AuthorHamm, Jason C.
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PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractThe rare decay K(L) → e⁺e⁻μ⁺μ⁻ offers the best opportunity to study the dynamics behind the KL γ*γ* vertex. This information is needed to subtract the long-distance contribution to the decay K(L) → μ⁺μ⁻, allowing for a calculation of rho, the real part of the CKM matrix element Vtd. Analysis of data from the 1997 and 1999 runs of the KTeV experiment has isolated a sample of 132 K(L) → e⁺e⁻μ⁺μ⁻ events, with an estimated background of 0.8 events. Based on this data, the branching ratio for this mode was calculated to be B(K(L) → e⁺e⁻μ⁺μ⁻) = (2.63 ± 0.23(stat) ± 0.13(syst)) x 10⁻⁹, where a radiative cutoff has been imposed at x(e⁺e⁻μ⁺μ⁻) > 0.95. The D'Ambrosio, Isidori, and Portoles K(L) γ*γ* linear form factor parameter alpha was measured to be -1.52 ± 0.38, consistent with previous experimental results. Little sensitivity was found to the quadratic parameter beta, resulting in a measured value of +12.3 ± 77.1. The asymmetry in the angular distribution of the K(L) → e⁺e⁻μ⁺μ⁻ decay products was measured to be A < 25.5% with 90% confidence, constraining the size of any CP-violating contribution to the K(L) gamma*gamma* interaction. Finally, a 90% C.L. upper limit of 4.12 x 10⁻¹¹ was placed on the branching ratio of the lepton flavor-violating mode K(L) → e⁺/⁻ e⁺/⁻μ⁺/⁻μ⁺/⁻, a full factor of 3 improvement over the current limit.
Degree ProgramGraduate College