Departamento de Física
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/785
Navegar
5 resultados
Resultados da Pesquisa
- Multichannel experimental and theoretical approach to the C 12 (O 18, F 18) B 12 single-charge-exchange reaction at 275 MeV: Initial-state interaction and single-particle properties of nuclear wave functions(2023) SPATAFORA, A.; CARBONE, D.; CAPPUZZELLO, F.; CAVALLARO, M.; ACOSTA, L.; AGODI, C.; AMADOR-VALENZUELA, P; BORELLO-LEWIN, T.; BRISCHETTO, G. A.; CALABRESE, S.; CALVO, D.; CAPIROSSI, V.; CHAVEZ LOMELI, E. R.; CIRALDO, I.; DE GREGORIO, G.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FOTI, A.; GARGANO, A.; HACISALIHOGLU, A.; IAZZI, F.; LA FAUCI, L.; LINARES, R.; LUBIAN, J.; MEDINA, N.; MORALLES, M.; OLIVEIRA, J. R. B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RUSSO, G.; SGOUROS, O.; Marcilei Aparecida Guazzelli; SOLAKCI, S. O.; SOUKERAS, V.; SOULIOTIS, G.; TORRESI, D.; TUDISCO, S.; YILDIRIM, A.; ZAGATTO, V. A. B.© 2023 American Physical Society. Background: Single-charge-exchange reactions are appropriate tools to study the nuclear response to one-particle/one-hole isospin probes, gaining additional interest from the connection to beta decay. This analogy has been recently extended to second order, connecting double-charge-exchange reactions and double beta decays. Nowadays, the availability of powerful experimental setups and advanced nuclear theories and models allows one to access precious information on key nuclear structure aspects embedded in the widely sought neutrinoless double beta decay. Purpose: We intend to bring to light the main nuclear structure and reaction features involved in the O18+C12 collision at 275 MeV incident energy. In this paper, the main focus is on the role of the initial- and final-state interactions in the overall reaction dynamics and on the single-particle nuclear structure properties accessed via the study of single-nucleon transfer reactions. Forthcoming articles will be devoted to go into the details of the response to one- and two-particle/hole isospin probes. Methods: Cross-section energy spectra and angular distributions were measured in a unique experimental setup for the C12(O18,O18)C12 elastic and inelastic scattering, the C12(O18,O17)C13 one-neutron stripping, the C12(O18,F19)B11 one-proton pickup, and the C12(O18,F18)B12 single-charge-exchange nuclear reactions. A unique comprehensive and coherent theoretical calculation, able to describe the whole network of direct reactions using state-of-the-art nuclear structure and reaction theories, was performed, and it is presented for the first time in this article. This holistic approach, applied both to the experimental and theoretical analysis, is the main feature and worth of the work here presented. Results: The energy and angular resolutions achieved in each reaction channel allowed us to isolate specific transitions and to map the diffraction patterns in the angular distributions. The cross-section calculations describe well the experimental data, both in terms of the absolute values and diffraction patterns. Although the distorted wave Born approximation (DWBA) calculations prove to be accurate in describing all the studied channels, better results are achieved when the couplings to inelastic transitions in both the incoming and outgoing partitions are introduced, as done in the coupled channels Born approximation (CCBA) calculations. Otherwise, no real improvement is found when the coupling effects among different partitions are explicitly taken into account in the coupled reaction channels (CRC) calculations. Conclusions: The multichannel approach proposed in this paper is a promising method for accurate investigations of direct reactions originating in heavy-ion collisions. This is quite appealing for the precise spectroscopy of heavy nuclei proposed in many areas of nuclear physics. An example is the NUMEN project with its challenging commitment to provide valuable information on neutrinoless double beta decay nuclear matrix elements from single- and double-charge-exchange cross-section measurements.
