Abstract
We evaluate a 1-loop, 2-point, massless Feynman integral ID,m(p,q) relevant for perturbative field theoretic calculations in strongly anisotropic d=D+m dimensional spaces given by the direct sum RD ⨁ Rm . Our results are valid in the whole convergence region of the integral for generic (noninteger) codimensions D and m. We obtain series expansions of ID,m(p,q) in terms of powers of the variable X:=4p2/q4, where p=|p|, q=|q|, p Є RD, q Є Rm, and in terms of generalised hypergeometric functions 3F2(−X), when X<1. These are subsequently analytically continued to the complementary region X≥1. The asymptotic expansion in inverse powers of X1/2 is derived. The correctness of the results is supported by agreement with previously known special cases and extensive numerical calculations.
| Original language | English |
|---|---|
| Pages (from-to) | 2220-2246 |
| Number of pages | 26 |
| Journal | Mathematical Methods in the Applied Sciences |
| Volume | 41 |
| Issue number | 5 |
| Early online date | 7 Feb 2018 |
| DOIs | |
| Publication status | Published - 30 Mar 2018 |
Keywords
- Analytic continuation
- Asymptotic expansions
- Feynman integrals and graphs
- Hypergeometric functions
- Lifshitz point
- Lorentz-violating theory