Dissertation/Thesis Abstract

A study of interference effects in photoproduced rho, omega and phi vector mesons decaying into the muon+ muon- final state and a measurement of the psi meson decaying to muon+ muon- branching fraction
by Frisullo, Valeria, Ph.D., University of Colorado at Boulder, 2010, 162; 3404047
Abstract (Summary)

This thesis is a study of the photoproduction of light and charmed-anticharmed mesons, using data collected by the FOCUS experiment. FOCUS is a fixed target photoproduction experiment at Fermi National Accelerator Laboratory (Fermi-lab), that collected data during 1996-1997. The experiment had a dimuon trigger which allowed us to obtain a very large sample of dimuon events.

The first analysis focuses on the study of the low mass vector mesons ρ, ω and &phis;, and provides the first high statistics measurement of the ρ – &phis; and ρ – ω interference phases using muons. Attempts to determine such parameters, necessary for a better understanding of the production mechanisms of these vector mesons, date back to the end of the '60's, but a consistent analysis using leptonic final states ( e+e or μ +μ) is still missing. Our results are: [special characters omitted]

Our second analysis studies the ψ' charmonium state and determines its branching fraction (BF) into the μ+μ decay channel. The technique used to extract the BFψ'→μ +μ consists of measuring the yield of the ψ' → μ+μ decay (Y2b) relative to the yield of ψ' → J/ψπ+π, where the J/ψ decays in μ +μ (Y4 b). Fitting the ψ' peak in the μ+μ and μ+μ π +π mass plots, we report signal event yields of Y2b = 563 ± 35 and Y4b = 1262 ± 39. These measurements allow us to evaluate the ψ' branching fraction as: [special characters omitted] This result significantly improves the precision of the world average value.

Indexing (document details)
Advisor: Cumalat, John P.
Commitee: Marino, Alysia D., Snow, Theodore P., Stenson, Kevin M., de Alwis, Senarath P.
School: University of Colorado at Boulder
Department: Physics
School Location: United States -- Colorado
Source: DAI-B 71/06, Dissertation Abstracts International
Subjects: Particle physics
Keywords: Branching fraction, Interference effects, Muons, Psi mesons, Vector mesons
Publication Number: 3404047
ISBN: 9781109782257