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Pressurized fluidized-bed combustion technology exchange workshop

Description: The pressurized fluidized-bed combustion technology exchange workshop was held June 5 and 6, 1979, at The Meadowlands Hilton Hotel, Secaucus, New Jersey. Eleven papers have been entered individually into EDB and ERA. The papers include reviews of the US DOE and EPRI programs in this area and papers by Swedish, West German, British and American organizations. The British papers concern the joint program of the USA, UK and FRG at Leatherhead. The key factor in several papers is the use of fluidized bed combustors, gas turbines, and steam turbines in combined-cycle power plants. One paper examines several combined-cycle alternatives. (LTN)
Date: April 1, 1980
Creator: ,
Partner: UNT Libraries Government Documents Department

Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron

Description: We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum p{sub T} > 0.5 GeV/c, pseudorapidity |{eta}| < 1) produced in association with large transverse momentum jets ({approx}2.2 fb{sup -1}) or with Drell-Yan lepton-pairs ({approx}2.7 fb{sup -1}) in the Z-boson mass region (70 < M(pair) < 110 GeV/c{sup 2}) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-p{sub T} jet production) in each event to define three regions of {eta}-{phi} space; toward, away, and transverse, where {phi} is the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-p{sub T} jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide data that can be used to test and improve the QCD Monte-Carlo models of the underlying event that are used to simulate hadron-hadron collisions.
Date: March 1, 2010
Creator: ,; Aaltonen, T.; Adelman, J.; Gonzalez, B.Alvarez; Amerio, S.; Amidei, D. et al.
Partner: UNT Libraries Government Documents Department

Nuclear physics with a medium-energy Electron-Ion Collider

Description: A polarized ep/eA collider (Electron-Ion Collider, or EIC) with variable center-of-mass energy {radical}s {approx} 20-70 GeV and a luminosity {approx}10{sup 34} cm{sup -2} s{sup -1} would be uniquely suited to address several outstanding questions of Quantum Chromodynamics (QCD) and the microscopic structure of hadrons and nuclei: (i) the three-dimensional structure of the nucleon in QCD (sea quark and gluon spatial distributions, orbital motion, polarization, correlations); (ii) the fundamental color fields in nuclei (nuclear parton densities, shadowing, coherence effects, color transparency); (iii) the conversion of color charge to hadrons (fragmentation, parton propagation through matter, in-medium jets). We briefly review the conceptual aspects of these questions and the measurements that would address them, emphasizing the qualitatively new information that could be obtained with the collider. Such a medium-energy EIC could be realized at Jefferson Lab after the 12 GeV Upgrade (MEIC), or at Brookhaven National Lab as the low-energy stage of eRHIC.
Date: June 1, 2012
Creator: A. Accardi, V. Guzey, A. Prokudin, C. Weiss
Partner: UNT Libraries Government Documents Department

Physical effects of infrared quark eigenmodes in LQCD

Description: A truncated determinant algorithm is used to study the physical effects of the quark eigenmodes associated with eigenvalues below 300 MeV. This initial study focuses on coarse lattices (with O(a{sup 2}) improved gauge action), light internal quark masses and large physical volumes. Four bellweather full QCD processes are discussed: topological charge distributions, the eta prime propagator, string breaking as observed in the static energy and the rho decay into two pions.
Date: October 7, 1999
Creator: A. Duncan, E. Eichten and H. Thacker
Partner: UNT Libraries Government Documents Department

Unquenched Studies Using the Truncated Determinant Algorithm

Description: A truncated determinant algorithm is used to study the physical effects of the quark eigenmodes associated with eigenvalues below 420 MeV. This initial high statistics study focuses on coarse (6{sup 4}) lattices (with O(a{sup 2}) improved gauge action), light internal quark masses and large physical volumes. Three features of full QCD are examined: topological charge distributions, string breaking as observed in the static energy and the eta prime mass.
Date: November 29, 2001
Creator: A. Duncan, E. Eichten and H. Thacker
Partner: UNT Libraries Government Documents Department


Description: 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
Partner: UNT Libraries Government Documents Department

A Rosetta Stone Relating Conventions In Photo-Meson Partial Wave Analyses

Description: A new generation of complete experiments in pseudoscalar meson photo-production is being pursued at several laboratories. While new data are emerging, there is some confusion regarding definitions of asymmetries and the conventions used in partial wave analyses (PWA). We present expressions for constructing asymmetries as coordinate-system independent ratios of cross sections, along with the names used for these ratios by different PWA groups.
Date: April 1, 2012
Creator: A.M. Sandorfi, B. Dey, A. Sarantsev, L. Tiator, R. Workman
Partner: UNT Libraries Government Documents Department

