Science › Fields & particles
The Higgs field and boson (2012)
2012· Discovery / experiment
ProvenTested many times; part of working physics.
A field filling all space that gives fundamental particles their mass; its ripple, the Higgs boson, was found at CERN in 2012.
See it on the Science map →How it works
Proposed in 1964 by Peter Higgs and, independently, François Englert with Robert Brout and a third group. Particles gain mass in proportion to how strongly they interact with this field. The W and Z carriers gain mass this way, as do electrons and quarks. Without it, electrons would be massless and atoms could not form. Most of your body's mass, however, comes from the strong force inside protons, not directly from the Higgs.
Why it matters
It completed the Standard Model and was the first fundamental field of its kind ever found, a field with no direction, only a strength.
How we know
Discovered on July 4, 2012, by the ATLAS and CMS experiments at the Large Hadron Collider, at about 133 times a proton's mass. Nobel Prize 2013 to Englert and Higgs.
Still a mystery
Why is the Higgs so light compared with what quantum effects would suggest? And our vacuum may be only temporarily stable.
Connections (5)
▸The Higgs field and boson (2012) completes The Standard ModelProven
The relationship
Without the Higgs field, the W and Z bosons, electrons and quarks would all be massless, and the theory's predictions would break down at high energies, giving probabilities above 100%. The Higgs field fixes both problems. It was the last predicted particle of the Standard Model to be found, completing the set.
How the link was found
Proposed in 1964 by Peter Higgs, by François Englert with Robert Brout, and by Guralnik, Hagen and Kibble. Weinberg built it into the electroweak theory in 1967.
Why it's proven
Found in 2012 at the Large Hadron Collider. Its measured interactions with other particles so far agree with predictions.
Open questions and mysteries
Why the particles' interactions with the Higgs, and so their masses, have the values they do is not explained.
▸The Higgs field and boson (2012) leaves ~99% of proton mass to E = mc²Proven
The relationship
The Higgs field gives electrons and quarks their mass. But the three quarks inside a proton account for only about 1% of its mass. The rest is the energy of quarks moving near light speed and the gluon field binding them, which counts as mass through E = mc². Most of the weight of ordinary matter is bound-up energy.
How the link was found
Worked out through quantum chromodynamics, the theory of the strong force, developed in the 1970s. Supercomputer lattice calculations computed the proton's mass from it in 2008.
Why it's proven
The 2008 lattice calculations (Dürr and colleagues) reproduced the proton and neutron masses within a few percent using only quark properties and the strong force.
Open questions and mysteries
Proving mathematically why quarks stay permanently trapped inside protons is tied to an unsolved Millennium Prize problem, the Yang-Mills mass gap.
▸The Higgs field and boson (2012) explains the short reach of The weak force and radioactivityProven
The relationship
The weak force's carriers, the W and Z bosons, gain large masses, about 85 and 97 times a proton, by interacting with the Higgs field. Heavy carriers can only travel a tiny distance before vanishing, so the weak force reaches only about a thousandth of a proton's width. The photon ignores the Higgs, stays massless, and so electromagnetism reaches across the universe.
How the link was found
Built into the electroweak theory by Steven Weinberg in 1967 and Abdus Salam in 1968, using the 1964 Higgs mechanism.
Why it's proven
The theory predicted the W and Z masses before their 1983 discovery. The Higgs boson's measured coupling to W and Z, since 2012, matches.
Open questions and mysteries
Why the Higgs field settled at the strength it did, setting the W and Z masses, is unexplained.
▸The Higgs field and boson (2012) may sit in a false vacuum, risking Vacuum decay and bubbles of new spaceWell supported
The relationship
The Higgs field's energy hill is reshaped by quantum effects of the particles it touches, above all the heavy top quark. With the measured Higgs mass, about 125 GeV, the calculated hill turns downward at extreme field strengths, around 10¹⁰ GeV and beyond, revealing a deeper valley. Our vacuum would then be false but extremely long-lived: metastable.
How the link was found
Soon after the 2012 discovery, precise calculations by Giuseppe Degrassi, Alessandro Strumia and colleagues (2012–13) placed our vacuum in the metastable zone, close to the border with stable.
Is it proven?
The inputs are measured: a top quark under 1% lighter would make the vacuum stable. One 2018 estimate puts the lifetime near 10¹⁶¹ years. Cosmic rays outdo colliders, so colliders pose no risk (Hut and Rees, 1983).
Open questions and mysteries
It assumes no unknown particles up to enormous energies; new physics could stabilize it. Why nature sits so near the stable–unstable border, and how our vacuum survived the hot early universe, are open.
▸The Higgs field and boson (2012) switches on in The Higgs switches on (electroweak epoch)Proven
The relationship
Heat reshapes the Higgs field's energy curve. In the hot plasma, particles that feel the field add energy that is lowest when the field is zero, so it sat at zero. Below about 2×10¹⁵ degrees (160 GeV) that extra energy faded, zero became a hump, and the field slid into the surrounding valley: gradually, like a dimmer, not a switch.
How the link was found
David Kirzhnits and Andrei Linde (1972) showed heat would switch the Higgs field off. Kajantie, Laine, Rummukainen and Shaposhnikov showed by computer in 1996 that for a heavy Higgs the change is smooth.
Why it's proven
The Higgs field and its 125 GeV mass are measured (2012). The high-temperature behavior is calculated, not observed, but rests on well-tested theory.
Open questions and mysteries
The Higgs field's interaction with itself, which shapes its energy curve, is barely measured. If it differs from prediction, the switch-on may have been sharp. The High-Luminosity LHC, from about 2030, aims to measure it.