HADES in Nature Physics
"Results from the HADES experiment with direct contribution from LIP published in the Nature Physics journal report the measurement of the properties of a state of matter similar to the one arising from the merge of two neutron stars"
Visible matter in the universe arose when hadrons (the constituents of atomic nuclei) formed from a hot, dense fireball formed by quarks and gluons. This state of matter, which existed about 10 microseconds after the Big Bang, can be recreated in the laboratory in heavy nuclei collisions.
The HADES experiment has studied the properties of this primordial state of matter in collisions of gold nuclei at an energy of 2.42 GeV. The fireball formed in the collision only exists for a very short time, rapidly giving rise to a large number of hadrons. But it also emits photons, which are not affected by the strong force and thus cross this state of matter bringing us information about its interior. They are detected in HADES after being converted into an electron-positron pair.
In the article now published in Nature Physics, with direct contribution from the LIP group, the HADES collaboration presents the measurement of the properties of electron-positron pairs originated by this mechanism in gold-gold collisions. They measure a state of matter similar to that arising from the merge of two neutron stars, but with spectral properties similar to those of the early universe.
The article can be found here
Quanta Magazine article here