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Jungclaus, A. et al, Gadea, A., & Montaner-Piza, A. (2016). beta decay of semi-magic Cd-130: Revision and extension of the level scheme of In-130. Phys. Rev. C, 94(2), 024303–8pp.
Abstract: The beta decay of the semi-magic nucleus Cd-130 has been studied at the RIBF facility at the RIKEN Nishina Center. The high statistics of the present experiment allowed for a revision of the established level scheme of In-130 and the observation of additional beta feeding to high- lying core-excited states in In-130. The experimental results are compared to shell-model calculations employing a model space consisting of the full major N = 50-82 neutron and Z = 28-50 proton shells and the NA-14 interaction, and good agreement is found.
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Darai, J., Cseh, J., Antonenko, N. V., Royer, G., Algora, A., Hess, P. O., et al. (2011). Clusterization in the shape isomers of the (56)Ni nucleus. Physical Review C, 84(2), 024302.
Abstract: The interrelation of the quadrupole deformation and clusterization is investigated in the example of the (56)Ni nucleus. The shape isomers, including superdeformed and hyperdeformed states, are obtained as stability regions of the quasidynamical U(3) symmetry based on a Nilsson calculation. Their possible binary clusterizations are investigated by considering both the consequences of the Pauli exclusion principle and the energetic preference.
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Jin, S. Y. et al, & Algora, A. (2021). Spectroscopy of Cd-98 by two-nucleon removal from In-100. Phys. Rev. C, 104(2), 024302–6pp.
Abstract: Low-lying states of Cd-98 have been populated by the two-nucleon removal reaction (In-100, Cd-98+gamma) and studied using in-beam gamma-ray spectroscopy at the Radioactive Isotope Beam Factory at RIKEN. Two new gamma transitions were identified and assigned as decays from a previously unknown state. This state is suggested to be based on a pi 1g(/9/2)(-1)2p(1/2)(-2) configuration with J(pi) = 5(-). The present observation extends the systematics of the excitation energies of the first 5(-) state in N = 50 isotones toward Sn-100. The determined energy of the 5(- )state in Cd-98 continues a smooth trend along the N = 50 isotones. The systematics are compared with shell-model calculations in different model spaces. Good agreement is achieved when considering a model space consisting of the pi(1f(5/2), 2p(3/2), 2p(1/2), 1g(9/2)) orbitals. The calculations with a smaller model space omitting the orbitals below the Z = 38 subshell could not reproduce the experimental energy difference between the ground and first 5(-) states in N = 50 isotones, because proton excitations across Z = 38 subshell yield a large amount of correlation energy that lowers the ground states.
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Soderstrom, P. A. et al, & Montaner-Piza, A. (2013). Shape evolution in Ru-116,Ru-118: Triaxiality and transition between the O(6) and U(5) dynamical symmetries. Phys. Rev. C, 88(2), 024301–10pp.
Abstract: Ru-116 and Ru-118 have been studied via beta-delayed gamma-ray spectroscopy of nuclei produced in fragmentation reactions at the Radioactive Ion-Beam Factory (RIBF) facility. Level schemes with positive-parity states up to spin J = 6 have been constructed. The results have been discussed in terms of the interacting boson model, the algebraic collective model, and total Routhian surfaces. We conclude that the very neutron-rich nuclei still show many features associated with triaxial gamma-soft nuclei, represented by the O(6) symmetry, but are approaching a spherical structure, the U(5) symmetry, with increasing neutron number towards the N = 82 shell closure. In Ru-118, hints of a shape transition in the ground state have been observed.
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Pavon Valderrama, M. (2011). Perturbative renormalizability of chiral two-pion exchange in nucleon-nucleon scattering. Phys. Rev. C, 83(2), 024003–11pp.
Abstract: We study the perturbative renormalizability of chiral two-pion exchange for singlet and triplet channels within effective field theory, provided that the one-pion exchange piece of the interaction has been fully iterated. We determine the number of counterterms/subtractions needed to obtain finite results when the cutoff is removed, resulting in three counterterms for the singlet channel and six for the triplet. The results show that perturbative chiral two-pion exchange reproduce the data up to a center-of-mass momentum of k similar to 200-300 MeV in the singlet channel and k similar to 300-400 MeV in the triplet.
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Calle Cordon, A., Pavon Valderrama, M., & Ruiz Arriola, E. (2012). Charge independence, charge symmetry breaking in the S-wave nucleon-nucleon interaction, and renormalization. Phys. Rev. C, 85(2), 024002–13pp.
