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Bernardoni, F., Blossier, B., Bulava, J., Della Morte, M., Fritzsch, P., Garron, N., et al. (2015). B-meson spectroscopy in HQET at order 1/m. Phys. Rev. D, 92(5), 054509–25pp.
Abstract: We present a study of the B spectrum performed in the framework of heavy quark effective theory expanded to next-to-leading order in 1/m(b) and nonperturbative in the strong coupling. Our analyses have been performed on N-f = 2 lattice gauge field ensembles corresponding to three different lattice spacings and a wide range of pion masses. We obtain the B-s-meson mass and hyperfine splittings of the B-and B-s-mesons that are in good agreement with the experimental values and examine the mass difference m(Bs) – m(B) as a further cross-check of our previous estimate of the b-quark mass. We also report on the mass splitting between the first excited state and the ground state in the B and B-s systems.
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Binosi, D., Chang, L., Papavassiliou, J., & Roberts, C. D. (2015). Bridging a gap between continuum-QCD and ab initio predictions of hadron observables. Phys. Lett. B, 742, 183–188.
Abstract: Within contemporary hadron physics there are two common methods for determining the momentum-dependence of the interaction between quarks: the top-down approach, which works toward an ab initio computation of the interaction via direct analysis of the gauge-sector gap equations; and the bottom-up scheme, which aims to infer the interaction by fitting data within a well-defined truncation of those equations in the matter sector that are relevant to bound-state properties. We unite these two approaches by demonstrating that the renormalisation-group-invariant running-interaction predicted by contemporary analyses of QCD's gauge sector coincides with that required in order to describe ground-state hadron observables using a nonperturbative truncation of QCD's Dyson-Schwinger equations in the matter sector. This bridges a gap that had lain between nonperturbative continuum-QCD and the ab initioprediction of bound-state properties.
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Birkenbach, B. et al, & Gadea, A. (2015). Spectroscopy of the neutron-rich actinide nucleus U-240 following multinucleon-transfer reactions. Phys. Rev. C, 92(4), 044319–9pp.
Abstract: Background: Nuclear structure information for the neutron-rich actinide nuclei is important since it is the benchmark for theoretical models that provide predictions for the heaviest nuclei. Purpose: gamma-ray spectroscopy of neutron-rich heavy nuclei in the actinide region. Method: Multinucleon-transfer reactions in Zn-70 + U-238 and Xe-136 + U-238 have been measured in two experiments performed at the INFN Legnaro, Italy. In the Zn-70 experiment the high-resolution HPGe Clover Array (CLARA) coupled to the magnetic spectrometer PRISMA was employed. In the Xe-136 experiment the high-resolution Advanced Gamma Tracking Array (AGATA) was used in combination with PRISMA and the Detector Array for Multinucleon Transfer Ejectiles (DANTE). Results: The ground-state band (g.s. band) of U-240 was measured up to the 20(+) level and a tentative assignment was made up to the (24(+)) level. Results from gamma gamma coincidence and from particle coincidence analyses are shown. Moments of inertia (MoI) show a clear upbend. Evidence for an extended first negative-parity band of U-240 is found. Conclusions: A detailed comparison with latest calculations shows best agreement with cranked relativistic Hartree-Bogoliubov (CRHB) calculations for the g.s. band properties. The negative-parity band shows the characteristics of a K-pi = 0 band based on an octupole vibration.
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Biswas, A., Sinha, N., & Abbas, G. (2015). Nonleptonic decays of charmed mesons into two pseudoscalars. Phys. Rev. D, 92(1), 014032–16pp.
Abstract: We examine the role of resonant coupled channel final state interactions (FSIs), as well as weak annihilation and exchange contributions, in explaining all the two-body hadronic D -> PP decay modes. In the un-unitarized amplitudes we include modified Wilson coefficients with nonfactorizable corrections as parameters. For the hadronic form factors, the z-series expansion method is used to get the q(2) dependence. The FSI effects are incorporated via a phenomenological approach with widths of resonances to various channels taken from observations where available, and others as additional parameters to be determined from fits of all the theoretical rates to the measured ones. Our results for the rather hard to explain D-0 -> K+K-, pi(+)pi(-) are in agreement with measured values. We demonstrate that both weak exchange and FSI effects are required to get the correct branching ratio for the D-0 -> K-0(K) over bar (0) mode. Using our unitarized amplitudes we evaluate the strong phase difference between the amplitudes for D-0 -> K-pi(+) and D-0 -> K+pi(-) and find it to be in complete agreement with the recent BES III result.
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Bizzeti, P. G., Sona, P., Michelagnoli, C., Melon, B., Bazzacco, D., Farnea, E., et al. (2015). Analyzing power of AGATA triple clusters for gamma-ray linear polarization. Eur. Phys. J. A, 51(4), 49–11pp.
Abstract: We have investigated the ability of AGATA triple clusters to measure the linear polarization of gamma rays, exploiting the azimuthal-angle dependence of the Compton scattering differential cross section. To this aim, partially polarized gamma rays have been produced by Coulomb excitation of the first excited state of Pd-104 and Pd-108, which decay to the ground state by emission of gamma rays of 555.8 keV and 433.9 keV, respectively. Pulse-shape analysis and gamma-ray tracking techniques have been used to determine the position and time sequence of the interaction points inside the germanium crystals. Anisotropies in the detection efficiency have been taken into account using 661.6 keV gammas from a Cs-137 radioactive source. We obtain an average analyzing power of 0.451(34) at 433.9 keV and 0.484(24) at 555.8 keV.
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