Cross sections, average multiplicities and energy fractions of neutral π- and k-mesons in p anti p-annihilations at 22.4 GeV/c

International Nuclear Information System (INIS)

Batyunya, B.V.; Boguslavsky, I.V.; Gramenitsky, I.M.

1982-01-01

To determine cross sections, average multiplicities and inelasticity coefficients π 0 and Ksub(n), formed in anti pp annihilation interaction at 22.4 GeV/c, data on the differences in the respective characteristics anti pp- and pp-interactions have been used. The average multiplicity of π 0 in anti pp annihilation interactions is equal to 3.2+-0.3 and exceeds analogous data for inelastic pp- and anti pp interactions. The inelasticity coefficient π + , π 0 and Ksub(n)/Ksup(0) or anti K 0 /of mesons formed in annihilation interactions: etasub(π)sup(+)=0.33+-0.22, etasub(πsup(0)=0.36+-0.05, etasub(Ksubn))=0.044+-0.008 is determined. The total multiplicity of charged and neutral particles formed in anti pp annihilation at 22.4 GeV/c equals 10.2+-0.4 and exceeds the corresponding values for inelastic anti pp and pp interactions

Contributions of scalar leptoquarks to the cross sections for the production of quark-antiquark pairs in electron-positron annihilation

International Nuclear Information System (INIS)

Povarov, A.V.; Smirnov, A.D.

2003-01-01

The contributions of scalar-leptoquark doublets to the cross sections σ QQ-tilde ' for the production of quark-antiquark pairs in electron-positron annihilation are calculated within the minimal model based on the four-color symmetry of quarks and leptons. These contributions are analyzed versus the scalar-leptoquark masses and the mixing parameters of the model at colliding-particle energies in the range 250-1000 GeV. It is shown that the contributions in question are of greatest importance for processes leading to t-quark production. In particular, it is found that, with allowance for the contribution of the scalar leptoquark of charge 5/3 and mass in the range 250-500 GeV, the cross section σ tt-tilde calculated at a mixing-parameter value of k t ∼ 1 may be severalfold larger than the corresponding cross section σ tt-tilde (SM) within the Standard Model. The possibility of setting constraints on the scalar-leptoquark masses and on the mixing parameters by measuring such contributions at future electron-positron colliders is indicated

Self-scattering cross-section of molecules in a beam

International Nuclear Information System (INIS)

Lou, Y.S.

1974-01-01

Molecular collision cross-section has always been measured by the beam scattering method, or by the measurements of thermal conductivity and/or viscosity coefficient, etc. The cross-section thus obtained has been found to be different, qualitatively, from that of the self-scattering of the molecules moving within a molecular beam. By perturbing the zeroth order solution of the Boltzmann equation with a B-G-K kinetic model for the gas upstream to the orifice, and performing particle scattering calculation for molecules within the beam downstream to the orifice, such self-scattering collision cross-section can be determined from the experimental data of velocity distribution functions of molecules in the beam

Antiproton-helium annihilation around 45 MeV/c

International Nuclear Information System (INIS)

Balestra, F.; Bassolasco, S.; Bussa, M.P.; Busso, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F.; Barbieri, R.; Bendiscioli, G.; Filippini, V.; Rotondi, A.; Salvini, P.; Zenoni, A.; Batusov, Yu.A.; Falomkin, I.V.; Pontecorvo, G.B.; Rozhdestvensky, A.M.; Sapozhnikov, M.G.; Tretyak, V.I.; Breivik, F.O.; Jacobsen, T.; Soerensen, S.O.

1989-01-01

The anti p 4 He annihilation cross section averaged over the interval 40-50 MeV/c has been measured using a streamer chamber in a magnetic field. The measured value is 1342±250 mb. It agrees with a behaviour like 1/p of the annihilation cross section. Our result has been obtained at the lowest momentum achieved till now in measurements of antiproton annihilation in flight. (orig.)

Antiproton-helium annihilation around 45 MeV/c

Energy Technology Data Exchange (ETDEWEB)

Balestra, F.; Bassolasco, S.; Bussa, M.P.; Busso, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F. (Turin Univ. (Italy). Ist. di Fisica Generale; Istituto Nazionale di Fisica Nucleare, Turin (Italy)); Barbieri, R.; Bendiscioli, G.; Filippini, V.; Rotondi, A.; Salvini, P.; Zenoni, A. (Pavia Univ. (Italy). Dipt. di Fisica Nucleare e Teorica; Istituto Nazionale di Fisica Nucleare, Pavia (Italy)); Batusov, Yu.A.; Falomkin, I.V.; Pontecorvo, G.B.; Rozhdestvensky, A.M.; Sapozhnikov, M.G.; Tretyak, V.I. (Joint Inst. for Nuclear Research, Dubna (USSR)); Breivik, F.O.; Jacobsen, T.; Soerensen, S.O. (Oslo Univ. (Norway). Fysisk Inst.); Guaraldo, C.; Maggiora, A. (Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati); Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M. (Bergen Univ. (Norway). Dept. of Physics); Lodi Rizzini, E. (Brescia Univ. (Italy). Dipt. di Automazione Industriale); Masala, M. (Brescia Univ. (Italy). Dipt. di Automazione Ind

1989-10-26

The anti p{sup 4}He annihilation cross section averaged over the interval 40-50 MeV/c has been measured using a streamer chamber in a magnetic field. The measured value is 1342+-250 mb. It agrees with a behaviour like 1/p of the annihilation cross section. Our result has been obtained at the lowest momentum achieved till now in measurements of antiproton annihilation in flight. (orig.).

Hadron production by e+e- annihilation at center-of-mass energies between 2.6 and 7.8 GeV. I. Total cross section, multiplicities, and inclusive momentum distributions

International Nuclear Information System (INIS)

Siegrist, J.L.; Schwitters, R.F.; Alam, M.S.; Boyarski, A.M.; Breidenbach, M.; Bulos, F.; Dakin, J.T.; Dorfan, J.M.; Feldman, G.J.; Fryberger, D.; Hanson, G.; Jaros, J.A.; Jean-Marie, B.; Larsen, R.R.; Lueth, V.; Lynch, H.L.; Lyon, D.; Morehouse, C.C.; Perl, M.L.; Peruzzi, I.; Piccolo, M.; Pun, T.P.; Rapidis, P.; Richter, B.; Schindler, R.H.; Tanenbaum, W.; Vannucci, F.; Chinowsky, W.; Abrams, G.S.; Briggs, D.; Carithers, W.C.; Cooper, S.; DeVoe, R.G.; Friedberg, C.E.; Goldhaber, G.; Hollebeek, R.J.; Johnson, A.D.; Kadyk, J.A.; Litke, A.M.; Madaras, R.J.; Nguyen, H.K.; Pierre, F.M.; Sadoulet, B.; Trilling, G.H.; Whitaker, J.S.; Wiss, J.E.

1982-01-01

Measurements of multihadron production in e + e - annihilation at center-of-mass energies between 2.6 and 7.8 GeV are presented. Aside from the narrow resonances psi(3095) and psi(3684), the total hadronic cross section is found to be approximately 2.7 times the cross section for the production of muon pairs at c.m. energies below 3.7 GeV and 4.3 times the muon-pair cross section at c.m. energies above 5.5 GeV. Complicated structure is found at intermediate energies. Charged-particle multiplicities and inclusive momentum distributions are presented

Multiwavelength analysis of dark matter annihilation and RX-DMFIT

International Nuclear Information System (INIS)

McDaniel, A.; Jeltema, T.; Profumo, S.; Storm, E.

2017-01-01

Dark matter (DM) particles are predicted by several well motivated models to yield Standard Model particles through self-annihilation that can potentially be detected by astrophysical observations. In particular, the production of charged particles from DM annihilation in astrophysical systems that contain magnetic fields yields radio emission through synchrotron radiation and X-ray emission through inverse Compton scattering of ambient photons. We introduce RX-DMFIT, a tool used for calculating the expected secondary emission from DM annihilation. RX-DMFIT includes a wide range of customizable astrophysical and particle parameters and incorporates important astrophysics including the diffusion of charged particles, relevant radiative energy losses, and magnetic field modelling. We demonstrate the use and versatility of RX-DMFIT by analyzing the potential radio and X-ray signals for a variety of DM particle models and astrophysical environments including galaxy clusters, dwarf spheroidal galaxies and normal galaxies. We then apply RX-DMFIT to a concrete example using Segue I radio data to place constraints for a range of assumed DM annihilation channels. For WIMP models with M χ ≤ 100 GeV and assuming weak diffusion, we find that the leptonic μ + μ − and τ + τ − final states provide the strongest constraints, placing limits on the DM particle cross-section well below the thermal relic cross-section, while even for the b b-bar channel we find limits close to the thermal relic cross-section. Our analysis shows that radio emission provides a highly competitive avenue for dark matter searches.

Multiwavelength analysis of dark matter annihilation and RX-DMFIT

Energy Technology Data Exchange (ETDEWEB)

McDaniel, A.; Jeltema, T.; Profumo, S. [Department of Physics, University of California, 1156 High St. Santa Cruz, CA, 95064 (United States); Storm, E., E-mail: alexmcdaniel@ucsc.edu, E-mail: tesla@ucsc.edu, E-mail: profumo@ucsc.edu, E-mail: e.m.storm@uva.nl [GRAPPA, Institute of Physics, Universiteit van Amsterdam Science Park 904, 1098XH Amsterdam (Netherlands)

2017-09-01

Dark matter (DM) particles are predicted by several well motivated models to yield Standard Model particles through self-annihilation that can potentially be detected by astrophysical observations. In particular, the production of charged particles from DM annihilation in astrophysical systems that contain magnetic fields yields radio emission through synchrotron radiation and X-ray emission through inverse Compton scattering of ambient photons. We introduce RX-DMFIT, a tool used for calculating the expected secondary emission from DM annihilation. RX-DMFIT includes a wide range of customizable astrophysical and particle parameters and incorporates important astrophysics including the diffusion of charged particles, relevant radiative energy losses, and magnetic field modelling. We demonstrate the use and versatility of RX-DMFIT by analyzing the potential radio and X-ray signals for a variety of DM particle models and astrophysical environments including galaxy clusters, dwarf spheroidal galaxies and normal galaxies. We then apply RX-DMFIT to a concrete example using Segue I radio data to place constraints for a range of assumed DM annihilation channels. For WIMP models with M {sub χ} ≤ 100 GeV and assuming weak diffusion, we find that the leptonic μ{sup +}μ{sup −} and τ{sup +}τ{sup −} final states provide the strongest constraints, placing limits on the DM particle cross-section well below the thermal relic cross-section, while even for the b b-bar channel we find limits close to the thermal relic cross-section. Our analysis shows that radio emission provides a highly competitive avenue for dark matter searches.

Cross-Sectional and Longitudinal Comparisons of Adolescent Self-Esteem.

Science.gov (United States)

Mullis, Ann K.; And Others

1992-01-01

Examined self-esteem of adolescents over three years of high school. Ninth graders (n=270) completed Coopersmith Self-Esteem Inventory for each of three years. Found grade level significantly related to self-esteem in longitudinal but not cross-sectional design. Mediational effects of gender and socioeconomic status were found to be minimal.…

GROUPIE2007, Bondarenko Self-Shielded Cross sections from ENDF/B

International Nuclear Information System (INIS)

2007-01-01

1 - Description of problem or function - GROUPIE reads evaluated data in ENDF/B Format and uses these to calculate unshielded group averaged Cross sections, Bondarenko self-shielded Cross sections, and multiband parameters. The program allows the user to specify arbitrary energy groups and an arbitrary energy-dependent neutron spectrum (weighting function). IAEA0849/15: This version include the updates up to January 30, 2007. Changes in ENDF/B-VII Format and procedures, as well as the evaluations themselves, make it impossible for versions of the ENDF/B pre-processing codes earlier than PREPRO 2007 (2007 Version) to accurately process current ENDF/B-VII evaluations. The present code can handle all existing ENDF/B-VI evaluations through release 8, which will be the last release of ENDF/B-VI. 2 - Modifications from previous versions: Groupie VERS. 2007-1 (Jan. 2007): checked against all ENDF/B-VII; increased page size from 120,000 to 600,000 points. 3 - Method of solution: All integrals are performed analytically; in no case is iteration or any approximate form of integration used. GROUPIE reads either the 0 deg. Kelvin Cross sections or the Doppler broadened Cross sections to calculate the self-shielded Cross sections and multiband parameters for 25 values of the 'background' Cross sections (representing the combined effects of all other isotopes and of leakage). 4 - Restrictions on the complexity of the problem: GROUPIE requires that the energy-dependent neutron spectrum and all Cross sections be given in tabular form, with linear interpolation between tabulated values. There is no limit to the size of the table used to describe the spectrum, so the spectrum may be described in as much detail as required. - If only unshielded averages are calculated, the program can handle up to 3000 groups. If self-shielded averages and/or multiband parameters are calculated, the program can handle up to 175 groups. These limits can easily be extended. - The program only uses the

Investigation of the total charm-pair cross section in nonresonant e+e- annihilations at √s = 10.5 GeV

International Nuclear Information System (INIS)

Bowcock, T.; Kinoshita, K.; Pipkin, F.M.

1988-01-01

We report results from two new methods for measuring the total production of charmed particles in nonresonant e + e - annihilations at √s = 10.5 GeV. The rate for detection of events containing two reconstructed charmed mesons relative to that for events containing one is used to extract information about total charm production independent of decay branching fractions. The value of ΔR/sub c//sub c-bar/, the total charm-pair cross section normalized to the pointlike μ-pair cross section, is found to be 1.13/sub -0.13//sup +0.17/ +- 0.09, under an assumption of limited particle correlations. In an independent analysis the inclusive cross section for e + e - →qq-bar→e/sup +- /X is measured to be 0.293 +- 0.017 +- 0.017 nb. Using measured relative production rates and semileptonic branching fractions of D 0 and D + mesons and estimates of these quantities for D/sub s/ and Λ/sub c/, this is found to correspond to ΔR/sub c//sub c-bar/ = 2.07 +- 0.12 +- 0.26. These two measurements are discussed in the context of measurements made by reconstruction of exclusive hadronic decay modes and of theoretical expectations

Solar atmospheric neutrinos and the sensitivity floor for solar dark matter annihilation searches

Energy Technology Data Exchange (ETDEWEB)

Argüelles, C.A. [Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge MA (United States); De Wasseige, G. [Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Brussels (Belgium); Fedynitch, A. [Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); Jones, B.J.P., E-mail: caad@mit.edu, E-mail: gdewasse@vub.ac.be, E-mail: anatoli.fedynitch@desy.de, E-mail: ben.jones@uta.edu [University of Texas at Arlington, 108 Science Hall, 502 Yates St, Arlington TX (United States)

2017-07-01

Cosmic rays interacting in the solar atmosphere produce showers that result in a flux of high-energy neutrinos from the Sun. These form an irreducible background to indirect solar WIMP self-annihilation searches, which look for heavy dark matter particles annihilating into final states containing neutrinos in the Solar core. This background will eventually create a sensitivity floor for indirect WIMP self-annihilation searches analogous to that imposed by low-energy solar neutrino interactions for direct dark matter detection experiments. We present a new calculation of the flux of solar atmospheric neutrinos with a detailed treatment of systematic uncertainties inherent in solar atmospheric shower evolution, and we use this to derive the sensitivity floor for indirect solar WIMP annihilation analyses. We find that the floor lies less than one order of magnitude beyond the present experimental limits on spin-dependent WIMP-proton cross sections for some mass points, and that the high-energy solar atmospheric neutrino flux may be observable with running and future neutrino telescopes.

Searches for dark matter self-annihilation signals from dwarf spheroidal galaxies and the Fornax galaxy cluster with imaging air Cherenkov telescopes

International Nuclear Information System (INIS)

Opitz, Bjoern Helmut Bastian

2014-06-01

Many astronomical observations indicate that dark matter pervades the universe and dominates the formation and dynamics of cosmic structures. Weakly interacting massive particles (WIMPs) with masses in the GeV to TeV range form a popular class of dark matter candidates. WIMP self-annihilation may lead to the production of γ-rays in the very high energy regime above 100 GeV, which is observable with imaging air Cherenkov telescopes (IACTs). For this thesis, observations of dwarf spheroidal galaxies (dSph) and the Fornax galaxy cluster with the Cherenkov telescope systems H.E.S.S., MAGIC and VERITAS were used to search for γ-ray signals of dark matter annihilations. The work consists of two parts: First, a likelihood-based statistical technique was introduced to combine published results of dSph observations with the different IACTs. The technique also accounts for uncertainties on the ''J factors'', which quantify the dark matter content of the dwarf galaxies. Secondly, H.E.S.S. observations of the Fornax cluster were analyzed. In this case, a collection of dark matter halo models was used for the J factor computation. In addition, possible signal enhancements from halo substructures were considered. None of the searches yielded a significant γ-ray signal. Therefore, the results were used to place upper limits on the thermally averaged dark matter self-annihilation cross-section left angle σν right angle. Different models for the final state of the annihilation process were considered. The cross-section limits range from left angle σν right angle UL ∝10 -19 cm 3 s -1 to left angle σν right angle UL ∝10 -25 cm 3 s -1 for dark matter particles masses between 100 GeV and 100 TeV. Some of the diverse model uncertainties causing this wide range of left angle σν right angle UL values were analyzed.

Quasinuclear baryonium and annihilation

International Nuclear Information System (INIS)

Kerbikov, B.O.; Shapiro, I.S.

1978-01-01

The properties of the quasinuclear baryonium are considered in the framework of the dynamical coupled channel model. The main principles of the model are reviewed. The energy spectrum of the N anti N system and the problem of the baryonium radius are discussed. A detailed investigation of the problem of baryonium annihilation width and the low energy N anti N annihilation cross section is presented

Radiative bound-state-formation cross-sections for dark matter interacting via a Yukawa potential

Energy Technology Data Exchange (ETDEWEB)

Petraki, Kalliopi [LPTHE, CNRS, UMR 7589,4 Place Jussieu, F-75252, Paris (France); Nikhef,Science Park 105, 1098 XG Amsterdam (Netherlands); Postma, Marieke; Vries, Jordy de [Nikhef,Science Park 105, 1098 XG Amsterdam (Netherlands)

2017-04-13

We calculate the cross-sections for the radiative formation of bound states by dark matter whose interactions are described in the non-relativistic regime by a Yukawa potential. These cross-sections are important for cosmological and phenomenological studies of dark matter with long-range interactions, residing in a hidden sector, as well as for TeV-scale WIMP dark matter. We provide the leading-order contributions to the cross-sections for the dominant capture processes occurring via emission of a vector or a scalar boson. We offer a detailed inspection of their features, including their velocity dependence within and outside the Coulomb regime, and their resonance structure. For pairs of annihilating particles, we compare bound-state formation with annihilation.

Hadron production in e+e- annihilation

International Nuclear Information System (INIS)

Lueth, V.

