Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “CDF”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30

When LEP and Tevatron combined with WMAP and XENON100 shed light on the nature of dark matter

Recently, several astrophysical data or would-be signals has been observed in different dark-matter oriented experiments. In each case, one could fit the data at the price of specific nature of the coupling between the Standard Model (SM) particles and a light Dark Matter candidate: hadrophobic (INTEGRAL, PAMELA) or leptophobic (WMAP Haze, dijet anomalies of CDF, FERMI Galactic Center observation). In this work, we show that when one takes into account the more recent LEP and Tevatron analysis, a light thermal fermionic Dark Matter (∼<10 GeV) that couples to electrons is mainly ruled out if one combines the analysis with WMAP constraints. We also study the special case of scalar dark matter, using a single-photon events simulation to constrain the coupling of dark matter to electron.

79 ASTRONOMY AND ASTROPHYSICS↗

Confronting new NICER mass-radius measurements with phase transition in dense matter and twin compact stars

The (re)analysis of data on the X-ray emitting pulsars PSR J0030+0451 and J0740+6620, as well as new results on PSR J0437-4715 and J1231-1411, are confronted with the predictions of the equation of state (EoS) models allowing for strong first-order phase transition for the mass-radius (M-R) diagram. Here, we use models that are based on a covariant density functional (CDF) EoS for nucleonic matter at low densities and a quark matter EoS, parameterized by the speed of sound, at higher densities. To account for the variations in the ellipses for PSR J0030+0451 obtained from different analyses, we examined three scenarios to assess their consistency with our models, focusing particularly on the potential formation of twin stars. We found that in two scenarios, where the ellipses for PSR J0030+0451 and J0437-4715 with masses close to the canonical mass ∼ 1.4 M ⊙ are significantly separated, our models allow for the presence of twin stars as a natural explanation for potential differences in the radii of these stars.

X-ray binaries↗

The message logging system for NOvA experiment

The message logging system provides the infrastructure for all of the distributed processes in the data acquisition (DAQ) to report status messages of various severities in a consistent manner to a central location, as well as providing the tools for displaying and archiving the messages. The message logging system has been developed over a decade, and has been run successfully on CDF and CMS experiments. The most recent work to the message logging system is to build it as a stand-alone package with the name MessageFacility which works for any generic framework or applications, with NO A as the first driving user. System designs and architectures, as well as the efforts of making it a generic library will be discussed. We also present new features that have been added.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

First ADS analysis of $B^- -> D^0K^-$ decays in hadron collisions

The CDF experiment reports the first measurement of branching fractions and CP-violating asymmetries of doubly-Cabibbo suppressed B(-') -> D(0)K(-') decays in hadron collisions, using the approach proposed by Atwood, Dunietz and Soni (ADS) to determine the CKM angle l. Using 5.0 fb(-')(1) of data the combined significance of both B(-') -> D(0)I K signals exceeds 5 sigma. First results in hadron collisions, obtained on 1.0 fb(-')(1) of data using the method of Gronau, London and Wyler (GLW) for the Cabibbo suppressed modes are also reported. Both ADS and GLW parameters are determined with accuracy comparable with B factories measurements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Measurements of top-quark properties at the Tevatron

Recent measurements of top-quark properties at the Tevatron are presented. CDF uses data corresponding up to 9.0 fb-1 to measure the ratio R of the branching fractions , the branching fraction for top-quarks decaying into τ leptons and the cross section for the production of an additional γ in t production. The results from all these measurements agree well with their respective Standard Model expectation. DØ uses 5.3 fb-1 of data to measure the t cross section as a function of the time. A time dependency would imply Lorentz invariance violation as implemented by the Standard Model extension. No time dependency is observed and DØ sets first limits in the top-quark sector for Lorentz invariance violation. DØ also determines indirectly the top quark width using the results of earlier measurements at DØ. The measured top quark width is in agreement with the SM expectation and does not show any hints for new physics contributions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Many-core applications to online track reconstruction in HEP experiments

Interest in parallel architectures applied to real time selections is growing in High Energy Physics (HEP) experiments. In this paper we describe performance measurements of Graphic Processing Units (GPUs) and Intel Many Integrated Core architecture (MIC) when applied to a typical HEP online task: the selection of events based on the trajectories of charged particles. We use as benchmark a scaled-up version of the algorithm used at CDF experiment at Tevatron for online track reconstruction – the SVT algorithm – as a realistic test-case for low-latency trigger systems using new computing architectures for LHC experiment. We examine the complexity/performance trade-off in porting existing serial algorithms to many-core devices. Measurements of both data processing and data transfer latency are shown, considering different I/O strategies to/from the parallel devices.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