Nonforward parton distributions

Description: Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive electroproduction processes require a generalization of usual parton distributions for the case when long-distance information is accumulated in nonforward matrix elements <p{prime}{vert_bar}O(0,x){vert_bar}p> of quark and gluon light-cone operators. They describe two types of nonperturbative functions parameterizing such matrix elements: double distributions F(x,y;t) and nonforward distribution functions F{_}/zeta (X;t), discuss their spectral properties, evolution equations which they satisfy, basic uses and general aspects of factorization for hard exclusive processes.
Date: April 1, 1997
Creator: A.Radyushkin
Partner: UNT Libraries Government Documents Department

F(1) for B (forward) D*ln from lattice QCD

Description: The authors would like to determine |V{sub cb}| from the exclusive semi-leptonic decay B{yields}D*lv. The differential decay rate is d{Lambda}/dw = G{sub F}{sup 2}/4{pi}{sup 3}(w{sup 2}-1){sup 1/2}m{sub D*}{sup 3} (m{sub B}-m{sub D*}){sup 2}G(w)|V{sub cb}|{sup 2}|F{sub B{yields}D*}(w)|{sup 2}, where w = v {center_dot} v{prime} and G(1) = 1. At zero recoil (w = 1) heavy-quark symmetry requires F{sub B{yields}D*}(1) to be close to 1. So, |V{sub cb}| is determined by dividing measurements of d{Lambda}/dw by the phase space and well-known factors, and extrapolating to w {yields} 1. This yields |V{sub cb}|F{sub B{yields}D*}(1), and F{sub B{yields}D*}(1) is taken from ''theory''. To date models [1] or a combination of a rigorous inequality plus judgement [2] have been used to estimate F{sub B{yields}D*}(1) - 1. In this work [3] they calculate F{sub B{yields}D*}(1) with lattice gauge theory, in the so-called quenched approximation, but the uncertainty from quenching is included in the error budget.
Date: July 12, 2002
Creator: A.S. Kronfeld, P.B. Mackenzie and J.N. Simone
Partner: UNT Libraries Government Documents Department

QCD sum rule calculation of {gamma}{gamma}{sup *} {r_arrow} {pi}{sup 0} transition form factor

Description: The authors develop a QCD sum rule analysis of the form factor F{sub {gamma}{sup *}{gamma}{sup *}{pi}{sup 0}}(q{sup 2},Q{sup 2}) in the region where virtuality of one of the spacelike photons is small q{sup 2} {much_lt} 1 GeV{sup 2} while another is large: Q{sup 2} {approx_gt} 1 GeV{sup 2}. They construct the operator product expansion suitable for this kinematic situation and obtain a QCD sum rule for F{sub {gamma}{sup *}{gamma}{sup *}{pi}{sup 0}}(0, Q{sup 2}). Their results confirm expectation that the momentum transfer dependence of F{sub {gamma}{sup *}{gamma}{sup *}{pi}{sup 0}}(0,Q{sup 2}) is close to interpolation between its Q{sup 2}=0 value fixed by the axial anomaly and Q{sup {minus}2} pQCD behavior for large Q{sup 2}. Their approach, in contrast to pQCD, does not require additional assumptions about the shape of the pion distribution amplitude {var_phi}{sub {pi}}(x). The absolute value of the 1/Q{sup 2} term obtained in this paper favors {var_phi}{sub {pi}}(x) close to the asymptotic form {var_phi}{sub {pi}}{sup as}(x) = 6f{sub {pi}}x(1{minus}x).
Date: November 1, 1995
Creator: A.V.Radyushkin & R.T.Ruskov
Partner: UNT Libraries Government Documents Department

Alignment validation

Description: The four experiments, ALICE, ATLAS, CMS and LHCb are currently under constructionat CERN. They will study the products of proton-proton collisions at the Large Hadron Collider. All experiments are equipped with sophisticated tracking systems, unprecedented in size and complexity. Full exploitation of both the inner detector andthe muon system requires an accurate alignment of all detector elements. Alignmentinformation is deduced from dedicated hardware alignment systems and the reconstruction of charged particles. However, the system is degenerate which means the data is insufficient to constrain all alignment degrees of freedom, so the techniques are prone to converging on wrong geometries. This deficiency necessitates validation and monitoring of the alignment. An exhaustive discussion of means to validate is subject to this document, including examples and plans from all four LHC experiments, as well as other high energy experiments.
Date: September 6, 2008
Creator: ALICE; ATLAS; CMS; LHCb & Golling, Tobias
Partner: UNT Libraries Government Documents Department


