2003/01/03 by Timo A. Lähde, T. A. Lahde, Lahde, T. A.
Physics and Astronomy · #Astrophysics and Star Formation Studies #Cosmology and Gravitation Theories #Stellar, planetary, and galactic studies #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/0301010
VII + 65 pages, uses feynmf. PhD dissertation. PDF version also available from http://ethesis.helsinki.fi/julkaisut/mat/fysik/vk/lahde/
arxiv created 2003/01/03 · arxiv updated 2009/11/30
The electromagnetic and pionic transitions in mesons with heavy flavor quarks are calculated within the framework of the covariant Blankenbecler-Sugar equation. The M1 transitions in the charmonium system are shown to be sensitive to the relativistic aspect of the spin-flip magnetic moment operator, and the Lorentz structure of the Q Q interaction. The observed rate for the M1 transition J/psi -> etac gamma is shown to provide strong evidence for a scalar confining interaction. The single pion and dipion widths are calculated for the heavy-light D mesons, by employment of the pseudovector pion-quark coupling suggested by chiral perturbation theory. The pionic transitions D* -> D pi are shown to provide constraining information on the pion-quark axial coupling gAq. It is also shown that axial exchange charge contributions associated with the Q q interaction suppress the axial charge amplitude for pion emission by an order of magnitude. The models for pi and M1 transitions also make it possible to estimate the eta-nucleon coupling from the transition Ds* -> Ds pi0, once the value of the pi0 - eta mixing angle is known. Finally, the dipion transition rates of the L=1 D mesons are calculated, and are shown to make up a significant fraction of their total widths for strong decay. The pipi transitions between S-wave charmonium and bottomonium states are modeled in terms of a broad sigma meson with derivative couplings to pions.