- Analysis of the one-neutron transfer reaction in O 18 + Se 76 collisions at 275 MeV(2022) CIRALDO I.; CAPPUZZELLO, F.; CAVALLARO, M.; CARBONE, D.; BURRELLO, S.; SPATAFORA, A.; GARGANO, A.; DE GREGORIO, G.; VSEVOLODOVNA, R. I. M.; ACOSTA, L.; AGODI, C.; AMADOR-VALENZUELA, P.; BORELLO-LEWIN, T.; BRISCHETTO, G. A.; CALABRESE, S.; CALVO D.; CAPOROSSI, V.; LOMELI, E. R. C.; COLONNA, M.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FOTI, A.; HACISALIHOGLU, A.; IAZZI, F.; LA FAUCI, L.; LINARES, R.; MEDINA, N. H.; MORALES, M.; OLIVEIRA, J. R. B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RUSSO, G.; SANTOPINTO. E.; SGOUROS, O.; Marcilei Aparecida Guazzelli; SOLAKCI, S. O.; SOUKERAS, V.; SOULIOTIS, G.; TORRES, D.; TUDISCO, S.; YILDIRIM, A.; ZAGATTO, V. A. B.© 2022 American Physical Society.Background: Heavy-ion one-nucleon transfer reactions are promising tools to investigate single-particle configurations in nuclear states with and without the excitation of the core degrees of freedom. A careful determination of the spectroscopic amplitudes of these configurations is essential for the accurate study of other direct reactions as well as β decays. In nucleon transfer reactions core excitations, for both target and projectile systems, are best approached via coupled-channels reaction schemes. Despite being notoriously demanding in terms of computing resources, coupled-channels analyses are progressively becoming more affordable even within model spaces large enough for tackling medium mass nuclei. In this context, the Se76(O18,O17)Se77 reaction, here under study, gives a quantitative access to the relevant single-particle orbitals and core polarization configurations built on Se76. This is particularly relevant, since it provides data-driven information to constrain nuclear structure models for Se76, which is the daughter nucleus in the Ge76 ββ decay. This reaction is one of the systems studied in the frame of the Nuclear Matrix Elements for Neutrinoless double beta decay project. Purpose: We want to analyze transitions to low-lying excited states of the residual and ejectile nuclei in the Se76(O18,O17)Se77 one-neutron stripping reaction at 275-MeV incident energy and determine the role of single-particle and core excitation in the description of the measured cross sections. In addition, we explore the sensitivity of the calculated cross section to different nuclear structure models. Methods: The excitation energy spectrum and the differential cross-section angular distributions are measured using the MAGNEX large acceptance magnetic spectrometer for the detection of the ejectiles and the missing mass technique for the reconstruction of the reaction kinematics. The data are compared with calculations based on distorted-wave Born approximation, coupled-channels Born approximation, and coupled reaction channels adopting spectroscopic amplitudes for the projectile and target overlaps derived by large-scale shell-model calculations and interacting boson-fermion model. Results: Peaks in the energy spectra corresponding to groups of unresolved transitions to Se77 and O17 are identified. The experimental cross sections are extracted and compared to theoretical calculations. A remarkable agreement is found, without using any scaling factors, demonstrating that the adopted models for nuclear structure and reaction take into account the relevant aspects of the studied processes. The main transitions which contribute to the cross section of each peak are identified. Conclusions: The coupling with the inelastic channels feeding states in entrance and exit partitions is important in the one-neutron transfer reaction and should be accounted for in future analyses of other direct reactions such as single and double charge exchange processes involving Se76 isotope. The description of Se77 indicates the need of a large model space, in the view of an accurate description of the low-lying states, a feature that should be likely accounted even for ββ-decay studies of Ge76.
- O 18 + Se 76 elastic and inelastic scattering at 275 MeV(2021) LA FAUCI, L.; SPATAFORA, A.; CAPPUZZELLO, F.; AGODI, C.; CARBONE, D.; CAVALLARO, M.; LUBIAN, J.; ACOSTA, L.; AMADOR-VALENZUELA, P.; BORELLO-LEWIN, T.; BRISCHETTO, G. A.; CALABRESE, S.; CALVO, D.; CAPIROSSI, V.; CHAVEZ LOMELI, E. R.; CIRALDO, I.; CUTULI, M.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; SISICHELLA, M.; FOTI, A.; Marcilei Aparecida Guazzelli; HACISALIHOGLU, A.; IAZZI, F.; LINARES, R.; MA, J.; MEDINA, N. H.; MORALLES, M.; OLIVEIRA, J. R. B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RIES, P. C.; RUSSO, G.; SGOUROS, O.; SOLAKCI, S. O.; SOUHERA, V.; SOULIOTIS, G.; TORRESI, D.; TUDISCO, S.; WANG. J.; YANG. Y.; YILDIRIN, A.; ZAGATTO, V. A. B.© 2021 American Physical Society.Background: An accurate description of the initial and final state interactions in the O18+Se76 collision is demanded by the NUMEN project. The study of single and double charge exchange nuclear reactions is the main purpose for NUMEN, since these can be used as tools to provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double-β decay. To date, the details of the optical potentials and nuclear response to isospin operators for many of the projectile-target systems proposed for the NUMEN double charge exchange studies are poorly known. The O18+Se76 case, here under study, is particularly relevant due to its connection with the Ge76 neutrinoless double-β decay.Purpose: In this work the authors want to characterize the initial-state interaction for the O18+Se76 reactions at 275 MeV incident energy determining the optical potential and evaluating the effect of couplings with the inelastic scattering on the elastic channel.Methods: The angular distributions of differential cross section were measured in the angular region between 4° and 22° in the center-of-mass reference frame. The cross sections were compared with theoretical calculations, that adopt different optical potentials. Coupling effects on the elastic channel were determined into the coupled channels formalism.Results: The excitation energy spectrum of the colliding nuclei and the cross section angular distributions were measured with satisfactory energy resolution. The elastic scattering cross section is not well reproduced in the full angular range explored when the optical model approach is adopted. A good agreement is found using coupled channel calculations. The initial state interaction for the O18+Se76 nuclear reactions at 275 MeV is determined.Conclusions: Coupled channels effects are crucial to obtain a good description of the measured elastic and inelastic channels cross sections, even at large transferred momenta where the optical model approach fails in reproducing the experimental data. The role of channel coupling could be relevant also in the analysis of other open reaction channels in the same collision and should be accounted for in double charge exchange analyses as well.