1977-01-01

The lectures cover recent results on hadron production by e + e - annihilation. Included are total hadronic cross section and scale invariance as applied to e + e - annihilation, the present status of the psi spectroscopy by study of the decay modes of the narrow psi resonances, and the recent discovery of charmed mesons. 93 references

Asymmetric dark matter annihilation as a test of non-standard cosmologies

International Nuclear Information System (INIS)

Gelmini, Graciela B.; Huh, Ji-Haeng; Rehagen, Thomas

2013-01-01

We show that the relic abundance of the minority component of asymmetric dark matter can be very sensitive to the expansion rate of the Universe and the temperature of transition between a non-standard pre-Big Bang Nucleosynthesis cosmological phase and the standard radiation dominated phase, if chemical decoupling happens before this transition. In particular, because the annihilation cross section of asymmetric dark matter is typically larger than that of symmetric dark matter in the standard cosmology, the decrease in relic density of the minority component in non-standard cosmologies with respect to the majority component may be compensated by the increase in annihilation cross section, so that the annihilation rate at present of asymmetric dark matter, contrary to general belief, could be larger than that of symmetric dark matter in the standard cosmology. Thus, if the annihilation cross section of the asymmetric dark matter candidate is known, the annihilation rate at present, if detectable, could be used to test the Universe before Big Bang Nucleosynthesis, an epoch from which we do not yet have any data

QCD in e+e- annihilation

International Nuclear Information System (INIS)

Ali, A.

1981-04-01

The promise of e + e - annihilation as an ideal laboratory to test Quantum Chromodynamics, QCD, has been the dominating theme in elementary particle physics during the last several years. An attempt is made to partially survey the subject in deep perturbative region in e + e - annihilation where theoretical ambiguities are minimal. Topics discussed include a review of the renormalization group methods relevant for e + e - annihilation, total hadronic cross section, jets and large-psub(T) phenomena, non-perturbative quark and gluon fragmentation effects and analysis of the jet distributions measured at DORIS, SPEAR and PETRA. My hope is to review realistic tests of QCD in e + e - annihilation - as opposed to the ultimate tests, which abound in literature. (orig.)

RZ calculations for self shielded multigroup cross sections

Energy Technology Data Exchange (ETDEWEB)

Li, M.; Sanchez, R.; Zmijarevic, I.; Stankovski, Z. [Commissariat a l' Energie Atomique CEA, Direction de l' Energie Nucleaire, DEN/DM2S/SERMA/LENR, 91191 Gif-sur-Yvette Cedex (France)

2006-07-01

A collision probability method has been implemented for RZ geometries. The method accounts for white albedo, specular and translation boundary condition on the top and bottom surfaces of the geometry and for a white albedo condition on the outer radial surface. We have applied the RZ CP method to the calculation of multigroup self shielded cross sections for Gadolinia absorbers in BWRs. (authors)

RZ calculations for self shielded multigroup cross sections

International Nuclear Information System (INIS)

Li, M.; Sanchez, R.; Zmijarevic, I.; Stankovski, Z.

2006-01-01

A collision probability method has been implemented for RZ geometries. The method accounts for white albedo, specular and translation boundary condition on the top and bottom surfaces of the geometry and for a white albedo condition on the outer radial surface. We have applied the RZ CP method to the calculation of multigroup self shielded cross sections for Gadolinia absorbers in BWRs. (authors)

Total cross section for hadron production by e+e--annihilation at center of mass energies between 3.6 and 5.2 GeV

International Nuclear Information System (INIS)

Brandelik, R.; Braunschweig, W.; Ludwig, J.; Mess, K.H.; Orito, S.; Suda, T.; Tokyo Univ.

1978-03-01

The total cross section for e + e - annihilation into hadronic final states between 3.6 and 5.2 GeV was measured by the nonmagnetic inner detector of DASP, which has similar trigger and detection efficeincies for photons and charged particles. The measured difference in R = sigmasub(had)/sigmasub(μμ) between 3.6 GeV and 5.2 GeV is ΔR = 2.1 +- 0.3. We observe three peaks at cm energies of 4.04, 4.16 and 4.417 GeV, the parameters of which, when interpreted as resonances, are given. (orig.) [de

Power spectrum tomography of dark matter annihilation with local galaxy distribution

Energy Technology Data Exchange (ETDEWEB)

Ando, Shin' ichiro, E-mail: s.ando@uva.nl [GRAPPA Institute, University of Amsterdam, 1098 XH Amsterdam (Netherlands)

2014-10-01

Cross-correlating the gamma-ray background with local galaxy catalogs potentially gives stringent constraints on dark matter annihilation. We provide updated theoretical estimates of sensitivities to the annihilation cross section from gamma-ray data with Fermi telescope and 2MASS galaxy catalogs, by elaborating the galaxy power spectrum and astrophysical backgrounds, and adopting the Markov-Chain Monte Carlo simulations. In particular, we show that taking tomographic approach by dividing the galaxy catalogs into more than one redshift slice will improve the sensitivity by a factor of a few to several. If dark matter halos contain lots of bright substructures, yielding a large annihilation boost (e.g., a factor of ∼100 for galaxy-size halos), then one may be able to probe the canonical annihilation cross section for thermal production mechanism up to masses of ∼700 GeV. Even with modest substructure boost (e.g., a factor of ∼10 for galaxy-size halos), on the other hand, the sensitivities could still reach a factor of three larger than the canonical cross section for dark matter masses of tens to a few hundreds of GeV.

Antiproton annihilation in very low-energy antihydrogen scattering by simple atoms and molecules

International Nuclear Information System (INIS)

Armour, E.A.G.; Gregory, M.R.; Liu, Y.

2006-01-01

The aim of experimentalists currently working on the preparation of antihydrogen is to trap it at very low temperatures so that its properties can be studied. Of concern to experimentalists are processes that lead to a loss of antihydrogen through annihilation. The dominant annihilation process that leads to the loss of antihydrogen is the annihilation of the antiproton with nuclei through the strong interaction. A recent scattering calculation of antihydrogen with hydrogen at very low energy, using the complex strong interaction potential of Kohno and Weise, has found an average annihilation cross-section of 0.13E -1/2 a 0 -2 , where E is the energy of relative motion. The antihydrogen-helium system is of particular interest to experimentalists as helium may be present as an impurity in the trap. Also there is interest in the possibility of using it to cool antihydrogen. We present a treatment of antihydrogen scattering with helium at very low temperatures. The annihilation cross-sections obtained are much larger than antihydrogen-hydrogen scattering cross-section, making it very unlikely that helium can be used to cool antihydrogen

X-ray lines and self-interacting dark matter.

Science.gov (United States)

Mambrini, Yann; Toma, Takashi

We study the correlation between a monochromatic signal from annihilating dark matter and its self-interacting cross section. We apply our argument to a complex scalar dark sector, where the pseudo-scalar plays the role of a warm dark matter candidate while the scalar mediates its interaction with the Standard Model. We combine the recent observation of the cluster Abell 3827 for self-interacting dark matter and the constraints on the annihilation cross section for monochromatic X-ray lines. We also confront our model to a set of recent experimental analyses and find that such an extension can naturally produce a monochromatic keV signal corresponding to recent observations of Perseus or Andromeda, while in the meantime it predicts a self-interacting cross section of the order of [Formula: see text], as recently claimed in the observation of the cluster Abell 3827. We also propose a way to distinguish such models by future direct detection techniques.

Background-cross-section-dependent subgroup parameters

International Nuclear Information System (INIS)

Yamamoto, Toshihisa

2003-01-01

A new set of subgroup parameters was derived that can reproduce the self-shielded cross section against a wide range of background cross sections. The subgroup parameters are expressed with a rational equation which numerator and denominator are expressed as the expansion series of background cross section, so that the background cross section dependence is exactly taken into account in the parameters. The advantage of the new subgroup parameters is that they can reproduce the self-shielded effect not only by group basis but also by subgroup basis. Then an adaptive method is also proposed which uses fitting procedure to evaluate the background-cross-section-dependence of the parameters. One of the simple fitting formula was able to reproduce the self-shielded subgroup cross section by less than 1% error from the precise evaluation. (author)

Fully double-logarithm-resummed cross sections

International Nuclear Information System (INIS)

Albino, S.; Bolzoni, P.; Kniehl, B.A.; Kotikov, A.

2011-01-01

We calculate the complete double logarithmic contribution to cross sections for semi-inclusive hadron production in the modified minimal-subtraction (MS-bar) scheme by applying dimensional regularization to the double logarithm approximation. The full double logarithmic contribution to the coefficient functions for inclusive hadron production in e + e - annihilation is obtained in this scheme for the first time. Our result agrees with all fixed order results in the literature, which extend to next-to-next-to-leading order.

Bonderenko self-shielded cross sections and multiband parameters derived from the LLL Evaluated-Nuclear-Data Library (ENDL)

International Nuclear Information System (INIS)

Cullen, D.E.

1978-01-01

Bonderenko self-shielded cross sections and multiband parameters from the Lawrence Livermore Laboratory Evaluated-Nuclear-Data Library (ENDL) as of July 4, 1978 are presented. These data include total, elastic, capture, and fission cross sections in the TART 175 group structure. Multiband parameters are listed. Bonderenko self-shielded cross section and the multiband parameters are presented on microfiche

Positron two-photon annihilation coincidence technique: difference mode

Energy Technology Data Exchange (ETDEWEB)

Karol, P J; Klobuchar, R L [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Chemistry

1978-05-01

A difference (or comparative) mode in the measurement of two-photon coincidences from positron or positronium annihilation has been developed. The method can be used to advantage, particularly in gases, in determining annihilation parameters such as quenching cross sections for low concentration strongly quenching chemical species in a reference medium which is relatively non-quenching.

CREST : a computer program for the calculation of composition dependent self-shielded cross-sections

International Nuclear Information System (INIS)

Kapil, S.K.

1977-01-01

A computer program CREST for the calculation of the composition and temperature dependent self-shielded cross-sections using the shielding factor approach has been described. The code includes the editing and formation of the data library, calculation of the effective shielding factors and cross-sections, a fundamental mode calculation to generate the neutron spectrum for the system which is further used to calculate the effective elastic removal cross-sections. Studies to explore the sensitivity of reactor parameters to changes in group cross-sections can also be carried out by using the facility available in the code to temporarily change the desired constants. The final self-shielded and transport corrected group cross-sections can be dumped on cards or magnetic tape in a suitable form for their direct use in a transport or diffusion theory code for detailed reactor calculations. The program is written in FORTRAN and can be accommodated in a computer with 32 K work memory. The input preparation details, sample problem and the listing of the program are given. (author)

Probing dark matter self-interaction in the Sun with IceCube-PINGU

International Nuclear Information System (INIS)

Chen, Chian-Shu; Lee, Fei-Fan; Lin, Guey-Lin; Lin, Yen-Hsun

2014-01-01

We study the capture, annihilation and evaporation of dark matter (DM) inside the Sun. It has been shown that the DM self-interaction can increase the DM number inside the Sun. We demonstrate that this enhancement becomes more significant in the regime of small DM mass, given a fixed DM self-interaction cross section. This leads to the enhancement of neutrino flux from DM annihilation. On the other hand, for DM mass as low as as a few GeVs, not only the DM-nuclei scatterings can cause the DM evaporation, DM self-interaction also provides non-negligible contributions to this effect. Consequently, the critical mass for DM evaporation (typically 3 ∼ 4 GeV without the DM self-interaction) can be slightly increased. We discuss the prospect of detecting DM self-interaction in IceCube-PINGU using the annihilation channels χχ → τ + τ - , νν-bar as examples. The PINGU sensitivities to DM self-interaction cross section σ χχ are estimated for track and cascade events

Antiproton annihilation in very low-energy antihydrogen scattering by simple atoms and molecules

Energy Technology Data Exchange (ETDEWEB)

Armour, E.A.G. [School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Gregory, M.R. [School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD (United Kingdom)]. E-mail: mark.gregory@maths.nottingham.ac.uk; Liu, Y. [School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

2006-06-15

The aim of experimentalists currently working on the preparation of antihydrogen is to trap it at very low temperatures so that its properties can be studied. Of concern to experimentalists are processes that lead to a loss of antihydrogen through annihilation. The dominant annihilation process that leads to the loss of antihydrogen is the annihilation of the antiproton with nuclei through the strong interaction. A recent scattering calculation of antihydrogen with hydrogen at very low energy, using the complex strong interaction potential of Kohno and Weise, has found an average annihilation cross-section of 0.13E{sup -1/2}a{sub 0}{sup -2}, where E is the energy of relative motion. The antihydrogen-helium system is of particular interest to experimentalists as helium may be present as an impurity in the trap. Also there is interest in the possibility of using it to cool antihydrogen. We present a treatment of antihydrogen scattering with helium at very low temperatures. The annihilation cross-sections obtained are much larger than antihydrogen-hydrogen scattering cross-section, making it very unlikely that helium can be used to cool antihydrogen.

On the inclusive annihilation of polarized e+e--pair with two observed hadrons

International Nuclear Information System (INIS)

Khachatryan, G.N.; Shakhnazaryan, Yu.G.

1976-01-01

The general consideration of the inclusive annihilation of polarized e + e - -pair with two observed hadrons in final state (e + e - →h 1 h 2 X) is carried out. The annihilation cross section is expressed in terms of five structure functions describing the transition γ*→h 1 h 2 X. The partial widths of the corresponding decay of a virtual photon for different polarizations of the photon are also introduced and the annihilation cross section is written through these widths. The density matrix of the virtual photon and its polarizational multipole moments are given as well

Cosmological constraints on dark matter annihilation and decay. Cross-correlation analysis of the extragalactic γ-ray background and cosmic shear

Energy Technology Data Exchange (ETDEWEB)

Shirasaki, Masato [National Astronomical Observatory of Japan, Mitaka, Tokyo (Japan); Macias, Oscar; Horiuchi, Shunsaku [Virginia Tech, Blacksburg, VA (United States). Center for Neutrino Physics; Shirai, Satoshi [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yoshida, Naoki [Tokyo Univ. (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli Inst. for the Physics and Mathematics of the Universe (WPI); Japan Science and Technology Agency, Saitama (Japan). CREST

2016-07-15

We derive constraints on dark matter (DM) annihilation cross section and decay lifetime from cross-correlation analyses of the data from Fermi-LAT and weak lensing surveys that cover a wide area of ∝660 squared degrees in total. We improve upon our previous analyses by using an updated extragalactic γ-ray background data reprocessed with the Fermi Pass 8 pipeline, and by using well-calibrated shape measurements of about twelve million galaxies in the Canada-France-Hawaii Lensing Survey (CFHTLenS) and Red-Cluster-Sequence Lensing Survey (RCSLenS). We generate a large set of full-sky mock catalogs from cosmological N-body simulations and use them to estimate statistical errors accurately. The measured cross correlation is consistent with null detection, which is then used to place strong cosmological constraints on annihilating and decaying DM. For leptophilic DM, the constraints are improved by a factor of ∝ 100 in the mass range of O(1) TeV when including contributions from secondary γ rays due to the inverse-Compton upscattering of background photons. Annihilation cross-sections of left angle σν right angle ∝ 10{sup -23} cm{sup 3}/s are excluded for TeV-scale DM depending on channel. Lifetimes of ∝10{sup 25} sec are also excluded for the decaying TeV-scale DM. Finally, we apply this analysis to wino DM and exclude the wino mass around 200 GeV. These constraints will be further tightened, and all the interesting wino DM parameter region can be tested, by using data from future wide-field cosmology surveys.

Cosmological constraints on dark matter annihilation and decay. Cross-correlation analysis of the extragalactic γ-ray background and cosmic shear

International Nuclear Information System (INIS)

Shirasaki, Masato; Macias, Oscar; Horiuchi, Shunsaku; Yoshida, Naoki; Tokyo Univ., Chiba; Japan Science and Technology Agency, Saitama

2016-07-01

We derive constraints on dark matter (DM) annihilation cross section and decay lifetime from cross-correlation analyses of the data from Fermi-LAT and weak lensing surveys that cover a wide area of ∝660 squared degrees in total. We improve upon our previous analyses by using an updated extragalactic γ-ray background data reprocessed with the Fermi Pass 8 pipeline, and by using well-calibrated shape measurements of about twelve million galaxies in the Canada-France-Hawaii Lensing Survey (CFHTLenS) and Red-Cluster-Sequence Lensing Survey (RCSLenS). We generate a large set of full-sky mock catalogs from cosmological N-body simulations and use them to estimate statistical errors accurately. The measured cross correlation is consistent with null detection, which is then used to place strong cosmological constraints on annihilating and decaying DM. For leptophilic DM, the constraints are improved by a factor of ∝ 100 in the mass range of O(1) TeV when including contributions from secondary γ rays due to the inverse-Compton upscattering of background photons. Annihilation cross-sections of left angle σν right angle ∝ 10"-"2"3 cm"3/s are excluded for TeV-scale DM depending on channel. Lifetimes of ∝10"2"5 sec are also excluded for the decaying TeV-scale DM. Finally, we apply this analysis to wino DM and exclude the wino mass around 200 GeV. These constraints will be further tightened, and all the interesting wino DM parameter region can be tested, by using data from future wide-field cosmology surveys.

Total cross section for hadron production by e+e- annihilation at PETRA energies

International Nuclear Information System (INIS)

Bartel, W.; Canzler, T.; Cords, D.; Dittmann, P.; Eichler, R.; Felst, R.; Godermann, E.; Haidt, D.; Kawabata, S.; Krehbiel, H.

1979-10-01

The cross section for the process e + e - → multihadrons has been measured at the highest PETRA energies. We measure R (the total cross-section in units of the point-like e + e - → μ + μ - cross-section) to be 2.9 +- 0.7, 4.0 +- 0.5, 4.6 +- 0.4 and 4.2 +- 0.6 at √s of 22, 27.7, 30 and 31.6 GeV respectively. The observed average multiplicity, together with existing low energy data, indicate a rapid increase in multiplicity with increasing energy. (orig.)

Dark matter annihilation into right-handed neutrinos and the galactic center gamma-ray excess

Energy Technology Data Exchange (ETDEWEB)

Tang, Yi-Lei [Center for High Energy Physics, Peking University,Beijing 100871 (China); Zhu, Shou-hua [Center for High Energy Physics, Peking University,Beijing 100871 (China); Institute of Theoretical Physics State Key Laboratory of Nuclear Physics and Technology,Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter,Beijing 100871 (China)

2016-03-08

In this paper, we will discuss a specific case that the dark matter particles annihilate into right-handed neutrinos. We calculate the predicted gamma-ray excess from the galactic center and compare our results with the data from the Fermi-LAT. An approximately 10–60 GeV right-handed neutrino with heavier dark matter particle can perfectly explain the observed spectrum. The annihilation cross section 〈σv〉 falls within the range 0.5–4×10{sup −26} cm{sup 3}/s, which is roughly compatible with the WIMP annihilation cross section.

ANTICOOL: Simulating positron cooling and annihilation in atomic gases

Science.gov (United States)

Green, D. G.

2018-03-01

The Fortran program ANTICOOL, developed to simulate positron cooling and annihilation in atomic gases for positron energies below the positronium-formation threshold, is presented. Given positron-atom elastic scattering phase shifts, normalised annihilation rates Zeff, and γ spectra as a function of momentum k, ANTICOOL enables the calculation of the positron momentum distribution f(k , t) as a function of time t, the time-varying normalised annihilation rate Z¯eff(t) , the lifetime spectrum and time-varying annihilation γ spectra. The capability and functionality of the program is demonstrated via a tutorial-style example for positron cooling and annihilation in room temperature helium gas, using accurate scattering and annihilation cross sections and γ spectra calculated using many-body theory as input.

Semi-inclusive production of two back-to-back hadron pairs in e+e- annihilation revisited

Science.gov (United States)

Matevosyan, Hrayr H.; Bacchetta, Alessandro; Boer, Daniël; Courtoy, Aurore; Kotzinian, Aram; Radici, Marco; Thomas, Anthony W.

