Extremal real-part zeros attained by fibred stable alternating knots

For $n\geq1$, let $\Gamma_{2n}$ be the set of Alexander polynomials of alternating knots of genus $n$, and let $\delta_{2n}$ be the maximum of the maximal real part of a zero among polynomials in $\Gamma_{2n}$. Extremal-attainment conjecture. The quantity $\delta_{2n}$ exists for every $n\geq1$, and there is a fibred stable alternating knot $K_n$ such that

$$\delta_{2n}(K_n)=\delta_{2n}.$$

This combines existence of the extremal value with the assertion that it is realized by a fibred stable alternating knot.