A study of semileptonic and 2-body decays of charm strange baryons, a search for CP violation in Xi hyperon decays and a study of surface-treated planar microstrip gas chambers

Using the CLEO II detector at the Cornell Electron Storage Ring we search for evidence of W0c production at e+e - machines in the decay mode Oc → O e+nue. We find 10.4 +/- 3.8 candidate events. The probability that the background accounts for all events in the signal region as a statistical fluctuation is 7.7 x 10-4. Our result is B( W0c → O-e+nu e) · sigma(e+ e- → W0c X) = 0.22 +/- 0.08pb. We have measured the product of the decay asymmetry parameters, alphaLambdaalpha xi, in the decay chain xi- → Lambdapi -, Lambda → p+pi -. We find alphaLambdaalphaxi = -0.293 +/- 0.021+0.019-0.014 which is in good agreement with the current world average alpha Lambdaalphaxi = -0.293 +/- 0.007. Using our reconstructed sample of 4204 +/- 75 xi- and similar number of xi+, we search for evidence of direct CP violation by measuring the asymmetry, A , in the angular distribution of xi → Lambdapi charge conjugate states. In the Standard Model, direct CP violation in hyperons is expected to occur at the 10-4--10-5 level. The observation of CP violation at a higher level may indicate the presence of new physics. We find no evidence of CP violation: A ≃ Axi + A Lambda = -0.057 +/- 0.064 +/- 0.028. Given the world average ALambda = -0.03 +/- 0.06, we find Axi = -0.03 +/- 0.06 +/- 0.07. The systematic error is dominated by the ALambda measurement. We have measured the X0c decay asymmetry parameter in the decay X0c → xi-pi+. We find aX0c alphaxi = 0.26 +/- 0.18+0.05-0.04, , using the world average of alphaxi = -0.456 +/- 0.014 we obtain aX0c = -0.56 +/- 0.39+0.10-0.09 where aX0c is <0.1 at the 90% CL. The central value occupies the middle of the theoretically expected range but is not yet precise enough to choose between models.;We report on the study of surface treated planar microstrip gas chambers. We present the first observation of gas gain suppression in an ion-implanted kapton detector. We report on the results from a beam test on Kapton detectors carried out at the TRIUMF research facility in Vancouver, Canada. A study of the performance of microstrip gas chambers passivated by thin semiconducting glass and plastic films is presented.