Saul Beceiro-Novo
@udc.es
Investigador Ramon y Cajal. Departamento Fisica y ciencias de la tierra
Universidade da Coruña
RESEARCH, TEACHING, or OTHER INTERESTS
Nuclear and High Energy Physics, Radiation, Physics and Astronomy
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
J. Chen, B.P. Kay, C.R. Hoffman, T.L. Tang, I.A. Tolstukhin, D. Bazin, R.S. Lubna, Y. Ayyad, S. Beceiro-Novo, B.J. Coombes,et al.
Elsevier BV
F. Wamers, C. Lehr, J. Marganiec-Gałązka, F. Aksouh, Yu. Aksyutina, H. Álvarez-Pol, L. Atar, T. Aumann, S. Beceiro-Novo, C. A. Bertulani,et al.
American Physical Society (APS)
F. Wamers, C. Lehr, J. Marganiec-Gałązka, F. Aksouh, Yu. Aksyutina, H. Alvarez-Pol, L. Atar, T. Aumann, S. Beceiro-Novo, C. A. Bertulani,et al.
Springer Science and Business Media LLC
AbstractNucleon knockout experiments using beryllium or carbon targets reveal a strong dependence of the quenching factors, i.e., the ratio ($$\\hbox {R}_{\\textrm{s}}$$ R s ) of theoretical to the experimental spectroscopic factors ($$\\hbox {C}^2{\\textrm{S}}$$ C 2 S ), on the proton-neutron asymmetry in the nucleus under study. However, this dependence is greatly reduced when a hydrogen target is used. To understand this phenomenon, exclusive $$^{1}\\text {H}(^{17}\\text {Ne},$$ 1 H ( 17 Ne , $$2\\hbox {p}~^{16}\\text {F})$$ 2 p 16 F ) and inclusive $$^{12}\\text {C}(^{17}\\text {Ne},2\\hbox {p}~^{16}\\text {F})\\hbox {X}$$ 12 C ( 17 Ne , 2 p 16 F ) X , $$^{12}\\text {C}(^{17}\\text {Ne},$$ 12 C ( 17 Ne , $$^{16}\\text {F})\\hbox {X}$$ 16 F ) X as well as $$^{1}\\text {H}(^{17}\\text {Ne},^{16}\\text {F})\\hbox {X}$$ 1 H ( 17 Ne , 16 F ) X (X-denotes undetected reaction products) reactions with $$^{16}\\text {F}$$ 16 F in the ground and excited states were analysed. The longitudinal momentum distribution of $$^{16}{\\textrm{F}}$$ 16 F and the correlations between the detached protons were studied. In the case of the carbon target, there is a significant deviation from the predictions of the eikonal model. The eikonal approximation was used to extract spectroscopic factor values $$\\hbox {C}^2{\\textrm{S}}$$ C 2 S . The experimental $$\\hbox {C}^2\\hbox {S}$$ C 2 S value obtained with C target is markedly lower than that for H target. This is interpreted as rescattering due to simultaneous nucleon knockout from both reaction partners, $$^{17}\\text {Ne}$$ 17 Ne and $$^{12}\\text {C}$$ 12 C .
S. Giraud, J. C. Zamora, R. G. T. Zegers, D. Bazin, Y. Ayyad, S. Bacca, S. Beceiro-Novo, B. A. Brown, A. Carls, J. Chen,et al.
American Physical Society (APS)
For the first time, the $(d,{}^2\\text{He})$ reaction was successfully used in inverse kinematics to extract the Gamow-Teller transition strength in the $\\beta^{+}$ direction from an unstable nucleus. The nucleus studied was $^{14}$O, and the Gamow-Teller transition strength to $^{14}$N was extracted up to an excitation energy of 22 MeV. The measurement of the $(d,{}^2\\text{He})$ reaction in inverse kinematics was made possible by the combination of an active target time projection chamber and a magnetic spectrometer. The data were used to test shell-model and state-of-the-art coupled cluster calculations. Shell-model calculations reproduce the measured Gamow-Teller strength distribution up to about 15 MeV reasonably well, after the application of a phenomenological quenching factor. Coupled-cluster calculation reproduces the full strength distribution well without such quenching, owing to the large model space, the inclusion of strong correlations, and the coupling of the weak interaction to two nucleons through two-body currents. This indicates that such calculations provide a very promising path for answering long-standing questions about the observed quenching of Gamow-Teller strengths in nuclei.
