Search

Your search keyword '"De Oliveira-Santos, F"' showing total 14 results
Start Over Author "De Oliveira-Santos, F" Topic nuclear experiment
14 results on '"De Oliveira-Santos, F"'

1. N=16 magicity revealed at the proton drip-line through the study of 35Ca

Author

Lalanne, L, Sorlin, O, Poves, A, Assié, M, Hammache, F, Koyama, S, Suzuki, D, Flavigny, F, Girard-Alcindor, V, Lemasson, A, Matta, A, Roger, T, Beaumel, D, Blumenfeld, Y, Brown, B.A, de Oliveira Santos, F, Delaunay, F, de Séréville, N, Franchoo, S, Gibelin, J, Guillot, J, Kamalou, O, Kitamura, N, Lapoux, V, Mauss, B, Morfouace, P, Pancin, J, Saito, T.Y, Stodel, C, Thomas, J-C, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay

Subjects
FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

International audience; The last proton bound calcium isotope $^{35}$Ca has been studied for the first time, using the $^{37}$Ca($p, t$)$^{35}$Ca two neutron transfer reaction. The radioactive $^{37}$Ca nuclei, produced by the LISE spectrometer at GANIL, interacted with the protons of the liquid hydrogen target CRYPTA, to produce tritons $t$ that were detected in the MUST2 detector array, in coincidence with the heavy residues Ca or Ar. The atomic mass of $^{35}$Ca and the energy of its first 3/2$^+$ state are reported. A large $N=16$ gap of 4.61(11) MeV is deduced from the mass measurement, which together with other measured properties, makes $^{36}$Ca a doubly-magic nucleus. The $N = 16$ shell gaps in $^{36}$Ca and $^{24}$O are of similar amplitude, at both edges of the valley of stability. This feature is discussed in terms of nuclear forces involved, within state-of-the-art shell model calculations. Even though the global agreement with data is quite convincing, the calculations underestimate the size of the $N = 16$ gap in 36Ca by 840(110) keV.

Published
2023

2. Border of the island of inversion: Unbound states in 29 Ne

Author

Holl, M., Lindberg, S., Heinz, A., Kondo, Y., Nakamura, T., Tostevin, J. A., Wang, H., Nilsson, T., Achouri, N. L., Al Falou, H., Atar, L., Aumann, T., Baba, H., Boretzky, K., Caesar, C., Calvet, D., Chae, H., Chiga, N., Corsi, A., Crawford, H. L., Delaunay, F., Delbart, A., Deshayes, Q., D��az Fern��ndez, P., Dombr��di, Z., Douma, C. A., Elekes, Z., Fallon, P., Ga��pari��, I., Gheller, J.-M., Gibelin, J., Gillibert, A., Harakeh, M. N., Hirayama, A., Hoffman, C. R., Horvat, A., Horv��th, ��., Hwang, J. W., Isobe, T., Kahlbow, J., Kalantar-Nayestanaki, N., Kawase, S., Kim, S., Kisamori, K., Kobayashi, T., K��rper, D., Koyama, S., Kuti, I., Lapoux, V., Marqu��s, F. M., Masuoka, S., Mayer, J., Miki, K., Murakami, T., Najafi, M., Nakano, K., Nakatsuka, N., Obertelli, A., de Oliveira Santos, F., Orr, N. A., Otsu, H., Ozaki, T., Panin, V., Paschalis, S., Revel, A., Rossi, D., Saito, A. T., Saito, T. Y., Sasano, M., Sato, H., Satou, Y., Scheit, H., Schindler, F., Schrock, P., Shikata, M., Shimizu, Y., Simon, H., Sohler, D., Sorlin, O., Stuhl, L., Takeuchi, S., Tanaka, M., Thoennessen, M., T��rnqvist, H., Togano, Y., Tomai, T., Tscheuschner, J., Tsubota, J., Uesaka, T., Yang, Z., Yasuda, M., Yoneda, K., Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), SAMURAI21, Research unit Nuclear & Hadron Physics, and Nuclear Energy

Subjects
Physics, FOS: Physical sciences, Nuclear structure, direct reactions, radioactive beams, ddc:530, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

