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In this letter we report the first multi-differential measurement of correlated pion-proton pairs from 2 billion Au+Au collisions at sNN=2.42 GeV collected with HADES. In this energy regime the population of Δ(1232) resonances plays an important role in the way energy is distributed between intrinsic excitation energy and kinetic energy of the hadrons in the fireball. The triple differential d3N/dMπ±pdpTdy distributions of correlated π±p pairs have been determined by subtracting the πp combinatorial background using an iterative method. The invariant-mass distributions in the Δ(1232) mass region show strong deviations from a Breit-Wigner function with vacuum width and mass. The yield of correlated pion-proton pairs exhibits a complex isospin, rapidity and transverse-momentum dependence. In the invariant mass range 1.1

The probable projectile-target reactions to synthesize SHE, Z = 124, are identified as 58Fe+248-254Cf, 64Ni+240–248,250Cm, 70Zn+236–242,244Pu, 76Ge+232–236,238U, and 82Se+228–230,232Th leading to 304–312,314124. The ER excitation functions in xn (x = 1 to 5 for hot fusion and x = 1 to 2 for cold fusion) evaporation channel are calculated. The sums of all xn channel ER cross-sections are listed and predicted the most suitable combinations. It is observed that the compound nucleus having neutron number up to N = 184 have finite ER cross-section values and we conclude that the CN having neutron number N > 184 could not be synthesized in the laboratory in near future. We have also studied the alpha decay properties of the isotopes mentioned above using modified generalized liquid drop model (MGLDM). In our study, 4α chains were observed for 304124, 3α chains observed for 305124, 6α chains observed for 306–307124, and 5α chains observed for 308–312, 314124. [ABSTRACT FROM AUTHOR]

Abstract In this paper the technological aspects of the FAZIA array will be explored. After a productive commissioning phase, FAZIA blocks started to measure and give very useful data to explore the physics of Fermi energy heavy-ion reactions. This was possible thanks to many technical measures and innovations developed in the commissioning phase and tuned during the first experimental campaigns. This paper gives a detailed description of the present status of the FAZIA setup from the electronic and mechanical point of view, trying also to trace a path for new improvements and refinements of the apparatus. [ABSTRACT FROM AUTHOR]

The experimental verification of compound nucleus theory has successfully been performed for light ion induced reactions using proton and α -particle beams on different targets. However, such studies using the heavy ion beams are scarce due to the complex nature of heavy ion interaction process. The present work is an attempt to validate the Bohr's independent hypothesis using heavy ion beam of 18O beam on 159Tb targets and 12C on 165Ho targets, forming the same compound nucleus 177Ta. A channel wise analysis of cross section data for evaporation residues produced in 18O+159Tb and 12C+165Ho systems has been performed within the framework of statistical model code PACE4 and found to reasonably agree with the experimental data. Further, a comparison of reaction cross section data for the same evaporation residues produced in the two different systems has been found to follow Bohr's compound nucleus hypothesis at relatively higher excitation energies. However, at relatively lower excitation energies, a significant deviation in the measured cross section data of the same residues in the above mentioned systems have been observed and is attributed to the discrepancies in angular momentum values. Such discrepancies are well explained on the basis of input angular momentum involved in the reactions. [ABSTRACT FROM AUTHOR]

Within a Bayesian statistical framework using a Gaussian Process emulator for an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model simulator of heavy-ion reactions at intermediate energies, we infer from the HADES proton flow data the posterior probability distribution functions of in-medium baryon-baryon scattering cross section modification factor X with respect to free-space and the corresponding incompressibility K of nuclear matter as well as their correlation function. The mean value of X is found to be X = 1.32 − 0.40 + 0.28 at 68% confidence level assuming the nuclear incompressibility K will not exceed 400 MeV, providing circumstantial evidence for enhanced baryon-braryon scattering cross sections in hot and dense nuclear matter. [ABSTRACT FROM AUTHOR]

