We report on a new measurement of the branching ratio B(KL → π 0 γγ) using the KTeV detector. We reconstruct 1982 events with an estimated background of 608, that results in B(KL → π 0 γγ) = (1.29 ± 0.03stat ± 0.05syst) × 10 −6. We also measure the parameter, aV , which characterizes the strength of vector meson exchange terms in this decay. We find aV = −0.31 ± 0.05stat ± 0.07syst. These results utilize the full KTeV data set collected from 1997 to 2000 and supersede earlier KTeV measurements of the branching ratio and aV .

The recent discovery of a large CP violating asymmetry in KL-->pi+pi-e+e- mode has prompted us to seach for the associated KL-->pi 0 pi 0 e+e- decay mode in the KTeV-E799 experiment at Fermilab. In 2.7 x 10(11) K(L) decays, one candidate event has been observed with an expected background of 0.3 event, resulting in an upper limit for the KL-->pi 0 pi 0 e+e- branching ratio of 6.6 x 10(-9) at the 90% C.L.

Polarization results from the Cosmic Anisotropy Polarization MAPper (CAPMAP) experiment are reported. These are based on 433 hr, after cuts, observing a 2 deg 2 patch around the north celestial pole with four 90 GHz correlation polarimeters coupled to optics defining 4Ј beams. The E-mode flat band-power anisotropy within is measured as mK 2 ; the 95% confidence level upper limit for B-mode power withinis measured as 38 mK 2 .ϩ590 1050 Ϫ520

The formalism necessary to understand the phenomenon of CP noneonservation as observed in the neutral-kaon system is presented. The distinction between indirect CP violation and direct CP violation is made, and the level of understanding of the phenomenon in the standard model is reviewed. Attention is placed on new experimental efforts that could definitely establish a first-order or direct effect. The authors analyze the potential for such an observation in both kaon and J3-meson decays and give the range of predictions from the standard model. Other possible models are considered briefly.