Search for CP violation at CLEO

CP violation (CPV ) was first observed nearly 40 years ago in the form of mixing-induced CPV in neutral kaon decays [1]. With the the recent confirmation of the observation of direct CP violation in neutral kaon decays [2], only CPV due to the interference between mixing and decay remains to be observed. With the advent of the asymmetric B-factories, this phenomenon may soon be observed with a measurement of sin 2β [3–5]. The latter measurement has the advantage of a nearly unambiguous interpretation in terms of the description of weak decays in the standard model (SM). CLEO has performed a number of searches for CPV in beauty and charm meson decays. By and large the asymmetries expected in the SM are significantly smaller than the experimental precision so the results are primarily searches for physics beyond the SM. The CLEO results for B mesons are based upon 9.7 × 10 BB pairs collected at the Υ(4S) resonance with the CLEOII (3.3 × 10 BB ) and CLEOII.V (6.4 × 10 BB ) detector configurations at the CESR symmetric ee colllider. The search for mixing and CPV in neutral charm meson decays utilizes 9.0 fb of ee collisions at √ s ≈ 10.6 GeV accumulated with the CLEOII.V configuration. The inner wire chamber and 3.5 cm radius beampipe of CLEOII[6] were replaced by a 2.0 cm radius beampipe and a three-layer, double-sided silicon vertex detector (SVX) to create CLEOII.V[7]. In addition the argon:ethane gas mixture in the main drift chamber was replaced by a helium:propane mixture. The resulting improvements in momentum and specific ionization (dE/dx) resolution permitted better separation