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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.
11

OBSERVATION OF DOUBLE PHI MESON PRODUCTION IN 400 GEV/C PROTON-NUCLEON INTERACTIONS

Unknown Date (has links)
The production of pairs of (phi) mesons has been observed in 400 GeV/c proton-nucleon interactions at the Fermilab Multiparticle Spectrometer in the inclusive reaction p N (--->) (phi)(phi) + X, where each (phi) decays to a K+K-pair. / A fast (200ns), high-level trigger processor was used on-line to selectively trigger on events containing two pairs of oppositely charged kaons having low invariant masses. The experimental apparatus and trigger processor are described. / From a sample of 120,000 reconstructed events having at least 2 K+ and 2 K- tracks in the momentum range 5.8 (LESSTHEQ) p (LESSTHEQ) 23.0 GeV/c, the K+K-K+K-, (phi)K+K- and (phi)(phi) invariant mass spectra are presented. A total of 1503 events are identified as being consistent with (phi)(phi) production. / After background subtraction and acceptance corrections, the total cross sections per nucleon for (phi)(phi) and (phi)K+K- production at 400 GeV/c are found to be (sigma)(,T)(pN(--->)(phi)(phi)+X) = 0.87 (+OR-) 0.27 (mu)b and (sigma)(,T)(pN(--->)(phi)K+K-+X) = 23.6 (+OR-) 2.7 (mu)b. An upper limit on the cross section times branching ratio for (eta)(,c) production at 400 GeV/c is established to be (sigma)(,T)(pN(--->)(eta)(,c)+X)(.)BR((eta)(,c)(--->)(phi)(phi)) (LESSTHEQ) 30 nb. / Source: Dissertation Abstracts International, Volume: 46-01, Section: B, page: 0204. / Thesis (Ph.D.)--The Florida State University, 1984.
12

D(1285) AND E(1420) MESON PRODUCTION IN ANTIPROTON-PROTON ---> (POSITIVE KAON, KAON(SHORT-LIVED), NEGATIVE PION)X AT 6.6 GEV/C (SPECTROSCOPY)

Unknown Date (has links)
We have observed the D(1285) and E(1420) mesons in the interaction pp (--->) (K('+)K(,s)(pi)('-))X with a p beam at 6.6 GeV/c. The data were taken at the Brookhaven National Laboratory Multiparticle Spectrometer facility in the spring of 1983. We have 420 D events and 620 E events in a sample of 11,686 total events. We have fitted the K('+)K(,s)(pi)('-) mass spectrum, corrected for acceptance, with two Breit-Wigner functions and background. We have performed a Dalitz plot/Zemach analysis using intermediate decay modes (delta)(pi) and K('*)K and spin-parity/G-parity J('PG) 0('-+), 0('--), 1('++), 1('+-), 1('-+), 1('--). We find the D to have mass (1.277 (+OR-) .002) GeV and width (32 (+OR-) 8) MeV and to be consistent with J('PG) = 1('++), decay mode (delta)(pi). We find the E to have mass (1.424 (+OR-) .003) GeV and width (60 (+OR-) 10) MeV, with J('PG) = 1('++) and decay mode predominantly (delta)(pi), with some K('*)K present. We find a large non-resonant 1('++) K('*)K background in the E region. The results of the E analysis compare well with those from the (pi)('-)p (--->) (K('+)K(,s)(pi)('-))n experiment performed at the same facility by the same collaboration. / Source: Dissertation Abstracts International, Volume: 46-09, Section: B, page: 3096. / Thesis (Ph.D.)--The Florida State University, 1985.
13

ON THE UNIQUENESS OF INTERACTIONS INVOLVING HIGHER SPIN PARTICLES

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 32-09, Section: B, page: 5370. / Thesis (Ph.D.)--The Florida State University, 1971.
14

CONSTITUENT QUARK PAIR PRODUCTION IN A POTENTIAL MODEL OF MESONS (CHARMONIUM, UPSILONIUM)

