GUT matter

GUT matter :
Spacetime arrives when supergravity separates into the combined nuclear forces (strong, weak,
electromagnetic) and gravitation. Matter makes its first appearance during this era as a composite form
called Grand Unified Theory or GUT matter. GUT matter is a combination of what will become leptons,
quarks and photons. In other words, it contains all the superpositions of future normal matter. But, during
the GUT era, it is too hot and violent for matter to survive in the form of leptons and quarks.
Why can't matter remain stable at this point in the Universe's evolution? This involves the concept of
equilibrium, the balance between particle creation and annihilation.

During pair production, energy is converted directly into mass in the form of a matter and anti-matter
particle pair. The simplest particles are, of course, leptons such as an electron/positron pair. However, in
high energy regimes, such as the early Universe, the conversion from energy to mass is unstable compared
to the more probable mass to energy conversion (because the created mass must be so high in mass to
match the energy used). In other words, when temperatures are high, matter is unstable and energy is
stable.
Any matter that forms in the early Universe quickly collides with other matter or energy and is converted
back into energy. The matter is in equilibrium with the surrounding energy and at this time the Universe is
energy or radiation-dominated.
The type of matter that is created is dependent on the energy of its surroundings. Since the temperatures are
so high in the early Universe, only very massive matter (= high energy) can form. However, massive
particles are also unstable particles. As the Universe expands and cools, more stable, less massive forms of
matter form.

As the Universe expands, matter is able to exist for longer periods of time without being broken down by
energy. Eventually quarks and leptons are free to combine and form protons, neutrons and atoms, the
ordinary matter of today.