1,876 research outputs found
Ice: a strongly correlated proton system
We discuss the problem of proton motion in Hydrogen bond materials with
special focus on ice. We show that phenomenological models proposed in the past
for the study of ice can be recast in terms of microscopic models in close
relationship to the ones used to study the physics of Mott-Hubbard insulators.
We discuss the physics of the paramagnetic phase of ice at 1/4 filling (neutral
ice) and its mapping to a transverse field Ising model and also to a gauge
theory in two and three dimensions. We show that H3O+ and HO- ions can be
either in a confined or deconfined phase. We obtain the phase diagram of the
problem as a function of temperature T and proton hopping energy t and find
that there are two phases: an ordered insulating phase which results from an
order-by-disorder mechanism induced by quantum fluctuations, and a disordered
incoherent metallic phase (or plasma). We also discuss the problem of
decoherence in the proton motion introduced by the lattice vibrations (phonons)
and its effect on the phase diagram. Finally, we suggest that the transition
from ice-Ih to ice-XI observed experimentally in doped ice is the
confining-deconfining transition of our phase diagram.Comment: 12 pages, 9 figure
Interference Effects, Time Reversal Violation and Search for New Physics in Hadronic Weak Decays
We propose some methods for studying hadronic sequential two-body decays
involving more spinning particles. It relies on the analysis of T-odd and
T-even asymmetries, which are related to interference terms. The latter
asymmetries turn out to be as useful as the former ones in inferring time
reversal violating observables; these in turn may be sensitive, under some
particular conditions, to possible contributions beyond the standard model. Our
main result is that one can extract such observables even after integrating the
differential decay width over almost all of the available angles. Moreover we
find that the correlations based exclusively on momenta are quite general,
since they provide as much information as those involving one or more spins. We
generalize some methods already proposed in the literature for particular decay
channels, but we also pick out a new kind of time reversal violating
observables. Our analysis could be applied, for example, to data of LHCb
experiment.Comment: 35 page
`In pursuit of the Nazi mind?' the deployment of psychoanalysis in the allied struggle against Germany
This paper discusses how psychoanalytic ideas were brought to bear in the Allied struggle against the Third Reich and explores some of the claims that were made about this endeavour. It shows how a variety of studies of Fascist psychopathology, centred on the concept of superego, were mobilized in military intelligence, post-war planning and policy recommendations for ‘denazification’. Freud's ideas were sometimes championed by particular army doctors and government planners; at other times they were combined with, or displaced by, competing, psychiatric and psychological forms of treatment and diverse studies of the Fascist ‘personality’. This is illustrated through a discussion of the treatment and interpretation of the deputy leader of the Nazi Party, Rudolf Hess, after his arrival in Britain in 1941
Effect of intragastric acid stability of fat emulsions on gastric emptying, plasma lipid profile and postpradial satiety
Fat is often included in common foods as an emulsion of dispersed oil droplets to enhance the organoleptic quality and stability. The intragastric acid stability of emulsified fat may impact on gastric emptying, satiety and plasma lipid absorption. The aim of the present study was to investigate whether, compared with an acid-unstable emulsion, an acid-stable fat emulsion would empty from the stomach more slowly, cause more rapid plasma lipid absorption and cause greater satiety. Eleven healthy male volunteers received on two separate occasions 500 ml of 15% (w/w) [13C]palmitate-enriched olive oil-in-water emulsion meals which were either stable or unstable in the acid gastric environment. MRI was used to measure gastric emptying and the intragastric oil fraction of the meals. Blood sampling was used to measure plasma lipids and visual analogue scales were used to assess satiety. The acid-unstable fat emulsion broke and rapidly layered in the stomach. Gastric emptying of meal volume was slower for the acid-stable fat emulsion (P,0·0001; two-way ANOVA). The rate of energy delivery of fat from the stomach to the duodenum was not different up to t ¼ 110 min. The acid-stable emulsion induced increased fullness (P,0·05), decreased hunger (P,0·0002), decreased appetite (P,0·0001) and increased the concentration of palmitic acid tracer in the chylomicron fraction (P,0·04). This shows that it is possible to delay gastric emptying and increase satiety by stabilising the intragastric distribution of fat emulsions against the gastric acid environment. This could have implications for the design of novel foods
Momentum asymmetries as CP violating observables
Three body decays can exhibit CP violation that arises from interfering
diagrams with different orderings of the final state particles. We construct
several momentum asymmetry observables that are accessible in a hadron collider
environment where some of the final state particles are not reconstructed and
not all the kinematic information can be extracted. We discuss the
complications that arise from the different possible production mechanisms of
the decaying particle. Examples involving heavy neutralino decays in
supersymmetric theories and heavy Majorana neutrino decays in Type-I seesaw
models are examined.Comment: 20 pages, 9 figures. Clarifying comments and one reference added,
