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in subjects: "Heavy Ion Reactions"

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Particle identification in ultrarelativistic nuclear collisions

The role of particle identification (PID) in both fixed-target and colliding-beam studies of ultrarelativistic nuclear (URN) collisions is examined. The demands placed on the PID systems by peculiarities of URN collisions, such as large multiplicities and the need for simultaneous measurement of a number of observables, are discussed. A variety of PID techniques are reviewed, with emphasis on their applicability and efficiency in the environment of such collisions. Two examples of PID as incorp… more

Date: April 1, 1986

Creator: DiGiacomo, N.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Pion correlations as a function of atomic mass in heavy ion collisions

The method of two pion interferometry was used to obtain source-size and lifetime parameters for the pions produced in heavy ion collisions. The systems used were 1.70 {center dot} A GeV {sup 56}Fe + Fe, 1.82 {center dot} A GeV {sup 40}Ar + KCl and 1.54 {center dot} A GeV {sup 93}Nb + Nb, allowing for a search for dependences on the atomic number. Two acceptances (centered, in the lab., at {approximately} 0{degrees} and 45{degrees}) were used for each system, allowing a search for dependences o… more

Date: November 26, 1989

Creator: Chacon, A.D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Fifth high-energy heavy-ion study

This was the fifth of a continuing series of summer studies held at LBL to discuss high energy heavy ion collisions. Recently, a similar meeting has been held on alternate years at GSI (Darmstadt); and, in 1979, we held a meeting at LBL exclusively devoted to ultra-relativistic nuclear collisions. Two new features distinguish this study from earlier meetings in the series. First, the energy range for discussion was broadened by including collisions from about 20 MeV/nucleon to the highest avail… more

Date: October 1, 1981

Item Type: Article

Partner: UNT Libraries Government Documents Department

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/sup 16/O + /sup 40/Ca inelastic scattering and the elastic scattering wave function

The /sup 16/O + /sup 40/Ca inelastic scattering has been measured at 60-MeV incident energy, and evidence has been found in support of an explicit coupling between direct and elastic channels. The measurements were extended over a large angular range and in particular to very forward angles. The ratio of cross sections between extreme forward and backward angles proved very useful in studying the underlying reaction mechanism.

Date: January 1, 1977

Creator: Rehm, K.E.; Henning, W.; Erskine, J.R. & Kovar, D.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Di-leptons at the Bevalac

Recent results on the production of di-leptons measured by the Di-Lepton-Spectrometer (DLS) collaboration are discussed. Results are reported from observations made on p /plus/ Be collisions with proton beams from 1.0 to 4.9 GeV and on Ca collisions with calcium beams of 1.0 to 2.0 GeV/A. The shape of the distributions are similar to that at higher energies. The low mass cross section appears to be explained by ..pi..-..pi.. annihilation, but detailed calculations are needed to substantiate tha… more

Date: March 1, 1988

Creator: Matis, H.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Selective population of high-j states via heavy-ion-induced transfer reactions

One of the early hopes of heavy-ion-induced transfer reactions was to populate states not seen easily or at all by other means. To date, however, I believe it is fair to say that spectroscopic studies of previously unknown states have had, at best, limited success. Despite the early demonstration of selectivity with cluster transfer to high-lying states in light nuclei, the study of heavy-ion-induced transfer reactions has emphasized the reaction mechanism. The value of using two of these react… more

Date: January 1, 1982

Creator: Bond, P.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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What can HELIOS tell us on phase transition of nuclear matter

Transverse energy (E/sub t/) distributions and P/sub t/ spectra of negative particles and photons measured by the HELIOS experiment in 200 GeVN and 60 GeVN oxygen-nucleus reactions are presented. The E/sub t/ distributions are compared to a geometrical parametrization and a Montereverse arrowCarlo calculation, particle spectra to the proton-nucleus reaction case. The comparisons show that yet the results can be understood without assuming quark-gluon plasma formation. A discussion is made based… more

Date: January 1, 1987

Creator: En'yo, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Pseudorapidity distributions and correlations in central sup 16 O interactions at 200 A GeV

