99 research outputs found
The properties of the three-nucleon system with the dressed-bag model for nn interaction. I: New scalar three-body force
A multi-component formalism is developed to describe three-body systems with
nonstatic pairwise interactions and non-nucleonic degrees of freedom. The
dressed-bag model for interaction based on the formation of an
intermediate six-quark bag dressed by a -field is applied to the
system, where it results in a new three-body force between the six-quark bag
and a third nucleon. Concise variational calculations of bound states are
carried out in the dressed-bag model including the new three-body force. It is
shown that this three-body force gives at least half the total binding
energy, while the weight of non-nucleonic components in the H and He
wavefunctions can exceed 10%. The new force model provides a very good
description of bound states with a reasonable magnitude of the
coupling constant. The model can serve as a natural bridge between dynamical
description of few-nucleon systems and the very successful Walecka approach to
heavy nuclei and nuclear matter.Comment: 26 pages, Latex, 7 figure
Spin 1 inversion: a Majorana tensor force for deuteron alpha scattering
We demonstrate, for the first time, successful S-matrix to potential
inversion for spin one projectiles with non-diagonal yielding a
interaction. The method is a generalization of the
iterative-perturbative, IP, method. We present a test case indicating the
degree of uniqueness of the potential. The method is adapted, using established
procedures, into direct observable to potential inversion, fitting ,
, , and for d + alpha scattering over
a range of energies near 10 MeV. The interaction which we find is
very different from that proposed elsewhere, both real and imaginary parts
being very different for odd and even parity channels.Comment: 7 pages Revtex, 4 ps figure
Harnessing History: Narratives, Identity and Perceptions of Russia's Post-Soviet Role
Russian political elites have long been aware of the power of myths to forge national unity. However, the past six or seven years have seen core myths increasingly situated within a highly selective narrative of Russian history. This narrative is accepted as contextual information for policy discussion, and so sets cognitive parameters for evaluations of Russia's history, identity and role. This standard narrative of Russian history prioritises the state, supports gradualism and continuity, and dramatically reduces the potential for reâconceptualising Russia's role in contemporary international relations
Nothing Is True? The Credibility of News and Conflicting Narratives during âInformation Warâ in Ukraine
In international politics, the strategic narratives of different governments compete for public attention and support. The Russian governmentâs narrative has prompted western concern due to fears that it exerts a destabilizing effect on societies in Eastern Europe and elsewhere. However, the behavior and thought processes of news consumers targeted by contradictory strategic narratives are rarely subjected to analysis. This paper examines how Ukrainian news consumers decide where to get their news and what to believe in a media environment where âpropagandaâ and âdisinformationâ are regarded as major threats to national security. Evidence comes from thirty audio-diaries and in-depth interviews conducted in 2016 among adult residents of Odesa Region. Through qualitative analysis of the diary and interview transcripts, the paper reveals how participants judged the credibility of news and narratives based on their priorities (what they considered important), not just âfactsâ (what they believed had happened). The attribution of importance to different foreign policy issues was associated, in turn, with varying personal experiences, memories, and individual cross-border relationships
Improved +He potentials by inversion, the tensor force and validity of the double folding model
Improved potential solutions are presented for the inverse scattering problem
for +He data. The input for the inversions includes both the data of
recent phase shift analyses and phase shifts from RGM coupled-channel
calculations based on the NN Minnesota force. The combined calculations provide
a more reliable estimate of the odd-even splitting of the potentials than
previously found, suggesting a rather moderate role for this splitting in
deuteron-nucleus scattering generally. The approximate parity-independence of
the deuteron optical potentials is shown to arise from the nontrivial
interference between antisymmetrization and channel coupling to the deuteron
breakup channels. A further comparison of the empirical potentials established
here and the double folding potential derived from the M3Y effective NN force
(with the appropriate normalisation factor) reveals strong similarities. This
result supports the application of the double folding model, combined with a
small Majorana component, to the description even of such a loosely bound
projectile as the deuteron. In turn, support is given for the application of
iterative-perturbative inversion in combination with the double folding model
to study fine details of the nucleus-nucleus potential. A -He tensor
potential is also derived to reproduce correctly the negative Li quadrupole
moment and the D-state asymptotic constant.Comment: 22 pages, 12 figures, in Revte
Moscow-type NN-potentials and three-nucleon bound states
A detailed description of Moscow-type (M-type) potential models for the NN
interaction is given. The microscopic foundation of these models, which appear
as a consequence of the composite quark structure of nucleons, is discussed.
