6,304 research outputs found
Constraints on Natural MNS Parameters from |U_e3|
The MNS matrix structure emerging as a result of recent neutrino measurements
strongly suggests two large mixing angles (solar and atmospheric) and one small
angle (|U_e3| << 1). Especially when combined with the neutrino mass hierarchy,
these values turn out to impose rather stringent constraints on possible flavor
models connecting the three active fermion generations. Specifically, we show
that an extremely small value of |U_e3| would require fine tuning of Majorana
mass matrix parameters, particularly in the context of seesaw models.Comment: 21 pages, ReVTeX, 2 .eps figure files, updated references and
acknowledgment
Co-evolution of RDF Datasets
Linking Data initiatives have fostered the publication of large number of RDF
datasets in the Linked Open Data (LOD) cloud, as well as the development of
query processing infrastructures to access these data in a federated fashion.
However, different experimental studies have shown that availability of LOD
datasets cannot be always ensured, being RDF data replication required for
envisioning reliable federated query frameworks. Albeit enhancing data
availability, RDF data replication requires synchronization and conflict
resolution when replicas and source datasets are allowed to change data over
time, i.e., co-evolution management needs to be provided to ensure consistency.
In this paper, we tackle the problem of RDF data co-evolution and devise an
approach for conflict resolution during co-evolution of RDF datasets. Our
proposed approach is property-oriented and allows for exploiting semantics
about RDF properties during co-evolution management. The quality of our
approach is empirically evaluated in different scenarios on the DBpedia-live
dataset. Experimental results suggest that proposed proposed techniques have a
positive impact on the quality of data in source datasets and replicas.Comment: 18 pages, 4 figures, Accepted in ICWE, 201
Opportunistic linked data querying through approximate membership metadata
Between URI dereferencing and the SPARQL protocol lies a largely unexplored axis of possible interfaces to Linked Data, each with its own combination of trade-offs. One of these interfaces is Triple Pattern Fragments, which allows clients to execute SPARQL queries against low-cost servers, at the cost of higher bandwidth. Increasing a client's efficiency means lowering the number of requests, which can among others be achieved through additional metadata in responses. We noted that typical SPARQL query evaluations against Triple Pattern Fragments require a significant portion of membership subqueries, which check the presence of a specific triple, rather than a variable pattern. This paper studies the impact of providing approximate membership functions, i.e., Bloom filters and Golomb-coded sets, as extra metadata. In addition to reducing HTTP requests, such functions allow to achieve full result recall earlier when temporarily allowing lower precision. Half of the tested queries from a WatDiv benchmark test set could be executed with up to a third fewer HTTP requests with only marginally higher server cost. Query times, however, did not improve, likely due to slower metadata generation and transfer. This indicates that approximate membership functions can partly improve the client-side query process with minimal impact on the server and its interface
Systematic perturbation calculation of integrals with applications to physics
In this paper we generalize and improve a method for calculating the period
of a classical oscillator and other integrals of physical interest, which was
recently developed by some of the authors. We derive analytical expressions
that prove to be more accurate than those commonly found in the literature, and
test the convergence of the series produced by the approach.Comment: 11 pages, 5 figure
Regional initiative for the evaluation of Queen Conch (Strombus gigas) exploitation under an historical perspective
Supersymmetric Flavor Models and the B --> phi K_S Anomaly
We consider the flavor structure of supersymmetric theories that can account
for the deviation of the observed time-dependent CP asymmetry in B --> phi K_S
from the standard model prediction. Assuming simple flavor symmetries and
effective field theory, we investigate possible correlations between sizable
supersymmetric contributions to b --> s transitions and to flavor changing
processes that are more tightly constrained. With relatively few assumptions,
we determine the properties of minimal Yukawa and soft mass textures that are
compatible with the desired supersymmetric flavor-changing effect and
constraints. We then present explicit models that are designed (at least
approximately) to realize these textures. In particular, we present an Abelian
model based on a single U(1) factor and a non-trivial extra-dimensional
topography that can explain the CP asymmetry in B --> phi K_S, while
suppressing other supersymmetric flavor changing effects through a high degree
of squark-quark alignment.Comment: 18 pages LaTeX, 3 eps figure
A new method for the solution of the Schrodinger equation
We present a new method for the solution of the Schrodinger equation
applicable to problems of non-perturbative nature. The method works by
identifying three different scales in the problem, which then are treated
independently: An asymptotic scale, which depends uniquely on the form of the
potential at large distances; an intermediate scale, still characterized by an
exponential decay of the wave function and, finally, a short distance scale, in
which the wave function is sizable. The key feature of our method is the
introduction of an arbitrary parameter in the last two scales, which is then
used to optimize a perturbative expansion in a suitable parameter. We apply the
method to the quantum anharmonic oscillator and find excellent results.Comment: 4 pages, 4 figures, RevTex
U(2)-like Flavor Symmetries and Approximate Bimaximal Neutrino Mixing
Models involving a U(2) flavor symmetry, or any of a number of its
non-Abelian discrete subgroups, can explain the observed hierarchy of charged
fermion masses and CKM angles. It is known that a large neutrino mixing angle
connecting second and third generation fields may arise via the seesaw
mechanism in these models, without a fine tuning of parameters. Here we show
that it is possible to obtain approximate bimaximal mixing in a class of models
with U(2)-like Yukawa textures. We find a minimal form for Dirac and Majorana
neutrino mass matrices that leads to two large mixing angles, and show that our
result can quantitatively explain atmospheric neutrino oscillations while
accommodating the favored, large angle MSW solution to the solar neutrino
problem. We demonstrate that these textures can arise in models by presenting a
number of explicit examples.Comment: 20 pages RevTex4, 2 figure
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