Helium-4 (4 He ) is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up...

nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why...

Superfluid helium-4 (helium II or He-II) is the superfluid form of helium-4, an isotope of the element helium. A superfluid is a state of matter in which...

Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures. Liquid helium may show superfluidity. At standard...

there are nine known isotopes of helium (2He) (standard atomic weight: 4.002602(2)), only helium-3 (3 He ) and helium-4 (4 He ) are stable. All radioisotopes...

Helium-3 (3He see also helion) is a light, stable isotope of helium with two protons and one neutron (in contrast, the most common isotope, helium-4 has...

protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay but...

universe's helium (as isotope helium-4 (4He)), along with small fractions of the hydrogen isotope deuterium (2H or D), the helium isotope helium-3 (3He)...

include the photon and atoms with an even number of neutrons (such as helium-4 (4 He )), are allowed to share a quantum state. Einstein proposed that cooling...

nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon. Helium accumulates in the cores of stars as a result...