Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Defending the open society: Foucault, Hayek, and the problem of biopolitical order

'Defending the Open Society: Foucault, Hayek and the Problem of BiopThe aim of this paper is to throw new light on a previously neglected aspect of Hayek's political theory. In order to show the significance of Hayek's evolutionary argument, the paper draws on Foucault's thesis about the relationship between political order, life and war. Focusing on Hayek's conception of the open society and, in particular, on the evolutionary ontology that grounds it, the paper shows how his liberalism reflects the problematic that Foucault began to elucidate in his 1976 lecture course Society must be defended. The paper concludes by showing how the biopolitical dimension of Hayek's liberalism might affect our understanding of his political project.olitical Order', Economy & Society, forthcoming 2013

Foucault and Hobbes on politics, security and war

This article engages and seeks to develop Michel Foucault’s account of the nexus between modern politics, security, and war. Focusing on his 1976 lecture series Society Must Be Defended, the article considers Foucault’s tentative hypothesis about how the logic of war becomes inscribed into modern politics through the principle of security. Contra Foucault, it is suggested that this nexus can already be found in the proto-liberal political philosophy of Thomas Hobbes. In order to make this argument, the article focuses on the ontological dimension of Hobbes' thought. It suggests that the relationship between the state of war and political order in Hobbes is more complex and more ambiguous than Foucault thought. Rather than being transcended, the Hobbesian state of war is appropriated by the state, and converted into the fundamental antagonism between reason and passion. The latter gives rise to a regime of security through which a relationship of war is inscribed into the Hobbesian commonwealth

Hobbes, war, movement

While informed by Foucault's understanding of power in terms of war and circulation, this article challenges Foucault's static reading of Hobbes. Contextualising Hobbes's political thought within the scientific ideas that he was inspired by, this article reveals that there is more to Hobbes than the static, depoliticising image of the contract. Hobbes's political thought is premised upon an ontology of movement; that is, his account of political order pivots on a double movement in which war constitutes the very possibility of social and political relations as well as of their continued reproduction via circulation. It is this conceptualisation of order that makes Hobbes's liberal political thought genealogically significant. And it is the model of a play of (re)productive movements—in certain respects close to Foucault's own conception of power—that can be used productively for thinking about governance and resistance today

Classical Liberalism, Non-interventionism and the Origins of European Integration: Luigi Einaudi, Friedrich A. von Hayek, Wilhelm Röpke

What did classical liberal thinkers contribute to the theoretical underpinnings of the European unification project? This paper examines works by Luigi Einaudi, Friedrich A. von Hayek and Wilhelm Röpke, attempting to understand to what extent the nineteenth-century pacifist tradition of classical liberalism came back to life in works of these authors. Their views on the international order show a certain degree of homogeneity—but up to a point. While Einaudi and Hayek were distinctively more favourable to the European project, Röpke had a less favourable view of European unificaton, fearing it may result in increasing centralisation. They, nonetheless, shared some common elements in understanding international order that we trace back to nineteenth-century liberalism.2reservedmixedMasala, Antonio; Mingardi, AlbertoMasala, Antonio; Mingardi, Albert

Search for direct top squark pair production in final states with two leptons in s=13\sqrt{s} = 13 TeV pppp collisions with the ATLAS detector

International audienceThe results of a search for direct pair production of top squarks in events with two opposite-charge leptons (electrons or muons) are reported, using $36.1~\hbox {fb}^{-1}$ of integrated luminosity from proton–proton collisions at $\sqrt{s}=13$ TeV collected by the ATLAS detector at the Large Hadron Collider. To cover a range of mass differences between the top squark $\tilde{t}$ and lighter supersymmetric particles, four possible decay modes of the top squark are targeted with dedicated selections: the decay $\tilde{t} \rightarrow b \tilde{\chi }_{1}^{\pm }$ into a b-quark and the lightest chargino with $\tilde{\chi }_{1}^{\pm } \rightarrow W \tilde{\chi }_{1}^{0}$ , the decay $\tilde{t} \rightarrow t \tilde{\chi }_{1}^{0}$ into an on-shell top quark and the lightest neutralino, the three-body decay $\tilde{t} \rightarrow b W \tilde{\chi }_{1}^{0}$ and the four-body decay $\tilde{t} \rightarrow b \ell \nu \tilde{\chi }_{1}^{0}$ . No significant excess of events is observed above the Standard Model background for any selection, and limits on top squarks are set as a function of the $\tilde{t}$ and $\tilde{\chi }_{1}^{0}$ masses. The results exclude at 95% confidence level $\tilde{t}$ masses up to about 720 GeV, extending the exclusion region of supersymmetric parameter space covered by previous searches

Searches for the ZγZ\gamma decay mode of the Higgs boson and for new high-mass resonances in pppp collisions at s=13\sqrt{s} = 13 TeV with the ATLAS detector

International audienceThis article presents searches for the Zγ decay of the Higgs boson and for narrow high-mass resonances decaying to Zγ, exploiting Z boson decays to pairs of electrons or muons. The data analysis uses 36.1 fb$^{−1}$ of pp collisions at $\sqrt{s}=13$ recorded by the ATLAS detector at the CERN Large Hadron Collider. The data are found to be consistent with the expected Standard Model background. The observed (expected — assuming Standard Model pp → H → Zγ production and decay) upper limit on the production cross section times the branching ratio for pp → H → Zγ is 6.6. (5.2) times the Standard Model prediction at the 95% confidence level for a Higgs boson mass of 125.09 GeV. In addition, upper limits are set on the production cross section times the branching ratio as a function of the mass of a narrow resonance between 250 GeV and 2.4 TeV, assuming spin-0 resonances produced via gluon-gluon fusion, and spin-2 resonances produced via gluon-gluon or quark-antiquark initial states. For high-mass spin-0 resonances, the observed (expected) limits vary between 88 fb (61 fb) and 2.8 fb (2.7 fb) for the mass range from 250 GeV to 2.4 TeV at the 95% confidence level