[ephimetheus]

Neutrons are just as complex, they’re much harder to study though.

[gozzoo]

If i remember correctly Feynman said in one of his lectures that we know the mass of the electron with much greater precision than the proton, which may mean that it electrons are easier to study. I don't know if this is still true though.

[ephimetheus]

Oh yes and so much so! Electrons are point-like (not composite like a proton) and interact only electroweakly (not strongly).

[anamexis]

And neutrons are neither.

[TheOtherHobbes]

If it was possible to build a direct neutron accelerator/collider, I suspect we'd get some new physics pretty quickly.

Analysing hand-me-down neutron events from indirect collisions isn't quite as useful.

[librasteve]

At ISIS (Oxford neutron source)…

Spallation generation: High-energy protons (~800 MeV) hit a heavy target, releasing a wide spectrum of fast neutrons up to hundreds of MeV. These are then moderated down to useful energies for experiments.

It’s not the LHC, sure. But I don’t see any reason (apart from “why bother”) why they can’t do spallation in Geneva. OK maybe there’s a cooling problem…

[ephimetheus]

There absolutely are direct neutron experiments, but they are much lower energy and have a different focus, partly because neutrons being neutral means they’re very hard to accelerate.

There’s an ultra cold neutron source at Paul Scherrer that is used to measure if the neutron has an electric dipole moment. This is complementary to high energy experiments.

[antonvs]

Neutrons are not that different from protons. The decay from neutrons to protons is pretty well understood, and there’s no reason to think that the nature of quark/gluon interactions in a neutron are significantly different from those in a proton. What kind of new physics are you imagining we’d get?

Of course more experimental data is a good thing, but in this case it doesn’t seem obvious that it would lead to anything really new.