Study of single-nucleon transfer reactions in the 18O+48Ti collision at 275 MeV

The study of single-nucleon transfer reactions for the 18O+48Ti system was pursued at the energy of 275 MeV as part of a more systematic study which is undertaken within the NUMEN and NURE experimental campaigns. The aim is to measure the complete set of available reaction network which are characterized by the same initial and final-state wavefunctions as the more suppressed double charge exchange reactions. Understanding the degree of competition between successive nucleon transfer and double charge exchange reactions is crucial for the description of the meson-exchange mechanism. In this respect, angular distribution measurements for one- and twonucleon transfer reactions for the 18O+48Ti system were carried out at theMAGNEX facility of INFN-LNS in Catania. An overview of the data analysis for the 48Ti(18O,19F)47Sc and 48Ti(18O,17O)49Ti reactions will be presented

Experimental challenges for the measurement of the116Cd(20Ne,20O)116Sn double charge exchange reaction at 15 AMeV

The knowledge of the nuclear matrix elements (NME) entering in the expression of the half-life of the neutrinoless double beta decay is fundamental for neutrino physics . Information on the nuclear matrix elements can be obtained by measuring the absolute cross section of double charge exchange nuclear reactions. The two processes present some similarities, the initial and final-state wave functions are the same and the transition operators are similar. The experimental measurements of double charge exchange reactions induced by heavy ions present a number of challenging aspects, since such reactions are characterized by very low cross sections. Such difficulties are discussed for the measurement of the 116Cd(20Ne,20O)116Sn reaction at 15 AMeV

A multi–channel study of the 20^{20}Ne + 130^{130}Te system within the NUMEN project

International audienceThe NUMEN project aims to measure specific reaction cross sections to provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double beta decay (0νββ). In particular, it was proposed to use heavy – ion induced double charge exchange reactions as tools towards the determination of information on the nuclear matrix elements of 0νββ, strongly motivated by a number of similarities between the two processes. To this extent, the $^{20}$Ne + $^{130}$Te system was experimentally investigated in a multi-channel approach by measuring the complete net of reactions channels, namely double charge exchange, single charge exchange, elastic and inelastic scattering, one – and two – nucleon transfer reactions, characterized by the same initial projectile and target nuclei. The goal of the study is to fully characterize the properties of the nuclear wavefunctions entering in the 0νββ decay nuclear matrix elements. The experimental setup, the data reduction and some of the obtained results for the $^{20}$Ne + $^{130}$Te system will be presented and discussed

One-neutron transfer reaction in the <math><mrow><mmultiscripts><mi mathvariant="normal">O</mi><mprescripts/><none/><mn>18</mn></mmultiscripts><mo>+</mo><mmultiscripts><mi>Ti</mi><mprescripts/><none/><mn>48</mn></mmultiscripts></mrow></math> collision at 275 MeV

International audienceThe present article reports new data on the Ti48(O18,O17)Ti49 reaction at 275 MeV incident energy as part of the systematic research pursued within the NUMEN (NUclear Matrix Elements for Neutrinoless double β decay) project. Supplementary measurements of the same reaction on O16 and Al27 targets were also performed in order to estimate the background arising from the use of a composite target (TiO2+Al27). These data were analyzed under the same theoretical framework as those obtained with the titanium target in order to reinforce the conclusions of our analysis. Differential cross-section angular distribution measurements for the O8+17 ejectiles were performed in a wide angular range by using the MAGNEX large acceptance magnetic spectrometer. The experimental results were analyzed within the distorted-wave and coupled-channels Born approximation frameworks. The optical potentials at the entrance and exit channels were calculated in a double folding approach adopting the São Paulo potential, and the spectroscopic amplitudes for the projectile and target overlaps were obtained from large-scale shell model calculations. The differential cross sections are well described by the theoretical calculations, where a weak coupling to collective excitations of projectile and target is inferred. The sensitivity of transfer cross sections on different model spaces adopted in nuclear structure calculations is also discussed

Study of single-nucleon transfer reactions in the ¹⁸O+⁴⁸Ti collision at 275 MeV

International audienceThe study of single-nucleon transfer reactions for the 18O+48Ti system was pursued at the energy of 275 MeV as part of a more systematic study which is undertaken within the NUMEN and NURE experimental campaigns. The aim is to measure the complete set of available reaction network which are characterized by the same initial and final-state wavefunctions as the more suppressed double charge exchange reactions. Understanding the degree of competition between successive nucleon transfer and double charge exchange reactions is crucial for the description of the meson-exchange mechanism. In this respect, angular distribution measurements for one- and twonucleon transfer reactions for the 18O+48Ti system were carried out at theMAGNEX facility of INFN-LNS in Catania. An overview of the data analysis for the 48Ti(18O,19F)47Sc and 48Ti(18O,17O)49Ti reactions will be presented.</jats:p

<math><mmultiscripts><mi mathvariant="normal">O</mi><mprescripts/><none/><mn>18</mn></mmultiscripts><mo> </mo><mo>+</mo><mo> </mo><mmultiscripts><mi mathvariant="normal">Ti</mi><mprescripts/><none/><mn>48</mn></mmultiscripts></math> elastic and inelastic scattering at 275 MeV

