Power Corrections and KLN Cancellations

Abstract

We consider perturbative expansions in theories with an infrared cutoff $\lambda$. The infrared sensitive pieces are defined as terms nonanalytic in the infinitesimal ${\lambda }^2$ and powers of this cutoff characterize the strength of these infrared contributions. It is argued that the sum over the initial and final degenerate ( as $\lambda \to 0$) states which is required by the Kinoshita - Lee - Nauenberg theorem eliminates terms of order ${\lambda }^0$ and ${\lambda }^1$. However, the quadratic and higher order terms in general do not cancel. This is investigated in simple examples of KLN cancellations, of relevance to the inclusive decay rate of a heavy particle, at the one loop level.

20 pages, LaTeX

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Cited by in corpus (4)

• Renormalons
• Linear power corrections to single top production processes at the LHC
• Cancellation of $1/m_Q$ Corrections to the Inclusive Decay Width of a Heavy Quark
• The static PQCD potential with modified boundary conditions