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18 results on '"N. C. daSilva"'

1. Directed flow of light nuclei in Au+Au collisions at 10.8AGeV/c

Author

J. R. Hall, R. Lacasse, N. Herrmann, M. W. Drigert, M. Clemen, W. C. Chang, E. O'Brien, N. C. daSilva, T. Piazza, Y. Dai, G. David, S. Bennett, Y. Kwon, R. Bersch, M. Rosati, R. Matheus, Claude Andre Pruneau, N. Xu, Peter Braun-Munzinger, J. Barrette, C. L. Woody, Johannes Peter Wessels, W. E. Cleland, R. Bellwied, Upul Sonnadara, Q. Li, O. Dietzsch, Edward L. Reber, J. Dee, S. C. Johnson, S. Sedykh, G. Wang, T. K. Hemmick, J. D. Cole, E. M. Takagui, P. Paul, M. N. Rao, D. Miśkowiec, B. Hong, S. Panitkin, K. Filimonov, T. Vongpaseuth, Johanna Stachel, J. T. Murgatroyd, S. Voloshin, Thomas Michael Cormier, S. McCorkle, M. Pollack, S. K. Mark, C. Zou, T. W. Ludlam, and Y. Zhang

Subjects
Physics, Nuclear and High Energy Physics, Light nucleus, 010308 nuclear & particles physics, Nuclear Theory, Elliptic flow, 01 natural sciences, Nuclear physics, Momentum, Deuterium, Flow (mathematics), 0103 physical sciences, Rapidity, Atomic physics, Nuclear Experiment, 010306 general physics, Anisotropy, Beam (structure)
Abstract

Directed flow of deuterons, tritons, ${}^{3}\mathrm{He},$ and ${}^{4}\mathrm{He}$ is studied in Au+Au collisions at a beam momentum of $10.8A\mathrm{GeV}/c.$ Flow of all particles is analyzed as a function of transverse momentum for different centralities of the collision. The directed flow signal, ${v}_{1}{(p}_{t}),$ is found to increase with particle mass. This mass dependence is strongest in the projectile rapidity region.

Published
1999
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2. Particle production and hydrodynamic flow: Recent results from E877 for Au+Au colliaions at AGS energy

Author

K. Filimonov, N. Starinsky, R. Matheus, Peter Braun-Munzinger, S. Voloshin, J. R. Hall, N. Herrmann, Q. Li, R. Bellwied, S. Johnson, Y. Zhang, M. W. Drigert, S. K. Mark, M. Rosati, T.K. Hemmick, B. Hong, J. Dee, S. I. Esumi, E. M. Takagui, S. Panitkin, T. W. Ludlam, S. Sedykh, Johannes Peter Wessels, P. Paul, C. L. Woody, R. Lacasse, J. D. Cole, J. Sheen, T. Vongpaseuth, J.P. Wessels, A. French, Johanna Stachel, C. Zou, J. T. Murgatroyd, W. E. Cleland, M. Trzaska, M. Clemen, Upul Sonnadara, N. Xu, Claude Andre Pruneau, Thomas Michael Cormier, W.C. Chang, N. C. daSilva, S. McCorkle, Y. Dai, Edward L. Reber, V. Pantuev, E. O'Brien, D. Miśkowiec, S. Bennett, Yujin Qi, J. Barrette, R. Bersch, T. Piazza, G. Wang, G. David, Y. Kwon, M. Pollack, and O. Dietzsch

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Hadron, Particle, Particle flow, Rapidity, Nuclear Experiment, Hydrodynamic flow
Abstract

In this article recent results of the E877 collaboration are presented. They include double differential multiplicities and rapidity densities of hadrons produced in Au+Au collisions at 11 AgeV/c, two-particle correlations of like and unlike particles, as well as some recent results on particle flow.

Published
1998
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3. Two-particle correlations in Au+Au collisions at AGS energy

Author

Q. Li, T. W. Ludlam, D. Gan, K. Filimonov, Yi Zhang, W. E. Cleland, D. Miśkowiec, O. Dietzsch, E. M. Takagui, Y. Kwon, T. Vongpaseuth, Z. Zhang, B. Hong, R. Matheus, E. O'Brien, Peter Braun-Munzinger, Upul Sonnadara, M. Clemen, M. Trzaska, S. C. Johnson, T. Piazza, N. Starinski, R. Bellwied, S. Bennett, S. Panitkin, C. Zou, Yujin Qi, W. C. Chang, A. Lukaszew, Thomas Michael Cormier, G. Wang, N. Xu, S. Voloshin, S. McCorkle, T. K. Hemmick, J. T. Murgatroyd, R. Lacasse, G. David, M. Pollack, Y. Dai, S. Gilbert, Claude Andre Pruneau, Johanna Stachel, P. Paul, J. Barrette, N. C. daSilva, C. L. Woody, C. L. Jiang, J. D. Cole, S. K. Mark, N. Herrmann, R. Bersch, M. Rosati, M. N. Rao, J. Dee, J. R. Hall, S. Sedykh, J. P. Wessels, and M. W. Drigert

