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1. Majority-vote model on random graphs

Author

Pereira, Luiz F. C. and Moreira, F. G. Brady

Subjects
Condensed Matter - Statistical Mechanics
Abstract

The majority-vote model with noise on random graphs has been studied. Monte Carlo simulations were performed to characterize the order-disorder phase transition appearing in the system. We found that the value of the critical noise parameter is an increasing function of the mean connectivity of the random graph. The critical exponents beta/nu, gamma/nu and 1/nu were calculated for several values of z, and our analysis yielded critical exponents satisfying the hyperscaling relation with effective dimensionality equal to unity., Comment: 4 pages, 6 figures

Published
2004
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3. Neutral strange particle dynamics in Au $plus$ Au collisions at AGS energies

Author

P Chung for the E895 Collaboration, J M Alexander, N N Ajitanand, M Anderson, D Best, F P Brady, T Case, W Caskey, D Cebra, J L Chance, P Chung, B Cole, K Crowe, A C Das, J E Draper, M L Gilkes, S Gushue, M Heffner, A S Hirsch, E L Hjort, L Huo, M Justice, M Kaplan, D Keane, J C Kintner, J Klay, D Krofcheck, Roy A Lacey, J Lauret, M A Lisa, H Liu, Y M Liu, R McGrath, Z Milosevich, G Odyniec, D L Olson, S Panitkin, C Pinkenburg, N T Porile, G Rai, H G Ritter, J L Romero, R Scharenberg, L Schroeder, B Srivastava, N T B Stone, T J M Symons, J Whitfield, T Wienold, R Witt, L Wood, and W N Zhang

Subjects
Physics, Nuclear and High Energy Physics, Strange quark, Space time, Gaussian, Dynamics (mechanics), Magnitude (mathematics), Scattering length, Radius, Nuclear physics, symbols.namesake, Pion, symbols, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment
Abstract

The E895 Collaboration has investigated a number of mixed-particle correlations involving neutral strange particles (K0s and Λ) in 2, 4, 6 and 8 A GeV Au + Au collisions at the AGS. The first measurements for pΛ correlations indicate a correlation magnitude of about 50% with a 26 MeV width. Detailed comparisons between data and theory suggest an emitting source with an effective Gaussian radius close to 4.5 fm. This radius is much larger than the value of 2.8 fm predicted by the relativistic transport code ART. Pairs of pK0, π−Λ and π−K0 are found to display essentially zero correlation at 6 A GeV. The latter observations are not unexpected considering that the proton–K0 interaction has a very small scattering length and there are no very well known interactions between pions and Λs or K0s.

Published
2002

4. Directed Flow ofΛHyperons in(2–6)AGeVAu+AuCollisions

Author

M. A. Lisa, S. Y. Panitkin, N. T. B. Stone, H. G. Ritter, L. S. Schroeder, D. Best, David Krofcheck, E. Hjort, T. Wienold, T. Case, D. Keane, P. Chung, N. N. Ajitanand, G. Rai, J. L. Chance, Morton Kaplan, D. Cebra, F. P. Brady, G. Odyniec, S. Gushue, J. Whitfield, Y. M. Liu, Z. Milosevich, R. Witt, M. L. Gilkes, B. K. Srivastava, T. J. M. Symons, J. L. Romero, L. Wood, Brian Cole, Matthew J. Anderson, N. T. Porile, R. P. Scharenberg, J. Lauret, R. L. McGrath, J. M. Alexander, A. C. Das, H. Liu, J. L. Klay, Roy A. Lacey, M. Heffner, A. S. Hirsch, J. E. Draper, W. N. Zhang, M. Justice, Kenneth M. Crowe, D. L. Olson, W. Caskey, J. C. Kintner, Lei Huo, and C. Pinkenburg

Subjects
Nuclear reaction, Physics, Nuclear Theory, Hadron, Hyperon, General Physics and Astronomy, Elementary particle, Lambda baryon, Lambda, Baryon, Nuclear physics, Atomic physics, Nuclear Experiment, Nucleon
Abstract

Directed flow measurements for {Lambda} hyperons are presented and compared to those for protons produced in the same Au+Au collisions (2A, 4A, and 6AGeV; b

Published
2001

5. Event-by-Event Fluctuations of the Kaon-to-Pion Ratio in CentralPb+PbCollisions at 158 GeV per Nucleon

Author

Gunther Roland, Miroslav Pikna, G. Georgopoulos, P. Seyboth, A. M. Poskanzer, Andreas Petridis, A. Billmeier, J. Sziklai, Christina Markert, G. Odyniec, R. Janik, S. Afanasiev, F. Eckhardt, H. Sann, C. O. Blyth, A. Wetzler, E. Schäfer, L. Betev, Dezso Varga, G. Igo, R. A. Barton, Daniel Ferenc, J. Gál, Siegfried Wenig, C. Höhne, J. Bartke, Helena Bialkowska, J. Zimányi, G. E. Cooper, C. A. Whitten, Fuqiang Wang, Andre Mischke, I. Szentpetery, H. Ströbele, J. Bächler, P. Foka, M. Vassiliou, Christof Roland, M. Botje, Alexander Malakhov, N. Schmitz, Dieter Røhrich, F. Pühlhofer, V. Hlinka, Tome Anticic, B. W. Mayes, J. W. Harris, Lincoln D. Carr, M. Ivanov, I. K. Yoo, Gyorgy Vesztergombi, F. P. Brady, Jozsef Molnar, G.T.A. Squier, J. M. Nelson, Thomas A. Trainor, R. Snellings, T. Ullrich, K. Kadija, J. G. Cramer, D. Barna, Rainer Arno Ernst Renfordt, Peter Strmen, Marek Gaździcki, V. Eckardt, H. G. Ritter, P. Filip, Tatjana Susa, V. I. Kolesnikov, P. Jacobs, T. A. Yates, Peter Levai, D. Vranic, Lee Stuart Barnby, P. Freund, B. Lasiuk, Z. Fodor, J. Bracinik, S. Voloshin, M. Toy, E. Skrzypczak, Ferenc Sikler, A. Sandoval, H. G. Fischer, V. Friese, D. D. Weerasundara, N. Xu, R. Bramm, Gabor Istvan Veres, Predrag Buncic, Lawrence Pinsky, B. Boimska, W. Retyk, D. Cebra, S. Margetis, S. Trentalange, Apostolos Panagiotou, M. van Leeuwen, J. Ftacnik, G. L. Melkumov, D. J. Prindle, Jeffrey G. Reid, Marek Kowalski, T. Sammer, E. Gladysz, S. Hegyi, Andrzej Rybicki, Imrich Szarka, Rene Brun, P. Csato, R. Stock, Gergely Palla, Branislav Sitar, C. Blume, Peter Graham Jones, and Thorsten Sven Kollegger

Subjects
Physics, Quantum chromodynamics, Particle physics, Meson, Nuclear Theory, Hadron, General Physics and Astronomy, Fermion, Nuclear physics, Baryon, Pion, High Energy Physics::Experiment, Nuclear Experiment, Nucleon, Event (particle physics)
Abstract

We present the first measurement of fluctuations from event to event in the production of strange particles in collisions of heavy nuclei. The ratio of charged kaons to charged pions is determined for individual central Pb+Pb collisions. After accounting for the fluctuations due to detector resolution and finite number statistics we derive an upper limit on genuine nonstatistical fluctuations, which could be related to a first- or second-order QCD phase transition. Such fluctuations are shown to be very small.

Published
2001

6. Λ flow and Λ-P correlation in Au + Au collisions at AGS energies

Author

C. Law, A. S. Hirsch, J. Whitfield, F. P. Brady, G. Odyniec, N. N. Ajitanand, J. E. Draper, K.M. Crowe, Lei Huo, W. N. Zhang, J. Lauret, N T B Stone, James Alexander, M. L. Gilkes, L. Wood, H. G. Ritter, Brian Cole, Matthew J. Anderson, J L Chance, M. Heffner, R. P. Scharenberg, A. C. Das, Y. M. Liu, H. Liu, Morton Kaplan, S. Y. Panitkin, Roy A. Lacey, C. Pinkenburg, S Gushue, T. J. M. Symons, E. L. Hjort, M. A. Lisa, M. Justice, D. Cebra, D. L. Olson, W. Caskey, Z. Milosevich, J. C. Kintner, R. Witt, L. S. Schroeder, B. K. Srivastava, D. Keane, P. Chung, G. Rai, T. Case, J. Klay, D. Best, J. L. Romero, David Krofcheck, N. T. Porile, and R. L. McGrath

Subjects
Quark, Physics, Nuclear and High Energy Physics, Scattering, Nuclear Theory, Hyperon, Magnitude (mathematics), Nuclear physics, Flow ratio, Transverse plane, Flow (mathematics), Atomic physics, Nuclear Experiment, Beam (structure)
Abstract

Transverse and radial flow measurements are presented for Λ hyperons along with Λ-P correlations from Au + Au collisions at AGS energies. The flow measurements are compared with those of co-produced protons. The measurements indicate that Λ hyperons flow consistently in the same direction as protons but with a smaller magnitude for all beam energies. Comparisons with RQMD calculations show that the experimentally determined Λ sideward flow is consistently larger compared with the calculated value obtained from scattering processes only. The experimental transverse flow ratio Λ/P is consistent with predictions ( 2/3) of the quark counting rule at 2 A GeV but is found to decrease with increasing beam energy. These observations may be related to the detailed features of the Λ-nucleon potential for the nuclear densities produced. At 6 A GeV, Λp correlation functions are observed to be essentially flat (within statistical uncertainty), indicating little or no correlation between Λs and co-produced protons. This suggests that Λs may have a spacetime emission pattern which is different from that for protons. Further evidence from radial flow measurements also indicates that 6 A GeV Λ hyperons (at mid-rapidity) do not share the same emitting source characteristics as co-produced protons.

Published
2001

7. Correlations and fluctuations in Pb+Pb collisons

Author

V. Eckardt, Z. Fodor, G. Odyniec, H. G. Fischer, Siegfried Wenig, R. A. Barton, Juraj Bracinik, Alexander Malakhov, P. Seyboth, Jozsef Molnar, Branislav Sitar, Gyorgy Vesztergombi, G.T.A. Squier, Imrich Szarka, C. O. Blyth, Lincoln D. Carr, Christoph Blume, D. D. Weerasundara, A. M. Poskanzer, J. G. Cramer, Panagiota Foka, Andrzej Rybicki, T. Susa, P. Freund, L. S. Pinsky, Marek Gaździcki, S. Margetis, H. Sann, J. Grebieszkow, F. Pühlhofer, Jeffrey G. Reid, H. G. Ritter, K. Kadija, C. Höhne, Bożena Boimska, Rene Brun, Peter Levai, J. Ftacnik, F. P. Brady, J. Zimányi, D. Cebra, J. Sziklai, Apostolos Panagiotou, I. K. Yoo, N. Schmitz, Dieter Røhrich, Peter Graham Jones, G. L. Melkumov, S. Voloshin, M. Toy, J. M. Nelson, G.E. Cooper, J. Bartke, J. Bächler, M. Vassiliou, G. Pálla, Peter Strmen, L. Betev, D. J. Prindle, C. P. A. Roland, E. Schäfer, V. Hlinka, A. Yu. Semenov, Marek Kowalski, T. Ullrich, T. Sammer, H. Ströbele, E. Gladysz, B. W. Mayes, A. Billmeier, S. Trentalange, P. Csato, Peter Martin Jacobs, R. Stock, Predrag Buncic, R. Janik, Andreas Petridis, D. Barna, D. Varga, F. Eckhardt, V. I. Kolesnikov, A. Sandoval, T. A. Yates, Gabor Istvan Veres, E. Skrzypczak, S. Hegyi, G. Igo, M. Oldenburg, Helena Bialkowska, Rainer Arno Ernst Renfordt, W. Retyk, R.J.M. Snellings, D. Vranic, N. Xu, Gunther Roland, B. Lasiuk, Christina Markert, C. A. Whitten, Ferenc Sikler, R. Ganz, M. V. Ivanov, V. Friese, Miroslav Pikna, I. Szentpetery, Lee Stuart Barnby, R. Lednicky, Thomas A. Trainor, J. Gál, Daniel Ferenc, Fuqiang Wang, and J. W. Harris

Subjects
Nuclear physics, Physics, Nuclear reaction, Nuclear and High Energy Physics, Strange matter, Deuterium, Nuclear Experiment, Anisotropy, Deconfinement, Event (particle physics), Atomic and Molecular Physics, and Optics, Charged particle, NA49 experiment
Abstract

Results on two-particle correlations, deuteron production, event anisotropy and event-by-event fluctuations of 〈 p T 〉 and K/π were obtained by the NA49 experiment in Pb+Pb collisions at 158 A·GeV beam energy. The interpretation of the measurements is discussed in light of the search for deconfinement.

