How much space is left for a new family of fermions

  title={How much space is left for a new family of fermions},
  author={M. Bobrowski and A. Lenz and J. Riedl and J. Rohrwild},
  journal={Physical Review D},
We perform an exploratory study of the allowed parameter range for the CKM-like mixing of hypothetical quarks of a fourth generation. As experimental constraints we use the tree-level determinations of the 3x3 Cabibbo-Kobayashi-Maskawa (CKM) elements and flavor-changing neutral current (FCNC) processes (K, D, B{sub d}, B{sub s} mixing and the decay b{yields}s{gamma}) under the assumption that the 4x4 CKM matrix is unitary. For the FCNCs we use some simplifying assumptions concerning the QCD… Expand
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