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Pion, High Energy Physics::Lattice, Phase space, Nuclear Theory, Particle, High Energy Physics::Experiment, Nuclear Experiment, Energy (signal processing)
Abstract

Two-particle correlation functions have been measured in Au+Au collisions at the AGS. The one-dimensional correlations are compared to the RQMD predictions. A multidimensional analysis of two-pion correlations allows to extract the average phase space density of pions at freeze-out and the pion source velocity.

Published
1996
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4. Production of light nuclei in relativistic heavy-ion collisions

Author

W. J. Llope, G. David, Claude Andre Pruneau, F. S. Rotondo, Helio Takai, M. Muthuswamy, J. V. Germani, B. S. Kumar, J. R. Hall, K. Jayananda, S. K. Mark, G. E. Diebold, Johanna Stachel, Zhi-Yu Zhang, O. Dietzsch, N. Xu, R. D. Majka, C. Zou, D. Kraus, Thomas Michael Cormier, S. McCorkle, C. L. Woody, N. Herrmann, T. G. Throwe, J. Dee, Peter Braun-Munzinger, D. M. Wolfe, B. Hong, R. Bellwied, J. Sandweiss, S. Gilbert, N. C. daSilva, E. M. Takagui, D. Lissauer, Upul Sonnadara, T. W. Ludlam, J. T. Mitchell, Yi Zhang, R. Lacasse, J. Barrette, T. K. Hemmick, Senta Greene, E. O'Brien, and W. E. Cleland

Subjects
Coalescence (physics), Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Light nucleus, Computer Science::Information Retrieval, Nuclear Theory, Interaction volume, Nuclear physics, Nucleosynthesis, Production model, Heavy ion, Nuclear Experiment, Scaling
Abstract

We have measured cross sections for the synthesis of nuclei of mass [ital A][le]4 in collisions of 14.6[ital A] GeV/[ital c] [sup 28]Si nuclei with targets of Pb, Cu, and Al. The data are measured at close to center-of-mass rapidities, and are unique in their exploration of the centrality dependence of nucleosynthesis. Simple coalescence models that were used to study nucleosynthesis at lower energies are inadequate for the description of our measurements. Our data and improved models are used to extract parameters related to the size of the interaction volume at freeze-out.

Published
1994
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5. Evidence for expansion of a hot fireball from two-pion correlations for Si + Pb collisions at AGS energy

Author

S. K. Mark, J. V. Germani, J. Dee, M. Muthuswamy, T. W. Ludlam, G. E. Diebold, W. E. Cleland, C. L. Woody, F. S. Rotondo, T. G. Throwe, W. J. Llope, T. K. Hemmick, N. Xu, J. R. Hall, S. Panitkin, J. Barrette, R. D. Majka, D. Lissauer, R. Lacasse, O. Dietzsch, Y. Zhang, S. Gilbert, N. C. daSilva, D. Wolfe, Thomas Michael Cormier, D. Kraus, Senta Greene, S. McCorkle, E. O'Brien, J. T. Mitchell, G. Wang, Helio Takai, Claude Andre Pruneau, Z. Zhang, Johanna Stachel, G. David, C. Zou, N. Herrmann, Peter Braun-Munzinger, D. Shiva Kumar, R. Bellwied, S. Voloshin, Upul Sonnadara, M. N. Rao, B. Hong, K. Jayananda, and E. M. Takagui

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Radius, Nuclear physics, Pion, Correlation function, Cascade, Quantum interference, Experimental correlation, High Energy Physics::Experiment, Nuclear Experiment, Energy (signal processing), Boson
Abstract

The two-pion correlation function has been measured for charged pions produced in central 14.6 A GeV/ c Si + Pb collisions at the AGS. Data for like-sign pions show a clear quantum interference effect as expected for identical bosons. The experimental correlation function agrees well with that obtained for events generated by a cascade code (RQMD). The present data are consistent with a time-averaged rms freeze-out radius of 8.3 fm and a mean duration of pion emission of 9 fm/ c . The system has expanded considerably before freeze-out.

