Let $A$ be a simple abelian variety of dimension $g$. Let $K$ be an irreducible perverse sheaf on $A$. We know that $\chi(A,K)\geq 0$. (Corollary 1.4 of Franecki and Kapranov.) How small can $\chi(A,K)$ be?
There are some trivial examples. If $K$ is a lisse sheaf on all of $A$ placed in degree $g$, then $\chi(A,K)=0$. If $K$ is a skyscraper sheaf, then $\chi(A,K)=1$.
Beyond these trivial examples, if $A$ is the Jacobian of a curve $C$ of genus $g$ and $K$ is the constant sheaf on $C$, placed in degree $-1$ and pushed forward to $A$, then $\chi(A,K)=2g-2$.
I want to know if there is any nontrivial example with smaller Euler characteristic:
Does there exist a simple abelian variety $A$ of dimension $g$ and an irreducible perverse sheaf $K$ on $A$ such that $K$ is not lisse, $K$ is not a skyscraper sheaf, and $\chi(A,K)<2g-2$?
We know every irreducible perverse sheaf of Euler characteristic $0$ or $1$ is trivial in this sense. (Proposition 10.1 of Kramer and Weissauer.) So it is equivalent to ask:
Does there exist a simple abelian variety $A$ of dimension $g$ and an irreducible perverse sheaf $K$ on $A$ such that $2 \leq \chi(A,K) <2g-2?$
One way to construct a perverse sheaf on an abelian variety is to take a smooth variety $X$ and a finite morphism $f: X\to A$ and pushforward the constant sheaf in degree $-\dim(X)$ along $f$. So a subquestion is:
Does there exist a simple abelian variety $A$ of dimension $g$, a smooth non-abelian variety $X$ of dimension $d$, and a finite map $f:X \to A$, such that $(-1)^{d} \chi(X) < 2g-2$?