M. Heil, A. Kelić-Heil, L. Bott, T. Almusidi, H. Alvarez-Pol, L. Atar, L. Atkins, T. Aumann, J. Benlliure, K. Boretzky,et al.
Springer Science and Business Media LLC
AbstractWe present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R$$^3$$ 3 B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision $$\\sigma _{\\varDelta E}/{\\varDelta E}$$ σ Δ E / Δ E of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.
J. L. Rodríguez-Sánchez, J. Benlliure, I. Vidaña, H. Lenske, J. Vargas, C. Scheidenberger, H. Alvarez-Pol, J. Atkinson, T. Aumann, Y. Ayyad,et al.
American Physical Society (APS)
The fragment separator FRS has been for the first time used to measure the ( n, p ) and ( p, n )-type isobaric charge-exchange cross sections of stable 112 , 124 Sn isotopes accelerated at 1 A GeV with an uncertainty of 3% and to separate quasi-elastic and inelastic components in the missing-energy spectra of the ejectiles a . The inelastic contribution can be associated to the excitation of isobar ∆(1232) resonances and to the pion emission in s-wave, both in the target and projectile nuclei, while the quasi-elastic contribution is associated to the nuclear spin-isospin response of nucleon-hole excitations. The data lead to interesting results where we observe a clear quenching of the quasi-elastic component and their comparisons to theoretical calculations demonstrate that the baryonic resonances can be excited in the target and projectile nuclei. To go further in this investigation, we propose to study the excitation of baryonic resonances taking advantage of the combination of high-resolving power magnetic spectrometers with the WASA calorimeter. These new measurements will allow us to determine the momenta of the ejectiles and pions emitted in coincidence after the single isobaric charge-exchange collisions, providing us unique opportunities to study the evolution of the baryonic resonance dynamics with the neutron-proton asymmetry through the use of exotic radioactive ion beams.
C. Lehr, F. Wamers, F. Aksouh, Yu. Aksyutina, H. Álvarez-Pol, L. Atar, T. Aumann, S. Beceiro-Novo, C.A. Bertulani, K. Boretzky,et al.
Elsevier BV
A. K. Anthony, C. Y. Niu, R. S. Wang, J. Wieske, K. W. Brown, Z. Chajecki, W. G. Lynch, Y. Ayyad, J. Barney, T. Baumann,et al.
AIP Publishing
A challenge preventing successful inverse kinematics measurements with heavy nuclei that are not fully stripped is identifying and tagging the beam particles. For this purpose, the HEavy ISotope Tagger (HEIST) has been developed. HEIST utilizes two micro-channel plate timing detectors to measure the time-of-flight, a multi-sampling ion chamber to measure energy loss, and a high-purity germanium detector to identify isomer decays and calibrate the isotope identification system. HEIST has successfully identified 198Pb and other nearby nuclei at energies of about 75 MeV/A. In the experiment discussed, a typical cut containing 89% of all 198Pb80+ in the beam had a purity of 86%. We examine the issues of charge state contamination. The observed charge state populations of these ions are presented and, using an adjusted beam energy, are well described by the charge state model GLOBAL.
J. M. Boillos, D. Cortina-Gil, J. Benlliure, J. L. Rodríguez-Sánchez, H. Alvarez-Pol, L. Atar, T. Aumann, V. V. Avdeichikov, S. Beceiro-Novo, D. Bemmerer,et al.
American Physical Society (APS)
We measured 135 cross sections of residual nuclei produced in fragmentation reactions of 12 C, 14 N, and 13 − 16 , 20 , 22 O projectiles impinging on a carbon target at kinetic energies of near 400 A MeV, most of them for the first time, with the R 3 B / LAND setup at the GSI facility in Darmstadt (Germany). The use of this state-of-the-art experimental setup in combination with the inverse kinematics technique gave the full identification in atomic and mass numbers of fragmentation residues with a high precision. The cross sections of these residues were determined with uncertainties below 20% for most of the cases. These data are compared to other previous measurements with stable isotopes and are also used to benchmark different model calculations.
A. Bhattacharyya, Ushasi Datta, A. Rahaman, S. Chakraborty, T. Aumann, S. Beceiro-Novo, K. Boretzky, C. Caesar, B. V. Carlson, W. N. Catford,et al.
