Hadronic interactions of primary cosmic rays with the FLUKA code

The measured fluxes of secondary particles produced by the interactions of cosmic rays with the astronomical environment represent a powerful tool to infer some properties of primary cosmic rays. In this work we investigate the production of secondary particles in inelastic hadronic interactions between several cosmic rays species of projectiles and different target nuclei of the interstellar medium. The yields of secondary particles have been calculated with the FLUKA simulation package, that provides with very good accuracy the energy distributions of secondary products in a large energy range. An application to the propagation and production of secondaries in the Galaxy is presented.Comment: 8 pages, 4 figures; Contribution to the 34th International Cosmic Ray Conference, July 30 to August 6, The Hague, Netherlands; fixing a typo in the y-axis label of Fig.

Bimagnon studies in cuprates with Resonant Inelastic X-ray Scattering at the O K edge. II - The doping effect in La2-xSrxCuO4

We present RIXS data at O K edge from La2-xSrxCuO4 vs. doping between x=0.10 and x=0.22 with attention to the magnetic excitations in the Mid-Infrared region. The sampling done by RIXS is the same as in the undoped cuprates provided the excitation is at the first pre-peak induced by doping. Note that this excitation energy is about 1.5 eV lower than that needed to see bimagnons in the parent compound. This approach allows the study of the upper region of the bimagnon continuum around 450 meV within about one third of the Brilluoin Zone around \Gamma. The results show the presence of damped bimagnons and of higher even order spin excitations with almost constant spectral weight at all the dopings explored here. The implications on high Tc studies are briefly addressed

Coherent molecule formation in anharmonic potentials near confinement-induced resonances

We perform a theoretical and experimental study of a system of two ultracold atoms with tunable interaction in an elongated trapping potential. We show that the coupling of center-of-mass and relative motion due to an anharmonicity of the trapping potential leads to a coherent coupling of a state of an unbound atom pair and a molecule with a center of mass excitation. By performing the experiment with exactly two particles we exclude three-body losses and can therefore directly observe coherent molecule formation. We find quantitative agreement between our theory of inelastic confinement-induced resonances and the experimental results. This shows that the effects of center-of-mass to relative motion coupling can have a significant impact on the physics of quasi-1D quantum systems.Comment: 7 pages, 4 figure

Temperature dependence of iron local magnetic moment in phase-separated superconducting chalcogenide

We have studied local magnetic moment and electronic phase separation in superconducting K$_{x}$Fe$_{2-y}$Se$_2$ by x-ray emission and absorption spectroscopy. Detailed temperature dependent measurements at the Fe K-edge have revealed coexisting electronic phases and their correlation with the transport properties. By cooling down, the local magnetic moment of Fe shows a sharp drop across the superconducting transition temperature (T$_c$) and the coexisting phases exchange spectral weights with the low spin state gaining intensity at the expense of the higher spin state. After annealing the sample across the iron-vacancy order temperature, the system does not recover the initial state and the spectral weight anomaly at T$_c$ as well as superconductivity disappear. The results clearly underline that the coexistence of the low spin and high spin phases and the transitions between them provide unusual magnetic fluctuations and have a fundamental role in the superconducting mechanism of electronically inhomogeneous K$_{x}$Fe$_{2-y}$Se$_2$ system.Comment: 6 pages, 5 figure

Space-time properties of free motion time-of-arrival eigenstates

The properties of the time-of-arrival operator for free motion introduced by Aharonov and Bohm and of its self-adjoint variants are studied. The domains of applicability of the different approaches are clarified. It is shown that the arrival time of the eigenstates is not sharply defined. However, strongly peaked real-space (normalized) wave packets constructed with narrow Gaussian envelopes centred on one of the eigenstates provide an arbitrarily sharp arrival time.Comment: REVTEX, 12 pages, 4 postscript figure

The worldwide costs of marine protected areas

Declines in marine harvests, wildlife, and habitats have prompted calls at both the 2002 World Summit on Sustainable Development and the 2003 World Parks Congress for the establishment of a global system of marine protected areas (MPAs). MPAs that restrict fishing and other human activities conserve habitats and populations and, by exporting biomass, may sustain or increase yields of nearby fisheries. Here we provide an estimate of the costs of a global MPA network, based on a survey of the running costs of 83 MPAs worldwide. Annual running costs per unit area spanned six orders of magnitude, and were higher in MPAs that were smaller, closer to coasts, and in high-cost, developed countries. Models extrapolating these findings suggest that a global MPA network meeting the World Parks Congress target of conserving 20–30% of the world’s seas might cost between $5 billion and$19 billion annually to run and would probably create around one million jobs. Although substantial, gross network costs are less than current government expenditures on harmful subsidies to industrial fisheries. They also ignore potential private gains from improved fisheries and tourism and are dwarfed by likely social gains from increasing the sustainability of fisheries and securing vital ecosystem services