This review describes some key accomplishments of Günter Herrmann such as the establishment of the TRIGA Mark II research reactor at Mainz University, the identification of a large number of very neutron-rich fission products by fast, automated chemical separations, the study of their nuclear structure by spectroscopy with modern detection techniques, and the measurement of fission yields. After getting the nuclear chemistry group, the target laboratory, and the mass separator group established at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, a number of large international collaborations were organized exploring the mechanism of deeply inelastic multi-nucleon transfer reactions in collisions of Xe and U ions with U targets, Ca and U ions with Cm targets, and the search for superheavy elements with chemical separations after these bombardments. After the Chernobyl accident, together with members of the Institute of Physics, a powerful laser technique, the resonance ionization mass spectometry (RIMS) was established for the ultra-trace detection of actinides and long-lived fission products in environmental samples. RIMS was also applied to determine with high precision the first ionization potentials of actinides all the way up to einsteinium. In the late 1980ies, high interest arose in results obtained in fusion-evaporation reactions between light projectiles and heavy actinide targets investigating the chemical properties of transactinide elements (Z≥104). Remarkable was the observation, that their chemical properties deviated from those of their lighter homologs in the Periodic Table because their valence electrons are increasingly influenced by relativistic effects. These chemical results could be reproduced with relativistic quantum-chemical calculations. The present review is selecting and describing examples for fast chemical separations that were successful at the TRIGA Mainz and heavy-ion reaction studies at GSI Darmstadt. [ABSTRACT FROM AUTHOR]

Abstract The possibility to use a mini-phoswich detector to identify ions in the region of Z ∼ 10 is explored in the framework of the NUMEN project. The NUMEN program, aimed at the investigation of the nuclear matrix elements connected to the neutrinoless double beta decay by means of double charge exchange nuclear reactions, foresees very high fluencies, which prevent the use of standard silicon as stop detectors. The need of reasonable radiation hardness, together with a total energy resolution around 2% and a high granularity, makes scintillators possible candidates. Promising results are obtained using an array of plastic + inorganic phoswich scintillators readout by means of Silicon Photo Multipliers. [ABSTRACT FROM AUTHOR]

The decay of various compound nuclei formed via exotic neutron-rich 9 Li projectile is studied within the dynamical cluster-decay model (DCM). Following the earlier work of one of us (RKG) and collaborators (M. Kaur et al. (2015) [1] ), for an empirically fixed neck-length parameter Δ R e m p , the only parameter in the DCM, at a given incident laboratory energy E L a b , we are able to fit almost exactly the (total) fusion cross section σ f u s = ∑ x = 1 6 σ x n for 9 Li projectile on 208 Pb and other targets, with σ f u s depending strongly on the target mass of the most abundant isotope and its (magic) shell structure. This result shows the predictable nature of the DCM. The neck-length parameter Δ R e m p is fixed empirically for the decay of 217 At ⁎ formed in 9 Li +  208 Pb reaction at a fixed laboratory energy E L a b , and then the total fusion cross section σ f u s calculated for all other reactions using 9 Li as a projectile on different targets. Apparently, this procedure could be used to predict σ f u s for 9 Li-induced reactions where experimental data are not available. Furthermore, optimum choice of “cold” target-projectile combinations, forming “hot” compact configurations, are predicted for the synthesis of compound nucleus 217 At ⁎ with 8 Li +  209 Pb as one of the target-projectile combination, or another ( t , p ) combination 48 Ca +  169 Tb, with a doubly magic 48 Ca, as the best possibility. [ABSTRACT FROM AUTHOR]

Several elastic scattering angular distributions of C from target nuclei of A ≥ 39 are analyzed to extract theWoods-Saxon potential parameters with the fixed imaginary potential and Coulomb radius parameters. Using the best fitted diffuseness parameters, the correlations of the real part parameters with A + A and incident energy are revealed, and the systematic Woods-Saxon potential parameters are presented for nucleus-nucleus interaction. The proposed potential parameters can reproduce not only the elastic scattering angular distributions induced by C, but also many elastic scattering angular distributions induced by the projectiles other than C, thus providing important inputs for the study of nuclear reactions of heavy-ion systems. [ABSTRACT FROM AUTHOR]

Principal Component Analysis (PCA) via Singular Value Decomposition (SVD) of large datasets is an adaptive exploratory method to uncover natural patterns underlying the data. Several recent applications of the PCA-SVD to event-by-event single-particle azimuthal angle distribution matrices in ultra-relativistic heavy-ion collisions at RHIC-LHC energies indicate that the sine and cosine functions chosen a priori in the traditional Fourier analysis are naturally the most optimal basis for azimuthal flow studies according to the data itself. We perform PCA-SVD analyses of mid-central Au+Au collisions at E beam / A =1.23 GeV simulated using an isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model to address the following two questions: (1) if the principal components of the covariance matrix of nucleon azimuthal angle distributions in heavy-ion reactions around 1 GeV/nucleon are naturally sine and/or cosine functions and (2) what if any advantages the PCA-SVD may have over the traditional flow analysis using the Fourier expansion for studying the EOS of dense nuclear matter. We find that (1) in none of our analyses the principal components come out naturally as sine and/or cosine functions, (2) while both the eigenvectors and eigenvalues of the covariance matrix are appreciably EOS dependent, the PCA-SVD has no apparent advantage over the traditional Fourier analysis for studying the EOS of dense nuclear matter using the azimuthal collective flow in heavy-ion collisions. [ABSTRACT FROM AUTHOR]

