Earlier this year, a collaboration of researchers at RHIC reported the observation of antihyperhydrogen-4. This antimatter and hypernucleic atom consists of an antiproton, two antineutrons ...

Normal helium, which is 700,000 times more common than helium-3, is called helium-4 because it has two protons and two neutrons. Whereas helium-4 is a common product of the decay of radioactive ...

For example, a helium atom has an atomic mass of 4, but an atomic number (or positive charge) of 2. Since electrons have almost no mass, it seemed that something besides the protons in the nucleus ...