M-type models are shown to arise naturally in a coupled channel approach when
compound or bag-like six-quark states, strongly coupled to the NN channel, are
eliminated from the complete multiquark wave function. The role of the
deep-lying bound states that appear in these models is elucidated. By
introducing additional conditions of orthogonality to these compound six-quark
states, a continuous series of almost on-shell equivalent nonlocal interaction
models, characterized by a strong reduction or full absence of a local
repulsive core (M-type models), is generated. The predictions of these
interaction models for 3N systems are analyzed in detail. It is shown that
M-type models give, under certain conditions, a stronger binding of the 3N
system than the original phase-equivalent model with nodeless wave functions.
An analysis of the 3N system with the new versions of the Moscow NN potential
describing also the higher even partial waves is presented. Large deviations
from conventional NN force models are found for the momentum distribution in
the high momentum region. In particular, the Coulomb displacement energy for
nuclei ^3He - ^3H displays a promising agreement with experiment when the ^3H
binding energy is extrapolated to the experimental value.Comment: 23 pages Latex, 9 figures, to appear in Phys.Rev.
Techniques of disinformation: constructing and communicating "soft facts" after terrorism
Informed by social media data collected following four terror attacks in the UK in 2017, this article delineates a series of âtechniques of disinformationâ used by different actors to try and influence how the events were publicly defined and understood. By studying the causes and consequences of misleading information following terror attacks, the article contributes empirically to the neglected topic of social reactions to terrorism. It also advances scholarship on the workings of disinforming communications, by focusing on a domain other than political elections, which has been the empirical focus for most studies of disinformation to date. Theoretically, the analysis is framed by drawing an analogy with Gresham Sykes and David Matza's (1957) account of the role of âtechniques of neutralizationâ originally published in the American Sociological Review. The connection being that where they studied deviant behaviour, a similar analytic lens can usefully be applied to disinformation cast as âdeviantâ information
Curing of Plasmid pXO1 from Bacillus anthracis Using Plasmid Incompatibility
The large plasmid pXO1 encoding the anthrax toxin is important for the virulence of Bacillus anthracis. It is essential to cure pXO1 from B. anthracis to evaluate its role in the pathogenesis of anthrax infection. Because conventional methods for curing plasmids (e.g., curing agents or growth at elevated temperatures) can induce mutations in the host chromosomal DNA, we developed a specific and reliable method to eliminate pXO1 from B. anthracis using plasmid incompatibility. Three putative replication origins of pXO1 were inserted into a temperature-sensitive plasmid to generate three incompatible plasmids. One of the three plasmids successfully eliminated the large plasmid pXO1 from B. anthracis vaccine strain A16R and wild type strain A16. These findings provided additional information about the replication/partitioning of pXO1 and demonstrated that introducing a small incompatible plasmid can generate plasmid-cured strains of B. anthracis without inducing spontaneous mutations in the host chromosome
Dibaryon model for nuclear force and the properties of the system
The dibaryon model for interaction, which implies the formation of an
intermediate six-quark bag dressed by a -field, is applied to the
system, where it results in a new three-body force of scalar nature between the
six-quark bag and a third nucleon. A new multicomponent formalism is developed
to describe three-body systems with nonstatic pairwise interactions and
non-nucleonic degrees of freedom. Precise variational calculations of
bound states are carried out in the dressed-bag model including the new scalar
three-body force. The unified coupling constants and form factors for and
force operators are used in the present approach, in a sharp contrast to
conventional meson-exchange models. It is shown that this three-body force
gives at least half the total binding energy, while the weight of
non-nucleonic components in the H and He wavefunctions can exceed 10%.
The new force model provides a very good description of bound states with
a reasonable magnitude of the coupling constant. A new Coulomb
force between the third nucleon and dibaryon is found to be very important for
a correct description of the Coulomb energy and r.m.s. charge radius in He.
In view of the new results for Coulomb displacement energy obtained here for
A=3 nuclei, an explanation for the long-term Nolen--Schiffer paradox in nuclear
physics is suggested. The role of the charge-symmetry-breaking effects in the
nuclear force is discussed.Comment: 64 pages, 7 figures, LaTeX, to be published in Phys. At. Nucl. (2005
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