Search

Nuclear particle production from peripheral to central events is presented. N/Z gradient between projectile and target is studied using the fact that two reactions have the same projectile+target N/Z and so the same neutron to proton ratio for the combined system and the impact parameter size dependent geometrical overlap region. Data in the forward part of the centre of mass indicates that N/Z equilibration is achieved for impact parameters below 6 fm and a comparison with transport model SMF calculations is done. SMF results agree with the data in average and by using the fragment multiplicity difference between 136Xe+112Sn and 124Xe+124Sn systems it seems possible to characterize the density dependence of the symmetry energy. [ABSTRACT FROM AUTHOR]

Modeling of high energy hadronic and nuclear interactions by the QGSJET-II generator is discussed. Recent updates related to the treatment of nonlinear effects in the interaction dynamics and to the model calibration with new LHC data are described. A special attention is devoted to the predictions of the new model version for characteristics of extensive air showers initiated by high energy cosmic rays. In particular, an improved description of charge exchange processes in pion collisions is discussed and the respective enhancement of the shower muon content is analyzed. [ABSTRACT FROM AUTHOR]

Coincidence measurements of breakup of 6,7Li and 9Be incident on various high-Z targets have provided a complete picture of the physical mechanisms triggering breakup. The measurements identify those breakup processes that are fast enough (10-22) to affect fusion. The majority of these prompt breakup events are triggered by transfer of a neutron from 6Li, 9Be, and of a proton to 7Li. The dominance of breakup following transfer demonstrates that the reaction outcomes involving weakly bound nuclei depend not only on the properties of the two colliding nuclei, but also on the ground-state and excited state properties of their neighbours. This is a key insight for understanding and predicting reactions of weakly-bound nuclei near the limits of nuclear existence. [ABSTRACT FROM AUTHOR]

The adiabatic potential energy curves and the spectroscopic constants of the ground state and many excited states of 1Σ+ symmetry for the alkaline earth ion BeLi+ have been investigated. We have used an ab initio approach based on non-empirical pseudopotentials for the Be2+ and Li+ cores, parametrized l-dependent polarization potentials and full configuration interaction calculations. The ground state spectroscopic constants are in good agreement with the available theoretical results; whereas these spectroscopic properties for the excited states are presented for the first time. Moreover, numerous avoided crossings between electronic states of 1Σ+ symmety have been localised and analysed. They are related to the interaction between the electronic states and to the charge transfer process between the two ionic systems Be+Li and BeLi+. Furthermore, the permanent and transition dipole moments are determined for a wide interval of internuclear distances. The permanent dipole moments for the X(1)1Σ+ and 31Σ+ electronic states have shown a linear behavior, especially, at intermediate and large distances, while the transition dipole function between neighbor states have revealed many peaks located around the avoided crossing positions. This work extends our recent study on the alkaline earth BeLi2+ ion and represents the necessary initial step towards the charge transfer processes in collisions of ions with atoms. [ABSTRACT FROM AUTHOR]

In this talk we introduce the main features of a QCD-based model in which the coupling as is constrained by an infrared mass scale. We show recent applications of this model to hadron-hadron collisions, gap survival probability calculations, and soft gluon resummation techniques. These results indicate a smooth transition from nonperturbative to perturbative behaviour of the QCD. [ABSTRACT FROM AUTHOR]

Excitation functions have been measured for evaporation residues from compound nuclei formed in the interaction of 6He with 197Au and 206Pb. The transfer reactions leading to 194Au, 196Au and 198Au were also studied for the case of 6He + 197Au. The experiments were performed at the JINR accelerator complex for radioactive beams DRIBs, capable of providing 6He beams of about 10 AMeV maximum energy and an intensity of up to 2×107 pps. The stacked foil activation technique was used directly in the beam extracted from the cyclotron or in the focal plane of the magnetic spectrometer MSP-144. The identification of the reaction products was done by their radioactive γ- or α-decay. The fusion reactions with the evaporation of two neutrons were characterized by an increase in the cross section compared to statistical model calculations. The analysis of the data in the framework of the statistical model for the decay of excited nuclei when the sequential fusion of 6He was taken into account has shown good agreement between the experimental and the calculated values of the cross sections for the case of sub-Coulomb-barrier fusion in the 206Pb+6He reaction. At the Coulomb barrier unusually high cross section was measured for the production of 198Au, whereas only an upper limit was determined for the formation of 199Au. Possible mechanisms of formation and decay of transfer reaction products are discussed. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]