795 research outputs found
Statistical Fluctuations of Electromagnetic Transition Intensities and Electromagnetic Moments in pf-Shell Nuclei
We study the fluctuation properties of electromagnetic
transition intensities and electromagnetic moments in nuclei within
the framework of the interacting shell model, using a realistic effective
interaction for
-shell nuclei with a Ni core. The distributions of the transition
intensities and of the electromagnetic moments are well described by the
Gaussian orthogonal ensemble of random matrices. In particular, the transition
intensity distributions follow a Porter-Thomas distribution. When diagonal
matrix elements (i.e., moments) are included in the analysis of transition
intensities, we find that the distributions remain Porter-Thomas except for the
isoscalar . The latter deviation is explained in terms of the structure of
the isoscalar operator.Comment: 11 pages, 4 figure
Analysis of nucleus-nucleus collisions at high energies and Random Matrix Theory
We propose a novel statistical approach to the analysis of experimental data
obtained in nucleus-nucleus collisions at high energies which borrows from
methods developed within the context of Random Matrix Theory. It is applied to
the detection of correlations in momentum distributions of emitted particles.
We find good agreement between the results obtained in this way and a standard
analysis based on the method of effective mass spectra and two-pair correlation
function often used in high energy physics. The method introduced here is free
from unwanted background contributions.Comment: 11 pages, 10 figure
Statistical Fluctuations of Electromagnetic Transition Intensities in pf-Shell Nuclei
We study the fluctuation properties of E2 and M1 transition intensities among
T=0,1 states of A = 60 nuclei in the framework of the interacting shell model,
using a realistic effective interaction for pf-shell nuclei with a Ni56 as a
core. It is found that the B(E2) distributions are well described by the
Gaussian orthogonal ensemble of random matrices (Porter-Thomas distribution)
independently of the isobaric quantum number T_z. However, the statistics of
the B(M1) transitions is sensitive to T_z: T_z=1 nuclei exhibit a Porter-Thomas
distribution, while a significant deviation from the GOE statistics is observed
for self-conjugate nuclei (T_z=0).Comment: 8 pages, latex, 3 figures (ps format
Azimuthal anisotropy and correlations in the hard scattering regime at RHIC
Azimuthal anisotropy () and two-particle angular correlations of high
charged hadrons have been measured in Au+Au collisions at
=130 GeV for transverse momenta up to 6 GeV/c, where hard
processes are expected to contribute significantly. The two-particle angular
correlations exhibit elliptic flow and a structure suggestive of fragmentation
of high partons. The monotonic rise of for GeV/c is
consistent with collective hydrodynamical flow calculations. At \pT>3 GeV/c a
saturation of is observed which persists up to GeV/c.Comment: As publishe
Azimuthal anisotropy of K0s and Lambda prduction at mid-rapidity from Au+Au collisions at root s = 130 GeV
We report STAR results on the azimuthal anisotropy parameter v2 for strange
particles K0S, L and Lbar at midrapidity in Au+Au collisions at sNN = 130 GeV
at RHIC. The value of v2 as a function of transverse momentum of the produced
particles pt and collision centrality is presented for both particles up to pt
3.0 GeV/c. A strong pt dependence in v2 is observed up to 2.0 GeV/c. The v2
