Systematics of central heavy ion collisions in the regime

Reisdorf, W.; Andronic, A.; Averbeck, R.; Benabderrahmane, M. L.; Hartmann, O.; Herrmann, N.; Hildenbrand, K. D.; Kang, T. I.; Kim, Y. J.; Kiš, M.; Koczoń, P.; Kress, T.; Leifels, Y.; Merschmeyer, M.; Piasecki, Krzysztof; Schüttauf, A.; Stockmeier, M.; Barret, V.; Basrak, Z.; Bastid, N.; Čaplar, R.; Crochet, P.; Dupieux, P.; Dželalija, M.; Fodor, Z.; Gasik, P.; Grishkin, Y.; Hong, B.; Kecskeméti, J.; Kirejczyk, M.; Korolija, M.; Kötte, R.; Lebedev, A.; Lopez, X.; Matulewicz, T.; Neubert, W.; Petrovici, M.; Rami, F.; Ryu, M. S.; Seres, Z.; Sikora, B.; Sim, K. S.; Simion, V.; Siwek‐Wilczyńska, K.; Smolyankin, V.; Stoicea, G.; Tymiński, Z.; Wiśiewski, K.; Wohlfarth, D.; Zhang, Xiao; Xu, H. S.; Yushmanov, I. E.; Zhilin, A.

doi:10.1016/j.nuclphysa.2010.09.008

Cited by 163 publications

(182 citation statements)

References 80 publications

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“…Furthermore, by using the newly updated ultrarelativistic quantum molecular dynamics (UrQMD) model in which the Skyrme potential energy density functional is introduced, the recently published flow data [35,36] of the FOPI Collaboration for light charged particles (protons, 2 H, 3 H, 3 He, and 4 He) can be reproduced quite well [37]. An advantage of the UrQMD update is that the stiffness of the symmetry energy can be more consistently selected within a broad range by simply changing Skyrme interactions, rather than by varying the exponent γ in the potential term of the symmetry energy which, in addition, cannot be used to express a very soft symmetry energy [38].…”

Section: Introductionmentioning

confidence: 99%

Constraining the high-density nuclear symmetry energy with the transverse-momentum-dependent elliptic flow

Wang

Guo

et al. 2014

Phys. Rev. C

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Within the newly updated version of the ultrarelativistic quantum molecular dynamics (UrQMD) model, the transverse-velocity dependence of the elliptic flow of free nucleons from 197 Au+ 197 Au collisions at the incident energy 400 MeV/nucleon is studied within different windows of the normalized c.m. rapidity y 0 . It is found that the elliptic flow difference v n 2 -v p 2 and ratio v n 2 /v p 2 of neutrons versus protons are sensitive to the density dependence of the symmetry energy, especially the ratio v n 2 /v p 2 at small transverse velocity in the intermediate rapidity intervals 0.4 < |y 0 | < 0.6. By comparing either transverse-momentum dependent or integrated FOPI/LAND elliptic flow data of nucleons and hydrogen isotopes with calculations using various Skyrme interactions, all exhibiting similar values of isoscalar incompressibility but very different density dependences of the symmetry energy, a moderately soft to linear symmetry energy is extracted, in good agreement with previous UrQMD or Tübingen QMD model calculations but contrasting results obtained with π − /π + yield ratios available in the literature.

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Section: Introductionmentioning

confidence: 99%

Constraining the high-density nuclear symmetry energy with the transverse-momentum-dependent elliptic flow

Wang

Guo

et al. 2014

Phys. Rev. C

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“…For the case of kinetic energy spectra a conservative value for this upper limit must not be significantly larger than the kinetic energy of pions in pionic atoms, limiting it to values as low as [20][21][22][23][24][25][26][27][28][29][30] MeV. This ensures that uncertainties in the energy dependent part of the pion potential are largely removed.…”

Section: Constraining the Symmetry Energymentioning

confidence: 99%

“…II. The impact of this quantity on multiplicities, multiplicity spectra, and average p T values of pions is studied in detail, and, where available, a comparison with experimental FOPI data [20][21][22] is presented. Additionally, the impact of poorer known model parameters is also investigated, followed by a presentation of the extracted constraints for SE (Sec.…”

