GKZ-system of the 2-loop self energy with 4 propagators

Applying the system of linear partial differential equations derived from Mellin-Barnes representations and Miller's transformation, we present GKZ-system of Feynman integral of the 2-loop self energy diagram with 4 propagators. The codimension of derived GKZ-system equals the number of independent dimensionless ratios among the external momentum squared and virtual mass squared. In total 536 hypergeometric functions are obtained in neighborhoods of origin and infinity, in which 30 linearly independent hypergeometric functions whose convergent regions have non-empty intersection constitute a fundamental solution system in a proper subset of the whole parameter space.Comment: latex, 299 pages, including 1 figure + 17 appendices. arXiv admin note: text overlap with arXiv:2206.0422