Gwunder

This is the written report of a thesis project which was done in the form of a book. This book was produced as a dummy consisting of fifty-five double pages (spreads). The book was planned and executed in all details and it is ready to be printed. The visual part includes a number of photo-sequences: seventy-seven black and white photographs and five postcards. Within these series of images are sequences of seven Swiss poems, seven exerpts from American TV commercials, seven Malay proverbs, seven quotations from the MFA Handbook, passages from seven books dealing with different concepts of photography and seven footnotes. The main theme of the book is the challenge of conventional relationships between reality and its depiction in the photograph. Other themes appearing are visual and literal comments on different processes involved in the whole thesis project, ie. the process of going through the MFA Program, the process of making or taking photographs, the photographic process itself, the process of planning and making the book and the process of looking through the book. The whole project (photographs, texts, the book, the show) was planned to encompass simultaneously everything a photographer could possibly deal with within the given framework

Watson's theorem and electromagnetism in K -> pi pi decay

We consider what constraints unitarity and CPT invariance yield on the strong and electromagnetic phases entering K -> pi pi decay. In particular, we show that the relative size of the electromagnetically-induced changes in the I=0 and I=2 phase shifts in the two--pion final state do not depend on the explicit coupling to the pi^+ pi^- gamma channel. This demonstrates that Watson's theorem can be extended to include the presence of electromagnetism. We point out the consequences for the general structure of the K -> pi pi decay amplitudes in the presence of isospin violation.Comment: 7 pages, LaTeX, axodraw.st

Hadronic eta and eta-prime decays

The hadronic decays eta, eta-prime -> 3 pi and eta-prime -> eta pi pi are investigated within the framework of U(3) chiral effective field theory in combination with a relativistic coupled-channels approach. Final state interactions are included by deriving s- and p-wave interaction kernels for meson-meson scattering from the chiral effective Lagrangian and iterating them in a Bethe-Salpeter equation. Very good overall agreement with currently available data on decay widths and spectral shapes is achieved.Comment: 28 pages, 5 figures, 8 table

Chiral Dynamics and the Low Energy Kaon-Nucleon Interaction

We examine the meson-baryon interaction in the strangeness S=-1 sector using an effective chiral Lagrangian. Potentials are derived from this Lagrangian and used in a coupled-channel calculation of the low energy observables. The potentials are constructed such that in the Born approximation the s-wave scattering amplitude is the same as that given by the effective chiral Lagrangian, up to order $q^2$. Comparison is made with the available low energy hadronic data of the coupled $K^-p, \Sigma \pi, \Lambda \pi$ system, which includes the $\Lambda (1405)$ resonance, $K^-p$ elastic and inelastic scattering, and the threshold branching ratios of the $K^-p$ decay. Good fits to the experimental data and estimates of previously unknown Lagrangian parameters are obtained.Comment: 20 pages, 10 postscript figures, uses revtex, e-mail addresses: [email protected], [email protected], [email protected]

Integrating out the heaviest quark in N--flavour ChPT

We extend a known method to integrate out the strange quark in three flavour chiral perturbation theory to the context of an arbitrary number of flavours. As an application, we present the explicit formulae to one--loop accuracy for the heavy quark mass dependency of the low energy constants after decreasing the number of flavours by one while integrating out the heaviest quark in N--flavour chiral perturbation theory.Comment: 18 pages, 1 figure. Text and references added. To appear in EPJ

Pion-Kaon Scattering near the Threshold in Chiral SU(2) Perturbation Theory

In the context of chiral SU(2) perturbation theory, pion-kaon scattering is analysed near the threshold to fourth chiral order. The scattering amplitude is calculated both in the relativistic framework and by using an approach similar to heavy baryon chiral perturbation theory. Both methods lead to equivalent results. We obtain relations between threshold parameters, valid to fourth chiral order, where all those combinations of low-energy constants which are not associated with chiral-symmetry breaking terms drop out. The remaining low-energy constants can be estimated using chiral SU(3) symmetry. Unfortunately, the experimental information is not precise enough to test our low-energy theorems.Comment: 38 pages, 5 figures, PhD Thesis, references adde

Chiral Lagrangians at finite density

The effective SU(2) chiral Lagrangian with external sources is given in the presence of non-vanishing nucleon densities by calculating the in-medium contributions of the chiral pion-nucleon Lagrangian. As a by product, a relativistic quantum field theory for Fermi many-particle systems at zero temperature is directly derived from relativistic quantum field theory with functional methods.Comment: 6 Pages, 3 figures, REVTeX. Extended version. Explicit Feynman rules are give

Meson Masses in High Density QCD

The low-energy effective theories for the two- and three-flavor color-superconductors arising in the high density limit of QCD are discussed. Using an effective field theory to describe quarks near the fermi surface, we compute the masses of the pseudo-Goldstone bosons that dominate the low-momentum dynamics of these systems.Comment: 13 pages, 3 figures, late

Non-Perturbative Study of the Light Pseudoscalar Masses in Chiral Dynamics

We perform a non-perturbative chiral study of the masses of the lightest pseudoscalar mesons. In the calculation of the self-energies we employ the S-wave meson-meson amplitudes taken from Unitary Chiral Perturbation Theory (UCHPT) that include the lightest nonet of scalar resonances. Values for the bare masses of pions and kaons are obtained, as well as an estimate of the mass of the \eta_8. The former are found to dominate the physical pseudoscalar masses. We then match to the self-energies from Chiral Perturbation Theory (CHPT) to O(p^4), and a robust relation between several O(p^4) CHPT counterterms is obtained. We also resum higher orders from our calculated self-energies. By taking into account values determined from previous chiral phenomenological studies of m_s/\hat{m} and 3L_7+L^r_8, we determine a tighter region of favoured values for the O(p^4) CHPT counterterms 2L^r_6-L^r_4 and 2L^r_8-L^r_5. This determination perfectly overlaps with the recent determinations to O(p^6) in CHPT. We warn about a likely reduction in the value of m_s/\hat{m} by higher loop diagrams and that this is not systematically accounted for by present lattice extrapolations. We also provide a favoured interval of values for m_s/\hat{m} and 3L_7+L^r_8.Comment: 26 pages, 9 figures. Original new material is included. Major rewriting when comparing with lattice QC

Creative Chord Sequence Generation for Electronic Dance Music

This paper describes the theory and implementation of a digital audio workstation plug-in for chord sequence generation. The plug-in is intended to encourage and inspire a composer of electronic dance music to explore loops through chord sequence pattern definition, position locking and generation into unlocked positions. A basic cyclic first-order statistical model is extended with latent diatonicity variables which permits sequences to depart from a specified key. Degrees of diatonicity of generated sequences can be explored and parameters for voicing the sequences can be manipulated. Feedback on the concepts, interface, and usability was given by a small focus group of musicians and music producers.This research was supported by the project I2C8 (Inspiring to Create) which is funded by the European Union's Horizon 2020 Research and Innovation programme under grant agreement number 754401