Angular distributions of the 6Li(18O, 17O)7Li reaction were measured at Elab(18O) = 114 MeV for ground and excited states of exit nuclei. The data were analyzed within the coupled-reaction-channels method (CRC). The 6Li + 18O elastic and inelastic scattering channels as well as the simplest one- and two-step reactions were includ-ed in the coupled-reaction-channels scheme. In CRC calculations, the 6Li + 18O potential with parameters de-duced from the elastic scattering data, was used for the entrance reaction channel. The spectroscopic amplitudes of nucleons and clusters were calculated within the translational-invariant shell model. The 7Li + 17O potential parameters were deduced by fitting 6Li(18O, 17O)7Li reaction data. Isotopic differences of the 7Li + 17O, 7Li + 18O and 7Li + 16O potential, as well as the reaction mechanisms are studied.

We propose a new method for determination of temperature in spallation events. It is shown that temperature can be determined by applying the friction model of energy dissipation in participant-spectator model of a spallation process. First order estimate of temperature dependence of the participant zone on reaction Q-value is obtained from the Fermi gas model considerations. The heat diffusion process is also discussed.

The elastic scattering angular distribution of S on Mg at energies ranging from 65 to 110 MeV has been analyzed in the framework of the double folding (DF) model, using different effective nucleon-nucleon (NN) interactions based on the M3Y-Reid interaction. The Pauli correlation, zero-range, and finite-range exchange parts of the NN interactions are considered in the folding procedure to treat the single nucleon knock-on exchange term (SNKE) in the optical model. Successful reproduction of the data has been obtained with all the potentials considered in the present study. It is clear that the effect of Pauli correlation increases as the energy increases. Our calculations are insensitive to the strength of the imaginary potential used in the fit of the experimental data. We find also that the threshold anomaly is less pronounced in the S + Mg system. Our reaction cross sections are compared with the data, and the consistency between the real and imaginary volume integrals are checked by the dispersion relation. [ABSTRACT FROM AUTHOR]

Reaction-channel selected γ-ray spectroscopy is a key method in nuclear-structure studies far from the β-stability valley. Examples of such experiments on both sides of the valley are discussed and some of the typical detector setups are introduced: the HPGe arrays Gammasphere and Gretina and the available suite of associated particle detectors. The use of stable and radioactive ion beams is covered (to some extend) as well. A sort of historical perspective is presented stating that the emphasis in nuclear-structure studies has shifted from proton-rich to neutron-rich nuclei. [ABSTRACT FROM AUTHOR]

Within the quantum molecular dynamics (QMD) model, the dynamical octupole deformation is studied as a function of the central distance between the projectile and target in the approaching process of heavy-ion fusion reactions. The dependence of the maximum dynamical octupole deformations on the incident energies is also investigated. The dynamical octupole deformations can be observed during the approaching process, and the maximum dynamical octupole deformations become more significant with decreasing incident energies. The distributions of the proton and neutron centers in the projectile and target are also investigated, respectively. In the approaching process of heavy-ion fusion reactions, the separation between proton centers for two nuclei is larger than that between neutron centers because of the strong Coulomb potential. [ABSTRACT FROM AUTHOR]

The potential energy landscape for the synthesis is evaluated in the framework of the macroscopic-microscopic model. The fragmentation potential calculated in a configuration space characterized by five degrees of freedom associated to elongation, mass asymmetry, necking, and left/right deformations reveals the existence of several minima and some pronounced valleys. The valleys correspond mainly to the and quasifission channels, but also for some paths in the formation of the compound nuclear system. In this context, two different paths are obtained for the and entrance channels. The path leads to the formation of an isomeric minimum that decays by fission. The path evidences a larger probability for the formation of the compound nucleus. Therefore, the two distributions obtained for the associated quasifission processes are very different. [ABSTRACT FROM AUTHOR]

