113469755
Radiation Damage Study of the D0 Silicon Microstrip Tracker
The Run II DØ experiment at the Fermilab Tevatron collider ha s been operating since 2001. At the heart of the DØ tracking system is a silicon microstrip de tector. It is built from four layers of single sided and double sided sensors organized in six bar rels, and two sets of seven disks. An additional, very small radius layer of silicon sensors, c onsisting of eight barrels, was inserted during the spring of 2006. We monitor the silicon sensors for radiation damage. A bulk c arrier-type reversal was observed in the innermost layer of the original detector after 1.5 fb −1 of integrated luminosity. We present the results of aging studies and predictions for lifetime of the detector for the rest of Run II at the Tevatron.
125296528
Low-mass Higgs searches at the Tevatron
30114466
Amplitudes for Higgs bosons plus four partons
In this talk we consider amplitudes for processes involving a Higgs boson, either scalar or pseudoscalar, plus four light partons. These amplitudes are relevant to the production of a Higgs boson plus two jets in hadronic collisions. They are also relevant to calculating the transverse momentum spectrum for Higgs bosons at next-to-leading order in the strong coupling. We work in the limit that the top quark is much heavier than the Higgs bosons and use effective Lagrangians for the interactions of gluons with the Higgs bosons. We present the amplitudes involving a Higgs boson and: 1) four gluons, 2) two quarks and two gluons; and 3) four quarks. We show that the pseudoscalar amplitudes are nearly identical to those for the scalar case, the only differences being the overall size and the relative signs between terms.
121557595
Monitoring Sco X-1 for the detection of gravitational waves with networks of gravitational wave detectors
Searching for gravitational waves triggered by electromagnetic astronomical observations has several benefits: prior information about the source location enhances detection efficiency, and the use of time coincidence implies analysis of only a small stretch of data which allows sophisticated analysis with high computational costs. During postprocessing, knowledge about the source enables accurate reconstruction of the source parameters, leading to an astrophysical interpretation. In this paper, we present a triggered search pipeline called RIDGE and we demonstrate the search for gravitational waves from Sco X-1, in which X-ray bursts occur frequently, using simulated data. In the analysis, we consider the optimum network combination for Sco X-1.
119295671
The Blanco Cosmology Survey: Data Acquisition, Processing, Calibration, Quality Diagnostics and Data Release
The Blanco Cosmology Survey (BCS) is a 60 night imaging survey of ~80 deg2 of the southern sky located in two fields: (α, δ) = (5 hr, –55°) and (23 hr, –55°). The survey was carried out between 2005 and 2008 in griz bands with the Mosaic2 imager on the Blanco 4 m telescope. The primary aim of the BCS survey is to provide the data required to optically confirm and measure photometric redshifts for Sunyaev-Zel'dovich effect selected galaxy clusters from the South Pole Telescope and the Atacama Cosmology Telescope. We process and calibrate the BCS data, carrying out point-spread function-corrected model-fitting photometry for all detected objects. The median 10σ galaxy (point-source) depths over the survey in griz are approximately 23.3 (23.9), 23.4 (24.0), 23.0 (23.6), and 21.3 (22.1), respectively. The astrometric accuracy relative to the USNO-B survey is ~45 mas. We calibrate our absolute photometry using the stellar locus in grizJ bands, and thus our absolute photometric scale derives from the Two Micron All Sky Survey, which has ~2% accuracy. The scatter of stars about the stellar locus indicates a systematic floor in the relative stellar photometric scatter in griz that is ~1.9%, ~2.2%, ~2.7%, and ~2.7%, respectively. A simple cut in the AstrOmatic star-galaxy classifier spread_model produces a star sample with good spatial uniformity. We use the resulting photometric catalogs to calibrate photometric redshifts for the survey and demonstrate scatter δz/(1 + z) = 0.054 with an outlier fraction η < 5% to z ~ 1. We highlight some selected science results to date and provide a full description of the released data products.
26249886
SPT-CL J2040-4451: An SZ-Selected Galaxy Cluster at z = 1.478 With Significant Ongoing Star Formation
SPT-CL J2040–4451—spectroscopically confirmed at z = 1.478—is the highest-redshift galaxy cluster yet discovered via the Sunyaev-Zel'dovich effect. SPT-CL J2040–4451 was a candidate galaxy cluster identified in the first 720 deg^2 of the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey, and has been confirmed in follow-up imaging and spectroscopy. From multi-object spectroscopy with Magellan-I/Baade+IMACS we measure spectroscopic redshifts for 15 cluster member galaxies, all of which have strong [O II] λλ3727 emission. SPT-CL J2040–4451 has an SZ-measured mass of M_(500, SZ) = 3.2 ± 0.8 × 10^(14) M_☉ h^(-1)_(70), corresponding to M_(200, SZ) = 5.8 ± 1.4 × 10^(14) M_☉ h^(-1)_(70). The velocity dispersion measured entirely from blue star-forming members is σ_v = 1500 ± 520 km s^(–1). The prevalence of star-forming cluster members (galaxies with >1.5 M_☉ yr^(–1)) implies that this massive, high-redshift cluster is experiencing a phase of active star formation, and supports recent results showing a marked increase in star formation occurring in galaxy clusters at z ≳ 1.4. We also compute the probability of finding a cluster as rare as this in the SPT-SZ survey to be >99%, indicating that its discovery is not in tension with the concordance ΛCDM cosmological model.