We demonstrate that $\mu \leftrightarrow e$ slepton mixing is significantly more restricted than previously thought within the already remarkably flavor-safe $R$-symmetric supersymmetric standard model. We calculate bounds from $\mu \to e\gamma$, $\mu \to 3e$, and most importantly, $\mu \to e$ conversion. The process of $\mu \to e$ conversion is significantly more restrictive in $R$-symmetric models since this process can occur through operators that do not require a chirality flip. We delineate the allowed parameter space, demonstrating that maximal mixing is rarely possible with weak scale superpartners, while $\mathcal{O}(0.1)$ mixing is permitted within most of the space. The best approach to find or rule out $\mu \leftrightarrow e$ mixing in $R$-symmetric supersymmetric models is a multipronged attack looking at both $\mu \to e$ conversion as well as $\mu \to e\gamma$. The redundancy eliminates much of the parameter space where one process, but not both processes, contains amplitudes that accidentally destructively interfere. We briefly discuss implications for searches of slepton flavor violation at the LHC.

• Received 14 April 2010

DOI:https://doi.org/10.1103/PhysRevD.82.035010