The nucleus $^{29}$Ne is situated at the border of the island of inversion. Despite significant efforts, no bound low-lying intruder $f_{7/2}$-state, which would place $^{29}$Ne firmly inside the island of inversion, has yet been observed. Here, the first investigation of unbound states of $^{29}$Ne is reported. The states were populated in $^{30}\mathrm{Ne}(p,pn)$ and $^{30}\mathrm{Na}(p,2p)$ reactions at a beam energy of around $230$ MeV/nucleon, and analyzed in terms of their resonance properties, partial cross sections and momentum distributions. The momentum distributions are compared to calculations using the eikonal, direct reaction model, allowing $\ell$-assignments for the observed states. The lowest-lying resonance at an excitation energy of 1.48(4) MeV shows clear signs of a significant $\ell$=3-component, giving first evidence for $f_{7/2}$ single particle strength in $^{29}$Ne. The excitation energies and strengths of the observed states are compared to shell-model calculations using the sdpf-u-mix interaction, Comment: 12 pages, 14 figures, accepted for publication in Physical Review C

Published
2022
Full Text
View/download PDF

3. Narrow resonances in the continuum of the unbound nucleus $^{15}$F

Author

Girard-Alcindor, V., Mercenne, A., Stefan, I., de Oliveira Santos, F., Michel, N., Płoszajczak, M., Assié, M., Lemasson, A., Clément, E., Flavigny, F., Matta, A., Ramos, D., Rejmund, M., Dudouet, J., Ackermann, D., Adsley, P., Assunção, M., Bastin, B., Beaumel, D., Benzoni, G., Borcea, R., Boston, A.J., Cáceres, L., Cederwall, B., Celikovic, I., Chudoba, V., Ciemala, M., Collado, J., Crespi, F.C.L., D'Agata, G., De France, G., Delaunay, F., Diget, C., Domingo-Pardo, C., Eberth, J., Fougères, C., Franchoo, S., Galtarossa, F., Georgiadou, A., Gibelin, J., Giraud, S., González, V., Goyal, N., Gottardo, A., Goupil, J., Grévy, S., Guimaraes, V., Hammache, F., Harkness-Brennan, L.J., Hess, H., Oliver, D.S. Judson, Kamalou, O., Kameneyero, A., Kiener, J., Korten, W., Koyama, S., Labiche, M., Lalanne, L., Lapoux, V., Leblond, S., Lefevre, A., Lenain, C., Leoni, S., Li, H., Lopez-Martens, A., Maj, A., Matea, I., Menegazzo, R., Mengoni, D., Meyer, A., Million, B., Monteagudo, B., Morfouace, P., Mrazek, J., Niikura, M., Piot, J., Podolyak, Zs., Portail, C., Pullia, A., Quintana, B., Recchia, F., Reiter, P., Rezynkina, K., Roger, T., Rojo, J.S., Rotaru, F., Salsac, M.D., Benitez, A.M. Sánchez, Sanchis, E., Şenyigit, M., De Séréville, N., Siciliano, M., Simpson, J., Sohler, D., Sorlin, O., Stanoiu, M., Stodel, C., Suzuki, D., Theisen, C., Thomas, J.C., Ujic, P., Valiente-Dobón, J.J., Zielińska, M., Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Theory (nucl-th), Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

The structure of the unbound $^{15}$F nucleus is investigated using the inverse kinematics resonant scattering of a radioactive $^{14}$O beam impinging on a CH$_2$ target. The analysis of $^{1}$H($^{14}$O,p)$^{14}$O and $^{1}$H($^{14}$O,2p)$^{13}$N reactions allowed the confirmation of the previously observed narrow $1/2^{-}$ resonance, near the two-proton decay threshold, and the identification of two new narrow 5/2$^{-}$ and 3/2$^{-}$ resonances. The newly observed levels decay by 1p emission to the ground of $^{14}$O, and by sequential 2p emission to the ground state (g.s.) of $^{13}$N via the $1^-$ resonance of $^{14}$O. Gamow shell model (GSM) analysis of the experimental data suggests that the wave functions of the 5/2$^{-}$ and 3/2$^{-}$ resonances may be collectivized by the continuum coupling to nearby 2p- and 1p- decay channels. The observed excitation function $^{1}$H($^{14}$O,p)$^{14}$O and resonance spectrum in $^{15}$F are well reproduced in the unified framework of the GSM., Comment: 7 pages, 4 figures