Published
1994
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6. Particle spectra and correlations from experiment 814

Author

N. Xu, T. W. Ludlam, Claude Andre Pruneau, C. Winter, R. D. Majka, Yi Zhang, Senta Greene, F. S. Rotondo, J. V. Germani, Johanna Stachel, S. K. Mark, E. O'Brien, Zhi-Yu Zhang, G. David, Rene Bellwied, W. J. Llope, S. Bennett, C. Zou, M. Muthuswamy, W. E. Cleland, D. Kraus, R. Lacasse, J. Barrette, S. Panitkin, J. Dee, Thomas Michael Cormier, C. L. Woody, N. Herrmann, S. McCorkle, Helio Takai, S. Gilbert, J. R. Hall, R. Matheus, Peter Braun-Munzinger, J. T. Mitchell, Q. Li, G. Wang, T. K. Hemmick, K. Jayananda, M. N. Rao, B. Hong, E. M. Takagui, M. Rosati, J. Stachel, Upul Sonnadara, B. Shiva Kumar, G. E. Diebold, O. Dietzsch, D. M. Wolfe, and N. C. daSilva

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, Meson, Nuclear Theory, Population, Hadron, Delta baryon, Baryon, Nuclear physics, Particle decay, Pion, Atomic physics, Nuclear Experiment, Nucleon, education
Abstract

In this article the authors summarize recent results from the E814 forward spectrometer on proton and pion distributions that give insight into the initial baryon (and energy) density achieved in central collisions as well as the temperature of the system at freeze-out. An independent measure for the latter, complementing the slope constants of particle spectra, is the population of nucleon excited states, in particular the {Delta}(1232) resonance. Besides its influence on the pion spectra it has also been identified directly in the experiment and first results are discussed. The first results from E814 on kaon spectra at low transverse momentum p{sub t} are presented; the spectra show an unexpected very steep rise at the lowest p{sub t}. The two pion correlation function has been studied for positive and negative pions and the authors show that it is consistent with a large source size at freeze-out. Finally, they show that the present data give a consistent picture of a system in thermal and chemical equilibrium at freeze-out.

Published
1994
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7. Baryon distributions in ultrarelativistic nucleus-nucleus collisions

Author

E. M. Takagui, D. Wolfe, N. Xu, R. D. Majka, N. Herrmann, B. Hong, J. T. Mitchell, W. J. Llope, W. E. Cleland, Z. Zhang, Johanna Stachel, B. Shiva Kumar, G. Wang, Senta Greene, F. S. Rotondo, J. Dee, K. Jayananda, T. K. Hemmick, Thomas Michael Cormier, E. O'Brien, J. R. Hall, S. McCorkle, M. Muthuswamy, O. Dietzsch, G. E. Diebold, Helio Takai, J. V. Germani, R. Lacasse, N. C. daSilva, D. Kraus, D. Lissauer, T. W. Ludlam, J. Barrette, Yi Zhang, C. L. Woody, C. Winter, C. Pruneau, S. Gilbert, Upul Sonnadara, M. N. Rao, T. G. Throwe, G. David, J. Sandweiss, C. Zou, Peter Braun-Munzinger, S. K. Mark, and R. Bellwied

Subjects
Physics, Particle physics, Physics and Astronomy (miscellaneous), Proton, Nuclear Theory, Resonance (particle physics), Spectral line, Baryon, Nuclear physics, medicine.anatomical_structure, Mean field theory, Thermal, medicine, Rapidity, Nuclear Experiment, Engineering (miscellaneous), Nucleus
Abstract

We have measured distributions in transverse momentum and rapidity of protons from interactions of 14.6 GeV/nucleon28Si projectiles with targets of Al and Pb. The transverse momentum spectra exhibit a thermal shape with a rapidity dependent temperature parameter. For very central or violent collisions the proton rapidity distributions exhibit the large rapidity shifts and (for Si+Al) a peak at midrapidity as required for full stopping.

