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Empirical Study of Ne in H-Mode Pedestal in DIII-D (open access)

Empirical Study of Ne in H-Mode Pedestal in DIII-D

There is compelling empirical [1] and theoretical [2] evidence that the global confinement of H-mode discharges increases as the pedestal pressure or temperature increases. Therefore, confidence in the performance of future machines requires an ability to predict the pedestal conditions in those machines. At this time, both the theoretical and empirical understanding of transport in the pedestal are incomplete and are inadequate to predict pedestal conditions in present or future machines. Recent empirical results might be evidence of a fundamental relation between the electron temperature T{sub e} and electron density n{sub e} profiles in the pedestal. A data set from the ASDEX-Upgrade tokamak has shown that {eta}{sub e}, the ratio between the scale lengths of the n{sub e} and T{sub e} profiles, exhibits a value of about 2 throughout the pedestal, despite a large range of the actual density and temperature values [3]. Data from the DIII-D tokamak show that over a wide range of pedestal density, the width of the steep gradient region for the T{sub e} profile is about 1-2 times the corresponding width for the n{sub e} profile, where both widths are measured from the plasma edge [4]. Thus, the barrier in the density might form a …
Date: May 5, 2005
Creator: . Groebner, R. J.; Osborne, T. H.; Fenstermacher, M. E.; Leonard, A. W.; Mahdavi, M. A.; Snyder, P. B. et al.
System: The UNT Digital Library
QUANTITATIVE ANALYSES OF THE SEVERITY OF ATTACK ON CREVICE CORROSION SURFACES (open access)

QUANTITATIVE ANALYSES OF THE SEVERITY OF ATTACK ON CREVICE CORROSION SURFACES

None
Date: December 19, 2005
Creator: /a, n
System: The UNT Digital Library
CP VIOLATION HIGHLIGHTS: CIRCA 2005 (open access)

CP VIOLATION HIGHLIGHTS: CIRCA 2005

Recent highlights in CP violation phenomena, are reviewed. B-factory results imply that, CP-violation phase in the CKM matrix is the dominant contributor to the observed CP violation in K and B-physics. Deviations from the predictions of the CKM-paradigm due to beyond the Standard Model CP-odd phase are likely to be a small perturbation. Therefore, large data sample of clean B's will be needed. Precise determination of the unitarity triangle, along with time dependent CP in penguin dominated hadronic and radiative modes are discussed. Null tests in B, K and top-physics and separate determination of the K-unitarity triangle are also emphasized.
Date: February 27, 2005
Creator: A., SONI
System: The UNT Digital Library
Onset and Saturation of Ion Heating by Odd-parity Rotating-magnetic-fields in a Field-reversed Configuration (open access)

Onset and Saturation of Ion Heating by Odd-parity Rotating-magnetic-fields in a Field-reversed Configuration

Heating of figure-8 ions by odd-parity rotating magnetic fields (RMFο) applied to an elongated field-reversed configuration (FRC) is investigated. The largest energy gain occurs at resonances (s ≡ ω(sub)R⁄ω) of the RMFο frequency, ω(sub)R, with the figure-8 orbital frequency, ω, and is proportional to s^2 for s – even resonances and to s for s – odd resonances. The threshold for the transition from regular to stochastic orbits explains both the onset and saturation of heating. The FRC magnetic geometry lowers the threshold for heating below that in the tokamak by an order of magnitude.
Date: November 1, 2005
Creator: A.S. Landsman, S.A. Cohen, A.H. Glasser
System: The UNT Digital Library
Parameterizing the power spectrum: Beyond the truncated Taylor expansion (open access)

