Particle identification for Z = 25 – 28 exotic nuclei from seastar experimental data

The particle identification (PID) method based on TOF-Bρ-ΔE measurement at RIKEN arediscussed, and its application for Z = 25 – 28 neutron-rich nuclei from SEASTAR (Shell Evolution And Search for Two-plus energy At RIBF) experimental data are presented. The results including the PID for beam and residual nucleus at BigRIPS and ZeroDegree, respectively, demonstrate that the reactions of interest are well separated. This ensures the precision in the data analysis later on.

COMPETITION BETWEEN LIGHT CLUSTER AND CONSTITUENT MULTINUCLEON EMISSION IN HEAVY-ION REACTIONS

Isoproduct competition. i.e. competition between cluster and multlnucleon emission leading to the same residual nucleus, emerges as a general, interesting and useful characteristic of nuclear reactions. Common properties and factors underlying the competition between pn and d as well as between p2n. dn and t evaporation are recognized and discussed. The application of the isoproduct-competition method in the delineation of the mechanisms involved in 7Li-lnduced reactions suggests that an additional mechanism, breakup-fusion, is involved even at very low energies. Finally, the competition associated with alpha emission In the 12C+16O reaction demonstrates a strong contribution from composite 4He emission which cannot be accounted far by either the systematica or standard statistical calculations.

Towards an effective model for (d,p) and (d,n) nucleon-transfer reactions to bound states for FLUKA

A general overview is presented of an effective model for the inclusion of (d,p) and (d,n) nucleon transfer direct reactions to bound states of the residual nucleus in the general-purpose radiation-transport code FLUKA. The model relies on the distorted-wave Born approximation, employing state-of-the-art subroutines for the numerical solution of the radial Schrödinger equation for the deuteron- and nucleon-nucleus wave-functions, as well as contemporary optical potential models for the latter two. A final variation of a handful of deuteron optical potential parameters provides the model with additional flexibility and enhances the agreement with experimental nucleon angular distributions in a considerable range of target nuclei and deuteron energies.

Isomeric cross section study of neutron induced reactions on Ge isotopes

Cross sections for the 70,76Ge(n,2n), 72,73Ge(n,p) and 72,74Ge(n, α) reactions have been measured at the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR Demokritos, using the activation technique. Neutron beams have been produced in the ~16-20 MeV energy region, by means of the 3H(d,n)4He reaction. The maximum flux has been determined to be of the order of 105 n/cm2 s, while the flux variation of the neutron beam was monitored by using a BF3 detector. The cross section has been deduced with respect to the 27Al(n, α)24Na and 93Nb(n,2n)92mNb reference reactions. The contaminations from reactions induced on neighboring Ge isotopes and leading to the same residual nucleus, have been taken into account. After the end of the irradiations, the activity induced by the neutron beams at the targets and reference foils, has been measured by HPGe detectors. Statistical model calculations using the EMPIRE code were performed on the data measured in this work as well as on data reported in literature.

Dispersion (asymptotic) theory of charged-particle transfer reactions and nuclear astrophysics

A new asymptotic theory is proposed for the peripheral transfer A(x, y)B reaction at low energies within the three-body (A, a and y) model by com bining the dispersion theory and DWBA, where x= y + a, B= A + a, and a is a transferred particle. The results of the analysis of the differential cross sections of the proton transfer 9Be(1°B, 9Be)1°B reaction at the 1°B projectile energy of 100 MeV populating the ground and excited states of the residual nucleus are presented. New estimates and their uncertainties are obtained for values of the asymptotic normalization coefficients for 9Be + p ^ 1°B and for the astrophys- ical S factors at stellar energy of the radiative capture 9Be(ρ, γ)1°B reaction.

Search for η-mesic nuclei in the SRC/BM@N experiment at the Nuclotron

The SRC/BM@N experiment was carried out in the 55th run of the Nuclotron using a liquid hydrogen target and a carbon beam with a kinetic energy of about 3.1 GeV/n. We propose to analyze the experimental data to search for a quasi-bound state of η-meson and nucleons in the reaction 12C+p → η(A-1)+X → π+p+(A-2). To achieve this goal, it is necessary to identify the residual nucleus (A-2) and the proton-pion pair formed from η-nuclei decay.

Enhanced monopole and dipole transitions in nuclei induced by α cluster structures

Enhancement of the monopole and dipole transitions in the low-lying state is discussed on the basis of the microscopic and macroscopic α cluster models. Theoretical calculation clearly demonstrates that the strength of the monopole and dipole transitions are strongly enhanced by the excitation in the relative motion of the α cluster and the residual nucleus. The transition strength induced by the α excitation appears as the discrete distribution, and its excitation energy is much lower than the excitation energy of the single nucleon excitation, which is expected from the naive mean field picture.

First glance at the tracking detectors data collected in the first BM@N SRC run

BM@N (Baryonic Matter at Nuclotron) is the first experiment at the accelerator complex of NICA-Nuclotron at JINR (Dubna). The aim of the experiment is to study collisions of relativistic ion beams of the kinetic energy from 1 to 4.5 AGeV with fixed targets. The last run started a new physics program of BM@N – Short Range Correlations (SRC) studies in light nuclei. The BM@N setup allows detecting of the residual nucleus for the first time. BM@N tracking detectors play a key role in the identification of the nucleus after hard scattering in inverse kinematics. We present the first results of the BM@N tracking detectors using the data collected in spring 2018.

European and Nuclear Disintegration

The horrific carnage on both sides of the conflict in the Great War of 1914–18 and the harsh postwar treaties transformed the face of Europe. Nuclear physics was also transformed, shortly before Rutherford left Manchester for Cambridge in early 1919, by his discovery of artificial nuclear disintegration, that alpha particles can disintegrate the nitrogen nucleus. He pursued his discovery at the Cavendish with his former Manchester student James Chadwick, who along with Charles Ellis and many others had been interned during the war in former racehorse stables in Ruhleben on the western outskirts of Berlin. Rutherford explained his discovery by assuming that an incident alpha particle expels a proton orbiting about a central core in the nitrogen nucleus, leaving a residual nucleus of lower atomic number.

Total and Differential Cross-Sections of 16O(γ,n)3Heα8Be0 Reaction

The 16O(g,n)3He3a-reaction was investigated with the aid of the diffusion camera placed in the magnetic field and irradiated with a beam of bremsstrahlung g-quanta with an endpoint energy of 150 MeV. In to the curve of excitation of the system of 2a‑particles the resonance, identified as the ground state of the nucleus 8Be, were observed. The partial channels of production of these state (16O(g,n)3Hea8Ве0) were isolated and kinematical parameters of g-quantum and neutron were calculated. The absolute total cross-section of the partial channels in the energy interval from the threshold up to 120 MeV was measured. It has been established that the reaction is of a successive type: at first, the neutron is knocked out, and the residual nucleus 15О is in the excited state. The differential cross sections 16O(g,n)3Hea8Ве0-reaction has been measured and the dependence of the asymmetry coefficient distributions of the g-quantum energy and the excitation energy of the compound nucleus at the first intermediate stage of decomposition. The results are explained by the quantum interaction with a quasideuterons model.