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Observation of Single Top Quark Production with the D0 Detector

Description: We report on the observation of single top quark production by the D0 collaboration using a dataset of 2.3 fb{sup -1} collected at the Fermilab Tevatron p{bar p} collider. Several multivariate techniques are combined to separate the single top signal from backgrounds. The measured single top cross section is {sigma}{sub tb+tqb} = 3.94 {+-} 0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.9 x 10{sup -7}, corresponding to a 5.0 standard dev… more
Date: August 1, 2009
Creator: Schwienhorst, Reinhard; collaboration, for the D0 & U., /Michigan State
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Partner: UNT Libraries Government Documents Department
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Evolutionary algorithm for the neutrino factory front end design

Description: The Neutrino Factory is an important tool in the long-term neutrino physics program. Substantial effort is put internationally into designing this facility in order to achieve desired performance within the allotted budget. This accelerator is a secondary beam machine: neutrinos are produced by means of the decay of muons. Muons, in turn, are produced by the decay of pions, produced by hitting the target by a beam of accelerated protons suitable for acceleration. Due to the physics of this proc… more
Date: January 1, 2009
Creator: Poklonskiy, Alexey A.; U., /Michigan State; Neuffer, David & /Fermilab
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Partner: UNT Libraries Government Documents Department
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The Formation of Population III Binaries from Cosmological Initial Conditions

Description: Previous high resolution cosmological simulations predict the first stars to appear in the early universe to be very massive and to form in isolation. Here we discuss a cosmological simulation in which the central 50M{sub {circle_dot}} clump breaks up into two cores, having a mass ratio of two to one, with one fragment collapsing to densities of 10{sup -8}g cm{sup -3}. The second fragment, at a distance of {approx}800 astronomical units, is also optically thick to its own cooling radiation from… more
Date: August 26, 2010
Creator: Turk, Matthew J.; Abel, Tom; /KIPAC, Menlo Park; O'Shea, Brian W. & U., /Michigan State
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Partner: UNT Libraries Government Documents Department
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Luminosity Function of Faint Globular Clusters in M87

Description: We present the luminosity function to very faint magnitudes for the globular clusters in M87, based on a 30 orbit Hubble Space Telescope (HST) WFPC2 imaging program. The very deep images and corresponding improved false source rejection allow us to probe the mass function further beyond the turnover than has been done before. We compare our luminosity function to those that have been observed in the past, and confirm the similarity of the turnover luminosity between M87 and the Milky Way. We al… more
Date: July 14, 2006
Creator: Waters, Christopher Z.; Zepf, Stephen E.; U., /Michigan State; Lauer, Tod R.; /NOAO, Tucson; Baltz, Edward A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A Study of Neutron Proton Charge Exchange Scattering in the Momentum Range 50 - 200 GeV

Description: It is proposed to measure the neutron-proton charge-exchange cross-section in an on-line counter experiment for four-momentum transfers between .002 and 1.0 (GeV/c){sup 2}. The experiment will be performed in an intense neutron beam with a continuous momentum spectrum; data will be taken simultaneously for all momenta between 50 and 200 GeV/c. At a beam intensity of 10{sup 7} neutrons/pulse, the true data-collection rate will be about .5 per pulse. Approximately 90,000 events will be obtained. … more
Date: June 1, 1970
Creator: Reay, N. W.; Reibel, K.; Romanowski, T. A.; Stanton, N. R.; U., /Ohio State; Abolins, M. A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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YT: A Multi-Code Analysis Toolkit for Astrophysical Simulation Data

Description: The analysis of complex multiphysics astrophysical simulations presents a unique and rapidly growing set of challenges: reproducibility, parallelization, and vast increases in data size and complexity chief among them. In order to meet these challenges, and in order to open up new avenues for collaboration between users of multiple simulation platforms, we present yt (available at http://yt.enzotools.org/) an open source, community-developed astrophysical analysis and visualization toolkit. Ana… more
Date: June 23, 2011
Creator: Turk, Matthew J.; /San Diego, CASS; Smith, Britton D.; U., /Michigan State; Oishi, Jeffrey S.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. et al.
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Partner: UNT Libraries Government Documents Department
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Study of direct CP violation in B+- ---> J/psi K+- (pi+-) file decays

