The difficulty in producing a black hole is getting the energy density high enough. We have no known mechanism to get an energy density that's even close the right order of magnitude.
Maybe you meant that in theory quantum fluctuations might do it? Unfortunately, this is really a non-answer. The probability is so ridiculously low that it's not practicably distinguishable from zero. (It's _vastly_ more likely that every measurement ever taken and that _will_ be ever taken is wrong, than that the event actually happened).
I have to use "theory" loosely here, because there isn't any known or suspected way to do it. The energy, as you observer, is off by orders of magnitude.
It's just that it's "merely" orders of magnitude. The odds were ludicrously low, but with a whole lot of particles being collided. So maybe, ridiculous outside chance, they might see one event out of the 10^20 events to be observed.
But almost certainly not. So it was never worth talking about. But people loved to talk about black holes, so the math got done.
The difficulty in producing a black hole is getting the energy density high enough. We have no known mechanism to get an energy density that's even close the right order of magnitude.
Maybe you meant that in theory quantum fluctuations might do it? Unfortunately, this is really a non-answer. The probability is so ridiculously low that it's not practicably distinguishable from zero. (It's _vastly_ more likely that every measurement ever taken and that _will_ be ever taken is wrong, than that the event actually happened).