To be or not to be

Phys. Rev. Lett. 109, 111802 (2012)

Data from CERN would now seem to have answered the question posed last year by the laboratory's Director General, Rolf Heuer, about the Higgs boson: “To be, or not to be?” In July this year, the ATLAS and CMS collaborations reported signals touching the five-sigma significance level for a Higgs-like particle with a mass of 125 GeV c⁻². Meanwhile, the CDF collaboration have been completing their analyses of the final set of data delivered by Fermilab's Tevatron accelerator before it was shut down last year. Although their statement is not as definitive as that from CERN, the CDF collaboration have also found the hint of a signal in the same mass region.

The Tevatron's proton–antiproton collisions at a lower centre-of-mass energy than the proton–proton collisions at CERN offer a complementary system for the Higgs search, and one in which the decay of a Higgs boson to b quarks is more easily detected. Seeking the signature of a Higgs produced alongside a W or Z boson, with the Higgs then decaying to a b and anti-b quark pair, the CDF team found an excess in the data, peaking at a significance of 2.7 at a mass of 125 GeV c⁻².