Unlike in the Standard Model, in the minimal supersymmetric extension of the Standard Model (MSSM) the Higgs boson mass is not a free parameter; it can be calculated given all masses and couplings of the supersymmetric particles. At the lowest order, it is equal to the Z bosons mass 91 GeV (for large enough tanβ). To reconcile the predicted and the observed Higgs mass, one needs to invoke large loop corrections due to supersymmetry breaking. These are dominated by the contribution of the top quark and its 2 scalar partners (stops) which couple most strongly of all particles to the Higgs. As can be seen in the plot above, the stop mass preferred by the Higgs mass measurement is around 10 TeV. With a little bit of conspiracy, if the mixing between the two stops is just right, this can be lowered to about 2 TeV. In any case, this means that, as long as the MSSM is the correct theory, there is little chance to discover the stops at the LHC.
This conclusion may be surprising because previous calculations were painting a more optimistic picture. The results above are derived with the new SUSYHD code, which utilizes effective field theory techniques to compute the Higgs mass in the presence of heavy supersymmetric particles. Other frequently used codes, such as FeynHiggs or Suspect, obtain a significantly larger Higgs mass for the same supersymmetric spectrum, especially near the maximal mixing point. The difference can be clearly seen in the plot to the right (called the boobs plot by some experts). Although there is a debate about the size of the error as estimated by SUSYHD, other effective theory calculations report the same central values.