CERN Document Server

Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the \\sigma(600) meson. We show that the kaon loop mechanism of the \\phi radiative decays, ratified by experiment, points to the four-quark nature of light scalars. We show also that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor q\\bar q mesons that are produced via two-quark transitions $\\gamma\\gamma\\to q\\bar q$. The history of spontaneous breaking of symmetry in quantum physics is discussed in Appendix.

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Wonderful opportunities await particle physics over the next decade, with the coming of the Large Hadron Collider at CERN to explore the 1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of electroweak symmetry breaking) and many initiatives to develop our understanding of the problem of identity: what makes a neutrino a neutrino and a top quark a top quark. Here I have in mind the work of the B factories and the Tevatron collider on CP violation and the weak interactions of the b quark; the wonderfully sensitive experiments at Brookhaven, CERN, Fermilab, and Frascati on CP violation and rare decays of kaons; the prospect of definitive accelerator experiments on neutrino oscillations and the nature of the neutrinos; and a host of new experiments on the sensitivity frontier. We might even learn to read experiment for clues about the ...

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We calculate the masses of the resonances D{sub s0}{sup *}(2317) and D{sub s1}(2460) as well as their bottom partners as bound states of a kaon and a D{sup (*)} - and B{sup (*)} -meson, respectively, in unitarized chiral perturbation theory at next-to-leading order. After fixing the parameters in the D{sub s0}{sup *}(2317) channel, the calculated mass for the D{sub s1}(2460) is found in excellent agreement with experiment. The masses for the analogous states with a bottom quark are predicted to be M{sub B{sup *}{sub s0}}=(5696{+-}40) MeV and M{sub B{sub s1}}=(5742{+-}40) MeV in reasonable agreement with previous analyses. In particular, we predict M{sub B{sub s1}}-M{sub B{sub s0}}{sup *}=46{+-}1 MeV. We also explore the dependence of the states on the pion and kaon masses. We argue that the kaon mass dependence of a kaonic bound state should be almost linear with slope about unity. Such a dependence is ...

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No abstract prepared.

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Detailed level and decay schemes are presented for the nuclei of the A = 101 mass chain. The level properties obtained from decay and reaction experiments are shown in the drawings. Experimental methods, references, and comments are given in the text.

CERN Document Server

Using 14M psi(2S) events taken with the BES-II detector, chi_cJ-->K+K-K+K- decays are studied. For the four-kaon final state, the branching fractions are B(chi_c0,1,2 -->K+K-K+K-)=(3.47\\pm 0.22\\pm 0.48)\\times 10^{-3}, (0.68\\pm 0.13\\pm 0.10)\\times 10^{-3}, and (1.88\\pm 0.18\\pm 0.28)\\times 10^{-3}. For the \\phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi_c0,1,2-->\\phi K+K-)=(1.02\\pm 0.22\\pm 0.15)\\times 10^{-3}, (0.44\\pm 0.14\\pm 0.07)\\times 10^{-3}, and (1.46\\pm 0.21\\pm 0.22)\\times 10^{-4}. For the \\phi\\phi final state, B(chi_{c0,2}-->\\phi\\phi)=(0.94\\pm 0.21\\pm 0.14)\\times 10^{-3} and (1.48\\pm 0.26\\pm 0.23)\\times 10^{-3}.

International Nuclear Information System (INIS)

We investigate the possibility of kaon condensation in the dense interior of neutron stars through the s-wave interaction of kaons with nucleons. We include nucleon-nucleon interactions by using simple parametrizations of realistic forces, and include electrons and muons in #beta#-equilibrium. The equation of state above the condensate threshold is derived in the mean field approximation. The conditions under which kaon condensed cores undergo a transition to quark matter containing strange quarks are also established.The critical density for kaon condensation lies in the range (2.3-5.0)#rho#_0, where #rho#_0=0.16 fm"-"3 is the equilibrium density of nuclear matter. The critical density depends largely on the value of the strangeness content of the proton, the size of which is controversial. For too large a value of the strangeness content, matter with a kaon condensate is not ...

CERN Document Server

LHC$b$ is one the four major experiments at the Large Hadron Collider (LHC) at CERN. It is custom built to look for CP violation and New Physics in rare decays of heavy flavor hadrons, like the B and D systems. Rare decays that occur via loop diagrams provide a way to probe New Physics at energy scales much higher than can be probed by direct production in experiment. In this article, the LHC$b$ prospects for such measurement with exclusive decays of the type $B \\to X_s\\gamma$ and $B\\to X_sl^+l^-$ are presented.

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Jlab experiment E01-011, carried out in 2005 in JLab Hall C, is the second generation of the hypernuclear spectroscopy experiments by the (e,e{prime}K{sup +}) reaction. The (e,e{prime}K{sup +}) reaction is complimentary to the associated production reactions (K{sup -},{pi}{sup -}), ({pi}{sup +},K{sup +}) since, due to a larger momentum transfer to a hyperon, excitations of both spin-non-flip and spin-flip states are possible. The experiment uses high quality and continuous primary electron beam to produce neutron rich hypernuclei on various targets by the electroproduction. The experimental setup consists of splitter magnet, high resolution kaon spectrometer (HKS) and electron spectrometer (Enge) implemented in new configuration, the so called 'Tilt Method'. Production data was taken on multiple targets: CH{sub 2}, {sup 6}Li, {sup 7}Li, {sup 9}Be, {sup 10}B, {sup 12}C and {sup 28}Si. ...

International Nuclear Information System (INIS)

Nuclear structure information available to May 1979 has been reviewed. The level properties obtained from decay and reaction experiments are shown in the drawings. Experimental methods, references, and comments are given in the text.

CERN Document Server

Recent observations of a large excess of cosmic-ray positrons at high energies have raised a lot of interest in leptonic decay modes of dark matter particles. Nevertheless, dark matter particles in the Milky Way halo could also decay hadronically, producing not only a flux of antiprotons but also a flux of antideuterons. We show that for certain choices of parameters the antideuteron flux from dark matter decay can be much larger than the purely secondary flux from spallation of cosmic rays on the interstellar medium, while the total antiproton flux remains consistent with present observations. We show that if the dark matter particle is sufficiently light, the antideuteron flux from dark matter decay could even be within the reach of planned experiments such as AMS-02 or GAPS. Furthermore, we discuss the prospects to observe the antideuteron flux in the near future if the steep ...

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We analyse data on forward {eta} -meson photoproduction off a proton target and extract the {eta}{yields}{gamma}{gamma} decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available {gamma}p{yields}p{eta} data for differential cross-sections and polarizations. We compare our results with present information on the two-photon {eta} -decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies. (orig.)

British Library Electronic Table of Contents (United Kingdom)

LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of scintillating bolometers. These devices promise a very efficient rejection of the alpha background, opening the way to a virtual background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is 82Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced. The sensitivity and the very promising prospects related to this project will be discussed.

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This thesis describes the analysis of the semileptonic decay D{sup 0} {yields} {bar K}{sup 0} {pi}{sup -} {mu}{sup +}{nu} using FOCUS data. FOCUS is a fixed target experiment at Fermilab that studies the physics of the charm quark. Particles containing charm are produced by photon-gluon fusion from the collision of a photon beam on a BeO target. The experiment is characterized by excellent vertex resolution and particle identification. The spectrometer consists of three systems for track reconstruction (two silicon systems and one multiwire proportional chamber system) and two magnets of opposite polarity. The polarity of the magnet is such that the events of e{sup +}e{sup -} pairs produced in the target (which constitutes the main background) travel through a central opening in the detectors without interactions. Particle momentum is measured from the deflection angle in the magnets. Three multicell Cerenkov counters are ...

International Nuclear Information System (INIS)

Water flow experiments were conducted on natural circulation decay heat removal with an electrically heated 91-rod bundle. Experimental results were compared with analytical predictions to provide thermal hydraulic characteristics for LMFBR Fuel assemblies under a low flow, typical of the natural circulation regime. The results revealed that, at low flow rate region (Re<1,200), axial friction loss in a heated bundle increases with buoyancy effect. The radial temperature profile provides some insight regarding the concept that coolant redistribution would occur. COBRA-V-I predictions are successfully proved validity in comparison with experimental results.

International Nuclear Information System (INIS)

The authors present a state-of-the-art review of natural circulation heat transfer in loop type reactor plants. Most of the examples are taken from Fast Flux Test Facility (FFTF) design experience, drawing on the authors' familiarity and a developing base of available documentation. On-going studies related to the Clinch River Breeder Reactor (CRBR) and some foreign experience are also noted where available in the literature. The emphasis is on the role of natural circulation in decay heat removal; however, free convection during either operation at power or normal shutdown does influence some aspects of the design and these are reviewed. In treating decay heat removal the topics discussed include steady state loop performance and transient dynamics for conditions immediately after scram and for the longer term which involves different considerations. The review summarizes complex dynamics, specific to ...

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The "2H(#alpha#,p#alpha#)n reaction was investigated in a kinematically complete experiment with a #alpha#-beam at energy 27.2 MeV.The "5He excited state was observed and its parameters were determinate.Coincidence spectra were fitted by contribution of sequential decay through the "5He ground and excited states.The best agreement with the data was obtained assuming the following "5He excited state parameters: E_a_n=2.8 MeV #GAMMA#=2.5 MeV.

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The existence of a cosmic neutrino background - the analogue of the cosmic microwave background - is a fundamental prediction of standard big bang cosmology. Up to now, the observational evidence for its existence is rather indirect and rests entirely on cosmological observations of, e.g., the light elemental abundances, the anisotropies in the cosmic microwave background, and the large scale distribution of matter. Here, we review more direct, weak interaction based detection techniques for the cosmic neutrino background in the present epoch and in our local neighbourhood. We show that, with current technology, all proposals are still off by some orders of magnitude in sensitivity to lead to a guaranteed detection of the relic neutrinos. The most promising laboratory search, based on neutrino capture on beta decaying nuclei, may be done in future experiments designed to measure the neutrino mass through decay kinematics. ...

CERN Document Server

Discussions on a form of a frequency spectrum of wind-driven sea waves just above the spectral maximum continue during the last three decades. In 1958 Phillips made a conjecture that wave breaking is the main mechanism responsible for the spectrum formation. That leads to the spectrum decay $\\sim \\omega^{-5}$, where $\\omega$ is the frequency of the waves. There is a contradiction between the numerous experimental data and this spectrum. The experiments show decay $\\sim\\omega^{-4}$. There are two general ways of the explanation of this phenomenon. The first one (proposed by Banner (1990)) takes into account the Doppler effect due to surface circular currents generated by long waves in the Phillips model. The second approach ascends to the work by Zakharov and Filonenko (1968). It is based on four-wave interactions in the kinetic equation and gives good agreement with the experimental data. In this article the ...

CERN Document Server

The basic theoretical milestones were the Sakata SU(3) symmetry, the Goldberg-Ne'eman composite model with SU(3) triplets having baryon number (1/3) and the Nambu color gauge Lagrangian. The transition was led in right and wrong directions by experiments interpreted by phenomenology. A "good" experiment on $\\bar p p$ annihilation at rest showed that the Sakata model predictions disagreed with experiment. A "bad" experiment prevented the use of the Goldberg-Ne'eman triplet model to predict the existence and masses of the of the $\\Xi^*$ and $\\Omega^-$. More "good" experiments revealed the existence and mass of the $\\Xi^*$ and the $\\Omega^-$ and the absence of positive strangeness baryon resonances, thus confirming the "tenfold way". Further "good experiments" revealed the existence of the vector meson nonet, SU(3) breaking with singlet-octet mixing and the ...

CERN Document Server

Neutrinoless Double Beta Decay ($0\

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The authors report that the replacement of Leu-93 in bacteriorhodopsin by Ala (L93A) or Thr (L93T) slows down the photocycle by approximately 100-fold relative to wild-type bacteriorhodopsin. Time-resolved visible absorption spectroscopy and resonance Raman experiments, respectively, show the presence of long-lived O-like and N-like intermediates in the photocycles of the above mutants. We infer the existence of an equilibrium between the N and O intermediates in the photocycles of these mutants. The L93A and L93T mutants exhibit normal proton pumping under continuous illumination, suggesting that the decay of the N and/or O intermediate, and consequently, proton translocation, can be accelerated by the absorption of a second photon. Since the 13-cis----all-trans reisomerization of retinal is completed during the decay of the N and O intermediates, they conclude that the interaction of Leu-93 with retinal is important in ...

International Nuclear Information System (INIS)

Atomic oxygen is measured in a pulsed dielectric barrier discharge (DBD) using two-photon absorption laser-induced fluorescence (TALIF). The ground-level atomic oxygen is excited to the 3p "3P state by two-photon absorption at 226 nm. Negative (-40 kV) or positive (+30 kV) pulsed DBD occurs in an O_2-N_2 mixture at atmospheric pressure. The pulse width of the DBD current is approximately 50 ns. The TALIF experiment shows that the decay rate of atomic oxygen increases linearly with O_2 concentration. This result proves that atomic oxygen decays mainly by the third-body reaction, O + O_2 + M #-># O_3 + M. The rate coefficient of the third-body reaction is estimated to be 2.2 x 10"-"3"4 cm"6 s"-"1 in the negative DBD and 0.89 x 10"-"3"4 cm"6 s"-"1 in the positive DBD. It is shown that the decay rate of atomic oxygen increases linearly with humidity. This can explain the well-known fact that ozone ...

