Unitarity of the Leptonic Mixing Matrix

We determine the elements of the leptonic mixing matrix, without assuming unitarity, combining data from neutrino oscillation experiments and weak decays. To that end, we first develop a formalism for studying neutrino oscillations in vacuum and matter when the leptonic mixing matrix is not unitary. To be conservative, only three light neutrino species are considered, whose propagation is generically affected by non-unitary effects. Precision improvements within future facilities are discussed as well.Comment: Standard Model radiative corrections to the invisible Z width included. Some numerical results modified at the percent level. Updated with latest bounds on the rare tau decay. Physical conculsions unchange

Renormalization of chiral two pion exchange NN interactions with delta excitations: correlations in the partial wave expansion

In this work we consider the renormalization of the chiral two-pion exchange potential with explicit delta-excitations for nucleon-nucleon scattering at next-to-leading (NLO) and next-to-next-to-leading order (N2LO). Due to the singular nature of the chiral potentials, correlations between different partial waves are generated. In particular we show that two-body scattering by a short distance power like singular attractive interaction can be renormalized in all partial waves with a single counterterm, provided the singularities are identical. A parallel statement holds in the presence of tensor interactions when the eigenpotentials in the coupled channel problem also coincide. While this construction reduces the total number of counterterms to eleven in the case of nucleon-nucleon scattering with chiral two-pion exchange interactions with delta degrees of freedom, the differences in the scattering phases as compared to the case with the uncorrelated partial wave renormalization become smaller as the angular momentum is increased in the elastic scattering region.Comment: 20 pages, 8 figures, a section has been added discussing cut-off dependence. Accepted for publication in PR

Generalized Hamilton-Jacobi equations for nonholonomic dynamics

Employing a suitable nonlinear Lagrange functional, we derive generalized Hamilton-Jacobi equations for dynamical systems subject to linear velocity constraints. As long as a solution of the generalized Hamilton-Jacobi equation exists, the action is actually minimized (not just extremized)

Causal Relativistic Fluid Dynamics

We derive causal relativistic fluid dynamical equations from the relaxation model of kinetic theory as in a procedure previously applied in the case of non-relativistic rarefied gases. By treating space and time on an equal footing and avoiding the iterative steps of the conventional Chapman-Enskog --- CE---method, we are able to derive causal equations in the first order of the expansion in terms of the mean flight time of the particles. This is in contrast to what is found using the CE approach. We illustrate the general results with the example of a gas of identical ultrarelativistic particles such as photons under the assumptions of homogeneity and isotropy. When we couple the fluid dynamical equations to Einstein's equation we find, in addition to the geometry-driven expanding solution of the FRW model, a second, matter-driven nonequilibrium solution to the equations. In only the second solution, entropy is produced at a significant rate.Comment: 23 pages (CQG, in press

EURONU WP6 2009 yearly report: Update of the physics potential of Nufact, superbeams and betabeams

Many studies in the last ten years have shown that we can measure the unknown angle theta13, discover leptonic CP violation and determine the neutrino hierarchy in more precise neutrino oscillation experiments, searching for the subleading channel nue -> numu in the atmospheric range. In this first report of WP6 activities the following new results are reviewed: (1) Re-evaluation of the physics reach of the upcoming generation of experiments to measure theta13 and delta; (2) New tools to explore a larger parameter space as needed beyond the standard scenario; (3) Neutrino Factory: (a) evaluation of the physics reach of a Nufact regards sterile neutrinos; (b) evaluation of the physics reach of a Nufact as regards non-standard interactions; (c) evaluation of the physics reach of a Nufact as regards violation of unitarity; (d) critical assessment on long baseline tau-detection at Nufact; (e) new physics searches at a near detector in a Nufact; (4) Beta-beams: (a) choice of ions and location for a gamma = 100 CERN-based beta-beam; (b) re-evaluation of atmospheric neutrino background for the gamma = 100 beta-beam scenario; (c) study of a two baseline beta-beam; (d) measuring absolute neutrino mass with beta-beams; (e) progress on monochromatic beta-beams; (5) Update of the physics potential of the SPL super-beam. Eventually, we present an updated comparison of the sensitivity to theta13, delta and the neutrino mass hierarchy of several of the different proposed facilities.Comment: 2009 Yearly report of the Working Package 6 (Physics) of the EUROnu FP7 EU project. 55 pages, 21 figures

Extremal flows in Wasserstein space

We develop an intrinsic geometric approach to the calculus of variations in theWasserstein space. We show that the flows associated with the Schr\ua8odinger bridge with general prior, with optimal mass transport, and with the Madelung fluid can all be characterized as annihilating the first variation of a suitable action. We then discuss the implications of this unified framework for stochastic mechanics: It entails, in particular, a sort of fluid-dynamic reconciliation between Bohm\u2019s and Nelson\u2019s stochastic mechanics

Holographic Dark Energy with Curvature

In this paper we consider an holographic model of dark energy, where the length scale is the Hubble radius, in a non flat geometry. The model contains the possibility to alleviate the cosmic coincidence problem, and also incorporate a mechanism to obtain the transition from decelerated to an accelerated expansion regime. We derive an analytic form for the Hubble parameter in a non flat universe, and using it, we perform a Bayesian analysis of this model using SNIa, BAO and CMB data. We find from this analysis that the data favored a small value for $\Omega_k$, however high enough to still produce cosmological consequences.Comment: 6 pages, 2 figure

EUROnu-WP6 2010 Report

This is a summary of the work done by the Working Package 6 (Physics) of the EU project "EUROnu" during the second year of activity of the project.Comment: 82 pages, 51 eps figure

Cosmological entropy and generalized second law of thermodynamics in F(R,G)F(R,G) theory of gravity

We consider a spatially flat Friedmann-Lemaitre-Robertson-Walker space time and investigate the second law and the generalized second law of thermodynamics for apparent horizon in generalized modified Gauss Bonnet theory of gravity (whose action contains a general function of Gauss Bonnet invariant and the Ricci scalar: $F(R,G)$). By assuming that the apparent horizon is in thermal equilibrium with the matter inside it, conditions which must be satisfied by $F(R,G)$ are derived and elucidated through two examples: a quasi-de Sitter space-time and a universe with power law expansion.Comment: 10 pages, minor changes, typos corrected, accepted for publication in Europhysics Letter

Attenuation and damping of electromagnetic fields: Influence of inertia and displacement current

New results for attenuation and damping of electromagnetic fields in rigid conducting media are derived under the conjugate influence of inertia due to charge carriers and displacement current. Inertial effects are described by a relaxation time for the current density in the realm of an extended Ohm's law. The classical notions of poor and good conductors are rediscussed on the basis of an effective electric conductivity, depending on both wave frequency and relaxation time. It is found that the attenuation for good conductors at high frequencies depends solely on the relaxation time. This means that the penetration depth saturates to a minimum value at sufficiently high frequencies. It is also shown that the actions of inertia and displacement current on damping of magnetic fields are opposite to each other. That could explain why the classical decay time of magnetic fields scales approximately as the diffusion time. At very small length scales, the decay time could be given either by the relaxation time or by a fraction of the diffusion time, depending whether inertia or displacement current, respectively, would prevail on magnetic diffusion.Comment: 21 pages, 1 figur