A new paper by the ATLAS collaboration at the CERN Large Hadron Collider produces results in good agreement with standard model predictions: the unitarity of the cross section of the vector-boson scattering process, one of the original reasons for invoking the Higgs mechanism, has been tested by directly searching for electroweak production of W boson pairs associated with two forward-going hadronic jets. The energy dependence of the rate of the considered process provides information on whether the unitarity-restoring action of the Higgs boson is total, as the standard model predicts, or only partial.
The above could be a reasonable abstract of an article describing this new nice result by ATLAS, which employed 8-TeV collision data collected in 2012 for the analysis. Unfortunately, that is also pretty much the body of this article, as I have little time today to go in the details of the study. I thought I would still publish here one of the key plots, which shows how the data allow the isolation of a reasonably clean sample of events from the searched process.



The bright-colored graph above shows the "rapidity difference" between the two jets that accompany the selected signature of an electron, a muon, and missing energy. As usual the black points describe the data, after a tight selection aimed at cleaning up the data from all contributing backgrounds as much as possible. Then, the "pale blue" component is the one we care about, labeled "EW WWjj production". There is a clear component of those events in the data passing the requirement that the rapidity difference of the two jets is larger than 2.4 (as one expects, vector boson scattering has the two jets flying apart in different directions).


The two leptons in the selected events, together with the neutrino-induced missing energy, originate from the leptonic decays of the two produced W particles, and the two jets are the result of forward-going quarks that radiated the W bosons before the latter ended up scattering off one another. 

In other words, these very peculiar events feature the protons as sources of W bosons: hadronic matter is, in a small part, constituted by weak bosons, in fact. One may sweep this under a "W boson PDF" of the proton, or decide to describe it as a hard-scattering phenomenon, but the physics is the same. (You can check here how the photon content of the proton, a similar issue, has been analyzed and quite successfully described recently, by Gavin Salam and collaborators).

The executive summary of the ATLAS paper is: all is good, the standard model continues to rule, and the Higgs does what we paid it for - it prevents scattering cross sections to diverge at high energy. This of course has also implications for many beyond-the-standard-model ideas. For more information, read the paper here.