 BO-3, spin fermion model is a minimal model for the quantum critical point, QCP, of iron-based superconductors and electron-doaked cup rates. This model has been studied extensively, but until now it was not possible to accurately determine the scaling exponents and functional form of the static and dynamic spin susceptibilities. Using a hybrid Monte Carlo, HMC, algorithm with an auto-tuning procedure, researchers were able to study unprecedentedly large systems of 80 by 80 sites. They found a strong violation of the Hertz-Millis form, contrary to all previous numerical results. Furthermore, their predictions can be directly tested with new transcattering experiments. Additionally, the HMC method they introduced is generic and can be used to study other fermionic models of quantum criticality, where there is a strong need to simulate large systems. This article was authored by Peter Luntz, Michael S. Elburgo and Michael Lindsay.