CERN Document Server

A search for the doubly charged Higgs boson, a member of $SU(2)_L$ scalar triplet $\\Phi$ participating in the seesaw mechanism of type II, in $pp$ collisions at $\\sqrt{s}=7$~TeV is presented. The data correspond to an integrated luminosity of 36 $\\text{pb}^{-1}$ collected by the CMS experiment at the LHC. The inclusive search is performed in events with three and four isolated charged leptons of all flavours originating from the decays of pair produced triplet components $\\Phi^{++}\\Phi^{--}$ and $\\Phi^{++}\\Phi^{-}.$ With the present collected luminosity the CMS experiment is sensitive to the $\\Phi$ mass range in which the possible decays $\\Phi^{++}\\to W^{+}W^{+}$ are forbidden kinematically. No signal excess is observed and lower limits at the 95\\% confidence level are set on the $\\Phi^{++}$ mass of 156\\GeV in the $\\mu\\mu$ channel, $154\\GeV$ in e$\\mu$ channel, of $144\\GeV$ in $ee$ ...

International Nuclear Information System (INIS)

Nuclear structure information for all nuclei with mass number A = 177 is summarized. Data from various decay and reaction experiments are compared. Evaluated data and the adopted spin, parity, and Nilsson--state assignments are given. Deviations from the regional trend of Nilsson ground-state assignments are noted for "1"7"7W and "1"7"7Re. Similar shifts have been observed in this region for nuclei 8 to 10 neutrons removed from the #beta#-stability line. In all cases, low-lying K/sup #pi#/ = 1/2/sup +-/ orbitals move to ground. Data received prior to February 1975 were included. (auth).

International Nuclear Information System (INIS)

The K_#beta#/K_#alpha# X-ray intensity ratios are measured for Mn and Fe and for six other elements with Z lying in the range 49<=Z<=82 following electron capture decay and photon excitation using "2"4"1Am and "5"7Co sources. High-resolution Si(Li) and HpGe detector systems were used in the experiments. The dependence of K_#beta#/K_#alpha# values on the mode of excitation in the case of Mn and Fe is attribuited to the chemical effects, while no such dependence is found for the high-Z elements.

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This study reports the observation of the decays B{sup 0}{yields}D{sup (*)+}{sub S}{pi}{sup -} and B{sup 0}{yields}D{sup (*)-}K{sup +} in a sample of 230 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring, located at the Stanford Linear Accelerator Center. The branching fractions {beta}(B{sup 0} {yields} D{sup +}{sub S}{pi}{sup -}) = (1.3 {+-} 0.3 (stat) {+-} 0.2 (syst)) x 10{sup -5}, {beta}(B{sup 0} {yields} D{sup +}{sub S}K{sup +}) = (2.5 {+-} 0.4 (stat) {+-} 0.4 (syst)) x 10{sup -5}, {beta}(B{sup 0}{yields}D{sup (*)+}{sub S}{pi}{sup -}) = (2.8 {+-} 0.6 (stat) {+-} 0.5 (syst)) x 10{sup -5}, and {beta}(B{sup 0}{yields}D{sup (*)-}K{sup +}) = (2.0 {+-} 0.5 (stat) {+-} 0.4 (syst)) x 10{sup -5} are measured. The significance of the measurements to differ from zero are 5, 9, 6, and 5 standard deviations, respectively. This is a first observation of the ...

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The central topic of this work is the study of the properties and the implementation of a Paul trap used for the measurement of the beta-neutrino angular correlation parameter in the decay of {sup 6}He. This coefficient provides a signature of the nature of the interactions involved in the weak interaction. The value of this coefficient can be deduced from the kinematical distribution of the decay events. An electromagnetic trap is used for the trapping of {sup 6}He{sup +} ions in a small volume. This trap has an open geometry that enables the detection in coincidence of the electron and the recoil ion emitted in the beta decay. A dedicated detection set up is used for the measurement of the electron energy, the ion time of flight and the position of the two particles for each event. A general description of the LPCTrap facility and of its performances is presented and shows that this set up is able to fulfill the proposed ...

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... coincidence spectrometry decay excited states gamma spectra half-life

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... beta decay coincidence spectrometry energy levels energy-level transitions

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The LHCb experiment that is being settled in CERN is dedicated to the study of CP violation and rare decays in the field of beauty hadrons. The phenomenological background necessary to an adequate understanding of the physics of flavor is presented in the first chapter, it is shown how the flavordynamics can open the way to new physics. The second chapter is dedicated to a brief presentation of the LHCb detector. Two aspects of the design of the muon trigger are more detailed: the radiation resistance of the opto-electronic transmitters and the simulated performances of the trigger. The third chapter reviews the tasks linked to the tagging of the savors of B mesons which will be an important step in all the experiments made at LHCb. The recent progress in heavy savor physics as well as the expected contribution of LHCb in this field are presented in the fourth chapter, especially the search for new physics in penguin ...

CERN Document Server

We study the sensitivity to neutrino masses of a Galactic supernova neutrino signal as could be measured with the detectors presently in operation and with future large volume water \\v{C}erencov and scintillator detectors. The analysis uses the full statistics of neutrino events. The method proposed uses the principles of Bayesian inference reasoning and has shown a remarkably independence of astrophysical assumptions. We show that, after accounting for the uncertainties in the detailed astrophysical description of the neutrino signal and taking into account the effects of neutrino oscillations in the supernova mantle, detectors presently in operation can have enough sensitivity to reveal a neutrino mass (or to set upper limits) at the level of 1 eV. This is sensibly better than present results from tritium $\\beta$-decay experiments, competitive with the most conservative limits from neutrinoless double $\\beta$-decay and ...

CERN Document Server

Using Zgamma candidate events collected by the CDF detector at the Tevatron Collider, we search for potential anomalous (non-standard-model) couplings between the Z boson and the photon. At the hard scatter energies typical of the Tevatron, standard model Zgamma couplings are too weak to be detected by current experiments; hence any evidence of couplings indicates new physics. Measurements are performed using data corresponding to an integrated luminosity of 4.9 /fb in the Z -> nunubar decay channel and 5.1 /fb in the Z -> l^+l^- (l=mu, e) decay channels. The combination of these measurements provides the most stringent limits to date on Zgamma trilinear gauge couplings. Using an energy scale of Lambda = 1.5 TeV to allow for a direct comparison with previous measurements, we find limits on the CP-conserving parameters that describe Zgamma couplings to be |h_3^{\\gamma,Z}| < 0.017 and |h_4^{\\gamma,Z}| < 0.0006. ...

International Nuclear Information System (INIS)

The nuclear power industry has experienced four carbon based adsorbent fires in its history, one was of the Monticello Standby Gas Treatment System and other three were in various off-gas delay beds. Although, some of the latter may not be classified as a full fledged fires. There were a number of experiments performed relating to igniting carbon beds and experiments relating to attempts at extinguishing set fires reported in the literature. Review of these experiments indicates that fire resulting from decay heat of adsorbed radioactive iodine is not justified even under the somewhat unrealistic source terms still in effect. At the same time the non-nuclear chemical industry application of carbon base adsorbents for solvent recovery has resulted in numerous fires and significant property losses. Fire control systems installed in nuclear air cleaning systems in the US consists of water deluge. ...

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The sub-criticality monitoring system has been developed for criticality safety control in nuclear fuel handling plants. In the past experiments performed with the Deuterium Critical Assembly (DCA), it was confirmed that the detection of sub-criticality was possible to k{sub eff} = 0.3. To investigate the applicability of the method to more generalized system, experiments were performed in the light-water-moderated system of the modified DCA core. From these experiments, it was confirmed that the prompt decay constant ({alpha}), which was a index of the sub-criticality, was detected between k{sub eff} = 0.623 and k{sub eff} = 0.870 and the difference of 0.05 - 0.1{Delta}k could be distinguished. The {alpha} values were numerically calculated with 2D transport code TWODANT and monte carlo code KENO V.a, and the results were compared with the measured values. The differences between calculated and ...

International Nuclear Information System (INIS)

The author calculated the wavefunctions and the energy-spectra of c bar c and b bar b bound systems using the Hamiltonian proposed by Gupta, Radford and Repko (GRR). He writes the GRR Hamiltonian as H = H_o + H', where H_o includes the kinetic energy terms and the most dominant terms in the Hamiltonian. H' includes among other things the spin-spin, spin-orbit and the tensor terms in the Hamiltonian. The eigenvalue problem of H_o is solved by the variational method which makes use of a trial wave-function with eleven parameters. H' is then treated in the first order perturbation theory. The energy-spectra agree very well with experimental data. He also calculated the E1 and the M1 decay rates of these quarkonia. With relativistic corrections, the E1 transitions agree better with experiment. The dominant relativistic correction comes from the relativistic modification of the wave-function. The M1 transitions can be improved by using a large quark ...

International Nuclear Information System (INIS)

The ALPHA project is centered around the experimental and analytical investigation of the long-term decay heat removal from the containments of the next generation of open-quotes passiveclose quotes ALWRs. The project includes integral system tests in the large-scale (1:25 in volume) PANDA facility as well as several other series of tests and supporting analytical work. The first series of experiments to be conducted in PANDA have become a required experimental element in the certification process for the General Electric Simplified Boiling Water Reactor (SBWR). The PANDA general experimental philosophy, facility design, scaling, and instrumentation are described. Steady-state PCCS condenser performance tests and extensive facility characterization tests were already conducted. The transient system behavior tests are underway; preliminary results from the first transient test M3 are reviewed.

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The optical spectroscopy measurements of gadolinium gallium garnet (GGG) crystals doped with Yb show evidence of the presence of non-equivalent optical centers with very similar radiative decay rates. The energy level schemes of those centers have been determined on the basis of optical absorption, luminescence and Raman experiments. Crystal field fitting resulted in two sets of slightly different crystal field parameters for two non-equivalent Yb centers. Both sets of parameters describe perfectly the experimentally detected Y b3+ energy levels. Correlation between systematic trends in the experimental energy level schemes and crystal field parameters is discussed.

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The theoretical formula for the statistical error estimation in Mihalczo method was derived, and the dependence of the error were investigated on the facility to be measured and on the parameter in the data analysis. The formula was derived based on the reactor noise theory and the error theory for the frequency analysis, and found that the error depends on such parameters as the prompt neutron decay constant, detector efficiencies, and the frequency bandwidth. Statistical errors estimated with the formula was compared with experimental values and verified to be reasonable. Through parameter surveys, it is found that there is an optimum combination of the parameters to reduce the magnitude of the errors. In the experiment performed in DCA subcriticality measurement facility, it is estimated experimentally that the measurement requires 20 minutes to obtain the statistic error of 1% for the keff 0.9. According to the error theory, this might be ...

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Decay heat removal capability under boiling condition was studied using an LMFBR fuel subassembly mockup loop. The sodium flow was driven by natural convection through the loop in which was installed a 37-pin bundle heated electrically over a length of 45 cm. The heat flux furnished by the pins was increased stepwise, upon which the two-phase flow regime changed from bubble to slug flow and then to annular or annular mist flow. Dryout occurred even in slug flow regime, but only momentarily, and permanent dryout was not observed before establichment of annular flow. A suitable criterion for permanent dryout is considered to be 0.5 average exit sodium vapor quality. The results indicated that upon occurrence of sodium boiling, the coolability of fuel subassembly would be maintained by natural convection after reactor shutdown. (author).

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The K/sub ..beta..//K/sub ..cap alpha../ X-ray intensity ratios are measured for Mn and Fe and for six other elements with Z lying in the range 49 less than or equal to Z less than or equal to 82 following electron capture decay and photon excitation using /sup 241/Am and /sup 57/Co sources. High-resolution Si(Li) and HpGe detector systems were used in the experiments. The dependence of K/sub ..beta..//K/sub ..cap alpha../ values on the mode of excitation in the case of Mn and Fe is attributed to chemical effects, while no such dependence is found for the high-Z elements.

International Nuclear Information System (INIS)

We briefly reviewed and summarized the experimental study on #beta#-delayed proton decays published by our group over the last 8 years, namely the experimental observation of #beta#-delayed proton decays of nine new nuclides in the rare-earth region near the proton drip line and five nuclides in the mass 90 region with N#approx#Z by utilizing the p-#gamma# coincidence technique in combination with a He-jet tape transport system. In addition, important technical details of the experiments were provided. The experimental results were compared to the theoretical predictions of some nuclear models, resulting in the following conclusions. (1) The experimental half-lives for "8"5Mo, "9"2Rh, as well as the predicted 'waiting point' nuclei "8"9Ru and "9"3Pd were 5-10 times longer than the macroscopic-microscopic model predictions of Moeller et al. [At. Data Nucl. Data Tables 66,131(1997)]. These data considerably influenced the ...

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... v. 33(4). beta-minus decay de-excitation delayed gamma radiation iron 64

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... Inst. of Modern Physics 7-5022-0983-2 180 p. beta decay ft value ground states

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The LSND (Liquid Scintillator Neutrino Detector) experiment will be performed at LAMPF in the next several years. The main goal of the experiment is to search for {nu}{sub {mu}}-{nu}{sub e} oscillations with high sensitivity; however, an increasingly important by-product of this search is to measure {nu}p {yields} {nu}p elastic scattering and determine the strange quark contribution, {Delta}s, to the spin of the proton. With the 800-MeV proton energy of LAMPF, neutrinos are produced from pion decay-in-flight with an average energy of about 150 MeV. This energy is sufficiently high so that the {nu}p {yields} {nu}p cross section is large and is sufficiently low so that the low Q{sup 2} approximation (Q{sup 2} {much lt} m{sub p}{sup 2}) is valid and the cross section can be expressed in a simple form dependent upon {Delta}s as the only unknown. LAMPF with its 1-mA proton intensity is, therefore, an ideal accelerator to perform ...

