I wanted to put a clarification and provide some context about my question of today’s vidchat. Especially the part about the hunt for negative gravitational mass particles.
In his seminal paper where he introduced the equation baring his name, Paul Dirac’s original idea for antimatter was to have states with negative energy and mass as they were valid solutions of the Dirac equation.
https://royalsocietypublishing.org/doi/10.1098/rspa.1928.0023
His view would later be contested because the expression for the probability current is proportional to mass and energy (to E/m more precisely) this would lead to negative probabilities for certain quantum states, which of course is a mathematical aberration.
Feynman and Stuckelberg found a different interpretation to Dirac’s negative sea of electron as a simple charge and momentum inversion symmetry which lead to the discovery of the positron we know today. Most observed antimatter emerges from charge C and mirror momentum parity P.
However, while accepting the reality of the positron Dirac continued to insist that a mass symmetry M to -M does exist and the true anti-electron is the combination of charge, momentum, and mass inversion. something which will lead to positive probability currents as (-E / -m = E/m).
He believed that while the positron does exist the true anti-electron has still not yet been found experimentally. This is what I was referring to in my question when I talked about negative gravity mass. Indeed such anti-electron would be repelled by any matter present in our solar system and thus must be very rare and difficult to create and observe.
Its possible to get this kind of mass inversion in extreme conditions like inside a black hole. Or inside a particle accelerator with very high energies approaching those black hole conditions.
Thanks to all for your patience
Best