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Predictions of string and hydrodynamical models for 160 A GeV Pb on Pb reactions are discussed. Results of the quark-gluon string model suggest that complete stopping of nuclear matter is plausible at these energies. The results for baryon and energy densities in the two models are similar. These results support the continued application of the one-fluid dynamic model, particularly for later stages of the collisions.

Along with π0 and η mesons, a resonance structure in the invariant mass spectrum of two γ-quanta at M = 360 ± 7 ± 9 MeV is first observed in the reaction dC → γ + γ + X at momentum 2.75 GeV/c per nucleon. Preliminary estimates of its width and cross section are Γ = 49.2 ± 18.6 MeV and σγγ ~ 98 μb. The collected statistics is 2339 ± 340 events of 1.5·106 triggered interactions of a total number of ~ 1012 dC-interactions. This structure is not observed in pC collisions at the beam momentum 5.5 GeV/c. Possible mechanisms of this ABC-like effect are discussed.

An experimental study of nuclear reactions between Si-28 nuclei at 200 and 300 MeV/nucleon and hydrogen or deuterium target nuclei was performed at the CELSIUS storage ring in Uppsala, Sweden, to collect information about the reactions responsible for single-event effects in microelectronics. Inclusive data on Si-28 fragmentation, as well as data on correlations between recoils and spectator protons or alpha particles are compared to predictions from the Dubna cascade model and the Japan Atomic Energy Research Institute version of the quantum molecular dynamics model. The comparison shows satisfactory agreement for inclusive data except for He fragments where low-energy sub-barrier fragments and recoiling fragments with very large momenta are produced much more frequently than predicted. The yield of exclusive data are also severely underestimated by the models whereas the charge distributions of recoils in these correlations compare well. The observed enhancement in He emission, which may well be important for the description of single-event effects, is most likely to be attributed to alpha clustering in Si-28 nuclei.

The MARS code is under continuous development and has recently undergone substantial improvements that further increase its reliability and predictive power in numerous shielding, accelerator, detector and space applications. The major developments and new features of the MARS15 (2004) version described in this paper concern an extended list of elementary particles and arbitrary heavy ions and their interaction cross sections, inclusive and exclusive nuclear event generators, module for modelling particle electromagnetic interactions, enhanced geometry and histogramming options, improved MAD-MARS Beam Line Builder, enhanced graphical user interface and an MPI-based parallelisation of the code.

An improved version of the Cascade-Exciton Model (CEM) of nuclear reactions implemented in the codes CEM2k and the Los Alamos version of the Quark-Gluon String Model (LAQGSM) has been developed recently at LANL to describe reactions induced by particles and nuclei at energies up to hundreds of GeV/nucleon for a number of applications. We present several improvements to the intranuclear cascade models used in CEM2k and LAQGSM developed recently to better describe the physics of nuclear reactions. First, we incorporate the photonuclear mode from CEM2k into LAQGSM to allow it to describe photonuclear reactions, not previously modeled there. Then, we develop new approximations to describe more accurately experimental elementary energy and angular distributions of secondary particles from hadron-hadron and photon-hadron interactions using available data and approximations published by other authors. Finally, to consider reactions involving very highly excited nuclei (E* > 2-3 MeV/A), we have incorporated into CEM2k and LAQGSM the Statistical Multifragmentation Model (SMM), as a possible reaction mechanism occurring after the preequilibrium stage. A number of other refinements to our codes developed recently are also listed., 5 pages, pdf, 6 figures, to be published in Proc. Int. Conf. on Nuclear Data for Science & Technology (ND2004), Santa Fe, USA, Sept. 26 - Oct. 1, 2004

Isotopically enriched 129I (85% 129I and 15% 127I) targets were irradiated with a beam of 660‐MeV protons at the JINR DLNP Phasotron and cross sections of formation of 74 residual products were determined using the γ‐spectrometry method. Here, we analyze all these data using eleven different models, realized in eight codes: LAHET (Bertini, ISABEL, INCL+ABLA, and INCL+RAL options), CASCADE, CEM95, CEM2k, LAQGSM+GEM2, CEM2k+GEM2, LAQGSM+GEMINI, and CEM2k+GEMINI, in order to validate the tested models against the experimental data and to understand better the mechanisms for production of residual nuclei. We find that most of the codes are fairly reliable in predicting cross sections for nuclides not too far away in mass from the targets, but differ greatly in the deep spallation, fission, and fragmentation regions. None of the codes tested here except GEMINI allow fission of nuclei as light as iodine, therefore the best agreement with the 129I data, especially in the A=40–90 region, is shown by the codes CEM2k and LAQGSM when they are merged with GEMINI. We conclude that none of the codes tested here are able to reproduce well all these data and all of them need to be further improved; development of a better universal evaporation/fission model should be of a high priority.

