In this paper characters of the normaliser of $d$-split Levi subgroups in $\mathrm { SL}_n(q)$ and $\mathrm { SU}_n(q)$ are parametrized with a particular focus on the Clifford theory between the Levi subgroup and its normalizer.These results are applied to verify the Alperin-McKay conjecture for primes $\ell$ with $\ell\nmid 6(q^2-1)$ and the Alperin weight conjecture for $\ell$-blocks of those quasi-simple groups with abelian defect. The inductive Alperin-McKay condition and inductive Alperin weight condition by the second author are verified for certain blocks of $\mathrm { SL}_n(q)$ and $\mathrm { SU}_n(q)$.
Categories: math.RT math.GR