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Measurement of the Top Quark Mass in the Lepton+Jets Channel Using the Lepton Transverse Momentum (open access)

Measurement of the Top Quark Mass in the Lepton+Jets Channel Using the Lepton Transverse Momentum

This letter reports a measurement of the top quark mass, M{sub top}, in data from p{bar p} collisions at {radical}s = 1.96 TeV corresponding to 2.7 fb{sup -1} of integrated luminosity at the Fermilab Tevatron using the CDF II detector. Events with the lepton+jets topology are selected. An unbinned likelihood is constructed based on the dependence of the lepton transverse momentum, P{sub T}, on M{sub top}. A maximum likelihood fit to the data yields a measured mass M{sub top} = 176.9 {+-} 8.0{sub stat} {+-} 2.7{sub syst} GeV/c{sup 2}. In this measurement, the contribution by the jet energy scale uncertainty to the systematic error is negligible. The result provides an important consistency test for other M{sub top} measurements where explicit use of the jet energy is made for deriving the top quark mass.
Date: January 1, 2011
Creator: Aaltonen, T.; Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Object Type: Article
System: The UNT Digital Library
Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production (open access)

Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production

We present a new measurement of the inclusive forward-backward t{bar t} production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of 5.3 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, recorded with the CDF II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the t{bar t} rest frame, and in both cases are found to be consistent with CP conservation under interchange of t and {bar t}. In the t{bar t} rest frame, the asymmetry is observed to increase with the t{bar t} rapidity difference, {Delta}y, and with the invariant mass M{sub t{bar t}} of the t{bar t} system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large {Delta}y and M{sub t{bar t}}. For M{sub t{bar t}} {ge} 450 GeV/c{sup 2}, the parton-level asymmetry in the t{bar t} rest frame is A{sup t{bar t}} = 0.475 {+-} 0.114 compared to a next-to-leading order QCD prediction of 0.088 {+-} 0.013.
Date: January 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Object Type: Article
System: The UNT Digital Library
Search for High Mass Resonances Decaying to Muon Pairs in $\sqrt{s}=1.96$ TeV $p\bar{p}$ Collisions (open access)

Search for High Mass Resonances Decaying to Muon Pairs in $\sqrt{s}=1.96$ TeV $p\bar{p}$ Collisions

We present a search for a new narrow, spin-1, high mass resonance decaying to {mu}{sup +}{mu}{sup -} + X, using a matrix element based likelihood and a simultaneous measurement of the resonance mass and production rate. In data with 4.6 fb{sup -1} of integrated luminosity collected by the CDF detector in p{bar p} collisions at {radical}s = 1960 GeV, the most likely signal cross section is consistent with zero at 16% confidence level. We therefore do not observe evidence for a high mass resonance, and place limits on models predicting spin-1 resonances, including M > 1071 GeV/c{sup 2} at 95% confidence level for a Z{prime} boson with the same couplings to fermions as the Z boson.
Date: January 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the Forward-Backward Asymmetry in the $B \to K^{(*)} \mu^+ \mu^-$ Decay and First Observation of the $B^0_s \to \phi \mu^+ \mu^-$ Decay (open access)

Measurement of the Forward-Backward Asymmetry in the $B \to K^{(*)} \mu^+ \mu^-$ Decay and First Observation of the $B^0_s \to \phi \mu^+ \mu^-$ Decay

We reconstruct the rare decays B{sup +} {yields} K{sup +} {mu}{sup +}{mu}{sup -}, B{sup 0} {yields} K*(892){sup 0} {mu}{sup +}{mu}{sup -}, and B{sub s}{sup 0} {yields} {phi}(1020){mu}{sup +}{mu}{sup -} in a data sample corresponding to 4.4 fb{sup -1} collected in p{bar p} collisions at {radical}s = 1.96 TeV by the CDF II detector at the Fermilab Tevatron Collider. Using 120 {+-} 16 B{sup +} {yields} K{sup +} {mu}{sup +}{mu}{sup -} and 101 {+-} 12 B{sup 0} {yields} K*{sup 0} {mu}{sup +}{mu}{sup -} decays we report the branching ratios. In addition, we report the measurement of the differential branching ratio and the muon forward-backward asymmetry in the B{sup +} and B{sup 0} decay modes, and the K*{sup 0} longitudinal polarization in the B{sup 0} decay mode with respect to the squared dimuon mass. These are consistent with the theoretical prediction from the standard model, and most recent determinations from other experiments and of comparable accuracy. We also report the first observation of the B{sub s}{sup 0} {yields} {phi}{mu}{sup +}{mu}{sup -} decay and measure its branching ratio {Beta}(B{sub s}{sup 0} {yields} {phi}{mu}{sup +}{mu}{sup -}) = [1.44 {+-} 0.33 {+-} 0.46] x 10{sup -6} using 27 {+-} 6 signal events. This is currently …
Date: January 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Object Type: Article
System: The UNT Digital Library
Azimuthal decorrelations and multiple parton interactions in photon+2 jet and photon+3 jet events in ppbar collisions at sqrt{s}=1.96 TeV (open access)