2018-04-01

The cross section for back-to-back hadron pair production in e+e- annihilation provides access to the dihadron fragmentation functions (DiFF) needed to extract nucleon parton distribution functions from the semi-inclusive deep inelastic scattering (SIDIS) experiments with two detected final state hadrons. Particular attention is given to the so-called interference DiFF (IFF), which makes it possible to extract the transversity parton distribution of the nucleon in the collinear framework. However, previously unnoticed discrepancies were recently highlighted between the definitions of the IFFs appearing in the collinear kinematics when reconstructed from DiFFs entering the unintegrated fully differential cross sections of SIDIS and e+e- annihilation processes. In this work, to clarify this problem we re-derive the fully differential cross section for e+e- annihilation at the leading-twist approximation. We find a mistake in the definition of the kinematics in the original expression that systematically affects a subset of terms and that leads to two significant consequences. First, the discrepancy between the IFF definitions in the cross sections for SIDIS and e+e- annihilation is resolved. Second, the previously derived azimuthal asymmetry for accessing the helicity dependent DiFF G1⊥ in e+e- annihilation vanishes, which explains the nonobservation of this asymmetry in the recent experimental searches by the BELLE collaboration. We discuss the recently proposed alternative option to extract G1⊥.

Asymmetric thermal-relic dark matter. Sommerfeld-enhanced freeze-out, annihilation signals and unitarity bounds

International Nuclear Information System (INIS)

Baldes, Iason; Petraki, Kalliopi

2017-03-01

Dark matter that possesses a particle-antiparticle asymmetry and has thermalised in the early universe, requires a larger annihilation cross-section compared to symmetric dark matter, in order to deplete the dark antiparticles and account for the observed dark matter density. The annihilation cross-section determines the residual symmetric component of dark matter, which may give rise to annihilation signals during CMB and inside haloes today. We consider dark matter with long-range interactions, in particular dark matter coupled to a light vector or scalar force mediator. We compute the couplings required to attain a final antiparticle-to-particle ratio after the thermal freeze-out of the annihilation processes in the early universe, and then estimate the late-time annihilation signals. We show that, due to the Sommerfeld enhancement, highly asymmetric dark matter with long-range interactions can have a significant annihilation rate, potentially larger than symmetric dark matter of the same mass with contact interactions. We discuss caveats in this estimation, relating to the formation of stable bound states. Finally, we consider the non-relativistic partial-wave unitarity bound on the inelastic cross-section, we discuss why it can be realised only by long-range interactions, and showcase the importance of higher partial waves in this regime of large inelasticity. We derive upper bounds on the mass of symmetric and asymmetric thermal-relic dark matter for s-wave and p-wave annihilation, and exhibit how these bounds strengthen as the dark asymmetry increases.

Asymmetric thermal-relic dark matter: Sommerfeld-enhanced freeze-out, annihilation signals and unitarity bounds

Energy Technology Data Exchange (ETDEWEB)

Baldes, Iason [DESY, Notkestraße 85, Hamburg, D-22607 Germany (Germany); Petraki, Kalliopi, E-mail: iason.baldes@desy.de, E-mail: kpetraki@lpthe.jussieu.fr [Laboratoire de Physique Théorique et Hautes Energies (LPTHE), UMR 7589 CNRS and UPMC, 4 Place Jussieu, Paris, F-75252 France (France)

2017-09-01

Dark matter that possesses a particle-antiparticle asymmetry and has thermalised in the early universe, requires a larger annihilation cross-section compared to symmetric dark matter, in order to deplete the dark antiparticles and account for the observed dark matter density. The annihilation cross-section determines the residual symmetric component of dark matter, which may give rise to annihilation signals during CMB and inside haloes today. We consider dark matter with long-range interactions, in particular dark matter coupled to a light vector or scalar force mediator. We compute the couplings required to attain a final antiparticle-to-particle ratio after the thermal freeze-out of the annihilation processes in the early universe, and then estimate the late-time annihilation signals. We show that, due to the Sommerfeld enhancement, highly asymmetric dark matter with long-range interactions can have a significant annihilation rate, potentially larger than symmetric dark matter of the same mass with contact interactions. We discuss caveats in this estimation, relating to the formation of stable bound states. Finally, we consider the non-relativistic partial-wave unitarity bound on the inelastic cross-section, we discuss why it can be realised only by long-range interactions, and showcase the importance of higher partial waves in this regime of large inelasticity. We derive upper bounds on the mass of symmetric and asymmetric thermal-relic dark matter for s -wave and p -wave annihilation, and exhibit how these bounds strengthen as the dark asymmetry increases.

Asymmetric thermal-relic dark matter. Sommerfeld-enhanced freeze-out, annihilation signals and unitarity bounds

Energy Technology Data Exchange (ETDEWEB)

Baldes, Iason [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Petraki, Kalliopi [Nationaal Instuut voor Kernfysica en Hoge-Energiefysica (NIKHEF), Amsterdam (Netherlands); UMR 7589 CNRS et UPMC, Paris (France). Laboratoire de Physique Theorique et Hautes Energies (LPTHE)

2017-03-15

Dark matter that possesses a particle-antiparticle asymmetry and has thermalised in the early universe, requires a larger annihilation cross-section compared to symmetric dark matter, in order to deplete the dark antiparticles and account for the observed dark matter density. The annihilation cross-section determines the residual symmetric component of dark matter, which may give rise to annihilation signals during CMB and inside haloes today. We consider dark matter with long-range interactions, in particular dark matter coupled to a light vector or scalar force mediator. We compute the couplings required to attain a final antiparticle-to-particle ratio after the thermal freeze-out of the annihilation processes in the early universe, and then estimate the late-time annihilation signals. We show that, due to the Sommerfeld enhancement, highly asymmetric dark matter with long-range interactions can have a significant annihilation rate, potentially larger than symmetric dark matter of the same mass with contact interactions. We discuss caveats in this estimation, relating to the formation of stable bound states. Finally, we consider the non-relativistic partial-wave unitarity bound on the inelastic cross-section, we discuss why it can be realised only by long-range interactions, and showcase the importance of higher partial waves in this regime of large inelasticity. We derive upper bounds on the mass of symmetric and asymmetric thermal-relic dark matter for s-wave and p-wave annihilation, and exhibit how these bounds strengthen as the dark asymmetry increases.

Asymmetric thermal-relic dark matter: Sommerfeld-enhanced freeze-out, annihilation signals and unitarity bounds

International Nuclear Information System (INIS)

Baldes, Iason; Petraki, Kalliopi

2017-01-01

Dark matter that possesses a particle-antiparticle asymmetry and has thermalised in the early universe, requires a larger annihilation cross-section compared to symmetric dark matter, in order to deplete the dark antiparticles and account for the observed dark matter density. The annihilation cross-section determines the residual symmetric component of dark matter, which may give rise to annihilation signals during CMB and inside haloes today. We consider dark matter with long-range interactions, in particular dark matter coupled to a light vector or scalar force mediator. We compute the couplings required to attain a final antiparticle-to-particle ratio after the thermal freeze-out of the annihilation processes in the early universe, and then estimate the late-time annihilation signals. We show that, due to the Sommerfeld enhancement, highly asymmetric dark matter with long-range interactions can have a significant annihilation rate, potentially larger than symmetric dark matter of the same mass with contact interactions. We discuss caveats in this estimation, relating to the formation of stable bound states. Finally, we consider the non-relativistic partial-wave unitarity bound on the inelastic cross-section, we discuss why it can be realised only by long-range interactions, and showcase the importance of higher partial waves in this regime of large inelasticity. We derive upper bounds on the mass of symmetric and asymmetric thermal-relic dark matter for s -wave and p -wave annihilation, and exhibit how these bounds strengthen as the dark asymmetry increases.

Possible Dark Matter Annihilation Signal in the AMS-02 Antiproton Data.

Science.gov (United States)

Cui, Ming-Yang; Yuan, Qiang; Tsai, Yue-Lin Sming; Fan, Yi-Zhong

2017-05-12

Using the latest AMS-02 cosmic-ray antiproton flux data, we search for a potential dark matter annihilation signal. The background parameters about the propagation, source injection, and solar modulation are not assumed a priori but based on the results inferred from the recent B/C ratio and proton data measurements instead. The possible dark matter signal is incorporated into the model self-consistently under a Bayesian framework. Compared with the astrophysical background-only hypothesis, we find that a dark matter signal is favored. The rest mass of the dark matter particles is ∼20-80  GeV, and the velocity-averaged hadronic annihilation cross section is about (0.2-5)×10^{-26}  cm^{3} s^{-1}, in agreement with that needed to account for the Galactic center GeV excess and/or the weak GeV emission from dwarf spheroidal galaxies Reticulum 2 and Tucana III. Tight constraints on the dark matter annihilation models are also set in a wide mass region.

Isospin effects in anti p3He annihilation at rest

International Nuclear Information System (INIS)

Balestra, F.; Barbieri, R.; Batusov, Yu.A.; Bendiscioli, G.; Breivik, F.O.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Falomkin, I.V.; Ferrero, L.; Guaraldo, C.; Haatuft, A.; Halsteinslid, A.; Jacobsen, T.; Lodi Rizzini, E.; Maggiora, A.; Myklebost, K.; Olsen, J.M.; Panzieri, D.; Piragino, G.; Pontecorvo, G.B.; Rozhdestvensky, A.M.; Rotondi, A.; Salvini, P.; Sapozhnikov, M.G.; Soerensen, S.O.; Tosello, F.; Tretyak, V.I.; Venaglioni, A.; Zenoni, A.

1989-01-01

The analysis of anti p 3 He annihilation events at rest (from the PS 179 experiment at LEAR) gives the value 0.467±0.035 for the ratio between the annihilation cross sections on n and on p. This low value indicates a strong isospin dependence of the anti NN amplitude in P wave. (orig.)

Constraints on dark matter annihilation from CMB observations before Planck

Energy Technology Data Exchange (ETDEWEB)

Lopez-Honorez, Laura [Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Mena, Olga; Palomares-Ruiz, Sergio; Vincent, Aaron C., E-mail: llopezho@vub.ac.be, E-mail: omena@ific.uv.es, E-mail: sergio.palomares.ruiz@ist.utl.pt, E-mail: vincent@ific.uv.es [Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, E-46071 Valencia (Spain)

2013-07-01

We compute the bounds on the dark matter (DM) annihilation cross section using the most recent Cosmic Microwave Background measurements from WMAP9, SPT'11 and ACT'10. We consider DM with mass in the MeV–TeV range annihilating 100% into either an e{sup +}e{sup −} or a μ{sup +}μ{sup −} pair. We consider a realistic energy deposition model, which includes the dependence on the redshift, DM mass and annihilation channel. We exclude the canonical thermal relic abundance cross section ((σv) = 3 × 10{sup −26}cm{sup 3}s{sup −1}) for DM masses below 30 GeV and 15 GeV for the e{sup +}e{sup −} and μ{sup +}μ{sup −} channels, respectively. A priori, DM annihilating in halos could also modify the reionization history of the Universe at late times. We implement a realistic halo model taken from results of state-of-the-art N-body simulations and consider a mixed reionization mechanism, consisting on reionization from DM as well as from first stars. We find that the constraints on DM annihilation remain unchanged, even when large uncertainties on the halo model parameters are considered.

Pseudoscalar boson production in e+e- annihilation

International Nuclear Information System (INIS)

Grigoryan, S.G.; Chatrchyan, S.A.

1987-01-01

A mechanism of pseudoscalar boson production by the heavy quark-antiquark pair via one-photon exchange in e + e - annihilation is studied. The total cross sections of this reaction and energy distributions of produced p 0 -boson are obtained

URR [Unresolved Resonance Region] computer code: A code to calculate resonance neutron cross-section probability tables, Bondarenko self-shielding factors, and self-indication ratios for fissile and fertile nuclides

International Nuclear Information System (INIS)

Leal, L.C.; de Saussure, G.; Perez, R.B.

1990-01-01

The URR computer code has been developed to calculate cross-section probability tables, Bondarenko self-shielding factors, and self-indication ratios for fertile and fissile isotopes in the unresolved resonance region. Monte Carlo methods are utilized to select appropriate resonance parameters and to compute the cross sections at the desired reference energy. The neutron cross sections are calculated by the single-level Breit-Wigner formalism with s-, p-, and d-wave contributions. The cross-section probability tables are constructed by sampling by Doppler broadened cross-sections. The various self-shielding factors are computer numerically as Lebesgue integrals over the cross-section probability tables

Multiple gamma lines from semi-annihilation

International Nuclear Information System (INIS)

D'Eramo, Francesco; McCullough, Matthew; Thaler, Jesse

2013-01-01

Hints in the Fermi data for a 130 GeV gamma line from the galactic center have ignited interest in potential gamma line signatures of dark matter. Explanations of this line based on dark matter annihilation face a parametric tension since they often rely on large enhancements of loop-suppressed cross sections. In this paper, we pursue an alternative possibility that dark matter gamma lines could arise from ''semi-annihilation'' among multiple dark sector states. The semi-annihilation reaction ψ i ψ j → ψ k γ with a single final state photon is typically enhanced relative to ordinary annihilation ψ i ψ-bar i → γγ into photon pairs. Semi-annihilation allows for a wide range of dark matter masses compared to the fixed mass value required by annihilation, opening the possibility to explain potential dark matter signatures at higher energies. The most striking prediction of semi-annihilation is the presence of multiple gamma lines, with as many as order N 3 lines possible for N dark sector states, allowing for dark sector spectroscopy. A smoking gun signature arises in the simplest case of degenerate dark matter, where a strong semi-annihilation line at 130 GeV would be accompanied by a weaker annihilation line at 173 GeV. As a proof of principle, we construct two explicit models of dark matter semi-annihilation, one based on non-Abelian vector dark matter and the other based on retrofitting Rayleigh dark matter

Subtraction method of computing QCD jet cross sections at NNLO accuracy

Science.gov (United States)

Trócsányi, Zoltán; Somogyi, Gábor

2008-10-01

We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.

Subtraction method of computing QCD jet cross sections at NNLO accuracy

Energy Technology Data Exchange (ETDEWEB)

Trocsanyi, Zoltan [University of Debrecen and Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen P.O.Box 51 (Hungary)], E-mail: Zoltan.Trocsanyi@cern.ch; Somogyi, Gabor [University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)], E-mail: sgabi@physik.unizh.ch

2008-10-15

We present a general subtraction method for computing radiative corrections to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps needed to set up this subtraction scheme are the same as those used in next-to-leading order computations. However, all steps need non-trivial modifications, which we implement such that that those can be defined at any order in perturbation theory. We give a status report of the implementation of the method to computing jet cross sections in electron-positron annihilation at the next-to-next-to-leading order accuracy.

Dark matter annihilation with s-channel internal Higgsstrahlung

Energy Technology Data Exchange (ETDEWEB)

Kumar, Jason; Liao, Jiajun, E-mail: liaoj@hawaii.edu; Marfatia, Danny

2016-08-10

We study the scenario of fermionic dark matter that annihilates to standard model fermions through an s-channel axial vector mediator. We point out that the well-known chirality suppression of the annihilation cross section can be alleviated by s-channel internal Higgsstrahlung. The shapes of the cosmic ray spectra are identical to that of t-channel internal Higgsstrahlung in the limit of a heavy mediating particle. Unlike the general case of t-channel bremsstrahlung, s-channel Higgsstrahlung can be the dominant annihilation process even for Dirac dark matter. Since the s-channel mediator can be a standard model singlet, collider searches for the mediator are easily circumvented.

Dark matter annihilation with s-channel internal Higgsstrahlung

International Nuclear Information System (INIS)

Kumar, Jason; Liao, Jiajun; Marfatia, Danny

2016-01-01

We study the scenario of fermionic dark matter that annihilates to standard model fermions through an s-channel axial vector mediator. We point out that the well-known chirality suppression of the annihilation cross section can be alleviated by s-channel internal Higgsstrahlung. The shapes of the cosmic ray spectra are identical to that of t-channel internal Higgsstrahlung in the limit of a heavy mediating particle. Unlike the general case of t-channel bremsstrahlung, s-channel Higgsstrahlung can be the dominant annihilation process even for Dirac dark matter. Since the s-channel mediator can be a standard model singlet, collider searches for the mediator are easily circumvented.

Revisiting big-bang nucleosynthesis constraints on dark-matter annihilation

Energy Technology Data Exchange (ETDEWEB)

Kawasaki, Masahiro [Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa 277-8582 (Japan); Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa 277-8583 (Japan); Kohri, Kazunori [Theory Center, IPNS, KEK, Tsukuba 305-0801 (Japan); Sokendai, Tsukuba 305-0801 (Japan); Moroi, Takeo [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa 277-8583 (Japan); Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Takaesu, Yoshitaro, E-mail: takaesu@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)

2015-12-17

We study the effects of dark-matter annihilation during the epoch of big-bang nucleosynthesis on the primordial abundances of light elements. We improve the calculation of the light-element abundances by taking into account the effects of anti-nucleons emitted by the annihilation of dark matter and the interconversion reactions of neutron and proton at inelastic scatterings of energetic nucleons. Comparing the theoretical prediction of the primordial light-element abundances with the latest observational constraints, we derive upper bounds on the dark-matter pair-annihilation cross section. Implication to some of particle-physics models are also discussed.

Revisiting big-bang nucleosynthesis constraints on dark-matter annihilation

Directory of Open Access Journals (Sweden)

Masahiro Kawasaki

2015-12-01

Full Text Available We study the effects of dark-matter annihilation during the epoch of big-bang nucleosynthesis on the primordial abundances of light elements. We improve the calculation of the light-element abundances by taking into account the effects of anti-nucleons emitted by the annihilation of dark matter and the interconversion reactions of neutron and proton at inelastic scatterings of energetic nucleons. Comparing the theoretical prediction of the primordial light-element abundances with the latest observational constraints, we derive upper bounds on the dark-matter pair-annihilation cross section. Implication to some of particle-physics models are also discussed.

Study of $\\eta$ and $\\eta'$ Production in $\\overline{n}p$ Annihilations

CERN Document Server

Filippi, A; Botta, E; Bressani, Tullio; Calvo, D; Costa, S; D'Isep, F; Feliciello, A; Iazzi, F; Marcello, S; Minetti, B; Mirfakhraee, N; Balestra, F; Bussa, M P; Busso, L; Cerello, P G; Denisov, O Yu; Garfagnini, R; Grasso, A; Maggiora, A; Panzarasa, A; Panzieri, D; Tosello, F; Bertin, A; Bruschi, M; Capponi, M; De Castro, S; Donà, R; Galli, D; Giacobbe, B; Marconi, U; Massa, I; Piccinini, M; Poli, M; Semprini-Cesari, N; Spighi, R; Vagnoni, V M; Vecchi, S; Villa, M; Vitale, A; Zoccoli, A; Bianconi, A; Bonomi, G; Lodi-Rizzini, E; Venturelli, L; Zenoni, A; Cicalò, C; Masoni, A; Mauro, S; Puddu, G; Serci, S; Usai, G L; Gorchakov, O E; Prakhov, S N; Rozhdestvensky, A M; Sapozhnikov, M G; Tretyak, V I; Gianotti, P; Guaraldo, C; Lanaro, A; Lucherini, V; Petrascu, C; Ableev, V G; Vannucci, Luigi; Vedovato, G; Bendiscioli, G; Filippini, V; Fontana, A; Montagna, P; Rotondi, A; Salvini, P; Tessaro, S

1999-01-01

The annihilation fractions and cross sections for the np annihilation reaction in flight (~50-400 MeV/c) into eta pi /sup +/ and eta ' pi /sup +/ final states have been measured. The first ones follow the trend expected for P wave annihilations. From the ratios of the yields an evaluation of the pseudoscalar mixing angle in the standard form is possible. The value found shows that for pseudoscalar meson production from P wave the quark line rule is not grossly violated. (22 refs).

