Detection of heavy charged Higgs bosons at future Linear Colliders

Abstract

Heavy charged Higgs bosons (H ± ) of a Type II 2-Higgs Doublet Model (2HDM) can be detected at future electron-positron Linear Colliders (LCs) even when their mass is larger than half the collider energy. The single Higgs mode e + e − → tbH − + c.c. → 4b + jj + ℓ + p miss T (where j represents a jet and with ℓ = e, µ) contributes to extend the discovery reach of H ± states into the mass region M H ± > ∼ √ s/2, where the well studied pair production channel e + e − → H − H + is no longer available. With a technique that allows one to reconstruct the neutrino four-momentum in the decay t → bW + → bℓ + ν, one can suppress the initially overwhelming main irreducible background due to e + e − → ttbb (via a gluon splitting into bb pairs) to a negligible level. However, for currently foreseen luminosities, one can establish a statistically significant H ± signal only over a rather limited mass region, of 20 GeV or so, beyond M H ± ≈ √ s/2, for very large or very small values of tan β and provided high b-tagging efficiency can be achieved.

Charged Higgs boson detection in theτνdecay mode at future linear colliders

“…A previous study reported in Refs. [27,28] charged Higgs decays to a pair. Let us call that ''Analysis A.''…”

“…The other search channels do not provide comparable results to those of Refs. [27,28] or to the results of this study.…”

“…Concluding the above summary of previous results, the most competitive search channel to the study presented in this work is the one studied in Refs. [27,28], whose results are compared in detail with those of this study in a separate section. The other search channels do not provide comparable results to those of Refs.…”

“…However, results from Refs. [27,28] show that including off-shell effects, the 5 contour would be extended by only about 10 GeV compared to the case of on-shell charged Higgs pair production. The e e H AE process was also studied in Ref.…”

“…It is reasonable to use the charged Higgs decay to top quarks when a heavy-charged Higgs is being analyzed, and that is, in fact, what was done in Refs. [27,28]. The charged Higgs branching ratio of decay to top quarks starts to be dominant when the charged Higgs mass goes beyond that of the top quark, allowing the charged Higgs boson to decay to a real on-shell top quark.…”