measurement is compared with hydrodynamic model calculations. The physics
implications of the pt integrated v2 magnitude as a function of particle mass
are also discussed.Comment: 6 pages, 4 figures, by the STAR collaboratio
Azimuthal anisotropy of K0S and Lambda + Lambda -bar production at midrapidity from Au+Au collisions at sqrt[sNN]=130 GeV
We report STAR results on the azimuthal anisotropy parameter v2 for strange particles K0S, Lambda , and Lambda -bar at midrapidity in Au+Au collisions at sqrt[sNN]=130 GeV at the Relativistic Heavy Ion Collider. The value of v2 as a function of transverse momentum, pt, of the produced particle and collision centrality is presented for both particles up to pt~3.0 GeV/c. A strong pt dependence in v2 is observed up to 2.0 GeV/c. The v2 measurement is compared with hydrodynamic model calculations. The physics implications of the pt integrated v2 magnitude as a function of particle mass are also discussed.Alle Autoren: C. Adler, Z. Ahammed, C. Allgower, J. Amonett, B. D. Anderson, M. Anderson, G. S. Averichev, J. Balewski, O. Barannikova, L. S. Barnby, J. Baudot, S. Bekele, V. V. Belaga, R. Bellwied, J. Berger, H. Bichsel, A. Billmeier, L. C. Bland, C. O. Blyth, B. E. Bonner, A. Boucham, A. Brandin, A. Bravar, R. V. Cadman, H. Caines, M. Calderón de la Barca Sánchez, A. Cardenas, J. Carroll, J. Castillo, M. Castro, D. Cebra, P. Chaloupka, S. Chattopadhyay, Y. Chen, S. P. Chernenko, M. Cherney, A. Chikanian, B. Choi, W. Christie, J. P. Coffin, T. M. Cormier, J. G. Cramer, H. J. Crawford, W. S. Deng, A. A. Derevschikov, L. Didenko, T. Dietel, J. E. Draper, V. B. Dunin, J. C. Dunlop, V. Eckardt, L. G. Efimov, V. Emelianov, J. Engelage, G. Eppley, B. Erazmus, P. Fachini, V. Faine, K. Filimonov, E. Finch, Y. Fisyak, D. Flierl, K. J. Foley, J. Fu, C. A. Gagliardi, N. Gagunashvili, J. Gans, L. Gaudichet, M. Germain, F. Geurts, V. Ghazikhanian, O. Grachov, V. Grigoriev, M. Guedon, E. Gushin, T. J. Hallman, D. Hardtke, J. W. Harris, T. W. Henry, S. Heppelmann, T. Herston, B. Hippolyte, A. Hirsch, E. Hjort, G. W. Hoffmann, M. Horsley, H. Z. Huang, T. J. Humanic, G. Igo, A. Ishihara, Yu. I. Ivanshin, P. Jacobs, W. W. Jacobs, M. Janik, I. Johnson, P. G. Jones, E. G. Judd, M. Kaneta, M. Kaplan, D. Keane, J. Kiryluk, A. Kisiel, J. Klay, S. R. Klein, A. Klyachko, A. S. Konstantinov, M. Kopytine, L. Kotchenda, A. D. Kovalenko, M. Kramer, P. Kravtsov, K. Krueger, C. Kuhn, A. I. Kulikov, G. J. Kunde, C. L. Kunz, R. Kh. Kutuev, A. A. Kuznetsov, L. Lakehal-Ayat, M. A. C. Lamont, J. M. Landgraf, S. Lange, C. P. Lansdell, B. Lasiuk, F. Laue, A. Lebedev, R. Lednický, V. M. Leontiev, M. J. LeVine, Q. Li, S. J. Lindenbaum, M. A. Lisa, F. Liu, L. Liu, Z. Liu, Q. J. Liu, T. Ljubicic, W. J. Llope, G. LoCurto, H. Long, R. S. Longacre, M. Lopez-Noriega, W. A. Love, T. Ludlam, D. Lynn, J. Ma, R. Majka, S. Margetis, C. Markert, L. Martin, J. Marx, H. S. Matis, Yu. A. Matulenko, T. S. McShane, F. Meissner, Yu. Melnick, A. Meschanin, M. Messer, M. L. Miller, Z. Milosevich, N. G. Minaev, J. Mitchell, V. A. Moiseenko, C. F. Moore, V. Morozov, M. M. de Moura, M. G. Munhoz, J. M. Nelson, P. Nevski, V. A. Nikitin, L. V. Nogach, B. Norman, S. B. Nurushev, G. Odyniec, A. Ogawa, V. Okorokov, M. Oldenburg, D. Olson, G. Paic, S. U. Pandey, Y. Panebratsev, S. Y. Panitkin, A. I. Pavlinov, T. Pawlak, V. Perevoztchikov, W. Peryt, V. A