Rare Kaon Decays and CP Violation
Abstract
Description
Rare kaon decays are an important testing ground of the electroweak flavor theory: They can provide new signals of CP-violating phenomena. The interplay of long-distance QCD effects in strangeness-changing transitions can be analyzed with Chiral Perturbation Theory techniques. In particular, two rare kaon decays are analyzed: The first decay, K_L -> pi0 e+e-, is being searched for as a signal of direct Delta S = 1 CP violation. We provide a thorough updating of the analysis of the three components of the decay: 1) Direct CP violation, 2) CP violation through the mass matrix and 3) CP-conserving (two-photon) contributions. First the chiral calculation of the K_S -> pi0 e+e- rate is updated to include recent results on the nonleptonic amplitude. Then we systematically explore the uncertainties in this method. The CP-conserving amplitude remains somewhat uncertain, but present indications are such that there may be a sizable CP-violating asymmetry in the e+, e- energies from the interference of CP-conserving and CP-violating amplitudes. This may potentially be useful in determining whether direct CP violation is present. The second decay, K_L -> pi0 gamma e+e-, which occurs at a higher rate than the nonradiative process K_L -> pi0 e+e-, can be a background to CP violation studies using the latter reaction. The leading order chiral loop contribution to K_L -> pi0 gamma e+e- is completely calculable.
Ph.D. Thesis, September 1997. 104 pages, 31 eps figures. LaTeX, uses epsf.sty, umthesis.sty (included). Two references added, misprints corrected
Ph.D. Thesis, September 1997. 104 pages, 31 eps figures. LaTeX, uses epsf.sty, umthesis.sty (included). Two references added, misprints corrected