A Data Handling System for Modern and Future Fermilab Experiments

Current and future Fermilab experiments such as Minerva, NOνA, and MicroBoone are now using an improved version of the Fermilab SAM data handling system. SAM was originally used by the CDF and D0 experiments for Run II of the Fermilab Tevatron to provide file metadata and location cataloguing, uploading of new files to tape storage, dataset management, file transfers between global processing sites, and processing history tracking. However SAM was heavily tailored to the Run II environment and required complex and hard to deploy client software, which made it hard to adapt to new experiments. The Fermilab Computing Sector has progressively updated SAM to use modern, standardized, technologies in order to more easily deploy it for current and upcoming Fermilab experiments, and to support the data preservation efforts of the Run II experiments.

Illingworth, R. A.↗

Top Quark Studies at D0

Years after its discovery in 1995 by CDF and D0, the top quark still undergoes intense investigations at the Tevatron. Using up to the full Run II data sample, new measurements of top quark production and properties by the D0 Collaboration are presented. In particular, the first observation of single top quark s-channel production, the measurement of differential tbar t distributions, forward-backward tbar t asymmetry, a new measurement of the top quark mass, and a measurement of the top quark charge are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Data preservation at the Fermilab Tevatron

The Fermilab Tevatron collider's data-taking run ended in September 2011, yielding a dataset with rich scientific potential. The CDF and DO experiments each have nearly 9 PB of collider and simulated data stored on tape. A large computing infrastructure consisting of tape storage, disk cache, and distributed grid computing for physics analysis with the Tevatron data is present at Fermilab. The Fermilab Run II data preservation project intends to keep this analysis capability sustained through the year 2020 or beyond. To achieve this, we are implementing a system that utilizes virtualization, automated validation, and migration to new standards in both software and data storage technology as well as leveraging resources available from currently-running experiments at Fermilab. Furthermore, these efforts will provide useful lessons in ensuring long-term data access for numerous experiments throughout high-energy physics, and provide a roadmap for high-quality scientific output for years to come.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

The OSG open facility: A sharing ecosystem

The Open Science Grid (OSG) ties together individual experiments’ computing power, connecting their resources to create a large, robust computing grid, this computing infrastructure started primarily as a collection of sites associated with large HEP experiments such as ATLAS, CDF, CMS, and DZero. In the years since, the OSG has broadened its focus to also address the needs of other US researchers and increased delivery of Distributed High Through-put Computing (DHTC) to users from a wide variety of disciplines via the OSG Open Facility. Presently, the Open Facility delivers about 100 million computing wall hours per year to researchers who are not already associated with the owners of the computing sites, this is primarily accomplished by harvesting and organizing the temporarily unused capacity (i.e. opportunistic cycles) from the sites in the OSG. Using these methods, OSG resource providers and scientists share computing hours with researchers in many other fields to enable their science, striving to make sure that these computing power used with maximal efficiency. Furthermore, we believe that expanded access to DHTC is an essential tool for scientific innovation and work continues in expanding this service.

97 MATHEMATICS AND COMPUTING↗

A review of event processing frameworks used in HEP

Today there are many different experimental event processing frameworks in use by running or about to be running experiments. This talk will discuss the different components of these frameworks. In the past there have been attempts at shared framework projects for example the collaborations on the BaBar framework (between BaBar, CDF, and CLEO), on the Gaudi framework (between LHCb and ATLAS), on AliROOT/FairROOT (between Alice and GSI/Fair), and in some ways on art (Fermilab based experiments) and CMS’ framework. However, for reasons that will be discussed, these collaborations did not result in common frameworks shared among the intended experiments. Though importantly, two of the resulting projects have succeeded in providing frameworks that are shared among many customer experiments: Fermilab's art framework and GSI/Fair's FairROOT. Interestingly, several projects are considering remerging their frameworks after many years apart. I'll report on an investigation and analysis of these realities. In addition, with the advent of the need for multi-threaded frameworks and the scarce available manpower, it is important to collaborate in the future, however it is also important to understand why previous attempts at multi-experiment frameworks either worked or didn't work.

