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

Journal Article · Mon Jun 01 00:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.79.113006· OSTI ID:21296426

Bobrowski, Markus; Lenz, Alexander; Riedl, Johann; Rohrwild, Juergen ^[1]

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1. Institut fuer Theoretische Physik, Universitaet Regensburg, D-93040 Regensburg (Germany)

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 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.

• OSTI ID: 21296426
• Journal Information: Physical Review. D, Particles Fields, Vol. 79, Issue 11; Other Information: DOI: 10.1103/PhysRevD.79.113006; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CORRECTIONS
FLAVOR MODEL
KOBAYASHI-MASKAWA MATRIX
MIXING
NEUTRAL CURRENTS
PARTICLE DECAY
QUANTUM CHROMODYNAMICS
QUARKS
SPACE