40Mg and the Kerman problem in the continuum
A. O. Macchiavelli - Lawrence Berkeley National Laboratory
Vendredi 06/09/2019, 11:00-12:00
Bat 703, p 135 salle visio-conférence, CEA Saclay, Orme des Merisiers


The effect of weak binding on nuclear structure, decay, and reactions is an open question in nuclear physics. On the neutron-rich side of stability, as the neutron separation energy approaches zero, weakly-bound neutrons in the single-particle levels at the Fermi surface approach the edge of the nuclear potential and may move outside the core of well-bound nucleons, and possibly couple to unbound continuum states. The nature of this transition from a “closed” to an “open” quantum system [1], where binding is dominated by correlations rather than the mean field, has only just begun to be explored, and our understanding of weak-binding effects and coupling to the continuum is, in many ways, nascent.

The first spectroscopic study of the near drip-line Nucleus 40Mg [2], revealed two γ-ray transitions that suggest an excitation spectrum with unexpected properties as compared to both the systematics along the lighter Mg isotopes and available state-of-the-art theoretical model predictions. We will discuss a possible explanation for the observed structure in terms of weak-binding effects.

In 1956 Kerman published a seminal paper on rotational perturbations in nuclei [3]. In the second part of the talk, we consider Kerman’s problem when one of the single-particle levels involved is a resonant state. We will present some preliminary results showing the behavior of the moment of inertia and the decoupling parameter as a function of the state width.

 

[1] J. Dobaczewski, et al. Prog. Part. Nucl. Phys. 59, 432 (2007).
[2] H. L. Crawford, et al. Phys. Rev. Lett. 122, 052501 (2019).
[3] A. K. Kerman, Mat. Fys. Medd. Dan. Vid. Selsk. 30, no. 15 (1956).

N.B. The seminar material is based upon work supported by the U.S. DOE, Office of Science, Office of Nuclear Physics, under Contract No. DEAC0205CH11231.

This seminar will be organized in the framework of the ESNT workshop on proton-neutron pairing, held at Orme, between September 2nd till 6th. See the web page for updated information.


http://esnt.cea.fr/Phocea/Page/index.php?id=84
Contact : Valerie LAPOUX

 

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