The nature of particles

Question

since blackholes thermally create and emit sub-atomic particles, does spacetime govern the characteristics that particles display or does a particles characteristics form independently of spacetime?

Answer 1

We describe the elementary particles using quantum field theory. For every particle there is a corresponding quantum field, so for example electrons are described by the electron field. You can think of the particles as excitations of the quantum field, so if you add energy to the electron field that energy appears as an electron. Add more energy and you get another electron, and so on.

Hawking radiation exists because when we have a curved spacetime different observers will disagree about how much energy these quantum fields have, and therefore they will disagree about the number of particles that are present. There is an attempt to explain this in more detail in my answer to An explanation of Hawking Radiation.

So Hawking radiation cannot create new and unknown types of particle because we use the types of quantum fields, and therefore the types of article, as an input to the calculation. That is, first we specify what types of particle can be present and from this we can calculate how particles of those types are created by the Hawking radiation.