We show how the topological susceptibility in the Minkowskian theory of QCD is related to the corresponding quantity in Euclidean theory, which is measured on the lattice. We discuss both the zero-temperature case (T = 0) and the finite-temperature case (T not equal 0). It is shown that the two quantities are equal when T = 0, while the relation between them is much less trivial when T not equal 0. The possible existence of "Kogut-Susskind poles'' in the matrix elements of the topological charge density between states with equal four-momenta turns out to invalidate the equality of these two quantities in a strict sense. However, an equality relation is recovered after one redefines the Minkowskian topological susceptibility by using a proper infrared regularization. [S0556-2821(98)04918-2].
|Autori interni:||MEGGIOLARO, ENRICO|
|Titolo:||Topological susceptibility of QCD: From Minkowskian to Euclidean theory|
|Anno del prodotto:||1998|
|Digital Object Identifier (DOI):||10.1103/PhysRevD.58.085002|
|Appare nelle tipologie:||1.1 Articolo in rivista|