Note: We view the chapter notes as a study guide to the subject of particle physics and related sciences. Particle physics was the origin of the World Wide Web, and today the Web, and also Wikipedia, have become the most readily accessible, up-to-date, and reasonably reliable sources of information about the sciences. We have therefore provided many references, without apology, to related Wikipedia articles, and we urge the reader to seek out additional sources that are referred to within these articles.
CHAPTER 1. INTRODUCTION
1. We recommend an excellent account of the remarkable story of modern economics: David Warsh, Knowledge and the Wealth of Nations: A Story of Economic Discovery (W. W. Norton & Company, 2007). We thank our distinguished colleague, Dr. Richard Vidal, for bringing this to our attention.
2. See “Tim Berners-Lee,” http://en.wikipedia.org/wiki/Tim_Berners-Lee; Berners-Lee and his associates, who helped design the Internet protocols and early browser, Robert Kahn, Vinton Cerf, Marc Andreessen, and Louis Pouzin, recently received the inaugural Queen Elizabeth Prize for Engineering ($1.5 million each), http://blogs.wsj.com/tech-europe/2013/03/18/berners-lee-wins-1-million-engineering-prize/. See also “Mosaic” (web browser), http://en.wikipedia.org/wiki/Mosaic_browser (sites last visited 3/20/2013).
3. Al Gore's contribution was to create and pass legislation called the “High-Performance Computing and Information Act of 1991” (also called the “Gore Act”) to free up and use government-funded networks of computers, known as ARPANET, to the people. The World Wide Web really began as a combination of Berners-Lee's software and the ARPANET hardware. The Gore contribution to the Internet can be found on the Internet: http://en.wikipedia.org/wiki/Al_Gore_and_information_technology; see also “ARPANET,” http://en.wikipedia.org/wiki/ARPANET (sites last visited 3/1/2013).
4. Here are some references on the SSC and its demise: “Lots of Reasons, but Few Lessons,” http://www.sciencemag.org/content/302/5642/38.full; see “SSC,” http://en.wikipedia.org/wiki/Superconducting_Super_Collider; “How Close Was the Vote to Cancel the Superconducting Super Collider?” http://www.quora.com/How-close-was-the-vote-to-cancel-the-Superconducting-Super-Collider (sites last visited 3/8/2013). Quoting from the latter source,
The House of Representatives voted three times in 1992 and 1993 to kill the SSC; the final pivotal vote was 159–264 (139 Cong. Rec. H8124 (daily ed. Oct. 19, 1993)). The Senate voted to rescue it each time; their last vote in favor was 57–42 (139 Cong. Rec. S12,760 (daily ed. Sept. 30, 1993)). In 1993, the two houses met in a conference committee twice; the first time the Senate negotiators won and the SSC was left in the bill. The second time the House won. In the end the conference report was adopted by both houses with large majorities: 332–81 in the House, 139 Congressional Record H8435 (daily ed. Oct. 26, 1993), and 89–11 in the Senate, 139 Congressional Record S14483 (daily ed. Oct. 27, 1993).
5. See the historical website of CERN: http://public.web.cern.ch/public/en/about/History-en.html (site last visited 3/1/2013). Quoting from this source:
CERN is run by 20 European Member States, but many non-European countries are also involved in different ways. Scientists come from around the world to use CERN's facilities. The current Member States are: Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, the Slovak Republic, Spain, Sweden, Switzerland and the United Kingdom. Romania, Israel and Serbia are candidates to become Member States of CERN. Member States have special duties and privileges. They make a contribution to the capital and operating costs of CERN's programmes, and are represented in the Council, responsible for all important decisions about the Organization and its activities.
Some states (or international organizations) for which membership is either not possible or not yet feasible are Observers. “Observer” status allows non-Member States to attend Council meetings and to receive Council documents, without taking part in the decision-making procedures of the Organization. Scientists from institutes and universities around the world use CERN's facilities. Physicists and their funding agencies from both Member and non-Member States are responsible for the financing, construction and operation of the experiments on which they collaborate. CERN spends much of its budget on building new machines (such as the Large Hadron Collider), and it only partially contributes to the cost of the experiments. Observer States and Organizations currently involved in CERN programs are: the European Commission, India, Japan, the Russian Federation, Turkey, UNESCO and the USA. Non-Member States with co-operation agreements with CERN are: Algeria, Argentina, Armenia, Australia, Azerbaijan, Belarus, Bolivia, Brazil, Canada, Chile, China, Colombia, Croatia, Cyprus, Ecuador, Egypt, Estonia, Former Yugoslav Republic of Macedonia (FYROM), Georgia, Iceland, Iran, Jordan, Korea, Lithuania, Malta, Mexico, Montenegro, Morocco, New Zealand, Pakistan, Peru, Saudi Arabia, Slovenia, South Africa, Ukraine, United Arab Emirates and Vietnam. CERN also has scientific contacts with: China (Taipei), Cuba, Ghana, Ireland, Latvia, Lebanon, Madagascar, Malaysia, Mozambique, Palestinian Authority, Philippines, Qatar, Rwanda, Singapore, Sri Lanka, Thailand, Tunisia, Uzbekistan and Venezuela.
