863 research outputs found
Root systems from Toric Calabi-Yau Geometry. Towards new algebraic structures and symmetries in physics?
The algebraic approach to the construction of the reflexive polyhedra that
yield Calabi-Yau spaces in three or more complex dimensions with K3 fibres
reveals graphs that include and generalize the Dynkin diagrams associated with
gauge symmetries. In this work we continue to study the structure of graphs
obtained from reflexive polyhedra. We show how some particularly defined
integral matrices can be assigned to these diagrams. This family of matrices
and its associated graphs may be obtained by relaxing the restrictions on the
individual entries of the generalized Cartan matrices associated with the
Dynkin diagrams that characterize Cartan-Lie and affine Kac-Moody algebras.
These graphs keep however the affine structure, as it was in Kac-Moody Dynkin
diagrams. We presented a possible root structure for some simple cases. We
conjecture that these generalized graphs and associated link matrices may
characterize generalizations of these algebras.Comment: 24 pages, 6 figure
The Classification of the Simply Laced Berger Graphs from Calabi-Yau spaces
The algebraic approach to the construction of the reflexive polyhedra that
yield Calabi-Yau spaces in three or more complex dimensions with K3 fibres
reveals graphs that include and generalize the Dynkin diagrams associated with
gauge symmetries. In this work we continue to study the structure of graphs
obtained from reflexive polyhedra. The objective is to describe the
``simply laced'' cases, those graphs obtained from three dimensional spaces
with K3 fibers which lead to symmetric matrices. We study both the affine and,
derived from them, non-affine cases. We present root and weight structurea for
them. We study in particular those graphs leading to generalizations of the
exceptional simply laced cases and . We show how
these integral matrices can be assigned: they may be obtained by relaxing the
restrictions on the individual entries of the generalized Cartan matrices
associated with the Dynkin diagrams that characterize Cartan-Lie and affine
Kac-Moody algebras. These graphs keep, however, the affine structure present in
Kac-Moody Dynkin diagrams. We conjecture that these generalized simply laced
graphs and associated link matrices may characterize generalizations of
Cartan-Lie and affine Kac-Moody algebras
KamLAND Bounds on Solar Antineutrinos and neutrino transition magnetic moments
We investigate the possibility of detecting solar electron antineutrinos with
the KamLAND experiment. These electron antineutrinos are predicted by
spin-flavor oscillations at a significant rate even if this mechanism is not
the leading solution to the SNP. KamLAND is sensitive to antineutrinos
originated from solar B neutrinos. From KamLAND negative results after
145 days of data taking, we obtain model independent limits on the total flux
of solar electron antineutrinos $\Phi({}^8 B)< 1.1-3.5\times 10^4 cm^{-2}\
s^{-1}P<0.15%\mu B< 2.3\times 10^{-21}(\Delta m^2, \tan^2\theta)\mu\lsim 3.9\times 10^{-12} \mu_BB= 50\mu\lsim 9.0\times 10^{-13} \mu_BB= 200\mu\lsim 2.0\times 10^{-13} \mu_BB= 1000$ kG at the same
statistical significance.Comment: 13 pages, 2 figure
Muon anomalous magnetic moment in supersymmetric scenarios with an intermediate scale and nonuniversality
We analyze the anomalous magnetic moment of the muon (a_{\mu}) in
supersymmetric scenarios. First we concentrate on scenarios with universal soft
terms. We find that a moderate increase of a_{\mu} can be obtained by lowering
the unification scale M_{GUT} to intermediate values 10^{10-12} GeV. However,
large values of \tan \beta are still favored. Then we study the case of
non-universal soft terms. For the usual value M_{GUT}~10^{16} GeV, we obtain
a_{\mu} in the favored experimental range even for moderate \tan \beta regions
\tan\beta ~ 5$. Finally, we give an explicit example of these scenarios. In
particular, we show that in a D-brane model, where the string scale is
naturally of order 10^{10-12} GeV and the soft terms are non universal, a_{\mu}
is enhanced with low \tan\beta.Comment: Final version to appear in Phys. Rev. D. Conventions clarified,
results in the figures improve
Procesos de incorporación y preservación de bioclastos en flujos piroclásticos subacuáticos: dos ejemplis y un modelo genético
Se ofrecen dos ejemplos de incorporación de bioclastos por parte de coladas piroclásticas en ambiente subacuático. Estos ejemplos proceden del Ordovicico Superior-Silúrico inferior del Sarrabus (Sureste de Cerdeña, Italia) y el Mioceno del Arcuentu (Suroeste de Cerdeña, Italia). Los bioclastos aparecen en ambos casos en el frente de coladas piroclásticas, y se han preservádo en forma de moldes. Tras una exposición detallada de los materiales se propone un modelo genético común para ambos ejemplos, en el que tras la asimilación de los bioclastos en el frente de la colada éstos sufren disolución y se preservan en los raros casos en los que la colada piroclástica se enfrió rápidamente
Procesos de incorporación y preservación de bioclastos en flujos piroclásticos subacuáticos: dos ejemplis y un modelo genético
Se ofrecen dos ejemplos de incorporación de bioclastos por parte de coladas piroclásticas en ambiente subacuático. Estos ejemplos proceden del Ordovicico Superior-Silúrico inferior del Sarrabus (Sureste de Cerdeña, Italia) y el Mioceno del Arcuentu (Suroeste de Cerdeña, Italia). Los bioclastos aparecen en ambos casos en el frente de coladas piroclásticas, y se han preservádo en forma de moldes. Tras una exposición detallada de los materiales se propone un modelo genético común para ambos ejemplos, en el que tras la asimilación de los bioclastos en el frente de la colada éstos sufren disolución y se preservan en los raros casos en los que la colada piroclástica se enfrió rápidamente
Prison de-radicalization strategies, programs and risk assessment tools in Europe
open3noWith financial support from the Criminal Justice Programme of the European Union
Call: JUST-AG-2016-03
Project Number: 763710
Project Acronym: PRP
Duration (months): 24 Project
Title: European Prison Observatory. Prison de-radicalization strategies, programmes and risk assessment tools in Europe.
Coordinator: ANTIGONE ONLUS
Alvise Sbraccia wrote the Part One of this Report;
Daniela Ronco wrote Part Two, chapters 1, 2, 3, 4, 5, 6, 7, 8;
Giovanni Torrente wrote Part Two, chapters 9-10.
The conclusions have been written by all the authorsThis project’s goal is to assess strategies and programmes which prevent, deter and counter radicalization in prison and identify and analyse good practices regarding new or existing de-radicalization, disengagement and rehabilitation programmes and risk assessment tools. The analysis has been carried out having in mind the international and European standards for the the protection of detainees' rights. Research incorporates qualitative and quantitative data analysis on official government documents and interviews with stakeholders from prison administration and management, prison staff, Imams, chaplains and other religious representatives.openDaniela Ronco, Alvise Sbraccia, Giovanni TorrenteDaniela Ronco, Alvise Sbraccia, Giovanni Torrent
Neutrino Magnetic Moments and Minimal Supersymmetric SO(10) Model
We examine supersymmetric contributions to transition magnetic moments of
Majorana neutrinos. We first give the general formula for it. In concrete
evaluations, informations of neutrino mass matrix elements including CP phases
are necessary. Using unambiguously determined neutrino mass matrices in
recently proposed minimal supersymmetric SO(10) model, the transition magnetic
moments are calculated. The resultant neutrino magnetic moments are found to be
roughly an order of magnitude larger than those calculated in the standard
model extended to incorporate the see-saw mechanism.Comment: 8 pages, 4 figures, the version to be published in International
Journal of Modern Physics
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