Luthe, Thomas: Fully massive vacuum integrals at 5 loops. 2015
Inhalt
- Introduction and motivation
- Reduction to master integrals
- Notation
- Momentum shifts
- Linear relations between integrals
- Integration by parts
- Syzygies
- Mass derivatives and Lorentz invariance
- Relations between different dimensions
- Reduction
- Example: 4-loop sunset
- Solving master integrals
- Feynman parameters
- Sector decomposition
- Parametric integration and linear reducibility
- Mellin-Barnes representations
- Differential equations
- Dimensional recurrence relations
- Laporta's method
- Difference equations
- Laporta's algorithm for difference equations
- Minimal order reduction algorithm
- Comparison of reduction algorithms
- Translation and recurrence relations
- Evaluation via factorial series
- Interlude: Fibonacci numbers
- The general solution
- Initial conditions
- Precision and convergence
- Numerical evaluation in practice
- Implementation details
- Reductions
- Momentum shifts
- Generation of equations and the r-s-boundaries
- Rational algebra and parallelisation
- Numerical runs and delayed subsector execution
- Choosing a master basis
- Timings
- Numerical evaluation
- The fully massive tadpoles up to 5 loops
- Conclusion and outlook
- Tadpole classification
- Reduction statistics
- Numerical results
- References