Parameterizing the power spectrum: Beyond the truncated Taylor expansion

The power spectrum is traditionally parameterized by a truncated Taylor series: ln P(k) = ln P{sub *} + (n{sub *} - 1) ln(k/k{sub *}) + 1/2 n'{sub *} ln{sup 2} (k/k{sub *}). It is reasonable to truncate the Taylor series if |n'{sub *} ln(k/k{sub *})| << |n{sub *} - 1|, but it is not if |n'{sub *} ln(k/k{sub *})| {approx}> |n{sub *} - 1|. We argue that there is no good theoretical reason to prefer |n'{sub *}| << |n{sub *} - 1|, and show that current observations are consistent with |n*{sub *} ln(k/k{sub *})| {approx} |n{sub *} - 1| even for |ln(k/k{sub *})| {approx} 1. Thus, there are regions of parameter space, which are both theoretically and observationally relevant, for which the traditional truncated Taylor series parameterization is inconsistent, and hence it can lead to incorrect parameter estimations. Motivated by this, we propose a simple extension of the traditional parameterization, which uses no extra parameters, but that, unlike the traditional approach, covers well motivated inflationary spectra with |n'{sub *}| {approx} |n{sub *} - 1|. Our parameterization therefore covers not only standard-slow-roll inflation models but also a much wider class of inflation models. We use this parameterization to perform a likelihood …
Date: July 1, 2005
Creator: Abazajian, Kevork; Kadota, Kenji & Stewart, Ewan D.
System: The UNT Digital Library
The Upgraded D0 detector (open access)

The Upgraded D0 detector

The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.
Date: July 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, D. L.; Adams, M. et al.
System: The UNT Digital Library
Measurement of inclusive differential cross sections for Upsilon(1S) production in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of inclusive differential cross sections for Upsilon(1S) production in p anti-p collisions at s**(1/2) = 1.96-TeV

The authors present measurements of the inclusive production cross sections of the {Upsilon}(1S) bottomonium state in p{bar p} collisions at {radical}s = 1.96 TeV. Using the {Upsilon}(1S) {yields} {mu}{sup +}{mu}{sup -} decay mode for a data sample of 159 {+-} 10 pb{sup -1} collected by the D0 detector at the Fermilab Tevatron collider, they determine the differential cross sections as a function of the {Upsilon}(1S) transverse momentum for three ranges of the {Upsilon}(1S) rapidity: 0 < |y{sup {Upsilon}}| {le} 0.6, 0.6 < |y{sup {Upsilon}}| {le} 1.2, and 1.2 < |y{sup {Upsilon}}| {le} 1.8.
Date: February 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Measurement of semileptonic branching fractions of B mesons to narrow D** states (open access)

Measurement of semileptonic branching fractions of B mesons to narrow D** states

None
Date: July 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Measurement of the p - anti-p ---> W gamma + X cross section at s**(1/2) = 1.96-TeV and WW gamma anomalous coupling limits (open access)

Measurement of the p - anti-p ---> W gamma + X cross section at s**(1/2) = 1.96-TeV and WW gamma anomalous coupling limits

The WW{gamma} triple gauge boson coupling parameters are studied using p{bar p} {yields} {ell}{nu}{gamma} + X({ell} = e, {mu}) events at {radical}s = 1.96 TeV. The data were collected with the D0 detector from an integrated luminosity of 162 pb{sup -1} delivered by the Fermilab Tevatron Collider. The cross section times branching fraction for p{bar p} {yields} W({gamma}) + X {yields} {ell}{nu}{gamma} + X with E{sub T}{sup {gamma}} > 8 GeV and {Delta}R{sub {ell}{gamma}} > 0.7 is 14.8 {+-} 1.6(stat) {+-} 1.0(syst) {+-} 1.0(lum) pb. The one-dimensional 95% confidence level limits on anomalous couplings are -0.88 < {Delta}{kappa}{sub {gamma}} < 0.96 and -0.20 < {lambda}{sub {gamma}} < 0.20.
Date: March 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Measurement of the t anti-t production cross section in p anti-p collisions at s**(1/2) = 1.96 = TeV using kinematic characteristics of lepton + jets events (open access)

Measurement of the t anti-t production cross section in p anti-p collisions at s**(1/2) = 1.96 = TeV using kinematic characteristics of lepton + jets events

