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Measurement of the sigma^o Lifetime

Description: The Coulomb production of {Sigma}{sup 0} hyperons on uranium and nickel nuclei has been measured in a beam of {Lambda} hyperons at the CERN Proton Synchrotron. The results for the {Sigma}{sup 0} lifetime, {tau}{Sigma}{sup 0} = (0.58 {+-} 0.13) x 10{sup -19} sec, and for the {Sigma}{sup 0}-{Lambda} magnetic transition moment, |{mu}{Sigma}{sub {Lambda}}| = (1.82{sub -0.18}{sup +0.25}) nuclear magnetons, are in agreement with SU(3) predictions.
Date: March 1, 1972
Creator: Devlin, T.J.; U., /Rutgers; March, R.H.; Pondrom, L.G.; U., /Wisconsin; Overseth, O.E. et al.
Partner: UNT Libraries Government Documents Department

A proposal to study Lambda0 polarization in the inclusive reaction p + p --> Lambda0 + anything with a liquid hydrogen target

Description: It is proposed that the {Lambda}{sup 0} polarization recently observed in inclusive production of {Lambda}{sup 0} by 300 GeV protons on beryllium be studied with 400 GeV protons in liquid hydrogen. A range of scaling variables 0 {le} p{sub +} {le} 2.3 GeV/c and .1 {le} X {le} 1 will be covered with good statistics. A total run of 150 hours is requested.
Date: September 1, 1975
Creator: Bunce, G.; Pondrom, L.; March, R.; /Wisconsin U., Madison; Devlin, T.; Edwards, R. et al.
Partner: UNT Libraries Government Documents Department

Search for a neutral Higgs boson decaying to a W boson pair in p antip collisions at s**(1/2) = 1.96-TeV

Description: The authors present the results of a search for standard model Higgs boson production with decay to WW*, identified through the leptonic final states e{sup +}e{sup -} {bar {nu}}{nu}, e{sup {+-}}{mu}{sup {-+}} {bar {nu}}{nu} and {mu}{sup +} {mu}{sup -} {bar {nu}}{nu}. This search uses 360 pb{sup -1} of data collected from p{bar p} collisions at {radical}s = 1.96 TeV by the upgraded Collider Detector at Fermilab (CDF II). They observe no signal excess and set 95% confidence level upper limits on the production cross section times branching ratio for the Higgs boson to WW* or any new scalar particle with similar decay products. These upper limits range from 5.5 to 3.2 pb for Higgs boson masses between 120 and 200 GeV/c{sup 2}.
Date: May 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Partner: UNT Libraries Government Documents Department

Comparison of Air Fluorescence and Ionization Measurements of E.M. Shower Depth Profiles: Test of a UHECR Detector Technique

Description: Measurements are reported on the fluorescence of air as a function of depth in electromagnetic showers initiated by bunches of 28.5 GeV electrons. The light yield is compared with the expected and observed depth profiles of ionization in the showers. It validates the use of atmospheric fluorescence profiles in measuring ultra high energy cosmic rays.
Date: October 7, 2005
Creator: Belz, J.; Cao, Z.; Huentemeyer, P.; Jui, C.C.H.; Martens, K.; Matthews, J. et al.
Partner: UNT Libraries Government Documents Department

Testing the CDF distributed computing framework

Description: A major source of CPU power for CDF (Collider Detector at Fermilab) is the CAF (Central Analysis Farm) [1] at Fermilab. The CAF is a farm of computers running Linux with access to the CDF data handling system and databases to allow CDF collaborators to run batch analysis jobs. Beside providing CPU power it has a good monitoring tool. The CAF software is a wrapper around a batch system, either fbsng [3] or condor, to submit jobs in a uniform way. So the submission to the CAF clusters inside and outside Fermilab from many computers with kerberos authentification is possible. It is mainly used to access datasets which comprise a large amount of files and analyze the data. Up to now the DCache system has been used to access the files. In autumn 2004 some of the important datasets will only be readable with the help of the data handling system SAM (Sequential Access to data via Metadata) [2]. This will be done in order to switch to using only one data handling system at Fermilab and on the remote sites. SAM has been used in run II to store, manage, deliver and track the processing of all data. It is designed to copy data to remote sites with remote analysis in mind. To prove CAF and SAM could provide the required CPU power and Data Handling, stress tests of the combined system were carried out. A second goal of CDF is to distribute computing. In 2005 50% of the computing shall be located outside of Fermilab. For this purpose CDF will use the DCAF (Decentralized CDF Analysis Farms) in combination with SAM. To achieve user friendliness the SAM station environment has to be common to all stations and adaptations to the environment have to be made.
Date: December 1, 2004
Creator: Bartsch, Valeria; Baranovski, Andrew; Belforte, Stefano; Burgon-Lyon, Morag; Garzoglio, Gabriele; Herber, Randolph et al.
Partner: UNT Libraries Government Documents Department

Application of the SAMGrid test-harness for performance evaluation and tuning of a distributed cluster implementation of data handling services

