Charm baryon semileptonic decays

Victor Evgenjevich Pavlunin, Purdue University

Abstract

Using the CLEO detector at the Cornell Electron Storage Ring we have studied the angular distributions in the decay [special characters omitted]. By performing a four-dimensional maximum likelihood fit, the form factor ratio, R = f2/ f1, and the pole mass, determining the shape of the form factors, Mpole, are found to be −0.31 ± 0.05stat ± 0.04sys and (2.13 ± 0.07stat ± 0.10 sys) GeV/c2 respectively. These results correspond to the following value of the decay asymmetry parameter [special characters omitted] = −0.85 ± 0.03stat ± 0.02sys, for ⟨q2 ⟩ = 0.67 (GeV/c2)2. We search for CP violation in the angular distributions of the decay and find no evidence for CP violation: [special characters omitted] = 0.01 ± 0.03stat ± 0.01 sys ± [special characters omitted] where the third error is from the uncertainty in the world average of the CP violating parameter, [special characters omitted], for Λ0 → p+π −. We have also observed the [special characters omitted] (css ground state) in the decay [special characters omitted] → Ω−e+υ e. We find a signal of 11.4 ± 3.8 (stat) events. The probability that we have observed a background fluctuation is 7.6 × 10−5 . We measure B([special characters omitted] → Ω−e+υe ) · σ(e+e− → [special characters omitted]) = (42.2 ± 14.1(stat) ± 5.7(syst)) fb and R = [special characters omitted] = 0.41 ± 0.19(stat) ± 0.04(syst). This is the first statistically significant observation of an individual decay mode of the [special characters omitted] in e+e− annihilation, and the first example of a baryon decaying via β-emission, where no quarks from the first generation participate in the reaction.

Degree

Ph.D.

Advisors

Shipsey, Purdue University.

Subject Area

Particle physics

COinS