Pavon Valderrama, M., & Ruiz Arriola, E. (2011). Renormalization of chiral two-pion exchange NN interactions with Delta excitations: Correlations in the partial-wave expansion. Phys. Rev. C, 83(4), 044002–19pp.
Abstract: In this work we consider the renormalization of the chiral two-pion exchange potential with explicit Delta excitations for nucleon-nucleon scattering at next-to-leading (NLO) and next-to-next-to-leading order (N(2)LO). Because of the singular nature of the chiral potentials, correlations between different partial waves are generated. In particular, we show that two-body scattering by a short distance power like singular attractive interaction can be renormalized in all partial waves with a single counterterm, provided the singularities are identical. A parallel statement holds in the presence of tensor interactions when the eigenpotentials in the coupled channel problem also coincide. Although this construction reduces the total number of counterterms to 11 in the case of nucleon-nucleon scattering with chiral two-pion exchange interactions with Delta degrees of freedom, the differences in the scattering phases as compared to the case with the uncorrelated partial-wave renormalization become smaller as the angular momentum is increased in the elastic scattering region.
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Ikeno, N., Yamagata-Sekihara, J., Nagahiro, H., Jido, D., & Hirenzaki, S. (2011). Formation of heavy-meson bound states by two-nucleon pick-up reactions. Phys. Rev. C, 84(5), 054609–7pp.
Abstract: We develop a model to evaluate the formation rate of the heavy mesic nuclei in two-nucleon pick-up reactions and apply it to the (6)Li target cases for the formation of heavy meson-alpha bound states, as examples. The existence of the quasideuteron in the target nucleus is assumed in this model. It is found that mesic nuclei formation in recoilless kinematics is possible even for heavier mesons than the nucleon in two-nucleon pick-up reactions. We find the formation rate of the meson-alpha bound states can be around half of the elementary cross sections at the recoilless kinematics with small distortions.
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Steer, S. J. et al, & Estevez, M. E. (2011). Isomeric states observed in heavy neutron-rich nuclei populated in the fragmentation of a (208)Pb beam. Phys. Rev. C, 84(4), 044313–22pp.
Abstract: Heavy neutron-rich nuclei were populated via the fragmentation of a E/A = 1 GeV (208)(82)Pb beam. Secondary fragments were separated and identified and subsequently implanted in a passive stopper. By the detection of delayed gamma rays, isomeric decays associated with these nuclei have been identified. A total of 49 isomers were detected, with the majority of them observed for the first time. The newly discovered isomers are in (204,205)(80)Hg, (201,202,204,205)(79)Au, (197,203,204)(78)Pt, (195,199-203)(77)Ir, (193,197-199)(76)Os, (196)(75)Re, (190,191)(74)W, and (189)(73)Ta. Possible level schemes are constructed and the structure of the nuclei discussed. To aid the interpretation, shell-model as well as BCS calculations were performed.
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Perez-Cerdan, A. B., Rubio, B., Gelletly, W., Algora, A., Agramunt, J., Burkard, K., et al. (2011). beta decay of (78)Sr. Phys. Rev. C, 84(5), 054311–15pp.
Abstract: The gamma rays and conversion electrons emitted in the beta decay of (78)Sr to levels in (78)Rb have been studied using Ge detectors and a mini-orange spectrometer. A reliable level scheme based on the results of these experiments has been established. The properties of the levels in (78)Rb have been compared with calculations based on deformed Hartree-Fock with Skyrme interactions and pairing correlations in the BCS approximation. This has allowed an interpretation of the nature of the observed sets of levels in the odd-odd nucleus (78)Rb.
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Haider, H., Ruiz Simo, I., Sajjad Athar, M., & Vicente Vacas, M. J. (2011). Nuclear medium effects in nu(nu)-nucleus deep inelastic scattering. Phys. Rev. C, 84(5), 054610–13pp.
Abstract: We study nuclear medium effects in the weak structure functions F(2)(x, Q(2)) and F(3)(x, Q(2)) in the deep inelastic neutrino and antineutrino induced reactions in nuclei. We use a theoretical model for the nuclear spectral functions which incorporates the conventional nuclear effects, such as Fermi motion, binding, and nucleon correlations. We also consider the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. The calculations have been performed using relativistic nuclear spectral functions. Our results are compared with the experimental data of the NuTeV and the CERN Dortmund Heidelberg Saclay Warsaw (CDHSW) collaborations.