Published
1993
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8. Recent results from experiment 814 at Brookhaven

Author

D. Kraus, O. Dietzsch, Upul Sonnadara, J. Dee, G. E. Diebold, S. Gilbert, N. Xu, C. Pruneau, M. Ghalambor-Dezfuli, R. Lacasse, J. R. Hall, Thomas Michael Cormier, S. K. Mark, G. Wang, B. Shiva Kumar, M.K. Fatyga, Venetios Polychronakos, T. K. Hemmick, S. McCorkle, M. Muthuswamy, G. Ingold, Johanna Stachel, L. Waters, J. V. Germani, J. T. Mitchell, D. Fox, Helio Takai, N. Herrmann, F. S. Rotondo, J. Barrette, C. L. Woody, T. G. Throwe, T. W. Ludlam, Yi Zhang, Z. Zhang, C. Winter, Senta Greene, K. Jayananda, C. Zou, W. J. Llope, E. O'Brien, W. E. Cleland, G. David, Peter Braun-Munzinger, B. Hong, J. Sandweiss, R. D. Majka, D. Lissauer, R. Bellwied, J. Simon-Gillo, N. C. daSilva, E. M. Takagui, K.L. Wolf, and D. Wolfe

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Solid angle, Spectral line, Charged particle, Nuclear physics, Transverse plane, Antiproton, Rapidity, Multiplicity (chemistry), Nuclear Experiment, Nucleon
Abstract

Recent results from the E814 collaboration are presented for reactions of 14.6 GeV/nucleon 28 Si projectiles with targets of Al, Cu, and Pb. This includes transverse energy distributions over the full solid angle and the distribution of charged particle multiplicity in the forward hemisphere. Furthermore we present recent results on transverse momentum spectra and rapidity distributions for protons and discuss them in terms of stopping and/or transparency. A fraction of nucleons emerges at beam rapidity, even for the most central collisions. These ‘punch-through’ distributions are shown to yield information on the in-medium nucleon-nucleon cross section. Finally, we discuss antiproton production at 0° as a function of event centrality to shed some light on possible reabsorption.

Published
1992
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9. Λproduction and flow in Au+Au collisions at11.5AGeV/c

Author

G. David, N. Xu, V. S. Pantuev, P. Paul, M. Pollack, J. R. Hall, R. Matheus, Peter Braun-Munzinger, O. Dietzsch, J. D. Cole, Y. Dai, M. W. Drigert, R. Bellwied, C. L. Woody, E. O'Brien, C. Zou, T. Vongpaseuth, J. Dee, Q. Li, M. Trzaska, S. Sedykh, D. Miśkowiec, Upul Sonnadara, S. C. Johnson, S. Bennett, V. Topor Pop, G. Wang, T. K. Hemmick, Claude Andre Pruneau, Thomas Michael Cormier, S. Panitkin, S. K. Mark, M. Clemen, Yujin Qi, S. McCorkle, W. E. Cleland, M. N. Rao, N. C. daSilva, Y. Kwon, Johanna Stachel, J. T. Murgatroyd, Y. Zhang, Edward L. Reber, B. Hong, J. Barrette, N. Herrmann, T. W. Ludlam, E. M. Takagui, K. Filimonov, W. C. Chang, R. Bersch, M. Rosati, Johannes Peter Wessels, T. Piazza, S. Voloshin, and R. Lacasse

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Angular distribution, Flow (mathematics), Particle flow
Published
2000
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10. Light fragment yields from central Au+Au collisions at11.5A GeV/c

Author

S. Bennett, O. Dietzsch, Yujin Qi, S. Panitkin, Claude Andre Pruneau, Johanna Stachel, J. Sheen, M. N. Rao, D. Miśkowiec, Z. Zhang, R. Matheus, Peter Braun-Munzinger, S. K. Mark, R. Bersch, M. Rosati, N. Herrmann, B. Hong, Helio Takai, C. Zou, T. Vongpaseuth, R. Bellwied, E. O'Brien, K. Filimonov, S. Voloshin, Thomas Michael Cormier, T. Piazza, C. L. Jiang, J. D. Cole, S. McCorkle, Johannes Peter Wessels, N. C. daSilva, Edward L. Reber, J. Dee, S. Sedykh, E. M. Takagui, M. Clemen, W. E. Cleland, Y. Kwon, Y. Dai, M. Pollack, W. C. Chang, T. W. Ludlam, Upul Sonnadara, C. L. Woody, R. Lacasse, S. C. Johnson, Y. Zhang, Q. Li, J. R. Hall, M. W. Drigert, T. K. Hemmick, G. David, N. Xu, and J. Barrette

Subjects
Coalescence (physics), Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Nuclear Theory, Alternating Gradient Synchrotron, 7. Clean energy, 01 natural sciences, Nuclear physics, Helium-4, Deuterium, Helium-3, 0103 physical sciences, Rapidity, Atomic physics, Impact parameter, Nuclear Experiment, 010306 general physics
Abstract

