Branching Rules for $n$-fold Covering Groups of $\mathrm{SL}_2$ over a   Non-Archimedean Local Field
  Let $\widetilde{G}$ be the $n$-fold covering group of the special linear group of degree two, over a non-Archimedean local field. We determine the decomposition into irreducibles of the restriction of the principal series representations of $\widetilde{G}$ to a maximal compact subgroup of $\widetilde{G}$. 
Camelia Karimianpour
math.RT