Arithmetic and geometry of a K3 surface emerging from virtual corrections to Drell--Yan scattering
Marco Besier, Dino Festi, Michael Harrison, Bartosz Naskrecki
TL;DR
The paper resolves a key geometric question arising from two-loop EW–QCD corrections to Drell--Yan scattering by showing the associated hypersurface $X_{DY}$ is birational to a K3 surface with a rich Picard lattice: $\rho(\overline{S})=19$, $\operatorname{disc}(\operatorname{Pic}(\overline{S}))=24$, and discriminant group $(\mathbb{Z}/2\mathbb{Z})^2\times(\mathbb{Z}/6\mathbb{Z})$. It provides two independent computations of the Picard lattice, constructs an explicit Shioda--Inose structure connecting the K3 surface to a pair of elliptic curves, and analyzes the elliptic fibrations and their Mordell--Weil groups to obtain a concrete $\mathrm{NS}(\overline{S})$ basis. The work further computes the Brauer group, discusses supersingular reductions, and presents a second, fibrational route to the Picard lattice, including a detailed height-pairing analysis and a discriminant computation that culminates in a transparent lattice decomposition $N= L\oplus U$ with $\operatorname{disc}(L)=-24$ and $\operatorname{disc}(U)=-1$. These results illuminate the interplay between perturbative quantum-field-theory integrals and algebraic geometry, offering a pathway to express Drell--Yan master integrals via elliptic or modular structures. Overall, the paper advances both the mathematical understanding of K3 surfaces arising from physics-inspired square roots and the potential for applying elliptic-fibration methods to high-precision Feynman integral computations.
Abstract
We study a K3 surface, which appears in the two-loop mixed electroweak-quantum chromodynamic virtual corrections to Drell--Yan scattering. A detailed analysis of the geometric Picard lattice is presented, computing its rank and discriminant in two independent ways: first using explicit divisors on the surface and then using an explicit elliptic fibration. We also study in detail the elliptic fibrations of the surface and use them to provide an explicit Shioda--Inose structure. Moreover, we point out the physical relevance of our results.
