The increase in luminosity and center of mass energy at the FCC-hh will open up new clean channels where BSM contributions are enhanced at high energy. In this paper we study one such channel, $Wh \to \ellνγγ$. We estimate the sensitivity to the $\mathcal{O}_{φq}^{(3)}$, $\mathcal{O}_{φ{W}}$, and $\mathcal{O}_{φ\widetilde {W}}$ SMEFT operators. We find that this channel will be competitive with fully leptonic $WZ$ production in setting bounds on $\mathcal{O}_{φq}^{(3)}$. We also find that the double differential distribution in the $p_T^h$ and the leptonic azimuthal angle can be exploited to enhance the sensitivity to $\mathcal{O}_{φ\widetilde {W}}$. However, the bounds on $\mathcal{O}_{φ{W}}$ and $\mathcal{O}_{φ\widetilde {W}}$ we obtain in our analysis, though complementary and more direct, are not competitive with those coming from other measurements such as EDMs and inclusive Higgs measurements.
The future 100 TeV FCC-hh hadron collider will give access to rare but clean final states which are out of reach of the HL-LHC. One such process is the $Zh$ production channel in the $(ν\barν / \ell^{+}\ell^{-})γγ$ final states. We study the sensitivity of this channel to the $\mathcal{O}_{φq}^{(1)}$, $\mathcal{O}_{φq}^{(3)}$, $\mathcal{O}_{φu}$, and $\mathcal{O}_{φd}$ SMEFT operators, which parametrize deviations of the $W$ and $Z$ couplings to quarks, or, equivalently, anomalous trilinear gauge couplings (aTGC). While our analysis shows that good sensitivity is only achievable for $\mathcal{…
We study the CP-conserving and CP-violating dimension-six operators of Higgs-gauge boson couplings via $pp\toγγ$+n-jet signal process in a strongly interacting light Higgs based effective field theory framework at the center of mass energy of 100 TeV. In order to perform a simulation which includes realistic detector effects, the signal events in the existence of $\bar{c}_γ $, $\tilde{c}_γ$, $\bar{c}_{g} $ and $\tilde{c}_{g}$ Wilson coefficients and the relevant SM background events are generated in MadGraph, then passed through Pythia 8 for parton showering and finally run Delphes with FCC-hh…
Precision measurements of the Drell-Yan (DY) cross section at the LHC constrain new physics scenarios that involve new states with electroweak (EW) charges. We analyze these constraints and apply them to models that can address the LHC diphoton excess at 750 GeV. We confront these findings with LEP EW precision tests and show that DY provides stronger constraints than the LEP data. While 8 TeV data can already probe some parts of the interesting region of parameter space, LHC14 results are expected to cover a substantial part of the relevant terrain. We derive the bounds from the existing data…
An optimal-observable analysis of the lepton angular and energy distributions from top-quark pair production with semi-leptonic decays in e+e- collisions is used to predict the potential sensitivity of the FCC-ee to the couplings of the top quark to the photon and the Z.
We investigate the potential of the 100 TeV future circular collider (FCC-hh) to probe heavy neutrinos. We concentrate in particular on heavy neutrino production via a $U(1)_{B-L}$ $Z'$ gauge boson and contrast the resulting limits with that mediated by Standard Model weak currents. We consider heavy neutrino decays to semi-leptonic as well as fully leptonic final states, particularly with muon flavour, and we show the importance of considering searches both in prompt and displaced decays of the heavy neutrinos. For prompt final states, semi-leptonic modes are more promising due to smaller bac…
We study the anomalous $W^+W^-γ$ couplings in performing the production of the W-pair through the process $e^- p\,\rightarrow\,e^-γ^*γ^* p\,\rightarrow\,e^-W^+W^-p$ at the Large Hadron electron Collider (LHeC) and the Future Circular Collider-hadron electron (FCC-he). We examine the pure hadronic, the semi-leptonic and the pure leptonic decay channels of the produced W-pair. We assume the center-of-mass energies of $\sqrt{s}=1.30$ and $1.98$ TeV and the integrated luminosities of 10-100 fb$^{-1}$ for the LHeC and the center-of-mass energies of $\sqrt{s}=3.46$ and $5.29$ TeV and the integrated …
High precision experimental measurements of the properties of the Higgs boson at $\sim$ 125 GeV as well as electroweak precision observables such as the W -boson mass or the effective weak leptonic mixing angle are expected at future $e^+e^-$ colliders such as the FCC-ee. This high anticipated precision has to be matched with theory predictions for the measured quantities at the same level of accuracy. We briefly summarize the status of these predictions within the Standard Model (SM) and of the tools that are used for their determination. We outline how the theory predictions will have to be …
In this paper, we present detailed studies on the feasibility at $pp$, $e^-p$ and $e^+e^-$ colliders for model-independent sensitivity estimates on the total cross-section and on the anomalous $τ^+τ^-γ$ interaction through the tau pair production channels $pp \to pτ\bar τγp$, $e^-p \to e^- τ\bar τγp$ and $e^+e^- \to e^+ τ\bar τγe^-$ at the $γ^*γ^* \to τ^+τ^-γ$ mode. Measurements of the anomalous couplings of the $τ$-lepton $\tilde{a}_τ$ and $\tilde{d}_τ$ provide an excellent opportunity to probing extensions of the Standard Model. We estimate the sensitivity at the $95\%$ Confidence Level, and…
