The nature of antimatter is examined in the context of algebraic quantum field theory. It is shown that the notion of antimatter is more general than that of antiparticles. Properly speaking, then, antimatter is not matter made up of antiparticles—rather, antiparticles are particles made up of antimatter. We go on to discuss whether the notion of antimatter is itself completely general in quantum field theory. Does the matter–antimatter distinction apply to all field theoretic systems? The answer depends on which of (...) several possible criteria we should impose on the space of physical states. (shrink)

So far this has been a lonely and unrewarding quest. New experiments occasionally come along which point to a breakdown of the Standard Model, but up to now they have invariably been proved wrong by more careful analysis or subsequent experiments with better data. A case in point is the energetic jet data from the CDF experiment at FermiLab which suggested possible substructure of the quark. (See my AV column "Inside the Quark" in the September-1996 issue of Analog.) The CDF (...) group found an unexpected excess of "jets" (clumps of energetic particles moving in the same direction) with energies above 200 GeV in their data. They found that they could not explain this excess of high energy jets using the Standard Model, as interpreted by standard theoretical procedures, and they pointed out that the data might represent new physics, possibly an indication that the quark is a composite object made of even more fundamental particles. (shrink)

This column is about recent evidence from the Super Kamiokande detector in Japan indicating that at least one of the three known neutrino flavors, the mu-neutrino, has a non-zero rest mass. To put this result in the proper context, I'll briefly review parts of the standard model of particle physics.

James Elkins has shaped the discussion about how we—as artists, as art historians, or as outsiders—view art. He has not only revolutionized our thinking about the purpose of teaching art, but has also blazed trails in creating a means of communication between scientists, artists, and humanities scholars. In Six Stories from the End of Representation , Elkins weaves stories about recent images from painting, photography, physics, astrophysics, and microscopy. These images, regardless of origin, all fail as representations: they are blurry, (...) dark, pixellated, or otherwise unclear. In these opaque images, Elkins finds an opportunity to create stories that speak simultaneously to artists and to scientists, and to open both those fields to those of us who have little purchase in either. Regarding each image through the lens of the discipline that produced it, Elkins simultaneously affirms the unique structure of each way of viewing the world and brings those views together into a vibrant conversation. (shrink)

Summary Some case studies in elementary particle physics are presented in this work, that can be used for the critical appraisal of specific criteria which were proposed to account for the development of Heisenberg's work. It is attempted to define the philosophical problems associated with and emerging from the structures of theories, rather than analyse the philosophical aspects of concepts used in elementary particle physics. This necessitates the discussion of the relationship between theory and experiment, and the role of the (...) mathematical framework being used. The question of elementarity is studied in this connection. Popper's tetradic schema and his concept of world three are modified, and it is shown that the new schema can accommodate the development of certain research programs in a much more satisfactory manner. As a result of the systematic treatment of specific research programs, the principle of contextual re-interpretation is expanded by specifying the different kinds of interpretations at the various stages of development of theories. It is also shown that principles such as those of simplicity and beauty can be understood in terms of the mathematical structure of the theories, and their methodological importance is emphasized. (shrink)

Die Elementarteilchenphysik gilt weithin als eine Teildisziplin der Physik, die ein reduktionistisches Programm par excellence verfolgt. In dieser Arbeit soll versucht werden, unter Berücksichtigung einer Analyse neuerer Methoden der Elementarteilchenphysik, die Berechtigung dieser Behauptung zu klären. Die Reduktionismusproblemtik läßt sich in ontologische, epistemologische und methodologische Aspekte untergliedern.

This paper responds to a recent claim by Shrader-Frechette that current particle physics, with its essentially atomist paradigm, is in a state of Kuhnian crisis. We respond to Shrader-Frechette's claim in two ways: first, we argue directly against much of the evidence used by Shrader-Frechette as indicators of Kuhnian crisis; second, we question Shrader-Frechette's application of Kuhnian categories to current research in general, pointing out the dangers inherent in such an analysis.

