Batist, L., Gorska, M., Grawe, H., Janas, Z., Kavatsyuk, M., Karny, M., et al. (2010). Systematics of Gamow-Teller beta decay “Southeast” of Sn-100. Eur. Phys. J. A, 46(1), 45–53.
Abstract: The energy centroids and integrated strengths of Gamow-Teller transitions in the beta(+) and electron-capture decay are analyzed for nuclei whose proton number Z and neutron number N are restricted to 44 <= Z <= 50 and 50 <= N <= 58. The analysis is based on data measured both with high-resolution gamma-ray spectrometry and total gamma-ray absorption techniques. The dependence of the considered quantities on the relative neutron excess are established after taking into account the effects due to the Coulomb interaction and mean-field level occupancies. An extrapolation of this dependence to the lightest known tin isotopes is used to estimate the decay characteristics of Sn-100 and Sn-101. The values extrapolated for the half-lives of Sn-100 and Sn-101 agree with experimental data. Using the extrapolated values together with shell model predictions, the Q values for the electron-capture decay of Sn-100 is evaluated. The quenching factor for beta(+) and the electron-capture decay of the nuclei under consideration here is established to be 0.56(2) with a possible weak dependence on N – Z.
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Jido, D., Oset, E., & Sekihara, T. (2011). Kaon-induced Lambda(1405) production on a deuteron target at DAFNE. Eur. Phys. J. A, 47(3), 42–7pp.
Abstract: The K-- induced production of.(1405) in the K(-)d -> pi Sigma n reaction is investigated having in mind the conditions of the DAFNE facility at Frascati where kaons are obtained from the decay of slow-moving phi mesons. We find that the K(-)d -> Lambda(1405)n process favors the production of Lambda(1405) initiated by the K(-)p channel, which gives largest weight to the higher mass Lambda(1405) appearing at 1420MeV in chiral theories. We find that the fastest kaons from the decay of the phi are well suited to see this resonance, particularly if one selects forward going neutrons in the center of mass, which reduce the contribution of single scattering and make the double scattering dominate where the signal of the resonance appears clearer.
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Montanari, D., Farnea, E., Leoni, S., Pollarolo, G., Corradi, L., Benzoni, G., et al. (2011). Response function of the magnetic spectrometer PRISMA. Eur. Phys. J. A, 47(1), 4–7pp.
Abstract: The response function of the magnetic spectrometer PRISMA is studied via a Monte Carlo simulation that employs a ray tracing code to determine the trajectories of individual rays through the electromagnetic fields. The calculated response is tested on angular and energy distributions provided by theoretical calculations for the Ca-48 + Ni-64 multinucleon transfer reaction and applied to the corresponding experimental data.
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n_TOF Collaboration(Belloni, F. et al), Domingo-Pardo, C., & Tain, J. L. (2011). Neutron-induced fission cross-section of U-233 in the energy range 0.5 < E-n < 20 MeV. Eur. Phys. J. A, 47(1), 2–7pp.
Abstract: The neutron-induced fission cross-section of U-233 has been measured at the CERN nTOF facility relative to the standard fission cross-section of U-235 between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against alpha-particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the nTOF facility result in data with uncertainties of approximate to 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the U-233(n, f) cross-section and, consequently, the design of energy systems based on the Th/U cycle.
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HADES Collaboration(Agakishiev, G. et al), Diaz, J., & Gil, A. (2011). Hyperon production in Ar plus KCl collisions at 1.76A GeV. Eur. Phys. J. A, 47(2), 21–9pp.
Abstract: We present transverse momentum spectra, rapidity distribution and multiplicity of Lambda-hyperons measured with the HADES spectrometer in the reaction Ar(1.76A GeV) + KCl. The yield of Xi(-) is calculated from our previously reported Xi(-)/(Lambda+Sigma(0)) ratio and compared to other strange particle multiplicities. Employing a strangeness balance equation the multiplicities of the yet unmeasured Sigma(+/-)-hyperons can be estimated. Finally a statistical hadronization model is used to fit the yields of pi(-), K+, K-s(0), K-, phi, Lambda and Xi(-). The resulting chemical freeze-out temperature of T = (76 +/- 2) MeV is compared to the measured slope parameters obtained from fits to the transverse mass distributions of the different particles.
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Courtoy, A., Scopetta, S., & Vento, V. (2011). Non-perturbative momentum dependence of the coupling constant and hadronic models. Eur. Phys. J. A, 47(4), 49–7pp.
