Production of energetic particles in heavy-ion collisions

Cassing, W.; Metag, V.; Mosel, U.; Niita, Koji

doi:10.1016/0370-1573(90)90164-w

Cited by 539 publications

(513 citation statements)

References 196 publications

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“…In most theoretical studies of the kaon production in heavy ion collisions by either the Vlasov-Uehling-Uhlenbeck approach (VUU) [4], or by "quantum" molecular dynamics (QMD) [5,6], however, the kaon elementary production cross sections in free space parametrized by J. Randrup and C. M. Ko [12] for B 1 B 2 → B 3 Y K, and by J. Cugnon and R. M. Lombard [13] for πN → Y K are widely used. Here B stands for either the nucleon or the ∆(1232), Y stands for either the Σ or the Λ, respectively.…”

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confidence: 99%

The role of the Δ (1920) resonance for kaon production in heavy ion collisions

1994

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The long mean free path of K + mesons in nuclear matter makes this particle a suitable messenger for the dynamics of nucleus-nucleus reactions at intermediate energies (100 MeV to 3 GeV per nucleon). A prerequisite for this is the knowledge of the elementary production cross sections πN → ΣK. Here these cross sections are studied for the first time with the explicite inclusion of the rel (1 − ) vector meson exchange is included. It is shown that the total cross sections for different channels of the πN → ΣK reactions, i.e. π + p → Σ + K + , π − p → Σ − K + , π + n → Σ 0 K + (π − p → Σ − K + ) and π 0 p → Σ 0 K + differ not only by absolute values but also by their energy dependence. This shape differences are due to the mixture of the isospin I = 3/2 ∆(1920) with isospin I = 1/2 nucleon resonances. However, this I = 3/2 resonance does not give a contribution to the πN → ΛK reactions. So the shapes of the total cross sections πN → ΛK for different isospin projections are the same. In spite of this, such cross sections averaged over different isospin projections in the same multiplet are often used for studies of kaon production in heavy-ion collisions. Here we give an explicit separate parametrization of the cross sections for each channel πN → ΣK, which are calculated in this work. The total cross section for π − p → Σ − K + which runs through different I = 3/2 and I = 1/2 resonances can be well reproduced by the present model. * Supported by DFG under contract No. Fa 67/14-1 † Supported by GSI under contract No. 06 TÜ 736 0 Because kaons (K + ) have a long mean free path inside the nucleus, one believes that they are good messengers to provide information about the high density and temperature phase of the heavy ion collisions [1,2]. Furthermore, they can be also sensitive probes for the nuclear equation of state (EOS) [3]. For these reasons, many studies of kaon production in heavy ion collisions have been performed both theoretically and experimentally [1]- [13].In most theoretical studies of the kaon production in heavy ion collisions by either the Vlasov-Uehling-Uhlenbeck approach (VUU) [4], or by "quantum" molecular dynamics (QMD) [5,6], however, the kaon elementary production cross sections in free space parametrized by J. Randrup and C. M. Ko [12] for B 1 B 2 → B 3 Y K, and by J. Cugnon and R. M. Lombard [13] for πN → Y K are widely used. Here B stands for either the nucleon or the ∆(1232), Y stands for either the Σ or the Λ, respectively. Although there exists a relatively long history for kaon production studies, not many investigations have been performed for the elementary process [14].On the other hand, due to recent high precision data, we have now rich and accurate informations on the baryon resonances, on quantum numbers, on decay modes, on decay rates and so on [15,16]. Thus, it is now adequate and necessary to incorporate these resonances in calculations of the elementary cross section for kaon production. There are some works which include such baryon resonances in kaon production stu...

