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Xu, S. S., Cui, Z. F., Chang, L., Papavassiliou, J., Roberts, C. D., & Zong, H. S. (2019). New perspective on hybrid mesons. Eur. Phys. J. A, 55(7), 113–6pp.
Abstract: We introduce a novel approach to the hybrid-meson (valence-gluon+quark+antiquark) bound-state problem in relativistic quantum field theory. Exploiting the existence of strong two-body correlations in the gluon-quark, q(g) = [gq], and gluon-antiquark, (q) over bar (g) = [g (q) over bar] channels, we argue that a sound description of hybrids can be obtained by solving a coupled pair of effectively two-body equations; and, consequently, that hybrids may be viewed as highly correlated q(g)(q) over bar <-> q (q) over bar (g) bound states. Analogies may be drawn between this picture of hybrid structure and that of baryons, in which diquark (quark+quark) correlations play a key role. The potential of this formulation is illustrated by calculating the spectrum of light-quark isovector hybrid mesons.
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Xie, J. J., & Oset, E. (2015). Photoproduction of the f(2)(1270) resonance. Eur. Phys. J. A, 51(9), 111–7pp.
Abstract: We have performed a calculation of the gamma(p) -> pi(+) p-p reaction, where the two pions have been separated in D-wave producing the f(2)(1270) resonance. We use elements of the local hidden gauge approach that provides the interaction of vector mesons in which the f(2)(1270) resonance appears as rho-rho. molecular state in L = 0 and spin 2. The vector meson dominance, incorporated in the local hidden gauge approach converts a photon into a rho(0) meson and the other meson connects the photon with the proton. The picture is simple and has no free parameters, since the parameters of the theory have been constrained in the previous study of the vector-vector states. In a second step we introduce new elements, not present in the local hidden gauge approach, adapting the rho propagator to Regge phenomenology and introducing the rho NN tensor coupling. We find that both the differential cross section as well as the t dependence of the cross section are in good agreement with the experimental results and provide support for the molecular picture of the f(2)(1270) resonance in the first baryonic reaction where it has been tested.
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Kucuk, L. et al, Orrigo, S. E. A., Montaner-Piza, A., Rubio, B., Gelletly, W., Algora, A., et al. (2017). Half-life determination of T-z =-1 and T-z =-1/2 proton-rich nuclei and the beta decay of Zn-58. Eur. Phys. J. A, 53(6), 134–10pp.
Abstract: We have measured the beta-decay half-lives of 16 neutron-deficient nuclei with T-z = -1/2 and -1, ranging from chromium to germanium. They were produced in an experiment carried out at GANIL and optimized for the production of Zn-58, for which in addition we present the decay scheme and absolute Fermi and Gamow-Teller transition strengths. Since all of these nuclei lie on the rp-process pathway, the T-1/2 values are important ingredients for the rp-process reaction flow calculations and for models of X-ray bursters.
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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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Mach, H., Lindroth, A., Ruchowska, E., Kvasil, J., Fogelberg, B., Gulda, K., et al. (2016). On the enhanced E1 transitions in the K=3/2 parity doublet band in Ra-223. Eur. Phys. J. A, 52(6), 172–10pp.
Abstract: We have applied the fast timing beta gamma gamma(t) technique to remeasure lifetimes of selected states in Ra-223 populated in the beta(-) decay of Fr-223. T-1/2 = 587(12) ps and 210(13) ps have been obtained for the 3/2(-) and 5/2(-) states at 50.1 and 79.7 keV, that are more accurate than the previous values of 630(70) ps and 166(55) ps, respectively. Our vertical bar D0 vertical bar value of 0.155(10) e.fm obtained for the K = 3/2 configuration together with the available values of vertical bar D0 vertical bar for the K = 1/2 and K = 5/2 parity doublet bands establish the configuration dependence of vertical bar D0 vertical bar at low spins in this nucleus. Results of theoretical calculations performed for Ra-223, using the quasiparticle-phonon model (QPM) with inclusion of the Coriolis coupling, reasonably well reproduce octupole correlations in this nucleus.
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