A rare path that is easy to miss
Physicists working on the ATLAS experiment at CERN's Large Hadron Collider report evidence of the Higgs boson decaying into a virtual photon and a real photon. The process is expected in only about one in 10,000 Higgs decays, which makes it one of the hardest behaviours to catch.
Because the Higgs particle is short-lived, researchers cannot see it directly. They study the particles it leaves behind and look for patterns that match a predicted pathway.
Why the result matters
The Higgs boson is tied to how fundamental particles get mass. Measuring rare decays tests whether its interactions match the standard model of particle physics, the framework that describes known particles and forces.
If measurements drift from predictions, that can point to new particles or forces not yet seen. So far, the new result fits the expected picture, but the team says the data sample is still small.
The analysis draws on collisions recorded over several years, and the signal shows up in only a small number of events. Rival teams will try to reproduce the measurement with independent methods. Physicists say that kind of cross-check is what turns a hint into a confirmed observation.
More data on the way
Confirming a rare process takes time. The collider produces Higgs bosons at a limited rate, and only a tiny share follow this path. Researchers must separate faint signals from much larger backgrounds of ordinary events.
The team says upcoming runs will add more collisions and improve the precision of the measurement. For now, the finding adds a piece to a picture built over more than a decade of work at the machine.
Researchers say the measurement also tests how the Higgs couples to lighter particles, a sector that is harder to probe than its links to heavy particles. Future runs at higher intensity should allow a much sharper test, and the collaboration expects to report a firmer number within a few years.