arXiv subjects

J. L. Nagle

Publications and source records attributed to J. L. Nagle.

44 records · Page 3Linked to original sources

arXiv2002

Heavy Ion Experiments at RHIC: The First Year

We present a written version of four lectures given at the NATO Advanced Study Institute on "CD Perspectives on Hot and Dense Matter"in Cargese, Corsica during August, 2001. Over the last year the first exciting results from the Relativistic Heavy Ion Collider (RHIC) and the four experiments BRAHMS, PHENIX, PHOBOS, and STAR have been presented. In these lectures we review the state of RHIC and the experiments and the most exciting current results from Run I which took place in 2000. A complete review is not possible yet with many key results still preliminary or to be measured in Run II, which is currently underway, and thus the emphasis will be on the approach experimentalists have taken to address the fundamental physics issues of the field. We have not attempted to update the RHIC results for this proceedings, but rather present it as a snapshot of what was discussed in the workshop. The field is developing very quickly, and benefits greatly from contact and discussions between the different approaches of experimentalists and theorists.

nucl-ex↗

arXiv2001

Strangeness Production as a Diagnostic Tool for Understanding Heavy Ion Reactions

Strangeness production has long been proposed as a diagnostic tool for understanding the dynamics of relativistic heavy ion collisions. In this presentation we review the traditional picture of strangeness enhancement as a signature for quark-gluon plasma formation. We then review, in order, some experimental data on strange particle production in $e^{+}e^{-}$, $pp$, $p\bar{p}$, proton-nucleus and nucleus-nucleus collisions. This is not a comprehensive review, but rather an emphasis of a few significant points. Any clear interpretation of strange particle yields measured in heavy ion reactions is impossible without a physical understanding of the production mechanisms in elementary particle collisions.

hep-ph↗

arXiv2001

First results from RHIC: What are they telling us?

The Relativistic Heavy Ion Collider (RHIC) facility at Brookhaven National Laboratory is the first accelerator specifically constructed for the study of very hot and dense nuclear matter. At sufficiently high temperature, nuclear matter is expected to undergo a phase transition to a quark-gluon plasma. It is the specific goal of the field to study the nature of this plasma and understand the phase transitions between different states. The RHIC accelerator along with four experiments BRAHMS, PHENIX, PHOBOS, and STAR were commissioned last year with first collisions occurring in June 2000. Presented here are the first results from low luminosity beam in Run I. They are a glimpse of the wealth of physics to be extracted from the RHIC program over the next several years.

nucl-ex↗

arXiv1999

E864: Experimental Results on Exotic Nuclei and Rare Probes

Experiment 864 at the BNL-AGS was designed to search for exotic states of strange quark matter and other rare composite particles. The experiment was commissioned in 1994 and completed its final run in 1998. Here, we present an overview of the experimental results for the production of light nuclei up to A=7, antiprotons and antideuterons, hypernuclei and production limits on new states of quark matter.

nucl-ex↗

arXiv1999

Initial State Energy Loss Dependence of J/Psi and Drell-Yan in Relativistic Heavy Ion Collisions

We present a Glauber-based study of J/Psi and Drell-Yan yields in nucleus-nucleus collisions. Using this approach, we have investigated the impact of energy loss by the colliding nuclei on observed yields and transverse momentum spectra of J/Psi and Drell-Yan. These studies permit an assessment of the importance of initial state energy loss in relation to "anomalous" J/Psi suppression.

nucl-th↗

arXiv1998

Geometric Parameterization of $J/Ψ$ Absorption in Heavy Ion Collisions

We calculate the survival probability of $J/Ψ$ particles in various colliding systems using a Glauber model. An analysis of recent data has reported a $J/Ψ$-nucleon breakup cross section of 6.2$\pm$0.7 mb derived from an exponential fit to the ratio of $J/Ψ$ to Drell-Yan yields as a function of a simple, linearly-averaged mean path length through the nuclear medium. Our calculations indicate that, due to the nature of the calculation, this approach yields an apparent breakup cross section which is systematically lower than the actual value.

nucl-th↗

arXiv1997

Search for Charged Strange Quark Matter Produced in 11.5 A GeV/c Au + Pb Collisions

We present results of a search for strange quark matter (strangelets) in 11.5 A GeV/c Au+Pb collisions from the 1994 and 1995 runs of experiment E864 at Brookhaven's AGS. We observe no strangelet candidates and set a 90% confidence level upper limit of approximately 3x10**-8 per 10% central interaction for the production of |Z|=1 and |Z|=2 strangelets over a large mass range and with metastable lifetimes of about 50 ns or more. These results place constraints primarily on quark-gluon plasma based production models for strangelets.

nucl-ex↗

arXiv1995

New Scaling Law for Deuteron Production in Ultra-Relativistic Nucleus Nucleus Collisions

Deuteron production in S and Pb induced collisions at beam energies of 200 and 160 AGeV is studied in the framework of the transport theoretical approach RQMD. Strong transverse flow invalidates the differential coalescence formula in momentum space. The transverse momentum integrated $d$ yields scale in a broad rapidity interval with the squared proton densities and inversely with the produced particle rapidity densities. This kind of scaling can be linked to constant relative sizes of nucleon and pion sources at freeze-out. With increasing projectile mass the nucleon source blows up stronger than the pion source. As a result, the scaled deuteron densities drop in central Pb+Pb collisions by 15 percent as compared to S induced reactions.

nucl-th↗