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The BaBar experiment results are very interesting indeed, but isn't that degree of asymmetry way too high to fit the observed state of the universe?
GreetingsThe universe is asymmetrical in that of it consists almost completely of normal mass, matter and energy. "This is lucky for us" as Symmetrical universe of equal amounts of matter and antimatter would have resulted in a universe of pure energy of Gama rays, no planets, stars, galaxies, just radiant energy.The big bang theory suggests that equal amounts of matter and antimatter should have been created at this event. But this did not happen Why??Alan
It's a little complicated: Anti-matter certainly exists, and for every type of particle there is a corresponding anti-particle. For many years it was thought that particles acted just like anti-particles, thus leading to the puzzle of whywe seem to see mostly matter. In the early 60's it was discovered -- at around the same time -- that both charge conjugation symmetry ( particles are equivalent toanti-particles ) and parity symmetry ( our world and mirror image world look the same)are not respected. However, for a few more years it was though that the combined symmetry(CP) was respected. I this were true then for every particle you would have an anti-particle of opposite parity, so still we would expect equal amounts of matterand anti-matter.In the late 60's Cronin and Fitch (who won the Nobel prize in 1980 for this) discoveredthat CP was not conserved when studying the decay/oscillation of a kaon to an anti-kaon.Such CP-violation is now part of the Standard Model of particle physics. Within the standard model this CP-violation is controlled by a single parameter. The aforementionedattempts to study CP-violation on the b-meson system are not an attempt to discoverCP-violation (been there, done that), but to get another extraction of this parameter. If it agrees with that from the kaon system (does so far), then the Standard Model looks good, it if differs (let's hope) then we have a handle to move beyond thestandard model. That being said: The Standard Model does lead to matter/anti-matter asymmetry,but, as observed, this effect comes entirely from the weak force and is *tiny*; certainly not enough to naively explain the asymmetry we see.However, this asymmetry could have been seeded in the early universe wherethe rules are very different than we see now. For example, there are several theories that use the fact that QCD (so the strong, not the weak force) canbreak CP to explain this; while we see no evidence that this happens inour experiments, this is an effect that should grow with energy. As such, itmight have been strong enough in the early universe to account for thematter/anti-matter asymmetry, while still being weak enough at the energies our current experiments probe that we couldn't measure it.
Quote from: LeeE on 14/11/2008 17:46:01Just another thought about anti-gravity...If anti-gravity acts as a repulsive force, will this have the opposite effect to time dilation? That is, the rate of time is highest for an infinitely distant observer where the gravitational field is infinitely small and this could be considered to be the base-line rate of time. The actual rate of time in the universe will always be lower than the base-line rate of time because the gravitational field everywhere in the observable universe is greater than infinitely small. However, if anti-gravity increases the rate of time, then as one approached an anti-matter black hole, time would pass more quickly and you'd start getting some very weird energy results.I knew there was something bugging me about that and it's just clicked.Gravitational time dilation is due to the curvature of spacetime. The greater the curvature, the greater the dilation. Gravity produces that curvature. So antigravity would produce anticurvature. And what is anti-curvature? It's flat. In flat spacetime there is no time dilation.HA... get out of that 1!
Just another thought about anti-gravity...If anti-gravity acts as a repulsive force, will this have the opposite effect to time dilation? That is, the rate of time is highest for an infinitely distant observer where the gravitational field is infinitely small and this could be considered to be the base-line rate of time. The actual rate of time in the universe will always be lower than the base-line rate of time because the gravitational field everywhere in the observable universe is greater than infinitely small. However, if anti-gravity increases the rate of time, then as one approached an anti-matter black hole, time would pass more quickly and you'd start getting some very weird energy results.
You know Guys,I started this thread and maybe (don't retract back in horror an disbelief) it is because God made it that wayAlan