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in subjects: "Lifetime"

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Quark-diagram classification of charm decays

The decays of charm mesons are described in terms of quark-diagram amplitudes. Experimental implications of these amplitudes are also discussed.

Date: May 1, 1980

Creator: Rizzo, T. G. & Wang, L. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Review of recent measurements of charmed particle lifetimes using emulsions

This talk is a review of results which have been reported during the past year on charmed particle decays in emulsions.

Date: December 1, 1979

Creator: Voyvodic, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Biological Effects of Blast. Technical Progress Report

The current state of knowledge relevant to biological blast effects was summarized in a selective manner. Initially, five problems of concern to those who would relate the environmental variations produced by nuclear weapons with biological response and hazard assessment were pointed out. Primary, secondary, tertiary, and miscellaneous blast effects were defined and selected interspecies experimental data of a physical and pathophysiological nature useful in estimating human response were prese… more

Date: December 1, 1961

Creator: White, C. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Excited-state proton-transfer kinetics in 1-naphthol, 1-naphthol-sulfonates, and organometallic complexes

The dissociation of 1-naphthol in aqueous solution occurs so rapidly that the fluorescence from the neutral form, ROH, has been previously described as completely extinguished or hardly noticeable. Apparently nearly all of the fluorescence originates from the naphtholate ion. This paper reports on the proton-transfer characteristics of a series of 1-naphthol compounds, and also reports preliminary data on excited-state proton transfer in an organometallic complex of ruthenium.

Date: July 1, 1980

Creator: Shapiro, S. L.; Winn, K. R. & Clark, J. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Damage to fused silica windows while under simultaneous exposure to flowing solvents and laser radiation and 308nm

This paper reports the results of a study to determine the degrading effects of flowing dye solvents on the laser damage threshold of fused-silica windows at 308nm. Thresholds were measured at the SiO/sub 2/solvent interface in a test cell. Bare SiO/sub 2/ tested in air at 308nm (20ns) typically exhibits a threshold ranging from 4 to 10 Jcm/sup 2/; with the solvent cyclohexane in contact, a threshold as low as 0.3 Jcm/sup 2/ was measured. The damage data indicate that window lifetime (number of… more

Date: January 1, 1987

Creator: Mauro, B. R.; Foltyn, S. R. & Sanders, V. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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N and. delta. resonances: an experimental review

Experimental progress in N and ..delta.. resonances since the Oxford baryon conference is reviewed. The review concentrates on hadronic channels, and on developments of the last one or two years. The topics reviewed include the antiproton lifetime; the ..delta../sup + +/ magnetic moment; measurements of ..pi..N elastic and charge-exchange scattering in the ..delta.. region, the eta n threshold region, and the high-mass region; partial wave analyses of ..pi..N ..-->.. ..pi..N; measurements of tw… more

Date: July 1, 1980

Creator: Kelly, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Properties of leptons

The properties of the electron, muon, tau, and their neutrinos are reviewed. Three discrepancies in our understanding of those properties are discussed: the lifetime of orthopositronium, the mass spectra of e{sup +}e{sup -} pairs produced in heavy ion collisions, and the 1-charged particle modes problem in tau decays. The review concludes with a discussion of what we need to learn about the tau and the consequent need for a tau-charm factory. 68 refs., 7 figs., 8 tabs.

Date: December 1, 1989

Creator: Perl, Martin L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Nuclear collectivity and complex alignment mechanisms in light tungsten and osmium nuclei

During the past few years there have been significant advances in our understanding of nuclei excited into states of high angular momentum. The development of large multi-detector arrays for {gamma}-{gamma} coincidence spectroscopy studies has propelled the amount of new experimental information available and this has been complemented by notable advances in the theoretical treatments of high-spin phenomena. To provide yet a more detailed understanding of the structure of these high-spin states… more

Date: January 1, 1989

Creator: Johnson, N.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Ratio of D/sup 0/ and D/sup +/ lifetimes from their semileptonic decays

The conventional expectation for the decays of D mesons assumes that the charm quark decays in the presence of light, spectator quarks and thus the lifetimes of both charged and uncharged states are equal. In this article, evidence is presented from DELCO (at SPEAR) that the D lifetimes are quite different for neutral and charged mesons, and the results which have also become available from other experiments are reviewed.