Inclusive double differential multiplicities of deuterons, {sup 3}H, {sup 3}He, and {sup 4}He measured by E877 for 11.5A GeV/c Au+Au collisions at the Brookhaven's Alternating Gradient Synchrotron (AGS) are presented. Light fragments at beam rapidity are measured for the first time at AGS energies. Beam rapidity deuteron and {sup 4}He yields and transverse slope parameters are found to be strongly dependent on the impact parameter, and the shape of the deuteron spectra is not consistent with that expected for a simple thermal distribution. The deuteron yields relative to proton yields are analyzed in terms of a simple coalescence model. While results indicate an increase in source size compared to collisions of lighter systems at the same energy, they are inconsistent with a simple coalescence model reflected by a rapidity dependence of the coalescence parameter B{sub d}. A new approach utilizing an expanding thermalized source combined with a coalescence code is developed for studying deuteron formation in heavy-ion collisions. The strong dependence of deuteron yields on collective motion implies that deuteron yields relative to those of protons can be used for constraining source parameters. (c) 2000 The American Physical Society.

Published
2000
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11. Two-proton correlations from 14.6AGeV/cSi+Pb and 11.5AGeV/cAu+Au central collisions

Author

M. Clemen, R. Lacasse, S. Voloshin, R. Matheus, S. C. Johnson, Peter Braun-Munzinger, W. C. Chang, R. Bellwied, Y. Kwon, R. Bersch, M. Rosati, D. Miśkowiec, T. W. Ludlam, Claude Andre Pruneau, Z. Zhang, J. R. Hall, E. O'Brien, Johannes Peter Wessels, T. Piazza, C. Zou, G. David, N. Xu, M. W. Drigert, M. Pollack, C. L. Woody, S. Gilbert, S. K. Mark, S. Bennett, G. Wang, T. K. Hemmick, Q. Li, T. Vongpaseuth, Edward L. Reber, J. Sheen, S. Panitkin, Y. Zhang, J. Dee, C. L. Jiang, S. Sedykh, J. D. Cole, N. C. daSilva, Thomas Michael Cormier, S. McCorkle, W. E. Cleland, N. Herrmann, Johanna Stachel, J. T. Murgatroyd, O. Dietzsch, Y. Dai, Helio Takai, V. S. Pantuev, Upul Sonnadara, J. Barrette, K. Filimonov, M. N. Rao, B. Hong, and E. M. Takagui

Subjects
Physics, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Projectile, Nuclear Theory, Transport theory, 01 natural sciences, Nuclear physics, Correlation function (statistical mechanics), 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Two-proton correlation functions have been measured in Si+Pb collisions at 14.6A GeV/c and Au+Au collisions at 11.5A GeV/c by the E814/E877 collaboration. Data are compared with predictions of the transport model RQMD and the source size is inferred from this comparison. Our analysis shows that, for both reactions, the characteristic size of the system at freeze-out exceeds the size of the projectile, suggesting that the fireball created in the collision has expanded. For Au+Au reactions, the observed centrality dependence of the two-proton correlation function implies that more central collisions lead to a larger source sizes., Comment: RevTex, 12 pages, 5 figures

Published
1999
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12. Flow in Ultrarelativistic Heavy Ion Collisions at the AGS

Author

P. Paul, T. Piazza, M. Clemen, Edward L. Reber, S. K. Mark, W. C. Chang, N. Xu, R. Lacasse, T. Vongpaseuth, S. Panitkin, Z. Zhang, M. N. Rao, Helio Takai, S. C. Johnson, N. Starinski, E. O'Brien, R. Matheus, A. French, R. Bersch, M. Rosati, M. Pollack, J. T. Murgatroyd, Claude Andre Pruneau, Peter Braun-Munzinger, G. David, B. Hong, S. Gilbert, C. Zou, Thomas Michael Cormier, M. Trzaska, N. Herrmann, Johanna Stachel, D. Miśkowiec, O. Dietzsch, R. Bellwied, K. Filimonov, S. McCorkle, S. Bennett, Yujin Qi, A. Lukaszew, J. Dee, S. Sedykh, J. D. Cole, G. Wang, T. K. Hemmick, J. Sheen, Y. Zhang, K. Jayananda, E. M. Takagui, Y. Kwon, N. C. daSilva, T. W. Ludlam, C. L. Woody, Upul Sonnadara, Q. Li, J. R. Hall, J. P. Wessels, M. W. Drigert, W. E. Cleland, Y. Dai, S. Voloshin, and J. Barrette