Published
2021

4. Probing nuclear forces beyond the nuclear drip line: the cases of 16F and 15F: a tribute to Mahir Hussein

Author

Girard-Alcindor, V, Stefan, I, de Oliveira Santos, F, Sorlin, O, Ackermann, D, Adsley, P, Angélique, J C, Assié, M, Assunção, M, Beaumel, D, Berthoumieux, E, Borcea, R, Cáceres, L, Čeliković, Igor T., Ciemala, M, Chudoba, V, D’Agata, G, de Grancey, F, Dumitru, G, Flavigny, F, Fougères, C, Franchoo, S, Georgiadou, A, Goyal, N, Grévy, S, Guillot, J, Guimaraes, V, Hammache, F, Kamalou, O, Kiener, J, Koyama, S, Lalanne, L, Lapoux, V, Matea, I, Matta, A, Meyer, A, Michel, N, Morfouace, P, Mrazek, J, Negoita, F, Niikura, M, Pantelica, D, Perrot, L, Petrone, C, Piot, J, Portail, C, Roger, T, Rotaru, F, Sánchez Benítez, A M, de Séréville, N, Stanoiu, M, Stodel, C, Subotić, Krunoslav M., Suzuki, D, Tatischeff, V, Thomas, J C, Ujić, Predrag, and Verney, D

Subjects
Nuclear Theory, Nuclear Experiment
Abstract

The unbound proton-rich nuclei 16F and 15F are investigated experimentally and theoretically. Several experiments using the resonant elastic scattering method were performed at GANIL with radioactive beams to determine the properties of the low lying states of these nuclei. Strong asymmetry between 16F–16N and 15F–15C mirror nuclei is observed. The strength of the nucleon- nucleon effective interaction involving the loosely bound proton in the s1 / 2 orbit is significantly modified with respect to their mirror nuclei 16N and 15C. The reduction of the effective interaction is estimated by calculating the interaction energies with a schematic zero-range force. It is found that, after correcting for the effects due to changes in the radial distribution of the single-particle wave functions, the mirror symmetry of the n- p interaction is preserved between 16F and 16N, while a difference of 63% is measured between the p- p versus n- n interactions in the second excited state of 15F and 15C nuclei. Several explanations are proposed. © 2021, The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature. Part of a collection: Cluster Structure and Dynamics of Nuclei - A Tribute to Mahir Hussein. [] Preprint version available at: [https://arxiv.org/abs/2101.02132]

Published
2021

5. Evaluation of the $^{35}\mathrm{K}(p,\gamma)^{36}\mathrm{Ca}$ reaction rate using the $^{37}\mathrm{Ca}(p,d)^{36}\mathrm{Ca}$ transfer reaction

Author

Lalanne, L., Sorlin, O., Assié, M., Hammache, F., de Séréville, N., Koyama, S., Suzuki, D., Flavigny, F., Beaumel, D., Blumenfeld, Y., Brown, B.A., de Oliveira Santos, F., Delaunay, F., Franchoo, S., Gibelin, J., Girard-Alcindor, V., Guillot, J., Kamalou, O., Kitamura, N., Lapoux, V., Lemasson, A., Matta, A., Mauss, B., Morfouace, P., Niikura, M., Pancin, J., Poves, A., Roger, T., Saito, T., Stodel, C., Thomas, J-C., Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear Astrophysics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Background: A recent sensitivity study has shown that the K35(p,γ)Ca36 reaction is one of the ten (p,γ) reaction rates that could significantly impact the shape of the calculated x-ray burst light curve. Its reaction rate used up to now in type I x-ray burst calculations was estimated using an old measurement for the mass of Ca36 and theoretical predictions for the partial decay widths of the first 2+ resonance with arbitrary uncertainties. Purpose: In this work, we propose to reinvestigate the K35(p,γ)Ca36 reaction rate, as well as related uncertainties, by determining the energies and decay branching ratios of Ca36 levels, within the Gamow window of x-ray bursts, in the 0.5 to 2 GK temperature range. Method: These properties were studied by means of the one-neutron pickup transfer reaction Ca37(p,d)Ca36 in inverse kinematics using a radioactive beam of Ca37 at 48 MeV nucleon−1. The experiment was performed at the GANIL facility using the liquid hydrogen target CRYPTA, the MUST2 charged particle detector array for the detection of the light charged particles, and a zero degree detection system for the outgoing heavy recoil nuclei. Results: The atomic mass of Ca36 is confirmed and new resonances have been proposed together with their proton decay branching ratios. This spectroscopic information, used in combination with very recent theoretical predictions for the γ-decay width, were used to calculate the K35(p,γ)Ca36 reaction rate. The recommended rate of the present work was obtained within a uncertainty factor of 2 at 1σ. This is consistent with the previous estimate in the x-ray burst temperature range. A large increase of the reaction rate was found at higher temperatures due to two newly discovered resonances. Conclusions: The K35(p,γ)Ca36 thermonuclear reaction rate is now well constrained by the present work in a broad range of temperatures covering those relevant to type I x-ray bursts. Our results show that the K35(p,γ)Ca36 reaction does not affect the shape of the x-ray burst light curve, and that it can be removed from the list of the few influential proton radiative captures reactions having a strong impact on the light curve.