American Physical Society (APS)
The measurements of neutron capture cross sections of neutron-rich nuclei are challenging but essential for understanding nucleosynthesis and stellar evolution processes in the explosive burning scenario. In the quest of r -process abundances, according to the neutrino-driven-wind model, light neutron-rich unstable nuclei may play a significant role as seed nuclei that influence the abundance pattern. Hence, experimental data for neutron capture cross sections of neutron-rich nuclei are needed. Coulomb dissociation of radioactive ion beams at intermediate energy is a powerful indirect method for inferring capture cross section. As a test case for validation of the indirect method, the neutron capture cross section ( n , γ ) for C 14 was inferred from the Coulomb dissociation of C 15 at intermediate energy ( 600 A MeV). A comparison between different theoretical approaches and experimental results for the reaction is discussed. We report for the first time experimental reaction cross sections of Na 28 ( n , γ ) Na 29 , Na 29 ( n , γ ) Na 30 , Mg 32 ( n , γ ) Mg 33 , and Al 34 ( n , γ ) Al 35 . The reaction cross sections were inferred indirectly through Coulomb dissociation of Na 29 , 30 , Mg 33 , and Al 35 at incident projectile energies around 400–430 A MeV using the FRS-LAND setup at GSI, Darmstadt. The neutron capture cross sections were obtained from the photoabsorption cross sections with the aid of the detailed balance theorem. The reaction rates for the neutron-rich Na, Mg, Al nuclei at typical r -process temperatures were obtained from the measured ( n , γ ) capture cross sections. The measured neutron capture reaction rates of the neutron-rich nuclei, Na 28 , Na 29 , and Al 34 are significantly lower than those predicted by the Hauser-Feshbach decay model. A similar trend was observed earlier for C 17 and N 19 but in the case of C 14 ( n , γ ) C 15 the trend is opposite. The situation is more complicated when the ground state has a multi-particle-hole configuration. For Mg 32 , the measured cross section is about 40 – 90 % higher than the Hauser-Feshbach prediction.
J L Rodríguez-Sánchez, J Benlliure, E Haettner, C Scheidenberger, J Vargas, Y Ayyad, H Alvarez-Pol, J Atkinson, T Aumann, S Beceiro-Novo,et al.
IOP Publishing
Abstract Isobaric charge-exchange reactions induced by beams of 112Sn have been investigated at the GSI facility using the fragment separator FRS. The high-resolving power of this spectrometer makes it possible to obtain the isobaric charge-exchange cross sections with an uncertainty of 3.5% and to separate quasi-elastic and inelastic contributions in the missing-energy spectra, in which the inelastic component is associated to the in-medium excitation of baryonic resonances such as the Δ resonance. We report on the results obtained for the (p,n) channel excited by using different targets that cover a large range in neutron excess. In addition, we also compare the missing-energy spectra with an intranuclear cascade model coupled to a de-excitation code to investigate the in-medium effects in the production of baryonic resonances.
J L Rodríguez-Sánchez, J Benlliure, E Haettner, C Scheidenberger, J Vargas, Y Ayyad, H Alvarez-Pol, J Atkinson, T Aumann, S Beceiro-Novo,et al.
IOP Publishing
Abstract Isobaric charge-exchange reactions induced by beams of 112Sn have been investigated at the GSI facilities using the fragment separator FRS. The high-resolving power of this spectrometer makes it possible to obtain the isobaric charge-exchange cross sections with an accuracy of 3% and to separate quasi-elastic and inelastic contributions in the missing-energy spectra, in which the inelastic component is associated to the in-medium excitation of baryonic resonances such as the Δ resonance. We report on the results obtained for the (p,n) and (n,p) channels excited by using different targets that cover a large range in neutron excess.
J. S. Randhawa, Y. Ayyad, W. Mittig, Z. Meisel, T. Ahn, S. Aguilar, H. Alvarez-Pol, D. W. Bardayan, D. Bazin, S. Beceiro-Novo,et al.
Physical Review Letters American Physical Society (APS)
I. Syndikus, M. Petri, A.O. Macchiavelli, S. Paschalis, C.A. Bertulani, T. Aumann, H. Alvarez-Pol, L. Atar, S. Beceiro-Novo, J. Benlliure,et al.
Elsevier BV
D. Bazin, T. Ahn, Y. Ayyad, S. Beceiro-Novo, A.O. Macchiavelli, W. Mittig, and J.S. Randhawa
Elsevier BV
J.L. Rodríguez-Sánchez, J. Benlliure, I. Vidaña, H. Lenske, C. Scheidenberger, J. Vargas, H. Alvarez-Pol, J. Atkinson, T. Aumann, Y. Ayyad,et al.
Elsevier BV
Y. Ayyad, B. Olaizola, W. Mittig, G. Potel, V. Zelevinsky, M. Horoi, S. Beceiro-Novo, M. Alcorta, C. Andreoiu, T. Ahn,et al.
