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A Correlation of the Habitat Factors with the Quantity of Bacterial Colonies as Observed by the Direct Microscopic Method on Twenty Soils of Denton County, Texas

Description: The aim of this study is to determine what factors are most important in controlling the number of bacterial colonies found in twent represntative Denton County (Texas) soils during the growing season.
Date: August 1937
Creator: Roach, Cornelia Ann
Partner: UNT Libraries

A possible hadronic excess in psi(2S) decay and the rho pi puzzle

Description: We study the so-called {rho}{pi} puzzle of the {psi}(2S) decay by incorporating two inputs; the relative phase between the one-photon and the gluonic decay amplitude, and a possible hadronic excess in the inclusive nonelectromagnetic decay rate of {psi}(2S). We look into the possibility that the hadronic excess in {psi}(2S) originates from a decay process of long-distance origin which is absent from the J/{upsilon} decay. We propose that the amplitude of this additional process happens to nearly cancel the short-distance gluonic amplitude in the exclusive decay {psi}(2S) {yields} 1{sup -}0{sup -} and turn the sum dominantly real in contrast to the J/{psi} decay. We present general consequences of this mechanism and survey two models which might possibly explain the source of this additional amplitude.
Date: November 9, 2000
Creator: Suzuki, Mahiko
Partner: UNT Libraries Government Documents Department

Lightest Isotope of Bh Produced Via the 209Bi(52Cr,n)260BhReaction

Description: The lightest isotope of Bh known was produced in the new {sup 209}Bi({sup 52}Cr,n){sup 260}Bh reaction at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. Positive identification was made by observation of eight correlated alpha particle decay chains in the focal plane detector of the Berkeley Gas-Filled Separator. {sup 260}Bh decays with a 35{sub -9}{sup +19} ms half-life by alpha particle emission mainly by a group at 10.16 MeV. The measured cross section of 59{sub -20}{sup +29} pb is approximately a factor of four larger than compared to recent model predictions. The influences of the N = 152 and Z = 108 shells on alpha decay properties are discussed.
Date: May 7, 2007
Creator: Nelson, Sarah L.; Gregorich, Kenneth E.; Dragojevic, Irena; Garcia, Mitch A.; Gates, Jacklyn M.; Sudowe, Ralf et al.
Partner: UNT Libraries Government Documents Department

Radiative higgs boson decays H {yields} f{anti f}{gamma}

Description: Higgs boson radiative decays of the form H {r_arrow} f{ovr f}{gamma} are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks are given. We also present e{ovr e} invariant mass distributions for H {r_arrow} e{ovr e}{gamma}, which illustrate the importance of the photon pole contribution and the effects of the box diagrams. 4 refs., 6 figs.
Date: October 10, 1996
Creator: Abbasabadi, A.; Bowser-Chao, D.; Repko, W.W. & Dicus, D.A.
Partner: UNT Libraries Government Documents Department

Neutrinoless Double Beta Decay in Light of SNO Salt Data

Description: In the SNO data from its salt run, probably the most significant result is the consistency with the previous results without assuming the 8B energy spectrum. In addition, they have excluded the maximal mixing at a very high confidence level. This has an important implication on the double beta decay experiments. For the inverted or degenerate mass spectrum, we find bar<m_nu>_ee bar> 0.013 eV at 95percent CL, and the next generation experiments can discriminate Majorana and Dirac neutrinos if the invertedor degenerate mass spectrum will be confirmed by the improvements in cosmology, tritium data beta decay, or long-baseline oscillation experiments.
Date: September 11, 2003
Creator: Murayama, Hitoshi & Pena-Garay, Carlos
Partner: UNT Libraries Government Documents Department

Squark Mixing Contributions to CP violating phase gamma

Description: We investigate the possibility that the CP violation due to the soft supersymmetry breaking terms in squark mixing can give significant contributions to the various $\gamma$ related parameters in B decays, different from those of the Standard Model. We derive the new limits on $(\delta^u_12)_LL,LR,RR$ and on $(\delta^d_23)_LL,LR,RR$ from the recent data on $D^0$--$\barD^0$ oscillation as well as those on $B_s^0$--$\barB_s^0$ oscillation. We show that, together with all the other constraints, the currents limits on these parameters still allow large contributions to the CP violating phases in $B_s^0$--$\bar{B_s}^0$ as well as $D^0$--$\barD^0$ oscillations which will modify some of the proposed measurements of $\gamma$ parameters in CP violating B decays. However, the current constraints already dictate that the one-loop squark mixing contributions to various B decay amplitudes cannot be competitive with that of the Standard Model (SM), at least for those B decay modes which are dominated the tree level amplitudes within the SM, and therefore they are not significant in contributing to CP asymmetries in the corresponding B decays.
Date: September 17, 2001
Creator: Chang, Darwin; Chang, We-Fu; Keung, Wai-Yee; Sinha, Nita & Sinha, Rahul
Partner: UNT Libraries Government Documents Department

