Sigma
Abstract
This dissertation presents results of a study of Sigma_ c production in the Upsilon energy region. The experiment was performed at the Cornell Electron Storage Ring using the CLEO detector, the CLEO detector is a large-aperture magnetic detector. Previous experiments have presented inconsistent values for the mass difference M(Sigma_sp {c}{0}) - M( Lambda_sp{c}{+} ) differing by 10.8 MeV/c^2, while agreeing on the value for M(Sigma_sp {c}{++}) - M( Lambda_sp{c}{+} ). This analysis measures both of these mass differences. We find M(Sigma_sp{c}{++ }) - M(Lambda _sp{c}{+}) = 167.8 +/- 0.5 +/- 0.3 MeV/c ^2, which is consistent with the previous measurements; and M(Sigma_sp {c}{0}) - M( Lambda_sp{c}{+} ) = 167.9 +/- 0.5 +/- 0.3 MeV/c^2, which is consistent with one of the previous measurements. The ratio of production cross section for Sigma _{c} relative to Lambda _sp{c}{+} is measured to be 0.18 +/- 0.04 +/- 0.06. The mass difference measurements provide test models of baryon spectroscopy and the ratio of Sigma_{c} to Lambda _sp{c}{+} production cross sections provides information on the ratio of spin 1 to spin 0 diquarks providing a test of models of baryon hadronization. Finally, we have searched for Sigma _{c} production in B meson decay, where we have used data taken on the Upsilon(4S) for our sample of B mesons. We have found some evidence for the Sigma_sp{c} {++} in B decay, but the result of Sigma_sp{c}{0} analysis is inconclusive. The relative branching ratio of Br(B toSigma_sp {c}{++}X):Br(B toLambda_sp{c}{+ }Y) is measured to be 0.16 +/- 0.08 +/- 0.05 and Br (B toSigma_sp{c }{0}X):Br(B toLambda_sp{c}{+} Y) < 0.16 @ the 90% confidence level.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1989
- Bibcode:
- 1989PhDT.......181L
- Keywords:
-
- C) PRODUCTION FROM ELECTRON-POSITRON ANNIHILATION IN THE UPSILON ENERGY REGION (SIGMA(C);
- ELECTRON-POSITRON;
- UPSILON ENERGY REGION;
- Physics: Elementary Particles and High Energy