I'm going to have to revise a few diagrams I made earlier to illustrate this (I was misguided/wrong about a couple things in them), but the recent observation that anti-atoms emit light, too, was... encouraging.
I still see sense in my prediction that mass is mismatched particle pairs (which I will get to in a second), but I was most likely wrong about it being gravity that makes them bond to each other, as it would make more sense that it is their polarity that makes them try to annihilate each other... but mismatched quarks would have to (practically) touch for this to happen. Maybe.
To sum up my idea this far: a photon and a particle pair are essentially the same thing at different energy levels. Not 'electromagnetic' at all, I hypothesise that a 'light wave' (photon) is, in fact, a 'balance' of energy and a force that we would call gravity. Like a bucket swung on a string, the more energy one puts into the rotation (the faster the rotation), the higher the sensation of gravity; the two, in essence, are a tug-of-war balance against each other, and this is the source of the 'constant' that is 'light-speed' C.
It works this way for a forward c-travelling energy wave, with the 'gravity' being the force that causes the energy to oscillate across polarities; yet above a certain energy level, the oscillation will 'overcome' polarity axis and forward motion, and the wave will 'split' into its positive and negative polarities... we would call these 'quarks' (but henceforth 'particles', here). And, as they are perfectly matched (they are, essentially, halves of the same thing), they should annihilate each other perfectly.
But if, after particle creation, the particles are estranged from each other, they may meet another not-same-energy-level one, and, should they touch/near (again, the 'how' of this is still not clear to me), they will annihilate each other, 'creating' either a photon or smaller particle equalling the energy difference between the two.
But should three particles, one of one charge and the other two of opposing charge, meet each other instantaneously, they would try desperately to annihilate each other, but the two same-charge particles would prevent that from happening (while being 'bonded' across the opposite-charge particle): this is called a 'hadron'.
But, in particle physics, there are two forms of hadron: 'neutral charge' neutrons and positively-charged protons. I still have a lot of questions about how this comes to be (are neutrons really so 'neutral', or perhaps is this distribution an 'outcome' of further particle interaction), but going there would digress from what I'm trying to address here.
But the 'bonding' I describe above only involves one half of a particle (pair): what happens to the other 'estranged' half?
This model, if it is demonstrable, would explain both radioactive decay (nuclear half-life) and Einstein's "spooky action at a distance", as, since both particles of a pair are one half of a same thing, something affecting one of them would also affect the other. For example, were an electron annihilated by a positron, their 'opposing twins' would be affected, too, and one or both of them are 'bonded' in some way to other particles in a stable manner, their disparition would make the bonding unstable, causing it to be affected by surrounding particles, or, in other words, decay. And it would make sense that the 'distance' separating twin particle-pairs doesn't matter; any change to one would instantly affect the other.
Were this true, the implications and possibilities (instantanious communication, etc.) would be myriad: this is becoming almost exciting.