Whether or not adequate energy densities for a transition to the Quark-Gluon Plasma (QGP) phase are possible in {sup 16}O and {sup 32}S induced reactions is still an open question. Before unambiguous signals can be identified it is necessary to understand the background upon which the expected QGP signatures can be sought. An important aim of early experiments in this new energy density regime is thus to understand the process of hadronization in a nuclear environment. In any discussion of high… more

Date: January 1, 1988

Creator: Wilkes, R. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Status of the translawrencium elements (Z > 103)

As a result of conflicting claims to the discovery of the trans-lawrencium elements (Z > 103), IUPAC's Inorganic Chemistry Nomenclature Commission, (II.2), has been incapable of coming to a decision on rightful discoverer for these elements. In addition, the Atomic Weights Commission, (II.1), has from time to time been interested in the status of the search for the superheavy elements, i.e., those elements which might be found in the vicinity of the 'island of stability'. Theoretical studies ha… more

Date: January 1, 1985

Creator: Holden, Norman E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Statistical fluctuations in heavy-ion collisions

The relevance of the statistical equilibrium limit to the description of substantially relaxed degrees of freedom is discussed. Fluctuations are considered specifically in the following processes: the correlation between entrance-channel angular momentum and exit-channel kinetic energy; the sharing of the dissipated kinetic energy between the two fragments; the magnitude and the alignment of the fragment angular momentum including the effect of shell structure. It is found that statistical fluc… more

Date: February 1, 1982

Creator: Moretto, Luciano G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fractional processes and nuclear disassembly in very-heavy-ion collisions in the Fermi energy regime

Exclusive measurements of charged products and neutrons were performed for the reactions {sup 197}Au + (29 MeV/u) {sup 208}Pb and {sup 209}Bi + (28.2 MeV/u) {sup 136}Xe. The multiplicities of neutrons and charged particles are found to indicate collision impact parameters with different sensitivities. Characteristic correlations observed between massive products and light particles suggest the dominance of the damped-reaction mechanism in the Fermi energy domain. For central collisions, massive… more

Date: January 1, 1991

Creator: Schroeder, W.U.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Quark deconfinement and high energy nuclear collisions

Statistical QCD predicts that with increasing density, strongly interacting matter will undergo a transition to a plasma of deconfined quarks and gluons. High energy heavy ion collisions are expected to permit experimental studies of this transition and of the predicted new state of matter. 22 refs., 6 figs.

Date: July 1, 1986

Creator: Satz, H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Initial energy density of quark-gluon plasma in relativistic heavy-ion collisions

Recently, there has been considerable interest in the central rapidity region of highly relativistic heavy-ion collisions. Such an interest stems from the possibility of creating hadron matter of high energy density which may exceed the critical energy density for a phase transition between ordinary confined matter and the unconfined quark-gluon plasma. The experimental searches and identification of the quark-gluon plasma may provide a new insight into the question of quark confinement. The es… more

Date: January 1, 1984

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Particle production and spectra in E802 at BNL-AGS

The production of {pi}, K, and protons measured in the E802 spectrometer are studied for p+A and Si+A collisions. Systematic properties of particle spectra and rapidity density distributions are discussed in terms of centrality and reaction system. A detailed comparison of the data to the RQMD model, which employs the experimental acceptance and cuts are presented. 8 refs., 6 figs.

Date: January 1, 1991

Creator: Videbaek, F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Products from cosmic-ray interactions in extraterrestrial matter: What they tell us about radiation backgrounds in space

The nuclides and the heavy-nuclei ''tracks'' made by the interactions of solar and galactic cosmic-ray particles with meteorites, lunar samples, and the Earth have been extensively studied, simulated, and modelled. Most research involves the use of these cosmogenic products to study the history of the ''targets'' or of the cosmic rays. However, much work has also been done in understanding these interactions and in predicting their rates as a function of the target's size and shape and of the l… more

Date: January 1, 1987

Creator: Reedy, R. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Spectra of negative particles and photons in collisions of p/minus/W and /sup 16/O/minus/W at 200 GeVu

/rho//perpendicular/ spectra of negative particles were measured for p/minus/W and /sup 16/O/minus/W collisions at 200 GeVupsilon in the rapidity range 0.9< y <1.9. Within the systematic errors of 20% the spectra are indentical in the range 0.05 </rho//perpendicular/<2.0 GeVc. The p/minus/W and /sup 16/O /minus/W spectra exhibit an exponential shape for /rho//perpendicular/>250 MeVc. This is consistent with previous p/minus/A data, but there is a significant excess above this exponential at low… more

