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in subjects: "Mass Spectra"

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Speciation of chromium and manganese using pneumatically assisted electrospray mass spectrometry

It is not an exaggeration to say that much of chemistry involves ions in solution. A technique which allows for ions to be transferred from solution into the gas phase and subsequently analyzed by mass spectrometric detection would be of importance. If structural information, representative of the solution chemistry could be gained from these gas-phase ions, this would also be important. Electrospray mass spectrometry (ES-MS) is such a technique.

Date: February 1, 1997

Creator: Gwizdala, A.B. III

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

The dijet mass spectrum at D-Zero

We present preliminary results from an analysis of jet data collected during the 1994-95 Tevatron Collider run with an integrated luminosity of 93 pb{sup -1}. Measurements of dijet mass spectra in {anti p}p collisions at {radical}s = 1.8 TeV are compared to next-to-leading order QCD calculations.

Date: November 1, 1997

Creator: Abbott, B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Characterization of asphaltenes from processed resids

The current and future trend for petroleum processing is towards conversion of heavier and heavier fractions into useful products such as gasoline and diesel. Asphaltenes, the heptane insoluble fraction of heavy oils, are a solubility class and not a specific boiling range. They tend to be the hardest fraction to process in the refinery because of their high molecular mass, aromaticity and heteroatom and metal (S, N, Ni, V) content. Molecular characterization of asphaltenes is important since a… more

Date: April 1, 1997

Creator: Hunt, J. E.; Winans, R. E. & Miller, J. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Excited charmed mesons

The experimental status of excited charmed mesons is reviewed and is compared to theoretical expectations. Six states have been observed and their properties are consistent with those predicted for excited charmed states with orbital angular momentum equal to one.

Date: May 1, 1995

Creator: Butler, J.N. & Shukla, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Masses of orbitally excited baryons in large N{sub c} QCD

The authors present the first phenomenological study of the masses of orbitally excited baryons in large N{sub c} QCD. Restricting here to the nonstrange sector of the L=1 baryons, the 1/N{sub c} expansion is used to order and select a basis of effective operators that spans the nine observables (seven masses and two mixing angles). Fits are performed using subsets of the complete set of nine operators, including corrections up to O(1/N{sub c}) where leading order is N{sub c}{sup 1}. This study… more

Date: July 1, 1998

Creator: Carlson, Carl E.; Carone, Christopher D.; Goity, Jose' L. & Lebed, Richard F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Laser ablation of silicate glasses doped with transuranic actinides

Direct sampling laser ablation plasma mass spectrometry (DS-LAMS) was applied to silica glasses doped with {sup 237}Np, {sup 242}Pu or {sup 241}Am using a unique instrument recently installed into a transuranic glovebox. The primary goal was to assess the utility of mass spectrometry of directly ablated ions for facile evaluation of actinide (An) constituents of silicate glass immobilization matrices used for encapsulation of radionuclides. The instrument and general procedures have been descri… more

Date: October 1, 1998

Creator: Gibson, J. K. & Haire, R. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

CDF results on Z{gamma} production

Results on Z{sub {gamma}} production observed by the Collider Detector at Fermilab (CDF) from the Tevatron Collider Run lb and preliminary results from 36pb{sup {minus}1} of integrated luminosity from Run lb. Both the Run la and lb results are consistent with expectations from the Standard Model.

Date: April 1, 1995

Creator: Wagner, R. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The dijet mass cross section at the Tevatron

We present recent results on dijet production in p{anti p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. Data from both CDF and D0 experiments are shown. Dijet measurements complement prior inclusive jet measurements, which have shown a possible excess above expectations at high transverse energy. The same trend is seen in the dijet mass spectra.