Parametric forms and the inductive response of a permeable conducting sphere

Description: At early time, the time derivative of the response of isolated conductive bodies to step function excitation decays as t-1/2 (under a quasi-static approximation). One simple parametric form for the response with correct early time behavior is k'(1 + t1/2/a1/2)-beta e-t/gamma. For a conducting magnetic sphere, parameter values are determined from the high and low frequency limit responses, together with two time scales taken from the form of the analytic solution. Parameters alpha and gamma correspond to transition times, for transition from an early time t-1/2 derivative response, and to late time exponential decay. For conducting spheres with high permeability, increasing the permeability moves the transition from early time behavior earlier in inverse proportion to the relative permeability mu r, and increases the time constant of the late time decay in proportion to mu r. Magnitude parameter k' corresponds to the difference between high frequency and low frequency limit responses.
Date: December 11, 2003
Creator: Smith, J. Torquil; Morrison, H. Frank & Becker, Alex
Partner: UNT Libraries Government Documents Department

The Decay of the Yoknapatawpha Aristocracy in the Works of William Faulkner

Description: This study consists of an examination in detail of those facets of character, and conduct arising from character, which specifically account for the decay of the aristocracy of Yoknapatawpha; and by way of emphasis, of the specifically regenerative attitudes and actions which have sufficed to preserve various individuals of this class who have endured as fully adequate human beings.
Date: June 1962
Creator: Pyland, Joel L.
Partner: UNT Libraries

Radiative Decays, Nonet Symmetry and SU(3) Breaking

Description: We re-examine the problem of simultaneously describing in a consistent way all radiative and leptonic decays of light mesons (V {yields} P{gamma}, P {yields} V{gamma}, P {yields} {gamma}{gamma}, V {yields} e{sup +}e{sup -}). For this purpose, we rely on the Hidden Local Symmetry model in both its anomalous and non-anomalous sectors. We show that the SU(3) symmetry breaking scheme proposed by Bando, Kugo and Yamawaki, supplemented with nonet symmetry breaking in the pseudoscalar sector, allows one to reach a nice agreement with all data, except for the K*{sup {+-}} radiative decay. An extension of this breaking pattern allows one to account for this particular decay mode too. Considered together, the whole set of radiative decays provides a pseudoscalar mixing angle {theta}{sub P} {approx_equal} and a value for {theta}{sub V} which is {approx_equal} 3{sup o} from that of ideal mixing. We also show that it is impossible, in a practical sense, to disentangle the effects of nonet symmetry breaking and those of glue inside the {eta}{prime}, using only light meson decays.
Date: June 30, 1999
Creator: O'Connell, Heath B
Partner: UNT Libraries Government Documents Department

The decay pi{sup 0} {yields} gamma gamma to next to leading order in Chiral Perturbation Theory

Description: The pi{sup 0} {yields} gamma gamma decay width is analyzed within the combined framework of Chiral Perturbation Theory and the 1/N{sub c} expansion up to order(p{sup 6}) and order(p{sup 4} x 1/N{sub c}) in the decay amplitude. The eta' is explicitly included in the analysis. It is found that the decay width is enhanced by about 4% due to the isospin-breaking induced mixing of the pure U(3) states. This effect, which is of leading order in the low energy expansion, is shown to persist nearly unchanged at next to leading order. The chief prediction Gamma{sub pi}0{sub {yields}gamma gamma} = 8.10 eV is estimated to have an uncertainty of less than 1%. Observations on the eta and eta' can also be made, especially about their mixing, which is shown to be significantly affected by next to leading order corrections.
Date: May 1, 2002
Creator: Goity, J.L.; Bernstein, A.M.; Donoghue, J.F. & Holstein, B.R.
Partner: UNT Libraries Government Documents Department

New Radionuclide Generator Systems for Use in Nuclear Medicine

Description: A current emphasis in nuclear medicine is to better match the physical lifetime of the radionuclides used in vivo for diagnosis and treatment to the biological lifetime of the diagnostic procedure or to minimize radiation dose to areas other than those to be treated. In many cases the biological lifetime is on the order of minutes. Since the direct production of radionuclides with half lives of minutes requires the user to be near a suitable reactor or accelerator, this study was undertaken to produce short-lived radionuclides indirectly. If a long-lived radionuclide decays into a short-lived radionuclide, quick separation of the daughter activity from the parent enables the user to have a short-lived daughter while freeing him from the constraint of proximity to a cyclotron. Systems where a short-lived daughter is separated from a long-lived parent are called radionuclide generators. Two generator systems were developed for use in nuclear medicine, one in diagnostic work and the other for therapeutic work. The yield and breakthrough characteristics were within the limits required to minimize unnecessary radiation exposure in patients. Two parent radionuclides were produced using the beams available from medium energy cyclotrons. The yield was high enough to produce generators that would be useful in clinical applications.
Date: 1979
Creator: Atcher, Robert Whitehill
Partner: UNT Libraries Government Documents Department

