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We approach the calculation of the nuclear matrix element of the neutrinoless double-β decay process, considering the light-neutrino-exchange channel, by way of the realistic shell-model. In particular the focus of our work is spotted on the role of the short-range correlations, which should be taken into account because of the short-range repulsion of the realistic potentials. Our shell-model wave functions are calculated using an effective Hamiltonian derived from the high-precision CD-Bonn nucleon-nucleon potential, the latter renormalized by way of the so-called Vlow-k approach. The renormalization procedure decouples the repulsive high-momentum component of the potential from the low-momentum ones by the introduction of a cutoff Λ, and is employed to renormalize consistently the two-body neutrino potentials to calculate the nuclear matrix elements of candidates to this decay process in mass interval ranging from A = 76 up to A = 136. We study the dependence of the decay operator on the choice of the cutoff, and compare our results with other approaches that can be found in present literature.

•Toxicological data on seized material in the Naples area in 2013–2018 are presented.•Unlike European trends there is a prevalence of herbal on resin derivatives.•Deferred people were male, 30–40 yr, or younger for cannabis.•Areas with higher amounts of seizures are at the higher risks of mafia homicides.•Mafia proceeds from classical drugs may account for the absence of NPS. The study presents results of toxicological analysis performed on seized material in Neapolitan area in the period from 2013 to 2018. A constancy in THC and heroin percentages is evidenced (%THC ~10% and ~11.5% for marijuana and hashish; heroine: 20–24%), with mean values exceeding the European data. Data on cocaine revealed a constant increment of active principle percentage over the studied period (from 40% in 2013 to ~65% in 2018), with peak of 70% in 2017; also, number of samples exceeding the mean value increased over years. Active principles contents resulted higher than the ones reported in other Italian area ever the same period; marijuana was prevalent on hashish, confirming an Italian trend different from other European countries. A map of the Campania region evidenced two main “storage” districts, one corresponding to the city center and the second located in the northern part. If compared with literature data on the presence of local mafia, these areas are perfectly superimposable to those with the highest risk of homicides, thus confirming the degree of radicalization of local organizations and the relative weight of proceeds from drugs sale. Moreover, such radicalization within the territory seems to be the main reason of the absence of new psychoactive substances among the seized material.

Electron-capture reaction rates on medium-heavy nuclei are a key ingredient to describe the evolution of core-collapse and thermonuclear supernovae. To estimate these rates it is necessary to know the Gamow-Teller strength distributions involved. In this paper we report some preliminary results of the calculations of Gamow-Teller strength distributions for pf-shell nuclei performed in the framework of the realistic shell model.

The need of a reliable calculation of the nuclear matrix elements for the 0 νββ decay has ignited a new interest about the quenching of the axial coupling constant g A , a procedure introduced to reproduce experimental results connected with GT decays. The goal of this work is to present a preliminary study to tackle this problem within the framework of the realistic shell model.

We report on the calculation of double-β decay properties of 130Te and 136Xe within the framework of the realistic shell model. The effective shell-model Hamiltonian and Gamow-Teller transition operator are derived by way of many-body perturbation theory, in order to not to resort to an empirical quenching of the axial coupling constant gA. The results compare well with experimental data, paving the way to the calculation of the neutrinoless double-β decay nuclear matrix element for the nuclei that are currently the experimental target for the detection of this process. In this work we investigate about the perturbative properties of our approach, and the theoretical reliability of the realistic shell model.

We report on a shell-model study of Sn isotopes beyond N 82 employing a realistic effective interaction derived from the CD-Bonn nucleon-nucleon potential renormalized through use of the Vlow-k approach. At present, the most exotic Sn isotope for which some experimental information exists is 134Sn with an N/Z ratio of 1.68. It is the aim of our study to compare the results of our calculations with the available experimental data and to make predictions for the neighboring heavier isotopes which may be within reach of the next generation of radioactive ion beam facilities. The very good agreement between theory and experiment obtained for 134Sn gives confidence in the predictive power of our realistic shell-model calculations.

This paper presents a short overview of the shell-model approach with realistic effective interactions to the study of exotic nuclei. We first give a sketch of the current state of the art of the theoretical framework of this approach, focusing on the main ingredients and most relevant recent advances. Then, we present some selected results for neutron-rich nuclei in various mass regions, namely oxygen isotopes, N 40 isotones, and nuclei around 132Sn, to show the merit as well as the limits of these calculations.

A major requirement for a nuclear model is, not only to reproduce and describe accurately the available experimental data, but also to provide reliable predictions for physical quantities not yet measured. Over the past two decades, we have performed various realistic shell-model calculations for nuclei in different mass regions, which have all yielded results in good agreement with the available experimental data. In this paper we present some selected results illustrating their predictive power.

We investigate the pairing properties of an effective shell-model interaction defined within a model space outside 132Sn and derived by means of perturbation theory from the CD-Bonn free nucleon-nucleon potential. It turns out that the neutron pairing component of the effective interaction is significantly weaker than the proton one, which accounts for the large pairing gap difference observed in the two-valence identical particle nuclei 134Sn and 134Te. The role of the contribution arising from one particle-one hole excitations in determining the pairing force is discussed and its microscopic structure is also analyzed in terms of the multipole decomposition.

Lifetimes of the 21+ states in 44Ti, 48,50Cr, and 52Fe were determined with high accuracy exploiting the recoil distance Doppler-shift method. The reduced E2 transition strengths of 44Ti and 52 Fe differ considerably from previously known values. A systematic increase in collectivity is found for the N = Z nuclei compared to neighboring isotopes. The B(E2) values along the Ti, Cr, and Fe isotopic chains are compared to shell-model calculations employing established interactions for the 0f 1p shell, as well as a novel effective shell-model Hamiltonian starting from a realistic nucleon-nucleon potential. The theoretical approaches underestimate the B(E2) values for the lower-mass Ti isotopes. Strong indication is found for particle-hole cross-shell configurations, recently corroborated by similar results for the neighboring isotone 42 Ca. A detailed manuscript has meanwhile been published in Physics Letters B [1].