I have been reading the article Neutron Lifetime Puzzle Deepens, but No Dark Matter Seen on the present methods of measuring the life span of neutrons The bottle method measures a mean lifespan which is seconds shorter than the other the beam method. One explanation is that neutrons decay into dark matter, but it seems to me that this should be expected. We know that a faster particle like a neutron in a beam should, by special relativity, experience time slower than a particle that is moving slowly or standing still.
Is it possible that the difference between "bottle" and "beam" measurements of the neutron lifetime is due to relativity, since the "beam" neutrons are moving faster than the "bottle" neutrons? Or do these discrepancies persist when Relativity is taken into account and thus require another explanation?