The MARS code system, developed over 30 years, is a set of Monte Carlo programs for detailed simulation of hadronic and electromagnetic cascades in an arbitrary geometry of accelerator, detector and spacecraft components with particle energy ranging from a fraction of an electron volt up to 100 TeV. The new MARS15 (2004) version is described with an emphasis on modeling physics processes. This includes an extended list of elementary particles and arbitrary heavy ions, their interaction cross-sections, inclusive and exclusive nuclear event generators, photo-hadron production, correlated ionization energy loss and multiple Coulomb scattering, nuclide production and residual activation, and radiation damage (DPA). In particular, the details of a new model for leading baryon production and implementation of advanced versions of the Cascade-Exciton Model (CEM03), and the Los Alamos version of Quark-Gluon String Model (LAQGSM03) are given. The applications that are motivating these developments, needs for better nuclear data, and future physics improvements are described.

Double-differential cross sections of neutron production at angles from 0 to 110 degrees from many reactions induced by light and medium nuclei on targets from 12-C to 208-Pb, at several incident energies from 95 to 600 MeV/A have been measured recently at the Institute of Physical and Chemical Research (RIKEN) Ring Cyclotron in Japan and at the Heavy-Ion Medical Accelerator of the National Institute of Radiological Science in Chiba, Japan using the time-of-flight technique. We have analyzed all these new measurements using the Quantum Molecular Dynamics (QMD) model, the Oak Ridge intranuclear cascade model HIC, the ISABEL intranuclear cascade model from LAHET, and the Los Alamos version of the Quark-Gluon String Model code LAQGSM03. On the whole, all four models used here describe reasonably well most of the measured neutron spectra, although different models agree differently with data from specific reactions and some serious discrepances are observed for some reactions. We present here some illustrative results from our study, discuss possible reasons for some of the observed discrepancies and try to outline ways to further improve the tested codes in order to address these problems., Comment: 5 pages, pdf, 3 figures, to be published in Proc. Int. Conf. on Nuclear Data for Sciience & Technology (ND2004), Santa Fe, USA, Sept. 26 - Oct. 1, 2004

We measure cross sections for residual nuclide formation in the mass range 6 < A < 97 caused by bombardment with protons and deuterons of 3.65 GeV/nucleon energy of enriched tin isotopes (112-Sn, 118-Sn, 120-Sn, 124-Sn). The experimental data are compared with calculations by the codes FLUKA, LAHET, CEM03, and LAQGSM03. Scaling behavior is observed for the whole mass region of residual nuclei, showing a possible multifragmentation mechanism for the formation of light products (6 < A < 31). Our analysis of the isoscaling dependence also shows a possible contribution of multifragmentation to the production of heavier nuclides, in the mass region 39 < A < 81., 16 pages, LaTeX, 6 figures, 6 tables, submitted to Yadernaya Fizika (Physics of Atimoc Nuclei)

An improved version of the Cascade-Exciton Model (CEM) of nuclear reactions contained in the code CEM2k and the Los Alamos version of the Quark-Gluon String Model (LAQGSM) are merged with the well-known sequential-binary-decay model GEMINI by Charity. We present some results on proton-induced fragmentation, fission-product yields and on particle spectra predicted by these extended versions of CEM2k and LAQGSM. We show that merging CEM2k and LAQGSM with GEMINI allows us to describe many fission and fragmentation reactions in addition to the spallation and evaporation reactions which are already described well by these codes. Nevertheless, the current version of GEMINI we use does not provide a completely satisfactory description of some complex-particle spectra, fragment emission, and spallation yields for some reactions, and is not yet a universal tool for applications. Our results show that GEMINI contains a powerful model to describe evaporation/fission/fragmentation reactions and often provides better results when compared to other models, especially for emission of heavy fragments from reactions on medium-heavy nuclei (where most other models simply fail), but it must be further extended and improved in order to properly describe arbitrary reactions., Revised version of an ND2004 contribution (2004, Santa Fe, USA): minor revision of the text, Fig. 5 revised, references updated. We thank Dr. Claude Volant for noticing that the stated values of the fission delay time used in GEMINI were in error for several reactions in the earlier version of this paper

Thin natural uranium targets were irradiated by a 660 MeV proton beam from the Phasotron accelerator at the Joint Institute for Nuclear Research in Dubna, Russia. Cross‐sections of the formation of residual nuclei natU(p,xpyn)ZARes are determined by methods of gamma spectroscopy. Until now, 43 long‐lived (T1/2 > 100 days) isotopes were observed and their cross‐sections determined. More than 350 intermediate‐lived (1 day < T1/2 < 100 days) and short‐lived (T1/2 < 1 day) isotopes have been identified in the γ‐spectra and many unanalyzed lines yet remain. Final results for 43 long‐lived isotopes and upper cross‐section limits for 27 long‐lived isotopes are presented in this paper and compared with results by five different models.

