Study of the strong interaction effects associated with heavy quark systems in the Upsilon(4S) energy region

Wei-Ming Yao, Purdue University

Abstract

The specific strong interaction effects associated with heavy quark systems in the $\Upsilon$(4S) energy region have been studied using data collected with the CLEO detector at the Cornell Electron Storage Ring (CESR). We report on the observation of $\psi$ mesons from $\Upsilon$(4S) decays which are too energetic to come from B mesons. These events provide the first evidence for non-BB decay of the $\Upsilon$(4S). The measured rate is $Br(\Upsilon(4S)\to\psi X)$ = (0.22 $\pm$ 0.06 $\pm$ 0.04)% for $\psi$ momenta above 2 GeV/c. We also report on the first positive evidence of a signal for $D\sbsp{s}{+}\to\phi l\sp+\nu$. We have measured the ratio $\Gamma(D\sbsp{s}{+}\to\phi l\sp+\nu)/\Gamma(D\sbsp{s}{+}\to\phi\pi\sp+$) = 0.49 $\pm$ 0.10$\sbsp{-0.14}{+0.10}$ and use this measurement to determine the absolute branching ratio of $D\sbsp{s}{+}\to\phi\pi\sp+$ as $Br(D\sbsp{s}{+}\to\phi\pi\sp+$) = (3.1 $\pm$ 0.6$\sbsp{-0.6}{+0.9}\pm$ 0.6)%.

Degree

Ph.D.

Advisors

Shibata, Purdue University.

Subject Area

Particle physics

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