## Monday, October 26, 2015 ... /////

### From the Great Wall to the Great Collider

Video bonus: Nima's talk about the collider project (Breakthrough Symposium)

I received a copy of this beautiful book by Shing-Tung Yau and Steve Nadis that has increased my excitement about the possible future 100-kilometer $100\TeV$ Great Collider of China.

Be ready for a 200-page book whose pages' area is greater than most books. Lots of the pages show photographs of physicists, experimental devices and facilities, and similar things. The book has its own domain, TheGreatCollider.com (comment added on Tuesday).

The name "Great Collider" has been coined by David Gross, along with the analogies with the Chinese representative among the Wonders of the World. His ancestors helped to build the Wailing Wall which is smaller but similar. And the relationship between the Great Wall and the Great Collider is not just an analogy. The Great Collider should be built near the Eastern end of the Great Wall of China. Its length, 100 kilometers, would still be modest in comparison with the 21,000 kilometer of the wall (this is the total length of all segments where any traces of a wall have been found by 2012; other numbers may be shorter) but it would still be by far the largest machine built by the humans.

Shing-Tung Yau is a top geometer at Harvard, the man who proved the Calabi conjecture and established the industry of the Calabi-Yau manifolds. This topic was nicely described in The Shape of Inner Space, the first book by this duo. The new book about the Chinese accelerator was written in a similar way: Yau contributed most of the knowledge (at least the expert knowledge), understanding, experience, and fame, while Nadis has mostly contributed his unusually good communication and English skills. But this role assignment may be wrong.

The Great Wall was protecting China against the invaders by the Mongol savages from the North. This terrestrial defense has become less important in recent years. But the Great Collider would protect China's place among the high-tech, curious, and civilized nations.

At the beginning of the book, Nadis says that he recently visited China for the first time and he saw that the famous ancient empire is also a more modern country than the U.S. from many respects. Yau starts by some stories about his early career in the U.S. He was a young geometer with some hobby-like interest in physics and was thinking about the vacuum solutions of Einstein's equations – and got to the Calabi-Yau manifolds in this way.

I was impressed by a rather detailed history of particle physics from Democritus to Lawrence's first cyclotron and the Dirac equation to some recent developments. If you know Shing-Tung Yau as the author of the highly abstract mathematical papers, you could think that he's largely detached from the real world in general and physics in particular. But Yau – or maybe Nadis – will prove you wrong. The book contains many more details about the history and discoveries of the individual quarks and leptons as well as the important advances in accelerator technology than almost any book written by a theoretical physicist! Yau is an important enough voice in the Chinese scientific establishment and we learn that he's one of the "Holy Trinity" that supervises the planning of the Great Collider of China.

The support for Big Physics on the American continent has been substantially weakening in the recent 25 years and the idea that China should become the new leader was growing at several places. I remember Nima Arkani-Hamed as a super-enthusiastic man but Yau and Nadis quote Nima's pessimistic statements about the U.S. relationship to Big Physics. Many words had to be redacted; for example, the word "[screwed]" had to replace Nima's more colorful jargon. And Nima has repeated the slogan "What about China?" so many times that some other people have finally converged to a bold idea: What about China? :-)

Aside from Nima and Yau, Yifang Wang – a top Chinese particle physicist, according to both research and politics – is counted as a member of the Holy Trinity of the Great Collider. Many other famous physicists including Nobel prize winners have attended meetings designed to consolidate the support for the project.

It's mind-boggling if not mind-blogging to imagine 21,000 km of this high-tech infrastructure. On the other hand, whether it's possible to build such a thing with hundreds of millions or billions of workers, depends on the $\infty/\infty$ indeterminate ratio.

China has been one of the oldest civilizations. Yau and Nadis remind us of the more recent contributions to fundamental physics by the Chinese – e.g. Lee and Yang (theory) and Wu (experiment) who showed that the weak interaction violates the left-right symmetry. Yang is later discussed in the context of Yang-Mills theory, too. And Samuel Ting got his Nobel prize for the co-discovery of the charm quark (through the $J/\psi$ meson). However, most of these successful Chinese folks made their important work on the external side of the Great Wall of China and it would make sense for China to try to reabsorb some of this prominent intellectual and technological activity.

OK, after the first "standard" chapter on the history of accelerators and the discovery of elementary particles from the electrons to the top quarks, there is a whole second chapter on the story of the Higgs boson. One may read not only about the well-known history and analogies – the Higgs field makes the pudding denser; it's like a phase transition, and it's like Margaret Thatcher that changes how the journalists clump in a crowded room. Yau and Nadis quote lots of physicists and the composition makes it clear that Yau is very close to the cream of the research community. They quote folks like Matt Strassler, Dan Hooper, Gordon Kane, Brian Greene, Lisa Randall, Juan Maldacena, Edward Witten, Nathan Seiberg, Nima Arkani-Hamed, Robbert Dijkgraaf, Joe Lykken etc. and similarly prominent LHC experimenters. For example, Lisa offers the analogy of the spontaneous symmetry breaking with the unstable pencil standing on the tip. My inbox indicates that Lisa actually knows this analogy from me. I have brainwashed her with that analogy from 2002 to 2012 and it was finally successful. ;-)

The Higgs chapter also discusses some details about the inner workings of the LHC as well as the history of the growing Higgs bumps. The book mentions the Superconducting Supercollider and a former GOP lawmaker is quoted as saying "no true American patriot would care about things as silly as a f*cking Universe". OK, I have improved the (already embarrassing) quote a little bit. While the depth of the technical detail has already exceeded my expectations, they promise a discussion of the WW scaterring (a professional physicist's way to see that the Higgs boson has to exist) in chapter 5!