Published
2001

8. Elliptic Flow inAu+AuCollisions at√sNN=130GeV

Author

N. Stone, Christophe Pierre Suire, A. Lebedev, B. Miller, M. M. de Moura, M. Dialinas, P. Middlekamp, J. Scheblien, V. Ghazikhanian, A. Etkin, A. H. Tang, A. P. Meschanin, R.Kh. Kutuev, J. Berger, J. L. Romero, V. Fine, J. Engelage, T. J. Humanic, Peter J. Lindstrom, D. Zimmerman, I.A. Savin, N. T. Porile, Yu A. Matulenko, M. Horsley, Thomas LeCompte, B. Stringfellow, J. Sedlmeir, L. Smykov, E. Finch, T. S. McShane, J. W. Harris, Joakim Nystrand, V. B. Dunin, J. Grabski, P. Seyboth, D. Dayton, C. J. Liaw, R. Bossingham, J. N. Marx, C. Drancourt, S. Tonse, W. S. Deng, J. G. Cramer, R. A. Scheetz, A. Stolpovsky, H. Hümmler, L. Kotchenda, G. Koehler, E. Gushin, G. J. Kunde, P. Yepes, V. Eckardt, M. Kramer, A. I. Pavlinov, Y. Panebratsev, D. Grosnick, Granville Ott, G. Eppley, A. V. Brandin, V. Trofimov, J. M. Landgraf, M. Strikhanov, K. Krueger, M. B. Tonjes, E. I. Shakaliev, A. Yokosawa, Jinghui Yang, E. Sugarbaker, J. Hunter, H. Z. Huang, V. Morozov, A. Tarchini, S. V. Razin, K. Wilson, G. Rai, Y. Shi, G. Van Buren, J. M. Nelson, P. A. DeYoung, J. Pluta, C. Roy, H. Stroebele, J. Carroll, C. Byrd, N. Xu, G. D. Westfall, D. Padrazo, R. Wells, C. Struck, W. Pinganaud, D. Hardtke, F. Laue, J.F. Amsbaugh, Jay Roberts, N. Adams, David Fritz, J. Sandweiss, G. LoCurto, A. C. Saulys, S. R. Klein, C. E. Allgower, R. D. Majka, J. Zhu, Sergey Voloshin, J. Sowinski, Matthew Nguyen, W. Peryt, J. Takahashi, J. Wolf, C. Feliciano, Y. Fisyak, L. Greiner, K. J. Foley, J. Schambach, E. L. Hjort, S. Pirogov, A. Ogawa, Ian Johnson, Krista M. Marks, S. E. Vigdor, Vladimir Petrov, C. L. Kunz, Z. Li, O. Barannikova, D. L. Olson, F. P. Brady, Gerald W Hoffmann, S. P. Chernenko, D. Seliverstov, A. Schüttauf, Christian Claude Kuhn, W. J. Llope, Q. Li, C. O. Blyth, C. F. Moore, M. Cherney, H. Fessler, W. Christie, Thomas Michael Cormier, D.E. Greiner, T. Krupien, Torre Wenaus, Masashi Kaneta, Ross Schlueter, W. M. Zhang, Andrey Vasiliev, D. Hill, Richard C. Jared, M. Calderón de la Barca Sánchez, R. Weidenbach, T. Nguyen, A. Cardenas, Peter Martin Jacobs, N. Schmitz, S. Chatopadhyay, P. Nevski, M. Lopez-Noriega, A. Klyachko, R. Witt, E. Yamamoto, J. Klay, Thomas A. Trainor, W. R. Edwards, P. Sappenfield, N.D. Gagunashvili, J. Baudot, E. A. Matyushevski, P. Kuczewski, J. C. Dunlop, A. A. Derevschikov, K. Olchanski, V. I. Danilov, C. P. Lansdell, Wilfred J. Braithwaite, E. Mogavero, R.J.M. Snellings, Janet Elizabeth Seger, J. Lin, M. A. C. Lamont, S. B. Nurushev, Z. Milosevich, B. Lasiuk, J. Wisdom, Y. V. Zanevski, F. Retiere, W. Hunt, V. Kormilitsyne, D. Russ, B. E. Bonner, J. T.M. Chrin, G. S. Mutchler, H. Diaz, J. R. Hall, Zubayer Ahammed, G. A. Ososkov, M. J. LeVine, B. Norman, J. Gross, H. Long, K. Bradley, Yu Chen, Wen-Chang Chen, N. G. Minaev, O. D. Tsai, R. P. Scharenberg, Marie Germain, R. Seymour, M. A. Howe, B. Choi, R. Marstaller, W. Betts, Vladimir Tikhomirov, Salahuddin Ahmad, I. Polk, H. S. Matis, G. C. Harper, A. S. Hirsch, P. Kravtsov, A. Maliszewski, Alexander Kovalenko, L. V. Nogach, L. C. Bland, S. Bennett, H. J. Crawford, I. Vakula, C. Adler, F. S. Bieser, L. Wood, A. N. Zubarev, C. A. Ogilvie, G. Brugalette, V. S. Shvetcov, L. S. Schroeder, J. Meier, H. Liu, S. U. Pandey, A. E. Yakutin, I. Flores, Morton Kaplan, V. Perevotchikov, C. A. Whitten, M. Pentia, Marek Gazdzicki, L. Lakehal-Ayat, D. Lopiano, S. Trentalange, A. Ridiger, W. W. Jacobs, M. I. Ferguson, J. Lamas-Valverde, C. Gojak, M. Botlo, Guy Paic, I. Sakrejda, T. Ngo, E. Platner, B. Minor, V. Lindenstruth, V. A. Nikitin, S. Heppelmann, D. Flierl, Ma Bloomer, John Z. H. Zhang, A. Chikanian, S. S. Shimanskii, J. Mitchell, E. G. Judd, L. Martin, Jeffrey G. Reid, B. K. Srivastava, I. M. Vasilevski, K. E. Shestermanov, V. V. Belaga, Lincoln D. Carr, J. Gans, S. Lange, L. Arnold, Boris Hippolyte, G. Skoro, M. Heffner, J. E. Draper, J. Puskar-Pasewicz, R. Morse, V. Grigoriev, J. P. Coffin, O. V. Rogachevski, N. Bouillo, M. DeMello, S. J. Lindenbaum, N. Mikhalin, A. Boucham, H. Ward, M. Oldenburg, Peter Graham Jones, R. L. Ray, V. Emelianov, D. Keane, A. R. Baldwin, A. A. P. Suaide, L. Didenko, Damien Bonnet, Nikolai Smirnov, R. Stock, S. Y. Panitkin, E. Potrebenikova, W. J. Leonhardt, S. Bekele, S. Bouvier, V. P. Kenney, L. G. Efimov, Frank Jm Geurts, Yu. Ivanshin, J. Castillo, S. W. Wissink, R. L. Brown, W. Dominik, P. Jensen, A. Ishihara, T. Ljubicic, Alexander Khodinov, Robert Stone, M. Tokarev, G. Guilloux, Robert R. J. Maier, D. DiMassimo, E. Anderssen, A. M. VanderMolen, H. H. Wieman, H. Caines, S. Jacobson, D. Shuman, R. Willson, D. G. Underwood, J. Wirth, D. Reichhold, T. J. Hallman, T. J. M. Symons, K. Turner, A. Szanto de Toledo, A. M. Poskanzer, J. Tarzian, P. He, K. Solberg, T. Pawlak, A. Vanyashin, Z. Sandler, B. Caylor, R. S. Longacre, V. L. Rykov, J. Porter, G. Igo, J. Seyboth, P. Fachini, D. D. Weerasundara, Mingshui Chen, M. Grau, S. Margetis, O. A. Grachov, M. Schulz, J. R. Lutz, Rainer Arno Ernst Renfordt, J. Balewski, H. G. Ritter, Claude Andre Pruneau, H. Arnesen, R. Zoulkarneev, R. Bellwied, A. S. Konstantinov, K. H. Ackermann, D. M. Moltz, A. A. Kuznetsov, Ivan Kotov, T. Noggle, V. M. Leontiev, Olivier Ravel, J. Whitfield, T. Ullrich, D. Roehrich, B. Erazmus, Z. Z. Xu, D. Cebra, C. Consiglio, M. Beddo, Yu Melnick, P. Leszczynski, J. Bercovitz, T. Herston, J. Riso, Lee Stuart Barnby, V. A. Moiseenko, Marcelo Gameiro Munhoz, D. J. Prindle, E. J. Stephenson, M. A. Lisa, W. A. Love, T. Nussbaum, Daniel Ferenc, Fuqiang Wang, H. Bichsel, G. Odyniec, V. I. Yurevich, E. S. Braithwaite, J. Boehm, T. Eggert, David Lynn, L. Madansky, R. Sanchez, J. Dioguardi, J. H. Thomas, L. Conin, G. Visser, G. S. Averichev, C. P. McParland, H. M. Spinka, J. Rasson, Chinh Vu, and Matthew J. Anderson

Subjects
Physics, Particle physics, Time projection chamber, Hadron, Elliptic flow, General Physics and Astronomy, Observable, Particle accelerator, Charged particle, law.invention, Nuclear physics, law, Pseudorapidity, Nuclear Experiment, Relativistic Heavy Ion Collider
Abstract

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at √(sNN) = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v₂, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

Published
2001

9. Production of φ-mesons in p+p, p+Pb and central Pb+Pb collisions at GeV

Author

D. J. Prindle, Marek Kowalski, T. Sammer, E. Gladysz, J. Gál, H. G. Fischer, F. Pühlhofer, Lawrence Pinsky, Christoph Blume, L. Betev, Andrzej Rybicki, J. M. Nelson, Gyorgy Vesztergombi, Daniel Ferenc, Fuqiang Wang, Tatjana Susa, R. Ganz, Rene Brun, Norbert Schmitz, P. Seyboth, J. W. Harris, Kreso Kadija, B. W. Mayes, V. Eckardt, Miroslav Pikna, C. O. Blyth, S. Voloshin, S. Afanasiev, N. Xu, P. Freund, Lee Stuart Barnby, F. Eckhardt, Rainer Arno Ernst Renfordt, Peter Martin Jacobs, Peter Graham Jones, Marian Ivanov, H. G. Ritter, Predrag Buncic, J. G. Cramer, Lincoln D. Carr, D. Cebra, Peter Levai, S. Trentalange, Apostolos Panagiotou, Dieter Røhrich, G. Odyniec, Marek Gaździcki, G. Igo, M. Oldenburg, Andreas Petridis, R. Janik, V. I. Kolesnikov, G. L. Melkumov, C. P. A. Roland, T. A. Yates, E. Skrzypczak, G. Pálla, J. Grebieszkow, Dezso Varga, Jozsef Molnar, G.T.A. Squier, D. Vranic, S. Margetis, T. Ullrich, D. Barna, R. A. Barton, A. Sandoval, E. Schäfer, A. Yu. Semenov, A. Billmeier, S. Hegyi, G.E. Cooper, I. Szentpetery, Ferenc Sikler, R.J.M. Snellings, Peter Strmen, A. M. Poskanzer, F. P. Brady, Helena Bialkowska, Andre Mischke, Branislav Sitar, D. D. Weerasundara, B. Boimska, J. Sziklai, J. Ftacnik, Panagiota Foka, Christina Markert, P. Csato, R. Stock, V. Friese, C. Höhne, C. A. Whitten, Thomas A. Trainor, Juraj Bracinik, Gunther Roland, Imrich Szarka, M. Toy, Alexander Malakhov, J. Bächler, M. Vassiliou, Jeffrey G. Reid, V. Hlinka, Tome Anticic, J. Zimányi, Gabor Istvan Veres, Siegfried Wenig, W. Retyk, B. Lasiuk, Z. Fodor, H. Sann, I. K. Yoo, J. Bartke, and H. Ströbele

Subjects
Physics, Nuclear and High Energy Physics, Minimum bias, Meson, Analytical chemistry, Electron beam processing, Yield ratio, Atomic physics, Multiplicity (chemistry), Phi meson
Abstract

Yields and phase space distributions of φ -mesons emitted from p+p (minimum bias trigger), p+Pb (at various centralities) and central Pb+Pb collisions are reported ( E beam =158 A GeV). The decay φ →K + K − was used for identification. The φ / π ratio is found to increase by a factor of 3.0±0.7 from inelastic p+p to central Pb+Pb. Significant enhancement in this ratio is also observed in subclasses of p+p events (characterized by high charged-particle multiplicity) as well as in the forward hemisphere of central p+Pb collisions. In Pb+Pb no shift or significant broadening of the φ -peak is seen.

