particle physics

Everything with mass sits in this hat.

The Higgs field lives in the brim, not the middle. Tap a button to disturb it.

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drag sideways to spin · scroll for more
New since you last looked The Higgs now shows up at 5.7σ in real data.

“Find the Higgs” was a 2.4σ hint from one year of public data. It now also runs on ATLAS’s larger 2015–2016 release (36 fb⁻¹, 212,877 photon pairs), and the bump at 125 GeV crosses the 5σ line physicists use for a discovery. The analysis was frozen before any mass was computed. Statistical uncertainty only; the page says so.

See it happen →
01 · smash protons

Making two Higgs at once is absurdly rare.

Each tap is one proton–proton collision in a detector like ATLAS, seen end-on. Almost all of them are ordinary sprays of particles. The one physicists hunt for is two Higgs bosons at once.

tap Collide
Chance any one collision makes a Higgs pair: about 1 in 2.6 trillion.

While you've had this page open, an LHC running at full intensity would have made:

0collisions
0Higgs bosons
0.0000Higgs pairs (one every ~27 min)
02 · why anyone cares

The pair rate measures the hat itself.

Two diagrams make a pair: a box (a top-quark loop) and a triangle, where one Higgs splits in two. Only the triangle depends on the self-coupling κλ, and the two cancel, so the rate is lowest near κλ ≈ 2.3, not at 0. This slider is linked to the one on the hat.

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allowed by LHC data
30.8 fbpair rate at 13 TeV
≈ 4,310pairs made in Run 2 (140 fb⁻¹)
−0.71 … 6.1κλ still allowed (95% CL, ATLAS+CMS 2026)
1.1σevidence so far; discovery needs 5σ
03 · open questions

Things this page can't tell you.

  1. Is our vacuum truly the bottom of the hat, or only a long-lived dip (metastable)?
  2. Why cancel near 2.3: does that make a bigger or a smaller self-coupling easier to catch?
  3. Can single-Higgs measurements pin κλ down before pairs are ever seen?
  4. Did the hat's shape decide how the early universe cooled into this one?

Want real data? Find the Higgs yourself in actual ATLAS collisions from 2016.

Ask a particle physicist. They love this one. The first, more detailed version of this page is at /higgs/lab/.