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Cementitious materials have physical and chemical properties that are well suited for the requirements of radioactive waste management. Namely, the materials have low permeability and durability that is consistent with the time frame required for short-lived radionuclides to decay. Furthermore, cementitious materials can provide a long-term chemical environment that substantially reduces the mobility of some long-lived radionuclides of concern for decommissioning (e.g., C-14, Ni-63, Ni-59). Because of these properties, cementitious materials are common in low-level radioactive waste disposal facilities throughout the world and are an attractive option for entombment of nuclear facilities. This paper describes design considerations for cementitious barriers in the context of performance over time frames of a few hundreds of years (directed toward short-lived radionuclides) and time frames of thousands of years (directed towards longer-lived radionuclides). The ...

International Nuclear Information System (INIS)

The 3 MW TRIGA Mark-II research reactor of Bangladesh Atomic Energy Commission (BAEC) has been operating since September 14, 1986. The reactor is used for radioisotope production ("1"3"1I, "9"9"mTc, "4"6Sc), various R and D activities and manpower training. The reactor has been operated successfully since it's commissioning with the exception of a few reportable incidents. Of these, the decay tank leakage incident of 1997 is considered to be the most significant one. As a result of this incident, reactor operation at full power under forced-convection mode remained suspended for about 4 years. During that time, the reactor was operated at a power level of 250 kW so as to carry out experiments that require lower neutron flux. This was made possible by establishing a temporary by pass connection across the decay tank using local technology. The other incident was the contamination of the Dry Central Thimble (DCT) that took ...

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... beta spectrometers decay energy-level transitions k conversion l conversion

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Short communication

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This two-volume reference uses many equations to provide detailed information on atomic and nuclear decay phenomena.

International Nuclear Information System (INIS)

The FFTF is a 400-MWt sodium-cooled fast neutron flux test reactor located on the US government-owned Hanford Site in southeastern Washington state. The reactor is operated for the US Department of Energy by the Westinghouse Hanford Company. Since FFTF started routine operation in 1982, the commercially fabricated driver fuel has performed flawlessly to well beyond the design goal peak burnup of 80 MWd/kgM. The core average discharge exposure is now some 60% beyond the original design expectations and attests to the ruggedness and reliability of the mixed oxide fuel system. In Cycle 9 sixteen long-life assemblies were installed to begin the irradiation of mixed oxides in the advanced low-swelling alloy HT-9 as the Core Demonstration Experiment (CDE). Operation of the plant from initial startup testing to ten cycles of operation has confirmed that the nuclear characteristics are well within the design predictions, and all parameters have remained inside the ...

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Transient Enhanced Diffusion (TED) of dopants in Si is the consequence of the evolution, upon annealing, of a large supersaturation of Si self-interstitial atoms left after ion bombardment. In the case of amorphizing implants, this supersaturation is located just beneath the c/a interface and evolves through the nucleation and growth of End-Of-Range (EOR) defects. For this reason, the authors discuss here the relation between TED and EOR defects. Modelling of the behavior of these defects upon annealing allows one to understand why and how they affect dopant diffusion. This is possible through the development of the Ostwald ripening theory applied to extrinsic dislocation loops. This theory is shown to be readily able to quantitatively describe the evolution of the defect population (density, size) upon annealing and gives access to the variations of the mean supersaturation of Si self-interstitial atoms between the loops and responsible for TED. This initial supersaturation is, before ...

Science.gov (United States)

Over the recent years the nuclear structure around the N = 50 shell closure, which is very pronounced in the strontium and zirconium isotopes, has been the subject of extensive experimental and theoretical work. On the proton side Z = 38 and Z = 40 provide fairly closed sub-shells. In the strontium isotopes the lg/sub 9/2/ neutron shell is closed at /sup 88/Sr, supplying relatively pure neutron-hole and neutron-particle states with large spectroscopic factors in /sup 87/Sr and /sup 89/Sr, as well as core-coupled states. The mass region is thus ideally suited to examine the transition from a correlated to an uncorrelated (chaotic.) excitational behavior. These two types are characterized e.g. by the density of excited states, the transition strengths, and the spectroscopic factors observed in transfer reactions. We conducted (n,..gamma..) and (d,p) reactions leading to /sup 87,88,89/Sr in addition to /sup 88/Sr(d,t)/sup 87/Sr and 24 keV neutron capture in /sup 88/Sr. The vast amounts of ...

International Nuclear Information System (INIS)

Three resonances at the proton energies 7.0, 7.08, and 7.53 MeV on the target "8"8Sr were chosen to investigate the possibility of determining the amplitudes of the weak coupling experimentally. The corresponding "8"9Sr levels under investigation were 1.93 MeV ("5/_2"+), 2.00 MeV ("3/_2"+), and 2.46 MeV ("3/_2"+). Angular distributions were measured on resonance at 7.0, 7.08, and 7.53 MeV from proton inelastic scattering to the 1.84 MeV (2"+) state of "8"8Sr for differential cross section, analyzing power, spin-flip probability, and spin-flip asymmetry. A polarized beam of protons was used to obtain the analyzing power. The spin-flip probability was obtained from the coincidence of the prompt gamma rays from the (p,p'#gamma#) reaction with the scattered protons. With the polarized beam, the gamma coincidence technique was further used to obtain a spin-flip asymmetry measurement. From these measurements, the polarization was calculated, and the first clear experimental examples of the ...

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Spin-polarized liquid helium-3 is prepared by laser optical pumping in low magnetic field and at room temperature, prior to fast liquefaction of the polarized sample. The use of a new helium-3 cryostat enabled us to obtain liquid helium-3 with polarization rates up to 25 % at well-stabilized temperatures (around 0.5 K). We could thereby study the effect of nuclear polarization on liquid-vapour equilibrium, and particularly on the saturated vapour pressure. Very sensitive capacitive gauges were developed. We estimated (to first order in M{sup 2}) the expected effects when the polarization M is suddenly destroyed. These effects were experimentally observed in helium-3/helium-4 mixtures, in pure helium-3, only a transient increase in pressure has been recorded. We then describe in a third part a preliminary experiment which aimed at determining the longitudinal relaxation time T1 in mixtures. Relaxation on the walls is efficiently reduced by a cesium coating and T1s ...

CERN Document Server

We propose to investigate the in-medium properties of vector $\\omega$ mesons at the normal nuclear density in Ap(pA) collisions and at higher density in AA collisions at the ITEP accelerator facility TWAC. Using of the inverse Ap kinematics will permit us to study the $\\omega$ meson production in a wide momentum interval included the not yet explored range of small meson momenta relative to the projectile nuclei where the mass modification effect in nuclear matter is expected to be the strongest. Momentum dependence of the in-medium $\\omega$ meson width will be studied in the traditional pA kinematics. We intend to use the electromagnetic calorimeter for reconstruction of the $\\omega$ meson invariant mass by detecting photons from the $\\omega \\to \\pi^{0}\\gamma \\to 3\\gamma$ decay. The model calculations and simulations with RQMD generator show feasibility of the proposed experiment. Available now intensity of the ion beams provides a ...

CERN Document Server

The presented results are the first measurements at RHIC for direct $\\gamma$-charged hadron azimuthal correlations in heavy ion collisions. We use these correlations to study the color charge density of the medium through the medium-induced modification of high-p$_T$ parton fragmentation. Azimuthal correlations of direct photons at high transverse energy (8 $<$ p$_T$ $<$ 16 GeV) with away-side charged hadrons of transverse momentum (3 $<$ p$_T$ $<$ 6 GeV/c) have been measured over a broad range of centrality for $Au+Au$ collisions and $p+p$ collisions at $\\sqrt{s_{NN}}$ = 200 GeV in the STAR experiment. A transverse shower shape analysis in the STAR Barrel Electromagnetic Calorimeter Shower Maximum Detector is used to discriminate between the direct photons and photons from the decays of high p$_T$ $\\pi^{0}$. The per-trigger away-side yield of direct $\\gamma$ is smaller than from $\\pi^{0}$ trigger at the same centrality class. ...

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We examine the virtual effects of Kaluza-Klein (KK) states on Higgs physics in universal extra dimension models. We study the partial widths {Lambda}{sub h{yields}gg}, {Lambda}{sub h{yields}{gamma}{gamma}}, and {Lambda}{sub h{yields}{gamma}Z}, which are relevant for Higgs production and detection in future collider experiments. These interactions occur at one loop in the Standard Model, as do the KK contributions. We find that the deviations induced by the KK exchanges can be significant; for one extra dimension, the gg {yields} h production rate is increased by 10% - 85% for the mass of the first KK state in the range 500 {approx}> m{sub 1} {approx}> 1500 GeV, a region untested by current direct search and precision measurement constraints. The h {yields} {gamma}{gamma} decay width is decreased by {approx}< 20% in the same mass range. For two or more universal extra dimensions the results are cutoff dependent, and can only ...

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Rotationally resolved spectra of kinetic energy releases epsilon-c in predissociations of H/sub 2/, after dissociative charge exchange of H/sub 2/ /sup +/ with Cs atoms, are obtained. The experiments are performed with natural and with pure parahydrogen. The predissociations with epsilon-c<1.9 eV constitute less than 5% of the total amount of dissociations to HXchemically bondH at a beam energy of 5 keV. All strong rotational peaks observed could be attributed to n = 3 Rydberg states which predissociate to H(1s)+H(2l). Vibrational-rotational series are observed of the d /sup 3/Pi/sub u//sup +/, D /sup 1/Pi/sub u//sup +/, and J /sup 1/..delta../sub g//sup +/ states. Predissociation by barrier tunneling is reported of v = 4 levels of the h /sup 3/..sigma../sub g//sup +/ state and of v = 4 and 5 levels of the i /sup 3/Pi/sub g/ state. Selectivity of the charge-exchange process for different n = 3 states, or even for different parity states, is concluded.

CERN Document Server

We conjecture that all CP violations (both Dirac and Majorana types) arise from a common origin in neutrino seesaw. With this conceptually attractive and simple conjecture, we deduce that mu-tau breaking shares the common origin with all CP violations. We study the common origin of mu-tau and CP breaking in the Dirac mass matrix of seesaw Lagrangian (with right-handed neutrinos being mu-tau blind), which uniquely leads to inverted mass-ordering of light neutrinos. We then predict different correlations between the two small mu-tau breaking observables theta_{13} - 0 and theta_{23} -45, which can be tested against our previous normal mass-ordering scheme by the on-going oscillation experiments. We also analyze the correlations of theta_{13} with Jarlskog invariant and neutrinoless double-beta-decay observable. From the common origin of CP and mu-tau breaking in the neutrino seesaw, we establish a direct link between the low energy CP violations ...

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This dissertation describes a measurement of the rate ofnuclear muon capture by the proton, performed by the MuCap Collaborationusing a new technique based on a time projection chamber operating inultraclean, deuterium-depleted hydrogen gas at room temperature and 1 MPapressure. The hydrogen target's low gas density of 1 percent compared toliquid hydrogen is key to avoiding uncertainties that arise from theformation of muonic molecules. The capture rate was obtained from thedifference between the mu- disappearance rate in hydrogen--as determinedfrom data collected in the experiment's first physics run in fall2004--and the world averagefor the mu+ decay rate. After combining theresults of my analysis with the results from another independent analysisof the 2004 data, the muon capture rate from the hyperfine singlet groundstate of the mu-p atom is found to be Lambda_S = 725.0 +- 17.4 1/s, fromwhich the induced pseudoscalar ...

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The young open cluster Berkeley 87 was predicted to be associated with the COS B {gamma}-ray source 2CG 075+00 on the basis of the experimental evidence of the presence of a shock front around the Wolf - Rayet star ST3 placed in the inner part of the cluster. The CGRO phase-1 data confirm this identification. Protons accelerated at the shock boundary can produce {pi} deg. via p-p interactions and then {gamma}-rays. With the measured flux F{sub {gamma}} (E > 100 MeV) {approx_equal} 9x10{sup -7} ph cm{sup -2} s{sup -1} and the power-law proton spectrum with spectral index {gamma} = 2, the cosmic-ray-energy-density in the inner part ({approx} 0.8 pc radius) of Berk 87 is about 100 times greater than that in the vicinity of the Earth. We have calculated {gamma}-ray spectra expected from the decay of {pi}{sup d}eg. produced in p-p interactions. The spectra have been normalized to the observed flux of Berk 87 by using different input proton spectra. The comparison ...

International Nuclear Information System (INIS)

The understanding of fission product deposition in realistic steam generator conditions is needed for release estimates in PSA studies, and for the design of efficient accident management procedures. This is considered very important because primary-to-secondary leakages risk dominant sequences in many plants. Furthermore, the decay heat of the fission product deposits adds to the thermal load to the steam generator tubes also in other sequences, especially in case of cold leg leakages. This brings out the concern of induced steam generator tube ruptures in cases, where the steam generators are initially intact. The experimental data showed that the highest deposited fraction within the tubes were found in cases with lowest flow velocities. The minimum value of the deposited fraction was observed at intermediate flow velocities. With these relatively low Reynolds numbers, the results calculated with deposition models agree well with the ...

