In the remainder of this section we investigate the extent to which different F - theory GUTs generate distinguishable experimental signatures . To this end , in subsection 4.1 we first list candidate signatures of interest which have strong dependence on the parameters of F - theory GUTs . Using these signatures , we compute the corresponding value of ∆S 2 between a fixed " LHC point " and various F - theory GUTs . In particular , we show that this type of analysis is capable of determining both N 5 and Λ , and moreover , can distinguish between scenarios with small and large PQ deformation . Restricting to the case of single messenger F - theory GUTs and a particular value of Λ , we next compute the value of ∆S 2 between models with different values of ∆ P Q . We find that at 5 fb −1 of simulated data , ∆ P Q can be determined up to an uncertainty of ∼ ±80 GeV , while at 50 fb −1 , this improves to an uncertainty of ∼ ±10 GeV. In particular , this shows that the LHC is indeed sensitive , albeit indirectly , to string scale physics ! Finally , although outside the main focus of this paper , in Appendix E we consider the sensitivity of the endpoint of the ditau invariant mass distribution as a function of ∆ P Q .