yields of Antiparticles to Particles in Au+Au Collisions at 130 and 200 GeV Per Nucleon Pair

Relative Yields of Antiparticles to Particles in Au+Au Collisions at 130 and 200 GeV Per Nucleon Pair
Author: Kristján Herlache Gulbrandsen
Publisher:
Total Pages: 131
Release: 2004
Genre:
ISBN:

Au+Au collisions at [square root of] [superscript]s nn = 130 and 200 GeV at the Relativistic Heavy Ion Collider have opened a new energy regime for studying nucleus-nucleus collisions. A search for the formation of a phase of matter in which quarks and gluons interact strongly over an extended deconfined volume is of primary importance. The PHOBOS detector was constructed to measure many observables at RHIC. The primary subsystem used in this analysis is the PHOBOS spectrometer. The spectrometer is a multiplane silicon pad detector which detects particles traversing its pads as they propagate through a strong magnetic field. The hit positions are used along with energy loss information in the silicon pads to determine both the momentum and velocity of the particles, allowing for the identification of the particle species. One of the most basic pieces of information to be determined is the baryochemical potential of the system. This information has been determined through the measurement of the relative yields of antiparticles to particles in RHIC collisions ... These values are compared to model predictions and are used to evaluate the contribution of baryon transport relative to particle production in determining the yields of baryon at midrapidity in central Au+Au collisions at RHIC energies.

Identified Particle Transverse Momentum Distributions from AU + AU Collisions at 62.4 GeV Per Nucleon Pair

Identified Particle Transverse Momentum Distributions from AU + AU Collisions at 62.4 GeV Per Nucleon Pair
Author: Conor Henderson
Publisher:
Total Pages: 322
Release: 2005
Genre:
ISBN:

Transverse momentum (PT) distributions for pions, kaons, protons and antiprotons have been measured near mid-rapidity for Au+Au collisions at sNN = 62.4 GeV using the PHOBOS detector at the Relativistic Heavy-Ion Collider (RHIC) in Brookhaven National Laboratory. Particle identification is performed using the PHOBOS Time-of-Flight plastic scintillator walls and specific energy loss in the multi-layer silicon Spectrometer, which is also used for track reconstruction and momentum-determination. The spectra are corrected for all detector-dependent effects, including feed-down from weak decays. At PT 3 GeV/c, protons are measured to be the dominant species of charged hadrons and scale much faster with respect to collision centrality than mesons. This behaviour at 62.4 GeV is found to be remarkably similar to that observed in Au+Au collisions at 200 GeV, an interesting observation which should serve as an important constraint on the various mechanisms which have been proposed to describe particle production over this PT range. Baryon stopping, the transport of baryon number from intial beam rapidity, is explored through the net proton (p - p) yields at mid-rapidity. These results fill a large gap between the SPS and higher RHIC energies and as such form an important set of data for comparing to models of baryon transport mechanisms.

Proceedings of the Fifth Latin American Symposium, High Energy Physics, Lima, Peru, 12-17 July 2004

Proceedings of the Fifth Latin American Symposium, High Energy Physics, Lima, Peru, 12-17 July 2004
Author: Carlos Javier Solano Salinas
Publisher: World Scientific
Total Pages: 374
Release: 2006
Genre: Computers
ISBN: 9812567313

This proceedings is the fifth in the series of Latin American symposiums focusing on the development, refinement and applications of high energy physics. As the principal meetings for the physics community in Latin America, it encourages collaborations and the exchange of ideas with the international physics communities. This particular symposium was also a dedication to the memory of Dr Luis Masperi.

