Multiplicative Bessel Kernels: from addition laws to CY periods

We discuss few very recent results of a work in progress (in collaboration with I. Gaiur and D. Van Straten) about interesting properties of multiplicative Bessel kernels, which includes well-known Clausen and Sonin-Gegenbauer formulae of XIX century, special examples of Kontsevich discriminant loci polynomials, raised as addition laws for special two-valued formal groups (Buchshtaber-Novikov) and period functions for CY and Landau–Ginzburg models.