Four species neutrino oscillations at ν\nu-Factory: sensitivity and CP-violation

The prospects of measuring the leptonic angles and CP-odd phases at a {\em neutrino factory} are discussed in the scenario of three active plus one sterile neutrino. We consider the \nu_\mu \raw \nu_e LSND signal. Its associated large mass difference leads to observable neutrino oscillations at short ($\sim 1$ km) baseline experiments. Sensitivities to the leptonic angles down to $10^{-3}$ can be easily achieved with a 1 Ton detector. Longer baseline experiments ($\sim 100$ km) with a 1 Kton detector can provide very clean tests of CP-violation especially through tau lepton detection.Comment: 15 pages, LaTeX2e, 14 eps files, use package epsfi

Nuclear mass systematics by complementing the Finite Range Droplet Model with neural networks

A neural-network model is developed to reproduce the differences between experimental nuclear mass-excess values and the theoretical values given by the Finite Range Droplet Model. The results point to the existence of subtle regularities of nuclear structure not yet contained in the best microscopic/phenomenological models of atomic masses. Combining the FRDM and the neural-network model, we create a hybrid model with improved predictive performance on nuclear-mass systematics and related quantities.Comment: Proceedings for the 15th Hellenic Symposium on Nuclear Physic

Physics potential at a neutrino factory: can we benefit from more than just detecting muons?

In order to fully address the oscillation processes at a neutrino factory, a detector should be capable of identifying and measuring all three charged lepton flavors produced in charged current interactions {\it and} of measuring their charges to discriminate the incoming neutrino helicity. This is an experimentally challenging task, given the required detector mass for long-baseline experiments. We address the benefit of a high-granularity, excellent-calorimetry non-magnetized target-detector, which provides a background-free identification of electron neutrino charged current and a kinematical selection of tau neutrino charged current interactions. We assume that charge discrimination is only available for muons reaching an external magnetized-Fe spectrometer. This allows the clean classification of events into electron, right-sign muon, wrong-sign muon and no-lepton categories. In addition, high granularity permits a clean detection of quasi-elastic events, which by detecting the final state proton, provide a selection of the neutrino electron helicity without the need of an electron charge measurement. From quantitative analyses of neutrino oscillation scenarios, we conclude that in many cases the discovery sensitivities and the measurements of the oscillation parameters are dominated by the ability to measure the muon charge. However, we identify cases where identification of electron and tau samples contributes significantly.Comment: 39 page

Medieval Nemea: Building a Public Digital Resource

This site presents medieval ceramics from the excavations at the site of Nemea, in southern Greece. We have created a digital resource with results and artifacts from archaeological excavations conducted in the 1970s and 1980s, which have remained unpublished. The website incorporates a variety of materials, including excavation notebooks, maps, data bases, photographs, and 3D models of ceramics. Omeka was selected as the software for this project for several reasons. Omeka offers the Dublin Core metadata as a way to standardize and organize digital data, allowing its users access to a well-developed platform. Omeka is also an open source software allowing anyone to build and access digital resources, as well as the opportunity to share cultural heritage resources worldwide. Lastly, plugins are useful tools which allow users to broaden the fundamental functionality of Omeka. As digital technologies progress, so will our abilities to enhance this digital resource. Although Omeka was created for a 2D environment, we anticipate that soon it will offer tools that will allow the incorporation of 3D data. In the near future, we plan to create an open forum and invite comments and suggestions from users for improvements of this digital resource. Another addition will be to create a ‘How-to E-book’ page that will explain the process and the steps that we have followed, and make the addition of new content easy and user-friendly. Finally, resources such as this strengthen the connection between research, heritage and preservation, by broadening participation and making accessible material that previously had been available only to specialists

Degenerate Dirac Neutrinos

A simple extension of the standard model is proposed in which all the three generations of neutrinos are Dirac particles and are naturally light. We then assume that the neutrino mass matrix is diagonal and degenerate, with a few eV mass to solve the dark matter problem. The self energy radiative corrections, however, remove this degeneracy and allow mixing of these neutrinos. The electroweak radiative corrections then predict a lower bound on the $\nu_\mu - \nu_e$ mass difference which solves the solar neutrino problem through MSW mechanism and also predict a lower bound on the $\nu_\tau - \nu_\mu$ mass difference which is just enough to explain the atmospheric neutrino problem as reported by super Kamiokande.Comment: 11 pages latex fil

The role of ν\nu-induced reactions on lead and iron in neutrino detectors

We have calculated cross sections and branching ratios for neutrino induced reactions on ^{208}Pb and ^{56}Fe for various supernova and accelerator-relevant neutrino spectra. This was motivated by the facts that lead and iron will be used on one hand as target materials in future neutrino detectors, on the other hand have been and are still used as shielding materials in accelerator-based experiments. In particular we study the inclusive ^{56}$Fe(\nu_e,e^-)$^{56}Co and ^{208}$Pb(\nu_e,e^-)$^{208}Bi cross sections and calculate the neutron energy spectra following the decay of the daughter nuclei. These reactions give a potential background signal in the KARMEN and LSND experiment and are discussed as a detection scheme for supernova neutrinos in the proposed OMNIS and LAND detectors. We also study the neutron-emission following the neutrino-induced neutral-current excitation of ^{56}Fe and ^{208}Pb.Comment: 23 pages (including 7 figures

Near-optimal asymmetric binary matrix partitions

We study the asymmetric binary matrix partition problem that was recently introduced by Alon et al. (WINE 2013) to model the impact of asymmetric information on the revenue of the seller in take-it-or-leave-it sales. Instances of the problem consist of an $n \times m$ binary matrix $A$ and a probability distribution over its columns. A partition scheme $B=(B_1,...,B_n)$ consists of a partition $B_i$ for each row $i$ of $A$. The partition $B_i$ acts as a smoothing operator on row $i$ that distributes the expected value of each partition subset proportionally to all its entries. Given a scheme $B$ that induces a smooth matrix $A^B$, the partition value is the expected maximum column entry of $A^B$. The objective is to find a partition scheme such that the resulting partition value is maximized. We present a $9/10$-approximation algorithm for the case where the probability distribution is uniform and a $(1-1/e)$-approximation algorithm for non-uniform distributions, significantly improving results of Alon et al. Although our first algorithm is combinatorial (and very simple), the analysis is based on linear programming and duality arguments. In our second result we exploit a nice relation of the problem to submodular welfare maximization.Comment: 17 page

Off-diagonal structure of neutrino mass matrix in see-saw mechanism and electron-muon-tau lepton universality

By a simple extension of the standard model in which ($e-\mu -\tau$) universality is not conserved, we present a scenario within the framework of see-saw mechanism in which the neutrino mass matrix is strictly off-diagonal in the flavor basis. We show that a version of this scenario can accomodate the atmospheric $\nu_\mu -\nu_\tau$ neutrino oscillations and $\nu_\mu -\nu_e$ oscillations claimed by the LSND collaboration. PACS: 14.60.Pq; 14.60.St;13.15.+gComment: 5 pages, Revtex, 1 figure: The model accomodate another version which explains atmospheric neutrino data and the observed solar neutrino oscillations (large angle solution). In the previous version the value of \lambda parameter is changed to the expected one. This version now accomodates LSND result and solar neutrino oscillations (small angle MSW solution