Karlsruhe Institute of Technology

About: Karlsruhe Institute of Technology is a education organization based out in Karlsruhe, Germany. It is known for research contribution in the topics: Computer science & Catalysis. The organization has 37946 authors who have published 82138 publications receiving 2197068 citations. The organization is also known as: KIT & University of Karlsruhe.

Updated Next-to-Next-to-Leading-Order QCD Predictions for the Weak Radiative B-Meson Decays.

Abstract: Weak radiative decays of the B mesons belong to the most important flavor changing processes that provide constraints on physics at the TeV scale. In the derivation of such constraints, accurate standard model predictions for the inclusive branching ratios play a crucial role. In the current Letter we present an update of these predictions, incorporating all our results for the O(α2s) and lower-order perturbative corrections that have been calculated after 2006. New estimates of nonperturbative effects are taken into account, too. For the CP- and isospin-averaged branching ratios, we find Bsγ=(3.36±0.23)×10−4 and Bdγ=(1.73+0.12−0.22)×10−5, for Eγ>1.6 GeV. Both results remain in agreement with the current experimental averages. Normalizing their sum to the inclusive semileptonic branching ratio, we obtain Rγ≡(Bsγ+Bdγ)/Bclν=(3.31±0.22)×10−3. A new bound from Bsγ on the charged Higgs boson mass in the two-Higgs-doublet-model II reads MH±>480 GeV at 95% C.L.

Non-Fermi-liquid behavior in a heavy-fermion alloy at a magnetic instability.

Abstract: The specific heat C and electrical resistivity \ensuremath{\rho} of the heavy-fermion alloy ${\mathrm{CeCu}}_{5.9}$${\mathrm{Au}}_{0.1}$ exhibit non-Fermi-liquid behavior well below 1 K, i.e., C/T\ensuremath{\propto}-ln(T/${\mathit{T}}_{0}$) and \ensuremath{\rho}=${\mathrm{\ensuremath{\rho}}}_{0}$+A'T, over more than a decade in temperature T. The magnetic susceptibility \ensuremath{\chi} measured in 0.1 T shows a cusp for T\ensuremath{\rightarrow}0. This behavior is attributed to the proximity to magnetic order: In contrast to ${\mathrm{CeCu}}_{6}$, ${\mathrm{CeCu}}_{6\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Au}}_{\mathit{x}}$ alloys show long-range antiferromagnetic order, with ${\mathit{T}}_{\mathit{N}}$\ensuremath{\rightarrow}0 for ${\mathit{x}}_{\mathit{c}}$=0.1. Hence ${\mathrm{CeCu}}_{5.9}$${\mathrm{Au}}_{0.1}$ is at the edge of a zero-temperature quantum phase transition. In a large magnetic field (B\ensuremath{\ge}3 T) Fermi-liquid behavior is recovered.

Multi-swarm Optimization in Dynamic Environments

Abstract: Many real-world problems are dynamic, requiring an optimization algorithm which is able to continuously track a changing optimum over time. In this paper, we present new variants of Particle Swarm Optimization (PSO) specifically designed to work well in dynamic environments. The main idea is to extend the single population PSO and Charged Particle Swarm Optimization (CPSO) methods by constructing interacting multi-swarms. In addition, a new algorithmic variant, which broadens the implicit atomic analogy of CPSO to a quantum model, is introduced. The multi-swarm algorithms are tested on a multi-modal dynamic function – the moving peaks benchmark – and results are compared to the single population approach of PSO and CPSO, and to results obtained by a state-of-the-art evolutionary algorithm, namely self-organizing scouts (SOS). We show that our multi-swarm optimizer significantly outperforms single population PSO on this problem, and that multi-quantum swarms are superior to multi-charged swarms and SOS.