Description: The SAMGrid team has recently refactored its test harness suite for greater flexibility and easier configuration. This makes possible more interesting applications of the test harness, for component tests, integration tests, and stress tests. This new implementation of the test harness is a Python framework which uses XML for configuration and small plug-in python modules for specific test purposes We report on the architecture of the test harness and its recent application to stress tests of a new analysis cluster at Fermilab, to explore the extremes of analysis use cases and the relevant parameters for tuning in the SAMGrid station services. One current testing application is running on a 128-CPU analysis cluster with access to 6 TB distributed cache and also to a 2 TB centralized cache, permitting studies of different cache strategies. We have also studied the service parameters which affect the performance of retrieving data from tape storage. The use cases studied vary from those which will require rapid file delivery with short processing time per file, to the opposite extreme of long processing time per file. These results are interesting for their implications with regard to Grid operations, and illustrate the type of monitoring and test facilities required to accomplish such performance tuning.
Date: December 1, 2004
Creator: Lyon, A.; Baranovski, A.; Garzoglio, G.; Loebel-Carpenter, L.; Herber, R.; Illingworth, R. et al.
Partner: UNT Libraries Government Documents Department

SAMGrid integration of SRMs

Description: SAMGrid is the shared data handling framework of the two large Fermilab Run II collider experiments: DZero and CDF. In production since 1999 at D0, and going into production at CDF, the SAMGrid framework has been adapted over time to accommodate a variety of storage solutions and configurations, as well as the differing data processing models of these two experiments. This has been very successful for both experiments. Backed by primary data repositories of approximately 1 PB in size for each experiment, the SAMGrid framework delivers over 100 TB/day to DZero and CDF analyses at Fermilab and around the world. Each of the storage systems used with SAMGrid, however, has distinct interfaces, protocols, and behaviors. This led to different levels of integration of the various storage devices into the framework, which complicated the exploitation of their functionality and limited in some cases SAMGrid expansion across the experiments Grid. In an effort to simplify the SAMGrid storage interfaces, SAMGrid is adopting the Storage Resource Manager (SRM) concept as the universal interface to all storage devices. This simplifies the SAMGrid framework, especially the implementation of storage device interactions. It prepares the SAMGrid framework for future storage solutions equipped with SRM interfaces, without the need for long and risky software integration projects. In principle, any storage device with an SRM interface can be used with the SAMGrid framework. The integration of SRMs is an important further step towards evolving the SAMGrid framework into a co-operating collection of distinct, modular grid-oriented services. This report outlines how the SRMs are being integrated into the existing SAMGrid framework without disturbing on-going operations.
Date: December 1, 2004
Creator: Kennedy, R. D.; Baranovski, A.; Garzoglio, G.; Illingworth, R.; Kreymer, A.; Kumar, A. et al.
Partner: UNT Libraries Government Documents Department

The SAMGrid database server component: its upgraded infrastructure and future development path

Description: The SAMGrid Database Server encapsulates several important services, such as accessing file metadata and replica catalog, keeping track of the processing information, as well as providing the runtime support for SAMGrid station services. Recent deployment of the SAMGrid system for CDF has resulted in unification of the database schema used by CDF and D0, and the complexity of changes required for the unified metadata catalog has warranted a complete redesign of the DB Server. We describe here the architecture and features of the new server. In particular, we discuss the new CORBA infrastructure that utilizes python wrapper classes around IDL structs and exceptions. Such infrastructure allows us to use the same code on both server and client sides, which in turn results in significantly improved code maintainability and easier development. We also discuss future integration of the new server with an SBIR II project which is directed toward allowing the DB Server to access distributed databases, implemented in different DB systems and possibly using different schema.
Date: December 1, 2004
Creator: Loebel-Carpenter, L.; White, S.; Baranovski, A.; Garzoglio, G.; Herber, R.; Illingworth, R. et al.
Partner: UNT Libraries Government Documents Department

The SAMGrid monitoring service and its integration with MonALISA

Description: The SAMGrid team is in the process of implementing a monitoring and information service, which fulfills several important roles in the operation of the SAMGrid system, and will replace the first generation of monitoring tools in the current deployments. The first generation tools are in general based on text log-files and represent solutions which are not scalable or maintainable. The roles of the monitoring and information service are: (1) providing diagnostics for troubleshooting the operation of SAMGrid services; (2) providing support for monitoring at the level of user jobs; (3) providing runtime support for local configuration and other information which currently must be stored centrally (thus moving the system toward greater autonomy for the SAMGrid station services, which include cache management and job management services); (4) providing intelligent collection of statistics in order to enable performance monitoring and tuning. The architecture of this service is quite flexible, permitting input from any instrumented SAMGrid application or service. It will allow multiple backend storage for archiving of (possibly) filtered monitoring events, as well as real time information displays and active notification service for alarm conditions. This service will be able to export, in a configurable manner, information to higher level Grid monitoring services, such as MonALISA. We describe our experience to date with using a prototype version together with MonALISA.
Date: December 1, 2004
Creator: Lyon, A.; Vokac, P.; Zimmler, M.; Baranovski, G.; Garzoglio, G.; Loebel-Carpenter, L. et al.
Partner: UNT Libraries Government Documents Department

