I. Karliner

Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECams large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modeling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modeling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1 degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

Branching fractions of τ Leptons to three charged Hadrons

From electron-positron collision data collected with the CLEO detector operating at Cornell Electron Storage Ring near sqrt[s]=10.6 GeV, improved measurements of the branching fractions for tau decays into three explicitly identified hadrons and a neutrino are presented as B(tau(-)-->pi(-)pi(+)pi(-)nu(tau))=(9.13+/-0.05+/-0.46)%, B(tau(-)-->K-pi(+)pi(-)nu(tau))=(3.84+/-0.14+/-0.38) x 10(-3), B(tau(-)-->K-K+pi(-)nu(tau))=(1.55+/-0.06+/-0.09) x 10(-3), and B(tau(-)-->K-K+K-nu(tau))<3.7 x 10(-5) at 90% C.L., where the uncertainties are statistical and systematic, respectively.

Focal plane detectors for Dark Energy Camera (DECam)

The Dark Energy Camera is an wide field imager currently under construction for the Dark Energy Survey. This instrument will use fully depleted 250 μm thick CCD detectors selected for their higher quantum efficiency in the near infrared with respect to thinner devices. The detectors were developed by LBNL using high resistivity Si substrate. The full set of scientific detectors needed for DECam has now been fabricated, packaged and tested. We present here the results of the testing and characterization for these devices and compare these results with the technical requirements for the Dark Energy Survey.

CCD testing and characterization for Dark Energy Survey

A description of the plans and infrastructure developed for CCD testing and characterization for the DES focal plane detectors is presented. Examples of the results obtained are shown and discussed in the context of the device requirements for the survey instrument.

Search for neutrinoless τ decays involving the KS 0 meson

We have searched for lepton flavor violating decays of the tau lepton with one or two KS0 mesons in the final state. The data used in the search were collected with the CLEO II and II.V detectors at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 13.9 fb^-1 at the Upsilon(4S) resonance. No evidence for signals were found, therefore we have set 90% confidence level (C.L.) upper limits on the branching fractions B(tau -> e KS0) mu KS0) e 2KS0) mu 2KS0) < 3.4e-6. These represent significantly improved upper limits on the two-body decays and first upper limits on the three-body decays.

Measurement of D /emph> production in jets from p̅p collisions at √s =1.8 TeV

The production rate of charged {ital D}{sup *} mesons in jets has been measured in 1.8-TeV {ital {bar p}p} collisions at the Fermilab Tevatron with the Collider Detector at Fermilab. In a sample of approximately 32 300 jets with a mean transverse energy of 47 GeV obtained from an exposure of 21.1 nb{sup {minus}1}, a signal corresponding to 25.0{plus minus}7.5(stat){plus minus}2.0(syst) {ital D}{sup *{plus minus}}{r arrow}K{sup {minus plus}}{pi}{sup {plus minus}}{pi}{sup {plus minus}} events is seen above background. This corresponds to a ratio {ital N}({ital D}{sup *+}+D{sup *{minus}})/N(jet) =0.10{plus minus}0.03{plus minus}0.03 for {ital D}{sup *} mesons with fractional momentum {ital z} greater than 0.1.

The Readout and Control System of the Dark Energy Camera

The Dark Energy Camera (DECam) is a new 520 Mega Pixel CCD camera with a 3 square degree field of view designed for the Dark Energy Survey (DES). DES is a high precision, multi-bandpass, photometric survey of 5000 square degrees of the southern sky. DECam is currently being installed at the prime focus of the Blanco 4-m telescope at the Cerro- Tololo International Observatory (CTIO). In this paper we describe SISPI, the data acquisition and control system of the Dark Energy Camera. SISPI is implemented as a distributed multi-processor system with a software architecture based on the Client-Server and Publish-Subscribe design patterns. The underlying message passing protocol is based on PYRO, a powerful distributed object technology system written entirely in Python. A distributed shared variable system was added to support exchange of telemetry data and other information between different components of the system. We discuss the SISPI infrastructure software, the image pipeline, the observer console and user interface architecture, image quality monitoring, the instrument control system, and the observation strategy tool.

Automated characterization of CCD detectors for DECam

The Dark Energy Survey Camera (DECam) will be comprised of a mosaic of 74 charge-coupled devices (CCDs). The Dark Energy Survey (DES) science goals set stringent technical requirements for the CCDs. The CCDs are provided by LBNL with valuable cold probe data at 233 K, providing an indication of which CCDs are more likely to pass. After comprehensive testing at 173 K, about half of these qualify as science grade. Testing this large number of CCDs to determine which best meet the DES requirements is a very time-consuming task. We have developed a multistage testing program to automatically collect and analyze CCD test data. The test results are reviewed to select those CCDs that best meet the technical specifications for charge transfer efficiency, linearity, full well capacity, quantum efficiency, noise, dark current, cross talk, diffusion, and cosmetics.

The DECam Data Acquisition and Control System

In this paper we describe the data acquisition and control system of the Dark Energy Camera (DECam), which will be the primary instrument used in the Dark Energy Survey (DES). DES is a high precision multibandpath wide area survey of 5000 square degrees of the southern sky. DECam currently under construction at Fermilab will be a 3 square degree mosaic camera mounted at the prime focus of the Blanco 4m telescope at the Cerro-Tololo International Observatory (CTIO). The DECam data acquisition system (SISPI) is implemented as a distributed multi-processor system with a software architecture built on the Client-Server and Publish-Subscribe design patterns. The underlying message passing protocol is based on PYRO, a powerful distributed object technology system written entirely in Python. A distributed shared variable system was added to support exchange of telemetry data and other information between different components of the system. In this paper we discuss the SISPI infrastructure software, the image pipeline, the observer interface and quality monitoring system, and the instrument control system.

The read-out and control system of the DES camera (SISPI)

We describe the data acquisition and control system of the Dark Energy Camera (DECam), which will be the primary instrument used in the Dark Energy Survey (DES). DECam will be a 3 sq. deg. mosaic camera mounted at the prime focus of the Blanco 4m telescope at the Cerro-Tololo International Observatory (CTIO). The DECam data acquisition system (SISPI) is implemented as a distributed multi-processor system with a software architecture built on the Client-Server and Publish-Subscribe design patterns. The underlying message passing protocol is based on the SML inter-process communication software developed at CTIO [1]. For the DECam read-out and control system this software package was ported from LabVIEW to the Python and C programming languages. A shared variable system was added to support exchange of telemetry data and other information between different components of the system. In this paper we discuss the SISPI architecture, new concepts used in the design of the infrastructure software and provide an overview of the remaining components of the DES read-out and control system.