Description: We study the fragmentation of a transversely polarized quark into a non-collinear (k{perpendicular} {ne} 0) spinless hadron and the fragmentation of an unpolarized quark into a non collinear transversely polarized spin 1/2 baryon. These nonperturbative properties are described by spin and k{perpendicular} dependent fragmentation functions and are revealed in the observation of single spin asymmetries. Recent data on the production of pions in polarized semi-inclusive DIS and long known data on A polarization in unpolarized p-N processes are considered: these new fragmentation functions can describe the experimental results and the single spin effects in the quark fragmentation turn out to be surprisingly large.
Date: April 23, 2001
Partner: UNT Libraries Government Documents Department


Description: The massively parallel computer QCDOC (QCD On a Chip) of the RIKEN BNL Research Center (RI3RC) will provide ten-teraflop peak performance for lattice gauge calculations. Lattice groups from both Columbia University and RBRC, along with assistance from IBM, jointly handled the design of the QCDOC. RIKEN has provided $5 million in funding to complete the machine in 2003. Some fraction of this computer (perhaps as much as 10%) might be made available for large-scale computations in areas of theoretical nuclear physics other than lattice gauge theory. The purpose of this workshop was to investigate the feasibility and possibility of using a supercomputer such as the QCDOC for lattice, general nuclear theory, and other calculations. The lattice applications to nuclear physics that can be investigated with the QCDOC are varied: for example, the light hadron spectrum, finite temperature QCD, and kaon ({Delta}I = 1/2 and CP violation), and nucleon (the structure of the proton) matrix elements, to name a few. There are also other topics in theoretical nuclear physics that are currently limited by computer resources. Among these are ab initio calculations of nuclear structure for light nuclei (e.g. up to {approx}A = 8 nuclei), nuclear shell model calculations, nuclear hydrodynamics, heavy ion cascade and other transport calculations for RHIC, and nuclear astrophysics topics such as exploding supernovae. The physics topics were quite varied, ranging from simulations of stellar collapse by Douglas Swesty to detailed shell model calculations by David Dean, Takaharu Otsuka, and Noritaka Shimizu. Going outside traditional nuclear physics, James Davenport discussed molecular dynamics simulations and Shailesh Chandrasekharan presented a class of algorithms for simulating a wide variety of femionic problems. Four speakers addressed various aspects of theory and computational modeling for relativistic heavy ion reactions at RHIC. Scott Pratt and Steffen Bass gave general overviews of how qualitatively ...
Date: September 26, 2002
Partner: UNT Libraries Government Documents Department


Description: The Relativistic Heavy Ion Collider (RHIC) at BNL is the world's only polarized proton-proton collider. Collisions at center-of-mass energies up to 500 GeV and beam polarizations approaching 70% (longitudinal or transverse) are provided to two experiments, STAR and PHENIX, at luminosities {ge} 10{sup 32}/cm{sup 2}/sec. Transverse polarized beam has also been provided to the BRAHMS experiment. Measurements that bear on the important question of the spin content of the nucleon are beginning to appear. Over the next 10 years, as the performance of polarized proton running at RHIC is further developed, the Spin Physics program at RHIC will provide definitive measurements of the contributions to the proton's spin of the gluon, the sea quarks and the orbital motion of the partons in the proton's wave function. We plan to extend the reach of our study of the role of spin in QCD with the development of ''eRHIC'', which will provide polarized e-p collisions to a new detector.
Date: October 2, 2006
Partner: UNT Libraries Government Documents Department


Description: The role of proton-nucleus (p-A) collisions in the study of strong interactions has a long history. It has been an important testing ground for QCD. At RHIC p-A studies have been recognized since the beginning as important elements of the program. These include so-called baseline measurements in cold nuclear matter, essential (along with p-p studies) to a systematic study of QCD at high temperatures and densities in the search for the quark gluon plasma. Also accessible is a study of QCD in the small x (parton saturation) regime, complementary to physics accessible in high-energy e-p and e-A collisions. The role of p-A physics at RHIC was reviewed and brought into sharp focus at a workshop conducted in October 2000 at BNL; the agenda is shown in Appendix 1. This document summarizes the case for p-A at RHIC during the period covered by the next Nuclear Physics Long Range Plan. In subsequent sections we cover the Physics Issues, Experiment Run Plans and Schedule, Detector Upgrade Issues, and Machine Issues & Upgrades.
Date: March 1, 2001
Creator: ARONSON,S.H. & PENG,J.C.
Partner: UNT Libraries Government Documents Department