Presented is a universal description of the generalized fusion excitation function which indicates that the fusion reaction mechanism should vanish at center-of-mass energy per nucleon of about 13 MeV/nucleon independently of the specific heavy-ion reaction system. Placing reliance on this result and comforted by semiclassical transport model simulations we suggest that the proposed persistence of the incomplete fusion cross sections in the measurement of the 14 N induced reactions on heavy targets at beam energies between 100 A and 155 A MeV should be attributed to a geometrical participant-spectator-like reaction mechanism. [ABSTRACT FROM AUTHOR]

Heavy-ion collision simulations in various classical models are discussed. Heavy-ion reactions with spherical and deformed nuclei are simulated in a classical rigid-body dynamics (CRBD) model which takes into account the reorientation of the deformed projectile. It is found that the barrier parameters not only on the initial orientations of the deformed nucleus, but also on the collision energy and the moment of inertia of the deformed nucleus. Maximum reorientation effect occurs at near- and below-barrier energies for light deformed nuclei. Calculated fusion cross-sections for Mg + Pb reaction are compared with a static-barrier-penetration model (SBPM) calculation to see the effect of reorientation. Heavy-ion reactions are also simulated in a 3-stage classical molecular dynamics (3S-CMD) model in which the rigid-body constraints are relaxed when the two nuclei are close to the barrier thus, taking into account all the rotational and vibrational degrees of freedom in the same calculation. This model is extended to simulate heavy-ion reactions such asLi + Bi involving the weakly-bound projectile considered as a weakly-bound cluster of deuteron and He nuclei, thus, simulating a 3-body system in 3S-CMD model. All the essential features of breakup reactions, such as complete fusion, incomplete fusion, no-capture breakup and scattering are demonstrated. [ABSTRACT FROM AUTHOR]

The dynamical description of light, intermediate, heavy and superheavy nuclei formed in heavy-ion collisions is worked out using the dynamical cluster decay model (DCM), with reference to various effects such as deformation and orientation, temperature, angular momentum etc. Based on the quantum mechanical fragmentation theory (QMFT), DCM has been applied to understand the decay mechanism of a large number of nuclei formed in low-energy heavy-ion reactions. Various features related to the dynamics of competing decay modes of nuclear systems are explored by addressing the experimental data of a number of reactions in light, intermediate, heavy and superheavy mass regions. The DCM, being a non-statistical description for the decay of a compound nucleus, treats light particles (LPs) or equivalently evaporation residues (ERs), intermediate mass fragments (IMFs) and fission fragments on equal footing and hence, provides an alternative to the available statistical model approaches to address fusion-fission and related phenomena. [ABSTRACT FROM AUTHOR]

Abstract: The total fusion cross sections for the fusion of weakly bound 9Be on 27Al and 64Zn targets at near and above the barrier have been calculated using one dimensional barrier penetration model, taking scattering potential as the sum of Coulomb and proximity potential and the calculated values are compared with experimental data. For the purpose of comparison of the fusion of weakly bound projectiles and strongly bound projectiles, the total fusion cross sections for the reaction of tightly bound nucleus 16O on 64Zn have also been computed using a similar procedure. The calculated values of total fusion cross sections in all cases are compared with coupled channel calculations using the code CCFULL. The computed cross sections using Coulomb and proximity potential explain the fusion reactions well in both cases of weakly bound and strongly bound projectiles. Reduced reaction cross sections for the systems , and have also been described. [Copyright &y& Elsevier]

In the present work, fusion in heavy-ion collisions at energies near the Coulomb barrier to ≈ 33% above it has been studied for 14N + 175Lu system. The excitation functions of several reaction channels expected to be populated via complete fusion and/or the incomplete fusion of the projectile have been measured. The experimental excitation functions have been critically compared with the predictions of the statistical model code PACE4. The observed enhancement in the measured cross-sections with respect to the theoretical model code PACE4 predictions of all the reactions having α -particle(s) in the exit channel is reminiscent of the fact that incomplete fusion (ICF) is at work in populating these channels besides the complete fusion process. The relative probability of incomplete fusion in fusion dynamics, obtained in terms of incomplete fusion strength function F I C F has also been deduced. The observed behavior of F I C F suggests the increasing probability of ICF contributions with projectile energy. A strong and a dictating dependence of F I C F on projectile structure in terms of its Q α -value has been observed. The reduction procedures for the elimination of the geometric and the static effects suggest that the observed variation in the fusion data has a purely static origin i.e., a manifestation of different potential barriers and radii. The analysis done within the framework of universal fusion function indicates the fusion suppression of ≈ 5% for the 14N + 175Lu system. [ABSTRACT FROM AUTHOR]

