Subject Grouping: Praxis

By Takaaki Kajita

World Scientific

This book on neutrino oscillations is mainly of historic interest. It consists of seven chapters that reproduce review articles written by the 2015 Nobel laureate in physics, Takaaki Kajita, which were previously published between 2000 and 2009, either in journals or in international conference proceedings (all World Scientific publications). The articles describe experiments on solar and atmospheric neutrino interactions performed using the Kamiokande and SuperKamiokande water Cherenkov detectors installed in the Kamioka mine in Japan. These experiments resulted in the 1998 discovery of atmospheric muon-neutrino (ν_μ) oscillation by observing ν_μ disappearance over a flight-path length of the order of the Earth’s radius. In addition, they have provided important hints on the oscillation of solar neutrinos, which was conclusively demonstrated in 2002 by the SNO experiment in Canada (the 2015 Nobel Prize in Physics was also awarded to A B McDonald for his leading role in this experiment).

Chapter 1 includes a short description of results from experiments using neutrinos from accelerators. These include the K2K experiment in Japan and MINOS at Fermilab, which confirmed the atmospheric neutrino oscillation, and the KamLAND experiment (also located in the Kamioka mine), which has observed the disappearance of electron antineutrinos (ν_e) from nuclear reactors over an average baseline of 180 km, therefore verifying solar-neutrino oscillation with “man-made” neutrinos. Although not up to date, the values of the oscillation parameters Δm²₁₂, Δm²₂₃, θ₁₂ and θ₂₃ quoted in this book are quite precise and close to the current ones.

Future directions and plans in the study of neutrino oscillations are also described. In particular, methods and plans to measure the mixing angle θ₁₃ (not yet measured in 2009) using neutrinos from both reactors and accelerators are discussed, as well as the impact of the θ₁₃ value on the possible detection of CP violation in the neutrino sector. Although the book was published in 2016, on this subject it is obsolete because θ₁₃ has been measured in the first half of the current decade by a number of experiments and is presently known to better than 10%.

Finally, chapter 2, written with four co-authors, addresses the physics capabilities of possible future experiments using a water Cherenkov detector with a mass of 1 Mton.

By A Zichichi

World Scientific

The book is a tribute to the great experimental physicist Lord Patrick M S Blackett, written by one of his pupils at the Sphynx Observatory, Antonio Zichichi. Blackett is well known for his work on cloud chambers and cosmic rays, which earned him the Nobel Prize in Physics in 1948.

The author offers his personal testimony, from the first time he heard Blackett’s name to when he went to work with him, and then about the research he could be involved in. He provides a profile of his subject while giving an overview of Blackett’s work and, in particular, of his most significant discoveries, including the so-called vacuum-polarisation effect, the first example of “virtual physics”, and strange particles. The important implications of Blackett’s pioneering contribution to sub-nuclear physics are also discussed.

The book also presents a portrait of the world of physics during those times, and gives insights into life and research at CERN, as well as about Blackett’s ideas. He was very interested in the role of science in the culture of the time. He was convinced that physicists should be directly engaged with communicating to society, which should be informed about the contribution of science to the progress of our civilisation.

Rich in personal anecdotes, pictures and appendices, the book could appeal to physicists and students who are also interested in the history of science and in the human dimension of great scientists. As a final point, the layout and editing could be improved.

By Fumihiko Suekane

Springer

Also available at the CERN bookshop

This is a detailed and up-to-date textbook on neutrino oscillations. After a short historical introduction (chapter 1), chapter 2 contains a concise, yet quite complete, presentation of neutrino theory in the Standard Model, including neutrino interactions and production in pion, muon and nuclear beta decay. The basic ideas of particle oscillation in quantum mechanics are introduced in chapter 3, and a detailed theory of neutrino oscillations is presented in chapter 4 – first in a two-neutrino approximation, then generalised to the three neutrino flavours – for oscillations both in vacuum and matter. In addition to the usual neutrino description in terms of plane waves, this chapter includes the mathematical treatment of a wave-packet oscillation, which helps in understanding neutrino oscillations over astronomical distances.

Chapter 5 contains a description of past and present oscillation experiments and of the results published prior to 2014, including the measurement of θ₁₃. These results are again summarised in chapter 6, where the current knowledge of three-neutrino oscillation parameters is described. Future experiments to measure the remaining oscillation parameters (the so-called neutrino mass hierarchy and the CP-violation phase) are discussed in chapter 7, together with oscillation anomalies observed by a number of experiments (LSND, MiniBoone, Gallium and recent re-analyses of old reactor experiments). These anomalies, if confirmed, would imply the existence of at least one additional “sterile” neutrino with a mass in the order of 1 eV, requiring a mixing matrix of larger dimensions and more oscillation parameters. Chapter 7 also includes a discussion of the difference between Dirac and Majorana neutrinos, and the implications of direct measurements of the effective ν_e mass and of searches for neutrinoless double beta decay. Finally, chapter 8 contains a useful appendix summarising all the symbols, abbreviations and formulae used in the book.