A,B,C`s of nuclear science

Description: This introductory level presentation contains information on nuclear structure, radioactivity, alpha decay, beta decay, gamma decay, half-life, nuclear reactions, fusion, fission, cosmic rays, and radiation protection. Nine experiments with procedures and test questions are included.
Date: August 7, 1995
Creator: Noto, V.A.; Norman, E.B.; Chan, Yuen-Dat; Dairiki, J.; Matis, H.S.; McMahan, M.A. et al.
Partner: UNT Libraries Government Documents Department

Nuclear Thermodynamics of the Heaviest Elements. II

Description: The masses of the isotopes of the heaviest elements have been calculated from known decay data in the region, extended by means of decay energies calculated from closed decay-energy cycles and estimated from the systematics of alpha and beta decay energies. The absolute values of the masses are based on the mass-spectrometrically determined mass of Pb{sup 208} and a few measured neutron binding energies. The half-life systematics of alpha decay and spontaneous fission are also presented, and some predictions of the properties of as yet undiscovered nuclides are made.
Date: October 1, 1957
Creator: Foreman Jr., Bruce M. & Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department

Nuclear Thermodynamics of the Heaviest Elements. II

Description: The masses of the isotopes of the heaviest elements have been calculated from known decay data in the region, extended by means of decay energies calculated from closed decay-energy cycles and estimated from the systematics of alpha and beta decay energies. The absolute values of the masses are based on the mass-spectrometrically determined mass of Pb{sup 208} and a few measured neutron binding energies. The half-life systematics of alpha decay and spontaneous fission are also presented, and some predictions of the properties of as yet undiscovered nuclides are made.
Date: January 1, 1958
Creator: Foreman Jr., Bruce M. & Seaborg, Glenn T.
Partner: UNT Libraries Government Documents Department

Electrical Signal Path Study and Component Assay for the MAJORANA N-Type Segmented Contact Detector

Description: The purpose of the present electrical signal path study is to explore the various issues related to the deployment of highly-segmented low-background Ge detectors for the MAJORANA double-beta decay experiment. A significant challenge is to simultaneously satisfy competing requirements for the mechanical design, electrical readout performance, and radiopurity specifications from the MAJORANA project. Common to all rare search experiments, there is a very stringent limit on the acceptable radioactivity level of all the electronics components involved. Some of the findings are summarized in this report.
Date: February 24, 2009
Creator: Amman, Mark; Bergevin, Marc; Chan, Yuen-Dat; Detwiler, Jason A.; Fujikawa, Brian .; Lesko, Kevin T. et al.
Partner: UNT Libraries Government Documents Department

Rare decays experimental summary and prospects

Description: I review the status and future prospects of searches for forbidden and highly kaon suppressed decays. This workshop comes as we are poised at the threshold of a new generation of rare K decay experiments. There are new experiments running or about to run at KEK, BNL, FNAL, and CERN. In another year or so these will be joined by the KLOE experiment at DA{Phi}NE. The good news is that it`s a very exciting time. The bad news, at least for a reviewer, is that there aren`t too many new results. Thus I`ll be giving a little more attention than usual to what the experimenters expect to do. My discussion of rare K decays covers processes that are forbidden in the Standard Model, those that highly suppressed and to a smaller extent, those that are merely discouraged.
Date: December 31, 1996
Creator: Littenberg, L.
Partner: UNT Libraries Government Documents Department

Heavy meson observables via Dyson-Schwinger equations

Description: The authors summarize a Dyson-Schwinger-equation-based calculation of an extensive range of light- and heavy-meson observable, characterized by heavy-meson leptonic decays, semileptonic heavy-to-heavy and heavy-to-light transitions--B {yields} D*, D, {rho}, {pi}; D {yields} K*, K, {pi}, radiative and strong decays--B*{sub (s)} {yields} B{sub (s)}{gamma}; D*{sub (s)}{gamma} and the rare B {yields} K*{sub {gamma}} flavor-changing neutral-current process. In the calculation the heavy-quark mass functions are approximated by constants, interpreted as their constituent-mass: {cflx M}{sub c} = 1.32GeV and {cflx M}{sub b} = 4.65 GeV.
Date: June 28, 2000
Creator: Ivanov, M. A.
Partner: UNT Libraries Government Documents Department

Quantitative and qualitative measures of decomposition: Is there a link?

