Advances in the understanding and operations of superconducting colliders (open access)

Advances in the understanding and operations of superconducting colliders

Chromaticity drift during injection is a well-known phenomenon in superconducting colliders, such as the Tevatron, HERA and RHIC. Imperfect compensation of the drift effects can contribute to beam loss and emittance growth. It is caused by the drift of the sextupole component in the dipole magnets due to current redistribution in its superconducting coils. Recently extensive studies of chromaticity drift were conducted at the Tevatron, aiming at the improvement of the luminosity performance in the ongoing run II. These studies included not only beam experiments, but also extensive off-line magnetic measurements on spare Tevatron dipoles. Less known, until recently, is that chromaticity drift is often accompanied by tune and coupling drift. This was recently discovered in the Tevatron. We believe that these effects are the product of systematic beam offset in conjunction with the sextupole drifts (and their compensation in the chromaticity correctors). These discoveries are most relevant to the upcoming LHC, where the drift effects will have even more dramatic consequences given the high beam current. It is therefore not a surprise that CERN has been the source of major advances in the understanding of dynamic effects during the LHC superconducting magnet development. The following will briefly review the …
Date: May 1, 2005
Creator: Annala, G.; Bauer, P.; Bottura, L.; Martens, M. A.; Sammut, N.; Velev, G. et al.
System: The UNT Digital Library
Study of the decay asymmetry parameter and CP violation parameter in the Lambda(c)+ ---> Lambda pi+ decay (open access)

Study of the decay asymmetry parameter and CP violation parameter in the Lambda(c)+ ---> Lambda pi+ decay

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the weak decay-asymmetry parameter a{sub {Lambda}{sub c}} in {Lambda}{sub c}{sup +} {yields} {Lambda}{pi}{sup +} decay. Comparing particle with antiparticle decays, we obtain the first measurement of the CP violation parameter {Alpha} {triple_bond} a{sub {Lambda}{sub c}} + a{sub {ovr {Lambda}{sub c}}}/a{sub {Lambda}{sub c}} - a{sub {ovr {Lambda}{sub c}}}. We obtain a{sub {Lambda}{sub c}} = -0.78 {+-} 0.16 {+-} 0.13 and {Alpha} = -0.07 {+-} 0.19 {+-} 0.12 where errors are statistical and systematic.
Date: September 1, 2005
Creator: Link, J. M.; Yager, P. M.; /UC, Davis; Anjos, J. C.; Bediaga, I.; Castromonte, C. et al.
System: The UNT Digital Library
Measurement of the resonance parameters of the chi(1)(1**3P(1)) and chi(2)(1**3P(2)) states of charmonium formed in antiproton-proton annihilations (open access)

Measurement of the resonance parameters of the chi(1)(1**3P(1)) and chi(2)(1**3P(2)) states of charmonium formed in antiproton-proton annihilations

The authors have studied the {sup 3}P{sub J} ({chi}{sub e}) states of charmonium in formation by antiproton-proton annihilations in experiment E835 at the Fermilab Antiproton Source. The authors report new measurements of the mass, width, and B({chi}{sub cJ} {yields} {bar p}p) x {Lambda}({chi}{sub eJ} {yields} J/{psi} + anything) for the {chi}{sub c1} and {chi}{sub c2} by means of the inclusive reaction {bar p}p {yields} {chi}{sub cJ} {yields} J/{psi} + anything {yields} (e{sup +}e{sup -}) + anything. Using the subsample of events where {chi}{sub cJ} {yields} {gamma} + J/{psi} {yields} {gamma} + (e{sup +}e{sup -}) is fully reconstructed, we derive B({chi}{sub cJ} {yields} {bar p}p) x {Lambda}({chi}{sub cJ} {yields} J/{psi} + {gamma}). They summarize the results of the E760 (updated) and E835 measurements of mass, width and B({chi}{sub cJ} {yields} {bar p}p){Lambda}({chi}{sub cJ} {yields} J/{psi} + {gamma}) (J = 0,1,2) and discuss the significance of these measurements.
Date: March 1, 2005
Creator: Andreotti, M.; Bagnasco, S.; Baldini, W.; Bettoni, D.; Borreani, G.; Buzzo, A. et al.
System: The UNT Digital Library
US accelerator contribution to the LHC (open access)