We present a measurement of the top quark pair (t{bar t}) production cross section ({sigma}{sub t{bar t}}) in p{bar p} collisions at a center-of-mass energy of 1.96 TeV using 230 pb{sub -1} of data collected by the D0 detector at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), large missing transverse energy, and at least four jets, and extract the t{bar t} content of the sample based on the kinematic characteristics of the events. For a top quark mass of 175 GeV, we measure {sigma}{sub t{bar t}} = 6.7{sub -1.3}{sup +1.4}(stat){sub -1.1}{sup +1.6}(syst) {+-} 0.4(lumi)pb, in good agreement with the standard model prediction.
Date: April 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Measurement of the t anti-t production cross section in p anti-p collisions at s**(1/2) = 1.96-TeV using lepton + jets events with lifetime b-tagging (open access)

Measurement of the t anti-t production cross section in p anti-p collisions at s**(1/2) = 1.96-TeV using lepton + jets events with lifetime b-tagging

We present a measurement of the top quark pair (t{bar t}) production cross section ({sigma}{sub t{bar t}}) in p{bar p} collisions at {radical}s = 1.96 TeV using 230 pb{sup -1} of data collected by the D0 experiment at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), missing transverse energy, and jets in the final state. We employ lifetime-based b-jet identification techniques to further enhance the t{bar t} purity of the selected sample. For a top quark mass of 175 GeV, we measure {sigma}{sub t{bar t}} = 8.6{sub -1.5}{sup +1.6}(stat. + syst.) {+-} 0.6 (lumi.) pb, in agreement with the standard model expectation.
Date: April 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Measurement of the t anti-t production cross section in p anti-p collistions at s**(1/2) = 1.96-TeV in dilepton final states (open access)

Measurement of the t anti-t production cross section in p anti-p collistions at s**(1/2) = 1.96-TeV in dilepton final states

The authors present a measurement of the top quark pair (t{bar t}) production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using events with two charged leptons in the final state. This analysis utilizes an integrated luminosity of 224-243 pb{sup -1} collected with the D0 detector at the Fermilab Tevatron Collider. They observe 13 events in the e{sup +}e{sup -}, e{mu} and {mu}{sup +} {mu}{sup -} channels with an expected background of 3.2 {+-} 0.7 events. For a top quark mass of 175 GeV, we measure a t{bar t} production cross section of {sigma}{sub t{bar t}} = 8.6{sub -2.7}{sup +3.2}(stat) {+-} 1.1(syst) {+-} 0.6(lumi) pb, consistent with the standard model prediction.
Date: May 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Production of WZ events in p anti-p collisions at s**(1/2) = 1.96-TeV and limits on anomalous WWZ couplings (open access)

Production of WZ events in p anti-p collisions at s**(1/2) = 1.96-TeV and limits on anomalous WWZ couplings

The authors present results from a search for WZ production with subsequent decay to {ell}{nu}{ell}'{bar {ell}}' ({ell} and {ell}' = e or {mu}) using 0.30 fb{sup -1} of data collected by the D0 experiment between 2002 and 2004 at the Tevatron. Three events with WZ decay characteristics are observed. With an estimated background of 0.71 {+-} 0.08 events, we measure the WZ production cross section to be 4.5{sub -2.6}{sup +3.8} pb, with a 95% C.L. upper limit of 13.3 pb. The 95% C.L. limits for anomalous WWZ couplings are found to be -2.0 < {Delta}{kappa}{sub Z} < 2.4 for form factor scale {Lambda} = 1 TeV, and -0.48 < {lambda}{sub Z} < 0.48 and -0.49 < {Delta}g{sub 1}{sup Z} < 0.66 for {Lambda} = 1.5 TeV.
Date: April 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Search for large extra spatial dimensions in dimuon production at D0 (open access)