American Physical Society (APS)
This corrects the article DOI: 10.1103/PhysRevLett.123.082501.
Y. Ayyad, N. Abgrall, T. Ahn, H. Álvarez-Pol, D. Bazin, S. Beceiro-Novo, L. Carpenter, R.J. Cooper, M. Cortesi, A.O. Macchiavelli,et al.
Elsevier BV
J.S. Randhawa, M. Cortesi, Y. Ayyad, W. Mittig, T. Ahn, D. Bazin, S. Beceiro-Novo, L. Carpenter, K.J. Cook, M. Dasgupta,et al.
Elsevier BV
Y. Ayyad, B. Olaizola, W. Mittig, G. Potel, V. Zelevinsky, M. Horoi, S. Beceiro-Novo, M. Alcorta, C. Andreoiu, T. Ahn,et al.
American Physical Society (APS)
The elusive β^{-}p^{+} decay was observed in ^{11}Be by directly measuring the emitted protons and their energy distribution for the first time with the prototype Active Target Time Projection Chamber in an experiment performed at ISAC-TRIUMF. The measured β^{-}p^{+} branching ratio is orders of magnitude larger than any previous theoretical model predicted. This can be explained by the presence of a narrow resonance in ^{11}B above the proton separation energy.
M. Holl, V. Panin, H. Alvarez-Pol, L. Atar, T. Aumann, S. Beceiro-Novo, J. Benlliure, C.A. Bertulani, J.M. Boillos, K. Boretzky,et al.
Elsevier BV
G. Ribeiro, E. Nácher, O. Tengblad, P. Díaz Fernández, Y. Aksyutina, H. Alvarez-Pol, L. Atar, T. Aumann, V. Avdeichikov, S. Beceiro-Novo,et al.
American Physical Society (APS)
The neutron-unbound isotope Be-13 has been studied in several experiments using different reactions, different projectile energies, and different experimental setups. There is, however, no real consensus in the interpretation of the data, in particular concerning the structure of the low-lying excited states. Gathering new experimental information, which may reveal the Be-13 structure, is a challenge, particularly in light of its bridging role between Be-12, where the N = 8 neutron shell breaks down, and the Borromean halo nucleus Be-14. The purpose of the present study is to investigate the role of bound excited states in the reaction product Be-12 after proton knockout from B-14, by measuring coincidences between Be-12, neutrons, and gamma rays originating from de-excitation of states fed by neutron decay of Be-13. The Be-13 isotopes were produced in proton knockout from a 400 MeV/nucleon B-14 beam impinging on a CH2 target. The Be-12-n relative-energy spectrum d sigma/dE(fn) was obtained from coincidences between Be-12(g.s.) and a neutron, and also as threefold coincidences by adding gamma rays, from the de-excitation of excited states in Be-12. Neutron decay from the first 5/2(+) state in Be-13 to the 2(+) state in Be-12 at 2.11 MeV is confirmed. An energy independence of the proton-knockout mechanism is found from a comparison with data taken with a 35 MeV/nucleon B-14 beam. A low-lying p-wave resonance in Be-13(1/2(-)) is confirmed by comparing proton- and neutron-knockout data from B-14 and Be-14.
C. Morse, E.A. McCutchan, H. Iwasaki, C.J. Lister, V.M. Bader, D. Bazin, S. Beceiro Novo, P. Chowdhury, A. Gade, T.D. Johnson,et al.
Elsevier BV
A. Revel, F. M. Marqués, O. Sorlin, T. Aumann, C. Caesar, M. Holl, V. Panin, M. Vandebrouck, F. Wamers, H. Alvarez-Pol,et al.
American Physical Society (APS)
The emission of neutron pairs from the neutron-rich N=12 isotones ^{18}C and ^{20}O has been studied by high-energy nucleon knockout from ^{19}N and ^{21}O secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay ^{19}N(-1p)^{18}C^{*}→^{16}C+n+n is clearly dominated by direct pair emission. The two-neutron correlation strength, the largest ever observed, suggests the predominance of a ^{14}C core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay ^{21}O(-1n)^{20}O^{*}→^{18}O+n+n, attributed to its formation through the knockout of a deeply bound neutron that breaks the ^{16}O core and reduces the number of pairs.
E.C. Pollacco, G.F. Grinyer, F. Abu-Nimeh, T. Ahn, S. Anvar, A. Arokiaraj, Y. Ayyad, H. Baba, M. Babo, P. Baron,et al.
Elsevier BV