|
|
Guadilla, V. et al, Algora, A., Tain, J. L., Agramunt, J., Jordan, M. D., Montaner-Piza, A., et al. (2017). Experimental study of Tc-100 beta decay with total absorption gamma-ray spectroscopy. Phys. Rev. C, 96(1), 014319–10pp.
Abstract: The beta decay of Tc-100 has been studied by using the total absorption gamma-ray spectroscopy technique at the Ion Guide Isotope Separator On-Line facility in Jyvaskyla. In this work the new Decay Total Absorption gamma-ray Spectrometer in coincidence with a cylindrical plastic beta detector has been employed. The beta intensity to the ground state obtained from the analysis is in good agreement with previous high-resolution measurements. However, differences in the feeding to the first-excited state as well as weak feeding to a new level at high excitation energy have been deduced from this experiment. Theoretical calculations performed in the quasiparticle random-phase approximation framework are also reported. Comparison of these calculations with our measurement serves as a benchmark for calculations of the double beta decay of Mo-100.
|
|
|
|
Rice, S. et al, Algora, A., Tain, J. L., Valencia, E., Agramunt, J., Rubio, B., et al. (2017). Total absorption spectroscopy study of the beta decay of Br-86 and Rb-91. Phys. Rev. C, 96(1), 014320–10pp.
Abstract: The beta decays of Br-86 and Rb-91 have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the Ion Guide Isotope Separator On-Line facility in Jyvaskyla and further purified using the JYFLTRAP. Br-86 and Rb-91 are considered to be major contributors to the decay heat in reactors. In addition, Rb-91 was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decaywas well known from high-resolution measurements. Our results show that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renormalized. The relative impact of the studied decays in the prediction of the decay heat and antineutrino spectrum from reactors has been evaluated.
|
|
|
|
Fernandez-Soler, P., & Ruiz Arriola, E. (2017). Coarse graining of NN inelastic interactions up to 3 GeV: Repulsive versus structural core. Phys. Rev. C, 96(1), 014004–14pp.
Abstract: The repulsive short-distance core is one of the main paradigms of nuclear physics which even seems confirmed by QCD lattice calculations. On the other hand nuclear potentials at short distances are motivated by high energy behavior where inelasticities play an important role. We analyze NN interactions up to 3 GeV in terms of simple coarse grained complex and energy dependent interactions. We discuss two possible and conflicting scenarios which share the common feature of a vanishing wave function at the core location in the particular case of S waves. We find that the optical potential with a repulsive core exhibits a strong energy dependence whereas the optical potential with the structural core is characterized by a rather adiabatic energy dependence which allows one to treat inelasticity perturbatively. We discuss the possible implications for nuclear structure calculations of both alternatives.
|
|
|
|
Pavao, R., Sakai, S., & Oset, E. (2018). Production of N*(1535) and N*(1650) in Lambda(c)-> (K)over-bar(0)eta p (pi N) decay. Phys. Rev. C, 98(1), 015201–8pp.
Abstract: To study the properties of the N*(1535) and N*(1650), we calculate the mass distributions of MB in the Lambda(c) -> (K) over bar (MB)-M-0 decay, with MB = pi N(I = 1/2), eta p, and K Sigma(I = 1/2). We do this by calculating the tree-level and loop contributions, mixing pseudoscalar-baryon and vector-baryon channels using the local hidden gauge formalism. The loop contributions for each channel are calculated using the chiral unitary approach. We observe that for the eta N mass distribution only the N* (1535) is seen, with the N* (1650) contributing to the width of the curve, but for the pi N mass distribution both resonances are clearly visible. In the case of MB = K Sigma, we found that the strength of the K E mass distribution is smaller than that of the mass distributions of the pi N and eta p in the Lambda(+)(c)-> (K) over bar (0)pi N and Lambda(+)(c) -> (K) over bar (0)eta p processes, in spite of this channel having a large coupling to the N* (1650). This is because the K Sigma pair production is suppressed in the primary production from the Lambda(c) decay.
|
|
|
|
AGATA Collaboration(Kaya, L. et al), & Gadea, A. (2018). High-spin structure in the transitional nucleus Xe-131: Competitive neutron and proton alignment in the vicinity of the N=82 shell closure. Phys. Rev. C, 98(1), 014309–19pp.
Abstract: The transitional nucleus Xe-131 is investigated after multinucleon transfer in the Xe-136 + Pb-208 and Xe-136 +U-238 reactions employing the high-resolution Advanced gamma-Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and as an elusive reaction product in the fusion-evaporation reaction Sn-124(B-11) ,p3n)Xe-131 employing the High-efficiency Observatory for gamma-Ray Unique Spectroscopy (HORUS) gamma-ray array coupled to a double-sided silicon strip detector at the University of Cologne, Germany. The level scheme of Xe-131 is extended to 5 MeV. A pronounced backbending is observed at (h) over bar omega approximate to 0.4 MeV along the negative-parity one-quasiparticle vh(11/12)(alpha = -1/2) band. The results are compared to the high-spin systematics of the Z = 54 isotopes and the N = 77 isotones. Large-scale shell-model calculations employing the PQM130, SN100PN, GCN50:82, SN100-KTH, and a realistic effective interaction reproduce the experimental findings and provide guidance to elucidate the structure of the high-spin states. Further calculations in Xe129-132 provide insight into the changing nuclear structure along the Xe chain towards the N = 82 shell closure. Proton occupancy in the pi 0h(11/2) orbital is found to be decisive for the description of the observed backbending phenomenon.
|
|
