Professor Emeritus at the University of Edinburgh, Edinburgh, United Kingdom.
A Brief History of the Higgs Mechanism: The scientific work behind the Higgs boson
The electroweak theory, which unifies the electromagnetic and weak interactions of elementary particles, has, since 1970, received experimental support to a precision unprecedented in the history of science. This unification involves a close relationship between the massless photon, which carries the long-range electromagnetic force, and the W and Z vector bosons, which carry the short-range weak force and must therefore be very massive. Prior to the invention of the Higgs mechanism, it was not known how to formulate a consistent relativistic field theory with a local symmetry which could contain both massless and massive force carriers.
In 1962, Goldstone’s theorem had shown that spontaneous breaking of symmetry in a relativistic field theory results in massless spin-zero bosons, which are excluded experimentally. In a paper published in Physics Letters on 15 September 1964 (received on 27 July 1964), Peter Higgs showed that Goldstone bosons need not occur when a local symmetry is spontaneously broken in a relativistic theory. Instead, the Goldstone mode provides the third polarisation of a massive vector field. The other mode of the original scalar doublet remains as a massive spin-zero particle – the Higgs boson.
Higgs wrote a second short paper describing what came to be called “the Higgs model” and submitted it to Physics Letters, but it was rejected on the grounds that it did not warrant rapid publication. Higgs revised the paper and submitted it to Physical Review Letters, where it was accepted, but the referee, who turned out to be Yoichiro Nambu, asked Higgs to comment on the relation of his work to that of Francois Englert and Robert Brout, which was published in Physical Review Letters on 31 August 1964, the same day his paper was received. Higgs had been unaware of their work, because the Brussels group did not send preprints to Edinburgh. Higgs’ revised paper drew attention to the possibility of a massive spin-zero boson in its final paragraph. During October 1964, Higgs had discussions with Gerald Guralnik, Carl Hagen and Tom Kibble, who had discovered how the mass of non-interacting vector bosons can be generated by the Anderson mechanism.
The previous year, Philip Anderson had pointed out that, in a superconductor where the local gauge symmetry is broken spontaneously, the Goldstone (plasmon) mode becomes massive due to the gauge field interaction, whereas the electromagnetic modes are massive (Meissner effect) despite the gauge invariance. However, he did not discuss any relativistic model and so, since Lorentz invariance was a crucial ingredient of the Goldstone theorem, he did not demonstrate that it could be evaded. In Higgs’ second 1964 paper (2) he referred to Anderson’s work in a way which implied that Anderson knew about the non-relativistic counterpart of the Higgs boson. In fact, Anderson didn’t and it was not until 1981 that an unexpected feature of the Raman spectrum of NbSe2 was understood to be due to “a massive collective mode which exists in all superconductors – the oscillation of the amplitude of the superconducting gap”, the only Higgs boson to be discovered experimentally before 2012.
The search for the Higgs boson became a major objective of experimental particle physics. Although the best fit to all the electroweak precision measurements gave its mass between 52 and 110 GeV, it was excluded below 114 GeV. Its mass could not exceed 1 TeV if the electroweak theory itself is to remain valid up to this energy scale, precisely the range that is within reach CERN’s Large Hadron Collider. We know now that the ATLAS and CMS have found a Higgs-like boson at a mass of around 126 GeV which increasingly looks like having all the properties of the Standard Model Higgs boson.
Peter Higgs’ work was a crucial step on the road to a unified theory of the forces of Nature and is clearly basis for an experimental programme to look at further details of the discovered particle and its extensions beyond the Standard Model.
2013 Nobel Prize in Physics, jointly with François Englert, \\\\\\\\\\\\\\\"for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN\\\\\\\\\\\\\\\'s Large Hadron Collider\\\\\\\\\\\\\\\"
Peter Higgs’ contribution to physics has been recognised by numerous academic honours: the Hughes Medal of the Royal Society (1981, shared with Tom Kibble), the Rutherford Medal of the Institute of Physics (1984, also shared with Tom Kibble), the Saltire Society & Royal Bank of Scotland Scottish Science Award (1990), the Royal Society of Edinburgh James Scott Prize Lectureship (1993), the Paul Dirac Medal and Prize of the Institute of Physics (1997), and the High Energy and Particle Physics Prize of the European Physical Society (1997, shared with Robert Brout and François Englert), Royal Medal of the Royal Society of Edinburgh (2000), Wolf Prize in Physics (2004, shared with Robert Brout and François Englert), the Stockholm Academy of Sciences Oskar Klein Memorial Lectiure and Medal (2009) and the American Physical Society J J Sakurai Prize (2010), shared with Robert Brout, François Englert, Gerry Guralnik, Carl Hagen and Tom Kibble). He received a unique personal Higgs medal from the Royal Society of Edinburgh on 1 October 2012 and the 2013 Nonino Prize \'Man of Our Time\'. He shared the award of the 2013 Edinburgh International Science Festival Edinburgh Medal with CERN and the 2013 Prince of Asturias Award for Technical and Scientific Research with François Englert and CERN.
• “Theoretical Determination of Electron Density in Organic Molecules” (with C A Coulson, S L Altmann and N H March) Nature 168 1039 (1951)
• “Perturbation Method for the Calculation of Molecular Vibration Frequencies I” J. Chem. Phys. 21 1131 (1953)
• “A Method for Computing Zero-Point Energies” J. Chem. Phys. 21 1330 (1953)
• “Vibration Spectra of Helical Molecules” Proc. Roy. Soc. A220 472 (1953)
• “Vibrational Modifications of the Electron Density in Molecular Crystals I” Acta. Cryst. 6 232 (1953)
• “Perturbation Method for the Calculation of Molecular Vibration Frequencies II” J. Chem. Phys. 23 1448 (1955)
• “Perturbation Method for the Calculation of Molecular Vibration Frequencies III” J. Chem. Phys. 23 1450 (1955)
• “Vibrational Modifications of the Electron Density in Molecular Crystals II” Acta. Cryst. 8 99 (1955)
• “A Method for Calculating Thermal Vibration Amplitudes from Spectroscopic Data” Acta. Cryst. 8 619 (1955)
• “Vacuum Expectation Values as Sums over Histories” Nuovo Cimento (10) 4 1262 (1956)
• “On Four-Dimensional Isobaric Spin Formalisms” Nuclear Physics 4 1262 (1957)
• “Integration of Secondary Constraints in Quantized General Relativity” Phys. Rev. Lett. 1 373 (1958)
• “Integration of Secondary Constraints in Quantized General Relativity” Phys. Rev. Lett. 3 66 (1959)
• “Quadratic Lagrangians and General Relativity” Nuovo Cimento (10) 11 816 (1959)
• “Broken Symmetries, Massless Particles and Gauge Fields” Physics Letters 12 132 (1964)
• “Broken Symmetries and the Masses of Gauge Bosons” Phys. Rev. Letters. 13 508 (1964)
• “Spontaneous Symmetry Breakdown without Massless Bosons” Phys. Rev. 145 1156 (1966)
• “Spontaneous Symmetry Breaking” two lectures at the 14th Scottish Universities Summer School in Physics (1973). Published in “Phenomenology of Particles at High Energy” R L Crawford, R Jennings (eds.) Academic Press (1974) ISBN 9780121971502
• “Dynamical Symmetries in a Spherical Geometry I” J. Phys. A12 309 (1979)
• “SBGT and All That”, International Conference \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"50 Years of Weak Interactions from the Fermi Theory to the W\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" Wingspread, Racine, Wisconsin (29 May-1 June 1984). Published in the conference proceedings by University of Wisconsin at Madison and reproduced in AIP. Conf. Proc. 300:159-163 (1994)
• “Inventing an Elementary Particle”, INFN Eloisatron Project 9th Workshop “Higgs Particles - Physics Issues and Experimental Searches in High-energy Collisions”, Erice, Italy (15-26 Jul 1989). Published in \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"Higg(s) Particle(s): Physics Issues and Experimental Searches in High-Energy Collisions\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" A Ali (ed.) Ettore Majorana International Science Series 50 1-5 Plenum Press (1990) ISBN 9780306435898
• “Spontaneous Symmetry Breaking 25 Years Ago”, 26th International Conference on Subnuclear Physics “Physics up to 200 TeV”, Erice, Italy (16-24 Jul 1990). Published in \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"Physics up to 200TeV\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" A Zichichi (ed.) The Subnuclear Series 28 439-444 Plenum Press (1991) ISBN 9780306439353
• Panel Session “Spontaneous Breaking of Symmetry” (with L M Brown, R Brout, T Y Cao, Y Nambu) 3rd International Symposium on the History of Particle Physics “The Rise of the Standard Model” (1992): published in “The Rise of the Standard Model”, L Hoddesdon, L M Brown, M Riordan, M Dresden (eds.) Cambridge University Press, (1997) ISBN 978052157165
• “My Life as a Boson: The Story of ‘The Higgs“ Inaugural Conference of the Michagan Center for Theoretical Physics “2001 A Spacetime Odyssey” Ann Arbor, Michigan (21-25 May 2002). Published in \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"2001 A Spacetime Odyssey\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\" M J Duff, J T Liu (eds.) World Scientific (2002) ISBN 9789810248062 and reproduced in Int. J. Mod. Phys. A17S1 86-88 (2002)
• “Prehistory of the Higgs Boson” Comptes Rendus Physique 8 970-972 (2007)