406 research outputs found
Effects of momentum conservation on the analysis of anisotropic flow
No full textBorghini N, Dinh PM, Ollitrault JY, Poskanzer AM, Voloshin SA. Effects of momentum conservation on the analysis of anisotropic flow. Physical Review C. 2002;66(1): 014901.We present a general method for taking into account correlations due to momentum conservation in the analysis of anisotropic flow, either by using the two-particle correlation method or the standard flow-vector method. In the latter, the correlation between the particle and the flow vector is either corrected through a redefinition (shift) of the flow vector, or subtracted explicitly from the observed flow coefficient. In addition, momentum conservation contributes to the reaction plane resolution. Momentum conservation mostly affects the first harmonic in azimuthal distributions, i.e., directed flow. It also modifies higher harmonics, for instance, elliptic flow, when it is measured with respect to a first harmonic event plane such as the one determined with the standard transverse momentum method. Our method is illustrated by application to NA49 data on pion directed flow
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A history of central collisions at the Bevalac
No full textYou have heard a great deal about Plastic Ball results at this conference. There were talks on the first morning by Hans-Georg Ritter and Karl-Heinz Kampert on the Plastic Ball at Berkeley, there will be a talk next week by Rudi Schmidt on the Plastic Ball at CERN, and many other speakers have mentioned Plastic Ball results. The young students may think that when the new field of relativistic heavy ion physics opened up, an ideal detector was designed and built, data immediately analyzed, and results produced. The theme of my talk is to show that this is incorrect. The experiments proceeded in logical stages, one building upon the other, increasing in complexity and sophistication. The analysis techniques and the theory developed along with the experiments. If the more senior people in the audience easily remember this history of the development of the relativistic heavy ion field, they may spend their time during this talk thinking about what is happening now and what will happen in the future in the ultrarelativistic heavy ion field, where I believe history is repeating itself. 18 refs., 18 figs
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Central collisions of relativistic nuclei. [Cross sections, partial data analysis, yield 250 MeV/nucleon to 2. 1 GeV/nucleon]
No full textNew data for relativistic heavy ion collisions are presented for the emitted protons and pions, and for the average multiplicities and angular correlations of the charged particles. Comparisons with several different theoretical approaches are made including the nuclear firestreak model. It appears that there is a group of nucleons with randomized motion and high temperature. The stage is reached where one is beginning to look for effects due to the expansion of a compressed region. 16 references
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Nuclear Science Division, 1995--1996 annual report
No full textThis report describes the activities of the Nuclear Science Division (NSD) for the two-year period, January 1, 1995 to January 1, 1997. This was a time of major accomplishments for all research programs in the Division-many of which are highlighted in the reports of this document
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Relativistic heavy ion reactions
No full textThe present status of the study of central collisions of relativistic heavy ions is presented. The phenomenology is described, and evidence is presented for a source of nucleons from a central region caused by the overlapping densities of the target and projectile. Some of the current theoretical approaches are described including the nuclear fireball model. It appears that there is a quasi-equilibrated region at high temperature, but the signature for the expected effects of high density is not yet clear, and therefore, experimentally, the effects of high density have not been identified
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