By Harald Fritzsch and Murray Gell-Mann (eds)
World Scientific
Also available at the CERN bookshop
This book was written on the occasion of the golden anniversary of a truly remarkable year in fundamental particle physics: 1964 saw the discovery of CP violation in the decays of neutral kaons, of the Ω baryon (at the Brookhaven National Laboratory), and of cosmic microwave background radiation. It marked the invention of the Brout–Englert–Higgs mechanism, and the introduction of a theory of quarks as fundamental constituents of strongly interacting particles.
Harald Fritzsch and Murray Gell-Mann, the two fathers of quantum chromodynamics, look back at the events that led to the discovery, and eventually acceptance, of quarks as constituent particles. Why should we look back at the 1960s? Besides the fact that it is always worthwhile to reminisce about those times when theoretical physicists were truly eclectic, these stories are the testimony of a very active era, in which theoretical and experimental discoveries rapidly chased one another. What is truly remarkable is that, even in the absence of an underlying theory, piecing together sets of disparate experimental hints, the high-energy physics community was always able to provide a consistent description of the observed particles and their interactions. In fact, it was general principles such as causality, unitarity and Lorentz invariance that allowed far-reaching insights into analyticity, dispersion relations, the CPT theorem and the relation between spin and statistics to be obtained.
In this volume, Fritzsch and Gell-Mann present a collection of contributions written by renowned physicists (including S J Brodsky, J Ellis, H Fritzsch, S L Glashow, M Kobayashi, L B Okun, S L Wu, G Zweig and many others) that led to crucial developments in particle theory. The individual contributions in the book range from technical manuscripts, lecture notes and articles written 50 years ago, to personal, anecdotal and autobiographical accounts of endeavours in particle physics, emphasising how they interwove with the conception and eventually acceptance of the quark hypothesis. The book conveys the enthusiasm and motivation of the scientists involved in this journey, their triumph in cases of success, their amazement in cases of surprises or difficulties, and their disappointment in cases of failures. One realises that while quantum chromodynamics seems a simple and natural theory today, not everything was as easy as it now looks, 50 years later. In fact, the paradoxical properties of quarks, imprisoned for life in hadrons, had no precedent in the history of physics.
The last 50 years has witnessed spectacular progress in the description of elementary constituents of matter and their fundamental interactions, with important discoveries that led to the establishment of the Standard Model of particle physics. This theory accurately describes all observable matter, namely quarks and leptons, and their interactions at colliders through the electromagnetic, weak and strong force. Yet many open questions remain that are beyond the reach of our current understanding of the laws of physics. Of central importance now is the understanding of the composition of our universe, the dark matter and dark energy, the hierarchy of masses and forces, and a consistent quantum framework of unification of all forces of nature, including gravity. The closing contributions of the book put this venture in the context of today’s high-energy physics programme, and make a connection to the most popular ideas in high-energy physics today, including supersymmetry, unification and string theory.
