Discovered in 1932 by James Chadwick, for 10 points, name this electrically neutral subatomic particle, found in the nucleus with protons.
Experiments by Francisco-Miguel Marqu? et al. suggested the possibility of a stable cluster of four of them.  Brockhouse developed a method of spectroscopy using these particles, and work leading to their discovery showed that beryllium rays could remove particles from paraffin wax and was performed by the Joliot-Curies.  An antineutrino is released when these undergo a certain type of decay, and free ones have a lifetime of approximately fifteen minutes.  They undergo beta-minus decay, and are created by electron capture.  Discovered in 1932 by James Chadwick, for 10 points, name this electrically neutral subatomic particle, found in the nucleus with protons.
Experiments by Francisco-Miguel Marqu? et al. suggested the possibility of a stable cluster of four of them.  
neutrons