- O 18 -induced single-nucleon transfer reactions on Ca 40 at 15.3A MeV within a multichannel analysis(2021) CALABRESE, S.; CAVALLARO, M.; CARBONE, D.; CAPPUZZELLO, F.; AGODI, C.; BURRELLO, S.; DE GREGORIO, S.; FERREIRA, J. L.; GARGANO, A.; SGOUROS, O.; ACOSTA, L.; AMADOR-VALENZUELA, P.; BELLONE, J. I.; BORELLO-LEWIN, T.; BRISCHETTO, G. A.; CALVO, D.; CAPIROSSI, V.; CHACEZ LOMELI, E. R.; CIRALDO, I.; COLONNA, M.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FOTI, A.; Marcilei Aparecida Guazzelli; HACISALIHOGLU, A.; IAZZI, F.; LA FAUCI, L.; LAY, J. A.; LINARES, R.; LUBIAN, J.; MEDINA, N. H.; MORALLES, M.; OLIVEIRA, J. R. B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RUSSO, G.; SOLAKCI, S. O.; SOUKERAS, V.; SOULIOTIS, G.; SPATAFORA, A.; TORRRESI, D.; TUDISCO, S.; YILDIRI, A.; ZAGATTO, V. A. B.© 2021 American Physical Society. Background: Nucleon transfer reactions are selective tools for nuclear physics investigations. The theoretical and computational limits affecting in the past their data analysis could be nowadays surmounted thanks to the advent of methods with refined approximations and constraints, even when heavy-ion collisions are considered. Purpose: Modern microscopic calculations of heavy-ion-induced transfer reactions combined with precise experimental data offer the chance for accurately testing different reaction models as well as the nuclear structure description of the involved nuclear states. Method: Single proton and neutron transfer reactions were measured with the MAGNEX magnetic spectrometer for the O18+Ca40 system at 15.3A MeV. Excitation energy spectra and angular differential cross section distributions were extracted. The experimental results are compared with theoretical calculations performed in distorted wave and coupled channel Born approximation. The use of a coupled channel equivalent polarization potential to effectively describe the coupling effects affecting the initial state interaction is also considered. Spectroscopic amplitudes derived from a large-scale shell model with appropriate interactions adapted for the involved nuclei are employed. Results: Our theoretical calculations are in good agreement with experimental data, without the need for any scaling factor, validating the adopted reaction and nuclear structure parameters. Moreover, under the present experimental conditions, a weak dependence of the obtained results on the choice of the reaction models was observed. Conclusions: The good agreement between experimental and theoretical results validates the reliability of the parameter sets entering the calculations. They are extracted from or tested in complementary analyses of other reaction channels under the same experimental conditions. Such a multichannel approach represents the best option to pursue a solid, comprehensive, and model-independent description of the single-nucleon transfer reactions. The successful description of the present one-nucleon transfer data is also propaedeutic to the accurate assessment, under the same theoretical description, of higher-order transfer processes, like the sequential nucleon transfer mechanisms which are in competition with the direct charge exchange reactions.
- One-proton transfer reaction for the O 18 + Ti 48 system at 275 MeV(2021-09-05) SGOUROS, O.; CAVALLARO, M.; CAPPUZZELLO, F.; CARBONE, D.; AGODI, C.; GARGANO, A.; DE GREGORIO, G.; ALTANA, C.; BRISCHETTO, G. A.; BURRELLO, S.; CALABRESE, S.; CALVO, D.; CAPIROSSI, V.; CHAVEZ LOMELI, E. R.; CIRALDO, I.; CUTULI, M.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FISICHELLA, M.; FOTI, A.; HACISALIHOGLU, A.; IAZZI, F.; LA FAUCI, L.; LINARES, R.; LUBIAN, J.; MEDINA, N. H.; MORALLES, M.; OLIVEIRA, J. R. B.; PAKOU, A.; PANDOLA, L.; PINNA, F.; RUSSO, G.; Marcilei Aparecida Guazzelli; SOUKERAS, V.; SOULIOTIS, G.; SPATAFORA, A.; TORRESI, D.; YLIDIRIM, A.; ZAGATTO, V. A. B.© 2021 American Physical Society.Single-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.