Bounding CKM Mixing with a Fourth Family
نویسنده
چکیده
CKM mixing between third family quarks and a possible fourth family is constrained by global fits to the precision electroweak data. The dominant constraint is from nondecoupling oblique corrections rather than the vertex correction to Z → bb used in previous analyses. The possibility of large mixing suggested by some recent analyses of FCNC processes is excluded, but 3-4 mixing of the same order as the Cabbibo mixing of the first two families is allowed. ar X iv :0 90 4. 35 70 v1 [ he pph ] 2 2 A pr 2 00 9
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