Experimental systematic uncertainties (and object reconstruction) on top physics, their correlations, comparison ATLAS vs CMS (vs Tevatron) and common agreements

The experimental systematic uncertainties associated to the reconstruction and calibration of the objects appearing in top quark final states at the LHC and Tevatron are discussed. The strategies followed in the ATLAS and CMS experiments are compared in detail for the cases of the jet energy scale and $b$-tagging calibrations, where a categorisation of the associated uncertainty sources as well as the corresponding correlations across experiments has been proposed. The estimate of the non-prompt and fake lepton background to the top quark leptonic channels is also discussed.Comment: Proceedings of Top2014 International Workshop on Top-Quark Physic

The Disappearance of the HMS Umbra

A sailor aboard the HMS Umbra has a strange run-in with an ominous fog that won\u27t lift. As the days drag by, the weather is the least of his problems

Homological Domination in Large Random Simplicial Complexes

In this paper we state the homological domination principle for random multi-parameter simplicial complexes, claiming that the Betti number in one specific dimension (which is explicitly determined by the probability multi-parameter) significantly dominates the Betti numbers in all other dimensions. We also state and discuss evidence for two interesting conjectures which would imply a stronger version of the homological domination principle, namely that generically homology of a random simplicial complex coincides with that of a wedges of k-dimensional spheres. These two conjectures imply that under an additional assumption (specified in the paper) a random simplicial complex collapses to a k-dimensional complex homotopy equivalent to a wedge of spheres of dimension k.Comment: 8 pages, 1 figur

Beware of Courts Bearing Gifts: Transparency and the Court of Justice of the European Union

This article reconsiders the principle of transparency in the European Union (EU) legal order and takes as its focal point the contribution of the EU Courts as regards the presumptions of non-disclosure of EU documents. The aim is to investigate the role played by the judiciary in relation to a twofold question: How open can the Union’s decision-making be, and is it possible for citizens to participate in the decision-making process of EU institutions, bodies, offices and agencies? The article argues that accountability deficits in the field of access to documents have been filled, to an extent, by the EU Courts’ imposition of boundaries on the broad derogations to the right of access to documents. But nevertheless, the article concludes that the establishment through the case law of general presumptions against openness has fundamentally weakened the standards of accountability. Rather regrettably, although the EU legislature set the default position to the widest access to documents, this has been reversed to non-disclosure by the EU judiciary as regards non-legislative documents

One-loop calculations in Supersymmetric Lattice QCD

We study the self energies of all particles which appear in a lattice regularization of supersymmetric QCD (${\cal N}=1$). We compute, perturbatively to one-loop, the relevant two-point Green's functions using both the dimensional and the lattice regularizations. Our lattice formulation employs the Wilson fermion acrion for the gluino and quark fields. The gauge group that we consider is $SU(N_c)$ while the number of colors, $N_c$ and the number of flavors, $N_f$, are kept as generic parameters. We have also searched for relations among the propagators which are computed from our one-loop results. We have obtained analytic expressions for the renormalization functions of the quark field ($Z_\psi$), gluon field ($Z_u$), gluino field ($Z_\lambda$) and squark field ($Z_{A_\pm}$). We present here results from dimensional regularization, relegating to a forthcoming publication our results along with a more complete list of references. Part of the lattice study regards also the renormalization of quark bilinear operators which, unlike the non-supersymmetric case, exhibit a rich pattern of operator mixing at the quantum level.Comment: 6 pages, 5 figure, XII Quark Confinement proceeding