US accelerator contribution to the LHC

In 1998, the United States entered into an agreement with CERN to help build the Large Hadron Collider (LHC), with contributions to the accelerator and to the large HEP detectors. To accomplish this, the US LHC Accelerator Project was formed, encompassing expertise from Brookhaven National Laboratory (BNL), Fermi National Accelerator Laboratory (FNAL) and the Lawrence Berkeley National Laboratory (LBNL). This report is a summary of these contributions including the progress towards project completion, as well as a discussion of future plans for continued US participation in the LHC accelerator.
Date: May 1, 2005
Creator: Lamm, Michael J.
System: The UNT Digital Library
Comparing Statewide Economic Impacts of New Generation from Wind, Coal, and Natural Gas in Arizona, Colorado, and Michigan: Preprint (open access)

Comparing Statewide Economic Impacts of New Generation from Wind, Coal, and Natural Gas in Arizona, Colorado, and Michigan: Preprint

With increasing concerns about energy independence, job outsourcing, and risks of global climate change, it is important for policy makers to understand all impacts from their decisions about energy resources. This paper assesses one aspect of the impacts: direct economic effects. The paper compares impacts to states from equivalent new electrical generation from wind, natural gas, and coal. Economic impacts include materials and labor for construction, operations, maintenance, fuel extraction, and fuel transport, as well as project financing, property tax, and landowner revenues. We examine spending on plant construction during construction years, in addition to all other operational expenditures over a 20-year span. Initial results indicate that adding new wind power can be more economically effective than adding new gas or coal power, and that a higher percentage of dollars spent on coal and gas will leave the state. For this report, we interviewed industry representatives and energy experts, in addition to consulting government documents, models, and existing literature. The methodology for this research can be adapted to other contexts for determining economic effects of new power generation in other states and regions.
Date: August 1, 2005
Creator: Tegen, S.
System: The UNT Digital Library
Field quality study in Nb(3)Sn accelerator magnets (open access)

Field quality study in Nb(3)Sn accelerator magnets

Four nearly identical Nb{sub 3}Sn dipole models of the same design were built and tested at Fermilab. It provided a unique opportunity of systematic study the field quality effects in Nb{sub 3}Sn accelerator magnets. The results of these studies are reported in the paper.
Date: May 1, 2005
Creator: Kashikhin, V. V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; DiMarco, J. et al.
System: The UNT Digital Library
K0(s) and Lambda0 production studies in p anti-p collisions at s**(1/2) = 1800 and 630-GeV (open access)

K0(s) and Lambda0 production studies in p anti-p collisions at s**(1/2) = 1800 and 630-GeV

The authors present a study of the production of K{sub s}{sup 0} and {Lambda}{sup 0} in inelastic p{bar p} collisions at {radical}s = 1800 and 630 GeV using data collected by the CDF experiment at the Fermilab Tevatron. Analyses of K{sub s}{sup 0} and {Lambda}{sup 0} multiplicity and transverse momentum distributions, as well as of the dependencies of the average number and (p{sub T}) of K{sub s}{sup 0} and {Lambda}{sup 0} on charged particle multiplicity are reported. Systematic comparisons are performed for the full sample of inelastic collisions, and for the low and high momentum transfer subsamples, at the two energies. The p{sub T} distributions extend above 8 GeV/c, showing a (p{sub T}) higher than previous measurements. The dependence of the mean K{sub s}{sup 0}({Lambda}{sup 0}) p{sub T} on the charged particle multiplicity for the three samples shows a behavior analogous to that of charged primary tracks.
Date: April 1, 2005
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
System: The UNT Digital Library
A Search for supersymmetric Higgs bosons in the di-tau decay mode in p anti-p collisions at s**(1/2) = 1.8-TeV (open access)

A Search for supersymmetric Higgs bosons in the di-tau decay mode in p anti-p collisions at s**(1/2) = 1.8-TeV

