263 research outputs found
Supergravity interacting with bosonic p-branes and local supersymmetry
We study the coupling of supergravity with a purely bosonic brane source
(bosonic p-brane). The interaction, described by the sum of their respective
actions, is self-consistent if the bosonic p-brane is the pure bosonic limit of
a super-p-brane. In that case the dynamical system preserves 1/2 of the local
supersymmetry characteristic of the `free' supergravity.Comment: 11 pages, RevTe
Optical Properties of Heavily Fluorinated Lanthanide Tris β-Diketonate Phosphine Oxide Adducts
The construction of lanthanide(III) chelates that exhibit superior photophysical properties holds great importance in biological and materials science. One strategy to increase the luminescence properties of lanthanide(III) chelates is to hinder competitive non-radiative decay processes through perfluorination of the chelating ligands. Here, the synthesis of two families of heavily fluorinated lanthanide(III) β-diketonate complexes bearing monodentate perfluorinated tris phenyl phosphine oxide ligands have been prepared through a facile one pot reaction [Ln(hfac)3{(ArF)3PO}(H2O)] and [Ln(F7-acac)3{(ArF)3PO}2] (where Ln = Sm3+, Eu3+, Tb3+, Er3+ and Yb3+). Single crystal X-ray diffraction analysis in combination with photophysical studies have been performed to investigate the factors responsible for the differences in the luminescence lifetimes and intrinsic quantum yields of the complexes. Replacement of both bound H2O and C–H oscillators in the ligand backbone has a dramatic effect on the photophysical properties of the complexes, particularly for the near infra-red emitting ion Yb3+, where a five fold increase in luminescence lifetime and quantum yield is observed. The complexes [Sm(hfac)3{(ArF)3PO}(H2O)] (1), [Yb(hfac)3{(ArF)3PO}(H2O)] (5), [Sm(F7-acac)3{(ArF)3PO}2] (6) and [Yb(F7-acac)3{(ArF)3PO}2] (10) exhibit unusually long luminescence lifetimes and attractive intrinsic quantum yields of emission in fluid solution (ΦLn = 3.4% (1); 1.4% (10)) and in the solid state (ΦLn = 8.5% (1); 2.0% (5); 26% (6); 11% (10)), which are amongst the largest values for this class of compounds to date
Fermions in Kaluza-Klein and Randall-Sundrum Theories
The Kaluza-Klein theory and Randall-Sundrum theory are examined
comparatively, with focus on the behavior of the five dimensional (Dirac)
fermion in the dimensional reduction to four dimensions. They are properly
treated using the Cartan formalism. In the KK case, the dual property between
the electric and magnetic dipole moments is revealed in relation to the ratio
of two massive parameters: the inverse of the radius of the extra-space circle
and the 5D fermion mass. The order estimation of the couplings is done. In the
RS case, we consider the interaction with the 5D(bulk) Higgs field and the
gauge field. The chiral property, localization, anomaly phenomena are examined.
We evaluate the bulk quantum effect using the method of the induced effective
action. The electric dipole moment term naturally appears. This is a new origin
of the CP-violation. In the 4D limit, the dual relation between KK model and RS
model appears.Comment: 30 pages, 4 figures, Typographical errors are correcte
Effective action and brane running
We address the renormalized effective action for a Randall-Sundrum brane
running in 5d bulk space. The running behavior of the brane action is obtained
by shifting the brane-position without changing the background and the
fluctuations. After an appropriate renormalization, we obtain an effective, low
energy braneworld action, in which the effective 4d Planck mass is independent
of the running-position. We address some implications of this effective action.Comment: 15 pages, no figur
Gauge-gravity correspondence in de Sitter braneworld
We study the braneworld solutions based on a solvable model of 5d gauged
supergravity with two scalars of conformal dimension three, which correspond to
bilinear operators of fermions in the dual super Yang-Mills
theory on the boundary. An accelerating braneworld solution is obtained when
both scalars are taken as the form of deformations of the super Yang-Mills
theory and the bulk supersymmetry is broken. This solution is smoothly
connected to the Poincare invariant brane in the limit of vanishing
cosmological constant. The stability of this brane-solution and the
correspondence to the gauge theory are addressed.Comment: 16 pages, 1 figur
Holographic dual of the Standard Model on the throat
We apply recent techniques to construct geometries, based on local Calabi-Yau
manifolds, leading to warped throats with 3-form fluxes in string theory, with
interesting structure at their bottom. We provide their holographic dual
description in terms of RG flows for gauge theories with almost conformal
duality cascades and infrared confinement. We describe a model of a throat with
D-branes at its bottom, realizing a 3-family Standard Model like chiral sector.
