Ten years ago, on July 4th, 2012, the ATLAS and CMS Collaborations at CERN’s Large Hadron Collider (LHC) announced the discovery of a new particle with a mass of 125 GeV. Rather shortly after there were no doubts left that this new particle was the long sought-for Higgs boson (H), the unique elementary scalar particle, heralding the validity of the Brout-Englert-Higgs mechanism of spontaneous breaking the symmetry for the electroweak sector of the Standard Model (SM), predicted in 1964.
This was a major discovery in particle physics. The experimental measurements and theoretical understanding of the Higgs boson have progressed remarkably over the past decade. This happened thanks to an exemplary interplay between advanced theoretical investigations and sophisticated experimental methods exploiting the data delivered by a highly performant LHC. The rich harvest in data, already accumulated and further anticipated with the coming LHC run and the upgrades of both experiments and collider for the High-Luminosity LHC years, allows one to explore the Higgs boson as a portal to physics Beyond the SM (BSM).
The ambition of this special issue of LHEP is not only to document our current knowledge of Higgs physics in an up-to-date and concise way, but also to discuss its role in future searches for BSM physics, and its implications for new directions in cosmology.
The two figures, from the ATLAS and CMS experiments at CERN, illustrate the scope. The first one shows the latest measurements of the reduced H coupling strength modifiers to SM particles, and the second one is an example of an event consistent with the signature of a hypothetical vector-like quark T’ decaying into a top quark and an H boson. (Both figures: credit CERN)