A boost for the EW SUSY hunt: monojet-like search for compressed sleptons at LHC14 with 100 fb^-1

Current Large Hadron Collider (LHC) analyses are blind to compressed supersymmetry (SUSY) models with sleptons near the lightest super partner (LSP) in mass: $m_{\tilde{l}} - m_{\tilde{\chi}_1^0} \equiv \Delta m \lesssim 60$ GeV. We present a search sensitive to the very compressed range $3~\text{GeV} < \Delta m < 24~\text{GeV}$ using the channel $p p \rightarrow \tilde{l}^+ \tilde{l}^- +\rm{jet} \rightarrow$ $l^+ l^- \tilde{\chi}_1^0 \tilde{\chi}_1^0 +\rm{jet}$ with soft same-flavor leptons and one hard jet from initial state radiation ($p_{\rm T}^j >100$ GeV). The sleptons recoil against the jet boosting them and their decay products, making the leptons detectable and providing substantial missing transverse momentum. We use the kinematic variable $m_{\rm T 2}$ along with a different-flavor control region to reduce the large standard model backgrounds and control systematic uncertainty. We find the analysis should allow LHC14 with $100~\text{fb}^{-1}$ to search for degenerate left-handed selectrons and smuons in the compressed region up to $m_{\tilde{l}_L} \lesssim 150$ GeV. In addition, it should be sensitive to $m_{\tilde{l}_L} \lesssim 110$ GeV for the very challenging case of auto-concealed SUSY, in which left-handed sleptons decay to the Kaluza-Klein tower of a modulino LSP which lives in $d=6$ extra dimensions. In both the compressed spectrum and auto-concealed SUSY scenarios this analysis will need more data to improve on LEP2 limits for right-handed sleptons due to their smaller cross sections.Comment: 15 pages, 3 figures, updated citations in v

Higgs boson search significance deformations due to mixed-in scalars

The existence of exotic scalars that mix with the Standard Model (SM) Higgs boson can affect Higgs boson phenomenology in a multitude of ways. We consider two light Higgs bosons with shared couplings to SM fields and with masses close to each other, in the range where the h \to WW \to l \nu l \nu is an important search channel. In this channel, we do not find the dilution of significance of the `SM-like' Higgs boson that is naively expected because of the mixing. This is because of leakage of events from the decay of the other scalar into its signal region. Nevertheless, we show that the broadening of the h\to WW \to l \nu l \nu significance plots of Standard Model Higgs boson searches could indicate the first evidence of the the extra scalar state.Comment: 6 pages, 6 figures; v2: all plots now made with the lighter Higgs mass equal to 125 GeV and other minor corrections made, to be published in Physics Letters

Resilience of Hierarchical Critical Infrastructure Networks

Concern over the resilience of critical infrastructure networks has increased dramatically over the last decade due to a number of well documented failures and the significant disruption associated with these. This has led to a large body of research that has adopted graph-theoretic based analysis in order to try and improve our understanding of infrastructure network resilience. Many studies have asserted that infrastructure networks possess a scale-free topology which is robust to random failures but sensitive to targeted attacks at highly connected hubs. However, many studies have ignored that many networks in addition to their topological connectivity may be organised either logically or spatially in a hierarchical system which may significantly change their response to perturbations. In this paper we explore if hierarchical network models exhibit significantly different higher-order topological characteristics compared to other network structures and how this impacts on their resilience to a number of different failure types. This is achieved by investigating a suite of synthetic networks as well as a suite of ‘real world’ spatial infrastructure networks

Neo-Hamiltonian Republicans and Military Reform in the Progressive Era: 1898-1912.

The Spanish-American War changed the course of American history. In a few months the United States acquired a colonial empire and adopted a policy of overseas involvement that greatly altered future world events. The political victory of a few military reformers and politicians, who endorsed Social Darwinism, over those who upheld the ideas of Jefferson and Jackson, destroyed the international isolation of the American republic. No matter what successive political administrations claimed, they inherited substantial overseas commitments. The group that engineered this profound change in American foreign and defence policy were led by Elihu Root, John Hay, Leonard Wood, Alfred Thayer Mahan and Theodore Roosevelt. These men were convinced that American economic prosperity and political independence depended upon exerting influence overseas. The creation of English-speaking democracies world-wide, which endorsed free trade, would guarantee American prosperity and peace. Josiah Strong\u27s evangelism, which claimed advanced nations had a duty to help the less fortunate, provided American imperialists with moral legitimacy. American expansion required both allies and an efficient military. During the late nineteenth century top-ranking British officials decided that Britain could not maintain its industrial and naval preeminence. An informal alliance between the United States and Great Britain became increasingly attractive to key decision-makers in both countries. This decision led to poorer relations with Germany and Japan because these states resented Anglo-American imperialism and its industrial power. The American army highlighted these changes. The Spanish-American War had displayed deficiencies of command, training, and equipment that proved unacceptable to politicians wishing to influence the world. Army reform provoked political debate. Supporters of local control, volunteerism, and the ideologies of Jefferson and Jackson opposed military reform. Led by William Jennings Bryan, they challenged the view that national efficiency required a professional civil service, army, and navy responsible to federal authority. Ideas from Germany, Britain, France, and Switzerland were used to construct the new army. American business organisation, partly responsible for unparalleled economic growth, influenced the rhetoric of reform and new command structure of the army. The reforms included a General Staff structure, War College, and closer national guard-regular army cooperation; creating the basis for today\u27s American army