99 GENERAL AND MISCELLANEOUS↗

Scidac-Data: Enabling Data Driven Modeling of Exascale Computing

Here, the SciDAC-Data project is a DOE-funded initiative to analyze and exploit two decades of information and analytics that have been collected by the Fermilab data center on the organization, movement, and consumption of high energy physics (HEP) data. The project analyzes the analysis patterns and data organization that have been used by NOvA, MicroBooNE, MINERvA, CDF, D0, and other experiments to develop realistic models of HEP analysis workflows and data processing. The SciDAC-Data project aims to provide both realistic input vectors and corresponding output data that can be used to optimize and validate simulations of HEP analysis. These simulations are designed to address questions of data handling, cache optimization, and workflow structures that are the prerequisites for modern HEP analysis chains to be mapped and optimized to run on the next generation of leadership-class exascale computing facilities. We present the use of a subset of the SciDAC-Data distributions, acquired from analysis of approximately 71,000 HEP workflows run on the Fermilab data center and corresponding to over 9 million individual analysis jobs, as the input to detailed queuing simulations that model the expected data consumption and caching behaviors of the work running in high performance computing (HPC) and high throughput computing (HTC) environments. In particular we describe how the Sequential Access via Metadata (SAM) data-handling system in combination with the dCache/Enstore-based data archive facilities has been used to develop radically different models for analyzing the HEP data. We also show how the simulations may be used to assess the impact of design choices in archive facilities.

97 MATHEMATICS AND COMPUTING↗

The OSG Open Facility: an on-ramp for opportunistic scientific computing

The Open Science Grid (OSG) is a large, robust computing grid that started primarily as a collection of sites associated with large HEP experiments such as ATLAS, CDF, CMS, and DZero, but has evolved in recent years to a much larger user and resource platform. In addition to meeting the US LHC community’s computational needs, the OSG continues to be one of the largest providers of distributed high-throughput computing (DHTC) to researchers from a wide variety of disciplines via the OSG Open Facility. The Open Facility consists of OSG resources that are available opportunistically to users other than resource owners and their collaborators. In the past two years, the Open Facility has doubled its annual throughput to over 200 million wall hours. More than half of these resources are used by over 100 individual researchers from over 60 institutions in fields such as biology, medicine, math, economics, and many others. Over 10% of these individual users utilized in excess of 1 million computational hours each in the past year. The largest source of these cycles is temporary unused capacity at institutions affiliated with US LHC computational sites. An increasing fraction, however, comes from university HPC clusters and large national infrastructure supercomputers offering unused capacity. Such expansions have allowed the OSG to provide ample computational resources to both individual researchers and small groups as well as sizable international science collaborations such as LIGO, AMS, IceCube, and sPHENIX. Opening up access to the Fermilab FabrIc for Frontier Experiments (FIFE) project has also allowed experiments such as mu2e and NOvA to make substantial use of Open Facility resources, the former with over 40 million wall hours in a year. We present how this expansion was accomplished as well as future plans for keeping the OSG Open Facility at the forefront of enabling scientific research by way of DHTC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Tevatron Beam Halo Collimation System: Design, Operational Experience and New Methods

Collimation of proton and antiproton beams in the Tevatron collider is required to protect CDF and D0 detectors and minimize their background rates, to keep irradiation of superconducting magnets under control, to maintain long-term operational reliability, and to reduce the impact of beam-induced radiation on the environment. In this article we briefly describe the design, practical implementation and performance of the collider collimation system, methods to control transverse and longitudinal beam halo and two novel collimation techniques tested in the Tevatron.

43 PARTICLE ACCELERATORS↗

HEAVILY OBSCURED ACTIVE GALACTIC NUCLEI IN HIGH-REDSHIFT LUMINOUS INFRARED GALAXIES

We take advantage of the rich multiwavelength data available in the Chandra Deep Field South (CDF-S), including the 4 Ms Chandra observations (the deepest X-ray data to date), in order to search for heavily obscured low-luminosity active galactic nuclei (AGNs) among infrared-luminous galaxies. In particular, we obtained a stacked rest-frame X-ray spectrum for samples of galaxies binned in terms of their IR luminosity or stellar mass. We detect a significant signal at E {approx} 1-8 keV, which we interpret as originating from a combination of emission associated with star formation processes at low energies combined with a heavily obscured AGN at E > 5 keV. We further find that the relative strength of this AGN signal decays with decreasing IR luminosity, indicating a higher AGN fraction for more luminous IR sources. Together, these results strongly suggest the presence of a large number of obscured AGNs in IR-luminous galaxies. Using samples binned in terms of stellar mass in the host galaxy, we find a significant excess at E = 6-7 keV for sources with M > 10{sup 11} M {sub sun}, consistent with a large obscured AGN population in high mass galaxies. In contrast, no strong evidence of AGN activity was found for less-massive galaxies. The integrated intensity at high energies indicates that a significant fraction of the total black hole growth, {approx}22%, occurs in heavily obscured systems that are not individually detected in even the deepest X-ray observations. There are also indications that the number of low-luminosity, heavily obscured AGNs does not evolve significantly with redshift, in contrast to the strong evolution seen in higher luminosity sources.

