Why does CP-Violation occur?

Question

I'm taking Astronomy right now, but my teacher's doing an awful job at teaching it. I'm doing a project on Antimatter, but I'm having trouble understanding some of these concepts. From my research, I know what CP-transformation/operation is, and that CP-Violation explains the Matter/Antimatter Asymmetry, but why does it happen? (And how?)

Answer 1

wow. deep question. I'm amazed!
lets research that one.......I'm looking at info on wiki
http://en.wikipedia.org/wiki/CP_violation
and an article for CERN
http://cerncourier.com/cws/article/cern/28025

I'm unable to answer your question, WHY, it seems to be an extension of parity
http://en.wikipedia.org/wiki/Parity_%28physics%29#parity_violation

but hopefully I've given you some helpful links.

Answer 2

I think the 'why' question is very difficult to answer. It seems to be related to underlying mechanisms. It is likely that it relates to symmetry breaking energies in the early seconds of the big bang. Why there is more matter than antimatter is still uncertain within the Standard Model.

I think the 'how' relates very much to the Weak Interaction/Force. The only way to understand this is to go back to the initial principles of the forces. Have a look at a few feynman diagrams of those interactions.

Cosmology in the current era is starting to be very diverse. Many ideas are 'up for grabs'. For example there is some possiblity good evidence for 'brane' cosmology which may have important implications for a range of things including dark matter and imbalance of matter and anti matter.

the idea that the universe was created from the ' touching' of branes from 'the bulk' could be very important in matter antimatter imbalance and also dark matter/energ.

Answer 3

I too am deeply vexed by those 0.3% or so of K meson decays that are not invariant under the product of charge conjugation and parity inversion, and like other scientists deem it to be one of the persistent mysteries of physics. Briefly, there are two neutral kaon states which have strangeness S = +1 and S = -1. Since strangeness is not conserved in weak interactions, these states can be interconverted by higher-order weak processes. This is in marked contrast to other particle-antiparticle systems, for which such transitions are forbidden, because the particle and its antiparticle differ by quantum numbers that are conserved in all known interactions. For neutral kaons however, such as K-short and K-long (in reference to their disparate lifetimes), there is no conserved quantum number to distinguish them when weak interactions are taken into account and the observed physical particles correspond not to the neutral kaon and its antiparticle but rather to a linear combination of them (in analogy to the CKM mixing scheme for quarks). This leads to kaon mixing and strangeness oscillations.
Experimentally, K-short and K-long have almost equal masses of about 499 MeV / c^2, but very different lifetimes and decay modes. K-short has a lifetime of 0.89X10^-10 s
and decays overwhelmingly to two pions, whereas K-long has a lifetime of 0.52X10^-7 s with a significant branching ratio to three pions, but not two. However, in 1964 all of this changed when it was observed that K-long also decayed to two pions with very small branching ratio of the order of 10^-3, clear evidence of CP violation! I am sure that you know all of this elementary background information, but I must close by observing the rather puzzling result (that I alluded to obliquely ab initio) that although the CKM mixing model adequately accounts for all CP-violating data to date, it fails (by several orders of magnitude) to account for the observed matter-antimatter asymmetry observed in the universe. Is it possible that a CP-violating mechanism beyond the standard model lies just beyond our ken...? I am sorry that I could not be of greater assistance, but problems of space and time of a far more pedestrian nature also exist which regrettably I cannot now violate -- HAH!