Proton and Produced Particle Distributions from Au+Au Collisions at 11.6 A GeV/c

Proton and Produced Particle Distributions from Au+Au Collisions at 11.6 A GeV/c
Author:
Publisher:
Total Pages: 6
Release: 1994
Genre:
ISBN:

The highest net baryon density possible in the laboratory--up to ten times normal nuclear density--is expected in the central region of collisions of heavy nuclei (A ≈ 200) at energies near 10 GeV per nucleon. The transverse energy (E{sub T}) distribution, as well as yields of identified particles (?, K+ and protons), from 197Au + 197Au at 11.64A GeV/c are presented. Two key observations are a large degree of proton s̀̀topping, ̀̀indicating multiple scatterings of the incident nucleons, and a proportional relationship of the pion production to the number of participating nucleons. Strangeness enhancement, a proposed signature of the quark-gluon plasma, is studied via the K+/?+ ratio, which achieves the value of 21% without a strong centrality dependence. Comparisons to similar data taken with a 14.6A GeV/c beam of 28Si are made.

Strange Particle and Antiproton Production in S + Nucleus Collisions at 200 GeV

Strange Particle and Antiproton Production in S + Nucleus Collisions at 200 GeV
Author:
Publisher:
Total Pages: 6
Release: 1994
Genre:
ISBN:

Central S+S, S+Ag and S+Au collisions at 200 GeV/nucleon were studied in experiment NA35 at the CERN SPS. Recent results on strange particle production as well as the preliminary results on antiproton production are presented and discussed. Enhanced strangeness production relative to the pion and antiproton yields is observed in nucleus-nucleus collisions relative to p-p and p-A. Microscopic string models fail to consistently describe the available set of data.

Scaling Properties of Hyperon Production in Au + Au Collisions at Sqrt SNN

Scaling Properties of Hyperon Production in Au + Au Collisions at Sqrt SNN
Author:
Publisher:
Total Pages:
Release: 2006
Genre:
ISBN:

We present the scaling properties of Lambda, Xi, and their anti-particles produced at mid-rapidity in Au+Au collisions at RHIC at psNN = 200 GeV. The yield of multi-strange baryons per participant nucleon increases from peripheral to central collisions more rapidly than the Lambda yield, which appears to correspond to an increasing strange quark density of matter produced. The value of the strange phase space occupancy factor gamma s, obtained from a thermal model fit to the data, approaches unity for the most central collisions. We also show that the nuclear modification factors, RCP, of Lambda and Xi are consistent with each other and with that of protons in the transverse momentum range2.0

Measurement of Heavy Flavor Yield and Azimuthal Anisotropy at Forward Angles in Cu + Au Collisions at a Center-of-mass Collision Energy Per Nucleon of 200 GeV

Measurement of Heavy Flavor Yield and Azimuthal Anisotropy at Forward Angles in Cu + Au Collisions at a Center-of-mass Collision Energy Per Nucleon of 200 GeV
Author: Brandon Kyle Schmoll
Publisher:
Total Pages: 175
Release: 2017
Genre: Heavy ion collisions
ISBN:

Heavy flavor quarks are produced early in heavy ion collisions and will experience the full evolution of the Quark Gluon Plasma (QGP). Measurements at forward rapidity may be influenced as much, or more, by the cold nuclear matter effects as by the hot nuclear matter effects associated with a QGP. As the medium evolves, the initial spatial anisotropy of participants is converted to an azimuthal anisotropy in the momentum space of outgoing particles. Therefore, the momentum spectra modification and anisotropy parameters provide useful information about the heavy quark interaction with the bulk medium. Asymmetric heavy ion collisions, such as Cu+Au, provide a unique geometry with which to study the dynamics of the heavy quarks, relative to that in symmetric collisions. In particular, asymmetries in the yields between the Cu-going and Au-going directions may help unentangle the so-called cold nuclear matter effects from the hot nuclear matter effects indicative of a QGP. In addition, the parameters v2 and v3 in asymmetric collisions may be modified relative to the symmetric collisions due to the unique geometry provided in mid-central Cu+Au collisions. This dissertation presents the measurement of the yield and azimuthal anisotropy of single muons originating from heavy flavor decays in [square root of]SNN [center-of-mass energy per nucleon] = 200 GeV Cu+Au collisions.