Covariant Spectator Theory and Hadron Structure

We present the first results of a study on meson spectroscopy using a covariant formalism based on the Covariant Spectator Theory. Our approach is derived directly in Minkowski space and it approximates the Bethe–Salpeter equation by taking effectively into account the contributions from both ladder and crossed ladder diagrams in the $q\bar{q}$ interaction kernel. A general Lorentz structure of the kernel is tested and chiral constraints on the kernel are discussed. Results for the pion form factor are also presented.

Covariant Spectator Theory of heavy–light and heavy mesons and the predictive power of covariant interaction kernels

The Covariant Spectator Theory (CST) is used to calculate the mass spectrum and vertex functions of heavy–light and heavy mesons in Minkowski space. The covariant kernel contains Lorentz scalar, pseudoscalar, and vector contributions. The numerical calculations are performed in momentum space, where special care is taken to treat the strong singularities present in the confining kernel. The observed meson spectrum is very well reproduced after fitting a small number of model parameters. Remarkably, a fit to a few pseudoscalar meson states only, which are insensitive to spin–orbit and tensor forces and do not allow to separate the spin–spin from the central interaction, leads to essentially the same model parameters as a more general fit. This demonstrates that the covariance of the chosen interaction kernel is responsible for the very accurate prediction of the spin-dependent quark–antiquark interactions.

Quark model with chiral-symmetry breaking and confinement in the Covariant Spectator Theory

We propose a model for the quark-antiquark interaction in Minkowski space using the Covariant Spectator Theory. We show that with an equal-weighted scalar-pseudoscalar structure for the confining part of our interaction kernel the axial-vector Ward-Takahashi identity is preserved and our model complies with the Adler-zero constraint for π-π-scattering imposed by chiral symmetry.

Chiral-symmetry Breaking and Pion Structure in the Covariant Spectator Theory

We introduce a covariant approach in Minkowski space for the description of quarks and mesons that exhibits both chiral-symmetry breaking and confinement. In a simple model for the interquark interaction, the quark mass function is obtained and used in the calculation of the pion form factor. We study the effects of the mass function and the different quark pole contributions on the pion form factor.

Imaginar metáforas de amor, sexo e fé: uma leitura literária de Breaking the Waves (1996) de Lars von Trier

Either with words or images, the expression of feelings results, in a work of art, in communication. If this was not the case, the work would not require a spectator or a reader. And if words suggest images from what its author refers to and a countless number of figurations may happen, the images from a film reveal what you can see. We are often left with "just" the space for those facts to shape up as possible meanings to which we react with emotion or with a particular intellectualization, finding exactly what we call readings or interpretations. Starting from a definition of literature that we see spilled in the work prospected from the polysystem theory by Itamar Even-Zohar from the Porter Institute for Poetics and Semiotics (University of Tel-Aviv), we consider the dynamic character of every cultural moment/object. This is how a literary reading, that is to apply some of the methodologies in the interpretation of a literary work, is allowed to extend to other cultural objects. This is what we are going to do with Lars von Trier's Breaking the Waves, a landmark in cinema for what the movement and manifest Dogma 95 represents, but that for a literature reader particularly focused on the narration of love in its different manifestations - in which sex and faith are included - a corpus is revealed, filled with interpretative possibilities and emotional reactions, important condiments particularly to the spectator and/or interested reader.

Quarkonia and heavy-light mesons in a covariant quark model

Preliminary calculations using the Covariant Spectator Theory (CST) employed a scalar linear confining interaction and an additional constant vector potential to compute the mesonic mass spectra. In this work we generalize the confining interaction to include more general structures, in particular a vector and also a pseudoscalar part, as suggested by a recent study. A one-gluon-exchange kernel is also implemented to describe the short-range part of the interaction. We solve the simplest CST approxima- tion to the complete Bethe-Salpeter equation, the one-channel spectator equation, using a numerical technique that eliminates all singularities from the kernel. The parameters of the model are determined through a fit to the experimental pseudoscalar meson spectra, with a good agreement for both quarkonia and heavy-light states.

