Ruslan Magaña Vsevolodovna

INFN - Istituto Nazionale di Fisica Nucleare, Genova, Italy · Physics

We present a new application of the Interacting Boson Model (IBM) and its extensions for describing double charge exchange reactions. The study of double charge exchange reactions induced by heavy ions involving candidate nuclei for neutrinoless double beta decay is a complex task carried out by the NUMEN collaboration. This investigation faces the...

Background: A systematic exploration of one-nucleon transfer reactions induced by the (O18,F19) and (O18,O17) reactions on different targets (C12, O16, Al27, Ca40, Ti48, Se76, Sn116) is being performed at the Istituto Nazionale di Fisica Nucleare–Laboratori Nazionali del Sud (INFN-LNS) at beam energies higher than Coulomb barrier. A featured aspect...

Here, we study the neutrinoless double-$\beta$ ($0\nu\beta\beta$) decay between the ground state and the first $2^+$ state of $^{76}\mbox{Ge} \rightarrow {}^{76}\mbox{Se}$, $^{82}\mbox{Se} \rightarrow{}^{82}\mbox{Kr}$, $^{130}\mbox{Te} \rightarrow {}^{130}\mbox{Xe}$ and $^{136}\mbox{Xe} \rightarrow {}^{136}\mbox{Ba}$ systems. The relevant nuclear m...

Spectroscopic Amplitudes (SA) in the Interacting Boson Fermion Fermion Model (IBFFM) are necessary for the computation of $0\nu\beta\beta$ decays but also for cross sections of heavy-ion reactions, in particular, Double Charge Exchange reactions for the NUMEN collaboration, if one does not want to use the closure limit. We present for the first tim...

The structure of odd-A Rh115,117 and Pd115,117 isotopes is studied by means of the neutron-proton interacting boson-fermion model (IBFM-2). JP=12+ quantum number assignment for the Pd115,117 ground states is critically discussed and the predicted energy levels are compared to the existing experimental data. The resulting nuclear wave functions are...

The structure of odd-$A$ $^{(115,117)}$Rh and $^{(115,117)}$Pd isotopes is studied by means of the neutron-proton Interacting Boson-Fermion Model (IBFM-2). $J^P = \frac{1}{2}^+$ quantum number assignment for the $^{(115,117)}$Pd ground-states is critically discussed and the predicted energy levels are compared to the existing experimental data. The...

Background: Heavy-ion induced two-nucleon transfer reactions are powerful tools to reveal peculiar aspects of the atomic nucleus, such as pairing correlations, single-particle and collective degrees of freedom, and more. Also, these processes are in competition with the direct meson exchange in the double charge exchange reactions, which have recen...

The formalism to describe heavy-ion double charge exchange (DCE) processes in the eikonal and small-momentum transfer approximations introduced in Phys. Rev. C 98 , 061601(R) (2018) is briefly discussed. It is also shown that, under the previous approximations, the heavy-ion DCE cross-section can be factorized in terms of a reaction and a nuclear p...

Neutrinoless double beta decay (0v\b{eta}\b{eta}) is considered the best potential resource to access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are their own anti-particles (Majorana particles). Presently, this physics case is one of the most important research "beyond Standard Model" and might guide the...

The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of Heavy Ion (HI) induced Double Charge Exchange (DCE) reaction cross sections. In particular, the (¹⁸O,¹⁸Ne) and (²⁰Ne,²⁰O) reactions are used a...

Using the eikonal approximation and small momentum transfer approximation a simple model for differential cross section for double charge exchange has been derived and under those hypothesis a factorization of the reaction part and the nuclear part holds. Moreover, the explicit form for a double charge exchange effective potential has been derived...

The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0υββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. Particular interest is given to the (¹⁸O,¹⁸Ne) and (²⁰Ne,...

The NUMEN main goal is the extraction from measured cross-sections of “data-driven” information on Nuclear Matrix Elements for all the systems candidate for 0νββ. The idea is to use as experimental tool Heavy Ions –Double Charge Exchange (HI-DCE) reactions. Crucial for the experimental challanges is the INFN Laboratori Nazionali del Sud (LNS) facil...

An updated overview of recent results on Heavy-Ion induced reactions of interest for neutrinoless double beta decay is reported in the framework of the NUMEN project. The NUMEN idea is to study heavy-ion induced Double Charge Exchange (DCE) reactions with the aim to get information on the nuclear matrix elements for neutrinoless double beta (0νββ)...

The possibility to use a special class of heavy-ion induced direct reactions, such as double charge exchange reactions, is discussed in view of their application to extract information that may be helpful to determinate the nuclear matrix elements entering in the expression of neutrinoless double beta decay half-life. The methodology of the experim...

We introduce the formalism to describe heavy-ion double-charge-exchange (DCE) processes in the eikonal approximation. We focus on the low-momentum-transfer limit, corresponding to the differential cross section at θ=0∘, and for the first time, we show that it is possible to factorize the DCE cross section in terms of reaction and nuclear parts. Whe...