Published
2000

10. Antiflow ofKs0Mesons in6AGeVAu+AuCollisions

Author

James Alexander, E. Hjort, A. S. Hirsch, T. Case, H. G. Ritter, F. P. Brady, G. Odyniec, J. L. Romero, N. T. Porile, M. A. Lisa, Kenneth M. Crowe, H. Liu, N. T. B. Stone, Brian Cole, Matthew J. Anderson, L. S. Schroeder, R. L. McGrath, R. P. Scharenberg, R. Witt, A. C. Das, W. N. Zhang, N. N. Ajitanand, B. K. Srivastava, J. Lauret, J. L. Klay, Roy A. Lacey, M. Justice, M. Heffner, Lei Huo, S. Gushue, M. L. Gilkes, J. Whitfield, T. Wienold, S. Y. Panitkin, C. Pinkenburg, Morton Kaplan, L. Wood, J. L. Chance, D. Cebra, J. E. Draper, Z. Milosevich, D. L. Olson, W. Caskey, Y. M. Liu, T. J. M. Symons, G. Rai, D. Keane, P. Chung, D. Best, David Krofcheck, and J. C. Kintner

Subjects
Nuclear reaction, Physics, Range (particle radiation), Meson, 010308 nuclear & particles physics, Hadron, General Physics and Astronomy, Elementary particle, Nuclear matter, 01 natural sciences, Nuclear physics, 0103 physical sciences, Impact parameter, 010306 general physics, Boson
Abstract

We have measured the sideward flow of neutral strange (K{sup 0}{sub s} ) mesons in 6A GeV Au +Au collisions. A prominent antiflow signal is observed for an impact parameter range (b(less-or-similar sign)7 fm ) which spans central and midcentral events. Since the K{sup 0}{sub s} scattering cross section is relatively small in nuclear matter, this observation suggests that the in-medium kaon vector potential plays an important role in high density nuclear matter. (c) 2000 The American Physical Society.

Published
2000

11. Deuteron production in central Pb+Pb collisions at 158A GeV

Author

P. Freund, G. Roland, Gyorgy Vesztergombi, R. Snellings, E. Schäfer, H. G. Ritter, Siegfried Wenig, S. Afanasiev, F. Eckhardt, Rainer Arno Ernst Renfordt, D. Cebra, S. Trentalange, Apostolos Panagiotou, Andrzej Rybicki, Andreas Petridis, L. Betev, P. Jacobs, Peter Levai, J. G. Cramer, J. Zimányi, Dezso Varga, G. Igo, M. Oldenburg, J. W. Harris, C. O. Blyth, Ferenc Sikler, Dieter Røhrich, I. Szentpetery, G. L. Melkumov, Rene Brun, P. Strmen, F. P. Brady, Daniel Ferenc, Fuqiang Wang, M. Vassiliou, Andre Mischke, C. Roland, Marek Gaździcki, V. Hlinka, R. A. Barton, C. Blume, A. Semenov, Tome Anticic, N. Xu, Zoltan Fodor, D. J. Prindle, Jozsef Molnar, P. Seyboth, V. Friese, G.T.A. Squier, Norbert Schmitz, V. Eckardt, D. D. Weerasundara, T. Ullrich, J. Bächler, Marek Kowalski, S. Margetis, T. Sammer, B. Boimska, Lee Stuart Barnby, E. Gladysz, Kreso Kadija, I. K. Yoo, R. Ganz, S. Hegyi, J. Sziklai, B. Sitar, S. Voloshin, A. M. Poskanzer, Peter Graham Jones, B. W. Mayes, H. G. Fischer, P. Csato, A. Sandoval, M. Pikna, R. Janik, A. Billmeier, J. Bracinik, Lawrence Pinsky, Christina Markert, G. Odyniec, E. Skrzypczak, R. Stock, J. Grebieszkow, F. Pühlhofer, M. Ivanov, J. M. Nelson, V. I. Kolesnikov, Lincoln D. Carr, T. A. Yates, D. Vranic, D. Barna, Helena Bialkowska, Gergely Palla, J. Ftáčnik, Thomas A. Trainor, I. Szarka, C. Höhne, G. E. Cooper, C. A. Whitten, Jeffrey G. Reid, J. Gál, P. Bunčić, H. Ströbele, P. Foka, C. Struck, H. Sann, M. Toy, J. Bartke, Alexander Malakhov, Gabor Istvan Veres, W. Retyk, B. Lasiuk, and Tatjana Susa

Subjects
Coalescence (physics), Physics, Nuclear and High Energy Physics, Large Hadron Collider, Astrophysics::High Energy Astrophysical Phenomena, High Energy Physics::Phenomenology, Inverse, Exponential function, Nuclear physics, Pion, Deuterium, Electron beam processing, Transverse mass, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment
Abstract

Experimental results on deuteron emission from central Pb+Pb collisions ( E beam =158A GeV, fixed target), obtained by NA49 at the CERN SPS accelerator, are presented. The transverse mass m t distribution was measured near mid-rapidity (2.0 y m t − m 0 c 2 (0 p t c ) for the 4% most central collisions. An exponential fit gives an inverse slope T d =(450±30) MeV and a yield dN d / dy =0.34±0.03. The coalescence factor B 2 ( m t = m 0 )=(3.5±1.0)·10 −4 GeV 2 and its m t -dependence are determined and discussed in terms of a model that includes the collective expansion of the source created in a collision. The derived Gaussian size parameter R G of the emission volume is consistent with earlier HBT results on the source of pion emission.

Published
2000

12. Sideward Flow inAu+AuCollisions between2Aand8AGeV

Author

H. Liu, N. N. Ajitanand, J. Alexander, M. Anderson, D. Best, F. P. Brady, T. Case, W. Caskey, D. Cebra, J. Chance, B. Cole, K. Crowe, A. Das, J. Draper, M. Gilkes, S. Gushue, M. Heffner, A. Hirsch, E. Hjort, L. Huo, M. Justice, M. Kaplan, D. Keane, J. Kintner, J. Klay, D. Krofcheck, R. Lacey, M. A. Lisa, Y. M. Liu, R. McGrath, Z. Milosevich, G. Odyniec, D. Olson, S. Y. Panitkin, N. Porile, G. Rai, H. G. Ritter, J. Romero, R. Scharenberg, L. S. Schroeder, B. Srivastava, N. T. B. Stone, T. J. M. Symons, S. Wang, J. Whitfield, T. Wienold, R. Witt, L. Wood, X. Yang, W. N. Zhang, and Y. Zhang

Subjects
Physics, Azimuth, Nuclear physics, Range (particle radiation), Time projection chamber, Flow (mathematics), Orientation (geometry), General Physics and Astronomy, Nuclear Experiment, Anisotropy, Fourier series, Beam (structure)
Abstract

Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au+Au collisions at beam energies of 2A, 4A, 6A, and 8A GeV are presented in the form of in-plane transverse momentum and the first Fourier coefficient of azimuthal anisotropy v(1). These measurements indicate a smooth variation of sideward flow as a function of beam energy. The data are compared with four nuclear transport models which have an orientation towards this energy range. All four exhibit some qualitative trends similar to those found in the data, although none show a consistent pattern of agreement within experimental uncertainties.

Published
2000

13. Bombarding Energy Dependence ofπ−Interferometry at the Brookhaven AGS

Author

G. Odyniec, S. Gushue, E. Hjort, D. Best, T. Case, W. N. Zhang, T. J. M. Symons, J. L. Romero, H. G. Ritter, R. P. Scharenberg, David Krofcheck, Y. M. Liu, J. L. Chance, Kenneth M. Crowe, M. L. Gilkes, D. Cebra, A. C. Das, H. Liu, Brian Cole, Matthew J. Anderson, J. L. Klay, Roy A. Lacey, F. P. Brady, J. E. Draper, M. Heffner, J. Whitfield, D. Keane, P. Chung, A. S. Hirsch, J. Lauret, N. N. Ajitanand, M. A. Lisa, J. C. Kintner, G. Rai, S. Y. Panitkin, Russell Wells, J. M. Alexander, R. Witt, L. Wood, B. K. Srivastava, D. L. Olson, W. Caskey, N. T. B. Stone, M. Justice, N. T. Porile, R. L. McGrath, L. S. Schroeder, Lei Huo, C. Pinkenburg, Z. Milosevich, T. Wienold, and Morton Kaplan

Subjects
Physics, Nuclear physics, Excitation function, Mean field theory, Reaction dynamics, General Physics and Astronomy, Alternating Gradient Synchrotron, Sensitivity (control systems), Atomic physics, Nuclear Experiment, Nuclear matter, Intensity (heat transfer), Energy (signal processing)
Abstract

We present the first excitation function of ${\ensuremath{\pi}}^{\ensuremath{-}}$ intensity interferometry at Alternating Gradient Synchrotron (AGS) energies (2--8 A GeV). The sensitivity of the multidimensional correlation functions to the geometry and dynamics of the pion-emitting system provides a stringent test of transport models of heavy ion collisions. Detailed comparisons with a realistic transport model, both with and without an explicit nuclear mean field, suggest that the beam energy evolution in the reaction dynamics is different in the model than in the data. A significantly increased ${\ensuremath{\pi}}^{\ensuremath{-}}$ emission time scale, which has been suggested as a signal of the onset of the transition to quark-gluon plasma, is not observed.

Published
2000

14. Results from the experiment E895 at the BNL AGS

Author

N. T. Porile, M. A. Lisa, P. Chung, J. L. Romero, S. Y. Panitkin, D. Keane, N T B Stone, Y. M. Liu, G. Rai, Yufeng Zhang, S. Gushue, K. Crowe, R. P. Scharenberg, N.N. Ajitanand, T. Case, J. Klay, Brian Cole, G. Odyniec, D. Best, D. L. Olson, R. L. McGrath, T. Wienold, Morton Kaplan, J. L. Chance, R. Lacey, David Krofcheck, M. Heffner, D. Cebra, J. C. Kintner, C. Pinkenburg, J. Whitfield, L. Wood, W. Caskey, Z. Milosevich, James Alexander, T. J. M. Symons, E. L. Hjort, X. Yang, L. S. Schroeder, Andrew S. Hirsch, M. Anderson, R. Witt, M. Justice, W. N. Zhang, M.L. Gilkes, Hans Georg Ritter, S. Wang, F. P. Brady, B. K. Srivastava, L. Huo, R. Wells, A. C. Das, H. Liu, and J. E. Draper

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Time projection chamber, Physics::Instrumentation and Detectors, Detector, Observable, Context (language use), Particle identification, Nuclear physics, Nuclear Experiment, Event (particle physics), Beam (structure), Excitation
Abstract

We present some of the latest results from the E895 experiment conducted at the BNL AGS accelerator. Au+Au collisions were recorded by the EOS Time Projection Chamber (TPC) at beam energies of 2, 4, 6, and 8 A GeV. The TPC detector permitted the reconstruction of individual collision events with almost 4π acceptance and good particle identification. This capability allowed E895 to study global observables and two particle correlations with respect to symmetries of the event. Flow excitation functions are examined and discussed in the context of the Nuclear Equation of State.

Published
1999

15. Elliptic Flow: Transition from Out-of-Plane to In-Plane Emission inAu+AuCollisions

Author

M. L. Gilkes, Wei Zhang, R. Witt, D. Keane, P. Chung, J. Lauret, James Alexander, J. Whitfield, J. L. Chance, S. Y. Panitkin, D. Cebra, N. T. Porile, K. Crowe, R. L. McGrath, Pol Bernard Gossiaux, Pawel Danielewicz, J. C. Kintner, H. G. Ritter, M. Heffner, W. Caskey, L. S. Schroeder, J. L. Romero, G. Rai, A. C. Das, R. P. Scharenberg, H. Liu, M. A. Lisa, Roy A. Lacey, J. Klay, D. Best, N T B Stone, Brian Cole, D. L. Olson, G. Odyniec, C. Law, E. L. Hjort, L. Wood, F. P. Brady, S. Gushue, C. Pinkenburg, T. Case, J. E. Draper, David Krofcheck, M. Justice, Y. M. Liu, T. J. M. Symons, M. Anderson, B. K. Srivastava, L. Huo, Andrew S. Hirsch, N. N. Ajitanand, A. Elmaani, Z. Milosevich, T. Wienold, and Morton Kaplan

Subjects
Physics, Excitation function, Range (particle radiation), Proton, 010308 nuclear & particles physics, Nuclear Theory, Elliptic flow, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Boltzmann equation, Out of plane, Nuclear physics, Baryon, 0103 physical sciences, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract

We have measured the proton elliptic flow excitation function for the Au + Au system spanning the beam energy range 2 -- 8 AGeV. The excitation function shows a transition from negative to positive elliptic flow at a beam energy, $E_{tr} \sim$ 4 AGeV. Detailed comparisons with calculations from a relativistic Boltzmann-equation are presented. The comparisons suggest a softening of the nuclear equation of state (EOS) from a stiff form (K \sim 380 MeV) at low beam energies (E_{Beam} \le 2 AGeV) to a softer form (K \sim 210 MeV) at higher energies (E_{Beam} \ge $ 4 AGeV) where the calculated baryon density $ \rho \sim 4 \rho_0$.

