Hi,
1: I just want to ask that what does SU(3) x SU(2) x U(1) means?
and when a lagrangian is invariant under SU(3) x SU(2) x U(1)
what does that mean?
Does it mean that lagrangian L is invariant under SU(3) and then SU(2) and
then U(1)? so if one wants to check SU(3) invariance of L...