A search for direct production of Higgs bosons in the di-tau decay mode is performed with 86.3 {+-} 3.5 pb{sup -1} of data collected with the Collider Detector at Fermilab during the 1994-1995 data taking period of the Tevatron. We search for events where one tau decays to an electron plus neutrinos and the other tau decays hadronically. We perform a counting experiment and set limits on the cross section for supersymmetric Higgs boson production where tan {beta} is large and m{sub A} is small. For a benchmark parameter space point where m{sub A{sup 0}} = 100 GeV/c{sup 2} and tan {beta} = 50, we limit the production cross section multiplied by the branching ratio to be less than 77.9 pb at the 95% confidence level compared to theoretically predicted value of 11.0 pb. This is the first search for Higgs bosons decaying to tau pairs at a hadron collider.
Date: June 1, 2005
Creator: Acosta, D.; Affolder, Anthony A.; Albrow, M. G.; Ambrose, D.; Amidei, D.; Anikeev, K. et al.
System: The UNT Digital Library
Impact of a new Cerenkov light parameterisation on the reconstruction of shower profiles from Auger hybrid data (open access)

Impact of a new Cerenkov light parameterisation on the reconstruction of shower profiles from Auger hybrid data

The light signal measured by fluorescence telescopes receives--strongly depending on the shower geometry with respect to the detector--a non-negligible contribution from additionally produced Cherenkov light. This Cherenkov contribution has to be accounted for to determine primary parameters properly. In comparison to the previous ansatz used by other experiments, the impact of a new analytical description of Cherenkov light production in EAS on the Auger event reconstruction is investigated.
Date: July 1, 2005
Creator: Nerling, Frank; /Karlsruhe, Forschungszentrum; Bluemer, J.; /Karlsruhe, Forschungszentrum /Karlsruhe U.; Engel, R.; Unger, M. et al.
System: The UNT Digital Library
The performance of the corrector lenses for the Auger fluorescence detector (open access)

The performance of the corrector lenses for the Auger fluorescence detector

We present an analysis of the effect that the corrector lenses (Schmidt Optics) have on the overall performance of the Auger Fluorescence Detector. The analysis uses real data from the telescopes. Figures of merit for the corrector lenses performance include shower trigger rate and the distribution of the distance of closest approach to the shower axis. As a result of this analysis we may say that the effective light collection area of a telescope nearly doubles with the use of a corrector lens at its aperture.
Date: July 1, 2005
Creator: Sato, Ricardo; Escobar, Carlos O. & U., /Campinas State
System: The UNT Digital Library
The MiniBooNE primary beamline (open access)

The MiniBooNE primary beamline

None
Date: July 1, 2005
Creator: Kobilarcik, Thomas R.
System: The UNT Digital Library
Unveiling neutrino mixing and leptonic CP violation (open access)

Unveiling neutrino mixing and leptonic CP violation

We review the present understanding of neutrino masses and mixings, discussing what are the unknowns in the three family oscillation scenario. Despite the anticipated success coming from the planned long baseline neutrino experiments in unraveling the leptonic mixing sector, there are two important unknowns which may remain obscure: the mixing angle {theta}{sub 13} and the CP-phase {delta}. The measurement of these two parameters has led us to consider the combination of superbeams and neutrino factories as the key to unveil the neutrino oscillation picture.
Date: January 1, 2005
Creator: Mena, Olga
System: The UNT Digital Library
NuTeV structure function measurement (open access)

NuTeV structure function measurement

The NuTeV experiment obtained high statistics samples of neutrino and antineutrino charged current events during the 1996-1997 Fermilab fixed target run. The experiment combines sign-selected neutrino and antineutrino beams and the upgraded CCFR iron-scintillator neutrino detector. A precision continuous calibration beam was used to determine the muon and hadron energy scales to a precision of 0.7% and 0.43% respectively. The structure functions F{sub 2}(x, Q{sup 2}) and xF{sub 3}(x, Q{sup 2}) obtained by fitting the y-dependence of the sum and the difference of the {nu} and {bar {nu}} differential cross sections are presented.
Date: July 1, 2005
Creator: Tzanov, M. & U., /Pittsburgh
System: The UNT Digital Library
A Photometric redshift galaxy catalog from the Red-Sequence Cluster Survey (open access)

