Measurement of the Top Pair Production Cross section at ATLAS

We present the measurement of the production cross section for top quark pair ($t\bar{t}$) in pp collisions at $\sqrt{s}$ = 7 TeV using the data recorded with the ATLAS detector at the Large Hadron Collider (LHC). Events are selected in single lepton (electron or muon) and dilepton ($ee$, $\mu\mu$, $e\mu$) topologies with multi-jets, and large missing transverse energy (MET). The combined result from these measurements is $\sigma_{t\bar{t}}$ = $176 \pm 5 \mathrm{(stat.)} ^{+13}_{-10}\mathrm{(syst.)} \pm 7 \mathrm{(lumi.)} \mathrm{pb}$, which is in good agreement with the Standard Model prediction.Comment: 8 pages, 9 figures, Proceedings of the DPF-2011 Conference, Providence, RI, August 8-13, 201

Beyond the resource curse: minerals and global development

This repository item contains a single issue of Issues in Brief, a series of policy briefs that began publishing in 2008 by the Boston University Frederick S. Pardee Center for the Study of the Longer-Range Future.This policy brief discusses the concept of the “resource curse” and the often-assumed connection between a country’s significant mineral wealth and violence and corruption. The paper argues that developing countries with abundant mineral resources can have positive and equitable development programs by establishing long-range plans that address governance, economic and social policies, and ecological issues associated with mineral extraction, and establishing appropriate frameworks and infrastructure to carry out these plans

Probing the Epoch of Reionization with Low Frequency Arrays

The Epoch of Reionization (EoR) is the epoch in which hydrogen in the Universe reionize after the "Dark Ages". This is the second of two major phase transitions that hydrogen in the Universe underwent, the first phase being the recombination era in which hydrogen became neutral at redshift about 1100. The EoR, occurs around z of 10 and is probably caused by the first radiation emitting astrophysical sources, hence it is crucial to our understanding of when and how the Universe "decided" to start forming astrophysical objects and how that influenced subsequent structure formation in the Universe. As such, the EoR is related to many fundamental questions in cosmology, galaxy formation, quasars and very metal poor stars; all are foremost research issues in modern astrophysics. The redshifted 21 cm hyperfine line is widely considered as the most promising probe for studying the EoR in detail. In the near future a number of low frequency radio telescopes (LOFAR, MWA, GMRT and SKA) will be able to observe the 21 cm radiation arriving from the high redshift Universe. In this paper I present our current picture of the ionization process, review the 21 cm line physics and discuss the challenges that the current generation experiments are expected to face. Finally, I discuss the potential of SKA in exploring the EoR and the Universe's Dark Ages.Comment: 9 pages and 9 figures. To be published in SKADS Conference 2009 "Widefield Science and Technology for the SKA", eds. S.A. Torchinsky, A. van Ardenne, T. van den Brink-Havinga, A. van Es, A.J. Faulkne