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Institute for Advanced Simulation (IAS)

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Selected results of the SimLab Nuclear & Particle Physics

Freeze-out parameters from Lattice QCD

Building on our precision calculation of the fluctuations of conserved charges in heavy ion experiments, we were able to extract the freeze-out paramters, i.e. temperature and chemical potential, from first principles using Lattice QCD.

QCD and QED and the stability of matter

In 2013, we extended our spectrum calculations by including QED in the valence sector. While QED effects are small, the interplay between isospin splitting in QCD and QED effects results in the uncharged neutron being heavier than the hydrogen nucleus, the proton, rendering the latter, and thus ordinary matter, stable.

Building on this experience, we performed a new set of simulations in 2014, using a new action that included QED in the sea sector as well. This result achieved a much higher precision for the neutron-proton mass splitting, excluding zero by more than 5 standard deviations.

Quark masses and physical point

In 2011, we were the first to reach the physical point using the theoretically clean Wilson-Clover discretization of Lattice QCD. This allowed us to extract the light quark masses with high precision, improving on the then available PDG value by almost an order of magnitude.

Spectrum of QCD

In 2008, we computed the low lying hadron masses from first principles using Lattice QCD. Our result was later selected by Science as one of the Top-10 Scientific breakthroughs of 2008.