Further information about CERN's international relations can be found at http://cern.ch/international-relations (site last visited 3/8/2013).
6. The Tevatron was a proton–antiproton collider. The antiproton is the “antiparticle” of the proton, and these have to be made at the laboratory, stored, “cooled,” and re-injected into the machine to make collisions; see “Tevatron,” http://en.wikipedia.org/wiki/Tevatron (site last visited 3/8/2013) and chapter 9.
7. See “LEP,” http://en.wikipedia.org/wiki/LEP (site last visited 3/8/2013) and chapter 9.
8. The LHC experiments are discussed in further detail with many beautiful photographs at http://public.web.cern.ch/public/en/LHC/LHCExperiments-en.html (site last visited 3/7/2013). The ATLAS experiment is further discussed here: http://public.web.cern.ch/public/en/LHC/ATLAS-en.html (site last visited 3/7/2013). Quoting from the source:
ATLAS is one of two general-purpose detectors at the LHC. It will investigate a wide range of physics, including the search for the Higgs boson, extra dimensions, and particles that could make up dark matter. ATLAS will record sets of measurements on the particles created in collisions—their paths, energies, and their identities. This is accomplished in ATLAS through six different detecting subsystems that identify particles and measure their momentum and energy. Another vital element of ATLAS is the huge magnet system that bends the paths of charged particles for momentum measurement. More than 2900 scientists from 172 institutes in 37 countries work on the ATLAS experiment (December 2009).
The CMS experiment is further discussed here: http://public.web.cern.ch/public/en/LHC/CMS-en.html (site last visited 3/7/2013). Quoting from this source:
The CMS experiment uses a general-purpose detector to investigate a wide range of physics, including the search for the Higgs boson, extra dimensions, and particles that could make up dark matter. Although it has the same scientific goals as the ATLAS experiment, it uses different technical solutions and design of its detector magnet system to achieve these. The CMS detector is built around a huge solenoid magnet. This takes the form of a cylindrical coil of superconducting cable that generates a magnetic field of 4 teslas, about 100,000 times that of the Earth. The magnetic field is confined by a steel “yoke” that forms the bulk of the detector's weight of 12,500 tonnes. An unusual feature of the CMS detector is that instead of being built in-situ underground, like the other giant detectors of the LHC experiments, it was constructed on the surface, before being lowered underground in 15 sections and reassembled. More than 2000 scientists collaborate in CMS, coming from 155 institutes in 37 countries (October 2006).
9. See “LHC Magnet Types,” http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach/components/magnets/types_of_magnets.htm (site last visited 3/7/2013).
10. See “Magnet quench,” http://en.wikipedia.org/wiki/Magnet_qu
ench#Magnet_quench (site last visited 3/8/2013).
11. This is a heroic story and only attests to the profound success of the LHC project, yet it's hard to find a comprehensive historical record that captures the drama and intensity of this event. See “Large Hadron Collider,” http://en.wikipedia.org/wiki/Large_Hadron_Collider (site last visited 3/7/2013). Quoting from this source:
Problems occurred on 19 September 2008 during powering tests of the main dipole circuit, when an electrical fault in the bus between magnets caused a rupture and a leak of six tonnes of liquid helium. The operation was delayed for several months. It is currently believed that a faulty electrical connection between two magnets caused an arc, which compromised the liquid-helium containment. Once the cooling layer was broken, the helium flooded the surrounding vacuum layer with sufficient force to break 10-ton magnets from their mountings. The explosion also contaminated the proton tubes with soot. This accident was thoroughly discussed in a 22 February 2010 Superconductor Science and Technology article by CERN physicist Lucio Rossi.
See also BBC News: http://news.bbc.co.uk/2/hi/in_depth/7632408.stm; Daily Mail online: http://www.dailymail.co.uk/sciencetech/article-1256966/Large-Hadron-Collider-Cern-finally-reach-power-2013—years-schedule.html#axzz2JfKcqlSt (sites last visited 3/8/2013).