Section: Introductionmentioning

confidence: 99%

Constraining the density dependence of the symmetry energy using the multiplicity and average pT ratios of charged pions

Cozma

2017

Phys. Rev. C

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The charged pion multiplicity ratio in intermediate energy heavy-ion collisions, a probe of the density dependence of symmetry energy above the saturation point, has been proven in a previous study to be extremely sensitive to the strength of the isovector ∆(1232) potential in nuclear matter. As there is no knowledge, either from theory or experiment, about the magnitude of this quantity, the extraction of constraints on the slope of the symmetry energy at saturation by using exclusively the mentioned observable is hindered at present. It is shown that, by including the ratio of average pT of charged pions pin the list of fitted observables, the noted problem can be circumvented. A realistic description of this observable requires accounting for the interaction of pions with the dense nuclear matter environment by the incorporation of the so called S-wave and P -wave pion optical potentials. This is performed within the framework of a quantum molecular dynamics transport model that enforces the conservation of the total energy of the system. It is shown that constraints on the slope of the symmetry energy at saturation density and the strength of the ∆(1232) potential can be simultaneously extracted. A symmetry energy with a value of the slope parameter L > 50 MeV is favored, at 1σ confidence level, from a comparison with published FOPI experimental data. A precise constraint will require experimental data more accurate than presently available, particularly for the charged pion multiplicity ratio, and better knowledge of the density and momentum dependence of the pion potential for the whole range of these two variables probed in intermediate energy heavy-ion collisions.

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“…Typically, one million thermal K * (892) 0 's were generated with the fireball option (temperature of 90 MeV) of the event generator Pluto [27]. The choice of the temperature parameter follows from systematics of central heavy ion collisions in the 1 A GeV regime [28] and from the kinetic temperatures derived from the spectra of various hadrons carrying strangeness of comparable masses which are produced in Ar + KCl collisions at 1.76 A GeV [20,22]. A priori, neither a certain deviation of the spectral shape parameter from this value nor some anisotropy in the phasespace distribution of the K * 0 mesons can be excluded.…”

Section: Analysis Of Simulation Datamentioning

confidence: 99%

Deep sub-threshold K*(892)0 production in collisions of Ar + KCl at 1.76 A GeV

Agakishiev¹,

Bałanda²,

Bassini³

et al. 2013

Eur. Phys. J. A

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Abstract.Results on the deep sub-threshold production of the short-lived hadronic resonance K * (892) 0 are reported for collisions of Ar + KCl at 1.76 A GeV beam energy, studied with the High Acceptance DiElectron Spectrometer (HADES) at SIS18/GSI. The K * (892) 0 production probability per central collision of P K * 0 = (4.4 ± 1.1 ± 0.5) × 10 −4 and the K−2 are determined at the lowest energy so far (i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, √ sNN − √ s thr = −340 MeV). The K * 0 /K 0 ratio is compared with results of other experiments and with the predictions of the UrQMD transport approach and of the statistical hadronization model. The experimental K * 0 yield and the K * 0 /K 0 ratio are overestimated by the transport model by factors of about five and two, respectively. In a chemically equilibrated medium the ratio corresponds to a temperature of the thermalized system being systematically lower than the value determined by the yields of the stable and long-lived hadrons produced in Ar + KCl collisions. From the present measurement, we conclude that sub-threshold K * production either cannot be considered to proceed in a system being in thermal equilibrium or these short-lived resonances appear undersaturated, for example as a result of the rescattering of the decay particles in the ambient hadronic medium.

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Systematics of central heavy ion collisions in the regime

Cited by 163 publications

References 80 publications

Constraining the high-density nuclear symmetry energy with the transverse-momentum-dependent elliptic flow

Constraining the high-density nuclear symmetry energy with the transverse-momentum-dependent elliptic flow

Constraining the density dependence of the symmetry energy using the multiplicity and average pT ratios of charged pions

Deep sub-threshold K*(892)0 production in collisions of Ar + KCl at 1.76 A GeV

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