# Seminários

## Event

Title:
Prof. Daniel Zwanziger - NYU
When:
29.07.2010 14.30 h
Where:
Física Teórica -
Category:
Seminários

## Description

Título: Goldstone bosons and fermions in QCD

Resumo: We consider the version of QCD in Euclidean Landau gauge in which the restriction to the Gribov region is implemented by a local, renormalizable action. This action depends on the Gribov parameter $\gamma$, with dimensions of (mass)$^4$, whose value is fixed in terms of $\Lambda_{QCD}$, by the gap equation, known as the horizon condition, ${\p \Gamma \over \p \gamma} = 0$, where $\Gamma$ is the quantum effective action. The restriction to the Gribov region suppresses gluons in the infrared, which nicely explains why gluons are not in the physical spectrum, but this only makes makes more mysterious the origin of the long-range force between quarks. In the present article we exhibit the symmetries of $\Gamma$, and show that the solution to the gap equation, which defines the classical vacuum, spontaneously breaks some of the symmetries $\Gamma$. This implies the existence of massless Goldstone bosons and fermions that do not appear in the physical spectrum. Some of the Goldstone bosons may be exchanged between quarks, and are candidates for a long-range confining force. As an exact result we also find that in the infrared limit the gluon propagator vanishes like $k^2$.

Horário: 14:30.

Local: Sala 201.

Group:
Física Teórica

## Description

Grupo de Física Teórica do Instituto de Física - UFF.

### Calendários

<<  Oct 19  >>
Su  Mo  Tu  We  Th  Fr  Sa
1  2  3  4  5
6  7  8  9101112
13141516171819
202123242526
2728293031