Two-photon helicity selection rules and widths for positronium and quarkonium states with arbitrary angular momenta
Abstract
The observation of a large γγ width for the 1D2 qq¯ state π2(1670) suggests that the γγ couplings of many orbitally excited light-quark qq¯ states may be experimentally accessible. In this paper we present γγ helicity amplitudes for nonrelativistic fermion-antifermion states with general angular-momentum quantum numbers 1lj and 3lj, and note some relations and selection rules that may be useful in the spectroscopic classification of orbital excitations.
- Publication:
-
Physical Review D
- Pub Date:
- September 1992
- DOI:
- 10.1103/PhysRevD.46.2257
- Bibcode:
- 1992PhRvD..46.2257A
- Keywords:
-
- 13.40.Hq;
- 12.40.Qq;
- 14.40.Cs;
- 36.10.Dr;
- Electromagnetic decays;
- Other mesons with S=C=0 mass<
- 2.5 GeV;
- Positronium muonium muonic atoms and molecules