A Photometric redshift galaxy catalog from the Red-Sequence Cluster Survey

The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the z' and R{sub c} bands for 90 square degrees of sky, and supplemental V and B data have been obtained for 33.6 deg{sup 2}. They compile a photometric redshift catalog from these 4-band data by utilizing the empirical quadratic polynomial photometric redshift fitting technique in combination with CNOC2 and GOODS/HDF-N redshift data. The training set includes 4924 spectral redshifts. The resulting catalog contains more than one million galaxies with photometric redshifts < 1.5 and R{sub c} < 24, giving an rms scatter {delta}({Delta}z) < 0.06 within the redshift range 0.2 < z < 0.5 and {sigma}({Delta}z) < 0.11 for galaxies at 0.0 < z < 1.5. They describe the empirical quadratic polynomial photometric redshift fitting technique which they use to determine the relation between red-shift and photometry. A kd-tree algorithm is used to divide up the sample to improve the accuracy of the catalog. They also present a method for estimating the photometric redshift error for individual galaxies. They show that the redshift distribution of the sample is in excellent agreement with smaller and much deeper photometric and spectroscopic redshift surveys.
Date: February 1, 2005
Creator: Hsieh, Bau-Ching; Yee, H. K. C.; Lin, H. & Gladders, M. D.
System: The UNT Digital Library
Background reduction in cryogenic detectors (open access)

Background reduction in cryogenic detectors

This paper discusses the background reduction and rejection strategy of the Cryogenic Dark Matter Search (CDMS) experiment. Recent measurements of background levels from CDMS II at Soudan are presented, along with estimates for future improvements in sensitivity expected for a proposed SuperCDMS experiment at SNOLAB.
Date: April 1, 2005
Creator: Bauer, Daniel A.
System: The UNT Digital Library
Bounds on the neutrino mixing angles and CP phase for an SO(10) model with lopsided mass matrices (open access)

Bounds on the neutrino mixing angles and CP phase for an SO(10) model with lopsided mass matrices

None
Date: February 1, 2005
Creator: Albright, Carl H. & /Fermilab, /Northern Illinois U.
System: The UNT Digital Library
Modeling the Market Potential of Hydrogen from Wind and Competing Sources (open access)

Modeling the Market Potential of Hydrogen from Wind and Competing Sources

Developed from the Wind Deployment Systems (WinDS) model, the Hydrogen Deployment Systems (HyDS) model is a computer model of U.S. market expansion of hydrogen production from wind and other sources over the next 50 years. The WinDS model was developed in 2003 to model the expansion of generation and transmission capacity in the U.S. electric sector spanning the next 50 years. It minimizes system-wide costs of meeting loads, reserve requirements, and emission constraints by building and operating new generators and transmission in 26 two-year periods from 2000 to 2050. While it includes all major types of conventional generators, the WinDS model focuses on addressing the market issues of greatest significance to wind-specifically issues of electricity transmission and intermittency.
Date: May 1, 2005
Creator: Short, Walter; Blair, Nate & Heimiller, Donna
System: The UNT Digital Library
Cost Analysis of a Concentrator Photovoltaic Hydrogen Production System (open access)

Cost Analysis of a Concentrator Photovoltaic Hydrogen Production System

The development of efficient, renewable methods of producing hydrogen are essential for the success of the hydrogen economy. Since the feedstock for electrolysis is water, there are no harmful pollutants emitted during the use of the fuel. Furthermore, it has become evident that concentrator photovoltaic (CPV) systems have a number of unique attributes that could shortcut the development process, and increase the efficiency of hydrogen production to a point where economics will then drive the commercial development to mass scale.
Date: August 1, 2005
Creator: Thompson, Jamal R.; McConnell, Robert D. & Mosleh, Mohsen
System: The UNT Digital Library
EXPLORING THE QUARK GLUON PLASMA WITH BIKASH SINHA. (open access)

EXPLORING THE QUARK GLUON PLASMA WITH BIKASH SINHA.

