|
|
Barenboim, G., & Oteo, J. A. (2013). One pendulum to run them all. Eur. J. Phys., 34(4), 1049–1065.
Abstract: The analytical solution for the three-dimensional linear pendulum in a rotating frame of reference is obtained, including Coriolis and centrifugal accelerations, and expressed in terms of initial conditions. This result offers the possibility of treating Foucault and Bravais pendula as trajectories of the same system of equations, each of them with particular initial conditions. We compare them with the common two-dimensional approximations in textbooks. A previously unnoticed pattern in the three-dimensional Foucault pendulum attractor is presented.
|
|
|
|
n_TOF Collaboration(Guerrero, C. et al), Domingo-Pardo, C., Giubrone, G., & Tain, J. L. (2013). Performance of the neutron time-of-flight facility n_TOF at CERN. Eur. Phys. J. A, 49(2), 27–15pp.
Abstract: The neutron time-of-flight facility n_TOF features a white neutron source produced by spallation through 20 GeV/c protons impinging on a lead target. The facility, aiming primarily at the measurement of neutron-induced reaction cross sections, was operating at CERN between 2001 and 2004, and then underwent a major upgrade in 2008. This paper presents in detail all the characteristics of the new neutron beam in the currently available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The characteristics discussed include the intensity and energy dependence of the neutron flux, the spatial profile of the beam, the in-beam background components and the energy resolution/broadening. The discussion of these features is based on dedicated measurements and Monte Carlo simulations, and includes estimations of the systematic uncertainties of the mentioned quantities.
|
|
|
|
Xiao, C. W., Aceti, F., & Bayar, M. (2013). The small K pi component in the K* wave functions. Eur. Phys. J. A, 49(2), 22–5pp.
Abstract: We use a recently developed formalism which generalizes Weinberg's compositeness condition to partial waves higher than s-wave in order to determine the probability of having a K pi component in the K* wave function. A fit is made to the K pi phase shifts in p-wave, from where the coupling of K* to K pi and the K pi loop function are determined. These ingredients allow us to determine that the K* is a genuine state, different from a K pi component, in a proportion of about 80%.
|
|
|
|
n_TOF Collaboration(Belloni, F. et al), Domingo-Pardo, C., & Tain, J. L. (2013). Measurement of the neutron-induced fission cross-section of Am-241 at the time-of-flight facility n_TOF. Eur. Phys. J. A, 49(1), 2–6pp.
Abstract: The neutron-induced fission cross-section of Am-241 has been measured relative to the standard fission cross-section of U-235 between 0.5 and 20 MeV. The experiment was performed at the CERN nTOF facility. Fission fragments were detected by a fast ionization chamber by discriminating against the alpha-particles from the high radioactivity of the samples. The high instantaneous neutron flux and the low background of the nTOF facility enabled us to obtain uncertainties of approximate to 5%. With the present results it was possible to resolve discrepancies between previous data sets and to confirm current evaluations, thus providing important information for design studies of future reactors with improved fuel burn-up.
|
|
|
|
HADES Collaboration(Agakishiev, G. et al), Diaz, J., & Gil, A. (2013). Deep sub-threshold K*(892)(0) production in collisions of Ar + KCl at 1.76A GeV. Eur. Phys. J. A, 49(3), 34–7pp.
Abstract: Results on the deep sub-threshold production of the short-lived hadronic resonance K*(892)(0) are reported for collisions of Ar + KCl at 1.76 A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The K*(892)(0) production probability per central collision of P-K*0 = (4.4 +/- 1.1 +/- 0.5) x 10(-4) and the K*(892)(0)/K-0 ratio of P-K*0/P-K0 = (1.9 +/- 0.5 +/- 0.3) x 10(-2) are determined at the lowest energy so far (i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, root s(NN)-root s(thr) = -340MeV). The K*(0)/K-0 ratio is compared with results of other experiments and with the predictions of the UrQMD transport approach and of the statistical hadronization model. The experimental K*(0) yield and the K-*0/K-0 ratio are overestimated by the transport model by factors of about five and two, respectively. In a chemically equilibrated medium the ratio corresponds to a temperature of the thermalized system being systematically lower than the value determined by the yields of the stable and long-lived hadrons produced in Ar + KCl collisions. From the present measurement, we conclude that sub-threshold K* production either cannot be considered to proceed in a system being in thermal equilibrium or these short-lived resonances appear undersaturated, for example as a result of the rescattering of the decay particles in the ambient hadronic medium.
|
|
