2,017 research outputs found
Kaon Weak Decays in Chiral Theories
The ten nonleptonic weak decays , , , , , are predicted for a
chiral pole model based on the linear sigma model theory which automatically
satisfies the partial conservation of axial current (PCAC) hypothesis. These
predictions, agreeing with data to the 5% level and containing no or at most
one free parameter, are compared with the results of chiral perturbation theory
(ChPT). The latter ChPT approach to one-loop level is known to contain at least
four free parameters and then predicts a rate
which is 60% shy of the experimental value. This suggests that ChPT is an
unsatisfactory approach towards predicting kaon weak decays.Comment: 12 pages, 8 eps figure
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Supporting reflection and creative thinking by carers of older people with dementia
This vision paper frames requirements engineering as a creative problem solving process. Its purpose is to enable requirements researchers and practitioners to recruit relevant theories, models, techniques and tools from creative problem solving to understand and support requirements processes more effectively. It uses 4 drivers to motivate the case for requirements engineering as a creative problem solving process. It then maps established requirements activities onto one of the longest-established creative problem solving processes, and uses these mappings to locate opportunities for the application of creative problem solving in requirements engineering. The second half of the paper describes selected creativity theories, techniques, software tools and training that can be adopted to improve requirements engineering research and practice. The focus is on support for problem and idea finding - two creative problem solving processes that our investigation revealed are poorly supported in requirements engineering. The paper ends with a research agenda to incorporate creative processes, techniques, training and tools in requirements projects
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Introducing creativity techniques and software apps to the care of people with dementia
This poster reports research to introduce creative problem solving techniques and software to the care for people with dementia in residential homes
The discontinuous Galerkin method for fractional degenerate convection-diffusion equations
We propose and study discontinuous Galerkin methods for strongly degenerate
convection-diffusion equations perturbed by a fractional diffusion (L\'evy)
operator. We prove various stability estimates along with convergence results
toward properly defined (entropy) solutions of linear and nonlinear equations.
Finally, the qualitative behavior of solutions of such equations are
illustrated through numerical experiments
H¹-PERTURBATIONS OF SMOOTH SOLUTIONS FOR A WEAKLY DISSIPATIVE HYPERELASTIC-ROD WAVE EQUATION
We consider a weakly dissipative hyperelastic-rod wave equation (or weakly dissipative Camassa-Holm equation) describing nonlinear dispersive dissipative waves in compressible hyperelastic rods. By fixed a smooth solution, we establish the existence of a strongly continuous semigroup of global weak solutions for any initial perturbation from . In particular, the supersonic solitary shock waves [8] are included in the analysis
Consistently computing the K -> pi long distance weak transition
First we extract the long-distance (LD) weak matrix element from certain data
and give compatible theoretical estimates. We also link this LD scale to the
single-quark-line (SQL) transition scale and then test the latter SQL scale
against the decuplet weak decay amplitude ratio. Finally, we study LD decay.
All of these experimental and theoretical values are in good agreement. We
deduce an average value from eleven experimental determinations compared to the
theoretical SQL values average.Comment: 19 pages, 9 figures minor change to the Conclusions and abstract
sectio
NUMERICAL SCHEMES FOR COMPUTING DISCONTINUOUS SOLUTIONS OF THE DEGASPERIS-PROCESI EQUATION
Recent work [4] has shown that the Degasperis-Procesi equation is well-posed in the class of (discontinuous) entropy solutions. In the present paper we construct numerical schemes and prove that they converge to entropy solutions. Additionally, we provide several numerical examples accentuating that discontinuous (shock) solutions form independently of the smoothness of the initial data. Our focus on discontinuous solutions contrasts notably with the existing literature on the Degasperis-Procesi equation, which seems to emphasize similarities with the Camassa-Holm equation (bi-Hamiltonian structure, integrabillity, peakon solutions, H1 as the relevant functional space)
Polynomial Cointegration among Stationary Processes with Long Memory
n this paper we consider polynomial cointegrating relationships among
stationary processes with long range dependence. We express the regression
functions in terms of Hermite polynomials and we consider a form of spectral
regression around frequency zero. For these estimates, we establish consistency
by means of a more general result on continuously averaged estimates of the
spectral density matrix at frequency zeroComment: 25 pages, 7 figures. Submitted in August 200
Løgstrup's Criticism of Kierkegaard - Epistemological and Anthropological Dimensions
Løgstrup's Criticism of Kierkegaard - Epistemological and Anthropological Dimension
Remarks on the f_0(400-1200) scalar meson as the dynamically generated chiral partner of the pion
The quark-level linear sigma model is revisited, in particular concerning the
identification of the f_0(400-1200) (or \sigma(600)) scalar meson as the chiral
partner of the pion. We demonstrate the predictive power of the linear sigma
model through the pi-pi and pi-N s-wave scattering lengths, as well as several
electromagnetic, weak, and strong decays of pseudoscalar and vector mesons. The
ease with which the data for these observables are reproduced in the linear
sigma model lends credit to the necessity to include the sigma as a fundamental
q\bar{q} degree of freedom, to be contrasted with approaches like chiral
perturbation theory or the confining NJL model of Shakin and Wang.Comment: 15 pages, plain LaTeX, 3 EPS figure
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