Description: The authors present a search for direct CP violation in B{sup {+-}} {yields} J/{psi}K{sup {+-}}{pi}{sup {+-}} decays. The event sample is selected from 2.8 fb{sup -1} of p{bar p} collisions recorded by D0 experiment in Run II of the Fermilab Tevatron Collider. The charge asymmetry A{sub CP}(B{sup +} {yields} J/{psi}K{sup +}) = +0.0075 {+-} 0.0061(stat.) {+-} 0.0027(syst.) is obtained using a sample of approximately 40 thousand B{sup {+-}} {yields} J/{psi}K{sup {+-}} decays. The achieved precisi… more
Date: February 1, 2008
Creator: Abazov, V. M.; /Dubna, JINR; Abbott, B.; U., /Oklahoma; Abolins, M.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Search for a heavy neutral gauge boson in the dielectron channel with 5.4~fb$^{-1}$ of $\mathbf{p\bar{p}}$ collisions at $\mathbf{\sqrt{s} = 1.96}$~TeV

Description: We report the results of a search for a heavy neutral gauge boson Z' decaying into the dielectron final state using data corresponding to an integrated luminosity of 5.4 fb{sup -1} collected by the D0 experiment at the Fermilab Tevatron Collider. No significant excess above the standard model prediction is observed in the dielectron invariant-mass spectrum. We set 95% C.L. upper limits on {sigma}(p{bar p} {yields} Z') x BR(Z' {yields} ee) depending on the dielectron invariant mass. These cross … more
Date: August 1, 2010
Creator: Abazov, Victor Mukhamedovich; Abazov, V.; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A. et al.
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Partner: UNT Libraries Government Documents Department
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Search for sneutrino production in $e\mu$ final states in 5.3 fb$^{-1}$ of $p\bar{p}$ collisions at $\sqrt(s) =1.96$ TeV

Description: We report the results of a search for R parity violating (RPV) interactions leading to the production of supersymmetric sneutrinos decaying into e{mu} final states using 5.3 fb{sup -1} of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. Having observed no evidence for production of e{mu} resonances, we set direct bounds on the RPV couplings {lambda}{prime}{sub 311} and {lambda}{sub 312} as a function of sneutrino mass.
Date: July 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Measurement of the $WZ\rightarrow \ell\nu\ell\ell$ cross section and limits on anomalous triple gauge couplings in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV

Description: The standard model (SM) of particle physics has been extensively tested in the past three decades and is found to be in excellent agreement with experimental observations. It is widely assumed, however, that the SM is only a low energy approximation of a more general theory. Therefore, any significant deviation from the SM predictions yields information on the nature of a more fundamental theory. Production of WZ pairs is the least studied diboson process within the SM, as it is a charged final… more
Date: June 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Search for flavor changing neutral currents in single top quark production using 2.3 fb$^-1$ of $p\bar{p}$ collisions

Description: We present a search for flavor changing neutral currents via quark-gluon couplings in a sample of single top quark final states corresponding to 2.3 fb{sup -1} of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. We select events containing a single top quark candidates with an additional jet, and obtain separation between signal and background using Bayesian neural networks. We find consistency between background expectation and observed data, and set limi… more
Date: June 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Search for Randall-Sundrum gravitons in the dielectron and diphoton final states with 5.4fb$^{-1}$ of data from $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

Description: Using 5.4 fb{sup -1} of integrated luminosity from p{bar p} collisions at {radical}s = 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider, we search for decays of the lightest Kaluza-Klein mode of the graviton in the Randall-Sundrum model to ee and {gamma}{gamma}. We set 95% C.L. lower limits on the mass of the lightest graviton between 560 GeV and 1050 GeV for values of the coupling k/{bar M}{sub Pl} between 0.01 and 0.1.
Date: April 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Evidence for an anomalous like-sign dimuon charge asymmetry

Description: We measure the charge asymmetry A of like-sign dimuon events in 6.1 fb{sup -1} of p{bar p} collisions recorded with the DO detector at a center of mass energy sqrt s = 1.96 TeV at the Fermilab Tevatron Collider.
Date: May 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Search for diphoton events with large missing transverse energy in 6.3 fb$^{-1}$ of $\mathbf{p\bar{p}}$ collisions at $\mathbf{\sqrt{s}=1.96}$~TeV

Description: We report a search for diphoton events with large missing transverse energy produced in p{bar p} collisions at {radical}s = 1.96 TeV. The data were collected with the D0 detector at the Fermilab Tevatron Collider, and correspond to 6.3 fb{sup -1} of integrated luminosity. The observed missing transverse energy distribution is well described by the standard model prediction, and 95% C.L. limits are derived on two realizations of theories beyond the standard model. In a gauge mediated supersymmet… more
Date: August 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Search for events with leptonic jets and missing transverse energy in $\mathbf{p\bar{p}}$ collisions at $\mathbf{\sqrt{s}=1.96}$ TeV

Description: We present the first search for pair production of isolated jets of charged leptons in association with a large imbalance in transverse energy in p{bar p} collisions using 5.8 fb{sup -1} of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider. No excess is observed above Standard Model background, and the result is used to set upper limits on the production cross section of pairs of supersymmetric chargino and neutralino particles as a function of 'dark-photon' m… more
Date: August 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Determination of the width of the top quark

