That experiment was conducted by Geiger and Marsden and disproved the plum-pudding model of the atom.
The STAR Collaboration reported the observation of this particle's antiparticle, the most massive antiparticle observed to date. George Gamow discovered the mechanism for the release of these particles via quantum tunnelling. This particle and a neutron are produced by the fusion of triton and deuteron particles. These particles followed a one over sine to the fourth scattering in an experiment in that detected them using a zinc sulfide screen. That experiment was conducted by Geiger and Marsden and disproved the plum-pudding model of the atom. For 10 points, name this particle used in Rutherford's gold foil experiment, which is identical to a helium-4 nucleus.
The STAR Collaboration reported the observation of this particle's antiparticle, the most massive antiparticle observed to date.
alpha particle [accept helium nucleus until said]