Date: May 11, 1999

Creator: Hauser, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The nature and fate of natural resins in the geosphere VI. Analysis of fossil resins from Axel Heiberg Island Canadian Arctic

Ambers are well known and abundant in terrestrial sediments all over the world; however, due largely to the absence of definite morphological characteristics, the precise botanical origin of most amber samples, are at best, often a matter of speculation. This has severely restricted the usefulness of amber in paleobotanical and paleoecological interpretations. The molecular composition and structural characteristics of fossil resins however, may preserve evidence of their botanical origin, whic… more

Date: June 1, 1995

Creator: Anderson, K.B. & LePage, B.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Single top production and M{subscriptT Tbar}

Single top production provides opportunities for studying the charged-current weak interaction of the top quark. The t{anti t} invariant mass spectrum M{sub t{anti t}} enables the search for non-standard model t{anti t} resonance states. These two topics have motivated new developments in top quark related analyses at Fermilab Tevatron. This presenta- tion reports the current single top and M{sub t{anti t}} analysis methods and the corresponding results from the collider Run I data collected by… more

Date: May 11, 1999

Creator: Liu, Yi-Cheng

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The Parity Partner of the Nucleon in Quenched QCD With Domain Wall Fermions

The authors present preliminary results for the mass spectrum of the nucleon and its low-lying excited states from quenched lattice QCD using the domain wall fermion method which preserves the chiral symmetry at finite lattice cutoff. Definite mass splitting is observed between the nucleon and its parity partner. This splitting grows with decreasing valence quark mass. They also present preliminary data regarding the first positive-parity excited state.

Date: July 12, 2000

Creator: Sasaki, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Spectroscopy and lifetime of bottom and charm hadrons

There are several motivations for studying masses and lifetimes of the hadrons containing a heavy quark, either the bottom or the charm quark. First, the mass and the lifetime are fundamental properties of an elementary particle. Second, the spectroscopy of hadrons gives insights into the QCD potential between quarks. In particular, a symmetry exists for heavy hadrons when the heavy quark mass is taken to be infinite, providing a powerful tool to predict and understand properties of those heavy… more

Date: May 15, 2000

Creator: Ukegawa, F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Development of silicon drift detectors for strangeness measurements

Detection of multi-strange and charm particles requires precise measurements of the secondary vertices close to the interaction point and the decay products of strange and charm particles. This presents an unprecedented challenge for relativistic heavy ion experiments, where multiplicity reaches thousands of final state particles per collision. Development of affordable technology for realizing high spatial resolution and low mass vertex detectors has become the ultimate goal of many R&D projec… more

Date: February 1, 1995

Creator: Odyniec, G.; Krieger, B.; Krofcheck, D.; Lewak, D.; O`Donnel, R.; Partlan, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Strange particle measurements from the EOS TPC

A high statistics sample of {Lambda}`s produced in 2 GeV/nucleon {sup 5}8Ni + {sup nat}Cu collisions has been obtained with the EOS Time Projection Chamber at the Bevalac. The coverage of the EOS TPC is essentially 100% for y > y{sub cm} and extends down to P{sub T} = 0 where interesting effects such as collective radial expansion may be important. In addition, the detection of a majority of the charged particles in the TPC, along with the presence of directed flow for protons and heavier fragm… more

Date: February 1, 1995

Creator: Justice, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

On {vert_bar}V{sub ub}{vert_bar} from the Bbar {r_arrow} Xul nu bar dilepton invariant mass spectrum

No Description Available.

Date: November 29, 2000

Creator: Bauer, Christian W & Luke, Zoltan Ligeti and Michael

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Relativistic statistical mechanics and particle spectroscopy

The author reviews the formulation of manifestly covariant relativistic statistical mechanics as the description of an ensemble of events in spacetime parameterized by an invariant proper time {tau}. He discusses the linear and cubic mass spectra which result from this formulation (the latter with the inclusion of anti-events) as the actual spectra of an individual hadronic multiplet and hot hadronic matter, respectively. These spectra allow one to predict the masses of particles nucleated to q… more

Date: December 1998

Creator: Burakovsky, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Are partons confined tachyons?

