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May 01 2013

The Higgs Story-Part 20: Concluding thoughts (and bibliography)

It is time to wrap up what turned out to be a much longer series of posts on the Higgs than I anticipated when I started it, probably with a lot more information than readers wanted to know! (For previous posts in this series, click on the Higgs folder just below the blog post title.)

The story of the detection of the Higgs is a prime example of what Thomas Kuhn described as ‘normal science’ in his classic work The Structure of Scientific Revolutions (1962). He said that most of the time, scientists are not seeking novelty but instead are carefully looking for things in which almost everything is known and anticipated, except for a few minor details. In the case of the Higgs, experimenters knew almost everything about it except its mass, and even then we had some idea of the possible range of values. It should not be surprising that the final confirmation comes as somewhat of an anti-climax.

There are undoubtedly mixed feelings that the Higgs particle has been discovered. The positive reaction comes from the feeling of satisfaction that an important prediction of a major theory has likely been confirmed. The caveat of ‘likely’ is because it takes a long time to confirm all the auxiliary predictions that are associated with any discovery. What was actually announced last July was that two groups working independently using different detectors had obtained the first results that met the required statistical threshold for a particle that was consistent with the properties of the Higgs particle. Definite confirmation that it is indeed the Higgs will take some time but when (if?) that happens, science history will likely retroactively assign the seminar as the discovery date, although the two preprints by the two detector groups of the actual papers were submitted only on July 31, 2012 (see here for ATLAS and here for CMS) and were published simultaneously back-to-back in the September 17, 2012 issue of Physics Letters B.

The negative reaction is due to the fact that science is always more exciting when something turns up that is unexpected and counter to a prediction because that causes us to re-examine those theories that we thought were on a solid footing. As Kuhn said, the failure to see the strongly anticipated is what leads to suspicions that there may be a breakdown in the existing paradigm. If the problem cannot be resolved within the paradigm’s framework, this could lead to a crisis, with the old theory being viewed with suspicion and newer and better theories proposed as rivals, and thus lead to scientific revolutions. Clearly that has not happened here. So finding the Higgs after such a long, difficult, and exhausting search has left some physicists wondering, “So now what do we do?”

The feeling is somewhat akin to that of Wile E Coyote in this parody of the road runner cartoon, created by the people behind Family Guy (language advisory).

Glenn Starkman, a physicist colleague of mine at Case Western Reserve University captures, with some minor exaggeration, the sense of disappointment that the Higgs has been found and that what we call the Standard Model seems to be working so well, despite the hopes of many that some its problematic features may be signals that there might be new physics waiting to be discovered, and that the failure to find the Higgs may be what causes the edifice to crumble, leading to new and exciting discoveries.

The Standard Model is absurdly fine-tuned, we were told – balanced on a knife-edge off which it has no right not to tumble. It has an un-natural hierarchy of scales. It has too many free parameters, and some of them are very, very small. Why, the electron mass is less than 0.00001 times the weak scale (the energy scale governing weak interactions such as the W and Z boson masses), which is itself 10-17 (that 0.0000000000000001) times the Planck scale (the energy scale governing gravity)! And speaking of gravity, the Standard Model can’t accommodate quantum gravity. We need Low-Energy Supersymmetry, or Technicolor, or Large Extra Dimensions, or … One of these MUST be found at the LHC!

Forty years of theoretical work has been based on these expectations. Papers with thousands of citations have been written. Courses taught. Textbooks published.

Prizes awarded! Illustrious careers navigated! And yet despite all this build up of theoretical expectations, there is no experimental hint of anything outside the Standard Model at the LHC. Hence the long faces and worried words wherever theorists gather to drink coffee. Hence the disappointment in the eyes of the young experimentalists looking forward to the next accelerator, the next frontier where their mark will be made. It doesn’t even help to have been one of the few Cassandras belatedly warning that the edifice of Beyond the Standard Model theories might be built on sand. We want there to be more physics – more particles, more interactions. More to discover.

Walk the halls, go to theory seminars, have lunch with a theorist, or an ambitious young experimentalist. Look for the classic symptoms of grief.

