reveals the possible existence of another closely related particle.”
And so, on and on it goes.
What’s the stuff that holds these particles together? Alas, we have since John Locke (or maybe Hobbes...) abandoned that question altogether.
But it seems like a good one.
>>What’s the stuff that holds these particles together?
If particles are merely a localized compression of Space relative to E within the observed system - then the answer is, they do.