Angular distributions of the 6Li(18O, 17O)7Li reaction were measured at Elab(18O) = 114 MeV for ground and excited states of exit nuclei. The data were analyzed within the coupled-reaction-channels method (CRC). The 6Li + 18O elastic and inelastic scattering channels as well as the simplest one- and two-step reactions were included in the coupledreaction- channels scheme. In CRC calculations, the 6Li + 18O potential with parameters deduced from the elastic scattering data, was used for the entrance reaction channel. The spectroscopic amplitudes of nucleons and clusters were calculated within the translational-invariant shell model. The 7Li + 17O potential parameters were deduced by fitting 6Li(18O, 17O)7Li reaction data. Isotopic differences of the 7Li + 17O, 7Li + 18O and 7Li + 16O potential, as well as the reaction mechanisms are studied [ABSTRACT FROM AUTHOR]

Abstract: The performance of the LAND neutron detector is studied. Using an event-mixing technique based on one-neutron data obtained in the S107 experiment at the GSI laboratory, we test the efficiency of various analytic tools used to determine the multiplicity and kinematic properties of detected neutrons. A new algorithm developed recently for recognizing neutron showers from spectator decays in the ALADIN experiment S254 is described in detail. Its performance is assessed in comparison with other methods. The properties of the observed neutron events are used to estimate the detection efficiency of LAND in this experiment. [Copyright &y& Elsevier]

In this paper, pre-equilibrium-emission has been investigated using particle-γ coincidence technique. Forward-to-backward yield ratios of different reaction products have been measured in 16O+169Tm system at 5.6 MeV/nucleon. Coincidences between prompt-γ-rays and charged particles emitted in various angular zones have been recorded to identify different reaction products. Several gating conditions have been projected onto the energy spectra to achieve the information about mode of reaction. Yield profiles of fusion/fusion-like channels identified from forward/backward/sideways particle (Z = 1, 2)-gated-spectra have been measured. High yield in forward cone has been observed from the experimentally measured forward-to-backward yield ratios. The enhanced forward cone yield has been attributed to the pre-equilibrium-emission. The maximum observed spin $(J^{\max}_{{\rm obs}})$ is found to be decreased with the number of proton emitted from the composite nucleus during the equilibrium and/or pre-equilibrium decay. [ABSTRACT FROM AUTHOR]

Electron-positron pair production data obtained by bombardment of emulsion detectors with either cosmic rays or projectiles with masses between 1 and 207 amu and kinetic energies between 18 GeV and 32 TeV have been reanalyzed using a consistent and conservative model of the background from electromagnetic pair conversion. The combined data yield a spectrum of putative neutral bosons decaying to e+e- pairs, with masses between 3 and 20 MeV/c2 and femtosecond lifetimes. The statistical significance against background for these "X-bosons" varies between 2σ and 8σ. The cross-section for direct production of X-bosons increases slowly with projectile energy, remaining over 1,000 times smaller than the pion production cross-section. [ABSTRACT FROM AUTHOR]

Results on bulk particle observables, from a hybrid approach to relativistic heavy-ion collisions, are presented over a wide range of beam energies from Elab = 2 - 160 A GeV. In this model a hydrodynamic phase is integrated into a hadronic transport model. This setup enables us to study the effect of the equation of state of hot and dense nuclear matter on different observables from heavy-ion collider experiments. In addition we present a study on density fluctuations at a phase transition in the framework of chiral fluid dynamics. [ABSTRACT FROM AUTHOR]

Abstract: The formation of hypernuclei in hadron-induced reactions and in heavy-ion collisions within a combination of a covariant transport model and a statistical fragmentation approach is investigated. We study the applicability and limitations of such a hybrid approach by comparing fragmentation data in heavy-ion collisions and proton-induced reactions. It turns out that the combined approach describes fairly well multiplicities and momentum spectra of fragments. We thus extend the model by including strangeness degrees of freedom in the fragmentation process, modeled by a phase-space coalescence method. We provide theoretical predictions on spectra and on inclusive cross sections of light hypernuclei for the future experiments on hypernuclear physics at the new GSI facility. [Copyright &y& Elsevier]