If two protons were to collide with enough energy to form a black hole, the subsequent Hawking radiation would not directly contain positrons in place of protons. Let's explore this further.
Hawking radiation is a theoretical prediction made by physicist Stephen Hawking that suggests black holes can emit particles due to quantum effects near the event horizon. According to Hawking's theory, pairs of particles and antiparticles can be created near the black hole's event horizon. One particle falls into the black hole while the other escapes as Hawking radiation.
In the case of a black hole formed from the collision of two protons, the Hawking radiation would consist of a variety of particles, including photons, electrons, positrons, and other elementary particles. The specific particles produced in the Hawking radiation depend on various factors, such as the mass of the black hole, its charge, and the surrounding environment.
However, it's important to note that the formation of a black hole from the collision of two protons is highly unlikely under normal circumstances. The energy required to create a black hole is incredibly high, far beyond what can be achieved in current particle accelerators or natural processes. In reality, protons colliding at extremely high energies would more likely result in particle interactions and the production of other particles rather than the direct formation of a black hole.
So while the Hawking radiation from a black hole could contain positrons and other particles, the scenario you described—forming a black hole directly from colliding protons—is highly speculative and not currently achievable with our current understanding of physics.