Yet as the $ 6.5 - billion LHC has forged ahead,
the neutron EDM experiments, with modest budgets of tens of millions of dollars, have hit a wall.
Despite the problems, nuclear and particle physicists continue to express broad support for
the neutron EDM studies, which they say are a unique complement to the LHC work.
But a larger
neutron EDM, possibly detectable by the latest efforts, could point to physics beyond the standard model (see «Lowering the bar»).
Not exact matches
It aims to detect the
neutron's presumed
EDM by looking for changes in the light emitted when cold
neutrons interact with helium - 3 nuclei in the presence of an electric field, a process that is subtly altered if the
neutron has an
EDM.
An
EDM for the
neutron would violate charge - parity symmetry, which dictates that particle interactions are unchanged when particles are replaced by their antimatter counterparts and by their mirror images.