12. This is more properly known as the “Englert-Brout-Higgs-Guralnik-Hagen-Kibble Mechanism,” after its many contemporaneous co-inventors: http://en.wikipedia.org/wiki/Robert_Brout, http://en.wikipedia.org/wiki/Fran%C3%A7ois_Englert, http://en.wikipedia.org/wiki/Gerald_Guralnik; http://en.wikipedia.org/wiki/C._R._Hagen, http://en.wikipedia.org/wiki/Peter_Higgs, http://en.wikipedia.org/wiki/Tom_W._B._Kibble (sites last visited 3/7/2013).
13. See “London equations,” the first theory of superconductivity in 1935, http://en.wikipedia.org/wiki/London_theory. The theory was proposed by brothers Fritz and Heinz London, though subsequent theoretical refinements containing the germ of the Higgs mechanism were due to Fritz London: http://en.wikipedia.org/wiki/Fritz_London. This is further generalized in the Ginzburg–Landau Theory of Superconductivity, in 1950: http://en.wikipedia.org/wiki/Ginzburg%E2%80%93Landau_theory. This is essentially a forerunner of the Higgs boson theory with the famous “Higgs potential” (sites last visited 3/8/2013).
14. See “Steven Weinberg,” http://en.wikipedia.org/wiki/Steven_weinberg; “A Model of Leptons,” Phys. Rev. Lett. 19, nos. 1264–66 (1967) was based upon Sheldon Glashow, “Partial Symmetries of the Weak Interactions,” Nucl. Phys. 22, no. 579 (1961). This marks the beginning of the modern Standard Model era of particle physics. In Steven Weinberg, “The Crisis of Big Science,” New York Times Book Review (2012), http://www.nybooks.com/articles/archives/2012/may/10/crisis-big-science/ (sites last visited 3/8/2013). Weinberg comments:
In his recent book, The Infinity Puzzle (Basic Books, 2011), Frank Close points out that a mistake of mine was in part responsible for the term “Higgs boson.” In my 1967 paper on the unification of weak and electromagnetic forces, I cited 1964 work by Peter Higgs and two other sets of theorists. This was because they had all explored the mathematics of symmetry-breaking in general theories with force-carrying particles, though they did not apply it to weak and electromagnetic forces. As known since 1961, a typical consequence of theories of symmetry-breaking is the appearance of new particles, as a sort of debris. A specific particle of this general class was predicted in my 1967 paper; this is the Higgs boson now being sought at the LHC.
As to my responsibility for the name “Higgs boson,” because of a mistake in reading the dates on these three earlier papers, I thought that the earliest was the one by Higgs, so in my 1967 paper I cited Higgs first, and have done so since then. Other physicists apparently have followed my lead. But as Close points out, the earliest paper of the three I cited was actually the one by Robert Brout and François Englert. In extenuation of my mistake, I should note that Higgs and Brout and Englert did their work independently and at about the same time, as also did the third group (Gerald Guralnik, C.R. Hagen, and Tom Kibble). But the name “Higgs boson” seems to have stuck.
15. See “Higgs boson,” http://en.wikipedia.org/wiki/Higgs_boson (site last visited 3/8/2013).
16. Leon M. Lederman and Dick Teresi, The God Particle: If the Universe Is the Answer, What Is the Question? (Mariner Books, 2006); see also http://en.wikipedia.org/wiki/The_God_Particle:_If_the_Universe_Is_the_Answer,_What_Is_the_Question%3F (site last visited 4/8/2013).
CHAPTER 2. A BRIEF HISTORY OF THE BIG QUESTIONS
1. See “Democritus,” http://en.wikipedia.org/wiki/Democritus; see also “Classical element” and references therein, http://en.wikipedia.org/wiki/Classical_element (sites last visited 3/8/2013).
2. Chemists write this as a chemical reaction: CH4 + 2O2 → CO2 + 2H2O, which translates into “one methane (CH4) and two oxygen molecules (2O2) react to make one carbon dioxide (CO2) and two water molecules (2H2O).” Note that the total number of oxygen atoms on the left side of the reaction is 2 × 2 = 4, since there are two O2 molecules, each containing two O atoms; the total afterward is 2 + 2 = 4, since 2 O atoms enter the CO2 molecule and two O atoms are present in the two water molecules.
3. See our book Quantum Physics for Poets (Amherst, NY: Prometheus Books, 2010).
4. See “Energy,” http://en.wikipedia.org/wiki/Energy, “Electron volt,” http://en.wikipedia.org/wiki/Electronvolt (sites last visited, 4/2/2013).
In discussing atoms and subatomic things, we use a very tiny quantity of energy, the electron volt, or eV. One electron volt is the energy that a one-volt battery expends pushing a single electron (the fundamental particle that orbits all atoms) through an electric circuit.
Most biological chemical reactions involve delicate, weaker chemical bonds, usually less than an electron volt per bond. Much of the entire stratum of biological processes is in the smaller energy range, around 0.1 eV. In contrast, the explosion of acetylene gas with oxygen liberates the energy of a triple carbon chemical bond—about 10 eV per acetylene molecule, and that is found to make a very loud bang—a shock wave in the surrounding air due to the release of chemical energy in the kinetic form. Indeed, high explosives such as TNT or fracking explosives can contain even higher energy bonds. Thus, around 10 eV, we enter the stratum of high-energy chemistry. By contrast, a proton and neutron can form a “deuteron,” which is the simplest compound nucleus, the nucleus of deuterium, or “heavy hydrogen,” and the energy released by this nuclear binding is about 2.23 MeV (million eV); this is a small nuclear binding energy. See http://en.wikipedia.org/wiki/Deuterium (site last visited 4/2/2013).
The conversion to larger energy units used in everyday engineering and macrophysics shows just how tiny this is. In the meter-kilogram-second system (mks), we use the energy unit “joule,” which is one watt of power for one second. A 60-watt light is consuming 60 joules of energy per second. This is the electrical power (energy per time) consumed by the lightbulb. An automobile driving down the road at 50 mph typically has a kinetic energy (energy of motion) of 450,000 joules.
The conversion of joules to eV is 1 joule = 6.24150974 × 1018 eV. (That's approximately 6 followed by eighteen zeros.) The electron volt is a tiny unit of energy more appropriate for single atoms or particles, while joules are used for large macroscopic assemblages of atoms, such as mechanical engineering or electrical power applications.
Einstein's famous formula E = mc2 implies that any particle at rest has an energy, E, that is equivalent to its inertial mass, m. We can therefore use energy units to quantify an elementary particle's mass. For example, the proton mass, which is 1.67262158 × 10-27 kilograms, can be restated in terms of electron volts, using the conversion 1 GeV/c2 = 1.783 × 10−27 kg, so a proton mass is 0.938 GeV/c2 (1 GeV = 1 billion eV; 1 MeV = one million eV).
We'll often drop the “/c2” and make a rough approximation, taking the proton and neutron masses to be approximately 1 GeV/c2, abbreviated to 1 GeV. The electron mass, likewise, is 0.511 MeV/c2, abbreviated to 0.5 MeV.
6. See “J. J. Thompson” and references therein, http://en.wikipedia.org/wiki/J._J._Thomson (site last visited 3/10/13).
7. See “Ernest Rutherford,” http://en.wikipedia.org/wiki/Ernest_Rutherford (site last visited 3/10/13). “Good with his hands (unlike his mentor J.J. Thompson) and contemptuous of the head-in-the-clouds theoretical physicists, Rutherford was famous amongst his post-docs for acerbic quotes like the following: ‘Oh, that stuff (Einstein's relativity). We never bother with that in our work,’” quoted in David Wilson, Rutherford. Simple Genius (Hodder & Stoughton, 1983); Richard Reeves, A Force of Nature: The Frontier Genius of Ernest Rutherford (New York: W. W. Norton, 2008).
8. Ibid.
9. Ibid.
10. Jan Faye, Niels Bohr: His Heritage and Legacy (Dordrecht: Kluwer Academic Publishers, 1991). See “Niels Bohr,” http://en.wikipedia.org/wiki/Niels_Bohr (site last visited 3/10/13).
11. See “Cosmic ray,” http://en.wikipedia.org/wiki/Cosmic_ray (site last visited 4/2/2013).
12. See “Nuclear physics,” http://en.wikipedia.org/wiki/Nuclear_physics, “Atomic nucleus,” http://en.wikipedia.org/wiki/Atomic_nucleus, “Protons,” http://en.wikipedia.org/wiki/Proton, “Neutrons,” http://en.wikipedia.org/wiki/Neutron. These are generically called “nucleons,” http://en.wikipedia.org/wiki/Nucleons. All atoms are characterized by the number of protons in their nucleus, or their “atomic number,” http://en.wikipedia.org/wiki/Atomic_number. The number of neutrons can vary, from zero for hydrogen, to well over 150 for heavy unstable atoms, etc. For a fixed number of protons, the number of neutrons can vary, leading to “isotopes,” http://en.wikipedia.org/wiki/Isotopes (all sites last visited 3/10/13).
Beyond the God Particle Page 30