Measurement of Antiproton-proton Cross-Sections at Low Antiproton Momenta

CERN Multimedia

2002-01-01

The experiment is designed to measure four different cross sections in the momentum range 150~MeV/c to 600~MeV/c: 1)~~~~the differential elastic \\\\ \\\\ 2)~~~~the differential charge exchange\\\\ \\\\ 3)~~~~the annihilation into charged and neutral pions\\\\ \\\\ 4)~~~~and the total cross section via the optical theorem. \\\\ \\\\ The experiment allows one to search once again and with good precision for baryonium. Of special interest is the existence of the S-meson, for which a signal of about 20~MeV-mb was found in a 1981 experiment (performed in the East Hall).\\\\ \\\\ A second point of special interest is the momentum region below 300~MeV/c because the cross sections are basically unknown. We will be able to explore the momentum dependence of this region for the first time.\\\\ \\\\ The elastic cross section is measured by a cylindrical multiwire proportional chamber and a scintillator hodoscope placed around a scattering chamber under vacuum. The charge exchange cross section is measured by a ring of 32~anti-neutron detector...

First search for dark matter annihilations in the Earth with the IceCube detector

International Nuclear Information System (INIS)

Aartsen, M.G.; Hill, G.C.; Robertson, S.; Wallace, A.; Whelan, B.J.; Abraham, K.; Bernhard, A.; Coenders, S.; Holzapfel, K.; Huber, M.; Jurkovic, M.; Krings, K.; Resconi, E.; Turcati, A.; Veenkamp, J.; Ackermann, M.; Bernardini, E.; Blot, S.; Bretz, H.P.; Franckowiak, A.; Gluesenkamp, T.; Jacobi, E.; Karg, T.; Kintscher, T.; Kunwar, S.; Mohrmann, L.; Nahnhauer, R.; Satalecka, K.; Spiering, C.; Stasik, A.; Stoessl, A.; Strotjohann, N.L.; Terliuk, A.; Usner, M.; Santen, J. van; Yanez, J.P.; Adams, J.; Aguilar, J.A.; Ansseau, I.; Heereman, D.; Meagher, K.; Meures, T.; O'Murchadha, A.; Pinat, E.; Raab, C.; Ahlers, M.; Braun, J.; Chirkin, D.; Day, M.; Desiati, P.; Diaz-Velez, J.C.; Fahey, S.; Feintzeig, J.; Ghorbani, K.; Gladstone, L.; Griffith, Z.; Halzen, F.; Hanson, K.; Jero, K.; Karle, A.; Kauer, M.; Kelley, J.L.; Kheirandish, A.; Krueger, C.; Mancina, S.; McNally, F.; Merino, G.; Sabbatini, L.; Tobin, M.N.; Tosi, D.; Vandenbroucke, J.; Rossem, M. van; Wandkowsky, N.; Wendt, C.; Westerhoff, S.; Wille, L.; Xu, D.L.; Ahrens, M.; Bohm, C.; Dumm, J.P.; Finley, C.; Flis, S.; Hultqvist, K.; Walck, C.; Wolf, M.; Zoll, M.; Altmann, D.; Anton, G.; Katz, U.; Kittler, T.; Tselengidou, M.; Andeen, K.; Anderson, T.; Dunkman, M.; Eller, P.; Huang, F.; Keivani, A.; Lanfranchi, J.L.; Pankova, D.V.; Quinnan, M.; Tesic, G.; Weiss, M.J.; Archinger, M.; Baum, V.; Boeser, S.; Pino Rosendo, E. del; Di Lorenzo, V.; Eberhardt, B.; Ehrhardt, T.; Foesig, C.C.; Koepke, L.; Krueckl, G.; Peiffer, P.; Sandroos, J.; Steuer, A.; Wiebe, K.; Argueelles, C.; Axani, S.; Collin, G.H.; Conrad, J.M.; Jones, B.J.P.; Moulai, M.; Auffenberg, J.; Bissok, M.; Glagla, M.; Glauch, T.; Haack, C.; Hansmann, B.; Hansmann, T.; Kemp, J.; Konietz, R.; Leuermann, M.; Leuner, J.; Penek, Oe.; Raedel, L.; Reimann, R.; Rongen, M.; Schimp, M.; Schoenen, S.; Schumacher, L.; Stahlberg, M.; Stettner, J.; Vehring, M.; Vogel, E.; Wallraff, M.; Wickmann, S.; Wiebusch, C.H.; Bai, X.; Barwick, S.W.; Yodh, G.; Bay, R.; Filimonov, K.; Price, P.B.; Woschnagg, K.; Beatty, J.J.; Becker Tjus, J.; Bos, F.; Eichmann, B.; Kroll, M.; Mandelartz, M.; Schoeneberg, S.; Tenholt, F.; Becker, K.H.; Bindig, D.; Helbing, K.; Hickford, S.; Hoffmann, R.; Kopper, S.; Lauber, F.; Naumann, U.; Obertacke Pollmann, A.; Soldin, D.; BenZvi, S.; Cross, R.; Berley, D.; Blaufuss, E.; Cheung, E.; Felde, J.; Friedman, E.; Hellauer, R.; Hoffman, K.D.; Maunu, R.; Olivas, A.; Schmidt, T.; Song, M.; Sullivan, G.W.; Besson, D.Z.; Binder, G.; Gerhardt, L.; Klein, S.R.; Miarecki, S.; Tatar, J.

2017-01-01

We present the results of the first IceCube search for dark matter annihilation in the center of the Earth. Weakly interacting massive particles (WIMPs), candidates for dark matter, can scatter off nuclei inside the Earth and fall below its escape velocity. Over time the captured WIMPs will be accumulated and may eventually self-annihilate. Among the annihilation products only neutrinos can escape from the center of the Earth. Large-scale neutrino telescopes, such as the cubic kilometer IceCube Neutrino Observatory located at the South Pole, can be used to search for such neutrino fluxes. Data from 327 days of detector livetime during 2011/2012 were analyzed. No excess beyond the expected background from atmospheric neutrinos was detected. The derived upper limits on the annihilation rate of WIMPs in the Earth and the resulting muon flux are an order of magnitude stronger than the limits of the last analysis performed with data from IceCube's predecessor AMANDA. The limits can be translated in terms of a spin-independent WIMP-nucleon cross section. For a WIMP mass of 50 GeV this analysis results in the most restrictive limits achieved with IceCube data. (orig.)

First search for dark matter annihilations in the Earth with the IceCube detector

Energy Technology Data Exchange (ETDEWEB)

Aartsen, M.G.; Hill, G.C.; Robertson, S.; Wallace, A.; Whelan, B.J. [University of Adelaide, Department of Physics, Adelaide (Australia); Abraham, K.; Bernhard, A.; Coenders, S.; Holzapfel, K.; Huber, M.; Jurkovic, M.; Krings, K.; Resconi, E.; Turcati, A.; Veenkamp, J. [Technische Universitaet Muenchen, Physik-Department, Garching (Germany); Ackermann, M.; Bernardini, E.; Blot, S.; Bretz, H.P.; Franckowiak, A.; Gluesenkamp, T.; Jacobi, E.; Karg, T.; Kintscher, T.; Kunwar, S.; Mohrmann, L.; Nahnhauer, R.; Satalecka, K.; Spiering, C.; Stasik, A.; Stoessl, A.; Strotjohann, N.L.; Terliuk, A.; Usner, M.; Santen, J. van; Yanez, J.P. [DESY, Zeuthen (Germany); Adams, J. [University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch (New Zealand); Aguilar, J.A.; Ansseau, I.; Heereman, D.; Meagher, K.; Meures, T.; O' Murchadha, A.; Pinat, E.; Raab, C. [Universite Libre de Bruxelles, Science Faculty CP230, Brussels (Belgium); Ahlers, M.; Braun, J.; Chirkin, D.; Day, M.; Desiati, P.; Diaz-Velez, J.C.; Fahey, S.; Feintzeig, J.; Ghorbani, K.; Gladstone, L.; Griffith, Z.; Halzen, F.; Hanson, K.; Jero, K.; Karle, A.; Kauer, M.; Kelley, J.L.; Kheirandish, A.; Krueger, C.; Mancina, S.; McNally, F.; Merino, G.; Sabbatini, L.; Tobin, M.N.; Tosi, D.; Vandenbroucke, J.; Rossem, M. van; Wandkowsky, N.; Wendt, C.; Westerhoff, S.; Wille, L.; Xu, D.L. [University of Wisconsin, Department of Physics and Wisconsin IceCube Particle Astrophysics Center, Madison, WI (United States); Ahrens, M.; Bohm, C.; Dumm, J.P.; Finley, C.; Flis, S.; Hultqvist, K.; Walck, C.; Wolf, M.; Zoll, M. [Stockholm University, Department of Physics, Oskar Klein Centre, Stockholm (Sweden); Altmann, D.; Anton, G.; Katz, U.; Kittler, T.; Tselengidou, M. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Centre for Astroparticle Physics, Erlangen (Germany); Andeen, K. [Marquette University, Department of Physics, Milwaukee, WI (United States); Anderson, T.; Dunkman, M.; Eller, P.; Huang, F.; Keivani, A.; Lanfranchi, J.L.; Pankova, D.V.; Quinnan, M.; Tesic, G.; Weiss, M.J. [Pennsylvania State University, Department of Physics, University Park, PA (United States); Archinger, M.; Baum, V.; Boeser, S.; Pino Rosendo, E. del; Di Lorenzo, V.; Eberhardt, B.; Ehrhardt, T.; Foesig, C.C.; Koepke, L.; Krueckl, G.; Peiffer, P.; Sandroos, J.; Steuer, A.; Wiebe, K. [University of Mainz, Institute of Physics, Mainz (Germany); Argueelles, C.; Axani, S.; Collin, G.H.; Conrad, J.M.; Jones, B.J.P.; Moulai, M. [Massachusetts Institute of Technology, Department of Physics, Cambridge, MA (United States); Auffenberg, J.; Bissok, M.; Glagla, M.; Glauch, T.; Haack, C.; Hansmann, B.; Hansmann, T.; Kemp, J.; Konietz, R.; Leuermann, M.; Leuner, J.; Penek, Oe.; Raedel, L.; Reimann, R.; Rongen, M.; Schimp, M.; Schoenen, S.; Schumacher, L.; Stahlberg, M.; Stettner, J.; Vehring, M.; Vogel, E.; Wallraff, M.; Wickmann, S.; Wiebusch, C.H. [RWTH Aachen University, III. Physikalisches Institut, Aachen (Germany); Bai, X. [South Dakota School of Mines and Technology, Physics Department, Rapid City, SD (United States); Barwick, S.W.; Yodh, G. [University of California, Department of Physics and Astronomy, Irvine, CA (United States); Bay, R.; Filimonov, K.; Price, P.B.; Woschnagg, K. [University of California, Department of Physics, Berkeley, CA (United States); Beatty, J.J. [Ohio State University, Department of Physics and Center for Cosmology and Astro-Particle Physics, Columbus, OH (United States); Ohio State University, Department of Astronomy, Columbus, OH (United States); Becker Tjus, J.; Bos, F.; Eichmann, B.; Kroll, M.; Mandelartz, M.; Schoeneberg, S.; Tenholt, F. [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Bochum (Germany); Becker, K.H.; Bindig, D.; Helbing, K.; Hickford, S.; Hoffmann, R.; Kopper, S.; Lauber, F.; Naumann, U.; Obertacke Pollmann, A.; Soldin, D. [University of Wuppertal, Department of Physics, Wuppertal (Germany); BenZvi, S.; Cross, R. [University of Rochester, Department of Physics and Astronomy, Rochester, NY (United States); Berley, D.; Blaufuss, E.; Cheung, E.; Felde, J.; Friedman, E.; Hellauer, R.; Hoffman, K.D.; Maunu, R.; Olivas, A.; Schmidt, T.; Song, M.; Sullivan, G.W. [University of Maryland, Department of Physics, College Park, MD (United States); Besson, D.Z. [University of Kansas, Department of Physics and Astronomy, Lawrence, KS (United States); Binder, G.; Gerhardt, L.; Klein, S.R.; Miarecki, S.; Tatar, J. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Collaboration: IceCube Collaboration; and others

2017-02-15

We present the results of the first IceCube search for dark matter annihilation in the center of the Earth. Weakly interacting massive particles (WIMPs), candidates for dark matter, can scatter off nuclei inside the Earth and fall below its escape velocity. Over time the captured WIMPs will be accumulated and may eventually self-annihilate. Among the annihilation products only neutrinos can escape from the center of the Earth. Large-scale neutrino telescopes, such as the cubic kilometer IceCube Neutrino Observatory located at the South Pole, can be used to search for such neutrino fluxes. Data from 327 days of detector livetime during 2011/2012 were analyzed. No excess beyond the expected background from atmospheric neutrinos was detected. The derived upper limits on the annihilation rate of WIMPs in the Earth and the resulting muon flux are an order of magnitude stronger than the limits of the last analysis performed with data from IceCube's predecessor AMANDA. The limits can be translated in terms of a spin-independent WIMP-nucleon cross section. For a WIMP mass of 50 GeV this analysis results in the most restrictive limits achieved with IceCube data. (orig.)

Bounds on Dark Matter annihilations from 21 cm data arXiv

CERN Document Server

D'Amico, Guido; Strumia, Alessandro

The observation of an absorption feature in the 21 cm spectrum at redshift $z\\approx 17$ implies bounds on Dark Matter annihilations for a broad range of masses, given that significant heating of the intergalactic medium would have erased such feature. The resulting bounds on the DM annihilation cross sections are comparable to the strongest ones from all other observables.

Relic density and CMB constraints on dark matter annihilation with Sommerfeld enhancement

International Nuclear Information System (INIS)

Zavala, Jesus; White, Simon D. M.; Vogelsberger, Mark

2010-01-01

We calculate how the relic density of dark matter particles is altered when their annihilation is enhanced by the Sommerfeld mechanism due to a Yukawa interaction between the annihilating particles. Maintaining a dark matter abundance consistent with current observational bounds requires the normalization of the s-wave annihilation cross section to be decreased compared to a model without enhancement. The level of suppression depends on the specific parameters of the particle model, with the kinetic decoupling temperature having the most effect. We find that the cross section can be reduced by as much as an order of magnitude for extreme cases. We also compute the μ-type distortion of the CMB energy spectrum caused by energy injection from such Sommerfeld-enhanced annihilation. Our results indicate that in the vicinity of resonances, associated with bound states, distortions can be large enough to be excluded by the upper limit |μ|≤9.0x10 -5 found by the FIRAS (Far Infrared Absolute Spectrophotometer) instrument on the COBE (Cosmic Background Explorer) satellite.

Constraining dark matter late-time energy injection: decays and p-wave annihilations

Energy Technology Data Exchange (ETDEWEB)

Diamanti, Roberta; Mena, Olga; Palomares-Ruiz, Sergio; Vincent, Aaron C. [Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, E-46071 Valencia (Spain); Lopez-Honorez, Laura, E-mail: R.Diamanti@uva.nl, E-mail: llopezho@vub.ac.be, E-mail: omena@ific.uv.es, E-mail: sergio.palomares.ruiz@ific.uv.es, E-mail: vincent@ific.uv.es [Theoretische Natuurkunde Vrije Universiteit Brussel and The International Solvay Institutes Pleinlaan 2, B-1050 Brussels (Belgium)

2014-02-01

We use the latest cosmic microwave background (CMB) observations to provide updated constraints on the dark matter lifetime as well as on p-wave suppressed annihilation cross sections in the 1 MeV to 1 TeV mass range. In contrast to scenarios with an s-wave dominated annihilation cross section, which mainly affect the CMB close to the last scattering surface, signatures associated with these scenarios essentially appear at low redshifts (z∼<50) when structure began to form, and thus manifest at lower multipoles in the CMB power spectrum. We use data from Planck, WMAP9, SPT and ACT, as well as Lyman–α measurements of the matter temperature at z ∼ 4 to set a 95% confidence level lower bound on the dark matter lifetime of ∼ 4 × 10{sup 25} s for m{sub χ} = 100 MeV. This bound becomes lower by an order of magnitude at m{sub χ} = 1 TeV due to inefficient energy deposition into the intergalactic medium. We also show that structure formation can enhance the effect of p-wave suppressed annihilation cross sections by many orders of magnitude with respect to the background cosmological rate, although even with this enhancement, CMB constraints are not yet strong enough to reach the thermal relic value of the cross section.

Searching for Dark Matter Annihilation in the Smith High-Velocity Cloud

Science.gov (United States)

Drlica-Wagner, Alex; Gomez-Vargas, German A.; Hewitt, John W.; Linden, Tim; Tibaldo, Luigi

2014-01-01

Recent observations suggest that some high-velocity clouds may be confined by massive dark matter halos. In particular, the proximity and proposed dark matter content of the Smith Cloud make it a tempting target for the indirect detection of dark matter annihilation. We argue that the Smith Cloud may be a better target than some Milky Way dwarf spheroidal satellite galaxies and use gamma-ray observations from the Fermi Large Area Telescope to search for a dark matter annihilation signal. No significant gamma-ray excess is found coincident with the Smith Cloud, and we set strong limits on the dark matter annihilation cross section assuming a spatially extended dark matter profile consistent with dynamical modeling of the Smith Cloud. Notably, these limits exclude the canonical thermal relic cross section (approximately 3 x 10 (sup -26) cubic centimeters per second) for dark matter masses less than or approximately 30 gigaelectronvolts annihilating via the B/B- bar oscillation or tau/antitau channels for certain assumptions of the dark matter density profile; however, uncertainties in the dark matter content of the Smith Cloud may significantly weaken these constraints.

Searching for dark matter annihilation in the Smith high-velocity cloud

International Nuclear Information System (INIS)

Drlica-Wagner, Alex; Gómez-Vargas, Germán A.; Hewitt, John W.; Linden, Tim; Tibaldo, Luigi

2014-01-01

Recent observations suggest that some high-velocity clouds may be confined by massive dark matter halos. In particular, the proximity and proposed dark matter content of the Smith Cloud make it a tempting target for the indirect detection of dark matter annihilation. We argue that the Smith Cloud may be a better target than some Milky Way dwarf spheroidal satellite galaxies and use γ-ray observations from the Fermi Large Area Telescope to search for a dark matter annihilation signal. No significant γ-ray excess is found coincident with the Smith Cloud, and we set strong limits on the dark matter annihilation cross section assuming a spatially extended dark matter profile consistent with dynamical modeling of the Smith Cloud. Notably, these limits exclude the canonical thermal relic cross section (∼ 3 × 10 –26 cm 3 s –1 ) for dark matter masses ≲ 30 GeV annihilating via the b b-bar or τ + τ – channels for certain assumptions of the dark matter density profile; however, uncertainties in the dark matter content of the Smith Cloud may significantly weaken these constraints.