CERN Document Server

beta- and gamma-decay studies of neutron-rich chromium, manganese, cobalt and nickel isotopes including the new isotopes $^{60}$Cr and $^{60g}$Mn

International Nuclear Information System (INIS)

The radioactive decay of "2"0"3Bi is studied. A level scheme is proposed for "2"0"3Pb on the basis of #gamma#-ray and electron spectra and #gamma#-#gamma# coincidence measurements. The experimental data are compared with theoretical results obtained in a three quasiparticle approximation. (Auth.).

International Nuclear Information System (INIS)

Detailed level and decay schemes and the experimental reaction and decay data on which they are based are presented for nuclei with mass number A = 242; the experimental data are evaluated. Adopted values for level and #gamma#-ray energies, #gamma#-intensities, as well as other nuclear properties are given.

British Library Electronic Table of Contents (United Kingdom)

This paper introduces briefly neutrinoless Double Beta Decay and discusses its implications for neutrino physics. After a presentation of general experimental concepts, such as the various proposed methodological approaches and the sensitivity, the current experimental situation is concisely reviewed.

International Nuclear Information System (INIS)

... bismuth 203 chemical reactions cyclotrons decay helium 3 beams impurities

Science.gov (United States)

It is shown that there may be a correlation between the galactic cosmic rays and the solar neutrino

International Nuclear Information System (INIS)

The measurements of the nuclear decay of actinide isotopes and the evaluation of the radioactive properties of nuclide with the mass 242 is discussed in this paper.

International Nuclear Information System (INIS)

... comparative evaluations energy-level transitions half-life internal conversion

CERN Document Server

The absolute branching fractions for the decays $D^0 \\to K^-e ^+\

International Nuclear Information System (INIS)

Gamma-rays and conversion electrons emitted in the "1"1"7Cs and "1"1"7Xe decays have been studied from on-line mass-separated "1"1"7Cs sources at the ISOLDE facility. A new "1"1"7Xe decay scheme has been constructed and a level scheme has been established for the "1"1"7Cs decay. The results are discussed in the frame of our recent knowledge about odd-mass neutron-deficient I and Xe systematics.

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... angiotensin gallium 67 lungs lysozyme patients sarcomas beta decay

International Nuclear Information System (INIS)

The nucleon decay of subbarrier single-particle states with large angular momentum and parity opposite to that of the shell in soft spherical nuclei is considered. It is shown that the reduced probabilities of the nucleon decay into the ground state (0"+) and into the first excited (2"+) state of the daughter nucleus have qualitatively different energy dependences. (orig.).

Energy Technology Data Exchange (ETDEWEB)

New measurements of relative gamma-ray emission probabilities in the decay of [sup 101]Mo and [sup 101]Tc are reported. Previously published conversion-electron data have been used along with the gamma-ray data to formulate self-consistent decay schemes. (orig.)

CERN Document Server

The Daya Bay reactor neutrino experiment

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Fermilab experiment E791 took data during six months in 1991 using a 500 GeV {pi}{sup -} beam on platinum and diamond targets for the purpose of studying the production and decay of particles containing a charm quark. In this dissertation, results are presented on the production of the D{sup 0} and {anti D}{sup 0} mesons using fully reconstructed D{sup 0}{yields}K{pi} and D{sup 0}{yields}K{pi}{pi}{pi} decays. Specifically, the total forward production cross section is measured as well as differential cross sections as a function of the scaled longitudinal momentum, Feynman-x (x{sub F}), and the transverse momentum squared (p{sub T}{sup 2}). The results are compared to theoretical predictions from a next-to-leading order (NLO) calculation and from a leading order Monte Carlo event generator, PYTHIA/JETSET, which uses parton showers to account for higher-order terms. The comparison is made to both the c quark predictions and ...

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Residual plutonium (Pu), with trace quantities of depleted uranium (DU) or weapons grade uranium (WU), exists in surficial soils at the Nevada Test Site (NTS), Nellis Air Force Range (NAFR), and the Tonopah Test Range (TTR) as the result of the above-ground testing of nuclear weapons and special experiments involving the detonation of plutonium-bearing devices. The special experiments (referred to as safety shots) involving plutonium-bearing devices were conducted to study the behavior of Pu as it was being explosively compressed; ensure that the accidental detonation of the chemical explosive in a production weapon would not result in criticality; evaluate the ability of personnel to manage large-scale Pu dispersal accidents; and develop criteria for transportation and storage of nuclear weapons. These sites do not pose a health threat to either workers or the general public because they are under active institutional control. The DOE is ...

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The activation aspects of pure fusion and hybrid fusion technology is studied to assess the radioactive safety of various fusion concepts including tokamak pure fusion, fissile fuel producing hybrid and radio waste transmuting hybrid. The activation properties of breeding, coolant and structural materials in fusion reactors might be quite different from those in fission reactors because of the high energy D-T fusion neutrons from the fusion cores. A study on the involved activation reactions and the uncertainties of the associated nuclear cross-sections is carried. The activation properties of various first wall concepts and blanket concepts are discussed. The radioactive inventory during the operation lifetime and the potential hazard of the radioactive nuclides with respect to near term (reprocessing) and long term (waste disposal) aspects are calculated, with reference to ITER/NET (International Thermonuclear Experiment Reactor/Next European Torus), STARFIRE (a ...

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The current status of rare B decays is reviewed based on recent observation of the penguin-diagram decay B {yields} K{sup *}{gamma} at CLEO. Rare B decays provide valuable information on the Standard Model parameters, and also could be a source of direct CP violation. It is emphasized that new physics beyond the Standard Model can appear in rare B decays, in some cases more drastically than in the CP Asymmetry of the B system. Inclusive measurement of the radiative transition b {yields} s{gamma} is promising. Hadronic penguin modes are very close to being observed at CLEO, and a discovery might be just around the corner. (author). 48 refs., 6 figs., 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

Proton and alpha decay from the giant resonance region of {sup 28}Si excited with a 129 MeV alpha particle beam has been measured in coincidence with inelastic alpha particles detected at 0{degree}. The angular correlation data show the presence of decay from both {ital E}0 and {ital E}2 giant resonances. The {ital E}0 giant resonance decays primarily through the {alpha}{sub 0}, {alpha}{sub 1}, {ital p}{sub 0}, and {ital p}{sub 1,2} channels with the branching ratios 18{plus minus}6 %, 24{plus minus}8 %, 23{plus minus}9 %, and 18{plus minus}8 %, respectively. Substantial direct decay is observed.

International Nuclear Information System (INIS)

The study of B#->##tau#"+#tau#"-(X) decays can provide us with a better understanding of the third generation, and can be a useful probe of physics beyond the standard model. We present a model-independent analysis of these decays. We classify new physics that can largely enhance the decay rates and we discuss the constraints implied by other processes. Experimentally, flavor-changing neutral current B decays into final state #tau# close-quote s are still unconstrained. Searches for B decays with large missing energy at CERN LEP provide the first limits. We estimate that existing data already imply bounds on the B_d#->##tau#"+#tau#"-, B_s#->##tau#"+#tau#"-, and B#->#X#tau#"+#tau#"- decay rates at the few percent level. Although these bounds are over four orders of magnitude above the standard model predictions, they provide the first constraints on ...

Energy Technology Data Exchange (ETDEWEB)

The MiniBooNE experiment [1] is motivated by the LSND observation, [2] which has been interpreted as {nu}{sub {mu}} {yields} {nu}{sub e} oscillations, and by the atmospheric neutrino deficit, [3,4,5] which may be ascribed to {nu}{sub {mu}} oscillations into another type of neutrino. MiniBooNE is a single-detector experiment designed to: obtain {approx} 1000 {nu}{sub {mu}} {yields} {nu}{sub e} events if the LSND signal is due to {nu}{sub {mu}} {yields} {nu}{sub e} oscillations, establishing the oscillation signal at the > 5{sigma} level as shown in Fig. 1.1; extend the search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations significantly beyond what has been studied previously if no signal is observed; search for {nu}{sub {mu}} disappearance to address the atmospheric neutrino deficit with a signal that is a suppression of the rate of {nu}{sub {mu}}C {yields} {mu}N events from the expected 600,000 per year; measure the oscillation ...

International Nuclear Information System (INIS)

Decay sequences based on the 1/2"+[660] proton orbital have been identified in "1"7"1Ta and "1"7"7Re based on spin, parity, and large alignment. This decay sequence is observed higher in energy than predicted in cranking calculations based on modified oscillator potentials. Similarly known 1/2"-[541] decay sequences in these and other neighbouring isotopes are observed lower in energy than predicted. A reduction in the strength of the spin-orbit potential for protons is suggested as a solution to these problem. (orig.).

CERN Document Server

The Dalitz plot of $\\eta^{\\prime} \\to \\eta \\pi^+ \\pi^-$ decay is studied using $(225.2\\pm2.8)\\times 10^6$ $\\jpsi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider. With the largest sample of $\\eta^{\\prime}$ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also the branching fraction of $\\jpsi \\to \\gamma \\eta^{\\prime}$ is determined to be $(4.84\\pm0.03\\pm0.24)\\times 10^{-3}$, where the first error is statistical and the second systematic.

CERN Document Server

The recent measurements by the BES Collaboration of J/psi decays into a photon and a proton-antiproton pair indicate a strong enhancement at the proton-antiproton threshold not observed in the decays into a neutral pion and a proton-antiproton pair. Is this enhancement due to a proton-antiproton quasi-bound state or a baryonium? A natural explanation follows from a traditional model of proton-antiproton interactions based on G-parity transformation. The observed proton-antiproton structure is due to a strong attraction in the 1S0 state, and possibly to a near-threshold quasi-bound state in the 11S0 wave.

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The theory of ..cap alpha.. decay in first-order perturbation theory is presented. The theory is designed for a strongly deformed nucleus in an isomeric state which changes its deformation dynamically through decay from a very deformed to an almost spherical shape. It is shown that other channels are not coupled to the ..cap alpha.. channel in first-order perturbation theory. The collective degrees of freedom of the daughter nucleus are described by shape vibrational states, eigenstates of a Hamiltonian whose potential has two minima. The parent nucleus is described by dynamically coupling the vibrational degrees of freedom to the ..cap alpha..-particle motion and also taking rotations into account. The ..cap alpha.. particle is taken to be a point-like particle. The theory is applied to the ..cap alpha.. decay of the isomeric state of /sub 95//sup 242/Am.

International Nuclear Information System (INIS)

German 2001 p. 253-258 Germany Hages, P. Stratmann, W. STEAG encotec

International Nuclear Information System (INIS)

The decay of mass-separated samples of the previously unknown nuclide "7"1Br have been investigated by means of the Chalk River on-line isotope separator. Eleven #gamma#-transitions were assigned to the decay of this nuclide and its half-life was measured to be 21.4 +- 0.6 s. A simple decay scheme for "7"1Br has been constructed incorporating six levels in its daughter, "7"1Se. The half-life of the first excited state in "7"1Se was measured to be 5.5 +- 1.0 #mu#s and the transition from this state to the ground state was found to be highly converted. Systematic trends in the level schemes of "6"7Zn, "6"9Ge and "7"1Se are investigated. (orig.).

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In April and May of 1999 the Berkeley Gas-filled Separator was used to search for the production and decay of element 118 from the {sup 86}Kr + {sup 208}Pb reaction, according to Smolanczuk's predictions of relatively large production rates. Three decay chains, each consisting of an implanted heavy ion, followed by a rapid (ms) succession of high-energy (>10 MeV) alpha-particle decays were detected. These chains are consistent with the production and decay of element 118 with mass number 293. These results a) show experimental evidence for the existence of shell-stabilized superheavy elements, b) provide experimental values for refinement of nuclear mass models in the superheavy element region, and, most importantly, c) present a new' reaction pathway for the production of superheavy elements. (author)

CERN Document Server

We report a measurement of the branching fractions for $B^{0} \\rightarrow \\pi^- \\ell^+\

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The authors present the results of a search for W{prime} boson decaying to electron-neutrino pairs in p{bar p} collisions at a center-of-mass energy of 1.96 TeV, using a data sample corresponding to 205 pb{sup -1} of integrated luminosity collected by the CDF II detector at Fermilab. They observe no evidence for this decay mode and set limits on the production cross section times branching fraction, assuming the neutrinos from W{prime} boson decays to be light. If they assume the manifest left-right symmetric model, they exclude a W{prime} boson with mass less than 788 GeV/c{sup 2} at the 95% confidence level.

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We study CP-violating phenomena in the production, mixing and decay of a coupled system of CP-violating neutral Higgs bosons at {gamma}{gamma} colliders, assuming a Minimal Supersymmetric Standard Model (MSSM) Higgs sector in which CP violation is radiatively induced by phases in the soft supersymmetry-breaking gaugino masses and third-generation trilinear squark couplings. We discuss CP asymmetries in the production and decays of {mu}{sup +}{mu}{sup -}, {tau}{sup +}{tau}{sup -}, b-bar b and t-bar t pairs. We find large asymmetries when two (or all three) neutral Higgs bosons are nearly degenerate with mass differences comparable to their decay widths, as happens naturally in the CP-violating MSSM for values of tan{beta}-bar 5 (30) and large (small) charged Higgs-boson masses.