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mentioning

confidence: 99%

The role of the Δ (1920) resonance for kaon production in heavy ion collisions

1994

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“…The values of the parameters used in the initialization procedure have been taken from ref. [13]. They reproduce ground-state properties and general nuclear stability with good accuracy.…”

Section: Numerical Solution Of the Buu Equationmentioning

confidence: 90%

“…This simplifying approximation can be justified by the fact that these graphs have their maximal contributions in different kinematical regions so that the product of these terms can be neglected. We then obtain the result 1 wi£tal = "3 (w(l) + w(2) + w(3)) , (12) where, for example, w(l) = L (W~(P2'PI'P3'P~,pj,pU + wt;(P2'PI'P3'P~,pj,p~)) , (13) p with L:p denotes the sum over all permutations of the indices i,j, k. Furthermore, w(l) represents the contribution for which the nucleon with momentum PI is the middle one in fig. 1, and w (2), and w(3) are defined correspondingly.…”

Section: U(p;)fu(p3)mentioning

confidence: 99%

“…The numerical problem of solving the BUU equation efficiently has been extensively discussed in the literature [7,13,14]. In order to establish the framework for describing how many-particle collisions are incorporated, we first review the main elements of the numerical realization of the model for the standard case when only the two-body collision term is considered.…”

Section: Numerical Solution Of the Buu Equationmentioning

confidence: 99%

“…In order to reduce the numerical noise due to the finite size of the sample, we use a gaussian smearing procedure to achieve smooth densities and reliable Pauli-blocking factors, as described in ref. [13]. Furthermore, to speed up the computations, only a subset of the systems are employed for the calculation of the spatial density p( 1').…”

Section: Numerical Solution Of the Buu Equationmentioning

confidence: 99%

See 2 more Smart Citations

N-body collisions in high-energy nuclear reactions

Batko¹,

Randrup²,

Vetter³

1992

Nuclear Physics A

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Reaction Dynamics of Heavy Ion Collisions Studied by Hard Photon Emission

Metag

1991

Annalen der Physik

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Dedicated to the 200th Anniversary of Annalen der Physik.-Abstract. Tlic role of photons 11s n probe of heavy ion reaction dynamics is discus..ed. Experimental dtrta on tlie systems lUO + \V and 92310 + **Mo illustrate that hard photons render a time differentid information on the evolution of heavy ion collisions ranging from protonneutron brc.rnsstralilung in the initid phase to thermal emission from highly excited reaction products in the 1;ut stage of the reaction. Meuured hard photon multiplicities provide in addition a ncw approach to determine the impact parameter of heavy ion collisions. A systematics of hard photon emission prohxbilities reveals the role of tlie nucleonic Permi motion in the collision zone. Prospects for future c*.upcriments focussing on photon m d neutrnl meson production a t relativistic b o m b d i n g energies i~r e outlined. tTntorsuchungcn dcr Reaktionsdynamik yon Schwarionenreaktionen uher dio Emission hochenergetischer Photoneri lnlinltsubersiclit. Die Bedeutung von Photonen ills Sonden fur die Reaktionsdynamik voiiSchwerionenstoBcn wird diskutiert. Experimentelle Daten zu den Systemen l 6 0 + W und g2Mo -+-9 2 & I~ xeigen, daB Photonen iiber Proton-Neutron Brcmsstrahlung ~u s der Anfangsphase bis zur thcrmisclien Emission aus hochangeregten Reaktionsprodukten in der Endphase der Reaktion Aussagen zum zeitlichcn Ablauf von SchwerionenstoBcn ermoglichen. Gemessene Photonenmultiplizitten bieten zusgtzlich ein neues Verfahren zur Bestimmung des StoBparametera in Schwerionenreaktionen. Eine Systematik der Photonenemissionswahrscheinlichkeiten verdeutlicht, daB aus den Photonendaten auf die Impulsverteilung der Nukleonen in der Reaktionszone geschloesen werden kann. Ab-schlieBend werden die Perspektiven fiir zukunftige Experimente und neue physikalische Fragestel-1 ungen bei relativistischen Schwerionenstohn dargelegt.

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Production of energetic particles in heavy-ion collisions

Cited by 539 publications

References 196 publications

The role of the Δ (1920) resonance for kaon production in heavy ion collisions

The role of the Δ (1920) resonance for kaon production in heavy ion collisions

N-body collisions in high-energy nuclear reactions

Reaction Dynamics of Heavy Ion Collisions Studied by Hard Photon Emission

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