Today is a good day: I can rest in peace without working out my daily share of science popularization here, because I have something better to do, which will have a much more sizable positive effect for the diffusion of particle physics. In fact, I hold in my hands a brand new copy of Gian Francesco Giudice's book, "A Zeptospace Odyssey - A Journey into the Physics of the LHC". All I have to do is to explain to you why you really should buy, read, and give as a present this book to all your friends.

Gian Francesco Giudice

First of all, a word on the author. Gian Francesco Giudice is a brilliant theoretical physicist who has worked at the CERN laboratories in the Theory Division since 1993. His scientific career brought him in many places before that, but it originated in Padova University, the place where I myself studied and now work. He is only five years older than me, but together with my slow academic career they were enough to get me to enjoy him as a teacher in a course on Group Theory during my Ph.D. studies in Padova. Since then, there is respect and friendship among us, although I see him rarely.

Gian is a clear thinker and the Physics Department in Padova University aches for his escape, but he is always greeted warmly when he visits us. His last visit was two weeks ago, when he gave a very insightful lecture. It was only then that I learned about his book, silly me.

An introduction of the author would not be complete with a list of previous works. Giudice has authored dozens of important scientific publications, so before I get to describe his book, let me cite here a few recent articles. To make the list very short, I only pick papers with more than 50 citations produced in the last few years.

- "Towards a complete theory of thermal leptogenesis in the SM and MSSM", with A. Notari, M. Raidal, A. Riotto, A. Strumia . 56pp. Published in Nucl.Phys.B685:89-149,2004, cited 333 times.

- "Split supersymmetry", with A. Romanino. 28 pp.
Published in Nucl.Phys.B699:65-89,2004, cited 319 times.

- "Aspects of split supersymmetry", with N. Arkani-Hamed, S. Dimopoulos, A. Romanino. 51pp. Published in Nucl.Phys.B709:3-46,2005, cited 235 times.

- "The Well-tempered neutralino", with N. Arkani-Hamed, A. Delgado. 29pp.
Published in Nucl.Phys.B741:108-130,2006, cited 68 times.

- "The Strongly-Interacting Light Higgs", with C. Grojean, A. Pomarol, R. Rattazzi. 45pp. Published in JHEP 0706:045,2007, cited 95 times.

The Book: first impressions

The book is a nice-looking hardcover volume, published by Oxford University Press earlier this year. It is not thick enough to scare you away, and once you open it and start turning its pages, you get a feeling of the clean, tidily typeset and clearly readable text. You soon find dozen of beautiful pictures in black and white, few graphs all looking simple to understand, and absolutely no mathematical formulas. This is a book for everybody! But can it, given the subject ?

Yes, the subject: this is a book about the journey that the Large Hadron Collider at CERN has undertaken, a journey inside the smallest distance scales which will hopefully bring us to find new riches, and make humanity wealthier of knowledge on the physical world. Divided in three parts ("A matter of particles", "The starship of zeptospace", and "Missions in zeptospace"), it contains 13 sections whose titles appear indeed arcane: forces of nature, dealing with naturalness, supersymmetry, from extra dimensions to new forces. Can this be a book for everybody after all ?

Of course it can! As I recently argued here, no scientific concept is too hard to explain to a reader willing to make a sincere effort. Only, it takes the most capable writer to do the trick. And Gian Francesco is a sublimely capable writer!

I am probably not the best of judges for what concerns the English prose of the book -I am Italian, just as Giudice is-, but I must say that I find the text exceedingly clear and well written. The author makes a real effort to not only explain in the simplest way, and with plenty of spot-on analogies, all the concepts that he believes are necessary in order to perform this journey, but he manages to make the reading quite enjoyable in the meantime! The book is a real mine of anecdotes intertwined with physics explanations, such that it reads very easily and you absorb a wealth of knowledge in the process almost without realizing it.

Let me make a few examples to explain what I mean here. If you are a reader of this blog you must know that I appreciate analogy as a powerful means to make tough physics concepts understandable; if you are not one, you might get a proof of that by reading my recent explanation of electroweak unification using a cup of chocolate, for instance. Being fond of analogies, I could not help appreciating the witty and fun way by which Gian Francesco explains complicated mathematics such as renormalization, one of the toughest hurdles in making sense of the theory of quantum electrodynamics:

"Imagine that tomorrow is St Valentine's Day. You and your friend David Beckham go out shopping to buy presents for your respective wives. You enter a store an David chooses for Victoria 30 diamong chokers, 50 emerald bracelets, 60 fur coats plus some other expensive items. He keeps careful track of his expenditures, which total some megabillion zillion euros. You pick up a small bouquet of flowers, whose price isn't marked. In the confusion at the checkout counter, all your purchases are rung up together and the total bill aounts to some megabillion zillion euros. Must you really pay some megabillion zillion euros for a bouquet ? Of course not: all you have to do is take the difference between the total bill and David's share, and you find that you must pay only 19 euros and 99 cents.