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The estimation of radiation dose to man from either external or internal exposure to radionuclides requires a knowledge of the energies and intensities of the atomic and nuclear radiations emitted during the radioactive decay process. The availability of evaluated decay data for the large number of radionuclides of interest is thus of fundamental importance for radiation dosimetry. This handbook contains a compilation of decay data for approximately 500 radionuclides. These data constitute an evaluated data file constructed for use in the radiological assessment activities of the Technology Assessments Section of the Health and Safety Research Division at Oak Ridge National Laboratory. The radionuclides selected for this handbook include those occurring naturally in the environment, those of potential importance in routine or accidental releases from the nuclear fuel cycle, those of current interest in nuclear medicine and ...

International Nuclear Information System (INIS)

The available nuclear structure information for all nuclei with mass number A=242 is presented. Various decay and reaction data are evaluated. Adopted data, levels, spin and parity assignments are given.

International Nuclear Information System (INIS)

... ground states iridium 187 iridium 189 beta decay radioisotopes days living

International Nuclear Information System (INIS)

... band theory excited states iridium 187 iridium 189 beta decay radioisotopes

International Nuclear Information System (INIS)

24 isotopes of astatine element 85, are known today, three of which occur naturally as decay products of "2"1"5U and "2"5"8U, respectively. Because these isotopes being very short-lived, all experiments dealing with this heaviest element of the halogen group need be done with "2"0"9"-"2"1"1At, having half-lifes in the several hours region. Mixtures of them may be obtained either by #alpha#-bombardment (E#alpha# approximately 30-50 MeV) of "2"0"9Bi or as spallation products by the reaction of high-energy protons with thorium and uranium targets. - In its chemical reactions astatine shows a behaviour which is between an halogen and a metal. The following oxidation states have been shown to exist: -1, 0, +1, +5 and +7. At"-, AtO_2"- and AtO_4"- are the ionic species for At(-I), At(+V) and At(+VII) whereas no definite species have been established for the other oxidation states. Furthermore, At_2 could not be shown to exist as yet in contrast to ...

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Radioisotopes of Pb(II) have been of some interest in radioimmunotherapy and radioimmunoimaging (RII). However, the absence of a kinetically stable bifunctional chelating agent for Pb(II) has hampered its use for these applications. {sup 203}Pb (T{sub 1/2}=52.02 h) has application potential in RII, with a {gamma}-emission that is ideal for single photon emission computerized tomography, whereas {sup 212}Pb (T{sub 1/2}=10 h) is a source of highly cytotoxic {alpha}-particles via its decay to its {sup 212}Bi (T{sub 1/2}=60 min) daughter. The synthesis of the novel bifunctional chelating agent 2-(4-isothiocyanotobenzyl)-1,4,7,10-tetraaza-1,4,7,10-tetra-(2-carbamoyl methyl)-cyclododecane (4-NCS-Bz-TCMC) is reported herein. The Pb[TCMC]{sup 2+} complex was less labile to metal ion release than Pb[DOTA]{sup 2-} at pH 3.5 and below in isotopic exchange experiments. In addition to increased stability to Pb{sup 2+} ion release at low pH, the bifunctional ...

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In the invar alloy (Fe{sub 0.65}Ni{sub 0.35}){sub 1-} {sub x} Mn {sub x} we measured the magnetic form factor s(Q) and the intermediate scattering function s(Q,t) for a sample close to the critical Mn concentration (x {sub c}=0.139), at which the sample turns to a re-entrant spin glass phase. The aim was to check whether the magnetic behaviour would approach the Q-independent relaxation behaviour of a classical spin glass when x=x {sub c}. The experiment showed a quite similar spin freezing as for a more ferromagnetic sample with x=0.113. The intermediate scattering function and the form factor were determined by paramagnetic NSE. The normalized scattering function S(Q,t)=s(Q,t)/s(Q)=exp[(-{gamma}t) {sup n}] was fitted by stretched exponential decay. As a function of temperature T<200 K the inverse time constant {gamma} showed the change of more than four orders of magnitude from frozen spin glass (T=60 K to T=100 K), where the ...

International Nuclear Information System (INIS)

Precise measurements of alpha particle counting efficiencies have been made using isotropic, infinitely thin alpha emitting sources placed in direct contact with a thin, end-window, gas flow proportional detector. Except for alpha particle absorption in the window material, this geometry approaches 2#pi#, such that the only other variation in the response of the counter is from the random decay of the source. The data are fitted to the expected linear function of count rate versus window thickness and the resulting fitting parameters are used to calculate the counting efficiencies for a given thickness of window material. Counting efficiencies for 5.31, 6.06, and 8,78 MeV alpha particles have been determined from sources of "2"1"0Po and the progeny of "2"1"2Pb. For the particular counter used, the counting efficiencies in counts per alpha and their respective relative standard deviations were 0.401 #+-# 0.12%, 0.418 #+-# 0.41%, and 0.455 #+-# 0.10%. The isotropic, ...

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Synthetic zeolite of 0.5 nm pore size (5A) and blue silica gel were tested to determine their capability to be used as radon collectors. Tests conducted in a radon chamber under controlled conditions of temperature and relative humidity indicate that simple, inexpensive and maintenance-free passive devices containing about 250 g of synthetic zeolite or about 270 g of blue silica gel in open face metal canisters that can measure radon conveniently and adequately, the latter though being suitable only for dry-medium dry atmosphere with quite high radon concentrations. Both materials can be recycled for reuse, in a way similar to the recycle and reuse of active carbon. The amount of radon adsorbed in such collectors is determined by counting the gamma rays from the radon decay products. The lower limit of detection (LLD) is estimated to {approx}45 Bqm{sup -3} for the synthetic zeolite and to {approx}350 Bqm{sup -3} for the blue silica gel, for an exposure of 48 h at a ...

Energy Technology Data Exchange (ETDEWEB)

'Improvement in understanding of the deposition of ambient dust particles on ECAM (Environmental Continuous Air Monitor) filters, reduction of the alpha-particle interference of radon progeny and other radioactive aerosols in different particle size ranges on filters, and development of ECAM''s with increased sensitivity under dusty outdoor conditions. As of May 1, 1998 (1/2 year into the project) the research-prototype 30-cm pulsed ionization chamber (PIC) is assembled and operational with an alpha particle energy resolution of better than 45 keV for 5-MeV alpha particles. Measurements of spectral resolution for alpha particles from radon decay products have been made as a function of filter type and dust loading conditions. So far, a study of ten filter types has found that the best combination of resolution and throughput is obtained with 3.0 \\265m Millipore fluoropore and 1.0 \\265m Corning FNMB filters. ...

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A Bianchi type-IX cosmological model has been found as a solution of Einstien's vacuum field equations with a cosmological constant. The solution represents a rotating generalziation fo the de Sitter universe. This universe shows a transition to exponential expansion and the vorticity begins to decay exponentially at the grand-unified-theory time. The point of time for this transition is independent of the magnitude of the vorticity. During the Guth inflationary era the vorticity decays by a factor of the order 10 US.

International Nuclear Information System (INIS)

A new channel of nonlinear ionization of quantum system in a strong laser field is discussed. The probability of spontaneous radiation decay from the ground state in a short-range potential to the final Volkov wave function, is calculated by the first order of the perturbation theory. It is shown that this process at high intensities of the laser field will be comparable with the high harmonic generation. (orig.)

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The lowest excited level in Ni-like ions, 3d{sup 9}4s {sup 3}D{sub 3}, decays only via a magnetic octupole (M3) decay. They present calculated values of transition wavelengths and rates for ions with 30 {le} Z {le} 100. They have observed this line in Xe{sup 26+}, using the Livermore EBIT-I electron beam ion trap and a microcalorimeter, as well as a high-resolution flat-field grating spectrometer.

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We use a nonsingular-potential model for heavy quarkonia proposed by Gupta, Repko, and Suchyta to calculate the transition amplitudes for the magnetic-dipole ({ital M}1) one-photon radiative decays of the {ital c{bar c}} and {ital b{bar b}} bound systems. The wave functions of the bound systems are calculated by a nonperturbative treatment. The results are in better agreement with the experimental data than those predicted using other potential models.

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In our previous theoretical analyses, solubility-limited mass transfer from waste solids applies if a species is at a constant elemental concentration in liquid at the waste surface. For an element with isotopes that decay appreciably during the time of interest, a solubility boundary condition results in a time-dependent boundary concentration of each isotope. Here we present mass-transfer equations that include the effects of isotopic decay boundary conditions. 9 refs., 1 fig.

International Nuclear Information System (INIS)

The status of Monte Carlo system for the simulation of Bremsstrahlung in arbitrary decays and for the decay itself of #tau# -lepton is reviewed. During the last #tau# -lepton conference in 2010 several developments of the last two years have been presented: (i) For the TAUOLA Monte Carlo generator of #tau# -lepton decays, automated and simultaneous use of many versions of form-factors for the calculation of optional weights for fits was developed and checked to work in Belle and BaBar software environment. On-going work on alternative parameterizations of hadronic decays is presented too. (ii) The TAUOLA universal interface based on HepMC (the C++ event record) is now public. A similar interface for PHOTOS is now also public. (iii) Extension of PHOTOS Monte Carlo for QED Bremsstrahlung in decays featuring kernels based on complete first order matrix element are gradually becoming ...

Science.gov (United States)

The Interim Decay Storage tank (IDS) will be located in a concrete cell in the FFTF reactor building. The tank will have capacity to store 112 driver fuel assemblies and 10 test assemblies in sodium. A criticality safety analysis for the design of the IDS tank was performed. From the analysis, it is concluded that under normal operating conditions and minor abnormal conditions that might shift the fuel, the IDS tank will remain adequately subcritical. (auth)

International Nuclear Information System (INIS)

The #beta# decay half-lives of neutron-rich isotopes with Z=24-28 are calculated in the QRPA with a Gamow-Teller residual interaction. For odd-mass and odd-odd systems QRPA phonon correlations are introduced to quasiparticle transitions in first-order perturbation. The calculated half-lives agree very well with the experimental values. For later application of this model to nuclei far from stability, we have examined the dependence of the calculated half-lives on the model parameters. (orig.).

CERN Document Server

Recently PAMELA released their first results on the positron and antiproton ratios. Stimulated by the new data, we studied the cosmic ray propagation models and calculated the secondary positron and antiproton spectra. The low energy positron ratio can be consistent with data in the convection propagation model. Above $\\sim 10$ GeV PAMELA data shows a clear excess on the positron ratio. However, the secondary antiproton is roughly consistent with data. The positron excess may be a direct evidence of dark matter annihilation or decay. We compare the positron and anti-proton spectra with data by assuming dark matter annihilates or decays into different final states. The PAMELA data actually excludes quark pairs being the main final states, disfavors gauge boson final states. Only in the case of leptonic final states the positron and anti-proton spectra can be explained simultaneously. We also compare the decaying and ...

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We investigate the two-body decay modes {rho}{rho}, {pi}{pi}{sup *} (1300) and {sigma}{sigma} of the f{sub 0}(1500), all leading to the four pion decay channel, in a three-state mixing scheme, where the f{sub 0}(1500) is a mixture of the lowest lying scalar glueball with the nearby isoscalar states of the 0{sup ++}Q Q-bar nonet. In the leading order of this scheme, the decay mechanism of the f{sub 0}(1500) proceeds dominantly via its quarkonium components, which can be described in the framework of the {sup 3}P{sub 0} pair creation model. We predict the hierarchy of decay branching ratios B with B({rho}{rho}) {>=} B({pi}{pi}) {>=} B({sigma}{sigma}) > B({pi}{pi}{sup *}), providing a key signature of the proposed mixing scheme in this leading order approach. (authors)

CERN Document Server

CERN's 'Big Bang' experiment given green light

Science.gov (United States)

Thesis. Five-particle shell-model calculations, using a spin-dependent potential, were performed for the nucleus /sup 101/Tc. The effects of varying the single-particle energy differences and the strengths of the spin-dependent and pairing terms are discussed. The isobars /sup 101/Mo and /sup 101/Tc were chemically separated to enable the detailed study of their decay schemes. As a result, 184 gamma rays were observed in the decay of /sup 101/Mo, and 169 of them were assigned to 45 levels in /sup 101/Tc. In the decay of /sup 101/Tc, 27 gamma rays were observed, and 26 of them were assigned to 11 levels in /sup 101/Ru. In a study of the decays of /sup 142/Xe and /sup 142/Cs the TRI STAN on-line isotope separator was used to separate the 142 mass chain produced in /sup 235/U fission with /sup 142/2Xe as the emanating and accelerated nuclide. Isobaric separation of /sup ...

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An analysis is presented of the electron temperature in a linear device which includes the effect of thermal conduction, heat flux limit, radiation, and end plugs. It is found that the thermal conduction and the heat flux limit are dominant in the initial phase of cooling, while the later phase is almost completely controlled by radiation that spatially homogenizes the temperature distribution. In the case of bremsstrahlung, within the frame of the present model, the temperature decays to zero in a finite time. This process takes the form of a cooling wave that moves from the ends of the column to the center. Impurities cause a milder, exponential decay, which is still much faster than the algebraic conduction decay. The thermal effectiveness of the end plugs is described by a convective transfer coefficient h/sub p/. Its scaling law (in terms of the coupled plamsa-plug system) reveals that a very high plug-plasma density ...

