Untangling supernova-neutrino oscillations with beta-beam data

Recently, we suggested that low-energy beta-beam neutrinos can be very useful for the study of supernova neutrino interactions. In this paper, we examine the use of a such experiment for the analysis of a supernova neutrino signal. Since supernova neutrinos are oscillating, it is very likely that the terrestrial spectrum of supernova neutrinos of a given flavor will not be the same as the energy distribution with which these neutrinos were first emitted. We demonstrate the efficacy of the proposed method for untangling multiple neutrino spectra. This is an essential feature of any model aiming at gaining information about the supernova mechanism, probing proto-neutron star physics, and understanding supernova nucleosynthesis, such as the neutrino process and the r-process. We also consider the efficacy of different experimental approaches including measurements at multiple beam energies and detector configurations.Comment: 13 pages, 11 figures, accepted for publication in Phys. Rev.

Simulation of a Brownian particle in an optical trap

Cataloged from PDF version of article.Unlike passive Brownian particles, active Brownian particles, also known as microswimmers, propel themselves with directed motion and thus drive themselves out of equilibrium. Understanding their motion can provide insight into out-of-equilibrium phenomena associated with biological examples such as bacteria, as well as with artificial microswimmers. We discuss how to mathematically model their motion using a set of stochastic differential equations and how to numerically simulate it using the corresponding set of finite difference equations both in homogenous and complex environments. In particular, we show how active Brownian particles do not follow the Maxwell-Boltzmann distribution-a clear signature of their out-of-equilibrium nature- and how, unlike passive Brownian particles, microswimmers can be funneled, trapped, and sorted. (C) 2014 American Association of Physics Teachers

Low energy neutrino scattering measurements at future Spallation Source facilities

In the future several Spallation Source facilities will be available worldwide. Spallation Sources produce large amount of neutrinos from decay-at-rest muons and thus can be well adapted to accommodate state-of-the-art neutrino experiments. In this paper low energy neutrino scattering experiments that can be performed at such facilities are reviewed. Estimation of expected event rates are given for several nuclei, electrons and protons at a detector located close to the source. A neutrino program at Spallation Sources comprises neutrino-nucleus cross section measurements relevant for neutrino and core-collapse supernova physics, electroweak tests and lepton-flavor violation searches.Comment: 12 pages, 4 figures, 5 table

Sun tracker with rotatable plane-parallel plate and two photocells Patent

Sun tracker with rotatable plane-parallel plate and two photocell

The analysis and design of transonic two-element airfoil systems

The multiphase effort in the development of tools for the analysis and design of two-element airfoil systems, that is, airfoils with a slat or a flap at transonic speeds is described. The first phase involved the development of a method to compute the inviscid flow over such configurations. In the second phase the inviscid code was coupled to a boundary layer calculation program in order to compute the loss in performance due to viscous effects. An inverse code that constructs the airfoil system corresponding to a desired pressure distribution is described

Active Brownian Motion Tunable by Light

Active Brownian particles are capable of taking up energy from their environment and converting it into directed motion; examples range from chemotactic cells and bacteria to artificial micro-swimmers. We have recently demonstrated that Janus particles, i.e. gold-capped colloidal spheres, suspended in a critical binary liquid mixture perform active Brownian motion when illuminated by light. In this article, we investigate in some more details their swimming mechanism leading to active Brownian motion. We show that the illumination-borne heating induces a local asymmetric demixing of the binary mixture generating a spatial chemical concentration gradient, which is responsible for the particle's self-diffusiophoretic motion. We study this effect as a function of the functionalization of the gold cap, the particle size and the illumination intensity: the functionalization determines what component of the binary mixture is preferentially adsorbed at the cap and the swimming direction (towards or away from the cap); the particle size determines the rotational diffusion and, therefore, the random reorientation of the particle; and the intensity tunes the strength of the heating and, therefore, of the motion. Finally, we harness this dependence of the swimming strength on the illumination intensity to investigate the behaviour of a micro-swimmer in a spatial light gradient, where its swimming properties are space-dependent

Simulation of the active Brownian motion of a microswimmer

Cataloged from PDF version of article.Unlike passive Brownian particles, active Brownian particles, also known as microswimmers, propel themselves with directed motion and thus drive themselves out of equilibrium. Understanding their motion can provide insight into out-of-equilibrium phenomena associated with biological examples such as bacteria, as well as with artificial microswimmers. We discuss how to mathematically model their motion using a set of stochastic differential equations and how to numerically simulate it using the corresponding set of finite difference equations both in homogenous and complex environments. In particular, we show how active Brownian particles do not follow the Maxwell-Boltzmann distribution-a clear signature of their out-of-equilibrium nature- and how, unlike passive Brownian particles, microswimmers can be funneled, trapped, and sorted. (C) 2014 American Association of Physics Teachers

Neutrino-nucleus interaction rates at a low-energy beta-beam facility

We compute the neutrino detection rates to be expected at a low-energy beta-beam facility. We consider various nuclei as neutrino detectors and compare the case of a small versus large storage ring.Comment: 6 pages, 3 figure

A dynamical collective calculation of supernova neutrino signals

We present the first calculations with three flavors of collective and shock wave effects for neutrino propagation in core-collapse supernovae using hydroynamical density profiles and the S matrix formalism. We explore the interplay between the neutrino-neutrino interaction and the effects of multiple resonances upon the time signal of positrons in supernova observatories. A specific signature is found for the inverted hierarchy and a large third neutrino mixing angle and we predict, in this case, a dearth of lower energy positrons in Cherenkov detectors midway through the neutrino signal and the simultaneous revelation of valuable information about the original fluxes. We show that this feature is also observable with current generation neutrino detectors at the level of several sigmas.Comment: 4 pages, 5 figure

Lane, pecore e pastori in Puglia fra Tardoantico e Medioevo: novità dai dati archeozoologici

This paper deals with the bioarchaeological researches on ovine transhumance in Apulia from the Late Antiquity to the Medieval Age, with particular regard to the contribution of the zooarchaeological researches. By integrating historical, epigraphic, archaeological and bioarchaeological data it is now possible to re-enact the development and the characters of the sheep/goat movements and the transhumance products, such as wool and milk, from the 4th to the 15th c. A.D. Archaeobotanical and archaeoantropological data indicate that Apulian landscape was characterized by uncultivated areas (woods, marshlands or pasture) from Roman to the Late Antique Ages; zooarchaeological analysis propose the continuity of sheep/goat breeding until the Middle Ages, in spite of some changes, with a prevalent and continuous wool production activity. In this way the study of faunal remains can integrate the knowledge by new evaluation elements such as the mortality and the periodical slaughtering, with regard to the identification of the species in a specific territorial context and the breeding purposes. Besides the mortality data also the sexual distinction is important; a constant element is the ovine prevalence in the sheep/goat flock composition. Taking into consideration the pastoral practice from the Late Antiquity to the Middle Ages it is possible to pick out some elements that are compatible with a transhumant management of the flocks, such as a general staging post of the size on medium-big one and the above average recorded in other Italian and European sites