Advances in High Energy Physics / 2013 / Article / Fig 3

Review Article

Constraints on a Fourth Generation of Fermions from Higgs Boson Searches

Figure 3

Allowed mass splitting of fourth generation quarks according to the constraints from electroweak precision observables. (a) CKM mixing is forced to be zero, (b) it is allowed to an extent that does not violate any bound from flavor physics. For both pictures the lepton masses were fixed.