No Arabic abstract
The investigation of the d, 3H and 3He spin structure has been performed at the RIKEN(Japan) accelerator research facility and VBLHEP(JINR) using both polarized and unpolarized deuteron beams. The experimental results on the analyzing powers studies in dp- elastic scattering, d(d,3H)p and d(d,3He)n reactions are presented. The vector and tensor analyzing powers for dp-elastic scattering at 880 and 2000 MeV are obtained at the Nuclotron(VBLHEP). The result on the analyzing powers Ay, Ayy of the deuteron at 2000 MeV are compared with relativistic multiple scattering model calculations. The data on the tensor analyzing powers for the d(d,3H)p and d(d,3He)n reactions obtained at Ed = 200 and 270 MeV demonstrate the sensitivity to the 3H, 3He and deuteron spin structure. The essential disagreements between the experimental results and the theoretical calculations within the one-nucleon exchange model framework are observed. The wide experimental program on the study of the polarization effects in dp- elastic scattering, dp-nonmesonic breakup, d(d,3He)n, d(d,3H)p and d(3He,4He)p reactions using internal and extracted beam at Nuclotron is discussed.
Fragmentation reactions induced on light target nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the latest Los Alamos Monte Carlo transport code MCNP6 and with its cascade-exciton model (CEM) and Los Alamos version of the quark-gluon string model (LAQGSM) event generators, version 03.03, used as stand-alone codes. Such reactions are involved in different applications, like cosmic-ray-induced single event upsets (SEUs), radiation protection, and cancer therapy with proton and ion beams, among others; therefore, it is important that MCNP6 simulates them as well as possible. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after INC. Both CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to He4 from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.
Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to 4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes
We investigate the Coulomb excitation of low-lying states of unstable nuclei in intermediate energy collisions ($E_{lab}sim10-500$ MeV/nucleon). It is shown that the cross sections for the $E1$ and $E2$ transitions are larger at lower energies, much
Directed flow of deuterons, tritons, $^3$He, and $^4$He is studied in Au+Au collisions at a beam momentum of about 10.8 $A$ GeV/c. Flow of all particles is analyzed as a function of transverse momentum for different centralities of the collision. The directed flow signal, $v_1(p_t)$, is found to increase with particle mass. This mass dependence is strongest in the projectile rapidity region.
The inclusive 12C(p,p) and exclusive 12C(p,pX) reactions have been studied with a beam energy of 156 MeV and for X = p and alpha. The study focuses on the (p,pX) reaction mechanism and on the structure of 12C just above the particle-emission threshold, 14 < E_x < 28 MeV. Cross sections were simultaneously measured for all three reactions. The exclusive data were analyzed by making multiple-peak fits of the spectra and by Legendre-polynomial fits of the angular correlations. Multiple-peak fits were also made of the inclusive spectra. The resultant cross sections were compared to theoretical calculations. An analysis of the results shows that this region of E_x consists predominantly of resonant excitations, in contradiction to the findings of previous analyses.