For 10 points, identify this particle that is found in the nucleus and makes up the atom along with neutrons and electrons.
This particle is theoretically predicted to decay into a neutral pion and a positron, but this has never been experimentally observed; however, it can undergo the inverse beta decay by capturing an electron. They make up 90% of cosmic rays and contain two up quarks and one down quark, which makes them lighter than the other particle that, with it, makes up the alpha particle. Also known as the hydrogen ion, its number in an element is the atomic number. For 10 points, identify this particle that is found in the nucleus and makes up the atom along with neutrons and electrons.
This particle is theoretically predicted to decay into a neutral pion and a positron, but this has never been experimentally observed; however, it can undergo the inverse beta decay by capturing an electron.
protons