43 research outputs found
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Is Cognitive Neuropsychology Plausible? The Perils of Sitting on a One-Legged Stool
We distinguish between strong and weak cognitive neuropsychology, with the former attempting to provide direct insights into the nature of information processing and the latter having the more modest goal of providing constraints on such theories. We argue that strong cognitive neuropsychology, although possible, is unlikely to succeed and that researchers will fare better by combining behavioral, computational, and neural investigations. Arguments offered by Caramazza (1992) in defense of strong neuropsychology are analyzed, and examples are offered to illustrate the power of alternative points of view.Psycholog
Hostility is associated with self-reported cognitive and social benefits across Massively Multiplayer Online Role-Playing Game player-roles
Tree Level Metastability and Gauge Mediation in Baryon Deformed SQCD
We investigate supersymmetric QCD with gauge group SU(2) and a baryon
deformation to the superpotential. The existence of an uplifted vacuum at the
origin with tree level metastability is demonstrated. When this model is
implemented in a direct gauge mediation scenario we therefore find gaugino
masses which are comparable to sfermion masses and parameterised by an
effective number of messengers 1/8. All deformations are well motivated by
appealing to the electric theory and an R-symmetry. This R-symmetry is
explicitly broken by the same term responsible for supersymmetry breaking.
Moreover, the model does not suffer from the Landau pole problem and we find
that it can be described in terms of just two scales: the weak scale and a high
scale like the Planck or GUT scale. The model can be tested by searching for
new particles at the TeV scale charged under the visible sector gauge group.Comment: 17 pages, 7 figures, updated reference
Vacuum stability and the Cholesky decomposition
We discuss how the Cholesky decomposition may be used to ascertain whether a
critical point of the field theory scalar potential provides a stable vacuum
configuration. We then use this method to derive the stability conditions in a
specific example.Comment: 7 page
Neutrino-induced lepton flavor violation in gauge-mediated supersymmetry breaking
Gauge-mediated supersymmetry breaking is known to greatly suppress flavor
changing neutral current effects. However, we show that gauge mediation in the
context of leptogenesis implies potentially large lepton flavor violating
signals. If the heavy right-handed neutrinos that participate in leptogenesis
are lighter than the messenger scale of gauge mediation, they will induce
flavor off-diagonal masses to the sleptons which in turn can induce large
effects in mu to e gamma, tau to mu gamma, and mu-e conversion in nuclei. We
demonstrate this result and compute numerically the lepton-flavor violating
decay and conversion rates in scenarios of direct gauge mediation.Comment: 18 pages, 5 figure
Dibaryon Spectroscopy
The AdS/CFT correspondence relates dibaryons in superconformal gauge theories
to holomorphic curves in Kaehler-Einstein surfaces. The degree of the
holomorphic curves is proportional to the gauge theory conformal dimension of
the dibaryons. Moreover, the number of holomorphic curves should match, in an
appropriately defined sense, the number of dibaryons. Using AdS/CFT backgrounds
built from the generalized conifolds of Gubser, Shatashvili, and Nekrasov
(1999), we show that the gauge theory prediction for the dimension of
dibaryonic operators does indeed match the degree of the corresponding
holomorphic curves. For AdS/CFT backgrounds built from cones over del Pezzo
surfaces, we are able to match the degree of the curves to the conformal
dimension of dibaryons for the n'th del Pezzo surface, n=1,2,...,6. Also, for
the del Pezzos and the A_k type generalized conifolds, for the dibaryons of
smallest conformal dimension, we are able to match the number of holomorphic
curves with the number of possible dibaryon operators from gauge theory.Comment: 30 pages, 6 figures, corrected refs; v3 typos correcte
Mars Aeronomy Observer: Report of the Science Working Team
The Mars Aeronomy Observer (MAO) is a candidate follow-on mission to Mars Observer (MO) in the Planetary Observer Program. The four Mariner and two Viking spacecraft sent to Mars between 1965 and 1976 have provided a wealth of information concerning Martian planetology. The Mars Observer, to be launched in 1990, will build on their results by further examining the elemental and mineralogical composition of the surface, the strength and multipolar composition of the planetary magnetic field, the gravitational field and topography, and the circulation of the lower atmosphere. The Mars Aeronomy Observer is intended to address the last major aspects of Martian environment which have yet to be investigated: the upper atmosphere, the ionsphere, and the solar wind interaction region
Obstructions to the Existence of Sasaki-Einstein Metrics
We describe two simple obstructions to the existence of Ricci-flat Kahler
cone metrics on isolated Gorenstein singularities or, equivalently, to the
existence of Sasaki-Einstein metrics on the links of these singularities. In
particular, this also leads to new obstructions for Kahler-Einstein metrics on
Fano orbifolds. We present several families of hypersurface singularities that
are obstructed, including 3-fold and 4-fold singularities of ADE type that have
been studied previously in the physics literature. We show that the AdS/CFT
dual of one obstruction is that the R-charge of a gauge invariant chiral
primary operator violates the unitarity bound.Comment: 35 pages, 1 figure; references and a footnote adde
Condensate cosmology in O'Raifeartaigh models
Flat directions charged under an R-symmetry are a generic feature of
O'Raifeartaigh models. Non-topological solitons associated with this symmetry,
R-balls, are likely to form through the fragmentation of a condensate, itself
created by soft terms induced during inflation. In gravity mediated SUSY
breaking R-balls decay to gravitinos, reheating the universe. For gauge
mediation R-balls can provide a good dark matter candidate. Alternatively they
can decay, either reheating or cooling the universe. Conserved R-symmetry
permits decay to gravitinos or gauginos, whereas spontaneously broken
R-symmetry results in decay to visible sector gauge bosons.Comment: 29 pages, 5 figures. Comments and references added, accepted for
publication in JHE
SQCD: A Geometric Apercu
We take new algebraic and geometric perspectives on the old subject of SQCD.
We count chiral gauge invariant operators using generating functions, or
Hilbert series, derived from the plethystic programme and the Molien-Weyl
formula. Using the character expansion technique, we also see how the global
symmetries are encoded in the generating functions. Equipped with these methods
and techniques of algorithmic algebraic geometry, we obtain the character
expansions for theories with arbitrary numbers of colours and flavours.
Moreover, computational algebraic geometry allows us to systematically study
the classical vacuum moduli space of SQCD and investigate such structures as
its irreducible components, degree and syzygies. We find the vacuum manifolds
of SQCD to be affine Calabi-Yau cones over weighted projective varieties.Comment: 49 pages, 1 figur