Published
2021
Full Text
View/download PDF

6. Extending the Southern Shore of the Island of Inversion to F28

Author

Revel, A., Sorlin, O., Marqués, F. M., Kondo, Y., Kahlbow, J., Nakamura, T., Orr, N. A., Nowacki, F., Tostevin, J. A., Yuan, C. X., Achouri, N. L., Al Falou, H., Atar, L., Aumann, T., Baba, H., Boretzky, K., Caesar, C., Calvet, D., Chae, H., Chiga, N., Corsi, A., Crawford, H. L., Delaunay, F., Delbart, A., Deshayes, Q., Dombrádi, Z., Douma, C. A., Elekes, Z., Fallon, P., Gašparić, Igor, Gheller, J.-M., Gibelin, J., Gillibert, A., Harakeh, M. N., He, W., Hirayama, A., Hoffman, C. R., Holl, M., Horvat, A., Horváth, Á., Hwang, J. W., Isobe, T., Kalantar-Nayestanaki, N., Kawase, S., Kim, S., Kisamori, K., Kobayashi, T., Körper, D., Koyama, S., Kuti, I., Lapoux, V., Lindberg, S., Masuoka, S., Mayer, J., Miki, K., Murakami, T., Najafi, M., Nakano, K., Nakatsuka, N., Nilsson, T., Obertelli, A., de Oliveira Santos, F., Otsu, H., Ozaki, T., Panin, V., Paschalis, S., Rossi, D., Saito, A. T., Saito, T., Sasano, M., Sato, H., Satou, Y., Scheit, H., Schindler, F., Schrock, P., Shikata, M., Shimizu, Y., Simon, H., Sohler, D., Stuhl, L., Takeuchi, S., Tanaka, M., Thoennessen, M., Törnqvist, H., Togano, Y., Tomai, T., Tscheuschner, J., Tsubota, J., Uesaka, T., Yang, Z., Yasuda, M., Yoneda, K., and SAMURAI21 collaboration

Subjects
Nuclear Theory, Binding energy and masses, Direct reactions, Energy levels and level densities, Models and methods for nuclear reactions, Rare and new isotopes, Nuclear Experiment
Abstract

Detailed spectroscopy of the neutron-unbound nucleus F28 has been performed for the first time following proton/neutron removal from Ne29/F29 beams at energies around 230 MeV/nucleon. The invariant- mass spectra were reconstructed for both the F(*)27+n and F(*)26+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the F28 ground state, with Sn(F28)=-199(6) keV, while analysis of the 2n decay channel allowed a considerably improved Sn(F27)=1620(60) keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of F28. Importantly, in the case of the ground state, the reconstructed F27+n momentum distribution following neutron removal from F29 indicates that it arises mainly from the 1p3/2 neutron intruder configuration. This demonstrates that the island of inversion around N=20 includes F28, and most probably F29, and suggests that O28 is not doubly magic.

Published
2020
Full Text
View/download PDF

7. Effective proton-neutron interaction near the drip line from unbound states in 25,26 F

Author

Vandebrouck, M., Lepailleur, A., Sorlin, O, Aumann, T., Caesar, C., Holl, M., Panin, V., Wamers, F., Stroberg, S. R., Holt, J. D., De Oliveira Santos, F., Alvarez-Pol, H., Atar, L., Avdeichikov, V., Beceiro-Novo, S., Bemmerer, D., Benlliure, J., Bertulani, C. A., Bogner, S. K., Boillos, J. M., Boretzky, K., Borge, M. J. G., Caamaño, M., Casarejos, E., Catford, W, Cederkäll, J., Chartier, M., Chulkov, L. V., Cortina-Gil, D, Cravo, E., Crespo, R., Datta Pramanik, U., Díaz Fernández, P., Dillmann, I., Elekes, Z., Enders, J., Ershova, O., Estradé, A., Farinon, F., Fraile, L. M., Freer, M., Galaviz, D., Geissel, H, Gernhäuser, R., Gibelin, J., Golubev, P., Göbel, K., Hagdahl, J., Paschalis, S., and Petri, M.