matches published versio
Phase transitions in two dimensions - the case of Sn adsorbed on Ge(111) surfaces
Accurate atomic coordinates of the room-temperature (root3xroot3)R30degree
and low-temperature (3x3) phases of 1/3 ML Sn on Ge(111) have been established
by grazing-incidence x-ray diffraction with synchrotron radiation. The Sn atoms
are located solely at T4-sites in the (root3xroot3)R30degree structure. In the
low temperature phase one of the three Sn atoms per (3x3) unit cell is
displaced outwards by 0.26 +/- 0.04 A relative to the other two. This
displacement is accompanied by an increase in the first to second double-layer
spacing in the Ge substrate.Comment: RevTeX, 5 pages including 2 figure
CP Phases in Correlated Production and Decay of Neutralinos in the Minimal Supersymmetric Standard Model
We investigate the associated production of neutralinos
accompanied by the neutralino
leptonic decay , taking into
account initial beam polarization and production-decay spin correlations in the
minimal supersymmetric standard model with general CP phases but without
generational mixing in the slepton sector. The stringent constraints from the
electron EDM on the CP phases are also included in the discussion. Initial beam
polarizations lead to three CP--even distributions and one CP--odd
distribution, which can be studied independently of the details of the
neutralino decays. We find that the production cross section and the branching
fractions of the leptonic neutralino decays are very sensitive to the CP
phases. In addition, the production--decay spin correlations lead to several
CP--even observables such as lepton invariant mass distribution, and lepton
angular distribution, and one interesting T--odd (CP--odd) triple product of
the initial electron momentum and two final lepton momenta, the size of which
might be large enough to be measured at the high--luminosity future
electron--positron collider or can play a complementary role in constraining
the CP phases with the EDM constraints.Comment: Revtex, 37 pages, 12 eps figure
Continuum Surface Energy from a Lattice Model
We investigate connections between the continuum and atomistic descriptions
of deformable crystals, using certain interesting results from number theory.
The energy of a deformed crystal is calculated in the context of a lattice
model with general binary interactions in two dimensions. A new bond counting
approach is used, which reduces the problem to the lattice point problem of
number theory. The main contribution is an explicit formula for the surface
energy density as a function of the deformation gradient and boundary normal.
The result is valid for a large class of domains, including faceted (polygonal)
shapes and regions with piecewise smooth boundaries.Comment: V. 1: 10 pages, no fig's. V 2: 23 pages, no figures. Misprints
corrected. Section 3 added, (new results). Intro expanded, refs added.V 3: 26
pages. Abstract changed. Section 2 split into 2. Section (4) added material.
V 4, 28 pages, Intro rewritten. Changes in Sec.5 (presentation only). Refs
added.V 5,intro changed V.6 address reviewer's comment
Critical animal and media studies: Expanding the understanding of oppression in communication research
Critical and communication studies have traditionally neglected the oppression conducted by humans towards other animals. However, our (mis)treatment of other animals is the result of public consent supported by a morally speciesist-anthropocentric system of values. Speciesism or anthroparchy, as much as any other mainstream ideologies, feeds the media and at the same time is perpetuated by them. The goal of this article is to remedy this neglect by introducing the subdiscipline of Critical Animal and Media Studies. Critical Animal and Media Studies takes inspiration both from critical animal studies – which is so far the most consolidated critical field of research in the social sciences addressing our exploitation of other animals – and from the normative-moral stance rooted in the cornerstones of traditional critical media studies. The authors argue that the Critical Animal and Media Studies approach is an unavoidable step forward for critical media and communication studies to engage with the expanded circle of concerns of contemporary ethical thinking
Toward High Precision Higgs-Boson Measurements at the International Linear e+e- Collider
This report reviews the properties of Higgs bosons in the Standard Model (SM)
and its various extensions. We give an extensive overview about the potential
of the ILC operated at centre-of-mass energies up to 1 TeV (including the gamma
gamma option) for the determination of the Higgs boson properties. This
comprises the measurement of the Higgs boson mass, its couplings to SM fermions
and gauge bosons, and the determination of the spin and the CP quantum numbers
of the Higgs. The extensions of the SM that are analyzed in more detail are
heavy SM-like Higgs bosons, heavy Higgs bosons in the framework of
Supersymmetry (SUSY) and further exotic scenarios. We review recent theoretical
developments in the field of Higgs boson physics. The important question what
the ILC can contribute to Higgs boson physics after the LHC, the LHC/ILC
interplay and synergy is discussed. The impact of Higgs boson physics on
cosmology in several SUSY frameworks is analyzed. The impact of the accelerator
and dector performance on the precision of measurements are discussed in
detail. We propose a strategy to optimize future analyses. Open questions
arising for the various topics are listed, further topics of study and
corresponding roadmaps are suggested.Comment: 128 pages, lots of figures. One subsection added and other minor
modification
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