Regular matter particles have an intrinsic spin defined by the right-hand rule. Form a fist with your right hand, thumb pointing upward. That’s spin up. Rotate your wrist 180 degrees so your thumb points downward. That’s spin down.
Antimatter particles have properties exactly opposite to normal patter particles. They’re 180 degrees out of phase. They’re mirror reversed. Positive charge becomes negative charge. Spin becomes anti-spin, therefore right handed spin becomes left handed spin.
The implication is profound. Anti-particles have anti-spin, which must be anti-time. When we examine anti-particles, we see them have spin up and spin down, just like normal matter. This is a fundamental limitation of our testing methods. A right handed up spin looks like a left handed down spin. A right handed down spin looks like a left handed up spin. If you make fists with both hands, thumbs pointing up, you see them curling in opposite directions. Your mirror self looks exactly like you, but with everything reversed. Your right hand is your mirror twin’s left hand.
That implies that the subjective measure of time is expressed by the intrinsic spin of a particle. Matter has positive time. Antimatter has negative time. This is the only way to make the mirror universes match and be internally consistent.
An electron has spin up or down and positive time, which combine to +up or +down
A positron has spin up or down and negative time, which combine to -up or -down.
This is why the Dirac equation derives negative energy particles. This comes from the four component spinor: +up, +down, -up, -down. Feynman correctly interpreted these “negative energy” particles as positive energy anti-particles moving backwards in time.
But the time they’re moving backwards through isn’t the objective, universal tick. (In our positive time, normal matter universe, objective time only flows forwards.) It’s the subjective tick of each particle, wholly constrained by the strictures of relativity. An anti-particle’s negative sign shows it as acting in opposition to the universal tick. Similar terms multiply to a positive. Dissimilar terms multiply to a minus. Both universes are exactly equivalent, although opposite. (In the anti-universe, time flows backwards, and what we consider antiparticles are the norm and act in concert with the reversed time flow.)
In each universe, down-oriented neutrinos interact through the weak force with normal particles. Up oriented neutrinos interact with antiparticles. There is no way to tell which universe you’re in.
Spin is quantized. I have previously shown that spin 1 particles (bosons) are time neutral, while spin 1/2 particles (fermions) carry either positive or negative time. It’s the simplest way to make the equations balance, and it even makes sense.
Copenhagen interpretation delenda est!