Published
1999

16. Baryon Stopping and Charged Particle Distributions in CentralPb+PbCollisions at 158 GeV per Nucleon

Author

C. Roland, Rainer Arno Ernst Renfordt, S. Margetis, A. Piper, N. Xu, Andrzej Rybicki, Jeffrey G. Reid, H. Ströbele, C. A. Whitten, Rene Brun, C. Bormann, P. Foka, R. Brockmann, R. Ganz, H. Hümmler, Ferenc Sikler, Lee Stuart Barnby, H. L. Caines, Norbert Schmitz, D. D. Weerasundara, Peter Graham Jones, Andreas Petridis, J. Sziklai, T. Ullrich, V. Friese, D. Schmischke, B. Boimska, E. Schäfer, Helena Bialkowska, F. Eckhardt, J. Gál, A. Yu. Semenov, J. Bächler, S. Hegyi, G. L. Melkumov, C. O. Blyth, W. Retyk, S. Schönfelder, Gyorgy Vesztergombi, M. Vassiliou, W. Geist, M. Fuchs, G. Roland, Siegfried Wenig, L. Wood, R. Zybert, A. Sandoval, R.J. Porter, Thomas A. Trainor, Alexander Malakhov, H. Appelshäuser, H. G. Fischer, G. Igo, M. Oldenburg, J. Dunn, D. Irmscher, H. Sann, S. Poziombka, D. Cebra, J. Günther, S. Trentalange, M. I. Ferguson, A. M. Poskanzer, Apostolos Panagiotou, S. J. Bailey, T. Wienold, X. Z. Zhu, A. Billmeier, Peter Levai, J. Zimányi, Christina Markert, G. Odyniec, I. Huang, A. Mock, D. J. Prindle, Torsten Henkel, J. Grebieszkow, B. Lasiuk, P. Freund, Marek Kowalski, H. Rudolph, E. Gladysz, P. Seyboth, J. Bartke, J. W. Harris, H. G. Ritter, V. I. Kolesnikov, P. Jacobs, V. Eckardt, T. A. Yates, F. P. Brady, D. Vranic, R. A. Barton, Fuqiang Wang, L. A. Hill, G. E. Cooper, M. Toy, D. Flierl, J. G. Cramer, E. Skrzypczak, I. Szentpetery, Marek Gaździcki, Zoltan Fodor, F. Pühlhofer, J. M. Nelson, Dieter Røhrich, Jozsef Molnar, R. Bock, G.T.A. Squier, K. Kadija, Predrag Buncic, F. Gabler, Gergely Palla, P. Csato, and R. Stock

Subjects
Physics, Nuclear reaction, Proton, Nuclear Theory, Hadron, General Physics and Astronomy, Elementary particle, Super Proton Synchrotron, Nuclear physics, Baryon, Rapidity, Atomic physics, Nuclear Experiment, Nucleon
Abstract

Net proton and negative hadron spectra for central Pb+Pb collisions at 158thinspthinspGeV per nucleon at the CERN Super Proton Synchrotron were measured and compared to spectra from lighter systems. Net baryon distributions were derived from those of net protons. Stopping (rapidity shift with respect to the beam) and mean transverse momentum {l_angle}p{sub T}{r_angle} of net baryons increase with system size. The rapidity density of negative hadrons scales with the number of participant nucleons for nuclear collisions, whereas their {l_angle}p{sub T}{r_angle} is independent of system size. The {l_angle}p{sub T}{r_angle} dependence upon particle mass and system size is consistent with larger transverse flow velocity at midrapidity for Pb+Pb compared to S+S central collisions. {copyright} {ital 1999} {ital The American Physical Society}

Published
1999

17. Λ hyperons in 2 A GeV Ni + Cu collisions

Author

J. A. Hauger, H. G. Ritter, S. Wang, Salvatore Costa, C. P. McParland, G. Rai, Renato Potenza, Antonio Insolia, J. C. Kintner, D. L. Olson, J. L. Romero, J. O. Rasmussen, B. K. Srivastava, Y. Shao, M. L. Gilkes, Sebastiano Albergo, J. L. Chance, M. A. McMahan, Z. Caccia, D. Cebra, R. P. Scharenberg, M. L. Tincknell, H. S. Matis, E. Hjort, H. Liu, J. Romanski, A. Scott, P. Warren, N. T. Porile, Y. Choi, M. A. Lisa, M. Justice, F. P. Brady, A. S. Hirsch, T. Wienold, R. L. McGrath, A. D. Chacon, D. Keane, D. Weerasundara, James B. Elliott, Cristina Tuve, M. D. Partlan, G.V. Russo, F. S. Bieser, K.L. Wolf, H. H. Wieman, and T. J. M. Symons

Subjects
Physics, Nuclear and High Energy Physics, Time projection chamber, 010308 nuclear & particles physics, Hyperon, Lambda, 01 natural sciences, Nuclear physics, Transverse plane, 0103 physical sciences, Transverse mass, Invariant mass, Multiplicity (chemistry), Impact parameter, Nuclear Experiment, 010306 general physics
Abstract

A sample of Lambda's produced in 2 A*GeV Ni + Cu collisions has been obtained with the EOS Time Projection Chamber at the Bevalac. Low background in the invariant mass distribution allows for the unambiguous demonstration of Lambda directed flow. The transverse mass spectrum at mid-rapidity has the characteristic shoulder-arm shape of particles undergoing radial transverse expansion. A linear dependence of Lambda multiplicity on impact parameter is observed, from which a total Lambda + Sigma^0 production cross section of $112 +/- 24 mb is deduced. Detailed comparisons with the ARC and RVUU models are made.

Published
1998

18. F emission in central Pb+Pb collisions at 158 GeV/u

Author

J. Gál, F. Pühlhofer, J. Dunn, Christina Markert, J. M. Nelson, Siegfried Wenig, Andreas Petridis, P. Csato, R. Stock, C. Bormann, Fuqiang Wang, D. D. Weerasundara, R. J. Porter, F. P. Brady, R. A. Barton, D. Schmischke, H. L. Caines, S. Margetis, S. Trentalange, D. J. Prindle, Peter Martin Jacobs, C. A. Whitten, R. Brockmann, V. Friese, E. Schäfer, A. Yu. Semenov, Predrag Buncic, Lee Stuart Barnby, Christof Roland, A. Piper, Marek Kowalski, Rainer Arno Ernst Renfordt, I. Huang, L. Wood, C. O. Blyth, Panagiota Foka, P. Szymanski, T. Ullrich, L. A. Hill, Helena Bialkowska, Jeffrey G. Reid, A. Mock, H. G. Fischer, J. Seyerlein, T. Wienold, F. Gabler, S. Schönfelder, S. Poziombka, Gyorgy Vesztergombi, F. Eckhardt, B. Lasiuk, A. M. Poskanzer, E. Gladysz, E. Skrzypczak, Torsten Henkel, X.-Z. Zhu, D. Flierl, H. Appelshäuser, Ferenc Sikler, N. Schmitz, Gunther Roland, Dieter Røhrich, Falk Pühlhofer, R. Zybert, G. Odyniec, G. Igo, M. Oldenburg, J. Zimányi, Z. Fodor, P. Freund, Jozsef Molnar, G.T.A. Squier, H. Hümmler, Thomas A. Trainor, J. Bächler, J. W. Harris, M. Vassiliou, Peter Graham Jones, G.E. Cooper, M. I. Ferguson, J. Sziklai, A. Billmeier, G. Pálla, W. Retyk, P. Seyboth, S. J. Bailey, D. Cebra, J. Günther, Apostolos Panagiotou, G. L. Melkumov, Kreso Kadija, V. Eckardt, Alexander Malakhov, Andrzej Rybicki, Rene Brun, A. Sandoval, S. Hegyi, M. Fuchs, J. G. Cramer, Marek Gaździcki, V. I. Kolesnikov, T. A. Yates, D. Vranic, H. Rudolph, I. Szentpetery, W. Rauch, M. Toy, J. Grebieszkow, H. Sann, J. Bartke, H. Ströbele, R. K. Bock, H. G. Ritter, Peter Levai, and D. Irmscher

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Large Hadron Collider, Yield (chemistry), Strangeness, Square (algebra), NA49 experiment
Abstract

Data on φ -production obtained by the CERN NA49 experiment for central Pb+Pb collisions at 158 GeV/u are presented. Compared with pp interactions the φ -yield shows substantial strangeness enhancement: the φ /π ratio is found to increase by a factor of 2.6 ± 0.6, which is approximately the square of the K/π enhancement.

Published
1998

19. Spectator Nucleons in Pb+Pb Collisions at 158 A·GeV

Author

P. Csato, Siegfried Wenig, D. Irmscher, J. W. Harris, P. B. Cramer, F. Gabler, B. Lasiuk, J. Dunn, Christina Markert, I. Sakrejda, Panagiota Foka, C. Bormann, J. Gál, A. M. Poskanzer, V. Eckardt, F. Eckhardt, J. G. Cramer, R. A. Barton, Peter Graham Jones, Marek Gaździcki, S. Poziombka, Jozsef Molnar, A. Mock, P. Freund, G. Odyniec, T. Wienold, Torsten Henkel, A. Sandoval, J. Zimányi, G. Igo, Z. Fodor, V. Friese, M. I. Ferguson, Lee Stuart Barnby, X. Z. Zhu, E. Skrzypczak, Gunther Roland, S. Hegyi, Norbert Schmitz, Christof Roland, A. Piper, J. Grebieszkow, M. Toy, H. Hümmler, E. Schäfer, M. Fuchs, A. Yu. Semenov, S. J. Bailey, F. P. Brady, I. Huang, H. Appelshäuser, Andreas Petridis, L. A. Hill, C. O. Blyth, Rainer Arno Ernst Renfordt, M. Vassiliou, Andrzej Rybicki, T. Ullrich, S. Margetis, W. Rauch, L. Wood, Fuqiang Wang, Jeffrey G. Reid, G. L. Melkumov, N. Buncic, Dieter Røhrich, P. Seyboth, W. Retyk, F. Pühlhofer, S. White, J. Seyerlein, H. Sann, J. Sziklai, H. G. Ritter, R. Stock, G.E. Cooper, P. Chan, J. M. Nelson, Peter Levai, Kreso Kadija, I. Szentpetery, D. Flierl, T. A. Yates, Ferenc Sikler, Alexander Malakhov, D. Vranic, D. D. Weerasundara, Thomas A. Trainor, R. Brockmann, J. Bartke, S. Schönfelder, Gyorgy Vesztergombi, D. Schmischke, H. Rudolph, H. G. Fischer, Peter Martin Jacobs, H. Ströbele, Helena Bialkowska, Predrag Buncic, R. K. Bock, R. J. Porter, G. T. A. Squier, D. J. Prindle, G. Pálla, Marek Kowalski, C. A. Whitten, R. Zybert, E. Gladysz, D. Cebra, J. Günther, S. Trentalange, Apostolos Panagiotou, P. Gorodetsky, H. L. Caines, J. Bächler, and V. I. Kolesnikov

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Particle physics, Large Hadron Collider, Nuclear Theory, Hadron, Nuclear physics, Deuterium, Nuclear fusion, Neutron, Impact parameter, Nuclear Experiment, Nucleon
Abstract

The composition of forward-going projectile spectator matter in fixed-target Pb+Pb collisions at 158 A · GeV at the CERN SPS has been studied as a function of centrality. The data were measured with the NA49 veto calorimeter. We observe that forward-going spectator matter in central collisions consists of 9 neutrons, 7 protons, and half a deuteron on average. At large impact parameters most spectator nucleons are bound in fragments. The relative resolution of the average impact parameter derived from the measurement of spectator neutrons is roughly 19% in the range from zero to half maximum impact parameters.

