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Title: Relativistic corrections to radiative transitions in quarkonium

Thesis/Dissertation ·
OSTI ID:6210258

In this work estimates are made of (v/c/sup 2/) corrections to E1 radiative decay rates in the psi and T systems. Siegert's theorem is used to reduce the problem of finding these corrections to one of finding (v/c)/sup 2/ corrections to quarkonium bound state wavefunctions. A Breit-Fermi equation is used to describe the c anti c and b anti b systems. Numerical calculations are carried out in two potential models. Each of these potentials consists of a linear confining piece and a Coulomb-like piece which incorporates a short distance cutoff. The short distance cutoff simplifies the calculation of bound state wavefunctions. In these models the best fit to the charmonium fine structure occurs when the confining potential is assumed to be a Lorentz scalar and the Coulomb-like potential is assumed to be a Lorentz vector. Quarkonium bound state wavefunctions which include spin dependent and spin independent (v/c)/sup 2/ corrections are found by solving the Breit-Fermi equation. These wavefunctions are used to calculate quarkonium E1 decay rates. It is found that the node in the 2S radial wavefunction makes the psi' ..-->.. ..gamma.. chi/sub J/ decays sensitive to relativistic effects, especially the fine structure. In particular, the psi' ..-->.. ..gamma.. chi/sub 0/ decay rate is reduced by more than a factor of two compared to the nonrelativistic estimate. The chi/sub J/ ..-->.. ..gamma.. psi decay widths are not sensitive to relativistic effects since neither the initial nor the final c anti c radial wavefunctions have nodes. Relativistic corrections to radiative E1 decay rates in the b anti b system are generally smaller than in the c anti c system. However, estimates of some decay rates, for example those for 2 /sup 3/P/sub J/ ..-->.. ..gamma..T, are very sensitive to wavefunction corrections. These estimates differ substantially from nonrelativistic predictions.

Research Organization:
California Univ., Los Angeles (USA)
OSTI ID:
6210258
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English