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

Search for Singly Charged Higgs in Vector Boson Scattering at the ep Colliders

We search for a five-plet singly charged Higgs $H_5^\pm$ in the Georgi-Machacek model at the ep colliders. The charged Higgs bosons are produced via the $ZW^{\pm}$ fusion process $p\, e^- \to j\, e^-\, H_5^\pm$, and decay as $H_5^\pm \to Z\, W^{\pm} \to (l^+ l^-)\, (jj)$. With a detector-level simulation at the FCC-eh and LHeC, a multi-variate analysis is performed to yield limits on the production cross section times branching ratio $\sigma (p\, e^- \to j e^- H_5^\pm) \times {\rm BR}(H_5^\pm \to Z\, W^\pm)$ and on the model parameter $\sin\theta_H$ for charged Higgs masses between 200 and 1000 GeV. The effects of electron beam polarization are also investigated.Comment: 7 pages, 6 figure

Strong WW scattering in unitary gauge

A method to embed models of strong $WW$ scattering in unitary gauge amplitudes is presented that eliminates the need for the effective $W$ approximation (EWA) in the computation of cross sections at high energy colliders.The cross sections obtained from the U-gauge amplitudes include the distributions of the final state fermions in $ff \rightarrow ffWW$, which cannot be obtained from the EWA. Since the U-gauge method preserves the interference of the signal and the gauge sector background amplitudes, which is neglected in the EWA, it is more accurate, especially if the latter is comparable to or bigger than the signal, as occurs for instance at small angles because of Coulomb singularities. The method is illustrated for on-shell $W^+W^+ \rightarrow W^+W^+$ scattering and for $qq \rightarrow qqW^+W^+$.Comment: 14 pages, Latex with 2 epsf-embedded postscript figure

Glucose metabolism in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a life-threatening interstitial lung disease of unknown aetiology characterized by progressive scarring of the lung parenchyma. Histologically, the hallmark of the disease is the presence of interspersed fibroblastic foci in the lung, composed of contractile myofibroblasts synthesizing a dense collagen-rich matrix. Transforming growth factor-β1 (TGFβ1) has been recognized as a key cytokine in the pathophysiology of IPF and other fibrotic disorders. Highly proliferative cells, such as cancer cells, reprogram their glucose metabolism through the activation of the PI3K-AKT-mTOR axis towards enhanced glycolysis, a process known as aerobic glycolysis. In view of the high biosynthetic nature of myofibroblasts, this thesis aimed to (1) describe the changes in glucose metabolism that occur during the process of TGFβ1-induced fibroblast to myofibroblast differentiation, (2) examine whether these changes are regulated by the PI3K-AKT-mTOR axis, and (3) examine the relationship between glucose uptake and fibrogenesis in an experimental model of lung fibrosis. For the in vitro experiments, the metabolic profile of primary human lung fibroblasts was assessed by examining cellular glucose uptake, glycolytic flux and mitochondrial respiration. Furthermore, using highly selective and potent pharmacological inhibitors, the role of the PI3K-AKT-mTOR pathway in promoting changes in glucose metabolism during fibroblast differentiation was examined. For the in vivo experiments, position emission tomography-computed tomography scanning and autoradiography were performed in the murine bleomycin model of lung injury and fibrosis following administration of radioactive 18F-labeled fluoro-2-deoxyglucose. Taken together, the data presented in this thesis demonstrate that the metabolic phenotype of fibroblasts changes during TGFβ1-induced fibroblast differentiation and is regulated by mTOR, in a PI3K-AKT-independent manner. This metabolic switch may further explain the observation of increased glucose uptake in the fibrotic lesions in the bleomycin model of lung fibrosis. These findings support the notion that pharmacological targeting of glucose metabolism and/or the mTOR kinase may be beneficial in preventing myofibroblast differentiation in IPF

Gauge invariant formulation of strong WW scattering

Models of strong $WW$ scattering in the $s$-wave can be represented in a gauge invariant fashion by defining an effective scalar propagator that represents the strong scattering dynamics. The \sigma(qq \ra qqWW) signal may then be computed in U-gauge from the complete set of tree amplitudes, just as in the standard model, without using the effective $W$ approximation (EWA). The U-gauge ``transcription'' has a wider domain of validity than the EWA, and it provides complete distributions for the final state quanta, including experimentally important jet distributions that cannot be obtained from the EWA. Starting from the usual formulation in terms of unphysical Goldstone boson scattering amplitudes, the U-gauge transcription is verified by using BRS invariance to construct the complete set of gauge and Goldstone boson amplitudes in $R_{\xi}$ gauge.Comment: single LaTeX file, no figures, 12 page

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