CERN Document Server

We propose an X-ray mission called Xenia to search for decaying superweakly interacting Dark Matter particles (super-WIMP) with a mass in the keV range. The mission and its observation plan are capable of providing a major break through in our understanding of the nature of Dark Matter (DM). It will confirm, or reject, predictions of a number of particle physics models by increasing the sensitivity of the search for decaying DM by about two orders of magnitude through a wide-field imaging X-ray spectrometer in combination with a dedicated observation program. The proposed mission will provide unique limits on the mixing angle and mass of neutral leptons, right handed partners of neutrinos, which are important Dark Matter candidates. The existence of these particles is strongly motivated by observed neutrino flavor oscillations and the problem of baryon asymmetry of the Universe. In super-WIMP models, the details of the formation of the cosmic ...

CERN Document Server

We study the rates allowed for the Higgs-mediated decays $B_{s,d}^0\\to\\mu\\tau, e\\tau$ and $\\tau\\to \\mu\\mu\\mu, e\\mu\\mu$ in supersymmetric seesaw models, assuming that the only source of lepton flavour violation (LFV) is the renormalization of soft supersymmetry-breaking terms due to off-diagonal singlet-neutrino Yukawa interactions. These decays are strongly correlated with, and constrained by, the branching ratios for $B_{s,d}^0\\to\\mu\\mu$ and $\\tau\\to \\mu(e)\\gamma.$ Parametrizing the singlet-neutrino Yukawa couplings $Y_\

International Nuclear Information System (INIS)

In this work, the half-life of the "1"5"5Sm #beta#"- decay was determined using enriched "1"5"4Sm samples submitted to irradiation in the IEA-R1 reactor of IPEN; the activity of the samples were followed for 4-5 consecutive half lives using a 198 cm"3 HPGe detector. The data was corrected using a non paralizable dead time correction and fitted to an exponential decay function using a non linear fitting procedure developed on the MatLab platform. The resulting value--T_1_/_2 = 22.180(26) min--was compatible to the one found in the literature, with a lower uncertainty.

International Nuclear Information System (INIS)

The scattering of atoms by a resonance standing light wave is considered under conditions when the lower of two resonance levels is metastable, while the upper level rapidly decays due to mainly spontaneous radiative transitions to the nonresonance levels of an atom. The diffraction scattering regime is studied, when the Rabi frequency is sufficiently high and many diffraction maxima are formed due to scattering. The dynamics of spontaneous radiation of an atom is investigated. It is shown that scattering slows down substantially the radiative decay of the atom. The regions and characteristics of the power and exponential decay are determined. The adiabatic and nonadiabatic scattering regimes are studied. It is shown that the wave packets of atoms in the metastable and resonance excited states narrow down during scattering. A limiting (minimal) size of the wave packets is found, which is achieved upon nonadiabatic ...

CERN Document Server

Recent advances in our understanding of the higher-wave quarkonia have generated much interests in quarkonium physics. However most are devoted to inclusive decays and productions. Experimental data of several two-body exclusive decay channels of P-wave charmonia such as \\pi \\pi and p \\bar p are available and some have recently been re-measured by the BES collaboration. It is not clear from the outset that color octet is needed for these exclusive channels. Indeed only color singlet has been used in the past and reasonable agreement with data was found. Contrary to these old results, we provide theoretical arguments for the inclusion of color octet and perform explicit calculations to back this up.

Energy Technology Data Exchange (ETDEWEB)

The first analysis of inelastic J/{psi} meson production in photoproduction (Q{sup 2}<2.5 GeV{sup 2}) of the H1 experiment for the second phase of HERA (HERA II) is presented. The analysis is carried out at low and medium elasticities. The production of heavy quarks (charm, or bottom) is of special interest since the mass of the quarks provides a hard scale for the application of perturbative QCD. The muonic decay channel is used to select the J/{psi} mesons. The data was collected by the H1 detector during the period 2003-2005, and corresponds to an integrated luminosity of 133 pb{sup -1}. However only a subset of this data could be analysed. At the start of HERA II the trigger system was affected by a sizeable background. Then a fault was introduced in the trigger software during the summer 2004 and was only discovered and solved in April 2006. This means that approximately 80 % of the triggered events at medium elasticities and 65 % ...

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This report discusses the experimental setup of experiment 814 at Brookhaven AGS. This experiment involves the collision of silicon ions with target nuclei. The detector systems are discussed primarily. (LSP)

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A review of recent work in nuclear physics is presented. The paper gives a broad discussion of research goals in nuclear structure, quark-gluon degrees of freedom, quark-gluon plasma, symmetries, and rare decays. (DWL)

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Experimental results of nuclear reaction and radiative decay for A = 203 nuclides are evaluated. Adopted properties for all the nine isobars, Au, Hg, Tl, Pb, Bi, Po, At, Rn, Fr of mass 203 are presented. Nothing is yet known for [sup 203]Os. 96 refs.

Energy Technology Data Exchange (ETDEWEB)

The National Nuclear Data Center provides information on nuclear reactions, nuclear structure, and decay data, and is a part of the Nuclear Data Center Network, established to coordinate the compilation and dissemination of nuclear data on an international scale.

International Nuclear Information System (INIS)

The 1976 version of Nuclear Data Sheets for A = 99 (76Bu07) has been revised. Detailed level and decay schemes, arguments for J#pi# assignments, and experimental data are presented. copyright 1988 Academic Press, Inc.

International Nuclear Information System (INIS)

Evaluated nuclear structure and decay data for all nuclei within the A = 203 mass chain are presented. This work supersedes the earlier evaluation by S. Rab (1993Ra11), published in Nuclear Data Sheets 70, 173 (1993).

International Nuclear Information System (INIS)

64Cu (T1/2=12.7h, ?- decay: 40%, ?+ decay: 19%, E.C. decay: 41%) is one of the most useful radioisotope in the nuclear medicine due to its multiple decay mode and the intermediate half-life. Several nuclear reaction, i.e., 64Ni(p,n)64Cu, 68Zn(p,?n)64Cu and 64Ni(d,2n)64Cu have been investigated for production. The highest could be obtained with proton irradiation on the enriched 64Ni target. For mass and routine production, the 64Ni target fabrication using electroplating, the reliable chemical separation of 64Cu from the irradiated 64Ni target and the effective recovery process for the recycling of very expensive enriched material ($20,000/g) and so forth are absolutely necessary to be established. In this work, we report our mass production method of 64Cu with 64Ni and Cyclone-30 accelerator

International Nuclear Information System (INIS)

Microsecond pulse radiolysis of oxygenated aqueous solutions containing 0.02 mol dm"-"3 sodium formate and 2 mmol dm"-"3 phosphate buffer at pH 7 was used to generate superoxide anion radicals. The influence of some biologically important compounds upon the rate of O_2"."-"b"a"r decay as monitored spectrophotometrically in the range of 245-300 nm. Hematoporphyrin (HP), hemin C (HC), catalase (Cat), cobalt sulfophthalocyanine (CoTSPc) were studied. Among the investigated compounds only Cat was found to show a high catalytic efficiency towards the self-decay of O_2"."-"b"a"r. A red shift of 0_2"."-"b"a"r absorption band and slowing down of its decay were observed to take place by adding HP or CoTSPc to the solutions containing formate ions in excess. This effect is associated with the formation of a transient superoxo-complex. An appearance of an intermediate species with absorption maxima at 350 nm and half-life of about 2 s ...

CERN Document Server

Precise measurements of the top quark decay properties at hadron colliders offer interesting new possibilities of testing the standard model. At the same time, recent intriguing experimental results concerning CP violation in the B_d and B_s systems have stimulated many studies of physics beyond the standard model. We investigate anomalous t W d_j interactions as a possible source of new effects in B_{d,s} - bar B_{d,s} oscillations within a model independent approach based on the assumptions of Minimal Flavor Violation. After matching our effective operators onto the low-energy effective Lagrangian describing B_{d,s} meson mixing and evolving it down to the B-mass scale, we extract the preferred ranges of the anomalous t W d_j interactions at the weak scale. These values are then compared to previously considered constraints coming from the rare radiative B --> X_s gamma decay. Finally, we reconsider the associated effects in the t --> b ...

International Nuclear Information System (INIS)

The paper reports on the results of hydrodynamical simulations of the late phase of the common envelope stage of a binary consisting of a 2-solar mass red giant and a 1-solar mass main-sequence companion. The numerical results demonstrate that sufficient energy is released from the orbit to eject the mass within the common envelope without requiring the main-sequence companion to spiral into the white dwarf core of the red giant star. At the end of the simulation the orbital decay time scale increases rapidly to more than 160 yr. The long decay time scale reflects the removal of mass from the common envelope and its subsequent spin-up to near corotation. The ratio of the orbital decay time scale to the mass-loss time scale from the common envelope increases to more than 700, and the mass contained within the common envelope decreases to about 0.01 solar mass or less. It is argued that further orbital ...

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This report describes mathematical predictions for the migration of radionuclides from an emplaced radioactive waste container. The model assumes a spherical-equivalent waste solid surrounded by backfill but neglects the effect of decay heat. 7 refs., 2 tabs. (TEM)

International Nuclear Information System (INIS)

Russian 2008 p. 244 Russian Federation Artemov, SV Yarmukhamedov,

International Nuclear Information System (INIS)

The thermoluminescence (TL), blue stimulated luminescence (BSL) and infrared stimulated luminescence (IRSL) signals of fluorapatite (originating from Durango, Mexico) were measured and found to exhibit strong anomalous fading (AF). The experimentally obtained OSL and IRSL decay curves were transformed into pseudo-linear modulated (pseudo-LM) decay curves. The resulting glow-curve shaped pseudo-LM decay curves were analyzed using a deconvolution analysis, similar to the one used for the glow-curve deconvolution (GCD) of TL glow-curves. It was found that the pseudo-LM OSL and IRSL decay curves consist of two components named fast and slow, respectively, and their individual contribution was estimated. The AF of the remnant TL, BSL and IRSL as a function of the storage time was fitted using the tunneling model equations and the fading rate g, in terms of percentage per decade was evaluated. According to ...

International Nuclear Information System (INIS)

The "8"8Y decay has been studied with the aim to discover emission of monohromatic positrons (MP). The "8"8Sr(d,2N) reaction was used for production of "8"8Y (#beta#"+, Tsub(1/2)=106.6 days) nuclides. The prismatic beta spectrometer has been used to measure spectra of electrons and positrons. No MPs have been found. The resulting upper bound for their emission rate turned out to be lower than theoretically expected one.

CERN Document Server

An electroweak singlet scalar can couple to pairs of vector bosons through loop-induced dimension five operators. Compared to a Standard Model Higgs boson, the singlet decay widths in the diphotons and Z gamma channels are generically enhanced, while decays into massive final states like WW and ZZ are kinematically disfavored. The overall event rates into gamma gamma and Z gamma can exceed the Standard Model expectations by orders of magnitude. Such a singlet may appear as a resonant signal in the gamma gamma and Z gamma channels, even with a mass above the WW kinematic threshold.

International Nuclear Information System (INIS)

The theory of spontaneous decay is studied using both quantum electrodynamics (QED) and semiclassical theories of radiation. There are qualitative differences between the theories in the prediction of interference phenomena. In QED, systems which were excited with pulsed laser light do not exhibit quantum interference effects associated with lower state splittings. On the other hand, semiclassical treatments of spontaneous decay do indicate the existence of interference effects not present in QED. In addition to this, differences are found between the predictions of fluorescence intensity in the presence of lower-state level crossings under continuous excitation. (U.S.).

CERN Document Server

The processes psi'-->p pbar pi^0 and psi'-->p pbar eta are studied using a sample of 14 million psi' decays collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider. The branching fraction of psi'-->p pbar pi^0 is measured with improved precision as (13.2\\pm 1.0\\pm 1.5)\\times 10^{-5}, and psi'-->p pbar eta is observed for the first time with a branching fraction of (5.8\\pm 1.1\\pm 0.7)\\times 10^{-5}, where the first errors are statistical and the second ones are systematic.

International Nuclear Information System (INIS)

Evaluated spectroscopic data for all nuclei with mass number A = 177 and corresponding level schemes from radioactive decay and reaction studies are presented. Most of the new information since the previous evaluation of this mass chain consists of the decay of the recently discovered isotope "1"7"7Tm, and the level structure of "1"7"7Ir, "1"7"7Os, and "1"7"7Pt. The present evaluation supersedes the earlier one by Y. A. Ellis and B. Harmatz (75E107) published in Nuclear Data Sheets 16, 135 (1975).

Energy Technology Data Exchange (ETDEWEB)

The magnitude of the isospin mixing in the decay of the T/sub greater-than/ giant dipole resonance has been estimated, using the (..gamma.., n) and (..gamma..,p) cross sections available for the medium-weight nuclei /sup 60/Ni, /sup 88/Sr, /sup 89/Y, /sup 90/Zr, and /sup 92/Mo. The deduced values show a fair correspondence with the existing data for mixing between compound states. From these results the mean mixing Coulomb matrix elements between compound states could also be derived.

CERN Document Server

Contrary to some previous claims, we find a sizable instanton contribution to the finite energy sum rule used to extract the value of the strong coupling from the measured $\\tau$ decay widths. It is of the same order of magnitude as standard nonperturbative corrections induced by vacuum quark and gluon condensates. Our result indicates that there might be no hierarchy of power corrections in finite energy sum rules at the scale of $\\tau$ mass. Therefore, the standard nonperturbative corrections do not necessarily improve the accuracy of the theoretical predicition, but can rather be used to estimate an intrinsic accuracy of the pure perturbative calculation, which turns out to be rather high on this evidence, of order one percent.

