TY - JOUR

T1 - Effective Field Theories

AU - Grozin, Andrey

PY - 2020/6

Y1 - 2020/6

N2 - This paper represents a pedagogical introduction to low-energy effective field theories. In some of them, heavy particles are "integrated out" (a typical example-the Heisenberg-Euler EFT); in some, heavy particles remain but some of their degrees of freedom are "integrated out" (Bloch-Nordsieck EFT). A large part of these lectures is, technically, in the framework of QED. QCD examples, namely decoupling of heavy flavors and HQET, are discussed only briefly. However, effective field theories of QCD are very similar to the QED case, and there are just some small technical complications: more diagrams, color factors, etc. The method of regions provides an alternative view at low-energy effective theories; this is also briefly introduced.

AB - This paper represents a pedagogical introduction to low-energy effective field theories. In some of them, heavy particles are "integrated out" (a typical example-the Heisenberg-Euler EFT); in some, heavy particles remain but some of their degrees of freedom are "integrated out" (Bloch-Nordsieck EFT). A large part of these lectures is, technically, in the framework of QED. QCD examples, namely decoupling of heavy flavors and HQET, are discussed only briefly. However, effective field theories of QCD are very similar to the QED case, and there are just some small technical complications: more diagrams, color factors, etc. The method of regions provides an alternative view at low-energy effective theories; this is also briefly introduced.

KW - HQET

KW - decoupling

KW - HEAVY QUARKS

KW - INVARIANCE

U2 - 10.3390/particles3020020

DO - 10.3390/particles3020020

M3 - Review article

VL - 3

SP - 245

EP - 271

JO - Particles

JF - Particles

SN - 2571-712X

IS - 2

ER -