The neutron is a particle with no charge but with internal structure. Like a ball that looks smooth on the outside but has a complex filling inside. Scientists have long wanted to understand how electric and magnetic forces are distributed inside the neutron. To do this, you need to "feel" it — collide it with its antiparticle and see what happens.
At the VEPP-2000 collider in Novosibirsk, electrons are collided with positrons (their antiparticles). At sufficient energy, a pair is born: a neutron and an antineutron. They fly apart in different directions. The direction of the scattering depends on how the electric and magnetic parts of the neutron's internal structure relate to each other. By measuring the scattering angle of the antineutron, physicists calculated this ratio.
It turned out that in the studied energy range, the ratio of the electric and magnetic components of the neutron lies between 1.0 and 1.5. The average value is 1.21 with an uncertainty of 0.13. This means that the electric part is slightly stronger than the magnetic part. This behavior helps refine models of the neutron's internal structure.
The neutron is one of the building blocks of atomic nuclei. Understanding its internal structure is important for nuclear physics, astrophysics, and even for the search for new physics beyond the Standard Model.
A free neutron lives for only about 15 minutes before it decays into a proton, an electron, and an antineutrino.