---
address: |
    Centre de Physique Théorique\
    CNRS-Luminy, Case 907\
    F-13288 Marseille Cedex 9, France[^1]
author:
- Eduardo de Rafael
---

An Introduction to Sum Rules in QCD 
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Introduction
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These lectures are an introduction to the subject of sum rules in hadronic interactions as understood at present within the framework of quantum chromodynamics (QCD). The literature on the subject is extensive and various applications are quoted in other lectures at this school. I have chosen to concentrate on the foundations of the subject rather than giving an exhaustive list of results obtained from sum rules. The aim is to give you a critical overview of the subject so that you can judge by yourselves on how seriously to take the results in the literature, and also to foresee which possible new applications could be made. One often encounters two extreme attitudes among theorists on results obtained using QCD sum rules. One is the optimistic belief that the result can be trusted at the few percent level, when in fact there are a host of assumptions in the derivation; the other is the pessimistic attitude which pretends that all QCD sum rules are “wrong” because some calculation somebody made 