Petrov, M. Planinic, J. Pluta, N. Porile, J. Porter, A. M. Poskanzer, E. Potrebenikova, D. Prindle, C. Pruneau, J. Putschke, G. Rai, G. Rakness, O. Ravel, R. L. Ray, S. V. Razin, D. Reichhold, J. G. Reid, F. Retiere, A. Ridiger, H. G. Ritter, J. B. Roberts, O. V. Rogachevski, J. L. Romero, A. Rose, C. Roy, V. Rykov, I. Sakrejda, S. Salur, J. Sandweiss, A. C. Saulys, I. Savin, J. Schambach, R. P. Scharenberg, N. Schmitz, L. S. Schroeder, A. Schüttauf, K. Schweda, J. Seger, D. Seliverstov, P. Seyboth, E. Shahaliev, K. E. Shestermanov, S. S. Shimanskii, V. S. Shvetcov, G. Skoro, N. Smirnov, R. Snellings, P. Sorensen, J. Sowinski, H. M. Spinka, B. Srivastava, E. J. Stephenson, R. Stock, A. Stolpovsky, M. Strikhanov, B. Stringfellow, C. Struck, A. A. P. Suaide, E. Sugarbaker, C. Suire, M. Šumbera, B. Surrow, T. J. M. Symons, A. Szanto de Toledo, P. Szarwas, A. Tai, J. Takahashi, A. H. Tang, J. H. Thomas, M. Thompson, V. Tikhomirov, M. Tokarev, M. B. Tonjes, T. A. Trainor, S. Trentalange, R. E. Tribble, V. Trofimov, O. Tsai, T. Ullrich, D. G. Underwood, G. Van Buren, A. M. VanderMolen, I. M. Vasilevski, A. N. Vasiliev, S. E. Vigdor, S. A. Voloshin, F. Wang, H. Ward, J. W. Watson, R. Wells, G. D. Westfall, C. Whitten, Jr., H. Wieman, R. Willson, S. W. Wissink, R. Witt, J. Wood, N. Xu, Z. Xu, A. E. Yakutin, E. Yamamoto, J. Yang, P. Yepes, V. I. Yurevich, Y. V. Zanevski, I. Zborovský, H. Zhang, W. M. Zhang, R. Zoulkarneev, and A. N. Zubarev (STAR Collaboration
Elliptic flow from two- and four-particle correlations in Au + Au collisions at sqrt{s_{NN}} = 130 GeV
Elliptic flow holds much promise for studying the early-time thermalization
attained in ultrarelativistic nuclear collisions. Flow measurements also
provide a means of distinguishing between hydrodynamic models and calculations
which approach the low density (dilute gas) limit. Among the effects that can
complicate the interpretation of elliptic flow measurements are azimuthal
correlations that are unrelated to the reaction plane (non-flow correlations).
Using data for Au + Au collisions at sqrt{s_{NN}} = 130 GeV from the STAR TPC,
it is found that four-particle correlation analyses can reliably separate flow
and non-flow correlation signals. The latter account for on average about 15%
of the observed second-harmonic azimuthal correlation, with the largest
relative contribution for the most peripheral and the most central collisions.
The results are also corrected for the effect of flow variations within
centrality bins. This effect is negligible for all but the most central bin,
where the correction to the elliptic flow is about a factor of two. A simple
new method for two-particle flow analysis based on scalar products is
described. An analysis based on the distribution of the magnitude of the flow
vector is also described.Comment: minor text change
Disappearance of back-to-back high hadron correlations in central Au+Au collisions at = 200 GeV
Azimuthal correlations for large transverse momentum charged hadrons have
been measured over a wide pseudo-rapidity range and full azimuth in Au+Au and
p+p collisions at = 200 GeV. The small-angle correlations
observed in p+p collisions and at all centralities of Au+Au collisions are
characteristic of hard-scattering processes already observed in elementary
collisions. A strong back-to-back correlation exists for p+p and peripheral Au
+ Au. In contrast, the back-to-back correlations are reduced considerably in
the most central Au+Au collisions, indicating substantial interaction as the
hard-scattered partons or their fragmentation products traverse the medium.Comment: submitted to Phys. Rev. Let
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