CERN Document Server

The branching ratio of J/psi-->K_S K_L is measured with improved precision to be B(J/psi-->K_S K_L) = (1.82\\pm 0.04\\pm 0.13)\\times 10^{-4}. using J/psi data collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Positron Collider. This result is used to test the perturbative QCD ``12%'' rule between psi(2S) and J/psi decays and to investigate the relative phase between the three-gluon and one-photon annihilation amplitudes in J/psi decays.

Science.gov (United States)

In this work, the half-lives of the beta-unstable nuclei {sup 101}Mo and {sup 101}Tc were studied using neutron-irradiated samples of {sup 100}Mo to produce {sup 101}Mo which in its turn generates {sup 101}Tc by beta decay. The gamma activity of each sample was followed for 5 consecutive half-lives in steps of 5 minutes. A total of 22 sources were measured and checked for dead-time influence, and the half-lives were obtained by weighted average. The results are statistically incompatible with the tabulated values.

Energy Technology Data Exchange (ETDEWEB)

Intensities of {gamma}-transitions emerging from the EC decay of {sup 203}Pb were measured precisely. The obtained relative {gamma}-intensities are 100%(279.2keV), 4.14+-0.08%(401.3keV) and 0.932+-0.022%(680.5keV). The 279.2 and 680.5keV level feeding {beta}-branching ratios were deduced to be 95.3+-0.1 and 4.7+-0.1% respectively. {sup 203}Pb is suggested for calibration purposes. (author).

Energy Technology Data Exchange (ETDEWEB)

The authors present a measurement of the B{sub s}{sup 0} meson lifetime using fully and partially reconstructed hadronic decays B{sub s}{sup 0} {yields} D{sub s}{sup -} {pi}{sup +}(X) followed by D{sub s}{sup -} {yields} {phi}{pi}{sup -}. The data sample was recorded with the CDF II detector at the Fermilab Tevatron and corresponds to an integrated luminosity of 1.3 fb{sup -1} from p{bar p} collisions at {radical}s = 1.96 TeV.

International Nuclear Information System (INIS)

Beta-decay studies of the new neutron-rich isotopes sup(58,59)Cr, "6"3Mn, sup(66,67)Co and "6"9Ni, yielding distinctly shorter half-lives than the corresponding theoretical predictions, are presented. The influence of the short half-lives on the r-process calculations of nuclear abundances is discussed. It is concluded that a significantly higher neutron density than the one obtained from explosive helium burning in supernovae is needed to reproduce the observed abundances around A = 80. (orig.).

International Nuclear Information System (INIS)

The isomeric and ?-decay properties of neutron-rich 53-57Sc and 53,54Ca nuclei near neutron number N=32 are reported, and the low-energy level schemes of 53,54,56Sc and 53-57Ti are presented. The low-energy level structures of the 21Sc isotopes are discussed in terms of the coupling of the valence 1f7/2 proton to states in the corresponding 20Ca cores. Implications with respect to the robustness of the N=32 subshell closure are discussed, as well as the repercussions for a possible N=34 subshell closure.

International Nuclear Information System (INIS)

In this paper we discuss possible signatures for the production of scalar t_1t_1"* (top squarkonium) bound states #sigma#_t_1 at hadron colliders, where t_1 is the lighter scalar top eigenstate. We first study the decay of #sigma#_t_1; explicit expressions are given for all potentially important decay modes. If t_1 has unsuppressed two-body decays, they will always overwhelm the annihilation decays of #sigma#_t_1. Among the latter, we find that usually either the gg or hh final state dominates, depending on the size of the off-diagonal entry of the top squark mass matrix; h is the lighter neutral scalar Higgs boson of the minimal supersymmetric model. If m_#sigma#_t happens to be close to the mass of one of the neutral scalar Higgs bosons, Q bar Q final states dominate (Q=b or t). W"+W"- and ZZ final states are subdominant. We argue that #sigma#_t_1#->##gamma##gamma# decays offer ...

Science.gov (United States)

PMID:15343431

KoreaScience (Korea)

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CERN Document Server

Dynamic system identification

CERN Document Server

The Last Unknown Neutrino Mixing Angle $\\theta_{13}$ and the Daya Bay Experiment

Energy Technology Data Exchange (ETDEWEB)

In the context of safety assessment of radioactive waste repositories, complex radionuclide transport models covering key safety-relevant processes play a major role. In recent Swiss safety assessments, such as Kristallin-I, an important drawback was the limitation in geosphere modelling capability to account for geosphere heterogeneities. In marked contrast to this limitation in modelling capabilities, great effort has been put into investigating the heterogeneity of the geosphere as it impacts on hydrology. Structural geological methods have been used to look at the geometry of the flow paths on a small scale and the diffusion and sorption properties of different rock materials have been investigated. This huge amount of information could however be only partially applied in geosphere transport modelling. To make use of these investigations the 'PICNIC project' was established as a joint cooperation of PSI/Nagra and QuantiSci to provide a new geosphere transport ...

International Nuclear Information System (INIS)

In summary, a scaling analysis of a water-cooled Reactor Cavity Cooling System (RCCS) system was performed based on generic information on the RCCS design of PBMR. The analysis demonstrates that the water-cooled RCCS can be simulated at the ANL NSTF facility at a prototypic scale in the lateral direction and about half scale in the vertical direction. Because, by necessity, the scaling is based on a number of approximations, and because no analytical information is available on the performance of a reference water-cooled RCCS, the scaling analysis presented here needs to be 'validated' by analysis of the steady state and transient performance of a reference water-cooled RCCS design. The analysis of the RCCS performance by CFD and system codes presents a number of challenges including: strong 3-D effects in the cavity and the RCCS tubes; simulation of turbulence in flows characterized by natural circulation, high Rayleigh numbers and low Reynolds numbers; validity of heat transfer ...

Energy Technology Data Exchange (ETDEWEB)

Decay mechanism of H{sub 2}{sup -} anions produced by {gamma}-ray or X-ray radiolysis of solid para-H{sub 2} (p-H{sub 2}) has been studied using high-resolution ESR spectroscopy in the temperature range between 2.7-6.6 K. The results can be summarized as follows; First, the decay rate constant of the H{sub 2}{sup -} anion is not proportional to initial yields of reactive species such as H radical and cation but proportional to concentrations of HD and D{sub 2} impurities in p-H{sub 2}. Second, ESR spectra assigned as electron bubbles were observed in solid p-H{sub 2} containing large amount of HD or D{sub 2} (11 mol %), while they were not observed in pure solid p-H{sub 2}. Third, the decay rate constant of the H{sub 2}{sup -} anion increases with the decrease in temperature between 2.7-5 K, while it decreases with the decrease between 5-6.6 K. Fourth, the decay of the H{sub 2}{sup -} anion is ...

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The unknown {beta}-decay half-lives of 22 isotopes far off stability (5 < T{sub Z} < 10) in the region from Ti to Ni were measured at GSI, Darmstadt. The nuclei were produced in a fragmentation reaction of 500 A.MeV {sup 86}Kr-projectile impinging on a thick Be target. The isotopes of interest were separated and identified with the fragment separator, FRS, by a combination of B{rho},Z, and ToF techniques. An additional range separation was performed by a selective implantation into granular detectors. The spatial and time correlations of the implant with the consecutively detected {beta}-particles were used to determine the unknown half-lives. For nuclei far off stability, {beta}-decay chains were measured and analyzed as well, leading to an even more reliable evaluation of the lifetimes. The large discrepancies found between the measured and the theoretical values emphasize that most recent theoretical work is not an improvement over ...

International Nuclear Information System (INIS)

The decay of "1"0"1Mo to levels in "1"0"1Tc has been studied using the three-parameter (#gamma#-#gamma#-t) coincidence system of HpGe-HpGe detectors. According to the coincidence data, the decay scheme was modified. The positions of 221.80, 318.00, 377.90, 452.50, 515.42, 1011.05 and 1759.72 keV transitions have been arranged again, the transition positions of 104.70, 105.95 and 774.15 keV gamma-rays have been assigned for the first time, the positions of 169.00, 590.91, 980.52 and 1431.68 keV transitions have been reconfirmed, the 1508.01 keV gamma-ray was observed simultaneously for the first time and its transition position has been assigned. The #beta#-intensities and the values of log ft of most levels were calculated. (author)

Science.gov (United States)

Decay heat removal analyses for lead-bismuth cooled natural circulation reactors are described in this paper. A combined multi-dimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural circulation reactors. For the preliminary study, transient analysis has been performed for a 100 MWe lead-bismuth-cooled reactor designed by Argonne National Laboratory (ANL). In addition, decay heat removal characteristics of a 400 MWe lead-bismuth-cooled natural circulation reactor designed by Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. PRACS (Primary Reactor Auxiliary Cooling System) is prepared for the JNC's concept to get sufficient heat removal capacity. During 2000 sec after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 Centigrade, because the buoyancy force in a primary circulation path is temporary ...

Science.gov (United States)

The long operating cycle simplified boiling water reactor is a reactor concept that pursues both safety and the economy by employing a natural circulation reactor core without a refueling, a passive decay heat removal, and an integrated building for the reactor and turbine. Throughout the entire spectrum of the design basis accident, the reactor core is kept covered by the passive emergency core cooling system. The decay heat is removed by the conventional active low-pressure residual heat removal system. As for a postulated severe accident, the suppression pool water floods the lower part of the reactor pressure vessel (RPV) in the case when core damage occurs, and the in-vessel retention that keeps the melt inside the RPV is achieved by supplying the coolant. The containment adopts a parallel-double-steel-plate structure similar to a hull structure, which contains coolant between the inner and outer walls to absorb the heat transferred from ...

Science.gov (United States)

The 10.3-h /sup 165/Er, decaying by electron capture to stable /sup 165/Ho, offers an excellent promise for use in diagnostic nuclear medicine, especially in conjuction with multiwire proportional-counter cameras. Using an ultra-high-resolution Si(Li) photon spectrometer, L and K x-ray photon yields in /sup 165/Er decay have been measured. The ratio P/sub L//P/sub K/ of electron-capture probabilities in L and K shells is determined to be 0.196 +- 0.030, in good agreement with theory. Estimates of Auger electron yields and yields of very-low-energy electrons from Coster--Kronig transitions are presented. Levels of /sup 169/Er and /sup 171/Er radioactive impurities in the reactor-produced /sup 165/Er sample are experimentally determined. Whole-body dose estimates for /sup 165/Er are given. These compare favorably with /sup 99/Tc dose.

Energy Technology Data Exchange (ETDEWEB)

Enhanced superlattice disordering in nonstoichiometric AlAs/GaAs quantum wells exhibits weak temperature dependence because of the decay of the supersaturated concentration of group-III vacancies. We present a formalism for transient enhanced diffusion in nonstoichiometric materials with which we can extract migration enthalpies {ital H}{sub {ital m}} by assuming that the vacancy decay is thermally activated with an enthalpy {ital H}{sub {ital a}}. By analyzing the electroabsorption from the quantum-confined Stark effect for a set of isochronal and isothermal anneals, we extract a migration enthalpy {ital H}{sub {ital m}}=(1.8{plus_minus}0.2) eV for group-III vacancies, as well as an activation enthalpy {ital H}{sub {ital a}}=(0.7{plus_minus}0.2) eV for vacancy annihilation. {copyright} {ital 1996 American Institute of Physics.}

International Nuclear Information System (INIS)

Radionuclides exhibiting in decaying a strong interaction between nucleus and electron shell (especially electron capture and internal conversion) are, in principle, sensitive to their chemical surroundings. Consequently, they can be used to yield chemical information after an appropriate labelling procedure. The information can be extracted from the decay rate variation as well as from their X-ray emission as a response to an inner-shell vacancy creation during nuclear deexcitation. As an example of the former method the relationship between the decay rate of /sup 99m/Tc and the chemical structures of pertechnetate and bis(meso-dimercapto-succinate)oxotechnetate(V) is considered. Lower expectations with respect to measuring techniques are associated with the observation of X-ray emission. For a number of elements (especially 3d transition elements) the K/sub #alpha#//K/sub #betta#/ X-ray intensity ratio was found to be an ...

Energy Technology Data Exchange (ETDEWEB)

We study the condensation of localized closed string tachyons on AdS orbifolds both from the bulk and boundary theory viewpoints. We first extend the known results for AdS{sub 5}/Z{sub k} to AdS{sub 3}/Z{sub k} case, and we proposed that the AdS{sub 3}/Z{sub k} decays into AdS{sub 3}/Z{sub k'} with k{sup '} < k. From the bulk viewpoint, we obtain a time-dependent gravity solution describing the decay of AdS orbifold numerically. From the dual gauge theory viewpoint, we calculated the Casimir energies of gauge theory vacua and it is found that their values are exactly the same as the masses of dual geometries, even though they are in different parameter regimes of 't Hooft coupling. We also consider AdS{sub 5} orbifold. The decay of AdS{sub 5}/Z{sub k} is dual to the transition between the vacua of dual gauge theory on R{sub t} x S{sup 3}/Z{sub k}. We constructed the instanton solutions ...