79 ASTRONOMY AND ASTROPHYSICS↗

DISCOVERY OF STRONG IRON K{alpha} EMITTING COMPTON THICK QUASARS AT z = 2.5 AND 2.9

We report the detection of the 6.4 keV iron K{alpha} emission line in two infrared-luminous, massive, star-forming BzK galaxies at z = 2.578 and z = 2.90 in the CDF-S. The Chandra 4 Ms spectra of BzK 4892 and BzK 8608 show a reflection-dominated continuum with strong iron lines, with rest-frame equivalent widths EW {approx} 2.3 keV and 1.2 keV, respectively, demonstrating Compton thick (CT) obscuration of the central active galactic nucleus (AGN). For BzK 8608, the line identification closely matches the existing photometric redshift derived from the stellar emission. We use the observed luminosities of the iron K{alpha} line, of the rest-frame mid-IR continuum and of the UV rest-frame narrow emission lines to infer intrinsic L{sub 2-10}{sub keV} {approx}> 10{sup 44} erg s{sup -1}, about 1.0-2.5 dex larger than the observed ones, hence confirming the presence of an absorber with N{sub H}>10{sup 24} cm{sup -2}. The two BzK galaxies have stellar masses of 5 x 10{sup 10} M{sub sun} and, based on Very Large Array 1.4 GHz and submillimeter 870 {mu}m observations, they appear to host vigorous starburst activity with star formation rate {approx} 300-700 M{sub sun} yr{sup -1} that is also optically thick. We estimate that the AGN might also conceivably account for an important fraction of the bolometric far-IR emission of the galaxies. The implied volume density of CT AGN with L{sub 2-10}{sub keV}>10{sup 44} erg s{sup -1} is in agreement with predictions from X-ray background synthesis models. These sources provide one of the first clear-cut observations of the long-sought phase of simultaneous, heavily obscured quasar and star formation activity, predicted by models of massive galaxy evolution at high redshifts.

79 ASTRONOMY AND ASTROPHYSICS↗

Cosmological cross-correlations and nearest neighbour distributions

ABSTRACT Cross-correlations between data sets are used in many different contexts in cosmological analyses. Recently, k-nearest neighbour cumulative distribution functions (kNN-CDF) were shown to be sensitive probes of cosmological (auto) clustering. In this paper, we extend the framework of NN measurements to describe joint distributions of, and correlations between, two data sets. We describe the measurement of joint kNN-CDFs, and show that these measurements are sensitive to all possible connected N-point functions that can be defined in terms of the two data sets. We describe how the cross-correlations can be isolated by combining measurements of the joint kNN-CDFs and those measured from individual data sets. We demonstrate the application of these measurements in the context of Gaussian density fields, as well as for fully non-linear cosmological data sets. Using a Fisher analysis, we show that measurements of the halo-matter cross-correlations, as measured through NN measurements are more sensitive to the underlying cosmological parameters, compared to traditional two-point cross-correlation measurements over the same range of scales. Finally, we demonstrate how the NN cross-correlations can robustly detect cross-correlations between sparse samples – the same regime where the two-point cross-correlation measurements are dominated by noise.

79 ASTRONOMY AND ASTROPHYSICS↗

Beyond the 3rd moment: a practical study of using lensing convergence CDFs for cosmology with DES Y3

ABSTRACT Widefield surveys probe clustered scalar fields – such as galaxy counts, lensing potential, etc. – which are sensitive to different cosmological and astrophysical processes. Constraining such processes depends on the statistics that summarize the field. We explore the cumulative distribution function (CDF) as a summary of the galaxy lensing convergence field. Using a suite of N-body light-cone simulations, we show the CDFs’ constraining power is modestly better than the second and third moments, as CDFs approximately capture information from all moments. We study the practical aspects of applying CDFs to data, using the Dark Energy Survey (DES Y3) data as an example, and compute the impact of different systematics on the CDFs. The contributions from the point spread function and reduced shear approximation are $\lesssim 1~{{\ \rm per\ cent}}$ of the total signal. Source clustering effects and baryon imprints contribute 1–10 per cent. Enforcing scale cuts to limit systematics-driven biases in parameter constraints degrade these constraints a noticeable amount, and this degradation is similar for the CDFs and the moments. We detect correlations between the observed convergence field and the shape noise field at 13σ. The non-Gaussian correlations in the noise field must be modelled accurately to use the CDFs, or other statistics sensitive to all moments, as a rigorous cosmology tool.

79 ASTRONOMY AND ASTROPHYSICS↗