Operation of the CDF silicon vertex detector with colliding beams at Fermilab

In this paper we briefly describe the main features of the CDF Silicon Vertex Detector (SVX) and discuss its performance during actual colliding beam operation at the Fermilab Tevatron. Details on S/N ratio, alignment, resolution, and efficiency are given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87708/2/1908_1.pd

The Charge Asymmetry in W-Boson Decays Produced in p-pbar Collisions at sqrt(s) = 1.8 TeV

The charge asymmetry has been measured using $19,039~W$ decays recorded by the CDF detector during the 1992-93 run of the Tevatron Collider. The asymmetry is sensitive to the ratio of $d$ and $u$ quark distributions to $x<0.01$ at $Q^2 \approx M_W^2$, where nonperturbative effects are minimal. It is found that of the two current sets of parton distributions, those of Martin, Roberts and Stirling (MRS) are favored over the sets most recently produced by the CTEQ collaboration. The $W$ asymmetry data provide a stronger constraints on $d/u$ ratio than the recent measurements of $F_2^{\mu n}/F_2^{\mu p}$ which are limited by uncertainties originating from deutron corrections.Comment: to be published in PR

The James Webb Space Telescope Mission: Optical Telescope Element Design, Development, and Performance

The James Webb Space Telescope (JWST) is a large, infrared space telescope that has recently started its science program which will enable breakthroughs in astrophysics and planetary science. Notably, JWST will provide the very first observations of the earliest luminous objects in the Universe and start a new era of exoplanet atmospheric characterization. This transformative science is enabled by a 6.6 m telescope that is passively cooled with a 5-layer sunshield. The primary mirror is comprised of 18 controllable, low areal density hexagonal segments, that were aligned and phased relative to each other in orbit using innovative image-based wavefront sensing and control algorithms. This revolutionary telescope took more than two decades to develop with a widely distributed team across engineering disciplines. We present an overview of the telescope requirements, architecture, development, superb on-orbit performance, and lessons learned. JWST successfully demonstrates a segmented aperture space telescope and establishes a path to building even larger space telescopes.Comment: accepted by PASP for JWST Overview Special Issue; 34 pages, 25 figure

Preference Attainment: Determinants of Bargaining Success in the Context of Climate Change Negotiations

The process of negotiating climate change, as any bargaining process according to realism as well as liberalism, can be viewed a power game between the parties involved. Whether states are concerned with absolute gains or care more about relative gains is still widely debated. Analyzing the negotiation outcome of Cancun empirically, I explore which variables actually determine bargaining success. Are external power sources such as economic strength key for countries to achieve their negotiation goals, or are internal power sources such as negotiation skills equally important? And to what extent does the choice of hard vs. soft bargaining strategies matter for accomplishing these goals? Moreover, I examine whether variables intrinsically tied to countries, such as vulnerability to climate change, have an effect on negotiation success. These questions are answered using a novel dataset on the current climate change negotiations for which data on success, positions, and strategies of participating parties were collected. The results indicate that external power (measured by total GDP), extremity of positions, and vulnerability to climate change impacts are the most important determinants of success