Heavy-Light Mesons in Minkowski Space

Following up on earlier work on the $q\bar{q}$-bound-state problem using a covariant, chiral-symmetric formalism based upon the Covariant Spectator Theory, we study the heavy–light case for both pseudoscalar and vector mesons. Derived directly in Minkowski space, our approach approximates the full Bethe–Salpeter-equation, taking into account, effectively, the contributions of both ladder and crossed ladder diagrams in the kernel. Results for several mass spectra using a relativistic covariant generalization of a Cornell plus a constant potential to model the interquark interaction are given and discussed.

‘Crows’ vs. ‘Avatar’, or: 3D vs. total-dimensional immersion

3D film’s explicit new space depth arguably provides both an enhanced realistic quality to the image and a wealth of more acute visual and haptic sensations (a ‘montage of attractions’) to the increasingly involved spectator. But David Cronenberg’s related ironic remark that ‘cinema as such is from the outset a «special effect»’ should warn us against the geometrical naiveté of such assumptions, within a Cartesian ocularcentric tradition for long overcome by Merleau-Ponty’s embodiment of perception and Deleuze’s notion of the self-consistency of the artistic sensation and space. Indeed, ‘2D’ traditional cinema already provides the accomplished «fourth wall effect», enclosing the beholder behind his back within a space that no longer belongs to the screen (nor to ‘reality’) as such, and therefore is no longer ‘illusorily’ two-dimensional. This kind of totally absorbing, ‘dream-like’ space, metaphorical for both painting and cinema, is illustrated by the episode ‘Crows’ in Kurosawa’s Dreams. Such a space requires the actual effacement of the empirical status of spectator, screen and film as separate dimensions, and it is precisely the 3D caracteristic unfolding of merely frontal space layers (and film events) out of the screen towards us (and sometimes above the heads of the spectators before us) that reinstalls at the core of the film-viewing phenomenon a regressive struggle with reality and with different degrees of realism, originally overcome by film since the Lumière’s Arrival of a Train at Ciotat seminal demonstration. Through an analysis of crucial aspects in Avatar and the recent Cave of Forgotten Dreams, both dealing with historical and ontological deepening processes of ‘going inside’, we shall try to show how the formal and technically advanced component of those 3D-depth films impairs, on the contrary, their apparent conceptual purpose on the level of contents, and we will assume, drawing on Merleau-Ponty and Deleuze, that this technological mistake is due to a lack of recognition of the nature of perception and sensation in relation to space and human experience.

The Worldhood of the Cinematic Image

A close analysis of the specifically cinematographic procedure in Akira Kurosawa’s ‘Dream’ Crows reveals it as an articulated and insightful philosophical statement, endowed with general relevance concerning ‘natural’ perception, phenomenological Erlebnis, mechanical image and aesthetic rapture. The antagonism between the Benjaminian lineage of a mechanical irreducibility of the cinematic image to anthropocentric categories, and the Cartesian tradition of a film-philosophy still relying on the equally irreducible structure of the intentional act, be it the one of a deeply embodied and enworlded counsciousness, in accounting for the essential structure of film and spectator (and their relation), i.e., the antagonism between the decentering primacy of the image and the self-centered primacy of perception, cannot be settled through a simple Phenomenological shift from occularcentric, intentional counsciousness to its embodyment ‘in-the-world’ as yet another carrier of intentionality. Still it remains to be explained what is it in the mechanical image that is able to so deeply affect the human flesh, and conversely, to what features in the human bodily experience is its mechanical other, the fascinating image, so successfuly adressing? It should be expected from the anti-Cartesianism of both the early and the late Merleau-Ponty the textual support for an approach to the essential condition of passivity in movie watching, that would be convergent with Benjamin. The Chapter ‘Le sentir’, in Phénoménologie de la perception, will offer us the proper guide to elucidate what we are already perceiving and conceiving in Kurosawa’s film, where the ex-static phenomenological body of the aesthetical contemplator ‘enters the frame’ like the Benjaminian surgeon enters the body and like the painter - and always already like our deepest level of ‘sensing’, previously to any act of cousciousness - ‘just looses himself in the scene before him’. The Polichinello secret of cinema watching is nonetheless too evident to be seen, and that is where Phenomenological description and reduction are still required.