The three LHC-experiments (ALICE, ATLAS and CMS), which study lead-collisions have presented their latest results at the international Quark Matter 2011 conference, held in Annecy in France with over 750 participants from all over the world. The results are based on the analysis of new data from November-December 2010, when the LHC collided lead ions at approximately 14 times higher energy than was previously possible. ...
Dense as a neutron star but much, much hotter
The results from the ALICE experiment have provided evidence that the matter formed in the lead ion collisions is the densest ever observed. It is denser than a neutron star and over 100,000 times hotter than the interior of the Sun.
"These conditions make it possible to study the properties of the primordial soup in unprecedented detail. ALICE has confirmed the results of the RHIC experiments, which show that a quark-gluon-plasma behaves like a viscous liquid”, explains professor Jens Jørgen Gaardhøje, leader of the ALICE group at the Discovery Center at the Niels Bohr Institute. ...
The measurements suggest that the universe was close to an ‘ideal’ liquid and now numbers could be put on how dense. The values can be compared with predictions of string theory, which predict that ‘inertia’ (the viscosity) is the lowest possible attainable.