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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Stochastic implementation of improved actions for gauge theories on a lattice

Unknown Date (has links)
We investigate the use of a random or stochastic process to perform Monte Carlo simulations of improved actions for pure SU(2) gauge theory formulated on a lattice. The improved actions studied are extensions of Wilson's simple plaquette action to include six-link plaquettes. The stochastic or "noisy" method involves computing additional terms in the action such that they have the correct values on the average. We devise two schemes for achieving this and compare them to the Metropolis method, where the additional terms are computed exactly. We find that the noisy methods produce independent configurations more rapidly than the Metropolis method. The greatest improvement is found to be by roughly a factor of two. The results, however, are sensitive to the values of the coefficients of the additional terms in the action. Our study indicates that for more complex actions a noisy method will be significantly superior to an exact method such as the Metropolis algorithm. This means that current lattice sizes and computer resources can be used to measure observables much closer to the continuum limit. / Source: Dissertation Abstracts International, Volume: 50-03, Section: B, page: 0998. / Major Professor: Joseph F. Owens. / Thesis (Ph.D.)--The Florida State University, 1989.
22

The atomic weight dependence and mass cross-sections of massive hadron pair production in proton-nucleus collisions at 800 GeV/c

Unknown Date (has links)
The production of massive hadron pairs has been studied in the reaction $p + N \to h\sb1 + h\sb2 + X$ using a proton beam at 800 GeV/c and four nuclear targets: beryllium, aluminum, iron, and tungsten. The data were taken at the Fermi National Accelerator Laboratory from November 1987-February 1988. / The detector was a double arm magnetic spectrometer, with a sampling calorimeter for real-time event selection. It was capable of operating at a high interaction rate ($\approx$2.5 $\times$ 10$\sp6$ interactions per second) and accepted +$-$, ++, and $--$ hadron pair charge states. / The mass dependence of the differential cross section for hadron pair production was determined over a mass range, 6.0 GeV/c$\sp2 \leq M \leq 15.0$ GeV/c$\sp2$, for the four targets and three charge states and was shown to agree well with QCD calculations. / The dependence of the cross section on the atomic weight of the target was shown to be accurately described by the form $\sigma(A) \propto A\sp\alpha$. The values of $\alpha$ were determined as a function of mass and charge state and were found to have an average value $\alpha$ = 1.043 $\pm$ 0.011(stat.) $\pm$ 0.025(syst.) when the transverse momentum of the pair, $P\sb{T}$, was $\leq$1.0 GeV/c and $\alpha$ = 1.049 $\pm$ 0.007(stat.) $\pm$ 0.025(syst.) for $P\sb{T} \leq 2.0$ GeV/c. No significant variation over the range of mass or charge state was observed. The values of $\alpha$ determined by this experiment agree well with previously published results of $\alpha$ for unlike-sign charged hadron pairs and are consistent with the parton multiple scattering model of atomic weight dependence. We have extended the knowledge of the atomic weight dependence of hadron pair production to measurements of $\alpha$ for different charge states, a higher mass region, and with better statistical accuracy. / Source: Dissertation Abstracts International, Volume: 50-03, Section: B, page: 1000. / Major Professor: David A. Levinthal. / Thesis (Ph.D.)--The Florida State University, 1989.
23

Calculation of the mass spectrum and deconfining temperature in non-Abelian gauge theory

Unknown Date (has links)
Using a small volume expansion the mass spectrum and deconfining temperature of SU(2) and SU(3) gauge theory are evaluated. Including non-perturbative features by restoring symmetries which were broken in perturbation theory we obtain results which are valid up to intermediate volumes. The mass spectrum obtained is in good agreement with Luscher's small volume expansion in the small-volume limit and with Monte Carlo Data in medium sized volumes. Using asymmetric volumes we are able to derive the deconfining temperature and find a reasonable agreement with Monte Carlo calculations. / Source: Dissertation Abstracts International, Volume: 51-01, Section: B, page: 0257. / Major Professor: Bernd A. Berg. / Thesis (Ph.D.)--The Florida State University, 1989.
24

