2,449 research outputs found

    Searches for charged Higgs bosons in ATLAS

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    The presented analyses were performed by the Higgs to Complex States Working Group of the ATLAS Collaboration, using pp collisions data taken by the ATLAS detector in 2010 and 2011 at the LHC. An outline of the analysis and the result of the charged Higgs in the c¬Įs final state, which uses kinematic fitting algorithms, was presented. Upper limits on B(t ‚Üí bH+) √ó B(H+ ‚Üí c¬Įs) = 0.25 to 0.14 for mH¬Ī = 90 to 130 GeV have been derived. In the second part the charged Higgs in the hadronic ŌĄ final state analysis, which utilizes different techniques to estimate all background contributions from the data, was summarized. Values of the product of branching ratios B(t ‚Üí bH+)√óB(H+ ‚Üí ŌĄ + őĹ), larger than 0.03 to 0.10 have been excluded in the H ¬Ī mass range 90 to 160 GeV

    Structure-based optimization of potent, selective, and orally bioavailable CDK8 inhibitors discovered by high-throughput screening

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    The mediator complex-associated cyclin dependent kinase CDK8 regulates beta-catenin-dependent transcription following activation of WNT signaling. Multiple lines of evidence suggest CDK8 may act as an oncogene in the development of colorectal cancer. Here we describe the successful optimization of an imidazo-thiadiazole series of CDK8 inhibitors that was identified in a high-throughput screening campaign and further progressed by structure-based design. In several optimization cycles, we improved the microsomal stability, potency, and kinase selectivity. The initial imidazo-thiadiazole scaffold was replaced by a 3-methyl-1H-pyrazolo[3,4-b]-pyridine which resulted in compound 25 (MSC2530818) that displayed excellent kinase selectivity, biochemical and cellular potency, microsomal stability, and is orally bioavailable. Furthermore, we demonstrated modulation phospho-STAT1, a pharmacodynamic biomarker of CDK8 activity, and tumor growth inhibition in an APC mutant SW620 human colorectal carcinoma xenograft model after oral administration. Compound 25 demonstrated suitable potency and selectivity to progress into preclinical in vivo efficacy and safety studies

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s‚ąö=8 TeV with the ATLAS detector