  Many works, aiming to explain the origin of dark matter or dark energy,
consider the existence of hidden (brane)worlds parallel to our own visible
world - our usual universe - in a multidimensional bulk. Hidden braneworlds
allow for hidden copies of the Standard Model. For instance, atoms hidden in a
hidden brane could exist as dark matter candidates. As a way to constrain such
hypotheses, the possibility for neutron-hidden neutron swapping can be tested
thanks to disappearance-reappearance experiments also known as
passing-through-walls neutron experiments. The neutron-hidden neutron coupling
$g$ can be constrained from those experiments. While $g$ could be arbitrarily
small, previous works involving a $M_4 \times R_1$ bulk, with DGP branes, show
that $g$ then possesses a value which is reachable experimentally. It is of
crucial interest to know if a reachable value for $g$ is universal or not and
to estimate its magnitude. Indeed, it would allow, in a near future, to reject
definitively - or not - the existence of hidden braneworlds from experiments.
In the present paper, we explore this issue by calculating $g$ for DGP branes,
for $M_4 \times S_1/Z_2$, $M_4 \times R_2$ and $M_4 \times T^2$ bulks. As a
major result, no disappearance-reappearance experiment would definitively
universally rules out the existence of hidden worlds endowed with their own
copy of Standard Model particles, excepted for specific scenarios with
conditions reachable in future experiments.
