Related papers: The process `e+ e- --> H t t-bar' and its backgrou…
The process e+e- -> Htt can be exploited at future Linear Colliders to measure the Higgs-top Yukawa coupling. In this note, we estimate the size of the irreducible backgrounds in the channel Htt -> bbbb WW -> bbbb ln qq, for the case of a…
Determination of the top-quark Yukawa couplings in the process e+ e- -> t \bar{t} Z has been studied for the high luminosity option (\int L=500\fbinver) of a linear e+e- collider. Polarization of the electron beam has been considered. The…
The cross section for the reaction $e^+e^- \to t\bar{t} H$ depends sensitively on the top quark Yukwawa coupling $\lambda_t$. We calculate the rate for $t\bar{t}H$ production, followed by the decay $H\to b\bar{b}$, for a Standard Model…
The strength of the Yukawa coupling of the leptons and quarks with the Higgs boson is uniquely determined by the Higgs mechanism for generating masses in the Standard Model. The top-Higgs coupling can be measured directly in the process…
The processes e+e- -> t tbar/b bbar + Higgs allow to measure the Yukawa couplings between Higgs bosons and heavy quarks in supersymmetric theories. The complete set of next-to-leading order SUSY-QCD corrections to the cross sections of…
The determination of the Yukawa coupling of the top quark to the Higgs boson is one of the most important measurements that a future e^+e^- linear collider could provide. For a Higgs boson of mass greater than 350 GeV, this coupling can be…
A feasibility study of the measurement of the top-Higgs Yukawa coupling at a future linear e+e- collider operating at sqrt(s)=800 GeV is presented. As compared to previous existing studies, much effort has been put in a ``realistic…
We investigate the possibility of probing an extra Higgs boson at future linear $e^+ e^-$ colliders. We consider the production process $e^+e^- \to H\nu \bar\nu$, followed by the decay $H \to W^+W^-$, where $H$ is the extra…
The complete matrix elements for $e^+e^-\to b\bar bW^\pm H^\mp$ and $e^+e^-\to b\bar bH^+H^-$ are computed at tree-level within the Minimal Supersymmetric Standard Model. Rates of interest to phenomenological analyses at the Next Linear…
We report on the feasibility of the direct measurement of the top Yukawa coupling g_t at the International Linear Collider (ILC) during its first phase of operation with a center-of-mass energy of 500 GeV. The signal and background models…
We investigate the inclusive production of a Higgs boson with a pair of heavy quarks (t-tbar b-bbar), in e^+e^- collisions at high energies, sqrt(s)=500 GeV and sqrt(s)=1 TeV. We consider both the Standard Model and the supersymmetric case.…
We estimate the sensitivity to the top-quark Yukawa coupling $y_t$ at future $e^+e^-$ colliders. We go beyond the standard approach that focuses on $t\bar t h$ production and consider final states with a Higgs boson but not top quarks. The…
The Future Circular Collider (FCC-ee) offers the unique opportunity of studying the Higgs coupling to the electron, $y_e$, via resonant s-channel production, $e^+e^- \to H$, in a dedicated run at $\sqrt{s} = m_H$. The signature for direct…
We discuss associated production of a Higgs boson with a pair of $t {\bar t}$ quarks at a future high energy $e^+e^-$ collider. The process $e^+e^-\to t {\bar t}h$ is particularly sensitive to the presence of new physics and we consider the…
Yukawa couplings between Higgs bosons and quarks in supersymmetric theories can be measured in the processes e^+e^- -> Q Qbar + Higgs. We have determined the cross sections of these processes in the minimal supersymmetric model including…
In the framework of the littlest Higgs($LH$) model, we consider the processes $e^{+}e^{-}\to\nu\bar{\nu}H^{0}$ and $e^{+}e^{-}\to W^{*}W^{*}\nu\bar{\nu}\to\nu\bar{\nu}t\bar{t}$, and calculate the contributions of new particles to the cross…
We consider a general effective Lagrangian for couplings of a Higgs boson to the top-quark to dimension-six operators including CP violation effects. Constraints on some of them are derived from the $Z\to b\bar b$ data. We study the process…
The top quark Yukawa coupling to the intermediate mass Higgs boson can be determined in the reaction e+e- -> t anti-t H that, after taking into account decays, will be detected at the International Linear Collider through reactions with 8…
We show how a measurement of the process pp-->t tbar H + X at the LHC and a measurement of the Higgs boson branching ratios BR(H-->b bar) and BR(H-->W+W-) at a future linear electron positron collider can be combined to extract a…
We discuss the reaction of associated production of a top quark pair and a Higgs boson at the future e+e- linear collider that can be used to determine the top-Higgs Yukawa coupling. Taking into account decays of the top quarks and the…