Unknown Date (has links)
The coupling of primitive qq meson states to four-quark qq qq states is investigated. The basic mechanism is the production of a massive quark-antiquark pair. The Feynman diagram for this process is considered and, with suitable approximations, this diagram yields a coupling operator. The heavy meson systems cc and bb are treated in some detail. Energy shifts for the first three J('P) = 1('-) states in charmonium are found to be in the range 50-80 MeV. The calculated width of the state (psi)'' is 14 MeV. The decay (psi)'(--->)(psi)(eta) is treated as a two-stage process of pair production followed by quark exchange and a width of 1.6 keV is obtained. An attempt is made to study the lighter meson systems ss and nn. Using a coupling operator similar to that used for the heavy mesons, the widths of the (phi) and (rho) mesons are determined to within an order of magnitude. / Source: Dissertation Abstracts International, Volume: 45-09, Section: B, page: 2963. / Thesis (Ph.D.)--The Florida State University, 1984.
15

MANY-PION PRODUCTION IN POSITIVE PION-DEUTERON REACTIONS AT 15 GEV/C

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 41-07, Section: B, page: 2654. / Thesis (Ph.D.)--The Florida State University, 1980.
16

Direct photon production and search for excited quarks with the D-zero detector

Unknown Date (has links)
This thesis presents a measurement of the inclusive cross-section for prompt photon production as a function of the invariant mass of the photon and highest energy jet in the final state. The experimental cross section is compared with a next-to-leading logarithm Quantum Chromodynamics (QCD) theoretical calculation. Also presented is a mass-fitting analysis in which the photon-jet invariant mass distribution is examined for evidence of excited quark production and decay, a signature of quark compositeness. No evidence of excited quark production was found. An upper limit on the excited quark cross section was established. This upper limit was compared with a theoretical prediction to set a lower limit on the mass of excited quarks of 531 GeV/$c\sp2,$ according to the assumptions of the model. / Source: Dissertation Abstracts International, Volume: 57-01, Section: B, page: 0420. / Major Professor: Horst Wahl. / Thesis (Ph.D.)--The Florida State University, 1995.
17

Study of the positive kaon neutral antikaon negative pion system produced in the reaction antiproton-proton going to positive kaon neutral antikaon negative pion + chi at 8 GeV/c

Unknown Date (has links)
The results of an amplitude analysis to determine the spin-parity components of the $K\sp+{\bar K\sp0} \pi\sp{-}$ system produced in the reaction ${\bar p}p\to K\sp+{\bar K\sp0}\pi\sp-$ + X at 8 GeV/c are presented. This experiment has better particle identification than the previously reported results examining this reaction. A total of 3595 events was collected in the mass range 1.24-1.56 GeV/c$\sp2$. The data were collected at the Brookhaven National Laboratory Multi-Particle Spectrometer. Two peaks are observed in the $K\sp+{\bar K\sp0}\pi\sp-$ mass spectrum, one at (1279 $\pm$ 2) MeV/c$\sp2$ with a width of 21 $\pm$ 2) MeV/c$\sp2$, and one at (1417 $\pm$ 3) MeV/c$\sp2$ with a width of (62 $\pm$ 5) MeV/c$\sp2$. / There is evidence for two resonances around 1.3 GeV/c$\sp2$. The $J\sp{PG}$ = 1$\sp{++}$ resonance that peaks near 1.27 Gev/c$\sp2$ is identified with the $f\sb1$(1285). The $J\sp{PG}$ = 0$\sp{-+}$ resonance observed at the same mass is identified with the $\eta$(1280). / In the 1.4 GeV/c$\sp2$ range, the data are consistant with the presence of at least one $J\sp{PG}$ = 0$\sp{-+}$ resonance that peaks near 1.43 GeV/c$\sp2$. This resonance decays only to $a\sb{0}\pi$. There is also evidence for a 1$\sp{++}K\sp{\*}K$ resonance that peaks around 1.40 GeV/c$\sp2$. These results are in agreement with the results from the partial wave analysis performed by members of this collaboration on the $K\sp+{\bar K\sp0}\pi\sp-$ system produced in the reaction $\pi\sp-p\to K\sp+{\bar K\sp0}\pi\sp-n$ at 8 GeV/c. / This experiment also examined the reactions ${\bar p}p\to{\bar \Lambda}p+\pi s+X$ in a search for the U(3100). No evidence for the U(3100) is observed. / Source: Dissertation Abstracts International, Volume: 51-09, Section: B, page: 4405. / Major Professor: Vasken Hagopian. / Thesis (Ph.D.)--The Florida State University, 1990.
18

