The widths for pi pi decay of the L = 1 charm mesons are calculated by desc
ribing the pion coupling to light constituents quarks by the lowest-order c
hiral interaction. The wavefunctions of the charm mesons are obtained as so
lutions to the covariant Blankenbecler-Sugar equation. These solutions corr
espond to an interaction Hamiltonian modeled as the sum of a linear scalar
confining and a screened one-gluon exchange (OGE) interaction. This interac
tion induces a two-quark contribution to the amplitude for two-pion decay,
which is found to interfere destructively with the single-quark amplitude.
For the currently known L = 1 D mesons, the total pi pi -decay widths are f
ound to be similar to1 MeV for the D-1 (2420) and similar to3 MeV for the D
-2* (2460) if the axial coupling of the constituent quark is taken to be g(
A)(q) = 1. The as yet undiscovered spin-singlet D-1* state is predicted to
have a larger width of 7-10 MeV for pi pi decay. (C) 2001 Elsevier Science
B.V. All rights reserved.