The textbook contains all of the information that anybody interested in neutrino oscillations would like to know. Physicists involved in neutrino experiments should each have a copy in their private libraries.

By M Riordan, L Hoddeson and A W Kolb
University of Chicago Press
Also available at the CERN bookshop

The Superconducting Super Collider (SSC), a huge accelerator to be built in Texas in the US, was expected by the physicists who supported it to be the place where the Higgs boson would be discovered. Instead, the remnants of the SSC facilities at Waxahachie are now property of the chemical company Magnablend, Inc. What happened in between? What did go wrong? What are the lessons to be learnt?

Tunnel Visions responds to these historical questions in a very precise and exhaustive way. Contrary to my expectations, it is not a doom and gloom narration but a down to earth story of the national pride, good physics and bad economics of one of the biggest collider projects in history.

The book depicts the political panorama during the 10 years (~1983–1993) of life of the SSC project. It started during the Reaganomics, hand in hand with the International Space Station (ISS), and concluded during the first Clinton presidency after the 1990s recession and the end of the Cold War. The ISS survived, possibly because political justifications for space adventure are easier to find, but most probably because from the beginning it was an international project. The book explains the management intricacies of such a large project, the partisan support and disregard, until the final SSC demise in the US congress. For the particle-physics community this is a well-known tale, but the historical details are welcome.

However, the book is more than that, because it also sheds light on the lessons learnt. The final woes of the SSC signed the definitive opening of the US particle-physics community to full international collaboration. For 50 years, without doubt, the US had been the place to go for any particle physicist. Fermilab, SLAC and Brookhaven were, and still are, great stars in the physics firmament. Even if the SSC project had not been cut, those three had to keep working in order to maintain the progress in the field. But that was too much for essentially a zero-sum budget game. The show must go on, so Fermilab got the main injector, SLAC the BaBar factory, and Brookhaven the RHIC collider. Thanks to these upgrades, the three laboratories made important progress in particle physics: top quark discovery; W and Z boson precision measurements; Higgs boson mass hunt narrowing between 113 and 170 GeV; detection of possible discrepancies in the Standard Model associated with b-meson decay; and the discovery of the liquid-like quark–gluon plasma.

Why did the SSC project collapse? The authors explain the real reasons, not related to technical problems but to poor management in the first years and the clash of cultures between the US particle-physics community and the US military-industrial system. But there are also reasons of opportunity. The SSC was several steps beyond its time. To put it into context: during the years of the SSC project, at CERN the conversion of the SPS into a collider took place, along with the whole LEP programme and the beginning of the LHC project. That effort prevented any possible European contribution to the SSC. The last-ditch attempt to internationalize the SSC into a trans-Pacific partnership with Japan was also unsuccessful. The lessons from history, the authors conclude, are that at the beginning of the 1990s the costs of frontier experimental particle physics had grown too much, even for a country like the US. Multilateral international collaboration was the only way out, as the ISS showed.

The Higgs boson discovery was possible at CERN. The book avoids any “hare and tortoise” comparison here, however, since in the dawning of the new century, the US became a CERN observer state with a very important in-kind contribution. In my opinion, this is where the book grows in interest because it explains how the US particle-physics community took part in the LHC programme, becoming decisive. In particular, the US technological effort in developing superconducting magnets was not wasted. The book also talks about the suspense around the Higgs search when the Tevatron was the only one still in the game during the LHC shutdown after the infamous incident in September 2008.

Useful appendices providing notes, a bibliography and even a short explanation of the Standard Model complete the text.

By Arieh Ben-Naim
World Scientific

In this book, the author explains entropy and the second law of thermodynamics in a clear and easy way, and with the help of many examples. He intends, in particular, to show that these physics laws are not intrinsically incomprehensible, as they appear at first. The fact that entropy, which is defined in terms of heat and temperature, can be also expressed in terms of order and disorder, which are intangible concepts, together with the evidence that entropy (or, in other words, disorder) increases perpetually, can puzzle students. Some mystery seems to be inevitably associated with these concepts. The author asserts that, looking at the second law from the molecular point of view, everything clears up. What a student needs to know is the atomistic formulation of entropy, which comes from statistical mechanics.

The aim of the book is to clarify these concepts to readers who haven’t studied statistical mechanics. Many dice games and examples from everyday life are used to make readers familiar with the subject. They are guided along a path that allows them to discover by themselves what entropy is, how it changes, and why it always changes in one direction in a spontaneous process.

In this second edition, seven simulated games are also included, so that the reader can experiment with and appreciate the joy of understanding the second law of thermodynamics.

By Ethan Siegel
World Scientific

This book provides an introduction to astrophysics and cosmology for absolute beginners, as well as for any reader looking for a general overview of the subject and an account of its latest developments.

Besides presenting what we know about the history of the universe and the marvellous objects that populate it, the author is interested in explaining how we came to such knowledge. He traces a trajectory through the various theories and the discoveries that defined what we know about our universe, as well as the boundary of what is still to be understood.

The first six chapters deal with the state-of-the-art of our knowledge about the structure of the universe, its origin and evolution, general relativity and the life of stars. The following five address the most important open problems, such as: why there is more matter than antimatter, what dark matter and dark energy are, what there was before the Big Bang, and what the fate of the universe is.