Subjects
Nuclear Theory, Nuclear Experiment
Abstract

Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The F26 nucleus, composed of a deeply bound π0d5/2 proton and an unbound ν0d3/2 neutron on top of an O24 core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a Jπ=11+-41+ multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The Jπ=11+,21+,41+ bound states have been determined, and only a clear identification of the Jπ=31+ is missing. Purpose: We wish to complete the study of the Jπ=11+-41+ multiplet in F26, by studying the energy and width of the Jπ=31+ unbound state. The method was first validated by the study of unbound states in F25, for which resonances were already observed in a previous experiment. Method: Radioactive beams of Ne26 and Ne27, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in F25 and F26 via one-proton knockout reactions on a CH2 target, located at the object focal point of the R3B/LAND setup. The detection of emitted γ rays and neutrons, added to the reconstruction of the momentum vector of the A-1 nuclei, allowed the determination of the energy of three unbound states in F25 and two in F26. Results: Based on its width and decay properties, the first unbound state in F25, at the relative energy of 49(9) keV, is proposed to be a Jπ=1/2- arising from a p1/2 proton-hole state. In F26, the first resonance at 323(33) keV is proposed to be the Jπ=31+ member of the Jπ=11+-41+ multiplet. Energies of observed states in F25,26 have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton-neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of F26.

Published
2017

8. Effective proton-neutron interaction near the drip line from unbound states in $^{25,26}$F

Author

Vandebrouck, M., Lepailleur, A., Sorlin, O., Aumann, T., Caesar, C., Holl, M., Panin, V., Wamers, F., Stroberg, S. R., Holt, J. D., de Oliveira Santos, F., Alvarez-Pol, H., Atar, L., Avdeichikov, V., Beceiro-Novo, S., Bemmerer, D., Benlliure, J., Bertulani, C. A., Bogner, S. K., Boillos, J. M., Boretzky, K., Borge, M. J. G., Caamaño, M., Casarejos, E., Catford, W., Cederkäll, J., Chartier, M., Chulkov, L., Cortina-Gil, D., Cravo, E., Crespo, R., Datta Pramanik, U., Díaz Fernández, P., Dillmann, I., Elekes, Z., Enders, J., Ershova, O., Estradé, A., Farinon, F., Fraile, L. M., Freer, M., Galaviz, D., Geissel, H., Gernhäuser, R., Gibelin, J., Golubev, P., Göbel, K., Hagdahl, J., Heftrich, T., Heil, M., Heine, M. (Marcel), Heinz, A., Henriques, A., Hergert, H., Hufnagel, A., Ignatov, A., Johansson, H. T., Jonson, B., Kahlbow, J., Kalantar-Nayestanaki, N., Kanungo, R., Kelic-Heil, A., Knyazev, A., Kröll, T., Kurz, N., Labiche, M., Langer, C., Le Bleis, T., Lemmon, R., Lindberg, S., Machado, J., Marganiec, J., Marqués, F. M., Movsesyan, A., Nacher, E., Najafi, M., Nikolskii, E., Nilsson, T., Nociforo, C., Paschalis, S., Perea, A., Petri, M., Pietri, S., Plag, R., Reifarth, R., Ribeiro, G., Rigollet, C., Röder, M., Rossi, D., Savran, D., Scheit, H., Schwenk, A., Simon, H., Syndikus, I., Taylor, J. T., Tengblad, O., Thies, R., Togano, Y., Velho, P., Volkov, V., Wagner, A., Weick, H., Wheldon, C., Wilson, G., Winfield, J. S., Woods, P., Yakorev, D., Zhukov, M., Zilges, A., Zuber, K., Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), R3B Collaboration, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
21.10.-k, Nuclear Theory, Aucun, Coulomb dissociation radioactive beam, FOS: Physical sciences, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, 27.30.+t, 25.60.-t, 29.30.Hs
Abstract

Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The $^{26}$F nucleus, composed of a deeply bound $\pi0d\_{5/2}$ proton and an unbound $\nu0d\_{3/2}$ neutron on top of an $^{24}$O core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a $J^{\pi} = 1^{+}\_1 - 4^{+}\_1$ multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The $J^{\pi} = 1^{+}\_1, 2^{+}\_1,4^{+}\_1$ bound states have been determined, and only a clear identification of the $J^{\pi} =3^{+}\_1$ is missing.Purpose: We wish to complete the study of the $J^{\pi} = 1^{+}\_1 - 4^{+}\_1$ multiplet in $^{26}$F, by studying the energy and width of the $J^{\pi} =3^{+}\_1$ unbound state. The method was firstly validated by the study of unbound states in $^{25}$F, for which resonances were already observed in a previous experiment.Method: Radioactive beams of $^{26}$Ne and $^{27}$Ne, produced at about $440A$\,MeV by the FRagment Separator at the GSI facility, were used to populate unbound states in $^{25}$F and $^{26}$F via one-proton knockout reactions on a CH$\_2$ target, located at the object focal point of the R$^3$B/LAND setup. The detection of emitted $\gamma$-rays and neutrons, added to the reconstruction of the momentum vector of the $A-1$ nuclei, allowed the determination of the energy of three unbound states in $^{25}$F and two in $^{26}$F. Results: Based on its width and decay properties, the first unbound state in $^{25}$F is proposed to be a $J^{\pi} = 1/2^-$ arising from a $p\_{1/2}$ proton-hole state. In $^{26}$F, the first resonance at 323(33)~keV is proposed to be the $J^{\pi} =3^{+}\_1$ member of the $J^{\pi} = 1^{+}\_1 - 4^{+}\_1$ multiplet. Energies of observed states in $^{25,26}$F have been compared to calculations using the independent-particle shell model, a phenomenological shell-model, and the ab initio valence-space in-medium similarity renormalization group method.Conclusions: The deduced effective proton-neutron interaction is weakened by about 30-40\% in comparison to the models, pointing to the need of implementing the role of the continuum in theoretical descriptions, or to a wrong determination of the atomic mass of $^{26}$F., Comment: 14 pages, 7 figures, 3 tables, submitted to PRC

Published
2017
Full Text
View/download PDF

9. Second 0+ state of unbound $^{12}$O: Scaling of mirror asymmetry

Author

Suzuki, D., Iwasaki, H., Beaumel, D., Assié, M., Baba, H., Blumenfeld, Y., De Oliveira Santos, F., De Séréville, N., Drouart, A., Franchoo, S., Gibelin, J., Gillibert, A., Giron, S., Grévy, S., Guillot, J., Hackstein, M., Hammache, F., Keeley, N., Lapoux, V., Maréchal, F., Matta, A., Michimasa, S., Nalpas, L., Naqvi, F., Okamura, H., Otsu, H., Pancin, J., Pang, D. Y., Perrot, L., Petrache, C. M., Pollacco, E., Ramus, A., Rother, W., Roussel-Chomaz, P., Sakurai, H., Scarpaci, J.-A., Sorlin, O., Srivastava, P. C., Stefan, I., Stodel, C., Tanimura, Y., Terashima, S., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département de Physique Nucléaire (ex SPhN) (DPHN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CSNSM SNO, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM)

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

Expérience GANIL/LISE; International audience; The unbound O12 nucleus was studied via the two-neutron transfer (p,t) reaction in inverse kinematics using a radioactive O14 beam at 51 MeV/u. Excitation energy spectra and differential cross sections were deduced by the missing mass method using MUST2 telescopes. We achieved much higher statistics compared to the previous experiments of O12, which allowed accurate determination of resonance energy and unambiguous spin and parity assignment. The O12 resonance previously reported using the same reaction was confirmed at an excitation energy of 1.62±0.03(stat.)±0.10(syst.). MeV and assigned spin and parity of 0+ from a distorted-wave Born approximation analysis of the differential cross sections. Mirror symmetry of O12 with respect to its neutron-rich partner Be12 is discussed from the energy difference of the second 0+ states. In addition, from systematics of known 0+ states, a distinct correlation is revealed between the mirror energy difference and the binding energy after carrying out a scaling with the mass and the charge. We show that the mirror energy difference of the observed 0+ state of O12 is highly deviated from the systematic trend of deeply bound nuclei and in line with the scaling relation found for weakly bound nuclei with a substantial 2s1/2 component. The importance of the scaling of mirror asymmetry is discussed in the context of ab initio calculations near the drip lines and universality of few-body quantum systems.