Date: June 1, 1980

Creator: Donaldson, G.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Bubble-chamber experiments on charmed-particle lifetimes

The three current bubble-chamber experiments on charmed-particle lifetimes are compared. Their most recently released results are discussed.

Date: July 1, 1982

Creator: Field, R.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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First wall and limiter lifetime in pulsed tokamak reactors

This study concentrates on the structural integrity of certain reactor subsystems under cyclic operation to answer the question: how long a burn pulse is needed to achieve the benefits of steady-state operation. Component lifetime in the steady-state is limited by three effects: radiation damage, disruptions, and sputtering erosion. Cyclic operation modifies one of these (the number of disruptions may increase with the number of burn cycles) and introduces a fourth life limit, thermal fatigue. … more

Date: December 1, 1983

Creator: Ehst, D.; Majumdar, S.; Cha, Y. & Hassanein, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Emission cross sections and energy extraction for the mid-infrared transitions of Er, Tm, and Ho in oxide and fluoride crystals

Emission cross sections have been measured for the transitions between the two lowest spin orbit multiplets of Er, Tm, and Ho in several fluoride and oxide crystals. Properties affecting energy extraction efficiency are summarized and pulsed extraction performance is calculated for several of these quasi-three-level laser media. 4 refs., 9 figs.

Date: April 1, 1991

Creator: Chase, L. L.; Payne, S. A.; Smith, L. K.; Kway, W. L. & Krupke, W. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Positron lifetimes in solids from first principles calculations

We present a first principles method for calculating positron lifetimes in solids, based on self-consistent calculations using the Linear Muffin-Tin Orbital method. Local density approximations are used for both electron-electron and electron-positron interactions. Results are presented for a variety of elemental metals and vacancies to demonstrate the reliability of this approach. Theoretical calculations of positron lifetimes can be used to interpret experimental data. As an examples of this,… more

Date: August 7, 1991

Creator: Sterne, P. A.; O'Brien, J. C.; Howell, R. H. & Kaiser, J. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Proton decay: 1982

Employing the current world average ..lambda../sub MS/ = 0.160 GeV as input, the minimal Georgi-Glashow SU(5) model predicts sin/sup 2/theta/sub W/(m/sub W/) = 0.214, m/sub b//m/sub tau/ approx. = 2.8 and tau/sub p/ approx. = (0.4 approx. 12) x 10/sup 29/ yr. The first two predictions are in excellent agreement with experiment; but the implied proton lifetime is already somewhat below the present experimental bound. In this status report, uncertainties in tau/sub p/ are described and effects of… more

Date: March 4, 1982

Creator: Marciano, William J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Neutrino fluctuat nec mercitur: are fossil neutrinos detectable

A brief report is presented on the question whether light (few eV to approx. 100 eV) neutrinos left over from the big bang are detectable. The answer is perhaps. If the weak current of leptons, like those of quarks, are not diagonal in mass eigenstates, a neutrino will decay into a lighter neutrino and a monochromatic photon. The corresponding photon line may be detectable provided: neutrinos are heavy enough to participate in galaxy clustering and neutrino lifetimes are, as in some weak intera… more

Date: April 1, 1980

Creator: De Rujula, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Recent results from MAC

Some preliminary results from the MAC detector at PEP are presented. These include measurements of the angular distribution of ..gamma gamma.., ..mu mu.. and tau tau final states, a determination of the tau lifetime, a measurement of R, and a presentation of the inclusive muon p/sub perpendicular/ distribution for hadronic events.