Azimuthal decorrelations and multiple parton interactions in photon+2 jet and photon+3 jet events in ppbar collisions at sqrt{s}=1.96 TeV

Samples of inclusive {gamma} + 2 jet and {gamma} + 3 jet events collected by the D0 experiment with an integrated luminosity of about 1 fb{sup -1} in p{bar p} collisions at {radical}s = 1.96 TeV are used to measure cross sections as a function of the angle in the plane transverse to the beam direction between the transverse momentum (p{sub T}) of the {gamma} + leading jet system (jets are ordered in p{sub T}) and p{sub T} of the other jet for {gamma} + 2 jet, or p{sub T} sum of the two other jets for {gamma} + 3 jet events. The results are compared to different models of multiple parton interactions (MPI) in the pythia and sherpa Monte Carlo (MC) generators. The data indicate a contribution from events with double parton (DP) interactions and are well described by predictions provided by the pythia MPI models with p{sub T}-ordered showers and by sherpa with the default MPI model. The {gamma} + 2 jet data are also used to determine the fraction of events with DP interactions as a function of the azimuthal angle and as a function of the second jet p{sub T}.
Date: January 1, 2011
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Acharya, Bannanje Sripath; Inst., /Tata et al.
Object Type: Article
System: The UNT Digital Library
Search for W'->tb resonances with left- and right-handed couplings to fermions (open access)

Search for W'->tb resonances with left- and right-handed couplings to fermions

We present a search for the production of a heavy gauge boson, W{prime}, that decays to third-generation quarks, by the D0 Collaboration in p{bar p} collisions at {radical}s = 1.96 TeV. We set 95% confidence level upper limits on the production cross section times branching fraction. For the first time, we set limits for arbitrary combinations of left- and right-handed couplings of the W{prime} boson to fermions. For couplings with the same strength as the standard model W boson, we set the following limits for M(W{prime}) > m({nu}{sub R}): M(W{prime}) > 863 GeV for purely left-handed couplings, M(W{prime}) > 885 GeV for purely right-handed couplings, and M(W{prime}) > 916 GeV if both left- and right-handed couplings are present. The limit for right-handed couplings improves for M(W{prime}) < m({nu}{sub R}) to M(W{prime}) > 890 GeV.
Date: January 1, 2011
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Alexeev, Guennadi D. et al.
Object Type: Article
System: The UNT Digital Library
Impact of Large Scale Energy Efficiency Programs On Consumer Tariffs and Utility Finances in India (open access)

Impact of Large Scale Energy Efficiency Programs On Consumer Tariffs and Utility Finances in India

Large-scale EE programs would modestly increase tariffs but reduce consumers' electricity bills significantly. However, the primary benefit of EE programs is a significant reduction in power shortages, which might make these programs politically acceptable even if tariffs increase. To increase political support, utilities could pursue programs that would result in minimal tariff increases. This can be achieved in four ways: (a) focus only on low-cost programs (such as replacing electric water heaters with gas water heaters); (b) sell power conserved through the EE program to the market at a price higher than the cost of peak power purchase; (c) focus on programs where a partial utility subsidy of incremental capital cost might work and (d) increase the number of participant consumers by offering a basket of EE programs to fit all consumer subcategories and tariff tiers. Large scale EE programs can result in consistently negative cash flows and significantly erode the utility's overall profitability. In case the utility is facing shortages, the cash flow is very sensitive to the marginal tariff of the unmet demand. This will have an important bearing on the choice of EE programs in Indian states where low-paying rural and agricultural consumers form the majority of …
Date: January 20, 2011
Creator: Abhyankar, Nikit & Phadke, Amol
Object Type: Report
System: The UNT Digital Library
[Abilene City Council Minutes: 2011] (open access)

[Abilene City Council Minutes: 2011]

Ledger containing minutes of the City Council in Abilene, Texas documenting the group's discussions and activities from January 13, 2011 to December 15, 2011.
Date: 2011-01-13/2011-12-15
Creator: Abilene (Tex.)
Object Type: Book
System: The Portal to Texas History
The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays (open access)

