In December 2015, scientists at the Large Hadron Collider (LHC) thought they may have seen a hint of a brand-new particle. This appeared by way of a couple of 'bumps' in the data, which triggered such an avalanche of interest that 500 papers followed. But, alas, subsequent research has shown that there really was no such particle:

'"The bad news is [the measurements] don't show anything," said theoretical physicist Matt Strassler. "The good news is that it did a really good job of not showing anything."

From here.

There's a good analysis on The Atlantic Monthly called Back to the Drawing Board which goes into some of the philosophical implications of this non-discovery. In brief, the story is as follows: whilst the discovery of the God Particle, er, Higgs Boson, was a triumph, it might also signal, according to some, the end of the road for particle physics. It confirms many major aspects of the 'standard model', but the problem with that model is its 'unnaturalness'. There are many things about it which are 'just so', but for which there doesn't appear to be any explanation:

Aside from having a large number of different particles and forces, many of which seem surplus to requirement, [the Standard Model] is also very precariously balanced. If you change any of the 20+ numbers that have to be put into the theory even a little, you rapidly find yourself living in a universe without atoms. This spooky fine-tuning worries many physicists, leaving the universe looking as though it has been set up in just the right way for life to exist. — Harry Cliff

from here.

It was hoped that 'supersymmetry' might provide a deeper level of explanation, a 'why is it so', that would account for the spooky just-so-ness of the Higgs, among other things - but nothing has turned up; the excitement about the bump-that-dissappeared was that this might have been one such discovery. But no - and many are saying that it might be over for supersymmetry (hence the title of the Atlantic article).

The Atlantic likewise comments:

Many particle theorists now acknowledge a long-looming possibility: that the mass of the Higgs boson is simply unnatural—its small value resulting from an accidental, fine-tuned cancellation in a cosmic game of tug-of-war—and that we observe such a peculiar property because our lives depend on it. In this scenario, there are many, many universes, each shaped by different chance combinations of effects. Out of all these universes, only the ones with accidentally lightweight Higgs bosons will allow atoms to form and thus give rise to living beings. But this “anthropic” argument is widely disliked for being seemingly untestable.

'Untestability' is not the only reason it's disliked, I suspect. But I do wonder if we're in some sense at the end of explanation at this point in history - that we will have to live with the 'just-so-ness' for the indefinite future. Of course, I don't know that, but as someone now in his sixth decade, I am also pretty dubious that this is something that will be cleared up in my lifetime.