Searching for dark matter annihilation in the Smith high-velocity cloud

Energy Technology Data Exchange (ETDEWEB)

Drlica-Wagner, Alex [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Gómez-Vargas, Germán A. [Departamento de Fisíca, Pontificia Universidad Católica de Chile, Avenida Vicuña Mackenna 4860, Santiago (Chile); Hewitt, John W. [CRESST, University of Maryland, Baltimore County, Baltimore, MD 21250 (United States); Linden, Tim [The Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Tibaldo, Luigi [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)

2014-07-20

Recent observations suggest that some high-velocity clouds may be confined by massive dark matter halos. In particular, the proximity and proposed dark matter content of the Smith Cloud make it a tempting target for the indirect detection of dark matter annihilation. We argue that the Smith Cloud may be a better target than some Milky Way dwarf spheroidal satellite galaxies and use γ-ray observations from the Fermi Large Area Telescope to search for a dark matter annihilation signal. No significant γ-ray excess is found coincident with the Smith Cloud, and we set strong limits on the dark matter annihilation cross section assuming a spatially extended dark matter profile consistent with dynamical modeling of the Smith Cloud. Notably, these limits exclude the canonical thermal relic cross section (∼ 3 × 10{sup –26} cm{sup 3} s{sup –1}) for dark matter masses ≲ 30 GeV annihilating via the b b-bar or τ{sup +}τ{sup –} channels for certain assumptions of the dark matter density profile; however, uncertainties in the dark matter content of the Smith Cloud may significantly weaken these constraints.

MINX, Multigroup Cross-Sections and Self-Shielding Factors from ENDF/B for Program SPHINX

International Nuclear Information System (INIS)

Soran, P.D.; MacFarlane, R.E.; Harris, D.R.; LaBauve, R.J.; Hendricks, J.S.; Kidman, R.B.; Weisbin, C.R.; White, J.E.

1977-01-01

1 - Description of problem or function: MINX calculates fine-group averaged infinitely diluted cross sections and self-shielding factors from ENDF/B-IV data. Its primary purpose is to generate a pseudo-composition-independent multigroup library which is input to the SPHINX space-energy collapse program (2) (PSR-0129) through standard CCCC-III (8) interfaces. MINX incorporates and improves upon the resonance capabilities of existing codes such as ETOX (5) (NESC0388) and ENDRUN (9) and the high-order group-to-group transfer matrices of SUPERTOG (10) (PSR-0013) and ETOG (11). Fine group energy boundaries, Legendre expansion order, gross spectral shape component (in the Bondarenko flux model), temperatures and dilutions can all be used specifically. 2 - Method of solution: Infinitely dilute, un-broadened point cross sections are obtained from resolved resonance parameters using a modified version of the RESEND program (3) (NESC0465). The SIGMA1 (4) (IAEA0854) kernel-broadening method is used to Doppler broaden and thin the tabulated linearized pointwise cross sections at 0 K (outside of the unresolved energy region). Effective temperature- dependent self-shielded pointwise cross sections are derived from the formulation in the ETOX code. The primary modification to the ETOX algorithm is associated with the numerical quadrature scheme used to establish the mean values of the fluctuation intervals. The selection of energy mesh points, at which the effective cross sections are calculated, has been modified to include the energy points given in the ENDF/B file or, if the energy-independent formalism was employed, points at half-lethargy intervals. Infinitely dilute group cross sections and self-shielding factors are generated using the Bondarenko flux weighting model with the gross spectral shape under user control. The integral over energy for each group is divided into a set of panels defined by the union of the grid points describing the total cross section, the

Prospects for discovering a neutrino line induced by dark matter annihilation

Energy Technology Data Exchange (ETDEWEB)

Aisati, Chaimae El; Garcia-Cely, Camilo; Hambye, Thomas; Vanderheyden, Laurent, E-mail: Chaimae.El.Aisati@ulb.ac.be, E-mail: Camilo.Alfredo.Garcia.Cely@ulb.ac.be, E-mail: thambye@ulb.ac.be, E-mail: laurent.vanderheyden@ulb.ac.be [Service de Physique Théorique—Université Libre de Bruxelles, Boulevard du Triomphe, CP225, 1050 Brussels (Belgium)

2017-10-01

In the near future, neutrino telescopes are expected to improve their sensitivity to the flux of monochromatic neutrinos produced by dark matter (DM) in our galaxy. This is illustrated by a new limit on the corresponding cross section that we derive from public IceCube data. In this context, we study which DM models could produce an observable flux of monochromatic neutrinos from DM annihilations. To this end, we proceed in two steps. First, within a set of simple and minimal assumptions concerning the properties of the DM particle, we determine the models that could give rise to a significant annihilation into monochromatic neutrinos at the freeze-out epoch. The list of models turns out to be very limited as a result of various constraints, in particular direct detection and neutrino masses at loop level. Given the fact that, even if largely improved, the sensitivities will be far from reaching the thermal annihilation cross section soon, a signal could only be observed if the annihilation into neutrinos today is boosted with respect to the freeze-out epoch. This is why, in a second step, we analyze the possibility of having such a large enhancement from the Sommerfeld effect. For each scenario, we also compute the cross sections into other annihilation products and confront our results with experimental constraints. We find that, within our simple and minimal assumptions, the expectation to observe monochromatic neutrinos is only possible in very specific scenarios. Some will be confirmed or excluded in the near future because they predict signals slightly below the current experimental sensitivities. We also discuss how these prospects change by relaxing our assumptions as well as by considering other types of sharp spectral features. For the latter, we consider boxed-shaped and bremsstrahlung spectra and provide the corresponding limits from IceCube data.

Cross-sectional anatomy for computed tomography

International Nuclear Information System (INIS)

Farkas, M.L.

1988-01-01

This self-study guide recognizes that evaluation and interpretation of CT-images demands a firm understanding of both cross-sectional anatomy and the principles of computed tomography. The objectives of this book are: to discuss the basic principles of CT, to stress the importance of cross-sectional anatomy to CT through study of selected cardinal transverse sections of head, neck, and trunk, to explain orientation and interpretation of CT-images with the aid of corresponding cross-sectional preparations

URR [Unresolved Resonance Region] computer code: A code to calculate resonance neutron cross-section probability tables, Bondarenko self-shielding factors, and self-indication ratios for fissile and fertile nuclides

International Nuclear Information System (INIS)

Leal, L.C.; de Saussure, G.; Perez, R.B.

1989-01-01

The URR computer code has been developed to calculate cross-section probability tables, Bondarenko self-shielding factors, and self- indication ratios for fertile and fissile isotopes in the unresolved resonance region. Monte Carlo methods are utilized to select appropriate resonance parameters and to compute the cross sections at the desired reference energy. The neutron cross sections are calculated by the single-level Breit-Wigner formalism with s-, p-, and d-wave contributions. The cross-section probability tables are constructed by sampling the Doppler broadened cross-section. The various shelf-shielded factors are computed numerically as Lebesgue integrals over the cross-section probability tables. 6 refs

Annihilation of antiproton on deuteron at rest

International Nuclear Information System (INIS)

Grach, I.; Shmatikov, M.

1982-01-01

The system of Faddeev equations for amplitudes of anti pD iteraction at rest accounting for higher partial anti NN waves is derived. From its solution the total and elastic anti pD cross sections are calculated. Predictions for the missing-mass spectrum in the anti pD annihilation are made. The P-wave anti NN states give small contribution to the anti pD cross section at rest, the theoretical value of the latter being less than the experimental cross section extrapolated to the threshold. Let us emphasize that the total anti pD cross section depending weakly on the radii of anti NN interactions is sensitive to the values of the anti NN scattering lengths. Experimental data for anti pD cross sections at rest can be obtained only by extrapolation procedure. Henceforth it is very important to investigate the anti pD interactions at low but non-zero momenta where the direct comparison to the experiment is possible [ru

Connecting dark matter annihilation to the vertex functions of Standard Model fermions

Energy Technology Data Exchange (ETDEWEB)

Kumar, Jason; Light, Christopher, E-mail: jkumar@hawaii.edu, E-mail: lightc@hawaii.edu [Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822, Hawaii (United States)

2017-07-01

We consider scenarios in which dark matter is a Majorana fermion which couples to Standard Model fermions through the exchange of charged mediating particles. The matrix elements for various dark matter annihilation processes are then related to one-loop corrections to the fermion-photon vertex, where dark matter and the charged mediators run in the loop. In particular, in the limit where Standard Model fermion helicity mixing is suppressed, the cross section for dark matter annihilation to various final states is related to corrections to the Standard Model fermion charge form factor. These corrections can be extracted in a gauge-invariant manner from collider cross sections. Although current measurements from colliders are not precise enough to provide useful constraints on dark matter annihilation, improved measurements at future experiments, such as the International Linear Collider, could improve these constraints by several orders of magnitude, allowing them to surpass the limits obtainable by direct observation.

Violation of G-parity in antinucleon-nucleon annihilation

International Nuclear Information System (INIS)

Green, A.M.; Sainio, M.E.; Moussallam, B.; Niskanen, J.A.; Wycech, S.

1991-01-01

A strategy is proposed for investigating the violation of G-parity in the annihilation reaction anti np → π + π 0 . As illustrations π 0 -η mixing and the mass difference effects are considered. This leads to an asymmetry of about 1% in the cross section. (orig.)

Cross-sectional nanophotoluminescence studies of Stark effects in self-assembled quantum dots

International Nuclear Information System (INIS)

Htoon, H.; Keto, J. W.; Baklenov, O.; Holmes, A. L. Jr.; Shih, C. K.

2000-01-01

By using a cross-sectional geometry, we show the capability to perform single-dot spectroscopy in self-assembled quantum dots using far-field optics. By using this method, we study the quantum-confined Stark effect in self-assembled quantum dots. For single-stack quantum dots (QDs), we find that the spectra are redshifted with an increase in electric field. For vertically coupled double-stack quantum dots, while most of the QDs are redshifted, some QDs show blueshifted spectra, which can be interpreted as an evidence of coupled QD molecules. (c) 2000 American Institute of Physics

The Self-esteem Stability Scale (SESS) for Cross-Sectional Direct Assessment of Self-esteem Stability.

Science.gov (United States)

Altmann, Tobias; Roth, Marcus

2018-01-01

Self-esteem stability describes fluctuations in the level of self-esteem experienced by individuals over a brief period of time. In recent decades, self-esteem stability has repeatedly been shown to be an important variable affecting psychological functioning. However, measures of self-esteem stability are few and lacking in validity. In this paper, we present the Self-Esteem Stability Scale (SESS), a unidimensional and very brief scale to directly assess self-esteem stability. In four studies (total N = 826), we describe the development of the SESS and present evidence for its validity with respect to individual outcomes (life satisfaction, neuroticism, and vulnerable narcissism) and dyadic outcomes (relationship satisfaction in self- and partner ratings) through direct comparisons with existing measures. The new SESS proved to be a stronger predictor than the existing scales and had incremental validity over and above self-esteem level. The results also showed that all cross-sectional measures of self-esteem stability were only moderately associated with variability in self-esteem levels assessed longitudinally with multiple administrations of the Rosenberg Self-Esteem Scale. We discuss this validity issue, arguing that direct and indirect assessment approaches measure relevant, yet different aspects of self-esteem stability.

The Self-esteem Stability Scale (SESS) for Cross-Sectional Direct Assessment of Self-esteem Stability

Science.gov (United States)

Altmann, Tobias; Roth, Marcus

2018-01-01

Self-esteem stability describes fluctuations in the level of self-esteem experienced by individuals over a brief period of time. In recent decades, self-esteem stability has repeatedly been shown to be an important variable affecting psychological functioning. However, measures of self-esteem stability are few and lacking in validity. In this paper, we present the Self-Esteem Stability Scale (SESS), a unidimensional and very brief scale to directly assess self-esteem stability. In four studies (total N = 826), we describe the development of the SESS and present evidence for its validity with respect to individual outcomes (life satisfaction, neuroticism, and vulnerable narcissism) and dyadic outcomes (relationship satisfaction in self- and partner ratings) through direct comparisons with existing measures. The new SESS proved to be a stronger predictor than the existing scales and had incremental validity over and above self-esteem level. The results also showed that all cross-sectional measures of self-esteem stability were only moderately associated with variability in self-esteem levels assessed longitudinally with multiple administrations of the Rosenberg Self-Esteem Scale. We discuss this validity issue, arguing that direct and indirect assessment approaches measure relevant, yet different aspects of self-esteem stability. PMID:29487551

Producing explicit UPSILON flavor in e/sup +/e/sup -/ annihilation at DORIS energies. [neutral currents, cross section, signature, 15 to 20 MeV

Energy Technology Data Exchange (ETDEWEB)

Genz, H [Karlsruhe Univ. (TH) (Germany, F.R.). Inst. fuer Theoretische Kernphysik; Gorn, M [Karlsruhe Univ. (TH) (Germany, F.R.)

1978-07-31

If the neutral currents changing the flavor implicit in the UPSILON(9.5) are not suppressed, vector mesons with explicit UPSILON flavor should be produced in e/sup +/e/sup -/ annihilation at up to two e/sup +/e/sup -/ energies between ..sqrt..s approximately 5 - 6.5 GeV with a cross section sigma (peak, averaged over 7 MeV beam resolution) approximately 0.25% of sigma(e/sup +/e/sup -/..--> mu../sup +/..mu../sup -/). The signature would be monochromatic ..gamma.. lines with Esub(..gamma..)approximately 50-150 MeV, probably together with K production. Explicit flavor of a (anti QQ)sub(V) at 30 GeV would be produced at ..sqrt..s approximately 15-16 and ..sqrt..s approximately 20 GeV with sigmasup(averaged)sub(peak) approximately 3% and 5% of sigmasub(..mu../sup +/..mu../sup -/) with GAMMAsub(beam) = 27 and 48 MeV, respectively. The signature would be the same as above.

Study of the helium cross-section of unsymmetric disulfide self-assembled monolayers on Au(111)

Energy Technology Data Exchange (ETDEWEB)

Albayrak, Erol [Department of Materials and Metallurgical Engineering, Ahi Evran University, Kırşehir 40000 (Turkey); Karabuga, Semistan [Department of Chemistry, Kahramanmaraş Sütçü İmam University, Kahramanmaraş 46030 (Turkey); Bracco, Gianangelo [CNR-IMEM and Department of Physics, University of Genoa, Via Dodecaneso 33, Genoa 16146 (Italy); Danışman, M. Fatih, E-mail: danisman@metu.edu.tr [Department of Chemistry, Middle East Technical University, Ankara 06800 (Turkey)

2016-12-30

Highlights: • Unsymmetrtic disulfide (HDD and HOD) self assembled monolayers were grown on Au(111) by supersonic molecular beam deposition. • Helium scattering cross sections for these two different unsymmetric disulfides were determined. • A common low temperature film phase was observed for the studied disulfides. - Abstract: We have investigated the formation of self-assembled monolayers (SAMs) of 11-hydroxyundecyl decyl disulfide (CH{sub 3}-(CH{sub 2}){sub 9}-S-S-(CH{sub 2}){sub 11}-OH, HDD) and 11-hydroxyundecyl octadecyl disulfide (CH{sub 3}-(CH{sub 2}){sub 17}-S-S-(CH{sub 2}){sub 11}-OH, HOD) produced by supersonic molecular beam deposition (SMBD). The study has been carried out by means of helium diffraction at very low film coverage. In this regime helium single molecule cross sections have been estimated in a temperature range between 100 K and 450 K. The results show a different behavior above 300 K that has been interpreted as the starting of mobility with the formation of two thiolate moieties either linked by a gold adatom or distant enough to prevent cross section overlapping. Finally, helium diffraction patterns measured at 80 K for the SAMs grown at 200 K are discussed and the results support the proposed hypothesis of molecular dissociation based on the cross section data.

MXS cross-section preprocessor user's manual

International Nuclear Information System (INIS)

Parker, F.; Ishikawa, M.; Luck, L.

1987-03-01

The MXS preprocessor has been designed to reduce the execution time of programs using isotopic cross-section data and to both reduce the execution time and improve the accuracy of shielding-factor interpolation in the SIMMER-II accident analysis program. MXS is a dual-purpose preprocessing code to: (1) mix isotopes into materials and (2) fit analytic functions to the shelf-shielding data. The program uses the isotope microscopic neutron cross-section data from the CCCC standard interface file ISOTXS and the isotope Bondarenko self-shielding data from the CCCC standard interface file BRKOXS to generate cross-section and self-shielding data for materials. The materials may be a mixture of several isotopes. The self-shielding data for the materials may be the actual shielding factors or a set of coefficients for functions representing the background dependence of the shielding factors. A set of additional data is given to describe the functions necessary to interpolate the shielding factors over temperature

Radiative corrections to neutralino annihilation. Recent developments

International Nuclear Information System (INIS)

Herrmann, Bjoern

2010-11-01

Evaluating the relic density of dark matter is an interesting possibility to constrain the parameter space of new physics models. However, this calculation is affected by several sources of uncertainty. On the particle physics side, considerable progress has been made in the recent years concerning the calculation of the annihilation cross-section of dark matter, which is needed in this context. In particular, within the Minimal Supersymmetric Standard Model, the theoretical uncertainty has been reduced through the calculation of loop corrections. The present contribution gives an overview over the achievements that have been made in QCD corrections to neutralino pair annihilation. The numerical impact is illustrated for a few examples. (orig.)

e+e- annihilation into hadrons at SPEAR

International Nuclear Information System (INIS)

Feldman, G.J.

1975-08-01

The review of e + e - annihilation includes the detectors, total hadronic cross sections, charged multiplicity, and inclusive distributions. The new particles are excluded. Some results on the search for new particles, searches for monochromatic photons from the psi 1 , a search for nonleptonic decays of charmed mesons, and evidence for anomalous lepton production are also given. 20 references

The Self-esteem Stability Scale (SESS for Cross-Sectional Direct Assessment of Self-esteem Stability

Directory of Open Access Journals (Sweden)

Tobias Altmann

2018-02-01

Full Text Available Self-esteem stability describes fluctuations in the level of self-esteem experienced by individuals over a brief period of time. In recent decades, self-esteem stability has repeatedly been shown to be an important variable affecting psychological functioning. However, measures of self-esteem stability are few and lacking in validity. In this paper, we present the Self-Esteem Stability Scale (SESS, a unidimensional and very brief scale to directly assess self-esteem stability. In four studies (total N = 826, we describe the development of the SESS and present evidence for its validity with respect to individual outcomes (life satisfaction, neuroticism, and vulnerable narcissism and dyadic outcomes (relationship satisfaction in self- and partner ratings through direct comparisons with existing measures. The new SESS proved to be a stronger predictor than the existing scales and had incremental validity over and above self-esteem level. The results also showed that all cross-sectional measures of self-esteem stability were only moderately associated with variability in self-esteem levels assessed longitudinally with multiple administrations of the Rosenberg Self-Esteem Scale. We discuss this validity issue, arguing that direct and indirect assessment approaches measure relevant, yet different aspects of self-esteem stability.

A subtraction scheme for computing QCD jet cross sections at NNLO: regularization of doubly-real emissions

International Nuclear Information System (INIS)

Somogyi, Gabor; Trocsanyi, Zoltan; Del Duca, Vittorio

2007-01-01

We present a generalization of the dipole subtraction scheme for computing jet cross sections in electron-positron annihilation at next-to-next-to-leading order accuracy in perturbative QCD. In this first part we deal with the regularization of the doubly-real contribution to the NNLO correction

A subtraction scheme for computing QCD jet cross sections at NNLO: regularization of doubly-real emissions

Energy Technology Data Exchange (ETDEWEB)

Somogyi, Gabor [University of Debrecen and Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen, PO Box 51 (Hungary); Trocsanyi, Zoltan [University of Debrecen and Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen, PO Box 51 (Hungary); Del Duca, Vittorio [Istituto Nazionale di Fisica Nucleare, Sez. di Torino, via P. Giuria, 1 - 10125 Turin (Italy)

2007-01-15

We present a generalization of the dipole subtraction scheme for computing jet cross sections in electron-positron annihilation at next-to-next-to-leading order accuracy in perturbative QCD. In this first part we deal with the regularization of the doubly-real contribution to the NNLO correction.