And the third chapter already goes beyond the Standard Model! (BTW Yau and Nadis agree with Wilczek and a few others that the term "Standard Model" sounds too disrespectful to them.) The Standard Model seems great, sufficient for all the observations we have made, and consistent up to much higher energies. But the history of science is full of people who claimed "game over" prematurely. And the Standard Model has some bugs. They discuss some defects and dark matter etc. before they switch to solutions. Much of the chapter is about supersymmetry – with an updated discussion of some scenarios and the relevance of SUSY for dark matter etc. Some experimenters, especially those from Harvard – Melissa Franklin and Masahiro Morii – were also asked to explain their feelings about the discovery prospects etc. There's also some discussion of the extra dimensions and Higgs compositeness as well as the other proposed future colliders and the claim that the Great Collider of China (or its tunnel) should first be used as a lepton $240\GeV$ accelerator before it would be turned into a $100\TeV$ hadron machine.

I was in the middle of the book – somewhere in this chapter – when I became certain that the book covers very many ideas and facts and is insufficiently structured according to my taste. The main part of the book consists of 6 chapters and they have no further substructure. So for example, all the topics described in the previous paragraph are continuously blended with each other. I admit that my preferred writing and reading style includes not only sections but maybe also subsections (and, to be honest, I think in terms of subsubsections as well but when I write things down, I hide them not to allow the visually hierarchical architecture of my texts get out of control).

The fourth chapter focuses on the already available signs of the proposed future leading role of China in particle physics. China is accepted to lag behind the West in fundamental physics but numerous important Chinese researchers at the South Pole (BICEP) and similar experiments are mentioned, along with PandaX, an underground lab in Tibet eager to compete e.g. with Gran Sasso. Sam Ting has his AMS, of course. Many pages are dedicated to the neutrino experiments, even though the book was completed before the 2015 Nobel prizes were distributed. It was nice to see that the book offers you the (balanced) information about the current status of many experiments – as of Summer 2015. Note that Daya Bay is the big neutrino experiment by 6 countries – the Chinese Triplet (PRC, Taiwan, Hong Kong) along with the three most important non-Chinese countries (America, Russia, and Czechia – the first three countries with astronauts). PandaX is working in tunnels underground and I am sure that the Czech Little Mole could be helpful for the panda here, too. ;-)

There are several examples of "smaller" experiments and the Chinese folks in them and lots of data are presented. At some moment, I started to be overwhelmed and bored and needed some laugh or an idiosyncratic story. And it did arrive. You know, it's a book published in the U.S. and resembles other popular books but at the end, it's a book promoting the leading role of a country run by a communist party, right? Yau and Nadis tell us some insider stories about Yang who visited China in 1971 when the conditions got more liberalized in the People's Republic. Yang could have talked to Mao himself – even though it was through the prime minister Zhou only – and Mao was supportive of the basic research. So some first Chinese accelerator experiments could begin by the late 1970s, with some help from SLAC (Panofsky, the boss of SLAC, refused a Chinese salary to keep his independence).

In general, the Chinese language isn't similar to the poultry sounds. It's just this popular song.

I guess that if the Chinese government demands the collider to be called the Mao Collider, Nima and others will agree – and so would I. :-)

The fifth chapter returns to the Great Collider of China. The story begins with the frustration caused by the cancellation as the SSC as well as the nightmare that the LHC will be the "Last Hadron Collider". Yau and Nadis accumulate a formidable amount of facts about the assorted future colliders that have been proposed, their proponents, their advantages and disadvantages, and lots of other things. It's a book by a mathematician and a science writer but it reads like a book by a faculty committee of 10 experimental and phenomenological particle physicists and their 15 graduate students and 20 secretaries. There's a lot of details about "circular vs linear" and "leptons vs hadrons" and the signatures, duplication between continents, cooperation between continents, economic consequences, and many other things. I expected some more theoretically flavored discussion of the WW scattering that was promised earlier but I must have overlooked it. This looks like a mandatory reading for the officials in the collider organizations.

The last, sixth chapter is shorter and is dedicated to practical applications of the research. Yau and Nadis discuss the legendary prediction by Faraday that the kingdom was going to tax electromagnetism at some point. Electronic and communication devices, tomographs and other machines in medicine, the web, and lots of other useful things that emerged because of the fundamental research are enumerated. The Great Collider will specifically help the Chinese development and economy, too. Fundamental physics is a/the top discipline of science which will help to decide whether the professors and other top brains actually feel the attraction to move to China or elsewhere. However, the most important spinoff is the knowledge itself. It is what makes us human.

Finally, the short epilogue talks about the Shanhai Pass and the greatest threat for the Great Wall of China. It's no longer the Mongol invaders. Instead, it's the international tourists who sometimes steal rocks and even if they happen to be law-abiding, they are collectively causing erosion of the wall. To make things worse, none of them probably knows that in 10 years, the Great Collider of China would be located beneath the tourist destination they are just visiting. In the past, the Great Wall was built to deter the Mongol troops, refugees, and immigrants but the Great Collider will have the (almost) opposite goal: to attract the brains from the world. Let's hope that particle physics – and the human search for curiosity – won't stop in the 21st century and the huge facility will serve the whole mankind, except for the tourists who are idiots, of course. ;-)

At the end, notes describe the sources of many quotes – many of those are taken from books and articles but some of them are coming from private conversations. The index is 10-page long.

If you are an intelligent Chinese person who speaks English (it's unlikely that you were able to access this page, thanks to the Great Firewall of China, another great Chinese thing) or someone who likes popular books about physics or if you have any relationship with the future collider experiments, you should definitely buy this book, too.