Early LHC Phenomenology of Yukawa-bound Heavy Q\bar{Q} Mesons

Abstract

Current limits from the LHC on fourth generation quarks are already at the unitarity bound of 500 GeV or so. If they exist, the strong Yukawa couplings are turning nonperturbative, and may form bound states. We study the domain of m_{b'} and m_{t'} in the range of 500 to 700 GeV, 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 q\bar{q} to ω_8. Leading decay modes are π_8^\pm W^\mp, π_8^0Z^0, and constituent quark decay, with q\bar{q} and t\bar{t}' and b\bar{b}' subdominant. The color octet, isovector pseudoscalar π_8 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 V_{tb'}. For small V_{t'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 t'\bar{t}' and b'\bar{b}' search.

14 pages, 12 figures; references added

References in corpus (3)

• Invariant Mass Distribution of Jet Pairs Produced in Association with a W boson in ppbar Collisions at sqrt(s) = 1.96 TeV
• Bounds on an anomalous dijet resonance in W+jets production in ppbar collisions at sqrt{s} =1.96 TeV
• Fourth Generation Bound States

Cited by in corpus (10)

• Closing in on a perturbative fourth generation
• Scalar leptoquarks and Higgs pair production at the LHC
• Bound States via Higgs Exchanging and Resonant Di-Higgs
• Status of the Fourth Generation - A Brief Summary of B3SM-III Workshop in Four Parts
• Electroweak Constraints on the Fourth Generation at Two Loop Order
• Hints for a Low Bs --> mu+ mu- Rate and the Fourth Generation
• Heavy QQ(bar) "Fireball" Annihilation to Multiple Vector Bosons
• Doubly resonant WW plus jet signatures at the LHC
• Decays of Fourth Generation Bound States
• Colour-octet bound states, induced by Higgs mechanism