A subtraction scheme for computing QCD jet cross sections at NNLO: regularization of real-virtual emission

Energy Technology Data Exchange (ETDEWEB)

Somogyi, Gabor; Trocsanyi, Zoltan [University of Debrecen and Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen, PO Box 51 (Hungary)

2007-01-15

We present a generalization of the dipole subtraction scheme for computing jet cross sections in electron-positron annihilation at next-to-next-to-leading order accuracy in perturbative QCD. In this second part we deal with the regularization of the real-virtual contribution to the NNLO correction.

Strange particle production in anti pp annihilation from 1.22 to 1.35 GeV/c

International Nuclear Information System (INIS)

Handler, T.; Plano, R.J.; Brucker, E.B.; Koller, E.L.; Taylor, S.; Stamer, P.E.

1976-01-01

Experimental results on antiproton-proton annihilations at 5 incident momenta in the range 1.22-1.35 GeV/c into final states with at least one visible K 1 0 meson are presented. Based on a total of 5855 events, cross sections and resonance fractions for all experimentally accessible final states are determined. The total cross section for annihilation into strange particles with at least one visible K 1 0 is 2069 +- 45 μb. Copious resonance production is observed but there is no significant evidence for the formation of a resonance in the s-channel. (Auth.)

Radiative corrections to the hadronic cross-section measurement at DA{phi}NE

Energy Technology Data Exchange (ETDEWEB)

Khoze, V.A. [Durham Univ. of Durham, Durham (United Kingdom). Dept. of Physics; Konchatnij, M.I.; Merenkov, NP.; Shekhovzova, O.N. [National Science Centre Kharkov Institute of Physics and Technology, Karkhov (Ukraine); Pancheri, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Frascati, RM (Italy); Trentadue, L. [Parma Univ., Parma (Italy). Dipt. di Fisica

2000-07-01

The hadronic invariant mass distribution for the process of electron--positron annihilation into a pair of charged pions accompanied by a photon radiated from the initial state has been studied for the region of DA{phi}NE energies. The Born cross-section and the electromagnetic radiative corrections to it are calculated for realistic conditions of the KLOE detector. The dependence on the physical parameters which define the event selection is obtained.

Source theory analysis of electron--positron annihilation experiments

International Nuclear Information System (INIS)

Schwinger, J.

1975-01-01

The phenomenological viewpoint already applied to deep inelastic scattering is extended to the discussion of electron-positron annihilation experiments. Some heuristic arguments lead to simple forms for the pion differential cross section that are in reasonable accord with the published experimental data in the energy interval 3 to 4.8 GeV

Electron-positron annihilation: unitarity, scaling and electrodynamics at high energies

Energy Technology Data Exchange (ETDEWEB)

Karl, G [Guelph Univ., Ontario (Canada); European Organization for Nuclear Research, Geneva (Switzerland))

1974-01-01

The work on e/sup +/e/sup -/ annihilation by Cabibbo, Wolfenstein and the author is reviewed. The restrictions of unitarity are analyzed and the connection between the cross sections sigmasub(h) (into hadrons) and sigmasub(..mu..) (into muons) is derived. The possibility of non-scaling in e/sup +/e/sup -/ annihilation is studied and it is pointed out that it leads to no contradiction with presently available information. It is further pointed out that non-scaling could provide a cut-off mechanism for quantum electrodynamics.

Does self-efficacy mediate the cross-sectional relationship between perceived quality of health care and self-management of diabetes? : Results from Diabetes MILES - Australia

NARCIS (Netherlands)

Tregea, Hannah; Lee, Christina; Browne, Jessica L.; Pouwer, F.; Speight, Jane

2016-01-01

Objective: Quality of health care (QoC) and self-efficacy may affect self-management of diabetes, but such effects are not well understood. We examined the indirect role of diabetes-specific self-efficacy (DSE) and generalised self-efficacy (GSE) in mediating the cross-sectional relationship between

The electroweak interaction in e+e- annihilations

International Nuclear Information System (INIS)

Marshall, R.

1982-04-01

The role of e + e - annihilation in studying the weak neutral current, at PETRA and PEP, is reviewed. The way in which the vector and axial vector couplings appear in the total cross sections, the angular distributions and the polarisation dependences are discussed. The dependence of external gauge models on the results of PETRA and PEP experiments is examined. (U.K.)

Multi-messenger constraints and pressure from dark matter annihilation into e--e+ pairs

International Nuclear Information System (INIS)

Wechakama, Maneenate

2013-01-01

Despite striking evidence for the existence of dark matter from astrophysical observations, dark matter has still escaped any direct or indirect detection until today. Therefore a proof for its existence and the revelation of its nature belongs to one of the most intriguing challenges of nowadays cosmology and particle physics. The present work tries to investigate the nature of dark matter through indirect signatures from dark matter annihilation into electron-positron pairs in two different ways, pressure from dark matter annihilation and multi-messenger constraints on the dark matter annihilation cross-section. We focus on dark matter annihilation into electron-positron pairs and adopt a model-independent approach, where all the electrons and positrons are injected with the same initial energy E 0 ∝m dm c 2 . The propagation of these particles is determined by solving the diffusion-loss equation, considering inverse Compton scattering, synchrotron radiation, Coulomb collisions, bremsstrahlung, and ionization. The first part of this work, focusing on pressure from dark matter annihilation, demonstrates that dark matter annihilation into electron-positron pairs may affect the observed rotation curve by a significant amount. The injection rate of this calculation is constrained by INTEGRAL, Fermi, and H.E.S.S. data. The pressure of the relativistic electron-positron gas is computed from the energy spectrum predicted by the diffusion-loss equation. For values of the gas density and magnetic field that are representative of the Milky Way, it is estimated that the pressure gradients are strong enough to balance gravity in the central parts if E 0 0 . By comparing the predicted rotation curves with observations of dwarf and low surface brightness galaxies, we show that the pressure from dark matter annihilation may improve the agreement between theory and observations in some cases, but it also imposes severe constraints on the model parameters (most notably, the

Gamma and pizero production in e+e- annihilation

International Nuclear Information System (INIS)

Fong, A.

1980-01-01

Inclusive cross sections of γ's and π 0 mesons in hadronic events produced by electron-positron annihilation for the center-of-mass energy range 4.9 to 7.4 GeV are presented. Scale invariance of the inclusive spectra is exhibited in this energy range, and their normalization and shape are seen to be consistent with those of spectra arising from the decay of the π 0 . The fraction of center-of-mass energy carried away by the γ's at high energies is found to be = 0.24 +- 0.01. The π 0 inclusive cross section is seen to be consistent in normalization and shape with half the charged-π cross section between x = 0.15 and 0.75, with an integrated inclusive cross-section ratio of sigma(π 0 )/[sigma(π + ) + sigma(π - )] = 0.48 +- 0.05. 60 figures, 7 tables

Measurements of Positronium Formation Cross Sections for Positron-Kr, Xe Scattering

Science.gov (United States)

Kauppila, W. E.; Kwan, C. K.; Li, H.; Stein, T. S.; Zhou, S.

1997-04-01

Our experimental approach(S. Zhou et al., Phys. Rev. Lett. 73, 236 (1994).) for measuring Ps formation cross sections (Q_Ps) involves passing a variable energy positron beam through a gas scattering cell and detecting the 511 keV annihilation gamma rays resulting from the decay of para-Ps and from the interaction of ortho-Ps with the walls of the scattering cell. It is found that the Q_Ps curves for both Kr and Xe rise rapidly from their formation threshold energies of 7.2 and 5.3 eV, reach maxima within about 10 eV of their thresholds and then decrease to become rather small (less than 10% of the peak heights) above 100 eV. At the maxima Q_Ps accounts for more than 50% of the total scattering cross sections. There is some evidence of possible small scale structure in the Q_Ps curves between 10 and 100 eV. The present results are consistent with the prior measurements of Diana et al.( L.M. Diana et al., in "Atomic Physics with Positrons", edited by J.W. Humberston and E.A.G. Armour (Plenum, New York and London, 1987), p. 55; and in "Positron Annihilation", edited by L. Dorikens-Vanpraet et al. (World Scientific, Singapore, 1989), p. 311.) from near threshold to 70 eV for Kr and from 15 to 100 eV for Xe.

Zadig: latest improvements to Bremsstrahlung treatment and in-flight annihilation scheme; Zadig: amelioration du traitement Bremsstrahlung et traitement de l'annihilation en vol

Energy Technology Data Exchange (ETDEWEB)

Menard, St

2006-07-01

Multigroup cross-section for the 3-dimensional Monte-Carlo transport code DIANE are produced by the ZADIG code. Although DIANE does not transport the electrons and positrons, the production of Bremsstrahlung photons induced by the electrons and positrons during their slowing down is taken into account in the ZADIG code because the electron-gamma cascade is an important process in high energy gamma ray transport. ZADIG does not distinguish positrons from electrons except for the positron annihilation. However, the user can turn on this direction. This report presents the latest improvements to the Bremsstrahlung model of ZADIG and to the positron annihilation algorithm implemented in the code. Positrons can annihilate either in flight or at rest in the latest release of ZADIG. As MCNP does not take into account the annihilation in flight, results of ZADIG-DIANE calculations are compared to the results of GEANT-4 in order to validate the annihilation scheme of ZADIG. The results with annihilation divided by the results without present similar trends between 0.6 and 10 MeV for the 2 codes (GEANT-4 and ZADIG-DIANE), in other words an influence of 5%, so the annihilation scheme programmed in ZADIG appears to be satisfying and can be considered as validated.

Can annihilating dark matter be lighter than a few GeVs?

International Nuclear Information System (INIS)

Boehm, C; Ensslin, T A; Silk, J

2004-01-01

We estimate the gamma-ray fluxes from the residual annihilations of dark matter (DM) particles having a mass m dm from [MeV, O(10) GeV] (a possible solution to the DM issue provided they have a new kind of interactions and no significant coupling to the Z) and compare them to observations. We find that particles lighter than O(100 MeV) can be viable DM candidates provided their dominant annihilation cross section is S-wave suppressed so as to satisfy the gamma-ray constraints. A similar conclusion is obtained for particles lighter than O(10) GeV from the study of radio fluxes, assuming a NFW profile and that they mainly annihilate into electrons

Danish emergency nurses' attitudes towards self-harm - a cross-sectional study

DEFF Research Database (Denmark)

Perbøll, Penille Wimmer; Hammer, N. M.; Østergaard, Birte

2015-01-01

AIM: The aim of this study was to examine Danish emergency nurses' attitudes toward people hospitalized after an acetaminophen poisoning. Furthermore, the study examined the relationship between attitudes and factors such as age, gender, and education on self-harm. METHODS: A cross-sectional design...... was applied. Nurses from seven emergency departments (EDs) in a region in Denmark were asked to complete the Danish version of Attitudes towards Deliberate Self-Harm Questionnaire (ADSHQ). RESULTS: Of the 254 eligible nurses working in the ED, 122 returned the questionnaires, leaving the response rate at 48......%. Results show that the emergency nurses generally held positive attitudes toward patients with acetaminophen poisoning. Nurses with longer ED experience held more positive attitudes, and women scored significantly higher than men on the whole scale. Only 19% of the respondents had received education...

Isotropic extragalactic flux from dark matter annihilations: lessons from interacting dark matter scenarios

Energy Technology Data Exchange (ETDEWEB)

Moliné, Ángeles [CFTP, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Schewtschenko, Jascha A.; Boehm, Céline [Institute for Particle Physics Phenomenology (IPPP), Durham University, Durham DH1 3LE (United Kingdom); Palomares-Ruiz, Sergio [Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, E-46071 Valencia (Spain); Baugh, Carlton M., E-mail: maria.moline@ist.utl.pt, E-mail: jascha@schewtschenko.net, E-mail: Sergio.Palomares.Ruiz@ific.uv.es, E-mail: c.m.boehm@durham.ac.uk, E-mail: c.m.baugh@durham.ac.uk [Institute for Computational Cosmology (ICC), Durham University, Durham DH1 3LE (United Kingdom)

2016-08-01

The extragalactic γ-ray and neutrino emission may have a contribution from dark matter (DM) annihilations. In the case of discrepancies between observations and standard predictions, one could infer the DM pair annihilation cross section into cosmic rays by studying the shape of the energy spectrum. So far all analyses of the extragalactic DM signal have assumed the standard cosmological model (ΛCDM) as the underlying theory. However, there are alternative DM scenarios where the number of low-mass objects is significantly suppressed. Therefore the characteristics of the γ-ray and neutrino emission in these models may differ from ΛCDM as a result. Here we show that the extragalactic isotropic signal in these alternative models has a similar energy dependence to that in ΛCDM, but the overall normalisation is reduced. The similarities between the energy spectra combined with the flux suppression could lead one to misinterpret possible evidence for models beyond ΛCDM as being due to CDM particles annihilating with a much weaker cross section than expected.

Isotropic extragalactic flux from dark matter annihilations: lessons from interacting dark matter scenarios

International Nuclear Information System (INIS)

Moliné, Ángeles; Schewtschenko, Jascha A.; Boehm, Céline; Palomares-Ruiz, Sergio; Baugh, Carlton M.

2016-01-01

The extragalactic γ-ray and neutrino emission may have a contribution from dark matter (DM) annihilations. In the case of discrepancies between observations and standard predictions, one could infer the DM pair annihilation cross section into cosmic rays by studying the shape of the energy spectrum. So far all analyses of the extragalactic DM signal have assumed the standard cosmological model (ΛCDM) as the underlying theory. However, there are alternative DM scenarios where the number of low-mass objects is significantly suppressed. Therefore the characteristics of the γ-ray and neutrino emission in these models may differ from ΛCDM as a result. Here we show that the extragalactic isotropic signal in these alternative models has a similar energy dependence to that in ΛCDM, but the overall normalisation is reduced. The similarities between the energy spectra combined with the flux suppression could lead one to misinterpret possible evidence for models beyond ΛCDM as being due to CDM particles annihilating with a much weaker cross section than expected.

SUSY-QCD corrections to the (co)annihilation of neutralino dark matter within the MSSM

Energy Technology Data Exchange (ETDEWEB)

Meinecke, Moritz

2015-06-15

Based on experimental observations, it is nowadays assumed that a large component of the matter content in the universe is comprised of so-called cold dark matter. Furthermore, latest measurements of the temperature fluctuations of the cosmic microwave background provided an estimation of the dark matter relic density at a measurement error of one percent (concerning the experimental 1σ-error). The lightest neutralino χ 0{sub 1}, a particle which subsumes under the phenomenologically interesting category of weakly interacting massive particles, is a viable dark matter candidate for many supersymmetric (SUSY) models whose relic density Ω{sub χ} {sub 0{sub 1}} happens to lie quite naturally within the experimentally favored ballpark of dark matter. The high experimental precision can be used to constrain the SUSY parameter space to its cosmologically favored regions and to pin down phenomenologically interesting scenarios. However, to actually benefit from this progress on the experimental side it is also mandatory to minimize the theoretical uncertainties. An important quantity within the calculation of the neutralino relic density is the thermally averaged sum over different annihilation and coannihilation cross sections of the neutralino and further supersymmetric particles. It is now assumed and also partly proven that these cross sections can be subject to large loop corrections which can even shift the associated Ω{sub χ} {sub 0{sub 1}} by a factor larger than the current experimental error. However, most of these corrections are yet unknown. In this thesis, we calculate higher-order corrections for some of the most important (co)annihilation channels both within the framework of the R-parity conserving Minimal Supersymmetric Standard Model (MSSM) and investigate their impact on the final neutralino relic density Ω{sub χ} {sub 0{sub 1}}. More precisely, this work provides the full O(α{sub s}) corrections of supersymmetric quantum chromodynamics (SUSY

Validity of Hansen-Roach cross sections in low-enriched uranium systems

International Nuclear Information System (INIS)

Busch, R.D.; O'Dell, R.D.

1991-01-01

Within the nuclear criticality safety community, the Hansen-Roach 16 group cross section set has been the ''standard'' for use in k eff calculations over the past 30 years. Yet even with its widespread acceptance, there are still questions about its validity and adequacy, about the proper procedure for calculating the potential scattering cross section, σ p , for uranium and plutonium, and about the concept of resonance self shielding and its impact on cross sections. This paper attempts to address these questions. It provides a brief background on the Hansen-Roach cross sections. Next is presented a review of resonances in cross sections, self shielding of these resonances, and the use of σ p to characterize resonance self shielding. Three prescriptions for calculating σ p are given. Finally, results of several calculations of k eff on low-enriched uranium systems are provided to confirm the validity of the Hansen-Roach cross sections when applied to such systems

Validity of Hansen-Roach cross sections in low-enriched uranium systems

International Nuclear Information System (INIS)

Busch, R.D.; O'Dell, R.D.

1991-01-01

Within the nuclear criticality safety community, the Hansen-Roach 16 group cross section set has been the standard for use in k eff calculations over the past 30 years. Yet even with its widespread acceptance, there are still questions about its validity and adequacy, about the proper procedure for calculating the potential scattering cross section, σ p , for uranium and plutonium, and about the concept of resonance self shielding and its impact on cross sections. This paper attempts to address these questions. It provides a brief background on the Hansen-Roach cross sections. Next is presented a review of resonances in cross sections, self shielding of these resonances, and the use of σ p to characterize resonance self shielding. Three prescriptions for calculating σ p are given. Finally, results of several calculations of k eff on low-enriched uranium systems are provided to confirm the validity of the Hansen-Roach cross sections when applied to such systems. (Author)

Revisiting Bremsstrahlung emission associated with Light Dark Matter annihilations

CERN Document Server

Böhm, C

2006-01-01

We compute the single bremsstrahlung emission associated with the pair annihilation of spin-0 particles into electrons and positrons, via the t-channel exchange of a heavy fermion. We compare our result with the work of Beacom et al. . Unlike what is stated in the literature, we show that the Bremsstrahlung cross section is not necessarily given by the tree-level annihilation cross section (for a generalized kinematics) times a factor related to the emission of a soft photon. Such a factorization appears only in the soft photon limit or in the approximation where the masses of the particles in the initial and final states are negligible with respect to the mass of the internal particle. However, in the latter case, we do not recover the same factor as for e^+ e- --> mu^+ mu^- gamma. Numerically the difference, in the hard photon limit, is as large as a factor 3.6. However the effect on the upper limit of the dark matter mass is not significant. Using gamma ray observations, we obtain an upper limit on the dar...

Probing dark matter decay and annihilation with Fermi LAT observations of nearby galaxy clusters

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiaoyuan [Chinese Academy of Sciences, Beijing (China). National Astronomical Observatories; Max-Planck-Institut fuer Physik, Muenchen (Germany); Vertongen, Gilles [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Institut d' Astrophysique de Paris, 75 - Paris (France); Weniger, Christoph [Max-Planck-Institut fuer Physik, Muenchen (Germany)

2011-09-15

Galaxy clusters are promising targets for indirect dark matter searches. Gamma-ray signatures from the decay or annihilation of dark matter particles inside these clusters could be observable with the Fermi Large Area Telescope (LAT). Based on three years of Fermi LAT gamma-ray data, we analyze the flux coming from eight nearby clusters individually as well as in a combined likelihood analysis. Concentrating mostly on signals from dark matter decay, we take into account uncertainties of the cluster masses as determined by X-ray observations and model the cluster emission with extended sources. We do not find significant emission from any of the considered clusters and present limits on the dark matter lifetime and annihilation cross-section. We compare our lifetime limits derived from cluster observations with the limits that can be obtained from the extragalactic gamma-ray background, and find that in case of hadronic decay the cluster limits become competitive at dark matter masses below a few hundred GeV. Finally, we show that in presence of dark matter substructures down to 10{sup -6} solar masses the limits on the dark matter annihilation cross-section could improve by a factor of a few hundred, possibly going down to the thermal cross-section of 3 x 10{sup -26} cm{sup 3}s{sup -1} for dark matter masses annihilation into b anti b. As a direct application of our results, we derive limits on the lifetime of gravitino dark matter in scenarios with R-parity violation. Implications of these limits for the possible observation of long-lived superparticles at the LHC are discussed. (orig.)