Published
1998

20. Directed and elliptic flow in 158 GeV/nucleon Pb + Pb collisions

Author

J. W. Harris, Jozsef Molnar, F. P. Brady, V. Eckardt, K. Kadija, D. Flierl, D. D. Weerasundara, G.T.A. Squier, M. I. Ferguson, A. Sandoval, D. Irmscher, Siegfried Wenig, D. Schmischke, C. O. Blyth, S. Hegyi, M. Fuchs, C. Bormann, R. J. Porter, S. Margetis, H. G. Fischer, Andrzej Rybicki, H. Appelshäuser, R. A. Barton, J. G. Cramer, S. Schönfelder, Gyorgy Vesztergombi, Helena Bialkowska, D. J. Prindle, Dieter Røhrich, Rene Brun, H. G. Ritter, Marek Gaździcki, Christof Roland, A. Piper, T. Wienold, R. Zybert, S. Voloshin, G.E. Cooper, Rainer Arno Ernst Renfordt, E. Skrzypczak, Marek Kowalski, G. Pálla, Peter Levai, M. Toy, Andreas Petridis, I. Huang, L. Wood, Panagiota Foka, E. Gladysz, F. Eckhardt, P. Freund, J. Sziklai, Ferenc Sikler, F. Pühlhofer, G. L. Melkumov, G. Odyniec, J. Grebieszkow, J. Bächler, M. Vassiliou, V. I. Kolesnikov, G. Igo, M. Oldenburg, E. Schäfer, J. M. Nelson, A. Yu. Semenov, R. Brockmann, P. Csato, R. Stock, J. Seyerlein, Norbert Schmitz, Peter Martin Jacobs, T. A. Yates, D. Vranic, Predrag Buncic, Gunther Roland, P. Seyboth, F. Gabler, H. Rudolph, T. Ullrich, I. Szentpetery, Alexander Malakhov, L. A. Hill, D. Cebra, J. Günther, Peter Graham Jones, S. Trentalange, Apostolos Panagiotou, C. A. Whitten, J. Dunn, Christina Markert, V. Friese, Thomas A. Trainor, S. Poziombka, J. Zimányi, A. Mock, Torsten Henkel, B. Lasiuk, Z. Fodor, H. Hümmler, Jeffrey G. Reid, W. Retyk, W. Rauch, H. Sann, J. Bartke, J. Gál, H. Ströbele, R. K. Bock, Fuqiang Wang, A. M. Poskanzer, Lee Stuart Barnby, H. Caines, and S. J. Bailey

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Elliptic flow, Physics::Fluid Dynamics, Nuclear physics, Pion, Flow (mathematics), Transverse momentum, Rapidity, Nuclear Experiment, Nucleon, Beam (structure)
Abstract

The directed and elliptic flow of protons and charged pions has been observed from the semi-central collisions of a 158 GeV/nucleon Pb beam with a Pb target. The rapidity and transverse momentum dependence of the flow has been measured. The directed flow of the pions is opposite to that of the protons at high rapidity but both exhibit negative flow at low p t . The elliptic flow of both is fairly independent of rapidity but rises with p t .

Published
1998

21. Dynamics of radial collective energy in near central collisions for1AGeVAu+C

Author

A. Scott, H. Sann, P. Danielewicz, M. A. McMahan, N. N. Ajitanand, T. Wienold, S. Wang, J. A. Hauger, J. B. Elliott, T. J. M. Symons, J. Romanski, F. P. Brady, R. Potenza, D. Keane, P. Chung, A. D. Chacon, H. H. Wieman, M. L. Gilkes, S. Albergo, M. Justice, P. Warren, V. Lindenstruth, J. L. Chance, S. Costa, H. G. Ritter, M. L. Tincknell, A. S. Hirsch, D. Cebra, N. T. Porile, R. L. McGrath, G. V. Russo, E. L. Hjort, G. Rai, J. O. Rasmussen, Roy A. Lacey, C. P. McParland, M. D. Partlan, Z. Caccia, D. L. Olson, A. Insolia, R. P. Scharenberg, H. S. Matis, M. A. Lisa, Y. Choi, J. Lauret, John M. Alexander, B. K. Srivastava, J. L. Romero, Y. Shao, C. Tuve, Wolfgang Müller, F. S. Bieser, K.L. Wolf, and J. C. Kintner

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Transverse plane, Thermal, Quasiparticle, Coulomb, Atomic physics, Nuclear Experiment, Kinetic energy, Excitation, Energy (signal processing)
Abstract

Transverse kinetic energies of individual fragments have been measured over a broad range of emitter excitation energies for the reaction 1AGeV Au+C. For excitation energies leading to large intermediate mass fragment multiplicities, these transverse energies require large collective radial expansion of the emitting systems. However, the traditional decomposition of the transverse energy into a thermal component and a Coulomb and collective component proportional to the fragment mass cannot account for this expansion. Expansion velocities show an increase with decreasing fragment Z and thus indicate fractionation of the collective energy for the expanding system. This collective energy increases with emitter excitation up to about 50{percent} of the energy deposited for a nuclear system with total energy {approximately}12AMeV. The bulk of the collective energy is carried away by ejectiles of Z{le}3. {copyright} {ital 1998} {ital The American Physical Society}

Published
1998

22. Multifragmentation of the remnant produced in the reaction of1AGeV gold with carbon

Author

M. A. McMahan, Cristina Tuve, J. O. Rasmussen, M. D. Partlan, C. P. McParland, F. P. Brady, Y. Shao, R. P. Scharenberg, and K. Wolf, S. Wang, H. S. Matis, V. Lindenstruth, M. A. Lisa, J. C. Kintner, A. Scott, J. L. Chance, H. Sann, Y. Choi, D. Cebra, H. G. Ritter, F. S. Bieser, P. Warren, Renato Potenza, J. B. Elliott, D. Keane, B. K. Srivastava, Sebastiano Albergo, E. L. Hjort, J. L. Romero, H. H. Wieman, G. Rai, T. J. M. Symons, M. L. Gilkes, Z. Caccia, T. Wienold, J. A. Hauger, D. L. Olson, J. Romanski, Wolfgang Müller, M. L. Tincknell, N. T. Porile, Salvatore Costa, Andrew S. Hirsch, A. Insolia, A. D. Chacon, G.V. Russo, and M. Justice

Subjects
Physics, Nuclear and High Energy Physics, Isotope, Atomic number, Multiplicity (chemistry), Atomic physics, Nuclear Experiment, Nuclear matter, Nucleon, Excitation, Charged particle, Effective nuclear charge
Abstract

A high-statistics exclusive study of the multifragmentation of 1A GeV gold on carbon has been performed. Particles with Z{le}2 show evidence of emission in a first prompt stage as well as in a second equilibrium stage whereas fragments with Z{ge}3 appear to be emitted essentially only in the second stage. Two methods for the separation of the Z{le}2 particles into the two stages are given and they are in agreement. The yields for each stage are determined as a function of the event charged particle multiplicity m. The mass, nuclear charge, excitation energy per nucleon, and temperature of the remnant left after the first stage and their fluctuations have been determined as a function of m. The expansion of the remnant to fragment freeze-out is examined. The freeze-out temperature is determined from double isotope ratios as a function of m and isentropic trajectories are obtained in the temperature-density plane. The caloric curve shows a monotonic increase with excitation energy. Some of the energy is in the form of radial flow. Overall, the results are consistent with a previous statistical analysis of the data which suggests that, over a certain range of excitation energies, multifragmentation involves a continuous phase transition. {copyright}more » {ital 1998} {ital The American Physical Society}« less

Published
1998

23. ΔResonance Production inN58i+CuCollisions atE=1.97AGeV

Author

J. O. Rasmussen, A. S. Hirsch, Alwyn C. Scott, Sebastiano Albergo, T. J. M. Symons, Y. Shao, M. L. Gilkes, Y. Choi, G.V. Russo, M. A. McMahan, J. L. Romero, G. Rai, M. L. Tincknell, N. T. Porile, M. Justice, P. Warren, F. S. Bieser, K.L. Wolf, S. Wang, E. L. Hjort, Z. Caccia, M. D. Partlan, H. H. Wieman, R. P. Scharenberg, H. S. Matis, D. Keane, J. L. Chance, D. L. Olson, D. Cebra, Renato Potenza, T. Wienold, J. B. Elliott, J. C. Kintner, A. D. Chacon, Salvatore Costa, A. Insolia, C. P. McParland, J. Romanski, M. A. Lisa, B. K. Srivastava, F. P. Brady, Cristina Tuve, H. G. Ritter, and J. A. Hauger

Subjects
Baryon, Nuclear physics, Physics, Nuclear reaction, Hadron, General Physics and Astronomy, Resonance, Production (computer science), Elementary particle, Invariant mass, Atomic physics, Nuclear Experiment, Delta baryon
Abstract

Invariant mass analyses of (p,{pi}{sup {plus_minus}}) pairs in {sup 58}Ni+Cu collisions at 1.97A GeV have been performed and show correlations resulting from the decays of the {Delta} resonance, the {Lambda} baryon, and possibly the N{sup {asterisk}}(1440) resonance. A reduction in the {Delta} mass is observed and the mass reduction increases with collision centrality. Events generated by the relativistic cascade model (ARC) also reveal a mass reduction. The mass reduction is related to the size of the reaction volume and the details of {Delta} production mechanisms in heavy ion collisions. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

24. Pion Flow and Antiflow in1.15AGeVAu+Au

Author

G. Rai, D. Keane, A. Scott, F. S. Bieser, M. L. Tincknell, K.L. Wolf, Y. Shao, N. T. Porile, H. H. Wieman, G.V. Russo, Renato Potenza, M. L. Gilkes, J. B. Elliott, T. J. M. Symons, J. O. Rasmussen, J. C. Kintner, J. L. Romero, A. D. Chacon, Salvatore Costa, B. K. Srivastava, A. Insolia, T. Wienold, M. A. McMahan, Sebastiano Albergo, Cristina Tuve, H. G. Ritter, Andrew S. Hirsch, R. P. Scharenberg, P. Warren, F. P. Brady, H. S. Matis, E. L. Hjort, D. L. Olson, J. A. Hauger, Y. Choi, M. D. Partlan, S. Wang, Z. Caccia, M. Justice, J. Romanski, M. A. Lisa, J. L. Chance, D. Cebra, and C. P. McParland

Subjects
Nuclear physics, Physics, Particle physics, Pion, Flow (mathematics), TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, General Physics and Astronomy, Impact parameter
Abstract

Transverse flow has been studied as a function of impact parameter for pions and protons from the reaction 1.15A GeV {sup 197}Au+{sup 197}Au. We observe an {open_quotes}antiflow{close_quotes} behavior for both {pi}{sup +} and {pi}{sup -} in peripheral collisions. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

25. The Energy Dependence of Flow in Ni Induced Collisions from400Ato1970AMeV

Author

M. Justice, R. P. Scharenberg, H. S. Matis, T. J. M. Symons, M. L. Gilkes, B. K. Srivastava, Y. Choi, Sebastiano Albergo, F. S. Bieser, S. Wang, K.L. Wolf, Andrew S. Hirsch, T. Wienold, Renato Potenza, D. Keane, J. B. Elliott, Antonio Insolia, C. P. McParland, J. L. Romero, H. H. Wieman, Salvatore Costa, J. C. Kintner, F. P. Brady, M. A. Lisa, A. Scott, M. A. McMahan, J. L. Chance, D. Cebra, P. Warren, E. L. Hjort, G. Rai, J. Romanski, Cristina Tuve, M. L. Tincknell, N. T. Porile, Z. Caccia, M. D. Partlan, A. D. Chacon, G.V. Russo, Y. Shao, J. O. Rasmussen, D. L. Olson, H. G. Ritter, and J. A. Hauger

Subjects
Physics, 010308 nuclear & particles physics, Computer Science::Information Retrieval, General Physics and Astronomy, chemistry.chemical_element, Nuclear matter, 01 natural sciences, 7. Clean energy, Copper, Nuclear physics, Nickel, chemistry, Flow (mathematics), 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Scaling, Energy (signal processing)
Abstract

We study the energy dependence of collective (hydrodynamic-like) nuclear matter flow in (400{endash}1970){ital A} MeV Ni+Au and (1000{endash}1970){ital A} MeV Ni+Cu reactions. The flow increases with energy, appears to reach a maximum, and then to decrease at higher energies. A way of comparing the energy dependence of flow values for different projectile-target mass combinations is introduced, which demonstrates a more-or-less common scaling behavior among flow values from different systems. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

26. A multiple sampling time projection ionization chamber for nuclear fragment tracking and charge measurement

Author

H. Sann, F. P. Brady, U. Lynen, C. E. Tull, M. L. Gilkes, J. L. Romero, P. Warren, F. Bieser, J.C. Chance, G. Bauer, V. Lindenstruth, W.F. Christie, and Walter F. J. Müller

Subjects
Physics, Nuclear and High Energy Physics, Time projection chamber, Spectrometer, Physics::Instrumentation and Detectors, Projectile, Nuclear Theory, Detector, Tracking (particle physics), Nuclear physics, Ionization, Ionization chamber, Nuclear Experiment, Projection (set theory), Instrumentation
Abstract

A detector has been developed for the tracking and charge measurement of the projectile fragment nuclei produced in relativistic nuclear collisions. This device, MUSIC II, is a second generation Multiple Sampling Ionization Chamber (MUSIC), and employs the principles of ionization and time projection chambers. It provides unique charge determination for charges Z≥6, and excellent track position measurement. MUSIC II has been used most recently with the EOS (Equation of State) TPC and other EOS Collaboration detectors. Earlier it was used with other systems in experiments at the Heavy Ion Superconducting Spectrometer (HISS) facility at Lawrence Berkeley Laboratory and the ALADIN spectrometer at GSI.

