Collective flow, multi-fragment emission and azimuthal asymmetries in intermediate energy nucleus-nucleus collisions

Westfall, G. D.; Ogilvie, C. A.; Cebra, D.; Wilson, W.K.; Molen, A. Vander; Bauer, Wolfgang; Winfield, J. S.; Krofcheck, D.; Karn, J.; Howden, S.; Li, T.; Lacey, R.; Tyson, K.; Cronqvist, M.; Nadasen, A.

doi:10.1016/0375-9474(90)90622-s

Cited by 9 publications

(2 citation statements)

References 18 publications

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“…Nevertheless, these spurious effects average out and the mean flow vector lies approximately in the impact plane. However, the tilting angle ¢F associated with a particular system can deviate significantly from the ensemble average value [31]. In order to illustrate the magnitude of this effect, the calculated probability distributions of the tilting angle ¢F are shown in fig.…”

Section: Thermalization and Flow Anglesmentioning

confidence: 99%

N-body collisions in high-energy nuclear reactions

Batko¹,

Randrup²,

Vetter³

1992

Nuclear Physics A

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Section: Thermalization and Flow Anglesmentioning

confidence: 99%

N-body collisions in high-energy nuclear reactions

Batko¹,

Randrup²,

Vetter³

1992

Nuclear Physics A

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“…Consequently, the mid-rapidity nucleons are emitted preferential in the entrance-channel reaction plane. So far, such rotation-like mechanism of particle emission was discovered experimentally [12][13][14]. Moreover, this rotation-like mechanism shows not only in the coordinate space, but also in the momentum space.…”

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confidence: 99%

Rotation-like behavior as a function of projectile energy and target mass

Shen

Feng

et al. 1993

Z. Physik A - Hadrons and Nuclei

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Abstract. The azimuthal distributions produced in the intermediate energy 4~reactions are calculated via the nuclear transport theory. The rotational collective motion is observed from the mid-rapidity particles emission. In addition to the investigation on particle emission in the coordinate space, the momentum distributions of emitted particles as a function of azimuthal angle are also discussed. The azimuthal distributions are fitted by performing Legendre polynomial expansion to second order. By incorporating the fluctuation between the estimated and true reaction plane into our calculations, quantitative agreements with the data are obtained for 4~ reactions below 85 MeV/nucleon. It is found that the rotation-like behavior becomes stronger with the increasing of the impact parameter and weaker with the increasing of the projectile energy. For 4~ system at about 85 MeV/nucleon the rotation-like behavior almost vanishes and the mid-rapidity azimuthal distribution tends to be isotropic. For 35 MeV/nucleon 4~ reactions the rotation-like behavior becomes weaker and the out-of-plane enhancement of particle emission appears with the increasing of target mass. The possible origins of these target mass dependent azimuthal distributions at mid-rapidity are discussed. PACS: 25.70.PqA main goal of intermediate energy heavy ion collisions (HIC) is to investigate the dynamic mechanism and extract information about the nuclear equation of state (EOS). Various observables have been proposed in the past, including energetic particle productions, flow angles, in-plane collective flow, etc. Some models which attempt to calculate these observables can be found in recent review articles [1][2][3][4][5][6].In this work we examine the azimuthal distribution as a testing ground for the nuclear dynamics. Some experiments to measure such distributions for fission flagments, charged particles and neutrons have been performed at the both intermediate-I-7-14] and high-energy domain [-15-21]. At high energy, out-of-plane enhancement of particle emission at mid-rapidity has been discovered, so-called the squeeze-out effect. But up to now, it is not found for light reaction systems. At intermediate tenergy, m-plane enhancement of particle emission is dominant, and it is considered to have origins of such as in-plane collective flow and rotation-like behavior.The effect of the in-plane collective flow on the azimuthal distribution should result in peaking at +180 ~ at low rapidity (target rapidity region) and at 0 ~ at high rapidity (projectile rapidity region), and should vanish at midrapidity 9 So the azimuthal distribution at mid-rapidity is sensitive to the mechanism of particle emission 9 It was proved that there existed preferential emission with respect to the reaction plane on the side of target and projectile at mid-rapidity due to the rotation-like behavior at intermediate energy for some systems [12-14, 22, 23]. Although both the squeeze-out effect and the rotation-like behavior were discovered respectively at different energy d...

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