Something similar happens in calculations of QED. Most of the results of these calculations are equal to colossal numbers (actually infinity). However, these results do not correspond to measurable physical quantities, as much as the total bill above does not refer to what you must actually pay. Once the result of a physical quantity is appropriately expressed in terms of other physical quantities, colossal numbers are subtracted from each other and the result is a perfectly reasonable small number [...]"

The book contains countless quotes from the actors of the play of XXth century physics. I am also a collector of quotes, yet I was happy to find several that I had never heard before. And Gian is quick also to explain things that other authors overlook, oftentimes by using quotations, some of which are of true historical importance. Take this introduction to the neutrino:

"The name "neutrino" was coined jokingly by Enrico Fermi [...] when, during a seminar in Rome, he was asked if the two particles were the same. "No," replied Fermi, "Chadwick's neutrons are large and heavy. Pauli's neutrons are small and light; they must be called neutrinos." Of course the pun is lost in the English translation: in Italian "neutrino" is the diminutive of "neutron" - "little neutron".

How many of you non-Italian speakers knew this ?

To end this section, I need to mention an accident, which I hope will clarify just how accurate this book is. I wanted to write a paragraph here where I would say that incomplete explanations are a problem of any book which attempts the arduous task of explaining tough science to outsiders. I wanted to make the point that it is virtually impossible to stop and make sense of ALL the crucial concepts that arise in an explanation of physical concepts needed to read back-to-back a 250-page-long book. I had spotted one early on: on page 24, one reads that "... general relativity is not just a reformulation of Newton's theory. It predicted new effects - like the anomalous precession of Mercury perihelion[...]".

Aha! Gian fails to explain what this is here. What the heck is the anomalous precession of the perihelion of Mercury ? A non-physicist reading this sentence might be rightfully upset! ...But does he ? He doesn't. A glance at the Index under "Mercury" will reveal that later in the book, on page 224-225, the mysterious planet is mentioned again. And there, eventually, the diligent reader will finally find an answer to his doubt!

So, I owe apologies to Gian Francesco for having doubted of the completeness of this lean but self-sufficient book.


No review of a book would be complete without at least an attempt at criticizing its contents. I have read the book, and as I already said I found it clean, well written, and remarkably precise. I have nothing to say about the topics: the book covers the history of physics which lead to today's accelerators, the construction of the monster apparata, all the important goals of the LHC, not sparing even the most complex, cutting-edge theories of new physics. However, as they say "there's always one more bug". So let me have a shot at it. My list will be exceedingly short.

1. On page 27, talking of protons accelerated by the Bevatron in 1955, Gian says that "The proton energy was enormous for those days, but is actually less than a thousandth of the energy of a single LHC beam." Of course, he means "the energy of a proton in a LHC beam". The energy of a single LHC beam is trillions of times larger, being contributed by billions of protons.

2. It feels bad to criticize a very well-compiled Index, which is 20-pages long and is a quite useful addition to such a quotation-full book. However, the duty of the reviewer forces me. On page 276 the Index cites a "Wiloczek, Frank" which three lines above is correctly reported to reference two different pages as "Wilczek, Frank". The reference to page 71 should be thus added three lines before, and this line deleted. To be frank (with a lowercase f), the page-71 reference to Wilczek is correctly appearing on page 268, in the reference to "Nobel Prize".

3. As I already mentioned, the English in the text is quite correct and flowing. This is not surprising, given that if you heard Gian Francesco talk you might well exchange him for a Brit (the lack of typical Italian straggling of words in his pronunciation is remarkable). Even commas are used appropriately, following the so-called "Harvard comma" rule for serial lists (a comma is due before the last "and"). However, I found an inconsistent use of British versus American English spelling. On page 10 we read the word "color" and just one line below the word "odour". Who cares, you might ask! True, who cares. But since even 2000-strong scientific collaboration end up arguing at such level of detail on their drafts of scientific publications, I thought I would mention it...

A short interview with the author

Gian was kind enough to answer a few questions on his book for this blog. Here are five questions I posed, and his answers (in Italics):

1 - I am curious to know what brought you to the idea of this book, because I had no previous recollection of popularization activities on your part. What played a major role in deciding to write it: opportunity (being the right person in the right place and with the right means to write a very good account of the LHC adventure), desire to involve more people in the science we do, a challenge with yourself ? Or something else ?

It all started with some public lectures I gave on LHC physics. It was a surprise for me to see first hand how so many people, even those with no physics background, are sincerely fascinated by this wonderful scientific adventure. But at the same time I was really taken aback to see how the media coverage and newspaper articles were grossly misrepresenting the real aims of the LHC, feeding wrong information to the public. Explaining our research activity in simple and accessible terms does not necessarily require being scientifically inaccurate. So I decided to tell the story from a physicist's point of view. Any tale is more enticing when narrated by someone who is participating in the story.

