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Résumé |
1) The influence of a strong laser electromagnetic field on the alpha-decay
rate is ingestigated by using the Hennenberger frame of reference [1]
within adiabadic and static limits. The penetrability of the Coulomb barrier
becomes anisotropic for intensities corresponding to $D\sim1$, where $D$ is an
adimensional parameter proportional to the square root of the intensity.
As a consequence, we predict that two counters placed at zero and 90 degrees
will indicate different numbers.
2) Alpha clusters are born in nuclei at low densities, the wave function being
a Gaussian peaked on the nuclear surface and therefore corresponding to a local
pocket-like potential. The alpha-particle formation probability reaches the largest
value in the ”alpha-decay island” above $^{100}$Sn for N$\sim$Z nuclei [2] and therefore
the clusters can be easier detected. We show that the shape of the alpha-cluster
can be determined by exciting it to the first resonant state inside the pocket-like
potential, by using a quasi-monochromatic gamma-beam produced at the ELI-NP facility.
The position and width of this ”alpha-like pygmy” resonant state [3] can be predicted
by using the alpha-decay systematics to ground and excited states [4]. \\
[1] D.S. Delion and S. Ghinescu, Geiger-Nuttall law for nuclei in strong electromagnetic fields, Phys. Rev. Lett. 119, 202501 (2017).\newline
[2] V.V. Baran and D.S. Delion, Proton-neutron versus alpha-like correlations above $^{100}$Sn, Phys. Rev. C 94, 034319 (2016).\newline
[3] V.V. Baran and D.S. Delion, Alpha-like resonances in nuclei, J. Phys. G 45, 035106 (2018).\newline
[4] D.S. Delion, Universal decay rule for reduced widths, Phys. Rev. C 80, 024310 (2009).
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