Recently it has been suggested that top quarks, or very massive fourth
generation quarks, might surround themselves with a Higgs ''bag'' of
deformation of the Higgs expectation value from its vacuum magnitude.
In this paper we address the question of whether such non-linear Higgs
-top interaction effects are subject to experimental test. We first no
te that if top quarks were necessarily accompanied by Higgs ''bags'',
then top quark weak decay would involve the sudden disruption of the H
iggs ''bag'', with copious production of physical Higgs particles acco
mpanying the decay. We then examine the effects that such Higgs ''bags
'' would produce on the spectrum of toponium, where the two bound top
(anti)quarks, and their ''bags'', overlap. We numerically evaluate the
effects that the non-linear feedback in the Higgs-toponium system wou
ld have on the energy level splittings of the toponium bound states, a
nd find that for allowed values of the top and Higgs mass the effect i
s negligible, thus indicating that even in this favourable circumstanc
e Higgs ''bag'' formation around top quarks does not observably occur.
Finally, we consider the case of a second Higgs doublet, allowing the
possibility of enhanced couplings for one of the physical Higgs to to
p. Even in this non-standard scenario the effects are minimal, and we
infer the general absence of observable effects at any level that migh
t suggest the utility of considering top quarks to be accompanied by H
iggs ''bags''.