The Effect of Host Galaxies on Type Ia Supernovae in the SDSS-II Supernova Survey

Description: We present an analysis of the host galaxy dependencies of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2 to 3{sigma}) that SNe Ia are {approx_equal} 0.1 magnitudes brighter in passive host galaxies, than in star-forming hosts, after the SN Ia light curves have been standardized using the light curve shape and color variations: This difference in brightness is present in both the SALT2 and MCLS2k2 light curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R{sub V} {approx_equal} 1, while SNe Ia in star-forming hosts require R{sub V} {approx} 2. The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of > 4{sigma}) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.
Date: May 1, 2010
Creator: Lampeitl, Hubert; /Portsmouth U., ICG; Smith, Mathew; /Cape Town U. /Portsmouth U., ICG; Nichol, Robert C.; /Portsmouth U., ICG et al.
Partner: UNT Libraries Government Documents Department

Techniques of the FLASH Thin Target Experiment

Description: The fluorescence yield in air is reported for wavelength and pressure ranges of interest to ultra-high energy cosmic ray detectors. A 28.5 GeV electron beam was used to excite the fluorescence. Central to the approach was the system calibration, using Rayleigh scattering of a nitrogen laser beam. In atmospheric pressure dry air, at 304 K the yield is 20.8 {+-} 1.6 photons per MeV.
Date: October 30, 2007
Creator: Abbasi, R.; Abu-Zayyad, T.; Belov, K.; Belz, J.; U., /Utah; Bergman, D.R. et al.
Partner: UNT Libraries Government Documents Department

Production of D*+ (2010) mesons by high-energy neutrinos from the Tevatron

Description: Charged vector D*{sup +}(2010) meson production is studied in a high energy neutrino bubble chamber experiment with mean neutrino energy of 141 GeV. The D*{sup +} are produced in (5.6 {+-} 1.8)% of the neutrino charged current interactions, indicating a steep increase of cross section with energy. The mean fractional hadronic energy of the D*{sup +} meson is 0.55 {+-} 0.06.
Date: August 1, 1997
Creator: Asratian, A. E.; Aderholz, M.; Ammosov, V. V.; Barth, M.; Bingham, H. H.; Brucker, E. B. et al.
Partner: UNT Libraries Government Documents Department

A Measurement of the holographic minimum observable beam branching ratio in the Fermilab 15-foot bubble chamber

Description: Holography has been used successfully in combination with conventional optics for the first time in a large cryogenic bubble chamber, the 15-Foot Bubble Chamber at Fermilab, during a physics run. The innovative system combined the reference beam with the object beam, illuminating a conical volume of {approx} 1.4 m{sup 3}. Bubble tracks from neutrino interactions with a width of {approx} 120 {micro}m have been recorded with good contrast. The ratio of intensities of the object light to the reference light striking the film is called the Beam Branching Ratio. We obtained in our experiment an exceedingly small minimum-observable ratio of (0.54 {+-} 0.21) x 10{sup -7}. The technology has the potential for a wide range of applications.
Date: January 1, 1997
Creator: Aderholz, M.; Aggarwal, M. M.; Akbari, H.; Allport, P. P.; Badyal, S. K.; Ballagh, H. C. et al.
Partner: UNT Libraries Government Documents Department

Simplified Models for LHC New Physics Searches

Description: This document proposes a collection of simplified models relevant to the design of new-physics searches at the LHC and the characterization of their results. Both ATLAS and CMS have already presented some results in terms of simplified models, and we encourage them to continue and expand this effort, which supplements both signature-based results and benchmark model interpretations. A simplified model is defined by an effective Lagrangian describing the interactions of a small number of new particles. Simplified models can equally well be described by a small number of masses and cross-sections. These parameters are directly related to collider physics observables, making simplified models a particularly effective framework for evaluating searches and a useful starting point for characterizing positive signals of new physics. This document serves as an official summary of the results from the 'Topologies for Early LHC Searches' workshop, held at SLAC in September of 2010, the purpose of which was to develop a set of representative models that can be used to cover all relevant phase space in experimental searches. Particular emphasis is placed on searches relevant for the first {approx} 50-500 pb{sup -1} of data and those motivated by supersymmetric models. This note largely summarizes material posted at http://lhcnewphysics.org/, which includes simplified model definitions, Monte Carlo material, and supporting contacts within the theory community. We also comment on future developments that may be useful as more data is gathered and analyzed by the experiments.
Date: June 1, 2012
Creator: Alves, Daniele; /SLAC; Arkani-Hamed, Nima; /Princeton, Inst. Advanced Study; Arora, Sanjay; /Rutgers U., Piscataway et al.
Partner: UNT Libraries Government Documents Department