Description: Decomposition rates of loblolly pine coarse woody debris (CWD) were determined by mass loss and wood density changes for trees that differed in source of mortality (natural, girdle-poison, and felling). Specifically, three treatments were examined: (1) control (CON): natural mortality; (2) CD: 5-fold increase in CWD compared with the CON; and (3) CS: 12-fold increase in snags compared with the CON. The additional CWD in the CD treatment plots and the additional snags in the CS plots were achieved by felling (for the CD plots) or girdling followed by herbicide injection (for the CS plots) select trees in these plots. Consequently,mortality on the CD plots is due to natural causes and felling. Likewise, mortality on the CS plots is due to natural causes and girdle-poison. In each treatment plot, mortality due to natural causes was inventoried since 1997, whereas mortality due to girdle-poison and felling were inventoried since 2001. No significant difference was detected between the rates of decomposition for the CWD on these treatment plots, indicating that source of the tree mortality did not influence rates of decomposition once the tree fell. These experimental measures of decomposition were compared with two decay classification systems (three- and five-unit classifications) to determine linkages. Changes in wood density did not correlate to any decay classification, whereas mass loss had a weak correlation with decay class. However, the large degree of variation limits the utility of decay classification systems in estimating mass loss.
Date: March 1, 2009
Creator: Eaton, Robert, J. & Sanchez, Felipe, G.
Partner: UNT Libraries Government Documents Department

An Investigation of the Neutral Cascade Muon Semileptonic Decay and its Observation at KTeV, Fermilab

Description: The authors report an investigation of the semileptonic decay {Xi}{sup 0} {yields} {sigma}{sup +} {mu}{sup -}{bar {nu}}{sub {mu}}. This decay was observed for the first time with nine identified events using the KTeV beam line and detector at Fermilab. The decay is normalized to the {Xi}{sup 0} beta decay mode and yields a value for the ratio of decay rates {Lambda}({Xi}{sup 0} {yields} {Sigma}{sup +} {mu}{sup -}{bar {nu}}{sub {mu}})/{Lambda}({Xi}{sup 0} {yields} {Sigma}{sup +}e{sup -}{bar {nu}}{sub e}) of (1.8{sub -0.5}{sup +0.7}(stat.) {+-} 0.2(syst.)) x 10{sup -2} at the 68.27% confidence level, being the official measurement of KTeV Collaboration. They also used the dominant decay {Xi}{sup 0} {yields} {Lambda}{pi}{sup 0}({Lambda} {yields} p{pi}{sup -}) as normalization mode in an independent analysis which corroborated with the main result. In addition, a new measurement of the {Xi}{sup 0} {yields} {Sigma}{sup +} e{sup -}{bar {nu}}{sub e} branching ratio is presented, based on 1139 events and normalized to the {Xi}{sup 0} {yields} {Lambda}{pi}{sup 0}({Lambda} {yields} p{pi}{sup -}) decay mode. The results are in agreement with the SU(3) flavor symmetric quark model.
Date: July 1, 2005
Creator: Gomes, Ricardo Avelino & U., /Campinas State
Partner: UNT Libraries Government Documents Department

Recent BaBar Results on $B$ Decays

Description: Several recent key results from the BABAR experiment are presented, most using 383.6 fb{sup -1} of data. In particular, the search for B{sup +} {yields} {tau}{sup +}{nu}, inclusive and exclusive measurements of |V{sub ub}|, measurements of b {yields} d{gamma} decays and new observations of rare charmless hadronic decays. The new results provide important experimental constraints on the Standard Model and new physics models. Keywords: B decays; flavor; leptonic; semi-leptonic, radiative, hadronic.
Date: November 15, 2011
Creator: Clark, P.J. & U., /Edinburgh
Partner: UNT Libraries Government Documents Department

A Search for the Decay B+ to tau+ nu_tau

Description: We search for the rare leptonic decay B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}} in a sample of 232 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the SLAC PEP-II B-Factory. Signal events are selected by examining the properties of the B meson recoiling against the semileptonic decay B{sup -} {yields} D*{sup 0}{ell}{bar {nu}}{sub {ell}}. We find no evidence for a signal and set an upper limit on the branching fraction of {Beta}(B{sup +} {yields} {tau}{sup +} {nu}{sub {tau}}) < 2.8 x 10{sup -4} at the 90% confidence level. We combine this result with a previous, statistically independent BABAR search for B{sup +} {yields} {tau}{sup +} {nu}{sub {tau}} to give an upper limit of {Beta}(B{sup +} {yields} {tau}{sup +} {nu}{sub {tau}}) < 2.6 10{sup -4} at the 90% confidence level.
Date: July 27, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department