The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays

Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.
Date: January 1, 2011
Creator: Abreu, P.; Aglietta, M.; Ahn, E. J.; Allard, D.; Allekotte, I.; Allen, J. et al.
Object Type: Article
System: The UNT Digital Library
Lebanon: Background and U.S. Relations (open access)

Lebanon: Background and U.S. Relations

This report provides an overview of Lebanese politics, recent events in Lebanon, and current issues in U.S.-Lebanon relations.
Date: January 19, 2011
Creator: Addis, Casey L.
Object Type: Report
System: The UNT Digital Library
U.S. Security Assistance to Lebanon (open access)

U.S. Security Assistance to Lebanon

This report discusses key issues facing U.S. policy makers and members of Congress when considering U.S. security assistance in the context of U.S. policy toward Lebanon. These key issues include assessing the effectiveness of U.S. assistance programs, assessing overall U.S. policy toward Lebanon, and managing relations with other external actors.
Date: January 19, 2011
Creator: Addis, Casey L.
Object Type: Report
System: The UNT Digital Library
Hezbollah: Background and Issues for Congress (open access)

Hezbollah: Background and Issues for Congress

Report that discusses Lebanon's Hezbollah, a Shiite Islamist militia, political party, social welfare organization, and U. S. State Department-designated terrorist organization. The report also discusses recent Hezbollah-related conflicts, Hezbollah's relationship with other Lebanese political parties, and U. S. policy regarding Hezbollah.
Date: January 3, 2011
Creator: Addis, Casey L. & Blanchard, Christopher M.
Object Type: Report
System: The UNT Digital Library
The Middle East: Selected Key Issues and Options for the 112th Congress (open access)

The Middle East: Selected Key Issues and Options for the 112th Congress

This report provides an overview of key issues, relating to the Middle East including the war in Afghanistan, terrorism, foreign assistance, democracy promotion, a summary of past congressional action on these issues, and options for congressional consideration during the 112th Congress.
Date: January 3, 2011
Creator: Addis, Casey L.; Blanchard, Christopher M.; Katzman, Kenneth; Sharp, Jeremy M. & Zanotti, Jim
Object Type: Report
System: The UNT Digital Library
Development of a Portable Muon Witness System (open access)

Development of a Portable Muon Witness System

Since understanding and quantifying cosmic ray induced radioactive backgrounds in copper and germanium are important to the MAJORANA DEMONSTRATOR, methods are needed for monitoring the levels of such backgrounds produced in materials being transported and processed for the experiment. This report focuses on work conducted at Pacific Northwest National Laboratory to develop a muon witness system as a one way of monitoring induced activities. The operational goal of this apparatus is to characterize cosmic ray exposure of materials. The cosmic ray flux at the Earth’s surface is composed of several types of particles, including neutrons, muons, gamma rays and protons. These particles induce nuclear reactions, generating isotopes that contribute to the radiological background. Underground, the main mechanism of activation is by muon produced spallation neutrons since the hadron component of cosmic rays is removed at depths greater than a few tens of meters. This is a sub-dominant contributor above ground, but muons become predominant in underground experiments. For low-background experiments cosmogenic production of certain isotopes, such as 68Ge and 60Co, must be accounted for in the background budgets. Muons act as minimum ionizing particles, depositing a fixed amount of energy per unit length in a material, and have a very …
Date: January 1, 2011
Creator: Aguayo Navarrete, Estanislao; Kouzes, Richard T. & Orrell, John L.
Object Type: Report
System: The UNT Digital Library
Fate and Effects of Barium and Radium-Rich Fluid Emissions of Hydrocarbon Seeps on the Benthic Habitats of the Gulf of Mexico Offshore Louisiana (open access)

Fate and Effects of Barium and Radium-Rich Fluid Emissions of Hydrocarbon Seeps on the Benthic Habitats of the Gulf of Mexico Offshore Louisiana

An analysis of how barium and radium-laced fluid seeps affect the climate and habitats of the Gulf of Mexico offshore Louisiana.
Date: January 2011
Creator: Aharon, Paul; Gent, Dan Van; Fu, Baoshun & Scott, L. Max
Object Type: Report
System: The UNT Digital Library
International Trade and Finance: Key Policy Issues for the 112th Congress (open access)

International Trade and Finance: Key Policy Issues for the 112th Congress

Report concerning a variety of issues faced by the 112th Congress. Topics include trade negotiations with South Korea, Panama, Colombia, and China, export controls and sanctions, and international financial institutions.
Date: January 21, 2011
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
International Trade and Finance: Key Policy Issues for the 112th Congress (open access)