Positive kaon neutral antikaon negative pion production in negative kaon proton interactions at 8 GeV/c

Unknown Date (has links)
K$\sp- p$ interactions at 8 GeV/c have been produced at Brookhaven National Laboratory's Multi-Particle Spectrometer to study the final state $K\sp+{\bar K\sp0}\pi\sp-$ in the mass range 1-2 GeV/c$\sp2$. A total of 1711 events have been produced in the reaction $K\sp- p\to(K\sp+{\bar K\sp0}\pi\sp-$) + Y where Y is a neutral baryon with strangeness $-$1. The Y's identified include the $\Lambda$(1115), $\Sigma$(1192), $\Sigma$(1385), and $\Lambda$(1530). / We see no clear signals for the resonances D(1285), E(1420), and $D\sp\prime$(1520). Upper limits for the production cross sections of these mesons are computed. Through comparison with data obtained in the reaction $\pi\sp- p\to$($K\sp+{\bar K\sp0}\pi\sp-$) + n we find that the production cross sections for the D(1285) and E(1420) are at least an order of magnitude smaller for the $K\sp{-}p$ interactions than for the $\pi\sp{-}p$ interactions, while that of the $D\sp\prime$(1530) may be of the same order of magnitude for both interactions, indicating the possibility of a significant $s{\bar s}$ component. / Also, a Partial Wave Analysis shows some evidence of an interference of 1$\sp{++}$ and 1$\sp{+-} J\sp{PG}$ states near 1.4 GeV/c$\sp2$. The 1$\sp{+-}$ wave appears to be the strongest in this mass region. / Source: Dissertation Abstracts International, Volume: 51-09, Section: B, page: 4405. / Major Professor: Vasken Hagopian. / Thesis (Ph.D.)--The Florida State University, 1990.
19

Experimental determination of the average fraction of jet momentum carried by the leading hadrons produced at large transverse momenta

Unknown Date (has links)
The average fraction ($\equiv\langle{\cal Z}\rangle$) of jet momentum carried by the associated charged leading hadron has been determined in the reaction $p$ + $N\ \to\ h\sb1$ + $h\sb2$ + $X$ where $h\sb1$ and $h\sb2$ were two high P$\sb\bot$ hadrons, leading particles of two jets produced at high P$\sb\bot$. A 800 GeV/c proton beam and four nuclear targets: beryllium, aluminium, iron and tungsten were used. The data were taken at the Fermi National Accelerator Laboratory from November 1987-February 1988. / The detector was a double arm magnetic spectrometer, with two sampling calorimeters for real-time event selection and was capable of operating at a high interaction rate ($\approx$2.5 $\times$ 10$\sp6$ interactions per second). / $\langle{\cal Z}\rangle$, connected to the fragmentation process of the scattered partons in the QCD-parton model, has been determined as a function of the transverse momentum of the leading hadron and the cosine of the scattering angle of the leading hadron pair in the di-hadron C.o.M. system, for positive, negative and both sign charges of the leading hadron and for each target. / The fragmentation process was found to be independent of nuclear effects and the amount of nuclear matter crossed by the fragmenting parton. The $\langle{\cal Z}\rangle$ distributions agree with the QCD-parton model predictions for single independent parton-parton scattering and independent fragmentation process. / Agreement has also been found between these data and previous published ones obtained in a $pp$ collider experiment confirming the independence of the fragmentation process from nuclear effects in high P$\sb\bot$ interactions. / Source: Dissertation Abstracts International, Volume: 51-04, Section: B, page: 1882. / Major Professor: David A. Levinthal. / Thesis (Ph.D.)--The Florida State University, 1990.
20

Next-to-leading-log QCD calculation of symmetric dihadron production

Unknown Date (has links)
We present a technique for using a Monte Carlo method to perform the phase space integrations used in calculating the next-to-leading-logarithm, QCD contribution to symmetric dihadron production. We show that this method is relatively simple, straightforward, and sufficiently flexible so as to be applicable to a broad range of next-to-leading-log calculations. / Source: Dissertation Abstracts International, Volume: 50-03, Section: B, page: 0998. / Major Professor: Joseph F. Owens. / Thesis (Ph.D.)--The Florida State University, 1989.

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