Published
2016
Full Text
View/download PDF

10. In-Beam Gamma-Ray Spectroscopy of the Neutron-Rich Nitrogen Isotopes N19-22

Author

Sohler, D, Stanoiu, M, Dombradi, Z, Azaiez, F, Brown, B A, Saint-Laurent, M G, Sorlin, O, Penionzhkevich, Y E, Achouri, N L, Angelique, J C, Belleguic, M, Borcea, C, Bourgeois, C, Daugas, J M, De Oliveira-Santos, F, Dlouhy, Z, Donzaud, C, Duprat, J, Elekes, Z, Grevy, S, Guillemaud-Mueller, D, Ibrahim, F, Leenhardt, S, Lewitowicz, M, Lopez-Jimenez, M J, Lukyanov, S M, Mittig, W, Mrazek, J, Negoita, F, Podolyak, Z, Porquet, M G, Pougheon, F, Roussel-Chomaz, P, Savajols, H, Sletten, G, Sobolev, Y, Stodel, C, and Timar, J

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Nuclear Experiment
Abstract

The structure of N19-22 nuclei was investigated by means of in-beam gamma-ray spectroscopic technique using fragmentation reactions of both stable and radioactive beams. Based on particle-gamma and particle-gamma gamma coincidence data, level schemes are constructed for the neutron-rich nitrogen nuclei. The experimental results are compared with shell model calculations. The strength of the N=14 and Z=8 shell closures and the weakening of the shell model interaction WBT are discussed.

Published
2008

11. First isomeric quadrupole moment measured in fragmentation reactions: The case of Fe-61(m)(9/2(+))

Author

Vermeulen, Nele, Chamoli, SK, Daugas, JM, Hass, M, Balabanski, DL, Delaroche, JP, de Oliveira-Santos, F, Georgiev, G, Girod, M, Goldring, G, Goutte, H, Grevy, S, Matea, I, Morel, P, Singh, BS Nara, Penionzkevich, Yu-E, Perrot, L, Perru, O, Peru, S, Roig, O, Sarazin, F, Simpson, GS, Sobolev, Yu, Stefan, I, Stodel, C, Yordanov, DT, and Neyens, Gerda

Subjects
polarization, Nuclear Theory, deformation, projectile fragmentation, fusion-evaporation reactions, exotic nuclei, isomer g-factor, neutron, 61Fe 9/2+ isomer, TDPAD, heavy-ion, Nuclear Experiment, nuclides, yrast decay schemes, fe-57, isotopes
Abstract

This paper demonstrates the feasibility of quadrupole moment measurements on isomeric levels populated in projectile fragmentation reactions. The neutron-rich Fe-61(9/2(+)) [E-*= 861 keV, T-1/2= 239(5) ns] isomer was produced and spin aligned by the intermediate energy fragmentation of a Ni-64 beam and implanted in a Cd single crystal. Its spectroscopic quadrupole moment Q(s)=41(6) e fm(2) agrees with mean-field based calculations using the finite-range Gogny force, suggesting a moderately deformed shape characterized by an intrinsic charge quadrupole moment Q(0)=-85 e fm(2) or Q(0)=+115 e fm(2). The present measurement paves the way for future determinations of isomeric quadrupole moments in more exotic nuclei. ispartof: Physical Review C, Nuclear physics vol:75 issue:5 pages:1-4 status: published

Published
2007

12. Search for neutron excitations across the N=20 shell gap in Ne25-29

Author

Belleguic, M, Azaiez, F, Dombradi, Z, Sohler, D, Lopez-Jimenez, MJ, Otsuka, Taka, Saint-Laurent, MG, Sorlin, O, Stanoiu, M, Utsuno, Y, Penionzhkevich, YE, Achouri, NL, Angelique, JC, Borcea, C, Bourgeois, C, Daugas, JM, De Oliveira-Santos, F, Dlouhy, Z, Donzaud, C, Duprat, J, Elekes, Z, Grevy, S, Guillemaud-Mueller, D, Leenhardt, S, Lewitowicz, M, Lukyanov, SM, Mittig, W, Porquet, MG, Pougheon, F, Roussel-Chomaz, P, Savajols, H, Sobolev, Y, Stodel, C, and Timar, J