Subjects
Physics, Spectrometer, Plane (geometry), Nuclear Theory, Spectral line, Nuclear physics, Transverse plane, symbols.namesake, Pion, Fourier analysis, Pseudorapidity, symbols, Nuclear Experiment, Nucleon
Abstract

The azimuthal distributions of produced transverse energy from the reaction Au + Au at 10.8 AGeV/c have been studied with the nearly 4π calorimetric coverage of the E877-setup at the AGS. A Fourier analysis of these distributions has been performed in different regions of pseudorapidity as a function of centrality. The extracted sideward flow is found to be maximal in semi-central collisions. This analysis has also been employed to extract the orientation of the reaction plane. Spectra of particles identified in the forward spectrometer are then analyzed with respect to the reaction plane and their triple differential cross sections are determined. The nucleons are found to be the carriers of the sideward flow identified in the calorimeters. While the pions are also preferentially emitted into the reaction plane they show a slight tendency for emission to the opposite side of where the nucleons are found.

Published
1996
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13. Centrality dependence of longitudinal and transverse baryon distributions in ultrarelativistic nuclear collisions

Author

J. Barrette, J. V. Germani, C. Zou, G. E. Diebold, S. Gilbert, N. C. daSilva, E. M. Takagui, T. W. Ludlam, Claude Andre Pruneau, J. T. Mitchell, C. Winter, B. S. Kumar, O. Dietzsch, Upul Sonnadara, Johanna Stachel, Helio Takai, D. M. Wolfe, J. R. Hall, M. Muthuswamy, Thomas Michael Cormier, F. S. Rotondo, Nu Xu, S. McCorkle, G. Wang, T. K. Hemmick, Y. Zhang, T. G. Throwe, D. Kraus, N. Herrmann, W. E. Cleland, R. D. Majka, D. Lissauer, G. David, Senta Greene, S. K. Mark, Zhi-Yu Zhang, E. O'Brien, C. L. Woody, W. J. Llope, Peter Braun-Munzinger, R. Bellwied, K. Jayananda, M. N. Rao, J. Dee, B. Hong, and R. Lacasse

Subjects
Nuclear physics, Baryon, Physics, Nuclear reaction, Nuclear and High Energy Physics, Proton, Pseudorapidity, Hadron, Rapidity, Atomic physics, Nucleon, Charged particle
Abstract

Inclusive double differential multiplicities [ital d][sup 2][ital N]/[ital dy] d[ital p][sub [ital t]] and related quantities have been measured for protons and deuterons produced in 14.6[ital A] GeV/[ital c] Si+Al and Si+Pb collisions using the E814 forward spectrometer at the AGS at BNL. Collision centrality'' is determined by measuring [ital N][sub [ital c]], the total charged particle multiplicity in the pseudorapidity range 0.85[lt][eta][lt]3.8. For both systems Si + Al and Si + Pb, an increase in the proton rapidity distribution [ital dN]/[ital dy] at midrapidity and a corresponding decrease at higher rapidities are observed with increasing [ital N][sub [ital c]]. For Si+Pb, Boltzmann slope parameters [ital T][sub [ital B]] increase significantly in the most central collisions. The measured distributions exhibit a centrality dependence even when [sigma]/[sigma][sub geo][approx lt]10%, where full overlap between the Si and Pb nuclei occurs in a simple geometric picture. The proton rapidity distribution [ital dN]/[ital dy] is presented for the symmetric system Si+Al over the entire rapididty interval. The total number of protons, which is the integral of this quantity over rapidity, varies with [ital N][sub [ital c]]. Results are compared with various model calculations, mostly using the hadronic cascade codes ARC and RQMD. No significantmore » nuclear transparency is observed, indicating that large baryon and energy densities are produced in these collisions.« less

Published
1994

14. Observation of anisotropic event shapes and transverse flow in ultrarelativistic Au+Au collisions

Author

C. L. Jiang, M. N. Rao, Claude Andre Pruneau, T. W. Ludlam, G. David, Yi Zhang, Zixu Zhang, Y. Kwon, A. Lukaszew, T. Piazza, B. Hong, S. Voloshin, Johanna Stachel, S. Gilbert, C. Zou, R. Matheus, Peter Braun-Munzinger, N. Xu, S. K. Mark, E. O'Brien, N. C. daSilva, S. Panitkin, Upul Sonnadara, R. Bellwied, G. Wang, N. Herrmann, Helio Takai, S. Bennett, O. Dietzsch, R. Lacasse, J. Barrette, W. E. Cleland, M. Drigert, J.P. Wessels, E. M. Takagui, Thomas Michael Cormier, S. McCorkle, T. K. Hemmick, M. Rosati, J. Dee, S. Sedykh, M Clemen, C. L. Woody, Q. Li, J. R. Hall, and J. D. Cole