Published
1997

27. Preliminary results on Pb+Pb collisions from the Grid-TOF data analysed in Budapest

Author

S. Schönfelder, Gyorgy Vesztergombi, J. W. Harris, L. A. Hill, G. E. Cooper, M. A. Bloomer, I. Huang, L. Wood, V. Eckardt, X.-Z. Zhu, J. Dunn, J. Bächler, M. Vassiliou, B. Lasiuk, C. Bormann, D. Vranic, I. Derado, K. Runge, I. Szentpetery, A. M. Poskanzer, F. P. Brady, P. Seyboth, P. B. Cramer, Jozsef Molnar, M. I. Ferguson, R. Brockmann, J. G. Cramer, A. Piper, K. Kadija, S. Euler, S. Trentalange, Marek Gaździcki, W. Heck, P. Csato, D. Irmscher, G. Odyniec, H. Appelshäuser, R. Stock, H. G. Fischer, M. Toy, J. Grebieszkow, C. O. Blyth, N. Schmitz, Dieter Røhrich, Thomas A. Trainor, P. Chan, E. Skrzypczak, T. Wienold, Peter Levai, Panagiota Foka, F. Eckhardt, J. Gál, J. Zimányi, H. L. Caines, P. Jacobs, F. Pühlhofer, G. Igo, J. M. Nelson, H. G. Ritter, M. A. Howe, Z. Fodor, A. Petridis, Predrag Buncic, C. A. Whitten, T. Alber, P. Freund, G. Pálla, J. Gunther, E. Schäfer, J. Seyerlein, W. Rauch, H. Ströbele, Helena Bialkowska, H. Sann, R. Zybert, J. Bartke, D. J. Prindle, Marek Kowalski, H. Rudolph, E. Gladysz, F. Bieser, J. Sziklai, J. W. Mitchell, D. Cebra, Apostolos Panagiotou, A. Kühmichel, A. Sandoval, S. Hegyi, M. Fuchs, A. Mock, Siegfried Wenig, S. Margetis, W. Retyk, Ferenc Sikler, Peter Graham Jones, R. K. Bock, and R. Renfordt

Subjects
Condensed Matter::Quantum Gases, Physics, Nuclear and High Energy Physics, Large Hadron Collider, Physics::Instrumentation and Detectors, Nuclear Theory, Detector, Hadron, General Physics and Astronomy, Grid, Tracking (particle physics), Particle identification, Spectral line, Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment, NA49 experiment
Abstract

The first results from the NA49 experiment, using a large acceptance tracking detector with particle identification, are presented which have been obtained from the recent Pb-ion run at the CERN SPS. Preliminary spectra of kaons and protons identified by the Grid-TOF detector as well as Bose-Einstein correlations are shown.

Published
1996

28. Hadron yields and hadron spectra from the NA49 experiment

Author

D. D. Weerasundara, C. Bormann, J. Bächler, D. Schmischke, M. Vassiliou, P. Seyboth, D. Irmscher, Rainer Arno Ernst Renfordt, A. Piper, H. G. Fischer, Ferenc Sikler, C. O. Blyth, Siegfried Wenig, J. Sziklai, Kreso Kadija, F. Pühlhofer, G.E. Cooper, H. G. Ritter, Peter Levai, J. Gál, D. Cebra, J. Günther, J. W. Harris, J. M. Nelson, M. Toy, Apostolos Panagiotou, G. L. Melkumov, I. Huang, L. Wood, J. Grebieszkow, S. Schönfelder, V. Eckardt, P. B. Cramer, X.-Z. Zhu, G. Odyniec, J. G. Cramer, Gyorgy Vesztergombi, Andreas Petridis, F. P. Brady, P. Freund, Lee Stuart Barnby, M. Cyprian, Peter Graham Jones, Marek Gaździcki, N. Bunicic, J. W. Mitchell, Christof Roland, A. M. Poskanzer, H. Appelshäuser, Jozsef Molnar, R. Bock, M. I. Ferguson, Helena Bialkowska, S. Margetis, T. Wienold, E. Skrzypczak, S. Poziombka, R. Zybert, S. Trentalange, J. Zimányi, R. Brockmann, V. I. Kolesnikov, T. A. Yates, D. Vranic, D. J. Prindle, H. Rudolph, D. Flierl, Peter Martin Jacobs, Marek Kowalski, I. Szentpetery, Predrag Buncic, S. Euler, E. Gladysz, A. Mock, Z. Fodor, H. Hümmler, G. Pálla, Andrzej Rybicki, E. Schäfer, A. Yu. Semenov, A. Sandoval, J. Seyerlein, H. L. Caines, S. Hegyi, M. Fuchs, W. Retyk, Alexander Malakhov, P. Csato, R. Stock, F. Gabler, B. Lasiuk, I. Derado, Panagiota Foka, O. Dietz, L. A. Hill, Thomas A. Trainor, P. Chan, H. Sann, J. Dunn, Christina Markert, S. Afanasiev, F. Eckhardt, J. Bartke, G. Igo, H. Ströbele, W. Rauch, N. Schmitz, Dieter Røhrich, Gunther Roland, M. A. Howe, C. A. Whitten, and T. Alber

Subjects
Physics, Nuclear physics, S system, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, Hadron, Nuclear Experiment, Nucleon, Central region, NA49 experiment, Spectral line
Abstract

Preliminary inclusive spectra of negative hadrons, net protons and neutral strange particles are presented, measured by the NA49 experiment in central Pb+Pb collisions at 158 GeV per nucleon. Comparison of their yields with those from the lighter S+S system suggests that the yields scale approximately with the number of participating nucleons.

Published
1996

29. Stopping and collective effects at SPS energies

Author

J. Dunn, Christina Markert, Siegfried Wenig, M. A. Howe, S. Poziombka, Serguei Afanasiev, F. Pühlhofer, J. Zimányi, J. G. Cramer, J. Sziklai, C. A. Whitten, C. O. Blyth, M. I. Ferguson, J. M. Nelson, A. M. Poskanzer, T. Alber, Lee Stuart Barnby, F. P. Brady, W. Rauch, S. Schönfelder, Gyorgy Vesztergombi, Andreas Petridis, D. Prindle, Norbert Schmitz, L. A. Hill, C. Bormann, Helena Bialkowska, G. L. Melkumov, M. Vassiliou, Marek Kowalski, R. Zybert, S. Margetis, Peter Martin Jacobs, H. Sann, Marek Gaździcki, R. Brockmann, E. Gladysz, Predrag Buncic, Peter Graham Jones, G. Odyniec, E. Schäfer, Jozsef Molnar, D. Irmscher, R. Bock, J. W. Mitchell, P. Seyboth, A. Yu. Semenov, S. Euler, J. Bartke, M. Toy, T. A. Yates, D. Vranic, F. Eckhardt, M. Cyprian, Gunther Roland, J. Grebieszkow, Christof Roland, P. Chan, J. W. Harris, H. Rudolph, H. G. Ritter, E. Skrzypczak, P. B. Cramer, N. Buncic, Rainer Arno Ernst Renfordt, J. Seyerlein, Peter Levai, A. Piper, H. Ströbele, G. Igo, J. Gál, D. Cebra, J. Günther, V. Eckardt, S. Trentalange, Apostolos Panagiotou, T. A. Trainor, I. Szentpetery, I. Huang, Ferenc Sikler, P. Freund, L. Wood, D. D. Weerasundara, D. Schmischke, D. Flierl, H. G. Fischer, Dieter Røhrich, H. Appelshäuser, G.E. Cooper, G. Pálla, X. Z. Zhu, K. Kadija, A. Sandoval, S. Hegyi, M. Fuchs, J. Bächler, V. I. Kolesnikov, H. L. Caines, Andrzej Rybicki, T. Wienold, P. Csato, R. Stock, Panagiota Foka, O. Dietz, F. Gabler, B. Lasiuk, I. Derado, A. Mock, Z. Fodor, H. Hümmler, W. Retyk, and Alexander Malakhov

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Proton, Spectrometer, Nuclear Theory, Collision, Projection (linear algebra), Nuclear physics, Time of flight, Energy flow, Rapidity, Nuclear Experiment, Nucleon
Abstract

We discuss preliminary data on stopping for central Pb + Pb collisions at 158 GeV/nucleon. The (net) proton rapidity density measured by the NA49 Time Projection Chambers, NA49 Time of Flight and the NA44 spectrometer is presented. Slightly higher stopping is observed relative to S + S at 200 GeV/nucleon. The rapidity density exhibits a plateau around mid-rapidity which is qualitatively different from results at the AGS and BEVALAC/SIS energies. The second part of the paper discusses the azimuthal correlation of the energy flow. Preliminary results reveal that the ‘fireball’ preserves the information of the collision geometry even at SPS energies.

Published
1996

30. In-Plane Retardation of Collective Expansion inAu+AuCollisions

Author

F. P. Brady, M. A. McMahan, H. G. Ritter, J. L. Romero, V. Lindenstruth, R. P. Scharenberg, J. L. Chance, F. S. Bieser, H. S. Matis, K.L. Wolf, D. Cebra, A. Scott, Antonio Insolia, D. L. Olson, Y. Choi, M. L. Tincknell, J. Romanski, D. Keane, D. Weerasundara, A. D. Chacon, N. T. Porile, S. Wang, Cristina Tuve, M. A. Lisa, Sebastiano Albergo, G.V. Russo, H. H. Wieman, Andrew S. Hirsch, H. Liu, G. Rai, Renato Potenza, M. L. Gilkes, J. B. Elliott, J. O. Rasmussen, Z. Caccia, C. P. McParland, J. C. Kintner, P. Warren, Salvatore Costa, M. D. Partlan, E. L. Hjort, J. A. Hauger, Y. Shao, B. K. Srivastava, M. Justice, and T. J. M. Symons

Subjects
Physics, In plane, Classical mechanics, General Physics and Astronomy
Published
1996

31. ReactionC13(n,p)13B at 65 MeV

Author

D. Pocanic, K. Wang, B. McEachern, S. S. Hanna, J. L. Romero, C.M. Castaneda, James R. Drummond, C. J. Martoff, F. P. Brady, and D. S. Sorenson

Subjects
Physics, Nuclear and High Energy Physics, Electric dipole moment, Crystallography, Degree (graph theory), Giant resonance, Isospin, Excited state, Resonance, Spin (physics), Ground state
Abstract

The reaction {sup 13}C({ital n},{ital p}){sup 13}B has been studied at {ital E}{sub {ital n}}=65 MeV. Cross sections were measured for transitions to the ground state and excited states of {sup 13}B from 0{degree} to 40{degree}. The 0{degree} cross section to the ground state gives a value of 179{plus_minus}20 MeVfm{sup 3} for {ital V}{sub {sigma}{tau}}{sup {ital c}}, the spin-isospin central part of the volume integral of the effective {ital N}-{ital N} interaction. A theoretical calculation, 181.3 MeVfm{sup 3}, is in good agreement with this result. Distorted-wave impulse-approximation calculations are compared with the experimental angular distributions. Good agreement is obtained for the dominant Gamow-Teller transition to the ground state of {sup 13}B. The evidence obtained here, together with results from the analogous reaction {sup 13}C({pi}{sup {minus}},{gamma}){sup 13}B, suggests that transitions to states at 6.5 and 7.6 MeV are spin dipole in character and that the broad resonance at 10.2 MeV is chiefly the analog of the giant {ital E}1 resonance in {sup 13}C. {copyright} {ital 1996 The American Physical Society.}

Published
1996

32. Transverse Energy Production inPb208+ Pb Collisions at 158 GeV per Nucleon

Author

A. Petridis, H. L. Caines, H. Sann, H. G. Ritter, J. Kecskemeti, P. Chan, R. Bock, X. Z. Zhu, Gergely Palla, J. Seyerlein, I. Derado, D. J. Prindle, M. Fuchs, F. Eckhardt, J. Bartke, Panagiota Foka, M. A. Bloomer, P. Seyboth, C. Bormann, P. B. Cramer, J. G. Cramer, P. Buncic, Zoltan Fodor, A. Sandoval, C. O. Blyth, G. Igo, R. Brockmann, Rainer Arno Ernst Renfordt, S. Margetis, E. Skrzpczak, E. Gładysz, Helena Bialkowska, J. Sziklai, T. A. Trainor, Kreso Kadija, P. Csato, I. Szentpetery, R. Stock, P. Freund, H. G. Fischer, J. G̈nther, S. Schönfelder, A. Piper, Marek Kowalski, J. Palinkas, Gyorgy Vesztergombi, Ferenc Sikler, F. P. Brady, Siegfried Wenig, H. Rudolph, L. A. Hill, C. A. Whitten, M. I. Ferguson, A. M. Poskanzer, S. Hegyi, G. Odyniec, I. Huang, G. E. Cooper, B. Lasiuk, L. Wood, W. Rauch, H. Ströbele, J. Bächler, M. Toy, J. Grebieszkow, J. M. Nelson, T. Wienold, D. Irmscher, J. Dunn, T. Alber, A. K̈hmichel, Peter Graham Jones, S. Euler, J. Gál, M. A. Howe, R. Zybert, W. Retyk, P. Jacobs, F. P̈hlhofer, D. Cebra, S. Trentalange, Apostolos Panagiotou, A. Mock, F. Bieser, J. W. Mitchell, J. Zimányi, V. Eckardt, K. Runge, Norbert Schmitz, J. W. Harris, E. Schäfer, M. Vassiliou, M. Gaadzicki, W. Heck, D. Vranic, Dieter Røhrich, and H. Appelshäuser