Thermodynamic limit is more than just: ‘the limit of the system when size tends to infinity’. This rough definition can be sufficient in the simplest cases, but precise definition of the thermodynamic limit involves subtle constraints in order to compare systems of various sizes N but in the similar thermodynamic state. We discuss in this paper how these constraints must be handled in the non-extensive thermostatistics, within the canonical ensemble. Role of the entropy index q on the proper definition of the thermodynamic limit, is emphasized. In particular, the only choice to get non-trivial thermodynamic limit is: N ( q −1)= constant . It can lead to a steady state different from the Boltzmann–Gibbs thermodynamic limit. We show that the hypothesis of non-extensivity of the entropy is generally not so crucial for the infinite systems, with the notable exception of the critical systems.

We discuss several new developments in the field of strange and heavy flavor physics in high energy heavy ion collisions. As shown by many recent theoretical works, heavy flavored particles give us a unique opportunity to study the properties of systems created in these collisions. Two in particular important aspects, the production of (multi) strange hypernuclei and the properties of heavy flavor mesons, are at the core of several future facilities and will be discussed in detail.

We apply the canonical quantum statistical model of nuclear multifragmentation generalized in the framework of recently proposed Tsallis non-extensive thermostatistics for the description of nuclear multifragmentation process. The test calculation in the system with A=197 nucleons show strong modification of the 'critical' behaviour associated with the nuclear liquid-gas phase transition for small deviations from the conventional Boltzmann-Gibbs statistical mechanics., 4 pages, 4 figures

The relative yields of high energy deuterons and tritons as compared to protons have been measured in $p+\mathrm{Kr},$ ${}^{16}\mathrm{O}+\mathrm{Kr}$ and ${}^{20}\mathrm{Ne}+\mathrm{Ar}$ reactions with a continuously varying beam energy up to $500A(400A) \mathrm{MeV}.$ Statistical (expanding) evaporation models are not able to reproduce these $d/p$ or $t/p$ ratios, which for high particle energy $(g30 \mathrm{MeV})$ increase smoothly with beam energy. Models that contain nucleon-nucleon scattering, like cascade or nuclear molecular dynamics models, can only reproduce the ratios if a final-state interaction is introduced via the coalescence prescription. The coalescence radius that best fit the data is rather constant over wide beam energy intervals. Entropy can, however, not be directly determined from these ratios.

The cascade-percolation model is proposed to interpret the experimentally observed incident energy dependence of mass yield slopes for intermediate mass fragments generated in inclusive relativistic 4 He+Au reactions. A mass moment correlation analysis is performed for the more sophisticated exclusive data.

Kurchatov Institute, Russian Research Center, 123182 Moscow, RussiaTwo major aspects of strange particle physics at the upcoming FAIRand NICA facilities and the RHIC low energy scan will be discussed. A newdistinct production mechanism for hypernuclei will be presented, namelythe production abundances for hypernuclei from Λ’s absorbed in the spec-tator matter in peripheral heavy ion collisions. As strangeness is not uni-formly distributed in the fireball of a heavy ion collision, the properties ofthe equation of state therefore depend on the local strangeness fraction.The same, inside neutron stars strangeness is not conserved and latticestudies on the properties of finite density QCD usually rely on an expan-sion of thermodynamic quantities at zero strange chemical potential, henceat non-zero strange-densities. We will therefore discuss recent investiga-tions on the EoS of strange-QCD and present results from an effective EoSof QCD that includes the correct asymptotic degrees of freedom and adeconfinement and chiral phase transition.

The entropy evolution in heavy ion collisions is investigated by means of a cascade model study. The method for calculating the entropy is based on a smoothing over the momentum space by introducing a local temperature field. It is shown that the resulting specific entropy is rather sensitive to the proper choice of the phase space subdivision at the disassembly stage of the collision. Compared to recent results for specific entropy values inferred from the composite particle yield of 4..pi.. measurements, it is found that the cascade calculations do not favor other model treatments, but as a trend we obtain smaller entropy values than following from conventional considerations within equilibrium statistics.

Average multiplicity of protons fromp, d, α andC interactions with carbon at 4.2 GeV/c/ N is shown to increase with the mass number of incident nucleus. ThisA dependence is stronger for fast protons than for the slow ones. Angular and momentum distributions are described by the Dubna Cascade Model. Some discrepancy is observed in the high momentum part of the distributions.

The connection between the fragment yield and the associated specific entropy of participant matter produced in the course of a relativistic heavy ion collision is studied within the cascade approach. The essential impact parameter dependence of the fragment yield indicates that the specific entropy increases with impact parameter and that the breakup density is the larger the more central the collision process is. The results show that the bulk equilibrium limit for the entropy production is not reached for such heavy systems as Nb+Nb at 400 MeV/nucleon and that the finite size effects and the dynamical freeze-out process are dominant factors in determining the cluster abundances.