We study the diphoton excess at 750 GeV reported by ATLAS and CMS, by assuming that it corresponds to a new spin-two resonant state. We model this state as a massive graviton in a two-site model. We show that the very stringent bounds from $VV$ final states can be evaded naturally by considering that the Higgs is a pseudo Nambu-Goldstone boson. In this case the couplings of the graviton to the longitudinal electroweak gauge bosons can be parametrically suppressed. On the other hand, partial compositeness allows to suppress the leptonic channels. We compute loop-induced contributions to the gra…
In this paper, we consider the electroweak production cross-section of a single anti-top-quark, a neutrino and a photon via charged current through the $e^-p \to e^-\bar b \to \bar t ν_e γ\to \bar t(\to W^- \to (qq', l^- \barν_l)+b) ν_eγ$ signal. Further, we derived the sensitivity expected to the magnetic dipole moment $(\hat a_V)$ and the electric dipole moment $(\hat a_A)$ of the top-quark at the Future Circular Collider Hadron Electron (FCC-he). We present our study for $\sqrt{s}=7.07, 10\hspace{0.8mm}TeV$, ${\cal L}=50, 100, 300, 500, 1000\hspace{0.8mm}fb^{-1}$, $δ_{sys}=0, 3, 5\hspace{0.…
Precision study of electroweak symmetry breaking strongly motivates the construction of a lepton collider with center-of-mass energy of at least 240 GeV. Besides Higgsstrahlung ($e^+e^- \to hZ$), such a collider would measure weak boson pair production ($e^+e^- \to WW$) with an astonishing precision. The weak-boson-fusion production process ($e^+e^- \to ν\barν h$) provides an increasingly powerful handle at higher center-of-mass energies. High energies also benefit the associated top-Higgs production ($e^+e^-\to t\bar th$) that is crucial to constrain directly the top Yukawa coupling. The impa…
In the littlest Higgs model with T-parity(LHT), we study the single production of vector-like top partner with the subsequent decay $T_{+}\to Wb$ in the leptonic channel at the $ep$ colliders. Focus on the LHeC ($ \sqrt{s} $ = 1.98 TeV) and FCC-eh ($ \sqrt{s} $ = 5.29 TeV), we investigate the observability of the single top partner production with the unpolarized and polarized electron beams, respectively. As a result, the statistical significance can be enhanced by the polarized electron beams. Under the current constraints, the search for $T_{+}$ in the $Wb$ channel at the LHeC cannot provid…
We study the anomalous FCNC $tqγ$ and $tqg$ couplings via $pp\to Wbγ+X$ signal process including realistic detector effects for both leptonic and hadronic decay channels of the W boson at 100 TeV FCC-hh. The relevant background are considered in the cut based analysis to obtain not only limits on the anomalous $λ$ and $ζ$ couplings but also branching ratios of $t\to qγ$ and $t\to qg$ decay channels. We find that the sensitivity to the branching ratio of $t \to q γ$ channel is three order better than the available LHC experimental limits, and it is comparable for the branching ratio of the $t\t…
In this study, we investigate the process $pp \rightarrow W^{\pm} γ$ for the physics potential of the FCC-hh with $\sqrt{s}=100$ TeV to examine the anomalous $WWγ$ couplings defined by three CP-conserving and two CP-violating effective operators of dimension-6. The analysis containing the realistic detector effects is carried out in the mode where $W^{\pm}$ bosons in the final state decay into the leptonic channel. The best sensitivities obtained from the process $pp \rightarrow W^{\pm} γ$ on the anomalous couplings $C_{WWW}/ Λ^{2}$ and $C_{W,B}/ Λ^{2}$ determined by CP-conserving effective La…
We carry out a study in the approach of a dimension-8 effective field theory on the anomalous quartic $WWγγ$ couplings that arise from the process $pp \to Wγγ$ at the Future Circular Collider-hadron hadron (FCC-hh). The process is sensitive to the $WWγγ$ vertex, and future projections on the anomalous $f_ {M,i}/Λ^4$ and $ f_ {T,j}/Λ^4$ couplings can be put by measurements of $Wγγ$ production. We illustrate the physics opportunities and reach of the FCC-hh operating for a high integrated luminosity scenario of ${\cal L}=1, 5, 10, 30$ ${\rm ab}^{-1}$ of proton-proton collisions at a center-of-ma…
We examine the potential of the process $ep \rightarrow eγ^{*} γ^{*} p\rightarrow eτ\barτp$ at the Large Hadron Electron Collider (LHeC) and the Future Circular Hadron Electron Collider (FCC-he) to examine non-standard $τ\barτγ$ coupling in a model independent way by means of the effective Lagrangian approach. We perform pure leptonic and semileptonic decays for $τ^{-}τ^{+}$ production in the final state. Furthermore, we use $L = 10, 50, 100, 300, 500, 1000$ fb$^{-1}$ with at $\sqrt{s}=1.30, 1.98, 7.07, 10$ TeV and we consider systematic uncertainties of $δ_{sys}=0,5,10 \%$. The best sensitivi…
