Top-quark couplings to TeV resonances at future lepton colliders

Abstract

We study the processes W L W L → tt and W L Z L → tb (tb) at future lepton colliders as probes of the couplings of the top quark to resonances at the TeV scale. We consider the cases in which the dominant low energy feature of a strongly interacting electroweak symmetry breaking sector is either a scalar or a vector resonance with mass near 1 TeV.We find that future lepton colliders with high energy and high luminosity have great potential to sensitively probe these physics scenarios. In particular, at a 1.5 TeV linear collider with an integrated luminosity of 200 fb −1 , we expect about 120 events for either a scalar or a vector to decay to tt, tb. Their leading partial decay widths, which characterize the coupling strengths, can be statistically determined to about 10% level.

Hadron collider signatures for new interactions of top and bottom quarks

“…Notice that the value g V ∼ 0.63 is about four times larger than the largest value we considered in Ref. [3]. In that case we were constrained by low energy bounds on V − W mixing, whereas…”

“…In order to parametrize new resonances that are heavy and narrow we argued in Ref. [3] that we had to consider models with more than one new resonance at a time. In this paper we adopt this scenario and do not require that our resonances be responsible for electroweak symmetry breaking.…”

Study ofVLVL→tt¯at the International Linear Collider includingO(<

“…[4,28,32]. Briefly, the relevant signal is a t t pair with missing transverse momentum carried by the neutrinos or from the beam electrons not observed by the detector.…”

“…Because the t-quark mass is the same order of magnitude as the scale of EWSB it has long been suspected that t-quark properties may provide hints about the nature of EWSB [23][24][25][26][27][28][29]. To this end studies have been performed of VV !…”

Top-BESS model and its phenomenology

“…The neutral component of the new vector triplet can also mimic couplings of a Z 0 spin-1 resonance [18,19] which has large couplings to the top and bottom quarks, vanishing couplings to W, Z, and very small couplings to fermions of the first two generations. The authors of [18,20,21] studied the effective description of the situation when the third quark generation couples extraordinarily to the new strong resonances, scalar and vector ones, under some simplifying assumptions. They also studied various processes as probes of the resonances.…”