Probing dark matter decay and annihilation with Fermi LAT observations of nearby galaxy clusters

International Nuclear Information System (INIS)

Huang, Xiaoyuan; Vertongen, Gilles; Weniger, Christoph

2011-09-01

Galaxy clusters are promising targets for indirect dark matter searches. Gamma-ray signatures from the decay or annihilation of dark matter particles inside these clusters could be observable with the Fermi Large Area Telescope (LAT). Based on three years of Fermi LAT gamma-ray data, we analyze the flux coming from eight nearby clusters individually as well as in a combined likelihood analysis. Concentrating mostly on signals from dark matter decay, we take into account uncertainties of the cluster masses as determined by X-ray observations and model the cluster emission with extended sources. We do not find significant emission from any of the considered clusters and present limits on the dark matter lifetime and annihilation cross-section. We compare our lifetime limits derived from cluster observations with the limits that can be obtained from the extragalactic gamma-ray background, and find that in case of hadronic decay the cluster limits become competitive at dark matter masses below a few hundred GeV. Finally, we show that in presence of dark matter substructures down to 10 -6 solar masses the limits on the dark matter annihilation cross-section could improve by a factor of a few hundred, possibly going down to the thermal cross-section of 3 x 10 -26 cm 3 s -1 for dark matter masses < or similar 150 GeV and annihilation into b anti b. As a direct application of our results, we derive limits on the lifetime of gravitino dark matter in scenarios with R-parity violation. Implications of these limits for the possible observation of long-lived superparticles at the LHC are discussed. (orig.)

Antiproton-proton annihilations into four prongs at 7.2 GeV/c

International Nuclear Information System (INIS)

Leeuw, A. de.

1979-01-01

Annihilation reactions are described in which four charged pions and also maybe uncharged particles are produced. Data was acquired in an antiproton-proton experiment at a beam momentum of 7.2 GeV/c and 220K pictures of the CERN 2m HBC were measured. Cross sections have been determined and angular distributions of the pions and of some resonances are given. Two models that describe annihilation reactions are treated, the so called CLA model and a simple quark model. (C.F./Auth.)

Neutralino-nucleon cross sections for detection of low-mass dark matter particles

International Nuclear Information System (INIS)

Titkova, I.V.; Bednyakov, V.A.

2004-01-01

The weakly interacting massive particle (WIMP) is one of the main candidates for the relic dark matter. In the effective low-energy minimal supersymmetric standard model (effMSSM), the neutralino-nucleon spin and scalar cross sections in the low-mass regime were calculated. The calculated cross sections are compared with almost all currently available experimental exclusion curves for spin-dependent WIMP-proton and WIMP-neutron cross sections. It is demonstrated that in general about two-orders-of-magnitude improvement of the current DM experimental sensitivities is needed to reach the effMSSM SUSY predictions. To avoid misleading discrepancies between data and SUSY calculations, it is preferable to use a mixed spin-scalar coupling approach. It is noticed that the DAMA evidence favours the light Higgs coupling approach. It is noticed that the DAMA evidence favours the light Higgs sector in the effMSSM, a high event rate in a 73 Ge detector and relatively high upgoing muon fluxes from relic neutralino annihilations on the Earth and the Sun

Obese Chinese Primary-School Students and Low Self-Esteem: A Cross-Sectional Study

OpenAIRE

Xue-Yan, Zhang; Dong-Mei, Li; Dan-Dan, Xu; Le-Shan, Zhou

2016-01-01

Objectives The aim of this study was to examine several factors related to low self-esteem among obese Chinese primary-school students. Methods A cross-sectional study was conducted between June 2009 and June 2010. A total of 1,410 primary-school students (China grades 4 - 6) in Changsha city were divided into normal weight (n = 1,084), overweight (n = 211), and obese groups (n = 115) according to world health organization (WHO) g...

Does self-efficacy mediate the cross-sectional relationship between perceived quality of health care and self-management of diabetes?

DEFF Research Database (Denmark)

Tregea, Hannah; Lee, Christina; Browne, Jessica L

2016-01-01

between self-reported QoC and diabetes self-management. DESIGN: Diabetes MILES-Australia was a national survey of 3,338 adults with diabetes. We analysed data from 1,624 respondents (age: M = 52.1, SD = 13.9) with type 1 (T1D; n = 680) or type 2 diabetes (T2D; n = 944), who responded to a version...... of the survey containing key measures. MAIN OUTCOME MEASURES: self-reported healthy eating, physical activity, self-monitoring of blood glucose frequency, HbA1c, medication/insulin adherence. RESULTS: We used Preacher and Hayes' bootstrapping method, controlling for age, gender and diabetes duration, to test......OBJECTIVE: Quality of health care (QoC) and self-efficacy may affect self-management of diabetes, but such effects are not well understood. We examined the indirect role of diabetes-specific self-efficacy (DSE) and generalised self-efficacy (GSE) in mediating the cross-sectional relationship...

Gamma-ray Background Spectrum and Annihilation Rate in the Baryon-symmetric Big-bang Cosmology

Science.gov (United States)

Puget, J. L.

1973-01-01

An attempt was made to acquire experimental information on the problem of baryon symmetry on a large cosmological scale by observing the annihilation products. Data cover absorption cross sections and background radiation due to other sources for the two main products of annihilation, gamma rays and neutrinos. Test results show that the best direct experimental test for the presence of large scale antimatter lies in the gamma ray background spectrum between 1 and 70 MeV.

Positron annihilation imaging device using multiple offset rings of detectors

International Nuclear Information System (INIS)

Thompson, C.J.

1981-01-01

This patent application relates to a positron annihilation imaging device comprising two or more coaxial circular arrays of detectors (2,2'), with the detectors in one array angularly offset with respect to the detectors in the adjacent array to detect more than one tomographic image simultaneously through different cross-sections of a patient. (author)

The Distribution and Annihilation of Dark Matter Around Black Holes

Science.gov (United States)

Schnittman, Jeremy D.

2015-01-01

We use a Monte Carlo code to calculate the geodesic orbits of test particles around Kerr black holes, generating a distribution function of both bound and unbound populations of dark matter (DM) particles. From this distribution function, we calculate annihilation rates and observable gamma-ray spectra for a few simple DM models. The features of these spectra are sensitive to the black hole spin, observer inclination, and detailed properties of the DM annihilation cross-section and density profile. Confirming earlier analytic work, we find that for rapidly spinning black holes, the collisional Penrose process can reach efficiencies exceeding 600%, leading to a high-energy tail in the annihilation spectrum. The high particle density and large proper volume of the region immediately surrounding the horizon ensures that the observed flux from these extreme events is non-negligible.

Search for γ -Ray Line Signals from Dark Matter Annihilations in the Inner Galactic Halo from 10 Years of Observations with H.E.S.S.

Science.gov (United States)

Abdallah, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Angüner, E. O.; Arakawa, M.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bonnefoy, S.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Capasso, M.; Caroff, S.; Carosi, A.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Colafrancesco, S.; Condon, B.; Conrad, J.; Davids, I. D.; Decock, J.; Deil, C.; Devin, J.; deWilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O'C.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Emery, G.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Garrigoux, T.; Gaté, F.; Giavitto, G.; Giebels, B.; Glawion, D.; Glicenstein, J. F.; Gottschall, D.; Grondin, M.-H.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holch, T. L.; Holler, M.; Horns, D.; Ivascenko, A.; Iwasaki, H.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katsuragawa, M.; Katz, U.; Kerszberg, D.; Khangulyan, D.; Khélifi, B.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Liu, R.; Lohse, T.; Lorentz, M.; López-Coto, R.; Lypova, I.; Malyshev, D.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morâ, K.; Moulin, E.; Murach, T.; Nakashima, S.; de Naurois, M.; Ndiyavala, H.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poireau, V.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Rauth, R.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Rinchiuso, L.; Romoli, C.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Saito, S.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schandri, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seglar-Arroyo, M.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Shiningayamwe, K.; Simoni, R.; Sol, H.; Spanier, F.; Spir-Jacob, M.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Steppa, C.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tsirou, M.; Tsuji, N.; Tuffs, R.; Uchiyama, Y.; van der Walt, J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Zorn, J.; Żywucka, N.; H. E. S. S. Collaboration

2018-05-01

Spectral lines are among the most powerful signatures for dark matter (DM) annihilation searches in very-high-energy γ rays. The central region of the Milky Way halo is one of the most promising targets given its large amount of DM and proximity to Earth. We report on a search for a monoenergetic spectral line from self-annihilations of DM particles in the energy range from 300 GeV to 70 TeV using a two-dimensional maximum likelihood method taking advantage of both the spectral and spatial features of the signal versus background. The analysis makes use of Galactic center observations accumulated over ten years (2004-2014) with the H.E.S.S. array of ground-based Cherenkov telescopes. No significant γ -ray excess above the background is found. We derive upper limits on the annihilation cross section ⟨σ v ⟩ for monoenergetic DM lines at the level of 4 ×10-28 cm3 s-1 at 1 TeV, assuming an Einasto DM profile for the Milky Way halo. For a DM mass of 1 TeV, they improve over the previous ones by a factor of 6. The present constraints are the strongest obtained so far for DM particles in the mass range 300 GeV-70 TeV. Ground-based γ -ray observations have reached sufficient sensitivity to explore relevant velocity-averaged cross sections for DM annihilation into two γ -ray photons at the level expected from the thermal relic density for TeV DM particles.

The Isotropic Radio Background and Annihilating Dark Matter

Energy Technology Data Exchange (ETDEWEB)

Hooper, Dan [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Belikov, Alexander V. [Institut d' Astrophysique (France); Jeltema, Tesla E. [Univ. of California, Santa Cruz, CA (United States); Linden, Tim [Univ. of California, Santa Cruz, CA (United States); Profumo, Stefano [Univ. of California, Santa Cruz, CA (United States); Slatyer, Tracy R. [Princeton Univ., Princeton, NJ (United States)

2012-11-01

Observations by ARCADE-2 and other telescopes sensitive to low frequency radiation have revealed the presence of an isotropic radio background with a hard spectral index. The intensity of this observed background is found to exceed the flux predicted from astrophysical sources by a factor of approximately 5-6. In this article, we consider the possibility that annihilating dark matter particles provide the primary contribution to the observed isotropic radio background through the emission of synchrotron radiation from electron and positron annihilation products. For reasonable estimates of the magnetic fields present in clusters and galaxies, we find that dark matter could potentially account for the observed radio excess, but only if it annihilates mostly to electrons and/or muons, and only if it possesses a mass in the range of approximately 5-50 GeV. For such models, the annihilation cross section required to normalize the synchrotron signal to the observed excess is sigma v ~ (0.4-30) x 10^-26 cm^3/s, similar to the value predicted for a simple thermal relic (sigma v ~ 3 x 10^-26 cm^3/s). We find that in any scenario in which dark matter annihilations are responsible for the observed excess radio emission, a significant fraction of the isotropic gamma ray background observed by Fermi must result from dark matter as well.

Photoneutron cross sections for {sup 59}Co. Systematic uncertainties of data from various experiments

Energy Technology Data Exchange (ETDEWEB)

Varlamov, V.V. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Davydov, A.I. [Lomonosov Moscow State University, Physics Faculty, Moscow (Russian Federation); Ishkhanov, B.S. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Lomonosov Moscow State University, Physics Faculty, Moscow (Russian Federation)

2017-09-15

Data on partial photoneutron reaction cross sections (γ, 1n), (γ, 2n), and (γ, 3n) for {sup 59}Co obtained in two experiments carried out at Livermore (USA) were analyzed. The sources of radiation in both experiments were the monoenergetic photon beams from the annihilation in flight of relativistic positrons. The total yield was sorted by the neutron multiplicity, taking into account the difference in the neutron energy spectra for different multiplicity. The two quoted studies differ in the method of determining the neutron. Significant systematic disagreements between the results of the two experiments exist. They are considered to be caused by large systematic uncertainties in partial cross sections, since they do not satisfy physical criteria for reliability of the data. To obtain reliable cross sections of partial and total photoneutron reactions a new method combining experimental data and theoretical evaluation was used. It is based on the experimental neutron yield cross section which is rather independent of neutron multiplicity and the transitional neutron multiplicity functions of the combined photonucleon reaction model (CPNRM). The model transitional multiplicity functions were used for the decomposition of the neutron yield cross section into the contributions of partial reactions. The results of the new evaluation noticeably differ from the partial cross sections obtained in the two experimental studies are under discussion. (orig.)

Lambda production in electron-positron annihilation at 29 GeV

International Nuclear Information System (INIS)

Baden, A.R.

1986-01-01

The inclusive cross-section for the production of the singly-strange baryons Lambda and anti Lambda, along with the differential cross-sections in momentum and energy, are measured by e + e - annihilation at a center-of-mass energy of 29 GeV. The charged decay mode Lambda → pπ is used in a search for polarization. Such a polarization may be used as a check of CP invariance in Lambda production. The sample of events with two detected decays is analyzed for correlations in production angle. All results are summarized in the conclusion of this thesis

Search for dark matter annihilation in the Galactic Center with IceCube-79

International Nuclear Information System (INIS)

Aartsen, M.G.; Hill, G.C.; Robertson, S.; Whelan, B.J.; Abraham, K.; Bernhard, A.; Coenders, S.; Gross, A.; Holzapfel, K.; Huber, M.; Jurkovic, M.; Krings, K.; Resconi, E.; Veenkamp, J.; Ackermann, M.; Berghaus, P.; Bernardini, E.; Bretz, H.P.; Cruz Silva, A.H.; Gluesenkamp, T.; Gora, D.; Jacobi, E.; Kaminsky, B.; Karg, T.; Middell, E.; Mohrmann, L.; Nahnhauer, R.; Schoenwald, A.; Shanidze, R.; Spiering, C.; Stasik, A.; Stoessl, A.; Strotjohann, N.L.; Terliuk, A.; Usner, M.; Yanez, J.P.; Adams, J.; Brown, A.M.; Aguilar, J.A.; Heereman, D.; Meagher, K.; Meures, T.; O'Murchadha, A.; Pinat, E.; Ahlers, M.; Arguelles, C.; Beiser, E.; BenZvi, S.; Braun, J.; Chirkin, D.; Day, M.; Desiati, P.; Diaz-Velez, J.C.; Fadiran, O.; Fahey, S.; Feintzeig, J.; Ghorbani, K.; Gladstone, L.; Halzen, F.; Hanson, K.; Hoshina, K.; Jero, K.; Karle, A.; Kelley, J.L.; Kheirandish, A.; McNally, F.; Merino, G.; Middlemas, E.; Morse, R.; Richter, S.; Sabbatini, L.; Tobin, M.N.; Tosi, D.; Vandenbroucke, J.; Van Santen, J.; Wandkowsky, N.; Weaver, C.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wille, L.; Ahrens, M.; Bohm, C.; Dumm, J.P.; Finley, C.; Flis, S.; Hulth, P.O.; Hultqvist, K.; Walck, C.; Wolf, M.; Zoll, M.; Altmann, D.; Classen, L.; Kappes, A.; Tselengidou, M.; Anderson, T.; Arlen, T.C.; Dunkman, M.; Eagan, R.; Groh, J.C.; Huang, F.; Keivani, A.; Lanfranchi, J.L.; Quinnan, M.; Smith, M.W.E.; Stanisha, N.A.; Tesic, G.; Archinger, M.; Baum, V.; Boeser, S.; Eberhardt, B.; Ehrhardt, T.; Koepke, L.; Kroll, G.; Luenemann, J.; Sander, H.G.; Schatto, K.; Wiebe, K.; Auffenberg, J.; Bissok, M.; Blumenthal, J.; Glagla, M.; Gier, D.; Gretskov, P.; Haack, C.; Hansmann, B.; Hellwig, D.; Kemp, J.; Konietz, R.; Koob, A.; Leuermann, M.; Leuner, J.; Paul, L.; Puetz, J.; Raedel, L.; Reimann, R.; Rongen, M.; Schimp, M.; Schoenen, S.; Schukraft, A.; Stahlberg, M.; Vehring, M.; Wallraff, M.; Wichary, C.; Wiebusch, C.H.; Bai, X.; Barwick, S.W.; Yodh, G.; Bay, R.; Filimonov, K.; Price, P.B.; Woschnagg, K.; Beatty, J.J.; Becker Tjus, J.; Bos, F.; Eichmann, B.; Fedynitch, A.; Kroll, M.; Saba, S.M.; Schoeneberg, S.; Becker, K.H.; Bindig, D.; Fischer-Wasels, T.; Helbing, K.; Hickford, S.; Hoffmann, R.; Klaes, J.; Kopper, S.; Naumann, U.; Obertacke, A.; Omairat, A.; Posselt, J.; Soldin, D.; Berley, D.; Blaufuss, E.; Cheung, E.; Christy, B.; Felde, J.; Hellauer, R.; Hoffman, K.D.; Huelsnitz, W.; Maunu, R.; Olivas, A.; Redl, P.; Schmidt, T.; Sullivan, G.W.; Wissing, H.; Besson, D.Z.; Binder, G.; Gerhardt, L.; Ha, C.; Klein, S.R.; Miarecki, S.; Boersma, D.J.; Botner, O.; Euler, S.; Hallgren, A.

2015-01-01

The Milky Way is expected to be embedded in a halo of dark matter particles, with the highest density in the central region, and decreasing density with the halo-centric radius. Dark matter might be indirectly detectable at Earth through a flux of stable particles generated in dark matter annihilations and peaked in the direction of the Galactic Center. We present a search for an excess flux of muon (anti-) neutrinos from dark matter annihilation in the Galactic Center using the cubic-kilometer-sized IceCube neutrino detector at the South Pole. There, the Galactic Center is always seen above the horizon. Thus, new and dedicated veto techniques against atmospheric muons are required to make the southern hemisphere accessible for IceCube. We used 319.7 live-days of data from IceCube operating in its 79-string configuration during 2010 and 2011. No neutrino excess was found and the final result is compatible with the background. We present upper limits on the self-annihilation cross-section, left angle σ A right angle, for WIMP masses ranging from 30 GeV up to 10 TeV, assuming cuspy (NFW) and flat-cored (Burkert) dark matter halo profiles, reaching down to ≅ 4 . 10 -24 cm 3 s -1 , and ≅ 2.6 . 10 -23 cm 3 s -1 for the νanti ν channel, respectively. (orig.)