Search for large extra spatial dimensions in dimuon production at D0

We present the results of a search for the e.ects of large extra spatial dimensions in p{bar p} collisions at {radical}s = 1.96 TeV in events containing a pair of energetic muons. The data correspond to 246 pb{sup -1} of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. Good agreement with the expected background was found, yielding no evidence for large extra dimensions. We set 95% C.L. lower limits on the fundamental Planck scale between 0.85 TeV and 1.27 TeV within several formalisms. These are the most stringent limits achieved in the dimuon channel to date.
Date: June 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Search for neutral supersymmetric Higgs bosons in multijet events at s**(1/2) = 1.96-TeV (open access)

Search for neutral supersymmetric Higgs bosons in multijet events at s**(1/2) = 1.96-TeV

We have performed a search for neutral Higgs bosons produced in association with bottom quarks in p{bar p} collisions, using 260 pb{sup -1} of data collected with the D0 detector in Run II of the Fermilab Tevatron Collider. The cross sections for these processes are enhanced in many extensions of the standard model (SM), such as in its minimal supersymmetric extension at large tan {beta}. The results of our analysis agree with expectations from the SM, and we use our measurements to set upper limits on the production of neutral Higgs bosons in the mass range of 90 to 150 GeV.
Date: April 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Search for right-handed W bosons in top quark decay (open access)

Search for right-handed W bosons in top quark decay

None
Date: May 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Search for single top quark production in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for single top quark production in p anti-p collisions at s**(1/2) = 1.96-TeV

We present a search for electroweak production of single top quarks in the s-channel and t-channel using neural networks for signal-background separation. We have analyzed 230 pb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron Collider at a center-of-mass energy of 1.96 TeV and find no evidence for a single top quark signal. The resulting 95% confidence level upper limits on the single top quark production cross sections are 6.4 pb in the s-channel and 5.0 pb in the t-channel.
Date: May 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Search for supersymmetry via associated production of charginos and neutralinos in final states with three leptons (open access)

Search for supersymmetry via associated production of charginos and neutralinos in final states with three leptons

None
Date: April 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Search for the Higgs boson in H ---> WW(*) decays in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for the Higgs boson in H ---> WW(*) decays in p anti-p collisions at s**(1/2) = 1.96-TeV

We present a search for the standard model Higgs boson in H {yields} WW{sup (*)} decays with e{sup +}e{sup -}, e{sup {+-}}{mu}{sup {-+}} and {mu}{sup +}{mu}{sup -} final states in p{bar p} collisions at a center-of-mass energy of {radical}s = 1.96 TeV. The data, collected from April 2002 to June 2004 with the D0 detector, correspond to an integrated luminosity of 300-325 pb{sup -1}, depending on the final state. The number of events observed is consistent with the expectation from backgrounds. Limits from the combination of all three channels on the Higgs production cross section times branching ratio {sigma} x BR(H {yields} WW{sup (*)}) are presented.
Date: August 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Study of Z gamma events and limits on anomalous Z Z gamma and Z gamma gamma couplings in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Study of Z gamma events and limits on anomalous Z Z gamma and Z gamma gamma couplings in p anti-p collisions at s**(1/2) = 1.96-TeV

The authors present a measurement of the Z{gamma} production cross section and limits on anomalous ZZ{gamma} and Z{gamma}{gamma} couplings for form-factor scales of {Lambda} = 750 and 1000 GeV. The measurement is based on 138 (152) candidate events in the ee{gamma} ({mu}{mu}{gamma}) final state using 320 (290) pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV. The 95% C.L. limits on real and imaginary parts of individual anomalous couplings are |h{sub 10,30}{sup Z}| < 0.23, |h{sub 20,40}{sup Z}| < 0.020, |h{sub 10,30}{gamma}| < 0.23, and |h{sub 20,40}{gamma}| < 0.019 for {Lambda} = 1000 GeV.
Date: February 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
The Muon system of the run II D0 detector (open access)

