Tagged Questions
2
votes
1answer
129 views
SU(3) gauge invariance in QCD
In QCD, the gauge-invariant lagrangian under the trasformation
$ \psi \to \psi' = e^{ig T^a \theta^a(x)} \psi$
is written as:
$\mathcal{L} = \bar{\psi}(i\gamma^\mu D_\mu - m)\psi - ...
0
votes
1answer
115 views
In a gauge theory, are two states related by a global phase transformation identified?
In a gauge theory (non-abelian for this question), I am told that two states $|\psi\rangle$ and $|\phi\rangle$ are to be identified if they are related by a gauge transformation $U(x)$
...
3
votes
0answers
132 views
Gauge invariance of gg->gg scattering amplitude?
I'm trying to calculate the spin and color averaged gg->gg cross section, and I am stumbling upon gauge invariance:
Must the amplitude not be invariant under replacements $\epsilon_i \to \epsilon_i + ...
