Abstract: This talk will primarily analyse the prediction and discovery of the Omega minus baryon. The confirmation of the particle's existence was a turning point for the acceptance of Gell-Mann and Ne’eman’s theory of the Eightfold Way, affirming its empirical success. As a result, it lay the groundwork for the quark model by providing confidence in the viability of Eightfold Way and turning physicists towards a deeper investigation of the scheme's SU(3) structure.
The prediction of the Omega minus particle has been analysed by philosophers as a non-standard form of inference, primarily due to the involvement of group theory in making an existence claim. Prominent accounts include Bangu (2007), Ginammi (2015), Bueno and French (2018), and Tricard (2023). These authors present a variety of interpretations, but tend to treat the inference either as a heuristic in the context of discovery, or as relying on premises that lack justification. I will argue that the features of the Eightfold Way mean that the inference did feature heuristic arguments, but that they were justified precisely because of the group theory involved, alongside the explicitly tentative nature of Eightfold Way. In particular, I will propose a form of inference that I call possibility counting from symmetries (PCS), where the possibility space of certain theories are constructed based on group-theoretic tools, thereby justifying the prediction of new entities. Finally, I will consider implications and limitations of PCS for theories beyond the Eightfold Way, such as the Higgs mechanism and supersymmetry.
The PoP-Grunch (Philosophy of Physics Graduate Lunch) is a weekly informal seminar in which graduate students in Philosophy of Physics present their work in progress.
Philosophy of Physics Graduate Lunch Seminar Convenor: Paolo Faglia