We provide the explicit holographic dual gauge theory RG flow, and describe the
appearance of the SM degrees of freedom after confinement. As a second
application, we describe throats within throats, namely warped throats with
discontinuous warp factor in different regions of the radial coordinate, and
discuss possible model building applications.Comment: 46 pages, 21 figures, reference adde
Scaling laws in hadronic processes and string theory
We propose a possible scheme for getting the known QCD scaling laws within
string theory. In particular, we consider amplitudes for exclusive scattering
of hadrons at large momentum transfer, hadronic form factors and distribution
functions.Comment: 13 pages, 2 figures, a comment and a reference added, a final version
to appear in Physical Review
Localization of Gravity on Brane Embedded in and
We address the localization of gravity on the Friedmann-Robertson-Walker type
brane embedded in either or bulk space,and derive two
definite limits between which the value of the bulk cosmological constant has
to lie in order to localize the graviton on the brane.The lower limit implies
that the brane should be either or 4d Minkowski in the
bulk.The positive upper limit indicates that the gravity can be trapped also on
curved brane in the bulk space.Some implications to recent
cosmological scenarios are also discussed.Comment: 18 pages, 3 figures, Latex fil
Male frequent attenders of general practice and their help seeking preferences
Background: Low rates of health service usage by men are commonly linked to masculine values and traditional male gender roles. However, not all men conform to these stereotypical notions of masculinity, with some men choosing to attend health services on a frequent basis, for a variety of different reasons. This study draws upon the accounts of male frequent attenders of the General Practitioner's (GP) surgery, examining their help-seeking preferences and their reasons for choosing services within general practice over other sources of support. Methods: The study extends thematic analysis of interview data from the Self Care in Primary Care study (SCinPC), a large scale multi-method evaluation study of a self care programme delivered to frequent attenders of general practice. Data were collected from 34 semi-structured interviews conducted with men prior to their exposure to the intervention. Results: The ages of interviewed men ranged from 16 to 72 years, and 91% of the sample (n= 31) stated that they had a current health condition. The thematic analysis exposed diverse perspectives within male help-seeking preferences and the decision-making behind men's choice of services. The study also draws attention to the large variation in men's knowledge of available health services, particularly alternatives to general practice. Furthermore, the data revealed some men's lack of confidence in existing alternatives to general practice. Conclusions: The study highlights the complex nature of male help-seeking preferences, and provides evidence that there should be no 'one size fits all' approach to male service provision. It also provides impetus for conducting further studies into this under researched area of interest. © 2011 WPMH GmbH
PDF and scale uncertainties of various DY distributions in ADD and RS models at hadron colliders
In the extra dimension models of ADD and RS we study the dependence of the
various parton distribution functions on observable of Drell-Yan process to NLO
in QCD at LHC and Tevatron energies. Uncertainties at LHC due to factorisation
scales in going from leading to next-to-leading order in QCD for the various
distributions get reduced by about 2.75 times for a range . Further uncertainties arising from the error on experimental
data are estimated using the MRST parton distribution functions.Comment: 27 pages, 11 figures, the version to appear in European Physical
Journal
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