Applied Asymptotic Expansions in Momenta and Masses / Edition 1

by Vladimir A. Smirnov

Overview

'The sturgeon they sent was second grade fresh,' said the barman. 'Really, what nonsense/' 'Why nonsense?' '"Second grade fresh" that's what I call nonsense/ There's only one degree of freshness the first, and it's the last) (M. A. Bulgakov, The Master and Margarita) The goal of this book is to describe in detail how Feynman integrals can be expanded in suitable parameters, when various momenta or masses are small or large. In a narrow sense, this problem is connected with practical calcula tions. In a situation where a given Feynman integral depends on parameters of very different scales, a natural idea is to replace it by a sufficiently large number of terms of an expansion of it in ratios of small and large scales. It will be explained how this problem of expansion can be systematically solved, by formulating universal prescriptions that express terms of the expansion by using the original Feynman integral with its integrand expanded into a Taylor series in appropriate momenta and masses. It turns out that knowledge of the structure of the asymptotic expansion at the diagrammatic level is a key point in understanding how to perform expansions at the operator level. There are various examples of these ex pansions: the operator product expansion, the large mass expansion, Heavy Quark Effective Theory, Non Relativistic QCD, etc. Each of them serves as a realization of the factorization of contributions of different scales.

Product Details

ISBN-13:	9783642076121
Publisher:	Springer Berlin Heidelberg
Publication date:	12/03/2010
Series:	Springer Tracts in Modern Physics , #177
Edition description:	Softcover reprint of hardcover 1st ed. 2002
Pages:	265
Product dimensions:	6.10(w) x 9.25(h) x 0.24(d)

Table of Contents

Feynman Integrals: a Brief Review.- Why, Where and How to Expand.- Off-Shell Large-Momentum Expansion.- Large-Mass Expansion.- Threshold Expansion. One Heavy Mass in the Threshold.- Threshold Expansion. Two Masses in the Threshold.- Sudakov Limits.- Conclusion.- Tables.- Technical Details: Convergence and Asymptotic Behaviour.