Large muon $(g-2)$ with TeV-scale SUSY masses for $\tan\beta\to\infty$

The muon anomalous magnetic moment $a_\mu$ is investigated in the MSSM for $\tan\beta\to\infty$. This is an attractive example of radiative muon mass generation with completely different qualitative parameter dependence compared to the MSSM with the usual, finite $\tan\beta$. The observed, positive difference between the experimental and Standard Model value can only be explained if there are mass splittings, such that bino contributions dominate over wino ones. The two most promising cases are characterized either by large Higgsino mass $\mu$ or by large left-handed smuon mass $m_L$. The required mass splittings and the resulting $a_\mu^\text{SUSY}$ are studied in detail. It is shown that the current discrepancy in $a_\mu$ can be explained even in cases where all SUSY masses are at the TeV scale. The paper also presents useful analytical formulas, approximations for limiting cases, and benchmark points.