Subjects
Physics, Nuclear reaction, 010308 nuclear & particles physics, Computer Science::Information Retrieval, Solid angle, General Physics and Astronomy, Kinetic energy, 01 natural sciences, Nuclear physics, Transverse plane, Pseudorapidity, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Anisotropy, Event (particle physics)
Abstract

Event shapes for Au + Au collisions at 11.4 GeV/[ital c] per nucleon were studied over nearly the full solid angle with the E877 apparatus. The analysis was performed by Fourier expansion of azimuthal distributions of the transverse energy ([ital E][sub [ital T]]) measured in different pseudorapidity intervals. For semicentral collisions a pronounced event anisotropy is identified with a clear forward-backward anticorrelation. In the forward pseudorapidity interval up to 9% of the [ital E][sub [ital T]] is in a directed component. The signal decreases for peripheral and very central collisions.

Published
1994

15. Charged Particle Pseudorapidity Distributions in Au+Al, Cu, Au, and U Collisions at 10.8 A$\cdot$GeV/c

Author

J. Dee, S. Sedykh, Rene Bellwied, J. R. Hall, Sergey Voloshin, T. W. Ludlam, O. Dietzsch, S. Panitkin, Johanna Stachel, M. N. Rao, Upul Sonnadara, Y. Zhang, Y. Kwon, B. Hong, J. T. Murgatroyd, N. Xu, C. Zou, M. Rosati, J. D. Cole, T. Piazza, C. L. Woody, G. Wang, T. K. Hemmick, Claude Andre Pruneau, S. J. Bennett, A. Lukaszew, N. Starinsky, R. Matheus, Peter Braun-Munzinger, G. David, S. K. Mark, R. Lacasse, J. Barrette, J. P. Wessels, M. W. Drigert, E. O'Brien, W. E. Cleland, N. Herrmann, Thomas Michael Cormier, S. McCorkle, N. C. daSilva, E. M. Takagui, Qi Li, and M. Clemen

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Projectile, FOS: Physical sciences, Central region, Charged particle, Nuclear physics, Transverse plane, Pseudorapidity, High Energy Physics::Experiment, Multiplicity (chemistry), Nuclear Experiment (nucl-ex), Nucleon, Nuclear Experiment
Abstract

We present the results of an analysis of charged particle pseudorapidity distributions in the central region in collisions of a Au projectile with Al, Cu, Au, and U targets at an incident energy of 10.8~GeV/c per nucleon. The pseudorapidity distributions are presented as a function of transverse energy produced in the target or central pseudorapidity regions. The correlation between charged multiplicity and transverse energy measured in the central region, as well as the target and projectile regions is also presented. We give results for transverse energy per charged particle as a function of pseudorapidity and centrality., Comment: 31 pages + 12 figures (compressed and uuencoded by uufiles), LATEX, Submitted to PRC

Published
1994
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16. Compression, Expansion, and Freeze-Out in Nucleus-Nucleus Collisions at the AGS

Author

S. V. Greene, Peter Braun-Munzinger, M. Muthuswamy, M. N. Rao, E. M. Takagui, E. O’Brien, S. Panitkin, R. Majka, N. Xu, C. L. Woody, J. Barrette, T. W. Ludlam, R. Bellwied, H. Takai, W. J. Llope, F. Rotondo, C. Winter, Y. Zhang, Upul Sonnadara, J. R. Hall, D. Wolfe, J. Wessels, S. Bennett, D. Kraus, S. Sedykh, S. Gilbert, P. Braun-Munzinger, W. E. Cleland, S. K. Mark, J. T. Mitchell, K. Jayananda, G. Wang, A. Lukaszew, C. Pruneau, T. K. Hemmick, T. M. Cormier, G. E. Diebold, N. C. daSilva, B. Hong, M. Rosati, G. David, O. Dietzsch, Q. Li, J. Stachel, J. V. Germani, S. McCorkle, N. Herrmann, R. Lacasse, C. Zou, B. Shiva Kumar, J. Dee, R. Matheus, and Z. Zhang

