Neutrinos have been of great interest to physicists since Wolfgang Pauli first postulated their existence in 1930 to solve a puzzle with the decay of nuclei. But they are very elusive particles; they interact so weakly with ordinary matter that they can even pass through the Earth with little chance of interacting and hence being detected. Therein lies the challenge for experimental physicists.
Ray Jayawardhana begins with a brief history of neutrinos and tells how experiments eventually vindicated Pauli's postulate. This is followed by detailed accounts of the heroic experiments of early workers in this field, such as Ray Davis, who spend more than 20 years making painstaking measurements of the neutrino flux from the Sun. These eventually persuaded a doubting scientific community to revise its theories about the nature of neutrinos, and led to acceptance of the idea that different types of neutrino (of which there are three, plus their antiparticles) can morph into one another. This was a pivotal moment, because this phenomenon is only possible if neutrino masses are not exactly zero, has had been assumed in the so-called Standard Model of particle physics, and so opened up the exciting possibility that the Standard Model was not the last word. Later experiments confirmed that neutrino masses, although tiny even by the standards of particle physics, are non-zero, although even now we don't know precisely their individual masses, only their mass differences. Davis' experiment was large by the standards of his day, but modern experiments are often truly gigantic, involving major feats of engineering and frequently carried out in inhospitable places, such as more than one mile underground in a mine, or on the Antarctic ice shelf, some of which are described.
Neutrinos offer the possibility of answering some of the biggest questions in physics and cosmology, such as why is there massively more matter than antimatter in the universe. Had the Big Bang created a truly symmetry universe it would only consist of radiation and we would not exist. A possible solution to this puzzle may lie in the suggestion that the neutrino and its antiparticle are identical, and the author discusses experiments to test this hypothesis that are underway or in the planning stage. However, because they involve the simultaneous interaction of two neutrinos, they are even more difficult to detect than `simple' neutrino interactions and extraordinary care has to be taken to avoid contamination.
The last section of the book describes a range of possible applications of neutrino physics. Some of these, such as monitoring nuclear reactors to check that they are not being used to produce plutonium, or using neutrinos to probe the structure of the Earth's core, are undoubtedly possible, but would require a very large investment to be used generally. Others, such as using neutrinos to send encrypted messages through the Earth, rather than bouncing signals off satellites, are far more speculative.
There is much physics in this book, but inevitably it is explained fairly rapidly, and I suspect that readers without some prior knowledge of the subject will find it a bit hard going, although there is a useful Glossary that will help. The real strength of the book lies in the accounts of the experiments, where the author deftly weaves the science with biographical details of the participants. They are written in an informal style and are very well done. Overall, the author gives a good feeling for why neutrinos are such a major part of current research in particle physics and the enthusiasm of the scientists involved.
on 1 April 2014
The Neutrino Hunters is Ray Jayawardhana’s intriguing and informative concise history of both the highly elusive neutrino itself and of the peculiar, offbeat characters who made finding the least understood particle in physics their life’s work. Jayawardhana has a gift for making extremely complicated topics digestible for the layman and his enthusiasm for astrophysics in general and, of course, neutrinos in particular, is infectious. While he clearly doesn’t suffer from “neutrino fever” to the same extent of some of the real life mad scientists that he discusses, Jayawardhana vividly recounts what is currently known and neutrinos and convincingly postulates what further knowledge of the phantom particular could mean for science and humanity.
on 1 September 2014
Fantastically written, easy to access book which provides a good mixture of details on theoretical physics and the practical experiments used to investigate the theory. The book guides you through the fascinating history of the neutrino and the future of neutrino investigations. Throughout the book, the author provides a summarised biography of the key scientists in the search of the neutrino, which provided a really interesting human angle to the whole story. The glossary and timeline at the end of the book is a very useful tool for reference.