Date: May 1, 1982

Creator: MAC Collaboration

Item Type: Article

Partner: UNT Libraries Government Documents Department

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High spin isomers in /sup 153/Er

Energy levels of /sup 153/Er were investigated with four NaI detectors in coincidence with a Ge(Li) detector. The existence of two long-lived high-spin isomers was confirmed, and their positions and decays were established. 1 figure. (RWR)

Date: January 1, 1980

Creator: Horn, D.; Young, G. R.; Lister, C. J. & Baktash, C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Picosecond spectroscopic search for electron transfer reactions in dimeric and trimeric reaction center models containing pyrochlorophyll/sub a/

To further understanding of the light driven electron transfer reactions found in natural photosystems, dimeric and trimeric model molecules containing PChl/sub a/ were studied. The potential donor and acceptor subunits were covalently linked to form a single large molecule. The distance between the donor and acceptor subunits was altered by using both 10 atom and 5 atom chains. The effects of altering the relative orientation of the donor and acceptor were probed by contrasting the kinetics ob… more

Date: January 1, 1980

Creator: Netzel, T L; Bucks, R R; Boxer, S G & Fujita, I

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The physics of heavy flavors

We review the physics of heavy quark flavors, including weak decays, onium, tau leptons, mixing, the Kobayashi-Maskawa matrix, and CP violation in B decay. 36 refs., 12 figs.

Date: December 1, 1987

Creator: Gilman, Frederick J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Thermal stress and creep fatigue limitations in first wall design

The thermal-hydraulic performance of a lithium cooled cylindrical first wall module has been analyzed as a function of the incident neutron wall loading. Three criteria were established for the purpose of defining the maximum wall loading allowable for modules constructed of Type 316 stainless steel and a vanadium alloy. Of the three, the maximum structural temperature criterion of 750/sup 0/C for vanadium resulted in the limiting wall loading value of 7 MW/m/sup 2/. The second criterion limite… more

Date: January 1, 1977

Creator: Majumdar, S.; Misra, B. & Harkness, S.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Photoelectronic properties of zinc phosphide crystals, films and heterojunctions. Quarterly progress report No. 2, July 1-September 30, 1979

The closed tube horizontal growth method has been pursued for the growth of single crystals of Zn/sub 3/P/sub 2/. The rate of material transport was increased by increasing the temperature difference between source and growth regions and by decreasing the distance involved. A boule with only 2 grains in a 12 mm diameter has been obtained. The as-grown resistivity of this single crystal Zn/sub 3/P/sub 2/ was 50 ohm-cm, which was reduced to 10 ohm-cm by subsequent annealing in hydrogen at 410/sup… more

Date: October 1, 1979

Creator: Bube, R.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Computer programs, to determine credible regions for Weibull distribution

Computer software for analyzing life test data with a Weibull distribution is given. The programs calculate and plot the 95, 90, 50 and 5% highest probability density contours and the maximum likelihood estimators on the same frame for all sets of data. They also calculate the maximum likelihood estimator of mean life and conservative 95, 90, 50 and 5% credible intervals on mean life. The programs are used to analyze data on the lifetimes of Kevlar/Epoxy spherical vessels and the results are gi… more

Date: unknown

Creator: Agrawal, A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Large aspect ratio tokamak study

The Large Aspect Ratio Tokamak Study (LARTS) investigated the potential for producing a viable long burn tokamak reactor through enhanced volt-second capability of the ohmic heating transformer by employing high aspect ratio designs. The plasma physics, engineering, and economic implications of high aspect ratio tokamaks were accessed in the context of extended burn operation. Plasma startup and burn parameters were addressed using a one-dimensional transport code. The pulsed electrical power r… more

Date: January 1, 1979

Creator: Reid, R. L.; Holmes, J. A.; Houlberg, W. A.; Peng, Y. K. M.; Strickler, D. J.; Brown, T. G. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Surface areas by positron annihilation spectroscopy

Positron annihilation spectroscopy (PAS) is a technique for measuring the length of time that a positron exists after being injected into a specific material. Lifetime measurements have been used for studying defects in metals. These imperfections affect the localized electron densities which in turn influence the lifetime of the positron before annihilation occurs. Electron density differences are also associated with surfaces. This paper describes the PAS technique and shows a correlation bet… more

Date: January 1, 1985

Creator: Dale, J.M.; Rosseel, T.M.; Hulett, L.D.; Venkateswaran, K.; Jean, Y.C. & Fuller, E.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department