Incidentally, this is one feature of science that religious people just can’t seem to grasp. Some of them have this idea that scientists propose multiverses or a time before the Big Bang or defend the theory of evolution in order to counter religious explanations. Nothing could be further from the truth. Religion has nothing to do with the fate of scientific theories, except in so far as the climate created by religion has an impact on the culture in which science is practiced. There is nothing that a scientist would like better than to overthrow a well-established theory and replace it with a better one because that would cement that scientist’s reputation in history, putting her in the ranks of a Newton, Einstein, or Darwin. The theory of evolution is defended because it is the best there is. The religious consequences are of incidental concern as far as the science goes.

Religious people will likely go on desperately hoping that science will lead us to the discovery of god’s existence. There will be some who, because of the unfortunate media mania generated by calling the Higgs ‘the God particle’, may seize on the speculation (see part 18 in this series) that the Higgs may be a portal to a new world of exotic particles to suggest that it may also open a window through which we can see god.

If so, they will be pursuing yet another blind alley because, as this series has sought to show, god has nothing to do with the Higgs particle, because he/she has nothing to do with anything.

Bibliography

There have been several books published since the discovery of the Higgs was announced, though clearly much of their content had been written earlier and the publishers were waiting for the announcement to release them

The Particle at the End of the Universe by Sean Carroll (2012) is a good book aimed at the general reader. Carroll is a good writer and knows his physics so he is a reliable guide.

Higgs: The Invention and Discovery of the ‘God Particle’ by Jim Baggott (2012) is one that I reviewed for the April 2013 issue of the American Journal of Physics (subscription only). It is aimed at the general reader but I had mixed feelings about it.

God and the Atom by Victor Stenger is one I just received from the publisher but have not read yet so cannot comment on it.

Some semi-popular articles:

The Higgs Boson Glossary in Science, vol. 338, p. 1558-1559 December 21, 2012 explains much of the technical jargon.

Journey in the Search for the Higgs Boson: The Atlas and CMS Experiments at the Large Hadron Collider by M. Della Negra, P. Jenni, T. S. Virdee in Science, vol. 338, 1560-1568, December 21, 2012.

A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider by the CMS Collaboration, Science, vol. 338, 1569-1575, December 21, 2012.

A Particle Consistent with the Higgs Boson Observed with the ATLAS Detector at the Large Hadron Collider by the ATLAS Collaboration in Science, vol. 338, 1576-1582, December 21, 2012.

Here are some websites that provide useful information with varying levels of difficulty.

Theoretical physicist Matt Strassler provides a nice set of posts that walks you through pretty much the same Higgs story as I did but more rigorously, with more math and less hand-waving, history, and philosophizing.

This site provides some basic definitions and data about the LHC.

This paper written in 2010 is a somewhat more technical work that discusses the relationship between theory and the searches for the Higgs boson.

6 comments

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  1. 1
    Rob Grigjanis

    Great series Mano. Thank you.

  2. 2
    MNb

    “a lot more information than readers wanted to know”
    You’re angling for a compliment, so you’ll get it. No. I never can get more information than I want to know. Just like on your old site this series was excellent. I teach on a much lower level than you do, but I’m experienced after some 20 years and I can judge that you have done an excellent job. After the fifth article or so the level became too high for me that I could sensibly comment, but I could easily understand every single one of them (reproducing is another matter).
    So I finish with a genuine threat. If you don’t do such an awesome series once a year I’ll never forgive you. I’d rather prefer twice a year, but let me not ask too much.

  3. 3
    filethirteen

    Excellent series Mano, and if you do turn it into a book I’ll buy it.

  4. 4
    Mano Singham

    Thanks! I may self-publish it, since that would be easy to do and it would be cheap.

  5. 5
    Marshall

    Mano, I just wanted to thank you for this wonderful series. I learned a lot more than I had hoped for!

  6. 6
    Jim B

    I had bookmarked this series back when it was starting, but I didn’t want to read it in dribs and drabs. I just came back and read it all in two evenings. Great work, Mano! This is just the right level of detail for me.

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