How much space is left for a new family of fermions?

Bobrowski, M.; Lenz, A.; Riedl, J.; Rohrwild, J.

Abstract

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 3×3 Cabibbo-Kobayashi-Maskawa (CKM) elements and flavor-changing neutral current (FCNC) processes (K, D, Bd, Bs mixing and the decay b→sγ) under the assumption that the 4×4 CKM matrix is unitary. For the FCNCs we use some simplifying assumptions concerning the QCD corrections. Typically small mixing with the fourth family is favored; contrary to expectation, however, we find that also a quite large mixing with the fourth family is not yet excluded.

Citation

Bobrowski, M., Lenz, A., Riedl, J., & Rohrwild, J. (2009). How much space is left for a new family of fermions?. Physical Review D, 79(11), Article 113006. https://doi.org/10.1103/physrevd.79.113006

• Journal Article Type: Article
• Publication Date: 2009-06
• Deposit Date: Nov 19, 2012
• Journal: Physical Review D
• Print ISSN: 1550-7998
• Electronic ISSN: 1550-2368
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 79
• Issue: 11
• Article Number: 113006
• DOI: https://doi.org/10.1103/physrevd.79.113006