Top production at the Tevatron/LHC and nonstandard, strongly interacting spin one particles

Abstract

In this Letter, we consider possible constraints from tt^- production on the gauge bosons of theories with an extended strong interaction sector such as axigluons or flavour universal colorons. Such constraints are found to be competitive with those obtained from the dijet data. The current tt^- data from the Tevatron rule out axigluon masses (m_A) up to 910 GeV and 920 GeV at 95% and 90% confidence levels, respectively. For the case of the flavour universal colorons, for cot ξ=1, where ξ is the mixing angle, the mass ranges m_C800 GeV and 895m_C1960 GeV are excluded at 95% confidence level (C.L.), whereas the same at 90% C.L. are m_C805 GeV and 880m_C2470 GeV. For cot ξ=2 on the other hand, the excluded range is m_C955(960) GeV and 1030m_C3250(1020m_C3250) GeV at 95% (90%) C.L., respectively. We point out that for higher axigluon/coloron masses, even for the dijet channel, the limits on the coloron mass, for cot ξ=1, may be different than those for the axigluon. We also compute the expected forward-backward asymmetry for the case of the axigluons which would allow it to be discriminated against the SM as also the colorons. We further find that at the LHC, the signal should be visible in the tt^- invariant mass spectrum for a wide range of axigluon and coloron masses that are still allowed. We point out how top polarisation may be used to further discriminate the axigluon and coloron case from the SM as well as from each other.