# CERN Finds Strong Evidence That Z Bosons Get Quantum Entangled in Higgs Decays

*2026-09-24 02:01 UTC · Science · 1 min read*

> ATLAS and CMS at CERN found 4.7-sigma evidence that Z boson pairs from Higgs boson decays are quantum entangled, the heaviest and shortest-lived particles yet tested this way.

Physicists at CERN's Large Hadron Collider have found strong evidence that pairs of Z bosons become quantum entangled when produced by a decaying Higgs boson. Both the ATLAS and CMS experiments independently reached the same conclusion using data from the LHC's second and third operational runs.

Z bosons, which carry the weak nuclear force, are unstable and vanish almost instantly, so researchers tracked them indirectly through their decay into pairs of electrons or muons. Because a Higgs boson has zero spin, the two Z bosons it produces must have spin states that sum to zero, a constraint that let scientists test for entanglement between particles far heavier and shorter-lived than any studied this way before.

The most sensitive test found the entangled state favored over the non-entangled alternative at 4.7 sigma, just short of the 5-sigma threshold physicists require to call something a confirmed discovery. The result builds on earlier entanglement evidence in top quarks and shows the Higgs boson can serve as a tool for probing quantum effects at extreme energies, with more data expected from the upcoming High-Luminosity LHC upgrade.

## Sources

- [home.cern](https://home.cern/strong-evidence-for-quantum-entanglement-between-z-bosons-found-by-atlas-and-cms/)
- [sciencealert.com](https://www.sciencealert.com/cern-detects-quantum-entanglement-in-particles-born-from-the-higgs-boson)

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TechTools News · https://techtools.cz/tools/news/article/2428-cern-finds-strong-evidence-that-z-bosons-get-quantum-entangled-in-higgs-decays
Česká verze: https://techtools.cz/tools/news/clanek/2501-cern-nasel-silne-dukazy-ze-z-bosony-se-pri-rozpadu-higgsova-bosonu-kvantove