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Puppe, P., Frekers, D., Adachi, T., Akimune, H., Aoi, N., Bilgier, B., et al. (2011). High-resolution ((3)He,t) reaction on the double-beta decaying nucleus (136)Xe. Phys. Rev. C, 84(5), 051305–5pp.
Abstract: A ((3)He, t) charge-exchange reaction experiment on the double-beta decaying nucleus (136)Xe has been performed at an incident energy of 420 MeV with the objective to measure the Gamow-Teller (GT) strength distribution in (136)Cs. The measurements have been carried out at the dispersion-matched WS beam line and the Grand Raiden spectrometer of the Research Center for Nuclear Physics in Osaka, where an energy resolution of 42 keV was achieved. A new gas cell with thin windows made of polyethylene naphthalate has been employed as a target. The extracted GT strength distribution is confronted with the rather long 2 nu beta beta decay half-life of (136)Xe.
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n_TOF Collaboration(Tagliente, G. et al.), Domingo-Pardo, C., & Tain, J. L. (2011). (96)Zr(n,gamma) measurement at the n_TOF facility at CERN. Phys. Rev. C, 84(5), 055802–8pp.
Abstract: The (n,gamma) cross section of (96)Zr has been investigated at the CERN n_TOF spallation neutron source. High-resolution time-of-flight measurements using an enriched ZrO(2) sample allowed us to analyze 15 resonances below 40 keV with improved accuracy. On average, the capture widths were found to be 25% smaller than reported in earlier experiments. If complemented with the contribution by direct radiative capture, the derived Maxwellian averaged cross sections are consistent with activation data at kT = 25 keV. The present results confirm the astrophysical implications for the s-process branching at (95)Zr.
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Montanari, D. et al, & Gadea, A. (2011). Elastic, inelastic, and one-nucleon transfer processes in (48)Ca+(64)Ni. Phys. Rev. C, 84(5), 9pp.
Abstract: Elastic, inelastic, and one-nucleon transfer channels in the (48)Ca+(64)Ni reaction have been measured at approximate to 6 MeV/nucleon with the PRISMA-CLARA setup, at Legnaro National Laboratory, consisting of the coupling of a large solid angle magnetic spectrometer with a germanium array. By trajectory reconstruction the reaction products have been fully identified in mass, nuclear charge, and kinetic energy, while coincident gamma spectra of binary partners have been constructed after Doppler correction. Absolute differential cross sections have been extracted for the inelastic excitation and one-nucleon transfer, also for specific excited states. The data are in good agreement with semiclassical calculations and distorted wave Born approximation predictions. The work outlines an experimental method which can become valuable to extract structural information from heavy-ion reaction studies.
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n_TOF Collaboration(Sarmento, R. et al), Domingo-Pardo, C., & Tain, J. L. (2011). Measurement of the (236)U(n, f) cross section from 170 meV to 2 MeV at the CERN n_TOF facility. Phys. Rev. C, 84(4), 044618–10pp.
Abstract: The neutron-induced fission cross section of (236)U was measured at the neutron Time-of-Flight (nTOF) facility at CERN relative to the standard (235)U(n, f) cross section for neutron energies ranging from above thermal to several MeV. The measurement, covering the full range simultaneously, was performed with a fast ionization chamber, taking advantage of the high resolution of the nTOF spectrometer. The n_TOF results confirm that the first resonance at 5.45 eV is largely overestimated in some nuclear data libraries. The resonance triplet around 1.2 keV was measured with high resolution and resonance parameters were determined with good accuracy. Resonances at high energy have also been observed and characterized and different values for the cross section are provided for the region between 10 keV and the fission threshold. The present work indicates various shortcomings of the current nuclear data libraries in the subthreshold region and provides the basis for an accurate re-evaluation of the (236)U(n, f) cross section, which is of great relevance for the development of emerging or innovative nuclear reactor technologies.
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Krolas, W. et al, & Gadea, A. (2011). Coupling of the proton-hole and neutron-particle states in the neutron-rich (48)K isotope. Phys. Rev. C, 84(6), 064301–8pp.
Abstract: Excited states in the Z = 19, N = 29 neutron-rich (48)K isotope have been studied using deep-inelastic transfer reactions with a thick target at Gammasphere and with a thin target at the PRISMA-CLARA spectrometer. The lowest excited states were located; they involve a proton hole in the s(1/2) or d(3/2) orbital coupled to a p(3/2) neutron. A new 7.1(5)-ns, 5(+) isomer, the analog of the 7/2 isomer in (47)K, was identified. Based on the observed gamma-decay pattern of the isomer a revised spin-parity assignment of 1(-) is proposed for the ground state of (48)K.
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