Sufficient numbers of people were willing to believe in at least the possibility of a Higg's Boson, to go to considerable trouble and expense to find it.
And, given the detail and depth of the theory that proposed it, that is a reasonable tactic: don't claim belief until there is evidence, but explore to see what the evidence gives.
So, once again, evidence comes *before* belief.
Meanwhile, the Large Hadron Collider is still searching for the missing magnetic monopole, I believe. And the idealists among us are still searching for the meaning of life.
And it would be very interesting *if* monopoles are discovered. But NOBODY is saying monopoles definitely exist. They are saying that some theories predict them, others do not, and the search is worth the distinction between the two. We don't know, so we explore.
If the notion of a God had even close to as much evidentiary and logical support as do monopoles, nobody would disagree with doing an experiment to see if such a thing exists. But they *would* disagree with claiming existence *before* there was enough evidence in to justify that claim.
I would also point out that the LHC does MUCH, MUCH more than simply looking for monopoles. it would be nice if they are found (or shown to be impossible), but that is hardly the only (or even primary) goal of the LHC.
But, once again, you don't start with belief and then look to find evidence. That is encouraging confirmation bias. Instead, you start with a possibility and then look for evidence *both ways* and see where the pieces end up.
Many people have done the test of Jesus given in your holy book (I knock at the door...) and found that the test failed to provide evidence. That is enough for them to continue on with other, better, hypotheses.