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We calculate the BK parameter within the framework of the 1/Nc expansion. We essentially use the technique presented by Bardeen, Buras and Gérard but calculate an off-shell Green function in order to disentangle different contributions. We study this Green function in pure Chiral Perturbation Theory (CHPT) first and afterwards in the 1/Nc expansion in the presence of an explicit cut-off to determi
Introduction: Massive bleeding is a serious complication associated with impaired survival after surgery for acute type A aortic dissection (ATAAD). There are no previous reports evaluating the effect of ATAAD and associated surgery on von Willebrand factor (VWF). The aim of the present study was to analyze VWF activity (VWF:GPIbM) and thus the potential of Factor (F) VIII/VWF concentrate as a tre
We present a calculation of the electromagnetic π+-π0 mass difference within the framework of the QCD effective action approach. The dependence on the constituent chiral quark mass is discussed.
We have calculated the next to leading corrections to the processes γπ- → π0π- and η → π+π-γ in chiral perturbation theory. The loop diagrams are divergent, requiring the contributions from the O(p6) lagrangian. The finite parts of the coefficients of the O(p6) terms are calculated assuming their saturation by the vector meson contribution. These corrections improve the agreement between the theor
We discuss the extended Nambu-Jona-Lasinio model as a low energy expansion, all two-point functions and an example of a three-point function to all orders in momenta and quark masses. The model is treated at leading level in 1/Nc but otherwise exact. Some comments about the QCD flavour anomaly and Vector Meson Dominance in this class of models is made.
Background: Measures of overall gait deviations such as the Gait Profile Score (GPS) and the Gait Variable Score (GVS) are used to evaluate gait in clinical practice and for research purposes. In the clinical setting, gait deviations are often visually assessed and classified using structured protocols such as the Clubfoot Assessment Protocol (CAP). Research question: Determine the relationship b
A general expression containing all the divergences in Chiral Perturbation Theory at one loop for anomalous processes has been calculated. The nonrenormalization of some amplitudes (Adler-Bardeen theorem) is observed. The different types of corrections are identified. The contributions from vector meson exchange are determined for all anomalous processes. Explicit cancellation of divergences is sh
We present a calculation of the hadronic light-by-light contributions to the muon g-2 in the 1/Nc expansion. We have used an extended Nambu-Jona-Lansinio model and introduced an explicit cutoff for the high energy region. We then have critically studied the relative size of the high energy contributions. Although we find them large, we can give an estimate of the light-by-light contribution to aμ
Using two different methods inspired by duality transformations we present the equivalence between effective Lagrangians for massive vector mesons using a vector field and an antisymmetric tensor field. This completes the list of explicit field transformations between the various effective Lagrangian methods to describe massive vector and axial vector mesons. Our method automatically generates the
We use the 1/Nc method to estimate electromagnetic contributions to vector meson masses and mixings. We identify several new sources of ρ - ω mixing coming from short-distance effects. We comment on the extraction of quark masses from the vector meson masses. We also present a simple group theoretical discussion of the electromagnetic mass differences.
We estimate the 0 electromagnetic mass difference within the 1/N expansion approach to hadronic matrix elements. Perturbative QCD and a truncated meson theory describe the high- and low-photon-loop-momentum contributions, respectively. The matching between these complementary pictures for strong interactions is discussed.
According to Swärd (2012, p. 36), poverty has “many faces and its appearance is dependent upon time, place and type of society, ideological ideas and values”. The aim of this article was to study the beliefs about poverty held by Swedish students of social work, nursing and pre-school teaching. The study employed the experimental factorial survey vignette method, involving the use of fictitious de
As a part of the greening of the EU's Common Agricultural Policy in 2013, Ecological Focus Areas (EFA) became mandatory for many European farmers, with the aim to enhance on-farm biodiversity. However, their effects on biodiversity have been disputed. In this interdisciplinary effort, we assessed the effects of current and alternative formulations of EFA regulations in Sweden. By complementing eco
Syftet med artikeln är att introducera och demonstrera ett pedagogiskt verktyg baserat på användningen av fiktiva fall (vinjetter) konstruerade enligt den experimentella faktoriella surveymetodens principer. Dessa vinjetter är – till skillnad från traditionella ”case” eller ”fallbeskrivningar” – helt igenom kvantitativa, i betydelsen att de kan analyseras i termer av ett antal variabler (dimension