Search for supersymmetry at the CERN large hadron collider

Unknown Date (has links)
Supersymmetry (SUSY) has been known as a beautiful solution to the fine tuning problem of the Standard Model but so far there is no direct experimental evidence of its existence. However, the coming decade could be the decade of SUSY due to the ongoing project of the CERN Large Hadron Collider (LHC). Several SUSY signals for the LHC have been studied; the potential for a thorough SUSY search has been demonstrated. By looking at multi-jet plus $E\sb{T}$ events, $m\sb{\tilde g} \sim$ 1300 (2000) GeV can be explored if $m\sb{\tilde q} \gg m\sb{\tilde g}$ $(m\sb{\tilde q} \simeq m\sb{\tilde g});$ jet multiplicity will yield information on whether squark production makes a significant contribution; reconstructing hemisphere masses may yield a measure of $m\sb{\tilde g}$ to 15-25%. For the trilepton signal, a set of cuts was developed to isolate $\tilde\chi\sbsp{1}{\pm}\tilde\chi\sbsp{2}{0}$ events; as long as the spoiler modes (i.e. $\tilde\chi\sbsp{2}{0} \to \tilde\chi\sbsp{1}{0}Z$ and $\tilde\chi\sbsp{2}{0}$ $\to \tilde\chi\sbsp{1}{0}H\sb\ell$) are not open and the $\tilde\chi\sbsp{2}{0}\to\tilde\chi\sbsp{1}{0}\ell\bar\ell$ interference effect is not severe, most of the parameter space can be probed. A precise measurement of $m\sb{\tilde\chi\sbsp{2}{0}} \ - m\sb{\tilde\chi\sbsp{1}{0}}$ can be made. For the dilepton signal from slepton production, $m\sb{\tilde\ell\sb{R}} \sbsp{\sim}{<}$ 200-275 GeV ought to be explorable. Physics at the unification scale ($\sim$10$\sp{16}$ GeV) described in the supergravity (SUGRA) model can also be tested at the LHC. / Source: Dissertation Abstracts International, Volume: 56-08, Section: B, page: 4381. / Major Professor: Howard A. Baer. / Thesis (Ph.D.)--The Florida State University, 1995.
25

Search for squarks and gluinos with the D-zero detector

Unknown Date (has links)
A search for the pair production of supersymmetric particles using data from the DO detector at the Fermilab pp Tevatron collider, with center of mass energy $\sqrt{s}$ = 1.8 TeV, has yielded a null result. The search was performed looking for gluino and squark decays with a signature of multiple particle jets and high missing transverse energy. With a total luminosity of 7.5 pb$\sp{-1}$ of data, and with no signal events observed above expected Standard Model backgrounds, the existence of gluinos and squarks has been excluded with masses below 213 GeV/c$\sp2$ at the 95% confidence level for equal squark and gluino mass. / Source: Dissertation Abstracts International, Volume: 56-08, Section: B, page: 4382. / Major Professor: Horst Wahl. / Thesis (Ph.D.)--The Florida State University, 1995.
26

FOUR CHARGED PARTICLE FINAL STATES FROM THE REACTION POSITIVE PION-DEUTERON AT 15 GEV/C

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 36-01, Section: B, page: 0293. / Thesis (Ph.D.)--The Florida State University, 1975.
27

A STUDY OF THE REACTION NEGATIVE KAON-NEUTRON ---> NEGATIVE PION, NEGATIVE PION, POSITIVE SIGMA-HYPERON USING A NEWLY DEVELOPED ISOBAR MODEL WITH UNITARITY

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 37-01, Section: B, page: 0293. / Thesis (Ph.D.)--The Florida State University, 1975.
28

A PARTIAL WAVE ANALYSIS OF THE REACTION NEGATIVE KAON-NEUTRON ---> NEUTRAL LAMBDA-HYPERON, NEGATIVE PION, NEUTRAL PION FROM 1610 TO 1710 MEV

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 37-12, Section: B, page: 6190. / Thesis (Ph.D.)--The Florida State University, 1976.
29

STRANGE PARTICLE FINAL STATES FROM 15 GEV/C POSITIVE PION-DEUTERON INTERACTIONS

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 36-06, Section: B, page: 2885. / Thesis (Ph.D.)--The Florida State University, 1975.
30

A DECK MODEL ANALYSIS OF THE REACTION POSITIVE PION-DEUTERON ---> POSITIVE PION, POSITIVE PION, NEGATIVE PION, DEUTERON AT 15 GEV/C

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 37-07, Section: B, page: 3481. / Thesis (Ph.D.)--The Florida State University, 1976.

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