Two photons: 5.7σ at 125 GeV from 212,877 pairs, statistics only (≈5.2σ global, allowing for a search across 118–132 GeV). Four leptons: ATLAS finds a peak at 124.55 GeV, the golden channel, and there is a CMS view to switch to. And one about your pairs: when the LHC should finally see two at once.
Two photons → Four leptons → Higgs pairs →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.
While you've had this page open, an LHC running at full intensity would have made:
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 interfere destructively, so the rate is lowest near κλ ≈ 2.3, not at 0. This slider is linked to the one on the hat.
Things this page can't tell you.
- Is our vacuum truly the bottom of the hat, or only a long-lived dip (metastable)?
- Why cancel near 2.3: does that make a bigger or a smaller self-coupling easier to catch?
- Can single-Higgs measurements pin κλ down before pairs are ever seen?
- 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 2015–2016.
Ask a particle physicist. They love this one. The first, more detailed version of this page is the κλ lab.
Where I got stuck.
- Plot twist.Every real event on this site is ATLAS data. If that’s the wrong detector, I can switch sides.
- Your channel.bbγγ, bbττ, 4b? I’m not going to guess. Okay, I’d guess bbγγ.
- Is my hat lying?Past κλ ≈ 1.25 it swears the universe is doomed. The LHC allows up to 6.1. I suspect the hat.
- My 5.7σ has zero systematics.Be honest: how much would you take off?
- 36 fb⁻¹ of public data holds about 3 bbγγ pairs.Is that an upper limit or a cry for help?
- Four leptons: done.Next view: the Z₁–Z₂ plane or the angles? You pick.
- Your favourite plot.The one you wish everyone at dinner understood.