  We carry out a systematic study of the bounds that can be set on Planck-scale
deformations of relativistic symmetries and CPT from precision measurements of
particle and antiparticle lifetimes. Elaborating on our earlier work [1] we
discuss a new form of departure from CPT invariance linked to the possibility
of a non-trivial geometry of four-momentum and its consequences for the
particle and antiparticle mass-shells and decay probabilities. Our main result
is a collection of experimental bounds that can be obtained for the deformation
parameter of the theoretical model under consideration based on current data
and sensitivities of planned experiments at high energies.