Subjects
Particle physics, Energy loss, Energy (psychological), Energy density, General Physics and Astronomy, Humanities
Abstract

Author(s): Margetis, S.; Alber, T.; Appelshauser, H.; Bachler, J.; Bartke, J.; Bialkowska, H.; Bieser, F.; Bloomer, M.A.; Blyth, C.O.; Bock, R.; Bormann, C.; Brady, F.P.; Brockmann, R.; Buncic, P.; Caines, H.L.; Cebra, D.; Chan, P.; Cooper, G.E.; Cramer, J.G.; Cramer, P.B.; Csato, P.; Derado, I.; Dunn, J.; Eckardt, V.; Eckhardt, F.; Euler, S.; Ferguson, M.I.; Fischer, H.G.; Fodor, Z.; Foka, P.; Freund, P.; Fuchs, M.; Gal, J.; Gasdzicki, M.; Gladysz, E.; Grebieszkow, J.; Gunther, J.; Harris, J.W.; Heck, W.; Hegyi, S.; Hill, L.A.; Huang, I.; Howe, M.A.; Igo, G.; Irmscher, D.; Jacobs, P.; Jones, P.G.; Kadija, K.; Kecskemeti, J.; Kowalski, M.; Kuhmichel, A.; Lsdiuk, B.; Margetis, S.; Mitchell, J.W.; Mock, A.; Nelson, J.M.; Odyniec, G.J.; Palinkas, J.; Palla, G.; Panagiotou, A.D.; Petridis, A.; Piper, A.; Poskanzer, A.M.; Prindle, D.J.; Puhlhofer, F.; Rauch, W.; Renfordt, R.; Retyk, W.; Ritter, Hans G.; Rohrich, D.; Rudolph, H.; Runge, K.; Sandoval, A.; Sann, H.; Schafer, E.; Schmitz, N.; Schonfelder, S.; Seyboth, P.; Seyerlein, J.; Sikler, F.; Skrzypczak, E.; Stock, R.; Stroebele, H.; Szentpetery, I.; Sziklai, J.

Published
1995

33. Radial Flow inAu+AuCollisions atE=(0.25−1.15)AGeV

Author

J. Romanski, M. A. Lisa, M. A. McMahan, Z. Caccia, Y. Shao, M. Justice, A. Scott, D. Keane, Cristina Tuve, F. S. Bieser, R. P. Scharenberg, H. S. Matis, H. H. Wieman, K.L. Wolf, J. L. Chance, D. Cebra, Antonio Insolia, F. P. Brady, B. K. Srivastava, Gary Westfall, Y. Choi, D. L. Olson, M. D. Partlan, G. V. Russo, S. Wang, J. O. Rasmussen, T. J. M. Symons, A. D. Chacon, J. A. Hauger, P. Warren, C. P. McParland, Renato Potenza, Sebastiano Albergo, G. Rai, J. B. Elliott, E. L. Hjort, J. L. Romero, H. G. Ritter, Andrew S. Hirsch, M. L. Gilkes, Salvatore Costa, M. L. Tincknell, N. T. Porile, and J. C. Kintner

Subjects
Physics, 010308 nuclear & particles physics, media_common.quotation_subject, General Physics and Astronomy, 16. Peace & justice, 01 natural sciences, Radial velocity, Quantum mechanics, 0103 physical sciences, Justice (virtue), Radial flow, 010306 general physics, media_common, Mathematical physics
Abstract

Author(s): Lisa, M.A.; Albergo, S.; Bieser, F.; Brady, F.P.; Caccia, Z.; Cebra, D.A.; Chacon, A.D.; Chance, J.L.; Choi, Y.; Costa, S.; Elliott, J.B.; Gilkes, M.L.; Huager, J.A.; Hirsch, A.S.; Hjort, E.L.; Insolia, A.; Justice, M.; Keane, D.; Kintner, J.; Matis, H.S.; McMahan, M.; McParland, C.; Olson, D.L.; Partlan, M.D.; Porile, N.T.; Potenza, R.; Rai, G.; Rasmussen, J.O.; Ritter, Hans G.; Romanski, J.; Romero, J.L.; Russo, G.V.; Scharenberg, R.P.; Scott, A.; Shao, Y.; Srivastava, B.K.; Symons, T.J.M.; Tincknell, M.L.; Tuve, C.; Wang, S.; Warren, P.; Westfall, G.D.; Wieman, H.H.; Wolf, K.

Published
1995

34. Comment on 'Photon spectrum of the neutron-proton Bremsstrahlung at 170 MeV': Contributions of np → dγ to inclusive photon energy spectra from np and pd collisions near 200 MeV

Author

F. P. Brady, J. E. Koster, R. O. Nelson, J. L. Romero, Stephen A. Wender, and D.R. Mayo

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Photon, Proton, Spectrum (functional analysis), Bremsstrahlung, Neutron, Atomic physics, Photon energy, Photon spectra, Spectral line
Abstract

Several years ago, a measured photon energy spectrum from np collisions was presented as a measurement of free np Bremsstrahlung, and subsequently theoretical groups compared the data to their model calculations of the process np → npγ [F. Malek, A. Nifenecker, J.A. Pinston, F. Schussler, S. Drissi, J. Julien, Phys. Lett. B 266 (1991) 391]. We point out that in np collisions, np capture ( np → dγ ) is important and cannot be ignored. It contributes approximately 30% of the cross section for photons above 40 MeV. Capture also makes a significant contribution to the photon spectra produced in p - d collisions, and possibly has a role in p -nucleus collisions. In the former case, better agreement between theory and experiment is obtained when (quasifree) capture is included.

Published
1995

35. Patient positioning for protontherapy using a proton range telescope

Author

R.S King, J. H. Osborne, F. P. Brady, B.H Kusko, W. Chu, I Mirshad, M. D. Partlan, H Kubo, J. L. Romero, Inder K. Daftari, D. Cebra, and W. Caskey

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Proton, business.industry, Nuclear Theory, Monte Carlo method, Detector, Radiation, law.invention, Telescope, Optics, law, Physics::Accelerator Physics, Nuclear Experiment, business, Instrumentation, Proton therapy, Beam (structure)
Abstract

A method is described for imaging integrated density along the beam path in phantoms that makes use of high energy proton beams. An application of the technique is in the positioning of patients in a proton therapy radiation facility. It makes use of a proton range telescope for density variation and X - Y detectors for planar positioning. The principle of the method was tested at a proton energy of 66 MeV. Good visual quality is seen in the tests. The measurements are compared with detailed Monte Carlo simulations, and good agreement is found. We apply the simulations to high energy proton beams (245 MeV) and show that the method should provide good visual quality and sensitivity for positioning at the higher energies necessary for whole body therapy.

Published
1995

36. Fragment mass dependence ofpTat GeV per nucleon energies

Author

G. P. Grim, H. Sann, T. J. M. Symons, J. L. Romero, Isao Tanihata, Peter J. Lindstrom, H. J. Crawford, J. C. Young, D.L. Olson, U. Lynen, T. Kobayashi, C. E. Tull, J. L. Chance, H. Wieman, W. B. Christie, F. P. Brady, and W. F. J. Müller

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Computer Science::Information Retrieval, Nuclear Theory, Transverse momentum, Light particle, Nuclear Experiment, Nucleon
Abstract

Measurements of the transverse momenta ([ital p][sub [ital T]]) of medium and heavy mass projectile fragments for a range of projectile nuclei ([sup 40]Ar, [sup 93]Nb, [sup 139]La, [sup 197]Au) have been carried out. It is found that the width of the transverse momentum distributions increases more rapidly with projectile and fragment mass than predicted by models based on nucleon momenta in the projectile nuclei. The distributions can be fit by including an additional transverse momentum, [ital p][sub [ital B]] (for Bounce). The extracted values of [ital p][sub [ital B]]/[ital A][sub [ital F]] increase with decreasing [ital A][sub [ital F]], and extrapolations to small [ital A][sub [ital F]] appear to be consistent with the mean values of reaction-plane-projected [ital p][sub [ital T]] per nucleon for light particle (e.g., nucleon) bounce-off.''

Published
1994

37. Measurements and analysis of neutron elastic scattering at 65 MeV

Author

J. L. Romero, B. McEachern, D. S. Sorenson, J. H. Osborne, F. P. Brady, L. Hansen, E. L. Hjort, and James R. Drummond

Subjects
Physics, Nuclear reaction, Elastic scattering, Nuclear and High Energy Physics, Proton, Scattering, chemistry.chemical_element, Neutron scattering, Semimetal, chemistry, Neutron, Atomic physics, Nuclear Experiment, Tin
Abstract

Elastic scattering cross sections for 65 MeV neutrons have been measured for natural targets of C, Si, Ca, Fe, Sn, and Pb at laboratory angles from 6\ifmmode^\circ\else\textdegree\fi{} to 45\ifmmode^\circ\else\textdegree\fi{}. A unique, compact detection system consisting of a ${\mathrm{CH}}_{2}$ (proton) converter and large-acceptance, wire-chamber-based, recoil-proton telescope is utilized for the measurements. The data is compared with macroscopic optical model potentials derived from proton scattering. In addition, comparisons with the microscopic optical model potentials, those of Jeukenne-Lejeune-Mahaux and Yamaguchi-Nagata-Matsuda, give a very good fit to the data.

Published
1994

38. A compact system with live converter for neutron spectrum measurements

Author

J. L. Ullmann, W. Caskey, E. L. Hjort, J. H. Osborne, D. R. Mayo, F. P. Brady, J. L. Romero, J. C. Kintner, and D. S. Sorenson

Subjects
Bonner sphere, Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Neutron stimulated emission computed tomography, Neutron scattering, Neutron temperature, Neutron time-of-flight scattering, Nuclear physics, Neutron cross section, Physics::Accelerator Physics, Neutron detection, Neutron, Nuclear Experiment, Instrumentation
Abstract

A “live” plastic scintillator converter has been added to our compact, neutron detector system. The latter employs a large-area, proton telescope, consisting of multiwire chambers, ΔE and E detectors to measure the energy and angle of recoil protons. The “live” converter provides an increase in count rate by a factor of 6 as well as some improvement in neutron energy resolution. Neutron scattering data for a 65 MeV neutron beam at CNL and for neutron energies from 60 to 240 MeV at LAMPF have been taken with this type of system.

Published
1994

39. Fragmentation of 1.2 GeV per nucleonLa139

Author

J. C. Young, F. P. Brady, J. L. Romero, H. J. Crawford, Peter J. Lindstrom, D. E. Greiner, U. Lynen, W. B. Christie, B. McEachern, H. Sann, G. P. Grim, and C. E. Tull

Subjects
Momentum, Physics, Nuclear reaction, Nuclear physics, Nuclear and High Energy Physics, Fragmentation (mass spectrometry), Nuclear Theory, Transverse momentum, Charge density, Nuclear Experiment, Nucleon
Abstract

The fragmentation of 1.2 GeV per nucleon $^{139}\mathrm{La}$ nuclei has been studied. Total charge changing cross sections for H (${\mathrm{CH}}_{2}$-C), C, and Pb target nuclei, and elemental production cross sections for C and ${\mathrm{CH}}_{2}$ targets for 1\ensuremath{\le}\ensuremath{\Delta}Z\ensuremath{\le}30 have been measured. For heavy projectile fragments, the projected transverse momenta extracted are generally larger than predicted by models based on the internal momenta of nucleons in nuclei. Fits to the heavy fragment momentum distributions yield additional transverse momenta or ``bounce-off'' which range from \ensuremath{\simeq}500 to 1000 MeV/c.

