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تسجيل مستخدم جديدTop Decays with Flavor Changing Neutral Higgs Interactions at the LHC
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We investigate the prospects for discovering a top quark decaying into one light Higgs boson along with a charm quark in top quark pair production at the CERN Large Hadron Collider (LHC). A general two Higgs doublet model is adopted to study the signature of flavor changing neutral Higgs decay $t to cphi^0$, %or $bar{t} to bar{c}phi^0$ where $phi^0$ could be CP-even ($H^0$) or CP-odd ($A^0$). The dominant physics background is evaluated with realistic acceptance cuts as well as tagging and mistagging efficiencies. For a reasonably large top-charm-Higgs coupling ($lambda_{tc}/lambda_{t} agt 0.09$), the abundance of signal events and the %that our acceptance cuts reduction in physics background allow us to establish a $5sigma$ signal for $M_phi sim 125$ GeV at the LHC with a center of mass energy ($sqrt{s}$) of 8 TeV and an integrated luminosity of 20 fb$^{-1}$. The discovery potential will be greatly enhanced with the full energy of $sqrt{s} = 14$ TeV.
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We investigate the prospects of discovering the top quark decay into a charm quark and a Higgs boson ($t to c h^0$) in top quark pair production at the CERN Large Hadron Collider (LHC). A general two Higgs doublet model is adopted to study flavor cha
nging neutral Higgs (FCNH) interactions. We perform a parton level analysis as well as Monte Carlo simulations using textsc{Pythia}~8 and textsc{Delphes} to study the flavor changing top quark decay $t to c h^0$, followed by the Higgs decaying into $tau^+ tau^-$, with the other top quark decaying to a bottom quark ($b$) and two light jets ($tto bWto bjj$). To reduce the physics background to the Higgs signal, only the leptonic decays of tau leptons are used, $tau^+tau^- to e^pmmu^mp +slashed{E}_T$, where $slashed{E}_T$ represents the missing transverse energy from the neutrinos. In order to reconstruct the Higgs boson and top quark masses as well as to effectively remove the physics background, the collinear approximation for the highly boosted tau decays is employed. Our analysis suggests that a high energy LHC at $sqrt{s} = 27$ TeV will be able to discover this FCNH signal with an integrated luminosity $mathcal{L} = 3$ ab$^{-1}$ for a branching fraction ${cal B}(t to ch^0) agt 1.4 times 10^{-4}$ that corresponds to a FCNH coupling $|lambda_{tch}| agt 0.023$. This FCNH coupling is significantly below the current ATLAS combined upper limit of $|lambda_{tch}| = 0.064$.
We investigate the prospects for discovering a top quark decaying into one light Higgs boson ($h^0$) along with a charm quark ($c$) in top quark pair production at the CERN Large Hadron Collider (LHC) and future hadron colliers. A general two Higgs d
oublet model is adopted to study the signature of flavor changing neutral Higgs (FCNH) interactions with $t to c h^0$, followed by $h^0 to WW^* to ell^+ ell^- + otE_T$, where $h^0$ is the CP-even Higgs boson and $ otE_T$ stands for missing transverse energy from neutrinos. We study the discovery potential for this FCNH signal and physics background from dominant processes with realistic acceptance cuts as well as tagging and mistagging efficiencies. Promising results are found for the LHC running at 13 TeV and 14 TeV center-of-mass energy as well as future pp colliders at 27 TeV and 100 TeV.
A general two Higgs doublet model (2HDM) is adopted to study the signature of flavor changing neutral Higgs (FCNH) decay $phi^0 to tbar{c}+bar{t}c$, where $phi^0$ could be a CP-even scalar ($H^0$) or a CP-odd pseudoscalar ($A^0$). Measurement of the
light 125 GeV neutral Higgs boson ($h^0$) couplings at the Large Hadron Collider (LHC) favor the decoupling limit or the alignment limit of a 2HDM, in which gauge boson and diagonal fermion couplings of $h^0$ approach Standard Model values. In such limit, FCNH couplings of $h^0$ are naturally suppressed by a small mixing parameter $cos(beta-alpha)$, while the off-diagonal couplings of heavier neutral scalars $phi^0$ are sustained by $sin(beta-alpha) sim 1$. We study physics background from dominant processes with realistic acceptance cuts and tagging efficiencies. Promising results are found for the LHC running at 13 or 14 TeV collision energies.
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