Subjects
Physics, Particle physics, Nuclear Theory, Resonance (particle physics), Spectral line, Baryon, Nuclear physics, Strange matter, Cross section (physics), Pion, medicine.anatomical_structure, medicine, Transverse mass, Nuclear Experiment, Nucleus
Abstract

In the following we will present selected aspects of recent data on central nucleus-nucleus collisions taken by the E814/E877 collaboration at the BNL-AGS. We will first demonstrate that stopping is nearly complete in these collisions, and discuss the initial energy and baryon densities inferred from model comparisons with the data. Next we will discuss the amount of expansion the system undergoes from the initial phase until freeze-out by presenting recent results on pion-pion correlations. The (baryonic) resonance composition of the system at freeze-out is obtained by analyzing pion spectra at low transverse momentum P t and by inspection of direct measurements of the ∆(1232) resonance. Based on analysis of these measurements we will then discuss a “local” freeze-out scenario, where the freeze-out volume is connected with the temperature averaged pion-nucleon cross section. A summary of the current results and of future plans for Au-Au collisions with the E877 apparatus concludes the paper.

Published
1994
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17. Measurement of transverse energy production with Si and Au beams at relativistic energy: Towards hot and dense hadronic matter

Author

D. Kraus, J. T. Mitchell, Thomas Michael Cormier, O. Dietzsch, S. McCorkle, C. Winter, W. J. Llope, J. Simon-Gillo, M. N. Rao, C. Zou, N. Herrmann, D. Lissauer, J. V. Germani, E. M. Takagui, B. Hong, S. Bennett, W. E. Cleland, G. David, G. E. Diebold, K.L. Wolf, D. Wolfe, M. Muthuswamy, G. Wang, B. Shiva Kumar, S. Panitkin, T. K. Hemmick, T. W. Ludlam, Helio Takai, R. D. Majka, Johanna Stachel, Z. Zhang, Senta Greene, S. Gilbert, K. Jayananda, E. O'Brien, F. S. Rotondo, Nu Xu, J. R. Hall, Upul Sonnadara, J. P. Sullivan, N. C. daSilva, R. Matheus, Peter Braun-Munzinger, J. Barrette, Claude Andre Pruneau, R. Bellwied, C. L. Woody, Q. Li, T. G. Throwe, S. K. Mark, J. Dee, Yi Zhang, R. Lacasse, M. Rosati, and D. Fox

Subjects
Nuclear reaction, Physics, Nuclear physics, Transverse plane, Center-of-momentum frame, Relativistic energy, Hadron, General Physics and Astronomy, Total energy, Atomic physics, Kinetic energy, Ion
Abstract

We present a systematic study of transverse energy ([ital E][sub [ital T]]) production in collisions of 11.4[ital A] GeV/[ital c] Au and 14.6[ital A] GeV/[ital c] Si ions with targets of Al, Au, and Pb. Comparison of data for Au+Au and Si+Al indicates that, for the heavier system, there is an increase in the amount of stopping which is accompanied by a decrease in the width of the [ital dE][sub [ital T]]/[ital d][eta] distribution. The ratio of the maximum [ital E][sub [ital T]] observed for the two systems is significantly greater than the ratio of the total energy available in the center of mass frame.

Published
1993

18. Erratum: Energy and charged particle flow in 10.8AGeV/cAu+Au collisions [Phys. Rev. C55, 1420 (1997)]

Author

M. Rosati, M. N. Rao, S. Panitkin, B. Hong, N. Herrmann, Johanna Stachel, A. Lukaszew, J. R. Hall, N. C. daSilva, Y. Kwon, J. P. Wessels, Rene Bellwied, Sergey Voloshin, J. Dee, S. Sedykh, M. W. Drigert, O. Dietzsch, Thomas Michael Cormier, S. McCorkle, T. W. Ludlam, E. M. Takagui, J. T. Murgatroyd, R. Lacasse, J. D. Cole, C. Zou, Upul Sonnadara, G. Wang, T. K. Hemmick, T. Piazza, J. Barrette, W. E. Cleland, Y. Zhang, R. Matheus, Peter Braun-Munzinger, S. J. Bennett, S. K. Mark, E. O'Brien, Claude Andre Pruneau, N. Xu, Qi Li, M. Clemen, G. David, W. C. Chang, and C. L. Woody

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Flow (mathematics), 010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, 01 natural sciences, Charged particle, Energy (signal processing)
Published
1997
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