International Nuclear Information System (INIS)

In order to improve the measuring efficiency, a 'proton-gamma' coincidence technique in combination with a He-jet tape transport system was proposed and employed to identify the #beta#-delayed proton precursors. The study of #beta#-delayed proton decays near the proton drip line by using the 'proton-gamma' coincidence technique over the last 5 years at the Institute of Modern Physics, Lanzhou, China, was summarized. New #beta#-delayed proton precursors "1"2"1Ce, "1"2"5Nd, "1"2"8Pm, "1"2"9Sm, "1"3"5Gd, "1"3"7Gd, "1"3"9Dy, "1"4"2Ho, and "1"4"9Yb in the rare-earth region along a speculated proton drip line were synthesized and identified for the first time. The #beta#-delayed proton decays of "8"1Zr, "8"5Mo, "8"9Ru, and "9"3Pd in T_z=1/2 series as well as "9"2Rh in T_z=1 series were observed.

British Library Electronic Table of Contents (United Kingdom)

This study examined the life histories of a group of emerging scholars in the field of mathematics education who identify themselves as having a particular interest in and concern for issues of equity and diversity. Experiences of being the "other," "bearing witness" to "othering experiences," and "orienting experiences" in relation to issues of equity proved to be prominent themes in participants' life histories. These experiences were then linked to the positionality that these scholars now have in relation to their research in mathematics education.

International Nuclear Information System (INIS)

Time-odd parton distribution functions in a Drell-Yan process are here studied by examining the evolution of the internal statistical properties of the interacting hadrons. Time-odd functions are shown to be a signature of the irreversible process in which a hadronic state characterized by long range correlation properties (hadronic phase) decays to produce a cloud of independent partons (partonic phase) because of initial/final state interactions. The relevant considered variable is the rate of increase of the entropy of the hadronic system. This quantity is shown to be roughly equal to the decay rate of the hadronic state. Conditions for getting a leading twist time-odd effect are established on this basis. Last, the relevant case of a large entropy increase associated with transverse-dominated initial/final state interactions is analyzed.

Energy Technology Data Exchange (ETDEWEB)

In this paper we present an approach to study the radiative decay modes of the J/{psi} into a photon and one of the tensor mesons f{sub 2}(1270), f' {sub 2}(1525), as well as the scalar ones f{sub 0}(1370) and f{sub 0}(1710). Especially, we compare predictions that emerge from a scheme where the states appear dynamically in the solution of vector meson-vector meson scattering amplitudes to those from a (admittedly naive) quark model. We provide evidence that it might be possible to distinguish amongst the two scenarios, once improved data are available. (orig.)

CERN Document Server

We report the first observation of $\\mPJpsi \\to \\mPeta\\mPKst\\mAPKst$ decay in a $\\mPJpsi$ sample of 58 million events collected with the BESII detector. The branching fraction is determined to be $(1.15 \\pm 0.13 \\pm 0.22)\\times 10^{-3}$. The selected signal event sample is further used to search for the $\\mPY$ resonance through $\\mPJpsi \\to \\mPeta \\mPY, \\mPY\\to\\mPKst\\mAPKst$. No evidence of a signal is seen. An upper limit of \\mathrm{Br}(\\mPJpsi \\to \\mPeta \\mPY)\\cdot\\mathrm{Br}(\\mPY\\to\\mPKst\\mAPKst) < 2.52\\times 10^{-4} is set at the 90% confidence level.

International Nuclear Information System (INIS)

An investigation of decay heat removal by the reflux boiling process was performed on a 1/18 linear-scaled test facility simulating the Three Mile Island (TMI-2) primary system. The objective was to clarify reflux boiling phenomena and core cooling effectiveness. Principal test variables included: core power, primary system water and gas inventories, and steam generator secondary-side coolant flow rate. Of 49 tests conducted, 43 achieved a steady-state heat rejection mode within 3 hours. Subsequent analyses identified two distinct reflux boiling modes. Based upon our current understanding, reflux boiling appears to be an effective process for removing decay heat in a broad range of the conditions investigated for a plant of the TMI configuration.

CERN Document Server

We compute QCD corrections to the production of a ttbar pair in association with a hard photon at the Tevatron and the LHC. This process allows a direct measurement of the top quark electromagnetic couplings that, at the moment, are only loosely constrained. We include top quark decays, treating them in the narrow width approximation, and retain spin correlations of final-state particles. Photon radiation off top quark decay products is included in our calculation and yields a significant contribution to the cross-section. We study next-to-leading order QCD corrections to the ppbar -> ttbar+gamma process at the Tevatron for the selection criteria used in a recent measurement by the CDF collaboration. We also discuss the impact of QCD corrections to the pp -> ttbar+gamma process on the measurement of the top quark electric charge at the 14 TeV LHC.

CERN Document Server

Decays of $\\chi_{c0,2}\\ar\\ww$ are observed for the first time using a sample of $14.0\\times 10^6$ $\\psi(2S)$ events collected with the BESII detector. The branching ratios are determined to be ${\\cal B}(\\chi_{c0}\\ar \\ww)=(2.29\\pm 0.58\\pm 0.41)\\times 10^{-3}$ and ${\\cal B}(\\chi_{c2}\\ar\\ww)=(1.77\\pm 0.47\\pm 0.36)\\times 10^{-3}$, where the first errors are statistical and the second systematic. The significances of the two signals are $4.4\\sigma$ and $4.7\\sigma$, respectively.

Energy Technology Data Exchange (ETDEWEB)

The effects of spin diffusion on the free induction decay (FID) of protons associated with the noncrystalline domains of two polymers, polyethylene and blended Nylon 66 (ZYTEL-408), have been examined using Goldman--Shen NMR pulse sequence ((1/2)..pi..x-t/sub 0/-(1/2)..pi..x-bar-tau-(1/2)..pi..x-t). At tau< or approx. =100 ..mu..s, the FID is drastically distorted from the exponential form while at longer tau(tau> or approx. =500 ..mu..s) an exponential FID is observed; but its transverse spin relaxation rate is smaller than that of the FID obtained after a single (1/2)..pi..x pulse and approaches this value at the limit of large tau. These findings are interpreted in terms of the theory of rapid spin diffusion. The spatial variation in the spin relaxation rate within the noncrystalline domain is inferred.

Energy Technology Data Exchange (ETDEWEB)

The energy level schemes of {sup 152}Gd and {sup 152}Sm have been established on the basis of single gamma-spectra, and gamma-gamma coincidence measurements. Ge(Li) detectors were used to study the gamma spectra produced in the EC/beta{sup +} and beta{sup -} decays of {sup 152}Eu to {sup 152}Sm and {sup 152}Gd, respectively. Thirteen new transitions are reported and data from eleven coincidence gates enabled five new levels to be suggested. Relative intensities and log ft values were calculated and spin/parities deduced. Comparisons are made with new predictions of the Interacting Boson Model. (orig.).

International Nuclear Information System (INIS)

In a series of recent papers, Corben recovered various properties of many hadronic resonances by considering them as compounds of a bradyon and of one (or more) tachyons. In this note it is explained why that success follows from considering the tachyon four-momenta orthogonal to the bradyon one, and why, in such a case, the bradyon and tachyons can be formally dealt with as non-interacting even when they keep participating in the ''self-trapping''. Finally an attempt is made to understand (on the basis of the model by Caldirola, Pavsic and Recami where hadrons are considered as ''strong black-holes'') why in general those compound hadrons decay and why in this decay the trapped tachyons are, quantum-mechanically, emitted in the corresponding bradyonic form.

Energy Technology Data Exchange (ETDEWEB)

Evidence is reported for a narrow structure near the J/{psi}{phi} threshold in exclusive B{sup +} {yields} J/{psi}{phi}K{sup +} decays produced in {bar p}p collisions at {radical}s = 1.96 TeV. A signal of 14 {+-} 5 events, with statistical significance in excess of 3.8 standard deviations, is observed in a data sample corresponding to an integrated luminosity of 2.7 fb{sup -1}, collected by the CDF II detector. The mass and natural width of the structure are measured to be 4143.0 {+-} 2.9(stat) {+-} 1.2(syst) MeV/c{sup 2} and 11.7{sub -5.0}{sup +8.3}(stat) {+-} 3.7(syst) MeV/c{sup 2}.

Science.gov (United States)

The use of chemically selective laser ionization combined with beta-delayed neutron counting at ISOLDE has permitted identification and half-life measurements for {sup 61}Mn up through {sup 69}Mn. The 14(4)-ms half life for {sup 69}Mn is one of the shortest determined for any nuclide beyond the sd shell. Gamma-ray singles and coincidence spectra have been determined for the decays of {sup 64,66}Mn to levels of {sup 64,66}Fe, revealing strong deformation and vanishing of the N=40 subshell in the Fe isotopes. {copyright} {ital 1998 American Institute of Physics.}

Energy Technology Data Exchange (ETDEWEB)

The use of chemically selective laser ionization combined with {beta} -delayed neutron counting at CERN/ISOLDE has permitted identification and half-life measurements for 623-ms {sup 61}Mn up through 14-ms {sup 69}Mn . The measured half-lives are found to be significantly longer near N=40 than the values calculated with a quasiparticle random-phase-approximation shell model. Gamma-ray singles and coincidence spectroscopy has been performed for {sup 64,66}Mn decays to levels of {sup 64,66}Fe , revealing a significant drop in the energy of the first 2{sup +} state in these nuclides that suggests an unanticipated increase in collectivity near N=40 . {copyright} {ital 1999} {ital The American Physical Society }

Energy Technology Data Exchange (ETDEWEB)

Radon concentration measurements were performed for one year in 12 different boron, chromium and coal underground mines in Western Turkey. Lucas cells and nuclear track detectors were used for the measurements of radon and its decay products. The effects of parameters, such as type of mine, gallery depth and ventilation rate, on the radon concentration in mine air were examined. The radiation exposure doses of miners due to the inhalation of radon and radon daughters were determined. Gamma survey measurements were also realized together with radon measurements and the total effective dose equivalents in mSv y{sup -1} were estimated.

Energy Technology Data Exchange (ETDEWEB)

A numerical analysis is performed to clarify the heat transfer characteristics of combined convection around the tubes which form a single row perpendicularly arranged to a forced flow in the direction of gravity. A boundary-fitted coordinate transformation technique is adopted to solve the governing equations numerically. It is found in the case of liquid sodium that gravity-induced flow gives no substantial effect to heat transfer augmentation in a low Reynolds number region while it can be sufficiently expected in the ordinary fluids in the same Reynolds number region. This means that such heat transfer augmentation as expected in ordinary fluids can not be realized when crossflow-type heat exchangers installed for decay-heat removal operates in a low Reynolds number region.

Energy Technology Data Exchange (ETDEWEB)

The reaction mechanism underlying the 44 MeV/u {sup 40}Ar projectile break-up process has been studied on different targets, by measuring the coincidences between light particles or intermediate mass fragments detected in a large angular range, and projectile fragments or light charged particles. While the experimental data relative to projectile-like fragments (PLF) with charge close to the one of the projectile can be interpreted in the framework of a three source analysis, the anomalous light fragment production with Z {<=} 10 rather suggests `fission` as one of the possible decay mode of the highly excited projectile or PLF. It is also observed that a great amount of the forward detected light charged particles are correlated, and due to the break-up or decay of light excited ions. (author). 9 refs.

Science.gov (United States)

Three major series of experiments have been conducted with the FELIX facility at ANL. Experiments on the coupling between eddy currents and angular displacements of loops and plates in crossed constant and changing magnetic fields demonstrated that the co...

International Nuclear Information System (INIS)

Search for the value of ?13 mixing angle is of importance in understanding the lepton flavor mixing matrix, and in motivating future experiments to probe CP violation in the lepton sector. Among the present experimental approaches, reactor experiment can provide a clean laboratory for the ?13-measurement. The Daya Bay experiment will start civil construction this year at Daya Bay, Guangdong, China. The goal of this experiment is to reach a sensitivity in sin2 2?13 of < 0.01 at 90% C.L. by precisely measuring the disappearance and spectral distortion of reactor electron anti-neutrinos with multiple identical detectors at different baselines. The talk will present the current status and prospects of the experiment.

UK PubMed Central (United Kingdom)

The supernatural fears associated with the experience of isolated sleep paralysis in the culture of developing countries is sometimes associated with the evolution of somatic symptoms of psychological...Full Text Available

International Nuclear Information System (INIS)

A theoretical analysis of two-dimensional unsteady flow in a porous medium bounded by a horizontal wall is presented as a perturbation on a basic flow. It is assumed that the perturbation is occasioned by a sudden suction at the wall. Even for a highly permeable medium the characteristic Reynolds number in porous media flow is usually small and asymptotic solutions are developed by the Laplace transform technique. It is observed that the perturbed shear stress at the wall decays exponentially with time. (author). 5 refs.

International Nuclear Information System (INIS)

The method and results are presented of measurements of the coefficients of "2"2"2Rn emanation from samples of fly- ashes and slag and other commonly used building materials. A chamber was used for electrostatic collection of "2"2"2Rn decay products. The coefficients of emanation ranged from 0.2% (fly- ashes) to 21.3% (phosphogipsum from phosphorit). (author).

International Nuclear Information System (INIS)

The possible role of space-like objects in elementary particle physics (and in quantum mechanics) is reviewed and discussed, mainly by exploiting the explicit consequences of the peculiar relativistic mechanics of Tachyons. Particular attention is paid: (i) to tachyons as the possible carriers of interactions; (ii) to the possibility of ''vacuum decays'' at the classical level; (iii) to a Lorentz-invariant bootstrap model; (iv) to the apparent shape of the tachyonic elementary particles and its possible connection with the de Broglie wave-particle dualism. (author).