I'm really not too happy about this because the Nobel prize has shunned deserving scientists again. The consensus is that this mechanism can be attributed to three papers, One from Englert and Brout, another from Higgs, and yet another from Guralnik, Hagen and Kibble.
The silly rule of having to give the award to at most three living authors rules out Brout and, as it would be a problem to choose one of GHK (because they signed in alphabetical order, good for them) it's too obvious why they're out, even when the current understanding of the theory can be traced back to their string of papers.
This is not the first time: for instance, nobody really understands why Cabibbo wasn't awarded some years ago along with Kobayashi and Maskawa... for the CKM matrix!