We study a possible explanation of a 3.0 $sigma$ excess recently reported by the ATLAS Collaboration in events with Z-peaked same-flavour opposite-sign lepton pair, jets and large missing transverse momentum in the context of gauge-mediated SUSY brea
king with more than one hidden sector, the so-called goldstini scenario. In a certain parameter space, the gluino two-body decay chain $tilde gto gtildechi^0_{1,2}to gZtilde G$ becomes dominant, where $tildechi^0_{1,2}$ and $tilde G$ are the Higgsino-like neutralino and the massive pseudo-goldstino, respectively, and gluino pair production can contribute to the signal. We find that a mass spectrum such as $m_{tilde g}sim 1000$ GeV, $m_{tildechi^0_{1,2}}sim 800$ GeV and $m_{tilde G}sim 600$ GeV demonstrates the rate and the distributions of the excess, without conflicting with the stringent constraints from jets plus missing energy analyses and with the CMS constraint on the identical final state.
We present the Higgs Characterisation (HC) framework to study the properties of the Higgs boson observed at 125 GeV. In this report, we focus on CP properties of the top-quark Yukawa interaction, and show predictions at next-to-leading order accuracy
in QCD, including parton-shower effects, for Higgs production in association with a single top quark at the LHC.
We present a detailed study of Higgs boson production in association with a single top quark at the LHC, at next-to-leading order accuracy in QCD. We consider total and differential cross sections, at the parton level as well as by matching short dis
tance events to parton showers, for both t-channel and s-channel production. We provide predictions relevant for the LHC at 13 TeV together with a thorough evaluation of the residual uncertainties coming from scale variation, parton distributions, strong coupling constant and heavy quark masses. In addition, for t-channel production, we compare results as obtained in the 4-flavour and 5-flavour schemes, pinning down the most relevant differences between them. Finally, we study the sensitivity to a non-standard-model relative phase between the Higgs couplings to the top quark and to the weak bosons.
We present search results based on next-to-leading order predictions for the pair production of color-adjoint leptons at the LHC. Quantum effects are sizable, dominated by pure QCD corrections, and sensitive to threshold effects. We illustrate the st
abilization of scale dependences and confirm an excellent agreement between fixed-order and multi-jet predictions for representative distributions. Finally, we examine the trademark collider signatures of leptogluon pairs. Based on the CMS leptoquark search we derive a mass bound of 1.2-1.3 TeV for charged leptogluons, significantly improving the constraints available in the literature.
We present completely general next-to-leading order predictions for squark and gluino production at the LHC, based on the fully automated MadGolem tool. Without any assumptions on the mass spectrum we predict production rates and examine the structur
e of the massless and massive quantum corrections. This allows us to quantify theory uncertainties induced by the spectrum assumptions commonly made. Going beyond total rates we compare general fixed-order distributions to resummed predictions from jet merging. As part of this comprehensive study we present the MadGolem treatment of ultraviolet, infrared and on-shell divergences.
We study the angular distribution of the charged lepton in the top-quark decay into a bottom quark and a W boson which subsequently decays into ell u_{ell}, when a hard gluon is radiated off. The absorptive part of the t to bWg decay amplitudes, whic
h gives rise to T-odd asymmetries in the distribution, is calculated at the one-loop level in perturbative QCD. The asymmetries at a few percent level are predicted, which may be observable at future colliders.
We explore how the polarization of the tau leptons in the cascade decay $tilde{q}to qtildechi^0_2to qtautildetauto qtautautildechi^0_1$ can be exploited to study mixing properties of neutralinos and staus. We present details of the analysis including
experimental effects such as transverse momentum cuts for the $tautopi u$ decay mode, and show that the di-pion invariant mass distribution provides valuable information on their properties.
