Particle Astrophysics , Donald Perkins Oxford U. Press, New York, 2003. $99.50, $44.50 paper (256 pp.). ISBN 0-19-850951-0, ISBN 0-19-850952-9 paper
Some of the most perplexing cosmic and astrophysical phenomena are inextricably intertwined with the quantum world of elementary particles. Cosmologists have developed a “concordance model” that accounts for the observed global properties of the universe and the cosmic structures that were probably seeded by primordial quantum fluctuations. The standard model of particle physics accommodates all experimentally observed properties of elementary particles. But it completely fails to account for key elements of the concordance model—the dark matter that dominates the dynamics of galaxies and the dark energy that accelerates the expansion of the universe. Nor can it explain the cosmic preponderance of ordinary matter over antimatter, an asymmetry necessary for our very existence. Well-motivated extensions of the standard model suggest novel particles as dark-matter candidates. Such particles may well show up at new particle accelerators, in one of the many dedicated dark-matter searches, or as an annihilation signature in cosmic-ray observatories.
Cosmic rays may help identify dark matter; independent of that possibility, the field of cosmic-ray physics is rapidly advancing. The largest-ever observatories for cosmic rays, high-energy photons, neutrinos, and gravitational waves are now coming on line. Neutrinos in particular provide a showcase example for the synergy between astro- and particle-physics ideas and methods. Flavor oscillations, which imply that neutrinos have mass, have now been established by detailed observations of solar, atmospheric, and laboratory neutrino fluxes. Neutrinos cannot possibly be the dark matter—something more exotic is needed—but, surprisingly, in the framework of so-called leptogenesis scenarios they are intimately related to the cosmic matter–antimatter asymmetry.
Astroparticle physics, which covers the above and a diverse range of related topics, has begun to develop its identity as an independent research field with dedicated conferences, journals, university chairs, and even research centers and networks. Still, while excellent textbooks exist for cosmology, cosmic-ray physics, gravitational physics, and neutrino physics, few texts cover the full range of astroparticle physics. One notable exception is the excellent book Cosmology and Particle Astrophysics (Springer-Verlag, 2004) by Lars Bergström and Ariel Goobar, which has just appeared in its second edition.
Particle Astrophysics , by Donald Perkins, emeritus professor of physics at Oxford University, is another complete treatment, aimed at final-year undergraduate or beginning graduate students. It is largely based on the author’s hugely successful Introduction to High Energy Physics , which has seen four editions since 1972. The latest one (Cambridge U. Press, 2000), now in its third printing, includes a single chapter on cosmology. In Particle Astrophysics , on the other hand, three chapters cover cosmology, two treat particle physics, and a chapter each is devoted to cosmic particles (including neutrinos and gravitational waves) and to stellar evolution. The text is interspersed with worked examples. Each chapter has a concise summary and an extensive set of problems ranging from the trivial to the challenging. Answers or detailed solutions are provided at the end of the book, along with a somewhat limited bibliography. Particle Astrophysics covers a lot of ground and touches on many topics. It will be a useful resource for professors and a helpful supplemental text for students.
In spite of its obvious virtues, however, I could not really warm to the book. The synergy between chapters is minimal, the choice and weight of different topics are often poorly adjusted to the main story line, and the perspective is often outdated. For example, the text uses about a page to swiftly dispose of the astrophysical evidence for dark matter and then gives five pages to gravitational microlensing. But it never says that the crucial microlensing experiments it describes have excluded compact stars as a dominant dark-matter component and thus have strengthened the case for particle dark matter. Although neutrino oscillations are mentioned briefly in the cosmic-particles chapter, I find it bizarre that the particle-physics chapters are written as if the fantastic recent developments had never happened. Even Super-Kamiokande is introduced exclusively as a proton-decay detector.
That the universe may serve as a laboratory to test new particle-physics ideas is completely ignored. From this book, one would never guess that cosmology provides the most significant information on neutrino masses or that astrophysical arguments constrain numerous extensions of the standard model. I have complaints about many details and annoying errors, but what I am missing most is a coherent, contemporary presentation of astroparticle physics and a sense of real enthusiasm for this exciting field.