International audienceBackground: In recent years, the NUMEN project has highlighted that the systematic study of double charge exchange (DCE) nuclear reactions could provide precious information on the nuclear matrix elements of neutrinoless double β decay. To achieve this goal, a multichannel approach was adopted, where a plethora of different reaction channels is measured under the same experimental conditions and analyzed in a coherent framework. In this context, the initial (ISI) and final (FSI) state interactions are fundamental building blocks to investigate all the relevant direct nuclear reactions. To date, such building blocks are not sufficiently established for many of the projectile-target pairs of interest for NUMEN experiments. This is also the case of the O18+Ti48 system, which is relevant for the double β decay of the Ca48 nucleus into the Ti48 one.Purpose: This work aims at deducing the ISI to be used in the multichannel study of the O18+Ti48 collision at 275 MeV incident energy. To this purpose, the optical potential and the strength of the couplings between elastic and inelastic scattering channels are determined and characterized by comparison with new experimental data.Methods: Cross section angular distributions were measured for the elastic and low-lying inelastic scattering channels in a wide range of momentum transfer. Experimental data were compared to theoretical calculations performed in optical model (OM), distorted-wave Born approximation (DWBA), coupled channels (CC), and coupled channels equivalent polarization potential (CCEP) approaches. For all of them, the São Paulo double-folding potential was adopted as the optical potential. The comparison between the predictions of the OM/DWBA and CC frameworks allowed to evaluate the strength of the couplings to the inelastic channels which were explicitly taken into account. Within the CC formalism, different coupling schemes were compared to assess the contributions of the states included in the model space. A further test of our approach was carried out by analyzing the experimental data of the same system at 54 MeV incident energy.Results: The achieved energy resolution allowed to resolve the elastic scattering and the excitation of the 21+ state of the Ti48 nucleus. A broad structure, associated to the superposition of the inelastic transitions to the 21+ state of O18 and to three excited states of Ti48, was also observed. The OM and DWBA calculations are not able to reproduce the experimental elastic and inelastic angular distributions in the explored range of momentum transfer. A significant improvement in the description of the data is found by using the CC approach. In particular, when the 21+ and 31− collective states of projectile and target and their simultaneous excitations are included in the coupling scheme, a satisfactory agreement is achieved. The CCEP predictions describe reasonably well the elastic scattering data.Conclusions: Channel coupling effects have to be taken into account for a good description of the elastic and inelastic experimental angular distributions in the measured range of momentum transfer. The inclusion of such couplings in the ISI is envisaged for the analysis of all the direct nuclear reactions induced by the O18+Ti48 collision in this incident energy region

Post-stripper study for the (20Ne,20^{20}Ne, ^{20}O) double charge exchange reaction at zero degrees with the MAGNEX spectrometer

International audienceA study of different post-stripper materials for the (20Ne, 20O) double charge exchange and (20Ne, 20F) single charge exchange reactions at zero degrees using the MAGNEX spectrometer at 22 and 15 AMeV is presented. All these experiments belongs to the experimental campaign planned in the NUMEN project (NUclear Matrix Elements for Neutrinoless double beta decay)

One-proton transfer reaction for the 18O+48Ti^{18}\mathrm{O}+^{48}\mathrm{Ti} system at 275 MeV

International audienceSingle-nucleon transfer reactions are processes that selectively probe single-particle components of the populated many-body nuclear states. In this context, recent efforts have been made to build a unified description of the rich nuclear spectroscopy accessible in heavy-ion collisions. An example of this multichannel approach is the study of the competition between successive nucleon transfer and charge exchange reactions, the latter being of particular interest in the context of single and double beta decay studies. To this extent, the one-proton pickup reaction Ti48(O18,F19)Sc47 at 275 MeV was measured for the first time, under the NUMEN experimental campaign. Differential cross-section angular distribution measurements for the F19 ejectiles were performed at INFN-LNS in Catania by using the MAGNEX large acceptance magnetic spectrometer. The data were analyzed within the distorted-wave and coupled-channels Born approximation frameworks. The initial and final-state interactions were described adopting the São Paulo potential, whereas the spectroscopic amplitudes for the projectile and target overlaps were derived from shell-model calculations. The theoretical cross sections are found to be in very good agreement with the experimental data, suggesting the validity of the optical potentials and the shell-model description of the involved nuclear states within the adopted model space

Recent results on the analysis of the 48^{48}Ti(18^{18}O, 20^{20}Ne)46^{46}Ca reaction at 275 MeV

International audienceThe $^{18}$O+$^{48}$Ti reaction was studied at the energy of 275 MeV for the first time under the NUMEN and NURE experimental campaigns with the aim of investigating the complete reaction network potentially involved in the $^{48}$Ti→$^{48}$Ca double charge exchange transition. Understanding the degree of competition between successive nucleon transfer and double charge exchange reactions is crucial for the description of the meson exchange mechanism. Into this context, angular distribution measurements for one- and two-nucleon transfer reactions for the system $^{18}$O+$^{48}$Ti were performed at the MAGNEX facility of INFN-LNS in Catania. An overview of the status of the analysis for the two-proton transfer reaction will be given