Stringent limits on top-quark compositeness from top anti-top production at the Tevatron and the LHC

Abstract

If the top quark is a composite state made out of some constituents, its interaction with the gluon will be modified. We introduce the leading effective operators that contribute to the radius and anomalous magnetic moment of the top quark and study their effect on the cross section for top anti-top production at the Tevatron and the LHC. Current measurements of the cross sections set a stringent limit on the scale of compositeness. This limit is comparable to similar limits obtained for light quarks and those from electroweak precision measurements. It can be used to constrain the parameter space of some composite Higgs models.

18 pages, 9 figures, 1 table. Analysis extended to quadratic contributions of the effective couplings. Study of top spin polarizations added. New confidence intervals obtained. Figures of the bounds replaced. Bounds on C2 result weaker. Version accepted for publication in PRD

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• Renormalization Group Constraints on New Top Interactions from Electroweak Precision Data
• Effective Field Theory in the top sector: do multijets help?
• Chromomagnetic and chromoelectric dipole moments of the top quark in the 4GTHDM
• Constraints on top quark non-standard interactions from Higgs and $t\bar{t}$ production cross sections
• Dipole-induced anomalous top quark couplings at the LHC
• Naturalness from a Composite Top?
• Top quark physics in the Large Hadron Collider era
• Limits on anomalous top quark gauge couplings from Tevatron and LHC data
• Probing top quark anomalous moments in $W$ boson associated single top quark production at the LHC using polarization and spin correlation