Nuclear recollisions in laser-assisted α\alpha decay

Laser-induced nuclear recollisions following $\alpha$ decay in the presence of an intense laser field are investigated theoretically. We show that while an intense optical laser does not influence notably the tunneling rate in $\alpha$ decay, it can completely change the $\alpha$ particle spectrum. For intensities of $10^{22}-10^{23}$ W/cm$^{2}$, the field is strong enough to induce recollisions between the emitted $\alpha$ particle and the daughter nucleus. The energy gained by the $\alpha$ particle in the field can reach 20 MeV and suffice to trigger several types of nuclear reactions on a femtosecond time scale. Similar conclusions can be drawn about laser-induced recollisions after proton emission. Prospects for the experimental realization of laser-induced nuclear recollisions are discussed.Comment: 5 pages, 3 figures; v2 extended the motivation and discussion about experimental feasibility; results unchange

Superdeformed and Triaxial States in Ca 42

Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in ^{42}Ca were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0_{2}^{+} has been obtained and the role of triaxiality in the A∼40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time