Gravity affects neutrons

Question

A long time ago I asked whether gravity affected subatomic particles. An experimental physicist kindly explained that it's known to affect neutrons. Get a neutron source, and send a beam of neutrons horizontally. The slower neutrons fall farther in a given distance.

That doesn't tell us whether gravity affects charged particles, but it's plausible it would and their charges make the effect of gravity so small that it's hard to detect.

Does gravity affect all neutrons equally?

Suppose there's some neutron quality that results in neutrons that are not affected by gravity, or affected less. Then slow neutrons that ARE affected by gravity would fall, and the lower neutrons would be enriched for them.

Say for example that neutrons that spin on one axis are affected by gravity, and neutrons that spin pn another axis are not. Then if you start with neutrons spinning in all directions, they would be smeared out according to their spins. And it would work the same with anything that changed gravity's effect.

Also, if you could suddenly cut off the source of neutrons, then if they are all affected equally, the last slow neutrons would arrive later, after all the fast neutrons are gone and they would all be low. If there are slow neutrons that do not fall, then the late neutrons would be spread out.

Have these experiments been done? Is it known whether all neutrons are equally affected by gravity?

Answer 1

Have these experiments been done?

Here is an experiment,

Newton’s law of universal gravitation predicts that the gravitational force between two objects is proportional to the objects’ masses and inversely proportional to the square of the distance between them. The law, which applies to weakly interacting objects traveling at speeds much slower than that of light, has survived test after test. However, some quantum gravity theories anticipate that the law might break down at small distances

italics mine for stressing the point.

they

have checked Newton’s law on subnanometer scales. So far, the team has found no deviations from Newtonian predictions.

Is it known whether all neutrons are equally affected by gravity?

Neutrons, in mainstream physics which is discussed on this site, are quantum mechanical entities, and in quantum mechanics one neutron is indistinguishable from another, i.e. the neutrons in the pulsed neutron beam for the experiment linked above are considered to have the same quantum numbers and energy/momentum obeying the same boundary conditions. Deviations from this, i.e width of momentum distribution etc will enter into the error given by the experiment.

The team is currently upgrading the setup to reduce sources of noise and envisions achieving order-of-magnitude sensitivity improvements in the near future.