Prospects for the Search for a Doubly-Charged Higgs in the Left-Right Symmetric Model with ATLAS

We estimate the potential for observation at the LHC of a doubly charged Higgs boson, as predicted in Left-Right symmetric models. Single production by vector boson fusion, $W^+W^+ \to \Delta_{L,R}^{++}$ and pair production by the Drell-Yan process $q \bar q \to \Delta_{L,R}^{++}\Delta_{L,R}^{--}$ are considered. Various decay channels are investigated: dileptons, including pairs of $\tau$'s, as well as $WW

Triangulating an exotic T quark

Limits on an exotic heavy quark $T$ are broadly generalized by considering the full range of $T\rightarrow Wb, th$ or $tZ$ branching ratios. We combine results of specific $T\rightarrow tZ$ and $T\rightarrow Wb$ searches with limits on various combinations of decay modes evaluated by re-interpreting other searches. We find strong bounds across the entire space of branching ratios, ranging from $m_T > 415$ GeV to $m_T > 557$ GeV at 95% confidence level

rho_T Production via W_L Z_L Fusion at Hadronic Colliders

Multiscale technicolor models predict the existence of high mass resonances at hadron colliders. Although the quark fusion process of production dominates, vector boson fusion offers the advantage of allowing forward jet tagging for background suppression. We calculate here the cross section and differential distributions for $\rho_T$ production in the vector boson fusion channel at the LHC.Comment: 9 pages, 6 figures, LaTe

Search for the radion using the ATLAS detector

The possibility of observing the radion using the ATLAS detector at LHC is investigated. Studies on searches for the Standard Model Higgs with the ATLAS detector are re-interpreted to obtain limits on radion decay to gamma-gamma and ZZ(*). The observability of radion decays into Higgs pairs, which subsequently decay into gamma-gamma+b-bbar or tau-tau+b-bbar is then estimate

BSM physics at the LHeC and the FCC-he

Electron-proton (e-p) colliders are an ideal laboratory to study common features of electron and quarks with production via electroweak bosons, leptoquarks, multi-jet final states and very forward physics, due to their impressive pseudorapidity coverage. In addition to these physics cases, there exist a broad Beyond the Standard Model (BSM) program aimed at exploring the capabilities of the LHeC [1] and FCC-he [2] for several New Physics scenarios. Although their centre-of-mass energy is down with respect to a pp collider by a factor of √Ep/Ee ∼ 10 (30) for the LHeC (FCC-he), they can be an invaluable tool to characterize BSM physics hints at ee and pp machines. The aim of this talk is to provide, on behalf of the BSM e-p Working Group, an overview of the aforementioned BSM program, by briefly summarizing the existing studies and reporting on the most recent progress. We expect that the ample scope in terms of NP models to be tested would enhance the synergies between the BSM and e-p communities

Dimensionless Coupling of Bulk Scalars at the LHC

We identify the lowest-dimension interaction which is possible between Standard Model brane fields and bulk scalars in 6 dimensions. The lowest-dimension interaction is unique and involves a trilinear coupling between the Standard Model Higgs and the bulk scalar. Because this interaction has a dimensionless coupling, it depends only logarithmically on ultraviolet mass scales and heavy physics need not decouple from it. We compute its influence on Higgs physics at ATLAS and identify how large a coupling can be detected at the LHC. Besides providing a potentially interesting signal in Higgs searches, such couplings provide a major observational constraint on 6D large-extra-dimensional models with scalars in the bulk.Comment: 20 page

New Fermions at e+^+e−^- Colliders: II.~Signals and Backgrounds

We discuss the production, at high--energy e$^+$e$^-$ linear colliders, of new heavy fermions predicted by extensions of the Standard Model. We analyze in great details the various signals and the corresponding backgrounds for both pair production and single production in association with ordinary fermions. Concentrating on new leptons, we use a model detector for e$^+$e$^-$ collisions at a center of mass energy of 500 GeV, to illustrate the discovery potential of the Next Linear Colliders.Comment: 22 pages + 9 figures (not included: available by mail from A. Djouadi), Preprint UdeM-LPN-TH-93-15

Prospects for the Search for a Standard Model Higgs Boson in ATLAS using Vector Boson Fusion

The potential for the discovery of a Standard Model Higgs boson in the mass range m_H < 2 m_Z in the vector boson fusion mode has been studied for the ATLAS experiment at the LHC. The characteristic signatures of additional jets in the forward regions of the detector and of low jet activity in the central region allow for an efficient background rejection. Analyses for the H -> WW and H -> tau tau decay modes have been performed using a realistic simulation of the expected detector performance. The results obtained demonstrate the large discovery potential in the H -> WW decay channel and the sensitivity to Higgs boson decays into tau-pairs in the low-mass region around 120 GeV.Comment: 20 pages, 13 ps figures, uses EPJ style fil