It may therefore seem that DSR theories are ”empty”, in the sense that the new definitions of
and
are merely
mathematical manipulations without any physical meaning, i.e.
and
represent the true energy and momentum that
one would measure. For a discussion of this point see [203, 186
]. Since this is not a theoretical paper, we simply make
the DSR assumption that
and
are the measurable energy and momentum (or more specifically for
analysis of particle interactions, the energy and momentum that are assigned to in and out states in a scattering
problem).