2 - The text is quite clean and devoid of complications - there are no formulas, no graphs, and even the use of scientific notation for numbers is introduced by an apology. When you wrote your book did you aim at the widest possible audience, or was your choice of material rather driven by a specific target (such as, by means of example, high-school students) ?

The book is directed to anyone who is curious about the world of particle physics and the LHC. I made an effort to avoid technical terms and make sure that readers with no physics background could follow the story. But hopefully even physicists (especially young physicists) working at the LHC might find in the book elements that can help them broaden their views on their experiment and their field.

3 - Did anybody help you find and choose the dozens of appropriate quotations that are used in the book to introduce chapters and even subsections ? Their breadth is remarkable.

I like to read and this helped me. The quotations I collected from various authors and disciplines are mostly meant to bring a touch of irony in the presentation of a scientific field that most people believe to be high-browed and arcane. But they are also meant to show how physics is intertwined with other creative, artistic and speculative human activities.

4 - I know very well that you are a busy scientist, and your time is precious. Decreasing your involvement in your studies is probably out of the question, even for a noble goal like that of writing a popularization book on particle physics. How long did it take you to write this book ? Did you take a leave from work to finish it, or did you overburden your summer vacations, or did you instead proceed slowly by using your spare time in tiny bits ?

Finding the time to write was the most serious difficulty I had to face. The project took me about a year, and nights and weekends were my favourite writing periods. My family has been very kind and patient during that time.

5 - Although any book like yours is one of a kind, there always exist similarities in the way they are constructed, or in some choices like the material covered or the depth with which topics are discussed. Did you find inspiration in any previous book by particle physicists? Is there a model you followed ?

I read many books related to particle physics before and during the writing, and I learned much from them. Many of these great books have certainly influenced the way I view the development of our field and the meaning of the LHC. I absorbed this material, but I don't think I followed one particular book or author as a model. Instead I tried to adopt a writing style which is just a crossover from the style of my seminars and public lectures. I like to link ideas and developments in science with their historical context and to present advanced concepts in theoretical physics using simple and familiar analogies.

What others think

If you got this down in my review, you will no doubt have gotten the impression that I was paid very well for my lip service! No kidding: the fact is, my salary was a copy of the book, and my reward in writing the review was ... writing the review! I did not need to lie in the least. But to show you that I am in good company in appreciating Giudice's work, below I attach a short list of reviews on Giudice's book by unsuspectable arbiters.

"Gian Giudice has, as one would expect from such a clear and original thinker, produced a book which both challenges and excites, providing fresh insights into the domain of particles and their interactions. " - Ken Peach, University of Oxford and Royal Holloway University of London.

"This fascinating book is entertaining and comprehensible, leading the reader to the world of extremes: the high technology of the Large Hadron Collider at CERN and its huge particle detectors, the quest for the Higgs particle and the mysterious Dark Matter, and the theories of superstrings and extra dimensions at the verge of human imagination." - Thomas Lohse, Humboldt University, Berlin, Germany.

"I enjoyed this book tremendously. The weaving of important information with fun facts and anecdotes was awesome." - Savas Dimopoulos, Stanford University.

"This book shows that it is possible to describe to non-experts the frontiers of modern physics, in a way which is both faithful and comprehensible. I almost envy the author his right-on-the-bull's-eye explanatory metaphors. I believe that this book will become required reading for anyone interested in the reality of our world and in scientific human endeavour." - Riccardo Barbieri, Scuola Normale Superiore, Pisa, Italy.

"Gian Giudice provides a comprehensive introduction to the LHC as only a physicist working in the field could do." - Lisa Randall, Harvard University.

"Gian Giudice has given us a charming, comprehensive, and deep yet easily readable description of the history, technology, and scientific aspirations of the Large Hadron Collider, perhaps the greatest scientific experiment ever." - Gordon Kane, University of Michigan.

"This book, written by one of the leaders of the field, has a number of outstanding qualities: it is brilliant, original, comprehensive, entertaining and clear. It is a must for cultivated, non specialist readers who want to get an introduction to contemporary particle physics and to the exciting programme of the Large Hadron Collider of CERN." - Guido Altarelli, University of Rome and CERN.

"Gian Giudice has drawn on his deep understanding of physics to write a wonderful book, presenting the central ideas underlying the grand intellectual adventure of particle physics in an engaging and thought-provoking way. A must read for anyone who wants to understand the big questions we face in fundamental physics, and the ways we are tackling them." - Nima Arkani-Hamed, Institute for Advanced Study, Princeton.

A final advice

Buy the book. Read it, appreciate it, and then buy more copies as a gift for friends and relative of yours who think they would not understand particle physics for the life of them. They will be grateful!