This paper presents a personal account of the scientific and professional adventures of Bikash Sinha on the occasion of the celebration of his 60th birthday held in Calcutta on Feb 7, 2005.
Date: February 1, 2005
Creator: McLerran, L.
System: The UNT Digital Library
XPS and UPS Investigation of NH4OH-Exposed Cu(In,Ga)Se2 Thin Films (open access)

XPS and UPS Investigation of NH4OH-Exposed Cu(In,Ga)Se2 Thin Films

Photoelectron spectroscopy was used to determine the compositional and electronic changes occurring in Cu(In,Ga)Se2 thin films as a result of immersion in aqueous ammonia solution. We find that NH4OH-treated CIGS surfaces are preferentially etched of indium and gallium, resulting in the formation of a thin layer of a degenerate Cu-Se compound that we tentatively identify as Cu2Se. The work function of ammonia-treated samples is found to increase by 0.6 eV relative to as-grown CIGS thin films. The uniformity of chemical bath effects (etching & deposition) was found to be improved by the addition to the bath of a non-ionic surfactant. Initial device results show that the new surfactant-based chemical bath deposition (CBD) method may lead to better and thinner CdS buffer layers.
Date: February 1, 2005
Creator: Perkins, C. L.; Hasoon, F. S.; Al-Thani, H. A.; Asher, S. E. & Sheldon, P.
System: The UNT Digital Library
Deterioration of the skew quadrupole moment in Tevatron dipoles over time (open access)

Deterioration of the skew quadrupole moment in Tevatron dipoles over time

During the 20 years since it was first commissioned, the Fermilab Tevatron has developed strong coupling between the two transverse degrees of freedom. A circuit of skew quadrupole magnets is used to correct for coupling and, though capable, its required strength has increased since 1983 by more than an order of magnitude. In more recent years changes to the Tevatron for colliding beams operation have altered the skew quadrupole corrector distribution and strong local coupling become evident, often encumbering routine operation during the present physics run. Detailed magnet measurements were performed on each individual magnet during construction, and in early 2003 it was realized that measurements could be performed on the magnets in situ which could determine coil movements within the iron yoke since the early 1980's. It was discovered that the superconducting coils had become vertically displaced relative to their yokes since their construction. The ensuing systematic skew quadrupole field introduced by this displacement accounts for the required corrector settings and observed beam behavior. An historical account of the events leading to this discovery and progress toward its remedy are presented.
Date: May 1, 2005
Creator: Syphers, M. J. & Harding, D. J.
System: The UNT Digital Library
Detection of very inclined showers with the Auger Observatory (open access)

Detection of very inclined showers with the Auger Observatory

The Pierre Auger Observatory can detect air showers with high efficiency at large zenith angles with both the fluorescence and surface detectors. Since half the available solid angle corresponds to zeniths between 60 and 90 degrees, a large number of inclined events can be expected and are indeed observed. In this paper, we characterize the inclined air showers detected by the Observatory and we present the aperture for inclined showers and an outlook of the results that can be obtained in future studies of the inclined data set.
Date: July 1, 2005
Creator: Nellen, Lukas & /Mexico U., ICN
System: The UNT Digital Library
Towards a Wind Energy Climatology at Advanced Turbine Hub-Heights: Preprint (open access)

Towards a Wind Energy Climatology at Advanced Turbine Hub-Heights: Preprint

Measurements of wind characteristics over a wide range of heights up to and above 100 m are useful to: (1) characterize the local and regional wind climate; (2) validate wind resource estimates derived from numerical models; and (3) evaluate changes in wind characteristics and wind shear over the area swept by the blades. Developing wind climatology at advanced turbine hub heights for the United States benefits wind energy development. Tall tower data from Kansas, Indiana, and Minnesota (which have the greatest number of tall towers with measurement data) will be the focus of this paper. Analyses of data from the tall towers will start the process of developing a comprehensive climatology.
Date: May 1, 2005
Creator: Schwartz, M. & Elliott, D.
System: The UNT Digital Library
Beauty production cross section measurements at E(cm) = 1.96-TeV (open access)

Beauty production cross section measurements at E(cm) = 1.96-TeV

The RunII physics program at the Tevatron started in spring 2001 with protons and antiprotons colliding at an energy of {radical}s = 1.96 TeV, and it is carrying on with more than 500 pb{sup -1} of data as collected by both the CDF and D0 experiments. Recent results on beauty production cross section measurements are here reported.
Date: May 1, 2005
Creator: D'Onofrio, Monica & U., /Geneva
System: The UNT Digital Library