The author notes that if hadrons are gravitationally stabilized ``black holes``, as discrete physics suggests, it is possible that partons, and in particular quarks, could be modeled as tachyons, i.e. particles having v{sup 2} > c{sup 2}, without conflict with the observational fact that neither quarks nor tachyons have appeared as ``free particles``. Some consequences of this model are explored.

Date: March 1, 1996

Creator: Noyes, H. Pierre

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Search for exotic particles at CDF

CDF has searched for 2nd generation leptoquarks, new gauge bosons W{prime} and Z{prime}, axigluons, excited quarks, color octet technirhos and E{sub 6} diquarks. We place the most stringent limits on direct production of these exotic particles.

Date: February 1, 1995

Creator: Harris, R.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Directed flow and particle production in Au+Au collisions from experiment E877 at the AGS

In this article we summarize recent results on the study of Au+Au collisions at 10.8A GeV/c obtained at the AGS by the E877 Collaboration. New results on the directed sideward flow are presented. In particular, the dependence of proton and pion production on the direction of the reaction plane will be discussed. It is shown that the sideward flow is mainly due to nucleons and that pions show little flow effects. Two-pion correlation functions are studied to derive the density at freeze-out. Fur… more

Date: May 1, 1996

Creator: Barrette, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Search for direct photon production in 200 A GeV S + Au reactions: A status report

Direct thermal photons in the PT range of 0 - 5 GeV/c are expected to provide a sensitive probe of the hot dense matter formed in the early stage of relativistic heavy ion collisions. The production of single photons in 200 A GeV S+Au reactions has been investigated using the 3800 element Pbglass calorimeter of CERN experiment WA80. Neutral {pi}{sup o} and {eta} cross sections have been measured via their two-photon decay branch yields. In a first analysis of the WA80 results, a slight excess p… more

Date: December 31, 1995

Creator: Awes, T.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Report on 1992/1993 activities

Over the past several years, at least four different techniques have been developed for probing the behavior of homopolymers and block copolymers at surfaces and interfaces. These include neutron reflectivity, grazing incidence x-ray scattering, dynamic secondan, ion mass spectrometry and electron microscopy. In the upcoming year It is proposed to make key uses of these developments to gain a quantitative understanding of the Interfacial behavior of homopolymers and block copolymers. In additio… more

Date: July 1, 1996

Creator: Russell, T. P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The dijet mass spectrum and angular distributions with the D0 detector

We present preliminary results from an analysis of dijet data collected during the 1994-95 Tevatron Collider run with an integrated luminosity of 91 pb{sup -1}. Measurements of dijet mass spectra and dijet angular distributions in {anti p}p collisions at {radical}s- = 1.8 TeV are compared with next-to-leading order QCD theory.

Date: July 1, 1996

Creator: Abachi, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The experimental investigation of supersymmetry breaking

If Nature is supersymmetric at the weak interaction scale, what can we hope to learn from experiments on supersymmetric particles? The most mysterious aspect of phenomenological supersymmetry is the mechanism of spontaneous supersymmetry breaking. This mechanism ties the observable pattern of supersymmetric particle masses to aspects of the underlying unified theory at very small distance scales. In this article, I will discuss a systematic experimental program to determine the mechanism of sup… more

Date: April 1, 1996

Creator: Peskin, M.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Electroweak results from the Tevatron

Results from the CDF and D{O} experiments are presented on properties of the W{plus_minus} and Z{sup 0} gauge bosons using final states containing electrons and muons based on large integrated luminosities. In particular, measurements of the W{plus_minus} and Z{sup 0} production cross sections, the W-charge asymmetry and the CDF measurement of the W-mass are summarized. Gauge boson self interactions axe measured by studying di-gauge boson production and limits on anomalous gauge boson couplings… more

Date: October 1, 1995

Creator: Demarteau, M.

Item Type: Report

Partner: UNT Libraries Government Documents Department