International Trade and Finance: Key Policy Issues for the 112th Congress

This report highlights major international trade and finance issues Congress may address this year.
Date: January 7, 2011
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
International Trade and Finance: Key Policy Issues for the 112th Congress (open access)

International Trade and Finance: Key Policy Issues for the 112th Congress

The 112th Congress, in both its legislative and oversight capacities, faces numerous international trade and finance issues. In addition to the broader congressional oversight of the economic and political context of the current U.S. participation in the global economy, this report highlights major international trade and finance issues Congress may address this year and next.
Date: January 11, 2011
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
International Trade and Finance: Key Policy Issues for the 112th Congress (open access)

International Trade and Finance: Key Policy Issues for the 112th Congress

This report examines the trade relations between the United States, the European Union, and China.
Date: January 7, 2011
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
Trade Primer: Qs and As on Trade Concepts, Performance, and Policy (open access)

Trade Primer: Qs and As on Trade Concepts, Performance, and Policy

The 112th Congress has a full legislative and oversight agenda on international trade. The agenda may include considering legislation to implement pending free trade agreements with Panama, South Korea, and Colombia, enhanced enforcement of U.S. trade agreements, as well as oversight of the World Trade Organization's Doha Round and trade relations with China. This report provides information and context for many of these topics. The report is divided into four sections in a question-and-answer format: trade concepts, U.S. trade performance, formulation of U.S. trade policy, and trade and investment issues.
Date: January 5, 2011
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
The Future of the Eurozone and U.S. Interests (open access)

The Future of the Eurozone and U.S. Interests

Seventeen of the European Union's 27 member states share an economic and monetary union (EMU) with the euro as a single currency. These countries are effectively referred to as the Eurozone. What has become known as the Eurozone crisis began in early 2010 when financial markets were shaken by heightened concerns that the fiscal positions of a number of Eurozone countries, beginning with Greece, were unsustainable. This report provides background information and analysis on the future of the Eurozone in six parts, including discussions on the origins and design challenges of the Eurozone, proposals to define the Eurozone crisis, possible scenarios for the future of the Eurozone, and the implications of the Eurozone crisis for U.S. economic and political interests.
Date: January 10, 2011
Creator: Ahearn, Raymond J.; Jackson, James K.; Nelson, Rebecca M. & Weiss, Martin A.
Object Type: Report
System: The UNT Digital Library
The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III (open access)

The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III

The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Ly{alpha} forest, and a radial velocity search for planets around {approx}8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes 5-band imaging of roughly 5200 deg{sup 2} in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg{sup 2}, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameters pipeline, which has better determination of metallicity for high metallicity stars.
Date: January 1, 2011
Creator: Aihara, Hiroaki; Prieto, Carlos Allende; An, Deokkeun; Anderson, Scott F.; Aubourg, Eric; Balbinot, Eduardo et al.
Object Type: Article
System: The UNT Digital Library
Embodied Energy and Off-Grid Lighting (open access)

Embodied Energy and Off-Grid Lighting

The greenhouse gas (GHG) emissions from fuel-based lighting are substantial given the paltry levels of lighting service provided to users, leading to a great opportunity for GHG mitigation byencouraging the switch from fuel-based to rechargeable LED lighting. However, as with most new energy technology, switching to efficient lighting requires an up-front investment of energy(and GHGs) embedded in the manufacture of replacement components. We studied a population of off-grid lighting users in 2008-2009 in Kenya who were given the opportunity to adopt LEDlighting. Based on their use patterns with the LED lights and the levels of kerosene offset we observed, we found that the embodied energy of the LED lamp was"paid for" in only one month for grid charged products and two months for solar charged products. Furthermore, the energyreturn-on investment-ratio (energy produced or offset over the product's service life divided by energy embedded) for off-grid LED lighting ranges from 12 to 24, which is on par with on-gridsolar and large-scale wind energy. We also found that the energy embodied in the manufacture of a typical hurricane lantern is about one-half to one-sixth of that embodied in the particular LEDlights that we evaluated, indicating that the energy payback time would be …
Date: January 25, 2011
Creator: Alstone, Peter; Mills, Evan & Jacobson, Arne
Object Type: Report
System: The UNT Digital Library
Southwest Retort, Volume 63, Number 5, January 2011 (open access)

Southwest Retort, Volume 63, Number 5, January 2011

This publication of the Dallas-Fort Worth Section of the American Chemical Society includes information about research, prominent scientist, organizational business, and various other stories of interest to the community.
Date: January 2011
Creator: American Chemical Society. Dallas/Fort Worth Section.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library