Written in plain English, without formulas and equations, and characterized by a clear and fluid prose, this book is suitable for a wide range of readers.

By Jeffrey Bub
Oxford University Press

This is not another “quantum mechanics for dummies” book, as the author himself states. Nevertheless, it is a text that talks about quantum mechanics but is not meant for experts in the field. It explains complex concepts of theoretical physics almost without bringing up formulas, and makes no reference to a specialist background.

The book focuses on an intriguing issue of present-day physics: nonlocality and the associated phenomenon of entanglement. Thinking in macroscopic terms, we know that what happens here affects only the surrounding environment. But going down to the microscopic level where quantum mechanics applies, we see that things work in a different way. Scientists discovered that in this case, besides the local effects, there are less evident effects that reveal themselves in strange correlations that occur instantaneously between remote locations. Even stronger nonlocal correlations, still consistent with relativity, have been theoretically supposed, but have not been observed up to now.

This complex subject is treated by the author using a particular metaphor, which is actually more than just that: he draws a metaphoric world made of magic bananas, and simple actions that can be performed on them. Thanks to this, he is able to explain nonlocality and other difficult physics concepts in a relatively easy and comprehensive way.

Even if it requires some general knowledge of mathematics and familiarity with science, this book will be accessible and interesting to a wide range of readers, as well as being an entertaining read.

By Stephan Narison
World Scientific

This book aims to present the history of particle physics, from the introduction of the concept of particles by Greek philosophers, to the discovery of the last tile of the Standard Model, the Higgs boson particle, which took place at CERN in 2012. Chronologically following the development of this field of science, the author gives an overview of the most important notions and theories of particle physics.

The text is divided into seven sections. The first part provides the basics concepts and a summary of the history of physics, arriving at the modern theory of forces, which are the subject of the second part. It carries on with the Higgs boson discovery and the description of some of the experimental apparatus used to study particles (from the LHC at CERN to cosmic rays and neutrino experiments). The author also provides a brief treatment of general relativity, the Big Bang model and the evolution of the universe, and discusses the future developments of particle physics.

In the main body of the book, the topics are presented in a non-technical fashion, in order to be accessible to non-experts. Nevertheless, a rich appendix provides demonstrations and further details for advanced readers. The text is accompanied by plenty of images, including paintings and photographs of many of the protagonists of particle physics.

By Luca Lista
Springer
Also available at the CERN bookshop

Particle-physics experiments are very expensive, not only in terms of the cost of building accelerators and detectors, but also due to the time spent by physicists and engineers in designing, building and running them. With the statistical analysis of the resulting data being relatively inexpensive, it is worth trying to use it optimally to extract the maximum information about the topic of interest, whilst avoiding claiming more than is justified. Thus, lectures on statistics have become regular in graduate courses, and workshops have been devoted to statistical issues in high-energy physics analysis. This also explains the number of books written by particle physicists on the practical applications of statistics to their field.

This latest book by Lista is based on the lectures that he has given at his home university in Naples, and elsewhere. As part of the Springer series of “Lecture Notes in Particle Physics”, it has the attractive feature of being short – a mere 172 pages. The disadvantage of this is that some of the explanations of statistical concepts would have benefited from a somewhat fuller treatment.

The range of topics covered is remarkably wide. The book starts with definitions of probability, while the final chapter is about discovery criteria and upper limits in searches for new phenomena, and benefits from Lista’s direct involvement in one of the large experiments at CERN’s LHC. It mentions such topics as the Feldman–Cousins method for confidence intervals, the CLs approach for upper limits, and the “look elsewhere effect”, which is relevant for discovery claims. However, there seems to be no mention of the fact that a motivation for the Feldman–Cousins method was to avoid empty intervals; the CLs method was introduced to protect against the possibility of excluding the signal plus background hypothesis when the analysis had little or no sensitivity to the presence or absence of the signal.

The book has no index, nor problems for readers to solve. The latter is unfortunate. In common with learning to swim, play the violin and many other activities, it is virtually impossible to become proficient at statistics by merely reading about it: some practical exercise is also required. However, many worked examples are included.

There are several minor typos that the editorial system failed to notice; and in addition, figure 2.17, in which the uncertainty region for a pair of parameters is compared to the uncertainties in each of them separately, is confusing.

There are places where I disagree with Lista’s emphasis (although statistics is a subject that often does produce interesting discussions). For example, Lista claims it is counter-intuitive that, for a given observed number of events, an experiment that has a larger than expected number of background events (b) provides a tighter upper limit than one with a smaller background (i.e. a better experiment). However, if there are 10 observed events, it is reasonable that the upper limit on any possible signal is better if b = 10 than if b = 0. What is true is that the expected limit is better for the experiment with smaller backgrounds.

Finally, the last three chapters could be useful to graduate students and postdocs entering the exciting field of searching for signs of new physics in high energy or non-accelerator experiments, provided that they have other resources to expand on some of Lista’s shorter explanations.