During the decay of this particle, one of its two down quarks is converted to an up quark via the weak interaction.
Bertram Brockhouse won the Nobel Prize in Physics for his work on scattering of and spectroscopy with this type of particle, including his work on a triple-axis spectrometer. Analysis of elements such as hydrogen, boron, carbon, and nitrogen can be conducted with prompt gamma ray activation analysis, which uses a beam of these particles. A related technique allows nondestructive testing for mass fractions of up to 40 elements in a material. During the decay of this particle, one of its two down quarks is converted to an up quark via the weak interaction. Their existence was first posited in an effort to explain the results of alpha particle collisions with beryllium-9 and the subsequent radiation produced. First suggested by James Chadwick, for 10 points, name this component of the nucleus which has no charge. 
Bertram Brockhouse won the Nobel Prize in Physics for his work on scattering of and spectroscopy with this type of particle, including his work on a triple-axis spectrometer.
neutron