Renormalon

In physics, a renormalon (a term suggested by 't Hooft[1]) is a particular source of divergence seen in perturbative approximations to quantum field theories (QFT). When a formally divergent series in a QFT is summed using Borel summation, the associated Borel transform of the series can have singularities as a function of the complex transform parameter.[2] The renormalon is a possible type of singularity arising in this complex Borel plane, and is a counterpart of an instanton singularity. Associated with such singularities, renormalon contributions are discussed in the context of quantum chromodynamics (QCD)[2] and usually have the power-like form as functions of the momentum (here is the momentum cut-off). They are cited against the usual logarithmic effects like .

  1. ^ 't Hooft G, in: The whys of subnuclear physics (Erice, 1977), ed. A Zichichi, Plenum Press, New York, 1979.
  2. ^ a b Beneke, M. (August 1999). "Renormalons". Physics Reports. 37 (1–2): 1–142. arXiv:hep-ph/9807443. Bibcode:1999PhR...317....1B. doi:10.1016/S0370-1573(98)00130-6.