Top condensation as a motivated explanation of the top forward-backward asymmetry

Abstract

Models of top condensation can provide both a compelling solution to the hierarchy problem as well as an explanation of why the top-quark mass is large. The spectrum of such models, in particular topcolor-assisted technicolor, includes top-pions, top-rhos and the top-Higgs, all of which can easily have large top-charm or top-up couplings. Large top-up couplings in particular would lead to a top forward-backward asymmetry through t-channel exchange, easily consistent with the Tevatron measurements. Intriguingly, there is destructive interference between the topmesons and the standard model which conspire to make the overall top pair production rate consistent with the standard model. The rate for same-sign top production is also small due to destructive interference between the neutral top-pion and the top-Higgs. Flavor physics is under control because new physics is mostly confined to the top quark. In this way, top condensation can explain the asymmetry and be consistent with all experimental bounds. There are many additional signatures of topcolor with large tu mixing, such as top(s)+jet(s) events, in which a top and a jet reconstruct a resonance mass, which make these models easily testable at the LHC.

ChargedZ′to conciliate the apparent disagreement betweentt¯Tevatron forward-backward asymmetry and LHC charge asymmetry

“…Apart from our model, many other models of NP [32][33][34] predict a resonance in the tj= " tj system of t " tj final state. We analyze in Sec.…”

The forward-backward top asymmetry in a singlet extension of the MSSM

“…Models that incorporate scalars within a variety of representations of the SM gauge group have been extensively studied [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Most recently, Blum et al [23] have argued that only a color-singlet weak doublet with an electroweak-scale mass and a very non-generic flavor structure of Yukawa couplings can enhance the top forward-backward asymmetry while being consistent with the tt production cross section and invariant mass distribution.…”

Search for a Narrow ttbar Resonance in ppbar Collisions at \sqrt s = 1.96 TeV (Combined D0, CDF)

“…Many of these models predict significant enhancements of the tt production cross section, the single-top production cross section, or the same-sign top-quark pair-production cross section, none of which have been confirmed by experimental tests. One class of models [9,10] evades the experimental constraints described above and predicts a new, unexplored experimental signature that consists of the production of a heavy new particle M in association with a top quark (pp → Mt or Mt), which decays via M →tq or tq as shown in the righthand Feynman diagram of Fig. 1.…”