According to structural realism, in mature science there is structural continuity along theoretical change. A major counterexample to this thesis is the transition from the Eightfold Way to the Standard Model in particle physics. Nevertheless, the notion of structure is significantly important in comprehending the theoretical picture of particle physics, where particles change and undergo transmutations, while the only thing which remains unchanged is the basic structure, i.e. the symmetry group which controls the transmutations. This kind of view agrees with (...) the paradigmatic case where the structure is an internal symmetry and the instantiations are the elementary particles. The metaphysical view which reflects this situation is a version of ontic structuralism. (shrink)

In this paper, I address the issue of to what extent the theory-dominated view of scientific experimentation describes scientific practice. I rely on a time period from the history of High Energy Physics (HEP), which spans from early 1960s to early 1970s. I argue that theory-ladenness of experimentation (TLE), which grounds theory-dominated conception of experimentation is too coarse-grained inasmuch as it prevents us from seeing the correct relationship that exists between theorizing and experimenting in the scientific practice of HEP. I (...) articulate that in order to be able to get a better understanding of scientific practice, a revision needs to be made in the general conception of TLE. I propose that such a revision is possible if we abandon the commitment that experimentation is always driven by theory. I consider what I call “theory-drivenness” of experimentation (TDE) as a form of theory-ladenness, which amounts to the claim that experiments, from their initial design up to their final stage, are carried out under the framework of a prevailing theory for the purpose of providing definite answers to specific questions already posed by the same theory. I argue that electron-proton inelastic scattering experiments in HEP were firstly carried out without having any recourse to a phenomenological model. From here, I claim that these experiments are not theory-laden in the sense implied by TDE. On the other hand, I argue, inelastic scattering experiments are theory-laden due to the fact that the scientists who perform them are committed to background theories of HEP. That is, I admit the validity of TLE as a philosophical claim, but I attribute a weaker status to it as opposed to its general conception. That is, I propose to differentiate TDE from TLE by claiming that TLE does not entail TDE. (shrink)

We briefly describe in this paper the passage from Mendeleev’s chemistry (1869) to atomic physics (in the 1900’s), nuclear physics (in 1932) and particle physics (from 1953 to 2006). We show how the consideration of symmetries, largely used in physics since the end of the 1920’s, gave rise to a new format of the periodic table in the 1970’s. More specifically, this paper is concerned with the application of the group SO(4,2)⊗SU(2) to the periodic table of chemical elements. It is (...) shown how the Madelung rule of the atomic shell model can be used to set up a periodic table that can be further rationalized via the group SO(4,2)⊗SU(2) and some of its sub-groups. Qualitative results are obtained from this nonstandard table. (shrink)

The success of particle detection in high energy physics colliders critically depends on the criteria for selecting a small number of interactions from an overwhelming number that occur in the detector. It also depends on the selection of the exact data to be analyzed and the techniques of analysis. The introduction of automation into the detection process has traded the direct involvement of the physicist at each stage of selection and analysis for the efficient handling of vast amounts of data. (...) This tradeoff, in combination with the organizational changes in laboratories of increasing size and complexity, has resulted in automated and semi-automated systems of detection. Various aspects of the semi-automated regime were greatly diminished in more generic automated systems, but turned out to be essential to a number of surprising discoveries of anomalous processes that led to theoretical breakthroughs, notably the establishment of the Standard Model of particle physics. The automated systems are much more efficient in confirming specific hypothesis in narrow energy domains than in performing broad exploratory searches. Thus, in the main, detection processes relying excessively on automation are more likely to miss potential anomalies and impede potential theoretical advances. I suggest that putting substantially more effort into the study of electron–positron colliders and increasing its funding could minimize the likelihood of missing potential anomalies, because detection in such an environment can be handled by the semi-automated regime—unlike detection in hadron colliders. Despite virtually unavoidable excessive reliance on automated detection in hadron colliders, their development has been deemed a priority because they can operate at currently highest energy levels. I suggest, however, that a focus on collisions at the highest achievable energy levels diverts funds from searches for potential anomalies overlooked due to tradeoffs at the previous energy thresholds. I also note that even in the same collision environment, different research strategies will opt for different tradeoffs and thus achieve different experimental outcomes. Finally, I briefly discuss current searches for anomalous process in the context of the previous analysis. (shrink)

This paper develops a means–end analysis of an inductive problem that arises in particle physics: how to infer from observed reactions conservation principles that govern all reactions among elementary particles. I show that there is a reliable inference procedure that is guaranteed to arrive at an empirically adequate set of conservation principles as more and more evidence is obtained. An interesting feature of reliable procedures for finding conservation principles is that in certain precisely defined circumstances they must introduce hidden particles. (...) Among the reliable inductive methods there is a unique procedure that minimizes convergence time as well as the number of times that the method revises its conservation principles. Thus the aims of reliable, fast and steady convergence to an empirically adequate theory single out a unique optimal inference for a given set of observed reactions—including prescriptions for when exactly to introduce hidden particles. (shrink)

In this note I examine some implications of stochastic interpretations of quantum mechanics for the concept of "charge without charge" presented by Wheeler and Misner. I argue that if a stochastic interpretation of quantum mechanics were correct, then certain shortcomings of the "charge without charge" concept could be overcome.