20 Things You (probably) Didn’t Know About the Higgs Boson by Saul-Paul Sirag (7/7/12) 1. It’s called a boson, because it has spin-0, which puts it into the family of integral-spin particles (including the photon with spin-1). 2. All bosons obey Bose-Einstein statistical rules. Satyendranath Bose and Albert Einstein published these statistical rules in 1924. These statistics imply that bosons tend to be in the same quantum state, an example being the photons in a laser beam. 3. The other family of particles (which have half-integral spin) is called Fermions because they obey Fermi-Dirac statistical rules, published by Enrico Fermi and Paul Dirac in 1926. For example, electrons and protons have spin-1/2, and thus obey Fermi-Dirac statistics. These statistics imply that any two fermions (of like kind) can never be in the same quantum state. This is why there is solid matter. 4. It’s called the Higgs Boson, after Peter Higgs who in 1964 published a paper proposing the existence of a spin-0 field that provided mass to the spin-1 particles that carry the weak force. 5. Five other physicists, published a similar idea in two papers: (1) Francois Englert & Robert Brout, of Universite Libre de Bruxelles. (2) Tom Kibble of Imperial College, London; Gerald Guralnik of the University of Rochester; & Carl Hagen of Brown University. 6. However, Dr. Higgs (at the University of Edinburgh) was the first to propose that there had to be a massive spin-0 particle which could in principle be detected. He added this particle proposal as an extra paragraph to his paper in order to rebut the criticism that his idea was not sufficiently relevant to be published. 7. The Higgs Boson is called the last remaining item of the Standard Model of particle physics to be detected. However, by the rules of the Standard Model alone, the Higgs particle would absorb too much mass by interacting with the virtual particles of the quantum vacuum. 8. Enter SUSY (more formally called supersymmetry). SUSY requires a supersymmetry partner (of opposite-spin type) for every particle of the Standard Model. SUSY fixes the problem of too much mass from the virtual particle interactions, because supersymmetry partners have an opposite effect on the virtual interactions. 9. But wait, the discovery of a Higgs boson with a mass of 125 GeV at the Large Hadron Collider (the LHC), looks too much like a plain-vanilla Standard Model Higgs boson. 10. Well, Gordon Kane (at the University of Michigan) has a solution: bring in M-theory (which unifies the 5 competing Superstring theories, entailing also SUSY, of course). In this very avant garde (but beautiful) picture, “the lightest Higgs boson behaves very much like the standard-model Higgs boson. And it has a mass of about 125 GeV, just as observed.” (See: Gordon Kane, Nature, 16 Dec. 2011). 11. Dr. Kane says “the lightest Higgs boson” because SUSY claims that there are 4 other Higgs bosons, but they are much too massive to detected at LHC. 12. So how can we distinguish between a Standard-Model Higgs boson and a SUSY modified version of the lightest Higgs boson? Dr. Kane has a ready answer: “It will be easy to tell h [the Higgs boson] is the supersymmetric one since superpartners will also be found.” (See: http://www.science20.com/print/82028 .) 13. Incidentally, Dr. Kane has just won a $100-bet with Stephen Hawking (of Cambridge University). Dr. Hawking made a bet with Dr. Kane that the Higgs boson could not be found at the LHC (because it would be swamped the noise of mini black holes). So far, at the LHC, the Higgs has been found but the mini black holes have not shown up. 14. The Higgs boson is also called the God Particle, because that is the title of a (very funny) popular book by Leon Lederman (with Dick Teresi) in 1993. Somewhat like in the Bible, the universe started out with a chaotic mix of particles all moving at the speed of light because none of them had rest mass. Then very close to the beginning of time the Higgs field turned on and the particles wading through this field slowed down a bit because they were accumulating rest mass. 15. The name God Particle, has offended many physicists (and others). Dr. Lederman (Nobel laureate & former director of the Fermi National Accelerator Laboratory) wrote in his book that he wanted to call it “the Goddamed particle” because it is so hard to find; but his publisher (Houghton Mifflin Co.) insisted on “the God particle.” 16. There was not enough evidence at Fermilab Tevatron (with only 2TeV energy level) to claim a discovery of the Higgs boson, according to the most recent data analysis released on the 2nd of July, 2012, just 2 days before the LHC claim of Higgs boson at 125-126 GeV. 17. Dr. Lederman was the leader of the plan to build the Superconducting Supercollider (SSC) at Waxahachie, Texas, which would have had a ring 54 miles in circumference and produce collisions at 40 TeV. (Compare this to the LHC with a 27-mile ring and a top collision energy of 14 TeV.) Dr. Lederman wrote his book to drum up support in the US (especially the Congress) for building the SSC. Construction had already begun, but there was a good possibility that the whole project would be cancelled by the US Congress. 18. The very year The God Particle was published (1993), Congress did cancel the SSC. Two billion Dollars had already been spent in design of the SSC and construction of the underground tunnel. President Bill Clinton (in his first year in office) urged Congress “to support this important and challenging effort” because “abandoning the SSC at this point would signal that the United States is compromising its position of leadership in basic science.” It would have cost another 10 billion Dollars to complete the SSC by the year 2000. (Compare this with the smaller and much later LHC costing about 12 billion Dollars.) See: Superconducting Supercollider in Wikipedia. 19. Still, Lederman & Terresi’s book, The God Particle, is one of the best books (and most fun to read) to understand the discovery of the Higgs Boson at the LHC, announced at CERN on the 4th of July, 2012. 20. Also Gordon Kane’s book, Supersymmetry (Perseus, 2000) is wonderfully clear. His “Appendix B: The Supersymmetry Explanation of the Higgs Mechanism” is a must read for insight into SUSY’s role in all this.