Description: The sensitivity of the ATLAS detector to the discovery of a heavy charged Higgs boson is presented. Assuming a heavy SUSY spectrum, the most promising channels above the top quark mass are H{sup {+-}} {yields} tb and h{sup {+-}} {yields} {tau}{sup {+-}}{nu}{sub {tau}} which provide coverage in the low and high tan {beta} regions up to {approx} 600 GeV. The achievable precisions on the charged Higgs mass and tan {beta} determination are also discussed. The H{sup {+-}} {yields} W{sup {+-}}h{sup 0} channel, though restricted to a small MSSM parameter space, shows a viable signal in NMSSM where the parameter space is less constrained. The observation of the channel H{sup -} {yields} {tau}{sub L}{sup -} {nu}{sub {tau}} + c.c. may constitute a distinctive evidence for models with singlet neutrinos in large extra dimensions.
Date: February 1, 2002
Partner: UNT Libraries Government Documents Department

Alignment strategy for the ATLAS tracker

Description: The ATLAS experiment is a multi-purpose particle detector that will study high-energy particle collisions produced by the Large Hadron Collider. For the reconstruction of charged particles, and their production and their decay vertices, ATLAS is equipped with a sophisticated tracking system, unprecedented in size and complexity. Full exploitation of both the Inner Detector and the muon spectrometer requires an accurate alignment. The challenge of aligning the ATLAS tracking devices is discussed, and the ATLAS alignment strategy is presented and illustrated with both data and Monte Carlo results.
Date: September 23, 2007
Creator: ATLAS & Golling, T.
Partner: UNT Libraries Government Documents Department

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

Description: The Large Hadron Collider (LHC) at CERN promises a major step forward in the understanding of the fundamental nature of matter. The ATLAS experiment is a general-purpose detector for the LHC, whose design was guided by the need to accommodate the wide spectrum of possible physics signatures. The major remit of the ATLAS experiment is the exploration of the TeV mass scale where groundbreaking discoveries are expected. In the focus are the investigation of the electroweak symmetry breaking and linked to this the search for the Higgs boson as well as the search for Physics beyond the Standard Model. In this report a detailed examination of the expected performance of the ATLAS detector is provided, with a major aim being to investigate the experimental sensitivity to a wide range of measurements and potential observations of new physical processes. An earlier summary of the expected capabilities of ATLAS was compiled in 1999 [1]. A survey of physics capabilities of the CMS detector was published in [2]. The design of the ATLAS detector has now been finalised, and its construction and installation have been completed [3]. An extensive test-beam programme was undertaken. Furthermore, the simulation and reconstruction software code and frameworks have been completely rewritten. Revisions incorporated reflect improved detector modelling as well as major technical changes to the software technology. Greatly improved understanding of calibration and alignment techniques, and their practical impact on performance, is now in place. The studies reported here are based on full simulations of the ATLAS detector response. A variety of event generators were employed. The simulation and reconstruction of these large event samples thus provided an important operational test of the new ATLAS software system. In addition, the processing was distributed world-wide over the ATLAS Grid facilities and hence provided an important test of the ATLAS ...
Date: November 28, 2011
Creator: Aad, G.; Abat, E.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A. et al.
Partner: UNT Libraries Government Documents Department

Search for High-Mass States with One Lepton Plus Missing Transverse Momentum in Proton-Proton Collisions at $\sqrt{s} with the ATLAS Detector

Description: The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W{prime},W*), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of ppcollisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb{sup -1}. No excess beyond standard model expectations is observed. A W{prime} with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W* (charged chiral boson) for masses below 1.35 TeV.
Date: June 20, 2012
Creator: Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdelalim, Ahmed Ali; Abdesselam, Abdelouahab; Abdinov, Ovsat et al.
Partner: UNT Libraries Government Documents Department

Measurement of Lifetime and Decay-Width Difference in B0s -> J/psi phi Decays

Description: The authors measure the mean lifetime, {tau} = 2/({Lambda}{sub L} + {Lambda}{sub H}), and the decay-width difference, {Delta}{Lambda} = {Lambda}{sub L} - {Lambda}{sub H}, of the light and heavy mass eigenstates of the B{sub s}{sup 0} meson, B{sub sL}{sup 0} and B{sub sH}{sup 0}, in B{sub s}{sup 0} {yields} J/{psi}{phi} decays using 1.7 fb{sup -1} of data collected with the CDF II detector at the Fermilab Tevatron p{bar p} collider. Assuming CP conservation, a good approximation for the B{sub s}{sup 0} system in the standard model, they obtain {Delta}{Lambda} = 0.076{sub -0.063}{sup +0.059}(stat.) {+-} 0.006(syst.) ps{sup -1} and {tau} = 1.52 {+-} 0.04(stat.) {+-} 0.02(syst.) ps, the most precise measurements to date. The constraints on the weak phase and {Delta}{Lambda} are consistent with CP conservation.
Date: December 1, 2007
Creator: Aaltonen, : T.
Partner: UNT Libraries Government Documents Department