Stimulated Neutrino Transformation with Sinusoidal Density Profiles

Large amplitude oscillations between the states of a quantum system can be stimulated by sinusoidal external potentials with frequencies that are similar to the energy level splitting of the states or a fraction thereof. Situations when the applied frequency is equal to an integer fraction of the energy level splittings are known as parametric resonances. We investigate this effect for neutrinos both analytically and numerically for the case of arbitrary numbers of neutrino flavors. We look for environments where the effect may be observed and find that supernova are the one realistic possibility due to the necessity of both large densities and large amplitude fluctuations. The comparison of numerical and analytic results of neutrino propagation through a model supernova reveals it is possible to predict the locations and strengths of the stimulated transitions that occur.Comment: 14 pages, 6 figure

Neutrinos And Big Bang Nucleosynthesis

The early universe provides a unique laboratory for probing the frontiers of particle physics in general and neutrino physics in particular. The primordial abundances of the relic nuclei produced during the first few minutes of the evolution of the Universe depend on the electron neutrinos through the charged-current weak interactions among neutrons and protons (and electrons and positrons and neutrinos), and on all flavors of neutrinos through their contributions to the total energy density which regulates the universal expansion rate. The latter contribution also plays a role in determining the spectrum of the temperature fluctuations imprinted on the Cosmic Background Radiation (CBR) some 400 thousand years later. Using deuterium as a baryometer and helium-4 as a chronometer, the predictions of BBN and the CBR are compared to observations. The successes of, as well as challenges to the standard models of particle physics and cosmology are identified. While systematic uncertainties may be the source of some of the current tensions, it could be that the data are pointing the way to new physics. In particular, BBN and the CBR are used to address the questions of whether or not the relic neutrinos were fully populated in the early universe and, to limit the magnitude of any lepton asymmetry which may be concealed in the neutrinos.Comment: Accepted for publication in the Proceedings of Nobel Symposium 129, "Neutrino Physics"; to appear in Physics Scripta, eds., L Bergstrom, O. Botner, P. Carlson, P. O. Hulth, and T. Ohlsso

The Cosmological Evolution of the Average Mass Per Baryon

Subsequent to the early Universe quark-hadron transition the universal baryon number is carried by nucleons: neutrons and protons. The total number of nucleons is preserved as the Universe expands, but as it cools lighter protons are favored over heavier neutrons reducing the average mass per baryon. During primordial nucleosynthesis free nucleons are transformed into bound nuclides, primarily helium, and the nuclear binding energies are radiated away, further reducing the average mass per baryon. In particular, the reduction in the average mass per baryon resulting from Big Bang Nucleosynthesis (BBN) modifies the numerical factor relating the baryon (nucleon) mass and number densities. Here the average mass per baryon, m_B, is tracked from the early Universe to the present. The result is used to relate the present ratio of baryons to photons (by number) to the present baryon mass density at a level of accuracy commensurate with that of recent cosmological data, as well as to estimate the energy released during post-BBN stellar nucleosynthesis.Comment: 5 pages; no figures; updated references; final version published in JCAP, 10 (2006) 01

Palynofacies classification of the depositional elements of confined turbidite systems : Examples from the Gres d'Annot, SE France

Acknowledgements We thank BG Brasil for financial support for this project and permission to publish. BG Group is a wholly owned subsidiary of Royal Dutch Shell. McArthur is grateful to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for the scholarship 049/2012. The Agência Nacional do Petróleo (ANP) are thanked for supporting this project. Massimo Zecchin is thanked for handling this paper and Roberto Tinterri is thanked for his constructive review, in addition to an anonymous reviewer.Peer reviewedPostprin

Diffusion and jump-length distribution in liquid and amorphous Cu33_{33}Zr67_{67}

Using molecular dynamics simulation, we calculate the distribution of atomic jum ps in Cu$_{33}$Zr$_{67}$ in the liquid and glassy states. In both states the distribution of jump lengths can be described by a temperature independent exponential of the length and an effective activation energy plus a contribution of elastic displacements at short distances. Upon cooling the contribution of shorter jumps dominates. No indication of an enhanced probability to jump over a nearest neighbor distance was found. We find a smooth transition from flow in the liquid to jumps in the g lass. The correlation factor of the diffusion constant decreases with decreasing temperature, causing a drop of diffusion below the Arrhenius value, despite an apparent Arrhenius law for the jump probability

Crustal distribution in the central Gulf of Mexico from an integrated geophysical analysis

This study addresses the question of the crustal composition in the central part of the northern Gulf of Mexico (GOM) – the region of the major disagreement between published tectonic models. The location of the Ocean-Continental Boundary (OCB) for different tectonic models varies within 140 km (87 mi) in the study area. I have developed a 2D model integrating the seismic reflection and refraction data with potential fields (gravity and magnetics) along the profile through the debated region. Two alternative OCB locations were tested. The preferred model suggests the OCB position near the Sigsbee Escarpment, which is in agreement with the result of Eddy, 2014 and with the findings of the LithoSPAN experiment (Makris et al, 2015). However, the model with an alternative OCB location (further to the north of the Sigsbee Escarpment) may also satisfy the observed gravity and magnetic fields, although the crust in the oceanic domain is thicker than normal. Since the potential fields do not offer the unique answer, the other geophysical data should be examined, such as the Vp/Vs ratio. This parameter was analyzed for the LithoSPAN (Makris et al., 2015) and allowed distinguishing between continental and oceanic domains; it was also examined for GUMBO 3 and 4 (Duncan, 2013). However, the values of Vs derived during retraction experiment for GUMBO 2 are not publically available at this time