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1.
W.?NeubertEmail author A.S.?Botvina 《The European Physical Journal A - Hadrons and Nuclei》2003,17(4):559-571
Experimental data related to fragment production in central Au on Au collisions were analysed in the framework of a modified statistical model which considers cluster production both prior and at the equilibrated stage. The analysis provides limits to the number of nucleons and to the temperature of the equilibrated source. The rather moderate temperatures obtained from experimental double-yield ratios of d, t, 3He and 4He are in agreement with the model calculations. A phenomenological relation was established between the collective flow and the chemical temperature in these reactions. It is shown that dynamical mechanisms of fragment production, e.g. coalescence, dominate at high energies. It is demonstrated that coalescence may be consistent with chemical equilibrium between the produced fragments. The different meaning of chemical and kinetic temperatures is discussed.Received: 14 November 2002, Published online: 8 July 2003PACS:
25.70.Mn Projectile and target fragmentation - 25.70.Pq Multifragment emission and correlations - 25.75.-q Relativistic heavy-ion collisions 相似文献
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S.P. Avdeyev V.A. Karnaukhov W.D. Kuznetsov L.A. Petrov V.K. Rodionov A.S. Zubkevich H. Oeschler O.V. Bochkarev L.V. Chulkov E.A. Kuzmin A. Budzanovski W. Karcz M. Janicki E. Norbeck A.S. Botvina W.A. Friedman W. Nörenberg G. Papp 《The European Physical Journal A - Hadrons and Nuclei》1998,3(1):75-83
Multiple emission of intermediate-mass fragments has been studied for the collisions p + Au at 2.16, 3.6 and 8.1 GeV with
the FASA setup. The mean IMF multiplicities for events with at least one IMF are equal to 1.7, 1.9 and 2.1 (±0.2) respectively.
The multiplicity, charge distributions and kinetic energy spectra of IMF are described in the framework of a intranuclear
cascade model followed by the statistical multifragmentation model. However, between the two parts of the calculation the
excitation energies and the residual masses and charges are modified to take into account the losses during expansion. The
results support a scenario of true thermal multifragmentation of a hot and expanded target spectator.
Received: 15 December 1997 / Revised version: 24 April 1998 相似文献
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A. Botvina I. N. Mishustin M. Blann M. G. Mustafa G. Peilert H. Stöcker W. Greiner 《Zeitschrift für Physik A Hadrons and Nuclei》1993,345(3):297-303
Comparative analysis of three typical models of nuclear disintegration, the statistical multifragmentation model (SMM), the quantum statistical model (QSM) and a generalized evaporation model (GEM), is carried out. The thermodynamical properties of a decaying system as well as observable characteristics in heavy ion collisions predicted by the different models are discussed. It is shown that these models yield quite similar results for low charge yields at higher excitation energies (E/A>6 MeV per nucleon) and it is suggested that the coincidence measurements of the intermediate mass fragment multiplicity and the neutron and proton multiplicity (or alternatively, the total bound charge) may be very useful for deducing the decay mechanism. The GEM is shown to differ from the other models in predicting a high Z residue peak. 相似文献
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V. A. Karnaukhov H. Oeschler A. Budzanowski S. P. Avdeyev V. V. Kirakosyan V. K. Rodionov P. A. Rukoyatkin A. V. Simonenko W. Karcz I. Skwirczyńska E. A. Kuzmin E. Norbeck A. S. Botvina 《Physics of Atomic Nuclei》2006,69(7):1142-1148
Thermal multifragmentation of hot nuclei is interpreted as the nuclear liquid-fog phase transition inside the spinodal region. The exclusive data for p(8.1 GeV) + Au collisions are analyzed within the framework of the statistical model SMM. It is found that the partition of
hot nuclei is specified after expansion to a volume equal to V
t = (2.6 ± 0.3)V
0. The freeze-out volume is found to be twice as large: V
f = (5 ± 1)V
0. The similarity between multifragmentation and ordinary fission is discussed.
The text was submitted by the authors in English. 相似文献
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V. A. Karnaukhov S. P. Avdeyev H. Oeschler V. V. Kirakosyan P. A. Rukoyatkin A. Budzanowski W. Karcz E. Norbeck A. S. Botvina 《Physics of Particles and Nuclei Letters》2011,8(1):19-22
Nuclear multifragmentation in d (4.4 GeV) + Au collision was studied with the 4π setup FASA installed at the external beam of the Dubna Nuclotron. Data obtained
are analyzed within the statistical model of multifragmentation. It is found that the kinetic energy spectra of intermediate
mass fragments deviate from the predicted ones. It is explained by the collective flow caused by the thermal expansion of
fragmenting nucleus. 相似文献
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P. Napolitani K. -H. Schmidt P. Armbruster A. S. Botvina M. V. Ricciardi L. Tassan-Got F. Rejmund T. Enqvist 《Physics of Atomic Nuclei》2003,66(8):1471-1477
The high-resolution spectrometer FRS at GSI, Darmstadt, provides the full isotopic and kinematical identification of fragmentation residues in relativistic heavy-ion collisions. Recent measurements of the isotopic distribution of heavy projectile fragments led to a very surprising new physical finding: the residue production does not lose memory of the N/Z of the projectile ending up in a universal deexcitation corridor; an ordering of the residues in relation to the neutron excess of the projectile has been observed. These unexpected features can be interpreted as a new manifestation of multifragmentation. We have found that, at the last stage of the reaction, the temperature of the big clusters subjected to evaporation is limited to a universal value. The thermometer to measure this limiting temperature is the neutron excess of the residues. 相似文献
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