Abstract: We explore the interplay between renormalization, charge independence and charge symmetry breaking (CIB and CSB) in S-wave nucleon-nucleon scattering. The renormalizability requirement generates universality functions, that is, correlations between the low-energy scattering observables in the neutron-neutron, neutron-proton, and proton-proton systems. The universality functions only depend on the (known) form of the nucleon-nucleon potential at long distances and, in particular, they do not require any assumptions about short-range CIB and CSB effects. In addition, the inclusion of Coulomb effects is trivial for the particular case of proton-proton scattering, allowing us to relate strong and Coulomb scattering observables. Within this approach, and using a one-boson-exchange potential, the previous correlations are shown to be phenomenologically satisfied without the need to introduce further parameters.
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Garcilazo, H., Valcarce, A., & Vijande, J. (2016). Maximal isospin few-body systems of nucleons and Xi hyperons. Phys. Rev. C, 94(2), 024002–3pp.
Abstract: By using local central Yukawa-type interactions that reproduce the low-energy parameters of the latest updates of the Nijmegen ESC08c potentials, we show that the N Xi, NN Xi, N Xi Xi, and NN Xi Xi systems with maximal isospin are bound. Since in these states the strong decay N Xi -> Lambda Lambda is forbidden by isospin conservation, these strange few-body systems will be stable under the strong interaction. These results may suggest that other states with different number of Ns and Xi s in the maximal isospin channel could also be bound.
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n_TOF Collaboration(Lederer-Woods, C. et al.), Domingo-Pardo, C., & Tain, J. L. (2021). Destruction of the cosmic gamma-ray emitter Al-26 in massive stars: Study of the key Al-26(n, p) reaction. Phys. Rev. C, 104(2), L022803–7pp.
Abstract: The Al-26(n, p) Mg-26 reaction is the key reaction impacting on the abundances of the cosmic gamma-ray emitter Al-26 produced in massive stars and impacts on the potential pollution of the early solar system with Al-26 by asymptotic giant branch stars. We performed a measurement of the Al-26(n, p) Mg-26 cross section at the high-flux beam line EAR-2 at the n_TOF facility (CERN). We report resonance strengths for eleven resonances, nine being measured for the first time, while there is only one previous measurement for the other two. Our resonance strengths are significantly lower than the only previous values available. Our cross-section data range to 150 keV neutron energy, which is sufficient for a reliable determination of astrophysical reactivities up to 0.5 GK stellar temperature.
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HADES Collaboration(Agakishiev, G. et al), Diaz, J., & Gil, A. (2010). Lambda-p femtoscopy in collisions of Ar + KCl at 1.76AGeV. Phys. Rev. C, 82(2), 021901–5pp.
Abstract: Results on Lambda p femtoscopy are reported at the lowest energy so far. At a beam energy of 1.76AGeV, the reaction Ar + KCl was studied with the High Acceptance Di-Electron Spectrometer ( HADES) at SIS18/GSI. A high-statistics and high-purity Lambda sample was collected, allowing for the investigation of Lambda p correlations at low relative momenta. The experimental correlation function is compared to corresponding model calculations allowing the determination of the space-time extent of the Lambda p emission source. The Lambda p source radius is found to be slightly smaller than the pp correlation radius for a similar collision system. The present Lambda p radius is significantly smaller than that found for Au + Au/Pb + Pb collisions in the AGS, SPS, and RHIC energy domains but larger than that observed for electroproduction from He. Taking into account all available data, we find the Lambda p source radius to increase almost linearly with the number of participants to the power of one-third.
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n_TOF Collaboration(Zugec, P. et al), Domingo-Pardo, C., Giubrone, G., & Tain, J. L. (2014). Measurement of the C-12(n, p)B-12 cross section at n_TOF at CERN by in-beam activation analysis. Phys. Rev. C, 90(2), 021601–5pp.
Abstract: The integral cross section of the C-12(n, p)B-12 reaction has been determined for the first time in the neutron energy range from threshold to several GeV at the n_TOF facility at CERN. The measurement relies on the activation technique with the beta decay of B-12 measured over a period of four half-lives within the same neutron bunch in which the reaction occurs. The results indicate that model predictions, used in a variety of applications, are mostly inadequate. The value of the integral cross section reported here can be used as a benchmark for verifying or tuning model calculations.
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