Proton decay testing low energy SUSY

We show that gauge coupling unification in SUSY models can make a non-trivial interconnection between collider and proton decay experiments. Under the assumption of precise gauge coupling unification in the MSSM, the low energy SUSY spectrum and the unification scale are intertwined, and the lower bound on the proton lifetime can be translated into upper bounds on SUSY masses. We found that the current limit on $\tau(p \to \pi^0 e^+)$ already excludes gluinos and winos heavier than $\sim 120$ and 40 TeV, respectively, if their mass ratio is $M_3/M_2 \sim 3$. Next generation nucleon decay experiments are expected to bring these upper bounds down to $\sim 10$ and 3 TeV.