The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of hea...

In this contribution we present a study of a direct and sequential two-nucleon transfer within the microscopic Interacting Boson Model (IBM-2) and Interacting Boson- Fermion Model (IBFM), respectively. We present our preliminary results for heavy-ion double-charge-exchange⁴⁰Ca(¹⁸O,¹⁸Ne)⁴⁰ArG.S. differential cross section too.

We introduce the formalism to describe heavy-ion Double-Charge-Exchange (DCE) processes in the eikonal approximation. We focus on the low-momentum-transfer limit -- corresponding to the differential cross section at $\theta=0^\circ$ -- and, for the first time, we show that it is possible to factorize the DCE cross-section in terms of reaction and n...

The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of hea...

Theoretical studies of two nucleon transfer reactions, double charge exchange and single charge exchange reactions and nuclear matrix elements involved in neutrinoless double beta processes have been developed in this thesis.

A study of the two-neutron transfer reaction of the ¹⁸O + ⁶⁴Ni system at 84 MeV incident energy to the ground and first 2+ excited state of the residual ⁶⁶Ni nucleus is presented. The experiment was performed at the INFN-LNS (Italy) by using the large acceptance MAGNEX spectrometer. Theoretical models are used in order to disentangle the competitio...

Neutrinoless double beta decay (0vββ) is considered the best potential resource to access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are their own anti-particles (Majorana particles). Presently, this physics case is one of the most important research "beyond Standard Model" and might guide the way towards...

Neutrinoless double beta decay (0νββ) is considered the best potential resource to determine the absolute neutrino mass scale. Moreover, if observed, it will signal that the total lepton number is not conserved and neutrinos are their own anti-particles. Presently, this physics case is one of the most important research “beyond Standard Model” and...

Recently, various two-neutron transfer studies using the (O18,O16) reaction were performed with a large success. This was achieved because of a combined use of the microscopic quantum description of the reaction mechanism and of the nuclear structure. In the present work we use this methodology to study the two-neutron transfer reaction of the O18+...

The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. Particular attention is given to the (¹⁸O,¹⁸Ne) and (²⁰Ne...

We describe the relativistic interacting quark–diquark model formalism and its application to the calculation of strange and nonstrange baryon spectra. The results are compared to the existing experimental data. We also discuss the application of the model to the calculation of other baryon observables, like baryon magnetic moments, open-flavor str...

An innovative technique to access the nuclear matrix elements entering the expression of the life time of the double beta decay by relevant cross section measurements of double charge exchange reactions is proposed. A key aspect of the project is the use of the MAGNEX large acceptance magnetic spectrometer, for the detection of the ejectiles, and o...

We aim to determine the intensities for the two-nucleon transfer reaction from $^{194}$Pt to $^{196}$Au. We will consider the formalism of nuclear supersymmetry for the Pt-Au region with the symmetry $U_\nu(6/12)\otimes U_\pi(6/4)$. The two nucleon transfer matrix elements are calculated via two one nucleon transfer reactions. One-nucleon transfe...

Se presenta una aproximacion algebraica para determinar el espectro electronico de moleculas diatomicas usando simetrıas dinamicas del algebra U(4) y U(8). Las simetrıas dinamicas rompen la degeneracion de los niveles energeticos pero no cambian las funciones de onda. Se introduce el concepto de Supersimetrıa Molecular donde un Hamiltoniano que per...

The Hamiltonian for an atom of N electrons is built, different approaches are presented to solve it. Variational Hartree-Fock is introduced and explained in detail applied to the Helium atom. El Hamiltoniano para un a ́tomo de N electrones es construido, se presentan difer- entes enfoques para resolverlos. Se introduce el m ́etodo variacional de H...

In nuclear supersymmetry the spectroscopic properties of even-even, odd-even and oddodd nuclei are strongly related to one another. It is shown that these correlations can be derived in terms of SU(3) isoscalar factors by employing the concept of generalized F-spin. As an application we discuss the correlations between one-proton and one-neutron tr...

The basic fundamentals of nuclear physics applied to nuclei with high collective degree are studied. Nuclear transfer reactions in the context of Nuclear Supersymmetry and extensions are presented. The concepts of collective interactions based on groups of symmetries are developed in according to the Theory of Interacting Bosons Model IBM. It was r...

We study the equation of state (EOS) of nuclear matter as function of density. We expand the energy per particle (E/A) of symmetric infinite nuclear matter in powers of the density to take into account 2,3,. . .,N-body forces. New EOS are proposed by fitting ground state properties of nuclear matter (binding energy, compressibility and pressure) an...

The nuclei belonging to a supersymmetric quartet are described by a single Hamiltonian, and hence the wave functions, transition and transfer rates are strongly correlated. The correlations between different transfer reactions can be derived in an elegant and explicit way by a generalization of the concept of F-spin. Group theoretically, the genera...