Early LHC phenomenology of Yukawa-bound heavy QQ? mesons
Journal
Physical Review D - Particles, Fields, Gravitation and Cosmology
Journal Volume
84
Journal Issue
9
Date Issued
2011
Author(s)
Abstract
Current limits from the LHC on fourth generation quarks are already at the unitarity bound of 500GeV or so. If they exist, the strong Yukawa couplings are turning nonperturbative, and may form bound states. We study the domain of mb′ and mt′ in the range of 500 to 700GeV, where we expect binding energies are mainly of Yukawa origin, with QCD subdominant. To be consistent with electroweak precision tests, the t ′ and b′ quarks have to be nearly degenerate, exhibiting a new "isospin." Comparing relativistic expansion with a relativistic bound state approach, we find the most interesting is the production of a color octet, isosinglet vector meson (a "gluon-prime") via qq̄→ω8. Leading decay modes are π8±W, π80Z0, and constituent quark decay, with qq̄ and tt ̄′ and bb̄′ subdominant. The color octet, isovector pseudoscalar π8 meson decays via constituent quark decay, or to Wg. These decay rates are parameterized by the decay constant, the binding energy and mass differences, and Vtb′. For small Vt′b, one could have a spectacular signal of WWg, where a soft W accompanies a very massive Wg pair. In general, however, one has high multiplicity signals with b, W, and t jet substructures that are not so different from the t′t ̄′ and b′b ̄′ search. © 2011 American Physical Society.
SDGs
Type
journal article