9,711 research outputs found
A CCD vertex deetctor for a high-energy linear e+e- collider
I present a summary of the experience with CCD-based vertex detectors at the
SLD experiment at SLAC, and discuss their advantages for use at a future
high-energy e+e- collider. The extensive R+D programme to improve further the
vertexing capabilities of CCD detectors is also outlined.Comment: 14 pages latex including 4 embedded ps files, to appear in
Proceedings Vertex99 Worksho
The Direct Detectability of Giant Exoplanets in the Optical
Motivated by the possibility that a coronagraph will be put on WFIRST/AFTA,
we explore the direct detectability of extrasolar giant planets (EGPs) in the
optical. We quantify a planet's detectability by the fraction of its orbit for
which it is in an observable configuration (). Using a suite of
Monte Carlo experiments, we study the dependence of upon the
inner working angle (IWA) and minimum achievable contrast () of
the direct-imaging observatory; the planet's phase function, geometric albedo,
single-scattering albedo, radius, and distance from Earth; and the semi-major
axis distribution of EGPs. We calculate phase functions for a given geometric
or single-scattering albedo, assuming various scattering mechanisms. We find
that the Lambertian phase function can predict significantly larger
's with respect to the more realistic Rayleigh phase function.
For observations made with WFIRST/AFTA's baseline capabilities
(, ), Jupiter-like planets
orbiting stars within 10, 30, and 50 parsecs of Earth have volume-averaged
observability fractions of 12%, 3%, and 0.5%, respectively. At 10
parsecs, such observations yield for low- to
modest-eccentricity planets with semi-major axes in the range
AU. If , this range extends to AU. We find
that, in all but the most optimistic configurations, the probability for
detection in a blind search is low (). However, with orbital
parameter constraints from long-term radial-velocity campaigns and Gaia
astrometry, the tools we develop in this work can be used to determine both the
most promising systems to target and when to observe them.Comment: 16 pages, 16 figures. Accepted for publication in Ap
Summary of Discussion Question 4: Energy Expandability of a Linear Collider
We report on Discussion Question 4, in Sub-group 1 (`TeV-class') of the
Snowmass Working Group E3: `Experimental Approaches: Linear Colliders', which
addresses the energy expandability of a linear collider. We first synthesize
discussions of the energy reach of the hardware of the 500 GeV designs for
TESLA and NLC/JLC. Next, we review plans for increasing the energy to 800-1000
GeV. We then look at options for expanding the energies to 1500 GeV and sketch
the two-beam accelerator approach to achieving multi-TeV energies.Comment: Presented at Snowmass 2001 (6 pages, 2 figures
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