Subjects
Nuclear Theory, Nuclear Experiment
Abstract

Nuclear structure of the neutron rich 25 − 29 Ne nuclei has been investigated through the in-beam γ -ray spectroscopy technique using fragmentation reactions of both stable and radioactive beams. Level schemes have been deduced for these Ne isotopes. In order to examine the importance of intruder fp configurations, they are compared to shell model calculations performed either in the restricted sd or in the larger sdpf valence space. The 25 , 26 Ne and 27 Ne nuclei were found to be in agreement with the sd shell model calculations, whereas 28 Ne exhibits signatures of the intruder fp shell contribution ispartof: Physical Review C, Nuclear Physics vol:72 issue:5 status: published

Published
2005

13. Magnetic moment of the fragmentation-aligned $^{61}$Fe (9/$2^+$) isomer

Author

Matea, I, Georgiev, G, Dougas, J M, Hass, M, Neyens, G, Astabatyan, R A, Baby, L T, Balabanski, D L, Bélier, G, Borremans, D, Chappert, F, Girod, M, Goldring, G, Goutte, H, Himpe, P, Lewitowicz, Lukyanov, S, Méot, V, De Oliveira-Santos, F, Penionzhkevich, Yu E, Porquet, M G, Roig, O, Sawicka, M, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
21.10.Ky, 21.60.-n, 23.20.En, 27.50.+e, FOS: Physical sciences, Nuclear Experiment (nucl-ex), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Nuclear Physics
Abstract

We report on the g factor measurement of the isomer in $^{61}Fe$ ($E^{*}=861 keV$). The isomer was produced and spin-aligned via a projectile-fragmentation reaction at intermediate energy, the Time Dependent Perturbed Angular Distribution (TDPAD) method being used for the measurement of the g factor. For the first time, due to significant improvements of the experimental technique, an appreciable residual alignment of the isomer has been observed, allowing a precise determination of its g factor: $g=-0.229(2)$. Comparison of the experimental g factor with shell-model and mean field calculations confirms the $9/2^+$ spin and parity assignments and suggests the onset of deformation due to the intrusion of Nilsson orbitals emerging from the $\nu g_{9/2}$., Comment: 4 figures. Submitted to Phys. Rev. Lett

Published
2004
Full Text
View/download PDF

14. Coupling effects in the elastic scattering of $^{6}$He on $^{12}$C

Author

Lapoux, V., Alamanos, N., Auger, F., Fekou-Youmbi, V., Gillibert, A., Marie, F., Ottini-Hustache, S., Sida, J.-L., Khoa, D.T., Blumenfeld, Y., Marechal, F., Scarpaci, J.-A., Suomijarvi, T., Kelley, J.H., Casandjian, J.M., Chartier, M., Cortina-Gil, M.D., Mac Cormick, M., Mittig, W., De Oliveira Santos, F., Ostrowski, A.N., Roussel-Chomaz, P., Kemper, K.W., Orr, N.A., Winfield, J.S., Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Département Recherches Subatomiques (DRS-IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
nuclear optical model, heavy ion-nucleus scattering, nuclei with mass number 6 to 19, Nuclear Theory, 25.60.-t, 21.30.Fe, 24.10.-i, 25.60.Bx, nuclear forces, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

To study the effect of the weak binding energy on the interaction potential between a light exotic nucleus and a target, elastic scattering of 6He at 38.3 MeV/nucleon on a 12C target was measured at Grand Accélérateur National d'Ions Lourds (GANIL). The 6He beam was produced by fragmentation. The detection of the scattered particles was performed by the GANIL spectrometer. The energy resolution was good enough to separate elastic from inelastic scattering contributions. The measured elastic data have been analyzed within the optical model, with the real part of the optical potential calculated in the double-folding model using a realistic density-dependent nucleon-nucleon interaction and the imaginary part taken in the conventional Woods-Saxon (WS) form. A failure of the "bare" real folded potential to reproduce the measured angular distribution over the whole angular range suggests quite a strong coupling of the higher-order breakup channels to the elastic channel. To estimate the strength of the breakup effects, a complex surface potential with a repulsive real part (designed to simulate the polarization effects caused by the projectile breakup) was added to the real folded and imaginary WS potentials. A realistic estimate of the polarization potential caused by the breakup of the weakly bound 6He was made based on a parallel study of 6He+12C and 6Li+12C optical potentials at about the same energies.

Published
2002
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results