Description: We extract the total width of the top quark, {Lambda}{sub t}, from the partial decay width {Lambda}(t {yields} Wb) measured using the t-channel cross section for single top quark production and from the branching fraction B(t {yields} Wb) measured in t{bar t} events using up to 2.3 fb{sup -1} of integrated luminosity collected by the D0 Collaboration at the Tevatron p{bar p} Collider. The result is {Lambda}{sub t} = 1.99{sub -0.55}{sup +0.69} GeV, which translates to a top-quark lifetime of {ta… more
Date: September 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Precise study of the $Z/\gamma^*$ boson transverse momentum distribution in $p\bar{p}$ collisions using a novel technique

Description: Using 7.3 fb{sup -1} of p{bar p} collisions collected by the D0 detector at the Fermilab Tevatron, we measure the distribution of the variable {phi}*{sub {eta}}, which probes the same physical effects as the Z/{gamma}* boson transverse momentum, but is less susceptible to the effects of experimental resolution and efficiency. A QCD prediction is found to describe the general features of the {phi}*{sub {eta}} distribution, but is unable to describe its detailed shape or dependence on boson rapid… more
Date: October 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Measurement of the normalized $Z/\gamma^* -> \mu^+\mu^-$ transverse momentum distribution in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

Description: We present a new measurement of the Z/{gamma}* transverse momentum distribution in the range 0-330 GeV, in proton anti-proton collisions at {radical}s = 1.96 TeV. The measurement uses 0.97 fb{sup -1} of integrated luminosity recorded by the D0 experiment and is the first using the Z/{gamma}* {yields} {mu}{sup +}{mu}{sup -} + X channel at this center-of-mass energy. This is also the first measurement of the Z/{gamma}* transverse momentum distribution that presents the result at the level of part… more
Date: June 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Measurement of $\boldsymbol{\ttb}$ production in the tau + jets channel using $\boldsymbol{p\bar{p}}$ collisions at $\boldsymbol{\sqrt{s} = 1.96}$~TeV

Description: We present a measurement of the t{bar t} production cross section multiplied by the branching ratio to tau lepton decaying semi-hadronically ({tau}{sub h}) plus jets, {sigma}(p{bar p} {yields} t{bar t} + X) {center_dot} BR(t{bar t} {yields} {tau}{sub h} + jets), at a center of mass energy {radical}s = 1.96 TeV using 1 fb{sup -1} of integrated luminosity collected with the D0 detector. Assuming a top quark mass of 170 GeV, we measure {sigma}{sub t{bar t}} {center_dot} BR{sub {tau}{sub h}+j} = 0.… more
Date: August 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Search for $ZH \rightarrow \ell^+\ell^-b\bar{b}$ production in $4.2$~fb$^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}=1.96~\TeV$

Description: We present a search for the standard model Higgs boson produced in association with a Z boson in 4.2 fb{sup -1} of p{bar p} collisions, collected with the D0 detector at the Fermilab Tevatron at {radical}s = 1.96 TeV. Selected events contain one reconstructed Z {yields} {ell}{sup +}{ell}{sup -} candidate and at least two jets, including at least one b-tagged jet. In the absence of an excess over the background expected from other standard model processes, limits on the ZH cross section multipli… more
Date: August 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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Partner: UNT Libraries Government Documents Department
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Status of the Super-B factory Design

Description: The SuperB international team continues to optimize the design of an electron-positron collider, which will allow the enhanced study of the origins of flavor physics. The project combines the best features of a linear collider (high single-collision luminosity) and a storage-ring collider (high repetition rate), bringing together all accelerator physics aspects to make a very high luminosity of 10{sup 36} cm{sup -2} sec{sup -1}. This asymmetric-energy collider with a polarized electron beam wil… more
Date: May 18, 2012
Creator: Wittmer, W.; U., /Michigan State; Bertsche, K.; Chao, A.; Novokhatski, A.; Nosochkov, Y. et al.
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Partner: UNT Libraries Government Documents Department
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Design and Implementation of the New D0 Level-1 Calorimeter Trigger

Description: Increasing luminosity at the Fermilab Tevatron collider has led the D0 collaboration to make improvements to its detector beyond those already in place for Run IIa, which began in March 2001. One of the cornerstones of this Run IIb upgrade is a completely redesigned level-1 calorimeter trigger system. The new system employs novel architecture and algorithms to retain high efficiency for interesting events while substantially increasing rejection of background. We describe the design and impleme… more
Date: September 1, 2007
Creator: Abolins, M.; Adams, M.; Adams, T.; Aguilo, E.; Anderson, J.; Bagby, L. et al.
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Partner: UNT Libraries Government Documents Department
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