Date: January 1, 1987

Creator: Bartels, H.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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(Theoretical studies in elementary particle physics)

This report discusses research in: spin physics; transverse polarization and jet production; fundamental QCD; intermediate vector boson production; and hadron collisions. (LSP)

Date: January 1, 1991

Creator: Collins, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Studies of heavy ion reactions and transuranic nuclei. Progress report, June 1, 1976--August 31, 1977. [Summaries of research activities at University of Rochester]

Separate abstracts were prepared for the 12 papers. (JFP)

Date: August 1, 1977

Creator: Huizenga, J. R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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(Experimental physics at Yale University: Research proposal and budget Proposal, 1 January 1992--31 December 1996)

This report reviews the following topics: nuclear and quark matter; correlated pairs from heavy ion collisions-search for new low mass resonances coupled to electron-positron collisions; proposed light ion research program; experimental nuclear astrophysics (explosive nucleosynthesis); search for rare decay modes and rare processes in nuclei; and nuclear spectroscopy at the extremes of spin, isospin, and temperature. (LSP).

Date: January 1, 1992

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Nuclear chemistry research of high-energy nuclear reactions at Carnegie-Mellon University, 1961--1977. Summary report. [Summaries of research activities at Carnegie-Mellon University]

The activities and the results of research in the study of high energy nuclear reactions carried out at Carnegie Institute of Technology from 1957 to 1967 and at Carnegie-Mellon University from 1967 to 1977 are summarized. A complete list of all publications, doctoral dissertations, and reports resulting from the research of this project is also included. A major part of the report is a review of the research activities and results. The objective of the research of this project was the study of… more

Date: November 1, 1977

Creator: Caretto, A. A., Jr.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Pseudorapidity densities and fluctuations in central sup 32 S interactions at 200A GeV

Observations of heavy ion interactions at the highest available accelerator energies provide essential information for the analysis and interpretation of cosmic ray interactions. We report on an experiment in which emulsion chamber detectors were exposed to beams of 200A GeV {sup 32}S ions at the CERN SPS. We present statistical features of pseudorapidity distributions from central collisions in the experimental sample and compare them with the predictions from the Lund Model (FRITIOF) which co… more

Date: January 1, 1990

Item Type: Article

Partner: UNT Libraries Government Documents Department

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0. 9 a Gev /sup 238/U on /sup 238/U collisions in the LBL streamer chamber. Appendix A

Charged particle exclusive data for high multiplicity U on U events are reported. Analyses are based on comparison with Cugnon's intranuclear cascade model, and the explosion-evaporation simulation of Fai and Randrup. The azimuthal structure of the observed events shows evidence of collective flow. The widely used flow angle methodology proves to be relatively insensitive to collective effects under the conditions of the present experiment. An isotropic pattern of ejectile emission is not reach… more

Date: January 1, 1984

Creator: Fung, S.Y.; Beavis, D.; Gorn, W.; Keane, D.; Liu, Y.M.; Poe, R.T. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Properties of leptons

The properties of the electron, muon, tau, and their neutrinos are reviewed. Three discrepancies in our understanding of those properties are discussed: the lifetime of orthopositronium, the mass spectra of e{sup +}e{sup -} pairs produced in heavy ion collisions, and the 1-charged particle modes problem in tau decays. The review concludes with a discussion of what we need to learn about the tau and the consequent need for a tau-charm factory. 68 refs., 7 figs., 8 tabs.

Date: December 1, 1989

Creator: Perl, Martin L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Preliminary results from collisions between 3. 2-TeV /sup 16/O and target nuclei of C, Cu, and Au

We have presented preliminary WA80 data from interactions of /sup 16/O with C, Cu, and Au at 60 and 200 GeVnucleon. These have included total charged-particle multiplicity distributions and transverse energy distributions. Ranges of transverse momentum per particle and of possible energy densities were discussed. Some of the unique features of WA80 were stressed. These are: complete coverage of the target rapidity region, complete coverage of charged-particle multiplicity measurement, and measu… more

Date: January 1, 1987

Item Type: Article

Partner: UNT Libraries Government Documents Department