Probing dark matter annihilation in the Galaxy with antiprotons and gamma rays

Energy Technology Data Exchange (ETDEWEB)

Cuoco, Alessandro; Heisig, Jan; Korsmeier, Michael; Krämer, Michael, E-mail: cuoco@physik.rwth-aachen.de, E-mail: heisig@physik.rwth-aachen.de, E-mail: korsmeier@physik.rwth-aachen.de, E-mail: mkraemer@physik.rwth-aachen.de [Institute for Theoretical Particle Physics and Cosmology, RWTH Aachen University, 52056 Aachen (Germany)

2017-10-01

A possible hint of dark matter annihilation has been found in Cuoco, Korsmeier and Krämer (2017) from an analysis of recent cosmic-ray antiproton data from AMS-02 and taking into account cosmic-ray propagation uncertainties by fitting at the same time dark matter and propagation parameters. Here, we extend this analysis to a wider class of annihilation channels. We find consistent hints of a dark matter signal with an annihilation cross-section close to the thermal value and with masses in range between 40 and 130 GeV depending on the annihilation channel. Furthermore, we investigate in how far the possible signal is compatible with the Galactic center gamma-ray excess and recent observation of dwarf satellite galaxies by performing a joint global fit including uncertainties in the dark matter density profile. As an example, we interpret our results in the framework of the Higgs portal model.

All-flavour Search for Neutrinos from Dark Matter Annihilations in the Milky Way with IceCube/DeepCore

CERN Document Server

INSPIRE-00266703

2016-01-01

We present the first IceCube search for a signal of dark matter annihilations in the Milky Way using all-flavour neutrino-induced particle cascades. The analysis focuses on the DeepCore sub-detector of IceCube, and uses the surrounding IceCube strings as a veto region in order to select starting events in the DeepCore volume. We use 329 live-days of data from IceCube operating in its 86-string configuration during 2011-2012. No neutrino excess is found, the final result being compatible with the background-only hypothesis. From this null result, we derive upper limits on the velocity-averaged self-annihilation cross-section, , for dark matter candidate masses ranging from 30 GeV up to 10 TeV, assuming both a cuspy and a flat-cored dark matter halo profile. For dark matter masses between 200 GeV and 10 TeV, the results improve on all previous IceCube results on , reaching a level of 10^{-23} cm^3 s^-1, depending on the annihilation channel assumed, for a cusped NFW profile. The analysis demonstrates that all-f...

Problem of summing up ladder diagrams in quantum electrodynamics. [Cross sections

Energy Technology Data Exchange (ETDEWEB)

Gadzhiev, S A; Livashvili, A I [Azerbajdzhanskij Gosudarstvennyj Univ., Baku (USSR)

1975-03-01

A class of ladder diagrams in an asymptotic mode is considered, and a series of the perturbation theory for the given class of diagrams reduces to an integral equation obtained without approximations whatsoever. As applications of the method proposed, two electrodynamic processes are considered: the two-photon annihilation of an e/sup +/e/sup -/-pair and scattering of electons in Coulomb field. Matrix elements are provided. To derive the equations, Dirac equations and commutation relations are used. A conclusion is drawn that for the process, the log-log asymptotics and polar approximation lead to the fact that as the energy grows the cross-section of the process drops and the solution obtained indicates that such a drop occurs up to an energy of 10/sup 5/ GeV. For the second process, the region of large pulses transmitted by an electron to the external field does not lead to an increase in amplitude and cross-section.

Asymmetric dark matter: residual annihilations and self-interactions arXiv

CERN Document Server

Baldes, Iason; Panci, Paolo; Petraki, Kalliopi; Sala, Filippo; Taoso, Marco

Dark matter (DM) coupled to light mediators has been invoked to resolve the putative discrepancies between collisionless cold DM and galactic structure observations. However, $\\gamma$-ray searches and the CMB strongly constrain such scenarios. To ease the tension, we consider asymmetric DM. We show that, contrary to the common lore, detectable annihilations occur even for large asymmetries, and derive bounds from the CMB, $\\gamma$-ray, neutrino and antiproton searches. We then identify the viable space for self-interacting DM. Direct detection does not exclude this scenario, but provides a way to test it.

Dark matter annihilations into two light fermions and one gauge boson. General analysis and antiproton constraints

International Nuclear Information System (INIS)

Garny, Mathias; Ibarra, Alejandro; Vogl, Stefan

2011-12-01

We study in this paper the scenario where the dark matter is constituted by Majo- rana particles which couple to a light Standard Model fermion and an extra scalar via a Yukawa coupling. In this scenario, the annihilation rate into the light fermions with the mediation of the scalar particle is strongly suppressed by the mass of the fermion. Nevertheless, the helicity suppression is lifted by the associated emission of a gauge boson, yielding annihilation rates which could be large enough to allow the indirect detection of the dark matter particles. We perform a general analysis of this scenario, calculating the annihilation cross section of the processes χχ → f anti fV when the dark matter particle is a SU(2) L singlet or doublet, f is a lepton or a quark, and V is a photon, a weak gauge boson or a gluon. We point out that the annihilation rate is particularly enhanced when the dark matter particle is degenerate in mass to the intermediate scalar particle, which is a scenario barely constrained by collider searches of exotic charged or colored particles. Lastly, we derive upper limits on the relevant cross sections from the non-observation of an excess in the cosmic antiproton-to-proton ratio measured by PAMELA. (orig.)

Dark matter annihilations into two light fermions and one gauge boson. General analysis and antiproton constraints

Energy Technology Data Exchange (ETDEWEB)

Garny, Mathias [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro; Vogl, Stefan [Technische Univ. Muenchen, Garching (Germany). Physik-Department

2011-12-15

We study in this paper the scenario where the dark matter is constituted by Majo- rana particles which couple to a light Standard Model fermion and an extra scalar via a Yukawa coupling. In this scenario, the annihilation rate into the light fermions with the mediation of the scalar particle is strongly suppressed by the mass of the fermion. Nevertheless, the helicity suppression is lifted by the associated emission of a gauge boson, yielding annihilation rates which could be large enough to allow the indirect detection of the dark matter particles. We perform a general analysis of this scenario, calculating the annihilation cross section of the processes {chi}{chi} {yields} f anti fV when the dark matter particle is a SU(2){sub L} singlet or doublet, f is a lepton or a quark, and V is a photon, a weak gauge boson or a gluon. We point out that the annihilation rate is particularly enhanced when the dark matter particle is degenerate in mass to the intermediate scalar particle, which is a scenario barely constrained by collider searches of exotic charged or colored particles. Lastly, we derive upper limits on the relevant cross sections from the non-observation of an excess in the cosmic antiproton-to-proton ratio measured by PAMELA. (orig.)

Implementation of the rapid cross section adjustment approach at General Electric

International Nuclear Information System (INIS)

Cowan, C.L.; Kujawski, E.; Protsik, R.

1978-01-01

The General Electric rapid cross section adjustment approach was developed to use the shielding factor method for formulating multigroup cross sections. In this approach, space- and composition-dependent cross sections for a particular reactor or shield design are prepared from a generalized cross section library by the use of resonance self-shielding factors, and by the adjustment of elastic scattering cross sections for the local neutron flux spectra. The principal tool in the cross section adjustment package is the data processing code TDOWN. This code was specified to give the user a high degree of flexibility in the analysis of advanced reactor designs. Of particular interest in the analysis of critical experiments is the ability to carry out cell heterogeneity self-shielding calculations using a multiregion equivalence relationship, and the homogenization of the cross sections over the specified cell with the flux weighting obtained from transport theory calculations. Extensive testing of the rapid cross section adjustment approach, including comparisons with Monte Carlo methods, indicated that this approach can be utilized with a high degree of confidence in the design analysis of complex fast reactor systems. 2 figures, 1 table

Annihilation vs. Decay: Constraining dark matter properties from a gamma-ray detection

CERN Document Server

Palomares-Ruiz, Sergio

2010-01-01

Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is also the possibility of unstable (but long-lived) dark matter, produced thermally or otherwise. We propose a strategy to distinguish between dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way dwarf spheroidal galaxies with current or future gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both. In addition, once the type of signal is established, we show how these measurements could help to extract information about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay channels, and the p...

Search for Dark Matter Annihilation in Galaxy Groups.

Science.gov (United States)

Lisanti, Mariangela; Mishra-Sharma, Siddharth; Rodd, Nicholas L; Safdi, Benjamin R

2018-03-09

We use 413 weeks of publicly available Fermi Pass 8 gamma-ray data combined with recently developed galaxy group catalogs to search for evidence of dark matter annihilation in extragalactic halos. In our study, we use luminosity-based mass estimates and mass-to-concentration relations to infer the J factors and associated uncertainties for hundreds of galaxy groups within a redshift range z≲0.03. We employ a conservative substructure boost factor model, which only enhances the sensitivity by an O(1) factor. No significant evidence for dark matter annihilation is found, and we exclude thermal relic cross sections for dark matter masses below ∼30  GeV to 95% confidence in the bb[over ¯] annihilation channel. These bounds are comparable to those from Milky Way dwarf spheroidal satellite galaxies. The results of our analysis increase the tension but do not rule out the dark matter interpretation of the Galactic Center excess. We provide a catalog of the galaxy groups used in this study and their inferred properties, which can be broadly applied to searches for extragalactic dark matter.

Search for Dark Matter Annihilation in Galaxy Groups

Science.gov (United States)

Lisanti, Mariangela; Mishra-Sharma, Siddharth; Rodd, Nicholas L.; Safdi, Benjamin R.

2018-03-01

We use 413 weeks of publicly available Fermi Pass 8 gamma-ray data combined with recently developed galaxy group catalogs to search for evidence of dark matter annihilation in extragalactic halos. In our study, we use luminosity-based mass estimates and mass-to-concentration relations to infer the J factors and associated uncertainties for hundreds of galaxy groups within a redshift range z ≲0.03 . We employ a conservative substructure boost factor model, which only enhances the sensitivity by an O (1 ) factor. No significant evidence for dark matter annihilation is found, and we exclude thermal relic cross sections for dark matter masses below ˜30 GeV to 95% confidence in the b b ¯ annihilation channel. These bounds are comparable to those from Milky Way dwarf spheroidal satellite galaxies. The results of our analysis increase the tension but do not rule out the dark matter interpretation of the Galactic Center excess. We provide a catalog of the galaxy groups used in this study and their inferred properties, which can be broadly applied to searches for extragalactic dark matter.

Comparison of muon-pair production to the quark-antiquark annihilation model

International Nuclear Information System (INIS)

Hogan, G.E.; Anderson, K.J.; Coleman, R.N.; Karhi, K.P.; McDonald, K.T.; Newman, C.B.; Pilcher, J.E.; Rosenberg, E.I.; Sanders, G.H.; Smith, A.J.S.; Thaler, J.J.

1979-01-01

New data on muon-pair production at 225 GeV/c by π - , π + , and proton beams are analyzed with regard to the production mechanism. The observed spin alignment of the pair and the dependence of the cross section on beam-particle type are strong indications that the production is through electromagnetic quark-antiquark annihilation

A statistical method to estimate low-energy hadronic cross sections

Science.gov (United States)

Balassa, Gábor; Kovács, Péter; Wolf, György

2018-02-01

In this article we propose a model based on the Statistical Bootstrap approach to estimate the cross sections of different hadronic reactions up to a few GeV in c.m.s. energy. The method is based on the idea, when two particles collide a so-called fireball is formed, which after a short time period decays statistically into a specific final state. To calculate the probabilities we use a phase space description extended with quark combinatorial factors and the possibility of more than one fireball formation. In a few simple cases the probability of a specific final state can be calculated analytically, where we show that the model is able to reproduce the ratios of the considered cross sections. We also show that the model is able to describe proton-antiproton annihilation at rest. In the latter case we used a numerical method to calculate the more complicated final state probabilities. Additionally, we examined the formation of strange and charmed mesons as well, where we used existing data to fit the relevant model parameters.

12C(n , 2 n )11C cross section from threshold to 26.5 MeV

Science.gov (United States)

Yuly, M.; Eckert, T.; Hartshaw, G.; Padalino, S. J.; Polsin, D. N.; Russ, M.; Simone, A. T.; Brune, C. R.; Massey, T. N.; Parker, C. E.; Fitzgerald, R.; Sangster, T. C.; Regan, S. P.

2018-02-01

The 12C(n ,2 n )11C cross section was measured from just below threshold to 26.5 MeV using the Pelletron accelerator at Ohio University. Monoenergetic neutrons, produced via the 3H(d ,n )4He reaction, were allowed to strike targets of polyethylene and graphite. Activation of both targets was measured by counting positron annihilations resulting from the β+ decay of 11C. Annihilation gamma rays were detected, both in coincidence and singly, using back-to-back NaI detectors. The incident neutron flux was determined indirectly via 1H(n ,p ) protons elastically scattered from the polyethylene target. Previous measurements fall into upper and lower bands; the results of the present measurement are consistent with the upper band.

A systematic effective operator analysis of semi-annihilating dark matter

International Nuclear Information System (INIS)

Cai, Yi; Spray, Andrew

2017-01-01

Semi-annihilation is a generic feature of dark matter theories stabilized by symmetries larger than a ℤ 2 . It contributes to thermal freeze out, but is irrelevant for direct and collider searches. This allows semi-annihilating dark matter to avoid those limits in a natural way. We use an effective operator approach to make the first model-independent study of the associated phenomenology. We enumerate all possible operators that contribute to 2→2 semi-annihilation up to dimension 6, plus leading terms at dimension 7. We find that when the only light states charged under the dark symmetry are dark matter, the model space is highly constrained. Only fifteen operators exist, and just two for single-component dark sectors. If there can be additional light, unstable “dark partner” states the possible phenomenology greatly increases, at the cost of additional model dependence in the dark partner decay modes. We also derive the irreducible constraints on models with single-component dark matter from cosmic ray searches and astrophysical observations. We find that for semi-annihilation to electrons and light quarks, the thermal relic cross sections can be excluded for dark matter masses up to 100 GeV. However, significant model space for semi-annihilating dark matter remains.

THE EFFECTS OF DARK MATTER ANNIHILATION ON COSMIC REIONIZATION

Energy Technology Data Exchange (ETDEWEB)

Kaurov, Alexander A.; Hooper, Dan; Gnedin, Nickolay Y., E-mail: kaurov@uchicago.edu [Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 (United States)

2016-12-20

We revisit the possibility of constraining the properties of dark matter (DM) by studying the epoch of cosmic reionization. Previous studies have shown that DM annihilation was unlikely to have provided a large fraction of the photons which ionized the universe, but instead played a subdominant role relative to stars and quasars. The DM might, however, have begun to efficiently annihilate with the formation of primordial microhalos at z  ∼ 100–200, much earlier than the formation of the first stars. Therefore, if DM annihilation ionized the universe at even the percent level over the interval z  ∼ 20–100, it could leave a significant imprint on the global optical depth, τ . Moreover, we show that cosmic microwave background polarization data and future 21 cm measurements will enable us to more directly probe the DM contribution to the optical depth. In order to compute the annihilation rate throughout the epoch of reionization, we adopt the latest results from structure formation studies and explore the impact of various free parameters on our results. We show that future measurements could make it possible to place constraints on the DM’s annihilation cross-sections, which are at a level comparable to those obtained from the observations of dwarf galaxies, cosmic-ray measurements, and studies of recombination.

Unresolved resonance range cross section, probability tables and self shielding factor

International Nuclear Information System (INIS)

Sublet, J.Ch.; Blomquist, R.N.; Goluoglu, S.; Mac Farlane, R.E.

2009-07-01

The performance and methodology of 4 processing codes have been compared in the unresolved resonance range of a selected set of isotopes. Those isotopes have been chosen to encompass most cases encountered in the unresolved energy range contained in major libraries like Endf/B-7 or Jeff-3.1.1. The code results comparison is accompanied by data format and formalism examinations and processing code fine-interpretation study. After some improvements, the results showed generally good agreement, although not perfect with infinite dilute cross-sections. However, much larger differences occur when shelf-shielded effective cross-sections are compared. The infinitely dilute cross-section are often plot checked but it is the probability table derived and shelf-shielded cross sections that are used and interpreted in criticality and transport calculations. This suggests that the current evaluation data format and formalism, in the unresolved resonance range should be tightened up, ambiguities removed. In addition production of the shelf shielded cross-sections should be converged to a much greater accuracy. (author)

Multiparticle production in antiproton-proton annihilation reactions at 7.23 GeV/c and 12 GeV/c

International Nuclear Information System (INIS)

Pijlgroms, B.J.

1982-01-01

This thesis describes some aspects of antiproton-proton experiments at 7.23 and 12 GeV/c in the CERN 2m HBC. Chapter 1 starts with some general information regarding the different experiments. The subsequent description of a simple monitoring system for the HPD, is followed by a discussion of two software facilities. The first chapter is concluded with a description of the search for the existence of the hypothetical I-meson, by which these routines were very useful. Chapter 2 begins with a detailed description of the correction procedures for the measurement- and scan-losses. This is followed by the determination of the charged and neutral topological cross sections and of the annihilation and non-annihilation cross sections for six- and more prongs, including channels with strange particles. A detailed study is made of the s-dependence of the annihilation cross sections. A short discussion is given of the models of Goldberg, Eylon and Harari, and Gotsmann and Nussinov. Chapter 3 deals with the search for physical event-by-event fluctuations in the hadronic temperature of the annihilation reactions. The first part of this chapter is devoted to a historical review of the statistical and semi-statistical models for high energy physics. The second part describes the actual analysis of the data. The fluctuations are measured in the central region y approximately 0 and in the complete sample. It is shown that the observation of an ideal thermal production is in contradiction with the observation of large fluctuations in the temperature. (Auth.)

Order α2sub(s) correction to jet cross sections in e+e- annihilation

International Nuclear Information System (INIS)

Fabricius, K.; Schmitt, I.; Schierholz, G.; Kramer, G.

1980-09-01

We calculate the Sterman-Weinberg type cross section for three jets and the 0(α 2 sub(s)) correction to the thrust distribution 1/sigma dsigma/dT. The effect on 1/sigma dsigma/dT is sizable (in the anti MS scheme) but not in conflict with the expected convergence of the perturbation series. (orig.)

Heating of galactic gas by dark matter annihilation in ultracompact minihalos

Energy Technology Data Exchange (ETDEWEB)

Clark, Hamish A.; Iwanus, Nikolas; Lewis, Geraint F. [Sydney Institute for Astronomy, School of Physics A28, The University of Sydney, NSW 2006 (Australia); Elahi, Pascal J. [International Centre for Radio Astronomy Research, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Scott, Pat, E-mail: hamish.clark@sydney.edu.au, E-mail: nikolas.iwanus@sydney.edu.au, E-mail: pascal.elahi@uwa.edu.au, E-mail: geraint.lewis@sydney.edu.au, E-mail: p.scott@imperial.ac.uk [Department of Physics, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom)

2017-05-01

The existence of substructure in halos of annihilating dark matter would be expected to substantially boost the rate at which annihilation occurs. Ultracompact minihalos of dark matter (UCMHs) are one of the more extreme examples of this. The boosted annihilation can inject significant amounts of energy into the gas of a galaxy over its lifetime. Here we determine the impact of the boost factor from UCMH substructure on the heating of galactic gas in a Milky Way-type galaxy, by means of N-body simulation. If 1% of the dark matter exists as UCMHs, the corresponding boost factor can be of order 10{sup 5}. For reasonable values of the relevant parameters (annihilation cross section 3×10{sup −26} cm{sup 3} s{sup −1}, dark matter mass 100 GeV, 10% heating efficiency), we show that the presence of UCMHs at the 0.1% level would inject enough energy to eject significant amounts of gas from the halo, potentially preventing star formation within ∼1 kpc of the halo centre.

Skyrmion creation and annihilation by spin waves

International Nuclear Information System (INIS)

Liu, Yizhou; Yin, Gen; Lake, Roger K.; Zang, Jiadong; