Brout, Englert1, Higgs2 and a few others, there cancels the huge corrections, and predicts is a fatal flaw in the standard model: it predicts a host of new particles to be discovered. We that particles are massless, in clear contradic- therefore await the restart of experiments at the tion to measurements. The mechanism that LHC in 2015 with bated breath. the researchers invented was the missing piece in a jigsaw puzzle, and the experimenE X P E R I M E N TA L E N D O R S E M E N T tal detection of the Higgs boson at the Large by Jonathan Butterworth Hadron Collider (LHC) at CERN, near Geneva, Switzerland, demonstrated that their ideas he first meeting to discuss what would were correct. François Englert and Peter W. Higgs were become the LHC took place in 1984 in As is often the case with scientific discoverawarded the Nobel Prize in Physics for ies, this completed puzzle forms just one piece Lausanne, Switzerland. The 27-kilometre the theoretical discovery of a mechanism of a still larger one concerning quantum cor- tunnel that now houses it was built for a previthat others, bestows mass on particlesparticlesrections ous to the Higgs-boson mass that occur and Higgs, among to explain thefundamental masses of fundamental involves the Higgs energy field and its associated particle, theaccelerator, the Large Electron–Positron (see figure). on an explanation1 by David J. Miller of University College London, goesatlike this: energy scales. All particles receive collider, which ran from 1989 to 2000. But as high rmly spread physicists chatting with their fellows. The room is like space quantum filled with the Higgs field. to their masses from a a result of even earlier discussions, the tunnel corrections of admirers, who increase her resistance to movement. Put another way, she acquires mass — much like a particle acquires mass by boiling sea of other particles that pop in and was built as large as possible to allow for future st, passing through out of existence, but normally the correc- options3. These included later installation of T H E the T Rroom. IUMPH OF A THEORY ur, creating a moving disturbance that is analogous to the Higgs boson. tions are small and unproblematic. But for the a hadron collider, which became the LHC. In by Ben Allanach Higgs boson, we have several corrections that the 1990s, when researchers conceived the are billions upon billions of times heavier than LHC’s ATLAS and CMS particle detectors, he proposal of the mass-giving mechanism its measured mass (about 126 times the mass with one of their major goals being to search was a coup for theoretical physics, and will of a proton). So either quantum theory, which for the Higgs boson, the required technology remain a landmark for centuries to come. The works so well in other contexts, is wrong, or we did not exist. A lengthy research and development programme was instigated to make standard model of particle physics success- are missing a jigsaw piece. fully predicts a panoply of experimental data, There are exciting ideas for the missing piece sure that, when the time came, they could some of them extremely precise, in very dif- that could solve this problem. One prominent be built. Thousands of people have worked ferent contexts. Without the ideas of Robert idea, called supersymmetry, mathematically on them. These are just examples of the kind of long-term vision and investment needed to — using particle physicist David Miller’s The mechanism proposed by Englert, Brout (deceased) and Higgs, among others, to explain the masses of fundamental particles involves the Higgs energy field and its associated particle, the Higgs boson. A rough analogy4 — set off a rumour powerful enough analogy of the mechanism, based on an explanation by David J. Miller, goes like this: to be heard. In the end, the result of this endeavour is 1. A well-known scientist walks into a room full of 2. As he moves across the room, he attracts a simple5,6. In a subset of recorded collisions uniformly spread physicists chatting with their fellows. ‘mass’ of admirers, much like a particle acquires between protons, there is a bump in the mass The room is like space filled with the Higgs field. mass by moving through the Higgs field. spectrum of pairs of photons and in the mass spectrum of four leptons (electrons and/or muons). That is the sign that we have managed to hit the background energy field of the Universe hard enough to make a wave in it. That wave is the Higgs boson. Many beautiful theoretical ideas have been proposed but consigned to oblivion, because they don’t correspond to how the Universe works. Not so the mass mechanism proposed by Brout, Englert, Higgs and others — the boson is there! ■


Endowing particles with mass



3. Now imagine a rumour, about the well-known scientist, passing through the room.

Ben Allanach is in the Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, UK. Jonathan Butterworth is in the Department of Physics and Astronomy, University College London, London WC1E 6BT, UK. e-mails: [email protected]; [email protected]

4. The physicists will gather together to hear the rumour, creating a moving disturbance that is analogous to the Higgs boson.

1. Englert, F. & Brout, R. Phys. Rev. Lett. 13, 321–323 (1964). 2. Higgs, P. W. Phys. Rev. Lett. 13, 508–509 (1964). 3. LEP design report. CERN-LEP-84-01 (CERN, 1984). 4. 5. The ATLAS Collaboration. Phys. Lett. B 716, 1–29 (2012). 6. The CMS Collaboration. Phys. Lett. B 716, 30–61 (2012). 5 D E C E M B E R 2 0 1 3 | VO L 5 0 4 | NAT U R E | 9 9

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Nobel 2013 Physics: Endowing particles with mass.

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