Abstract: Models of hadron structure are associated with a hadronic scale which allows by perturbative evolution to calculate observables in the deep inelastic region. The resolution of Dyson-Schwinger equations leads to the freezing of the QCD running coupling (effective charge) in the infrared, which is best understood as a dynamical generation of a gluon mass function, giving rise to a momentum dependence which is free from infrared divergences. We use this new development to understand why perturbative treatments are working reasonably well despite the smallness of the hadronic scale.
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HADES Collaboration(Agakishiev, G. et al), Diaz, J., & Gil, A. (2011). pp and pi pi intensity interferometry in collisions of Ar+KCl at 1.76A GeV. Eur. Phys. J. A, 47(5), 63–8pp.
Abstract: Results on pp, pi(+) pi(+), and pi-pi-intensity interferometry are reported for collisions of Ar+KCl at 1.76A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The experimental correlation functions as a function of the relative momentum are compared to model calculations allowing the determination of the space-time extent of the corresponding emission sources. The pp source radii are found significantly larger than the pp emission radius. The present radii do well complement the beam-energy dependences of Gaussian source radii of the collision system of size A + A similar or equal to 40 + 40. The pp source radius at fixed beam energy is found to increase linearly with the cube root of the number of participants. From this trend, a lower limit of the pp correlation radius is deduced.
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n_TOF Collaboration(Belloni, F. et al), Domingo-Pardo, C., & Tain, J. L. (2011). Measurement of the neutron-induced fission cross-section of Am-243 relative to U-235 from 0.5 to 20 MeV. Eur. Phys. J. A, 47(12), 160–8pp.
Abstract: The ratio of the neutron-induced fission cross-sections of Am-243 and U-235 was measured in the energy range from 0.5 to 20 MeV with uncertainties of approximate to 4%. The experiment was performed at the CERN n_TOF facility using a fast ionization chamber. With the good counting statistics that could be achieved thanks to the high instantaneous flux and the low backgrounds, the present results are useful for resolving discrepancies in previous data sets and are important for future reactors with improved fuel burn-up.
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Nishimura, D., Fujita, Y., Fukuda, M., Ganioglu, E., Ichikawa, Y., Kanazawa, M., et al. (2011). Beta and gamma decays of J(pi)=1(+), Al-24m state beta and gamma branching ratios. Eur. Phys. J. A, 47(12), 155–7pp.
Abstract: A beta-gamma spectroscopy of the J(pi) = 1(+), 426 keV isomeric state of Al-24 ( Al-24m) has been carried out by using a Al-24 secondary beam with high purity and high isomeric ratio. From the absolute gamma-ray and beta-particle intensities observed in the decay of the isomeric state, the branching ratio R-B of the isomeric gamma-decay from Al-24m to the J(pi) = 4(+), ground state of Al-24 have been derived. The obtained R-B value of 69.6(7)% is much smaller than the previously accepted value of 82.5(30)%. The precise half-life for the isomer decay, T-1/2(m) = 130.9(13) ms, has been also determined in this experiment. Accordingly, the M3 gamma-decay strength B(M3) of the Al-24m decay becomes smaller and the total beta-decay branching ratio becomes larger. In particular, the beta-decay branching ratio to the ground state of Mg-24 becomes 24.3(9)%, which is 2.4 times larger than the previous value of 10.1(28)%. By combining the branching ratio and the half-life, the Gamow-Teller (GT) transition strength B(GT) of 0.0194(7) is deduced for the GT transition from Al-24m to the J(pi) = 0(+), ground state of Mg-24. This value is in good agreement with the values derived from charge-exchange reactions.
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Garzon, E. J., & Oset, E. (2012). Effects of pseudoscalar-baryon channels in the dynamically generated vector-baryon resonances. Eur. Phys. J. A, 48(1), 5–20pp.
Abstract: We study the interaction of vector mesons with the octet of stable baryons in the framework of the local hidden gauge formalism using a coupled-channels unitary approach, including also the pseudoscalar-baryon channels which couple to the same quantum numbers. We examine the scattering amplitudes and their poles, which can be associated to the known J(P) = 1/2(-), 3/2(-) baryon resonances, and determine the role of the pseudoscalar-baryon channels, changing the width and eventually the mass of the resonances generated with only the basis of vector-baryon states.
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