Published
1993

40. The 54,56Fe(n, p)54,56Mn reactions at En = 97 MeV

Author

Nils Olsson, F. P. Brady, W. Unkelbach, A. Ringbom, H. Condé, P-U Renberg, Ane Håkansson, O. Jonsson, Leif Nilsson, R. Zorro, E. Ramström, T. Rönnqvist, S.Y. van der Werf, Gunnar Tibell, and Jan Blomgren

Subjects
Nuclear physics, Nuclear reaction, Physics, Nuclear and High Energy Physics, Supernova, Isotope, Scattering, Electron capture, Nuclear Theory, Atomic physics, Born approximation, Spectral line, Excitation
Abstract

Double-differential cross sections of the 54,56Fe(n, p) reactions have been measured at 97 MeV in the angular range 0–30° for excitation energies up to 40 MeV. The spectra have been decomposed into different multipolarities by a technique based on the use of sample angular distributions calculated within the distorted-wave Born approximation. From the identified Gamow-Teller strength, Sβ+ values were obtained for 54Fe and 56Fe. Comparisons with available shell-model calculations of the GT strength were made. The results are important for models of supernova explosions since electron-capture rates, which are proportional to Sβ+, in 1f2p-shell nuclei affect the dynamics of the star. At higher excitation energies, the spectra are dominated by L = 1 strength in broad distributions with a maximum at about 12 MeV. Microscopic calculations based on the random-phase approximation were performed and compared with the experimental data.

Published
1993

42. Pion correlations in 1.8AGeV Ar on KCl and La and 1.2AGeV Xe on La

Author

W. Christie, H. H. Wieman, T. Abbott, T. J. M. Symons, W. F. J. Mueller, Craig Tull, D. Keane, D. L. Olson, F. P. Brady, Y. M. Liu, J. L. Romero, S. Y. Fung, and D. R. Beavis

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Meson, Computer Science::Information Retrieval, Hadron, Elementary particle, Lambda, Nuclear physics, Momentum, Pion, Atomic physics, Nuclear Experiment, Boson
Abstract

Results are presented for pion interferometry measurements of 1.8{ital A} GeV Ar+KCl and Ar+La, and 1.2{ital A} GeV Xe + La at the Lawrence Berkeley Laboratory Heavy Ion Spectrometer System. The parameters {ital R}, {tau}, {lambda}, {ital R}{sub {perpendicular}}, and {ital R}{sub {parallel}} are presented for all three projectile-target combinations. The correlation between the extracted size of the pion source and the centrality of the collision is investigated as well as the freeze-out densities and the dependence of the source size on the mean momentum of the pion pairs. The experimental setup and analysis are discussed and comparisons made with the results of others. The phase space covered is at forward angles in the center-of-mass system.

Published
1992

43. Gamow-Teller and dipole strength distribution inCa40(n,p)40K reaction

Author

J. L. Ullmann, CT Rönnqvist, C. R. Howell, J. L. Romero, D. S. Sorenson, B. K. Park, Werner Tornow, J. Rapaport, F. P. Brady, and A. Ling

Subjects
Physics, Nuclear and High Energy Physics, Dipole, Distribution (mathematics), Resonance, Neutron source, Neutron, Atomic physics, Nuclear Experiment, Multipole expansion, Excitation, Energy (signal processing)
Abstract

Double differential cross-section angular distributions covering 0\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$\ensuremath{\le}40\ifmmode^\circ\else\textdegree\fi{} have been measured for the $^{40}\mathrm{Ca}$(n,p${)}^{40}$K charge exchange reaction. With the white neutron source at LAMPF-WNR, we were able to study not only the angular distribution but also the energy dependence of this charge exchange reaction covering simultaneously incident neutron energies between 60 and 260 MeV. The identification of Gamow-Teller (GT) transitions and L=1 dipole resonance was carried out using a multipole decomposition technique. The empirically deduced GT strength in the $^{40}\mathrm{Ca}$(n,p${)}^{40}$K reaction evaluated up to 15 MeV excitation energy is compared to theoretical values. We have used a simple one-particle--one-hole shell model calculation to study the excitation of the giant dipole resonance and the giant spin-dipole resonance, which are compared with empirical results.

Published
1992

44. Ground-state Gamow-Teller strength inNi64(n,p)64Co cross sections at 90–240 MeV

Author

J. L. Ullmann, Roger W. Finlay, A. Ling, J. Rapaport, F. P. Brady, C. R. Howell, J. L. Romero, R. C. Haight, Nicholas S. P. King, P. W. Lisowski, B. K. Park, X. Aslanoglou, D. S. Sorenson, and Werner Tornow

Subjects
Physics, Scattering cross-section, Nuclear reaction, Nuclear and High Energy Physics, Supernova, Absolute measurement, Nuclear Theory, Neutron, Atomic physics, Nuclear Experiment, Ground state, Unit (ring theory), Inelastic neutron scattering
Abstract

Cross sections have been measured for the reaction $^{64}\mathrm{Ni}$(n,p${)}^{64}$Co at laboratory angles between 0\ifmmode^\circ\else\textdegree\fi{} and 10\ifmmode^\circ\else\textdegree\fi{} for incident neutron energies from 90 to 240 MeV. The ground-state cross sections together with the ${\mathrm{\ensuremath{\beta}}}^{\mathrm{\ensuremath{-}}}$ decay ft value for the transition $^{64}\mathrm{Co}$(g.s.)${\ensuremath{\rightarrow}}^{64}$Ni(g.s.) are used to normalize the q=0 differential cross section in units of mb/sr per unit Gamow-Teller (GT) strength. This is the first absolute measurement of the A(n,p) unit cross section for a nucleus in the (fp) shell, and it may be used to calibrate the GT strength measured in other (n,p) reactions of similar mass nuclei. Since the (${\mathit{e}}^{\mathrm{\ensuremath{-}}}$,${\ensuremath{\nu}}_{\mathit{e}}$) channel involves the same nuclear matrix element as the (n,p) channel, knowledge of GT strength in these nuclei is important for supernova modeling codes which depend on knowledge of ${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ capture rates of (fp)-shell nuclei to determine parameters of stellar core collapse.

Published
1991

45. analyzing powers and differential cross sections at 32, 40, 50 and 52.5 MeV

Author

B.E. Bonner, A.L. Sagle, N.S.P. King, J. L. Romero, and F. P. Brady

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Proton, Cyclotron, Function (mathematics), law.invention, Nuclear physics, Cross section (physics), law, Atomic physics, Legendre polynomials, Beam (structure), Differential (mathematics)
Abstract

Measurements of the analyzing powers and differential cross sections for the 4He( p , d)3He reaction at 32, 40, 50 and 52.5 MeV have been carried out using a polarized proton beam from the 88 inch cyclotron at LBL. Legendre polynomial fits of the cross section and differential analyzing power (σA) as a function of energy have smoothly varying coefficients.

Published
1991

46. C12(n,p)12B reaction at 56, 60, and 65 MeV

Author

T.D. Ford, G.A. Needham, J. L. Drummond, F. P. Brady, C.M. Castaneda, D. J. Millener, D. S. Sorenson, B. McEachern, E. Hjort, N.S.P. King, and J. L. Romero

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Computer Science::Information Retrieval, Nuclear Theory, Isotopes of boron, Inelastic neutron scattering, Isospin, Giant resonance, Excited state, Born approximation, Atomic physics, Nuclear Experiment, Ground state
Abstract

The {sup 12}C({ital n},{ital p}){sup 12}B reaction has been studied at 60 and 65 MeV. Cross sections for the 1{sup +} ground state, the 2{sup +} first excited state at 0.95 MeV, an unresolved pair of 2{sup {minus}} and 4{sup {minus}} states at 4.4 MeV, and the analogs of the giant electric dipole and spin-dipole resonances around 7.7 MeV have been extracted and compared with previous data at 56 MeV and with microscopic distorted-wave Born approximation calculations. The shapes of angular distributions out to {ital q}{similar to}2 fm{sup {minus}1} are well reproduced by the calculations. A comparison of ({ital n},{ital p}), ({ital p},{ital n}), and ({ital p},{ital p}{prime}) cross sections near 60 MeV is made, and a value for {vert bar}{ital J}{sub {sigma}{tau}}{vert bar} (the volume integral of the central, spin-isospin part of the effective nucleon-nucleon interaction) is extracted. The magnitudes of cross sections for negative-parity states can be qualitatively understood when the loose binding of the {ital sd}-shell neutron in the final state and the effect of ground-state correlations on the dipole and spin-dipole strengths are taken into account.

Published
1991

47. The response of NaI(T1) to 30−60 MeV Z = 1 particles

Author

F. P. Brady, T.D. Ford, C.M. Castaneda, G.A. Needham, and J. L. Romero

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Deuterium, Inorganic crystals, Nuclear Theory, Detector, Physics::Accelerator Physics, Stopping power (particle radiation), Electron, Nuclear Experiment, Instrumentation
Abstract

Measurements are reported for the light output response on a NaI(T1) detector for protons, deuterons, and tritons with energies between 30 and 60 MeV. The stopping power region covered by this data overlaps previous data taken with electrons and protons. The new data around 60 MeV is interesting in that the light output is greater for deuterons (and tritons) than that for protons by the equivalent of ≈ 1 MeV. A comparison is made with the model of Murray and Meyer for light output response in inorganic crystals.

Published
1991

48. A facility for studies of neutron-induced reactions in the 50–200 MeV range

Author

Ane Håkansson, O. Jonsson, S. Hultqvist, Gunnar Tibell, Z. Szeflinski, A. Lindholm, M. Österlund, H. Condé, Jan Blomgren, Nils Olsson, Leif Nilsson, A. Brockstedt, R. Zorro, T. Rönnqvist, Peter Ekström, P-U Renberg, and F. P. Brady

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Spectrometer, Isovector, Nuclear Theory, Cyclotron, The Svedberg Laboratory, law.invention, Nuclear physics, Momentum, law, Neutron source, Neutron, Atomic physics, Nuclear Experiment, Instrumentation
Abstract

A facility for studies of neutron-induced reactions has been built at the upgraded Gustaf Werner cyclotron of the The Svedberg Laboratory, Uppsala, Sweden. Well-collimated, monoenergetic neutron beams are produced with a fairly long distance between the neutron source and the reaction target, to reduce background radiation. A magnetic spectrometer with large angular and momentum acceptance has been constructed to allow measurements of energy and angular distributions of light ions produced in neutron-induced reactions. Initially, studies will be undertaken of isovector monopole and Gamow-Teller resonances, induced by the (n,p) reaction in various nuclei. The performance is illustrated in a measurement of the doubly differential cross section of the 12C(n,p)12B reaction at 100 MeV.

Published
1990

49. Limitations of the distorted-wave impulse approximation in describing the energy dependence of theB10(n,p)Be10(g.s.) reaction

Author

R. C. Haight, C. Wuest, F. P. Brady, B. L. Clausen, R.A. Lindgren, Francesca Sammarruca, J. L. Romero, J. L. Ullmann, A. Ling, N. S. P. King, J. Rapaport, D. S. Sorenson, B.K. Park, E. J. Stephenson, and H. Baghaei

Subjects
Physics, Nuclear and High Energy Physics, Isovector, Momentum transfer, Elementary particle, Fermion, Isotopes of boron, Atomic physics, Isotopes of beryllium, Ground state, Lepton
Abstract

We report differential cross section measurements for the stretched transition from the {sup 10}B ground state (J{sup {pi}}=3{sup +}) to the {sup 10}Be ground state (J{sup {pi}}=0{sup +}) in the {sup 10}B(n,p){sup 10}Be (g.s.) reaction. These data were obtained over the energy range from 70 to 240 MeV, covering momentum transfer values from 0.6 to 2.5 fm{sup -1}. In this momentum transfer range, the isovector tensor effective interaction dominates the transition. Cross sections are compared to zero- and finite-range distorted wave impulse approximation calculations using modern free and density-dependent effective interactions and a transition density consistent with (e,e{sup '}) data. Good agreement is observed at energies above 120 MeV, but below this energy the cross sections are larger than the calculated values by more than 40%. The implications for DWIA calculations are discussed.

Published
2007

50. Measurement of neutron elastic scattering cross sections forC12,Ca40, andPb208at energies from65to225MeV

Author

Eric Bauge, D. S. Sorenson, J. H. Osborne, Arjan J. Koning, J. P. Delaroche, F. P. Brady, J. Rapaport, J. L. Ullmann, A. Ling, Nicholas S. P. King, J. L. Romero, Roger W. Finlay, and R. C. Haight

Subjects
Elastic scattering, Nuclear physics, Physics, Nuclear and High Energy Physics, Recoil, Carbon-12, Center (category theory), Neutron source, Neutron, Continuum (set theory), Nuclear Experiment, Kinetic energy
Abstract

Differential neutron elastic scattering cross sections for {sup 12}C, {sup 40}Ca, and {sup 208}Pb have been measured using the continuum neutron source at the Los Alamos Neutron Science Center. The mean incident neutron kinetic energies ranged from 65 to 225 MeV. The large acceptance drift chamber based (n,p) recoil detector telescope spanned a center-of-mass angular range of 7 deg. to 23 deg. The measured cross sections are compared with calculations obtained with different optical model potentials, including predictions based on microscopic theory and phenomenology.

Published
2004

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