Differential equations for loop integrals without squared propagators

Understand

We provide a sufficient condition for avoiding squared propagators in the intermediate stages of setting up differential equations for loop integrals.

• This condition is satisfied in a large class of two- and three-loop diagrams.
• For these diagrams, the differential equations can thus be computed using "unitarity-compatible" integration-by-parts reductions, which simplify the reduction problem by avoiding integrals with higher-power propagators.