The Muon system of the run II D0 detector

The authors describe the design, construction and performance of the upgraded D0 muon system for Run II of the Fermilab Tevatron collider. Significant improvements have been made to the major subsystems of the D0 muon detector: trigger scintillation counters, tracking detectors, and electronics. The Run II central muon detector has a new scintillation counter system inside the iron toroid and an improved scintillation counter system outside the iron toroid. In the forward region, new scintillation counter and tracking systems have been installed. Extensive shielding has been added in the forward region. A large fraction of the muon system electronics is also new.
Date: March 1, 2005
Creator: Abazov, V. M.; Acharya, B. S.; Alexeev, G. D.; Alkhazov, G.; Anosov, V. A.; Baldin, B. et al.
System: The UNT Digital Library
A Search for gravitational waves associated with the gamma ray burst GRB030329 using the LIGO detectors (open access)

A Search for gravitational waves associated with the gamma ray burst GRB030329 using the LIGO detectors

We have performed a search for bursts of gravitational waves associated with the very bright Gamma Ray Burst GRB030329, using the two detectors at the LIGO Hanford Observatory. Our search covered the most sensitive frequency range of the LIGO detectors (approximately 80-2048 Hz), and we specifically targeted signals shorter than {approx_equal}150 ms. Our search algorithm looks for excess correlated power between the two interferometers and thus makes minimal assumptions about the gravitational waveform. We observed no candidates with gravitational wave signal strength larger than a pre-determined threshold. We report frequency dependent upper limits on the strength of the gravitational waves associated with GRB030329. Near the most sensitive frequency region, around {approx_equal}250 Hz, our root-sum-square (RSS) gravitational wave strain sensitivity for optimally polarized bursts was better than h{sub RSS} {approx_equal} 6 x 10{sup -21} Hz{sup -1/2}. Our result is comparable to the best published results searching for association between gravitational waves and GRBs.
Date: January 1, 2005
Creator: Abbott, B.; Abbott, R.; Adhikari, R.; Ageev, A.; Allen, B.; Amin, R. et al.
System: The UNT Digital Library
The Dynamic Response of Thick-Liquid Shielding in Z-IFE Reactors (open access)

The Dynamic Response of Thick-Liquid Shielding in Z-IFE Reactors

A major concern in the design of thick-liquid protected inertial fusion reactors of all types is the dynamic response of the shielding liquid to the pulsed explosions. Induced liquid motion can stress and damage solid chamber structures such as the firstwall. In a z-pinch based inertial fusion (Z-IFE) reactor this issue becomes particularly critical due to the relatively large proposed target yields of several GJ. In this paper we summarize an analysis of the liquid response taking into account ablation of target facing surfaces, pocket venting, and neutron isochoric heating. The impact of varying several reactor parameters is also discussed.
Date: October 5, 2005
Creator: Abbott, R P
System: The UNT Digital Library
Provably Secure Password-based Authentication in TLS (open access)

Provably Secure Password-based Authentication in TLS

In this paper, we show how to design an efficient, provably secure password-based authenticated key exchange mechanism specifically for the TLS (Transport Layer Security) protocol. The goal is to provide a technique that allows users to employ (short) passwords to securely identify themselves to servers. As our main contribution, we describe a new password-based technique for user authentication in TLS, called Simple Open Key Exchange (SOKE). Loosely speaking, the SOKE ciphersuites are unauthenticated Diffie-Hellman ciphersuites in which the client's Diffie-Hellman ephemeral public value is encrypted using a simple mask generation function. The mask is simply a constant value raised to the power of (a hash of) the password.The SOKE ciphersuites, in advantage over previous pass-word-based authentication ciphersuites for TLS, combine the following features. First, SOKE has formal security arguments; the proof of security based on the computational Diffie-Hellman assumption is in the random oracle model, and holds for concurrent executions and for arbitrarily large password dictionaries. Second, SOKE is computationally efficient; in particular, it only needs operations in a sufficiently large prime-order subgroup for its Diffie-Hellman computations (no safe primes). Third, SOKE provides good protocol flexibility because the user identity and password are only required once a SOKE ciphersuite has …
Date: December 20, 2005
Creator: Abdalla, Michel; Emmanuel, Bresson; Chevassut, Olivier; Moeller,Bodo & Pointcheval, David
System: The UNT Digital Library