Protons attract neutrons


Neutrons, like protons, belong to the baryons. A neutron is made up of an up quark and two down quarks. It is electrically neutral, so it is neither attracted nor distracted by other charges. Neutrons are located next to protons in the atomic nucleus and ensure that the atomic nucleus remains stable.

The mass of free neutrons is slightly larger than the proton mass. Free neutrons are therefore not stable. A free neutron decays into a proton, an electron and an antineutrino after about a quarter of an hour. This decay is called beta decay and is caused by the weak interaction.

Although the neutrons are unstable, they help keep atomic nuclei stable. Neutrons attract other neutrons and protons via the strong nuclear force, but as uncharged particles they do not repel each other due to the electrical force. The strong interaction in the atomic nucleus also prevents neutrons bound in the atomic nucleus from decaying. Beta decay only occurs in atomic nuclei in which the number of neutrons is so large that the atomic nucleus is more stable when it has one more proton and one less neutron.

Neutron beams

Neutron radiation can be generated in special research reactors, which can be used to study the structure of solids. The advantage of neutron beams is that they are not charged. This means that the charged electron shell is "invisible" to them and only the positions of the atomic nuclei are tested. Magnetic structures can also be examined with neutron radiation whose spin is aligned. A magnetic field is associated with the spin of the neutrons.

Question on the subject

Why do protons and neutrons weigh more than the sum of the quarks they contain?

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Last change: 04/05/2004