Approaching a strong fourth family

Abstract

A heavy fourth family is an example of new physics which is well defined and familiar in some respects, but which nevertheless has radical implications. In particular it eliminates a light Higgs description of electroweak symmetry breaking. We discuss an early signal for heavy quarks at the LHC in the form of an excess of "$W$-jets", and as well show how $W$-jets may be useful in the reconstruction of the heavy quark masses. We argue that fourth family quarks can be distinguished from vector-like quarks of a similar mass at roughly the same time that a same sign lepton signal becomes visible. Given the large mass of the fourth neutrino we describe how a picture for neutrino mass emerges in the absence of right-handed neutrinos, and how it suggests the existence of a remnant flavor gauge symmetry. Based on talk given at "Second Workshop on Beyond 3 Generation Standard Model -- New Fermions at the Crossroads of Tevatron and LHC", January 2010, Taipei Taiwan.

14 pages, 10 figures, references added and slight changes

References in corpus (6)

• PYTHIA 6.4 Physics and Manual
• Updated predictions for the total production cross sections of top and of heavier quark pairs at the Tevatron and at the LHC
• The discovery of the fourth family at the LHC: what if?
• Using jet mass to discover vector quarks at the LHC
• The heavy quark search at the LHC
• New Flavor Interactions at the LHC

Cited by in corpus (6)

• Patterns of Flavour Violation in the Presence of a Fourth Generation of Quarks and Leptons
• A fourth generation, anomalous like-sign dimuon charge asymmetry and the LHC
• Fourth Generation Bound States
• Searches for the $t^{\prime }$ of a fourth family
• Three Extra Mirror or Sequential Families: a Case for Heavy Higgs and Inert Doublet
• Electroweak Symmetry Breaking From Monopole Condensation