Mass dependence of the disappearance of flow in nuclear collisions

Westfall, G. D.; Bauer, Wolfgang; Craig, Duncan Q.M.; Cronqvist, M.; Gaultieri, E.; Hannuschke, S.; Klakow, Dietrich; Li, T.; Reposeur, T.; Molen, A. M. Vander; Wilson, W.K.; Winfield, J. S.; Yee, J.; Yennello, S. J.; Lacey, R.; Elmaani, A.; Lauret, J.; Nadasen, A.; Norbeck, E.

doi:10.1103/physrevlett.71.1986

Cited by 199 publications

(145 citation statements)

References 17 publications

Supporting

Mentioning

133

Contrasting

Order By: Relevance

“…The results on the cross section reductions reported here are consistent with the conclusions deduced in Ref. [28] from the analysis of flow data.…”

Section: Probing the Nucleon-nucleon Collision Cross Sectionsupporting

confidence: 82%

Probing transport theories via two-proton source imaging

Verde¹,

Danielewicz²,

Brown³

et al. 2003

Phys. Rev. C

View full text Add to dashboard Cite

Imaging technique is applied to two-proton correlation functions to extract quantitative information about the space-time properties of the emitting source and about the fraction of protons that can be attributed to fast emission mechanisms. These new analysis techniques resolve important ambiguities that bedeviled prior comparisons between measured correlation functions and those calculated by transport theory. Quantitative comparisons to transport theory are presented here. The results of the present analysis differ from those reported previously for the same reaction systems. The shape of the two-proton emitting sources are strongly sensitive to the details about the in-medium nucleon-nucleon cross sections and their density dependence.Typeset using REVT E X 1 INTRODUCTION Transport theories have been extensively used to describe the main features of heavy ion collisions at intermediate energies [1][2][3][4]. Successful microscopic models have been based on the Boltzmann-Uehling-Uhlenbeck (BUU) equation, which describes the temporal evolution of the one-body phase-space density under the influence of the nuclear mean field and individual nucleon-nucleon collisions [1]. The importance of such models stems from the connections they provide between observables measured in nucleus-nucleus collisions and microscopic quantities like the nuclear mean fields and the in-medium cross section. Recently, this connection has been exploited to place constraints on the equation of state (EOS) of nuclear matter at densities of 2ρ 0 ≤ ρ ≤ 4ρ 0 , where ρ 0 is the nuclear saturation density [5]. Comparable constraints on the EOS at lower densities require a more detailed understanding of transport phenomena at intermediate energies where the delicate interplay of competing sources of pressure, such as collisions via the residual interaction, govern the collision dynamics [6].Two-proton correlation functions can provide an important test of transport theory [7][8][9], through their sensitivity to the space-time properties of nuclear reactions [10,9,12]. Initial applications of BUU transport theory to two-proton correlation functions at incident energies of E/A<100 MeV were successful and indicated a significant sensitivity of the calculated correlation functions to the in-medium cross section [7][8][9]. The application of such techniques to higher incident energies, however, revealed that there were significant problems in reconciling the stronger calculated correlation functions to the weaker measured ones [9]. These problems, discussed below, led to criticisms that BUU transport theory might be an inadequate theoretical tool for such studies, either due to the neglect of the many body correlations in the BUU approach [8] or due to the neglect of the long lived decays of unstable fragments emitted during a collision [9].In this paper, we largely resolve this issue by showing how more quantitative experimental analyses of two-proton correlations can provide information that can be quantitatively compared to BUU transport...

show abstract

“…The results on the cross section reductions reported here are consistent with the conclusions deduced in Ref. [28] from the analysis of flow data.…”

Section: Probing the Nucleon-nucleon Collision Cross Sectionsupporting

confidence: 82%

Probing transport theories via two-proton source imaging

Verde¹,

Danielewicz²,

Brown³

et al. 2003

Phys. Rev. C

View full text Add to dashboard Cite

show abstract

“…The K500 Superconducting Cyclotron at the Texas A&M University Cyclotron Institute was used to produce beams of 70 Zn, 64 Zn, and 64 Ni at 35 MeV/nucleon which were collided with 70 Zn (95%), 64 Zn (99.8%), and 64 Ni (98.0%) self-supporting targets, respectively. The reaction products were measured using the 4π NIMROD-ISiS array (Neutron Ion Multi-detector for Reaction Oriented Dynamics with the Indiana Silicon Sphere) [51].…”

Section: Experimental and Theoretical Detailsmentioning

confidence: 99%

Transverse collective flow and midrapidity emission of isotopically identified light charged particles

et al. 2011

Self Cite

View full text Add to dashboard Cite

The transverse flow and relative mid-rapidity yield of isotopically identified light charged particles (LCPs) Ni systems. A large enhancement of the mid-rapidity yield of the LCPs was observed relative to the yield near the projectile rapidity. In particular, this enhancement was increased for the more neutron-rich LCPs demonstrating a preference for the production of neutron-rich fragments in the mid-rapidity region. Additionally, the transverse flow of the LCPs was extracted which provides insight into the average movement of the particles in the mid-rapidity region. Isotopic and isobaric effects were observed in the transverse flow of the fragments. In both cases, the transverse flow was shown to decrease with an increasing neutron content in the fragments. A clear inverse relationship between the transverse flow and relative mid-rapidity yield is shown. The increased relative mid-rapidity emission produces a decreased transverse flow. The Stochastic Mean-Field model was used for comparison to the experimental data. The results showed that the model was able to reproduce the general isotopic and isobaric trends for the mid-rapidity emission and transverse flow. The sensitivity of these observables to the density dependence of the symmetry energy was explored. The results indicate that the transverse flow and mid-rapidity emission of the LCPs are sensitive to the denisty dependence of the symmetry energy.

show abstract

“…The attractive part of the mean field becomes more and more important with a decrease in energy. As a consequence even negative scattering angles are possible [6] which can be imagined as partial orbiting of the two nuclei [7]. At a certain incident energy, called the balance energy E bal , the attractive and repulsive forces which are responsible for the transverse flow in the reaction plane cancel each other, causing the disappearance of this particular flow characteristic.…”

Section: Introductionmentioning

confidence: 99%

“…Whereas it was shown for small impact parameters that the balance energy depends only weakly on the stiffness of the equation of state [8,9], a large sensitivity to the nucleonnucleon in-medium cross section was recognized [8,9,7]. The functional dependence of the balance energy on the system size can be approximately described by a power law:…”

Section: Introductionmentioning

confidence: 99%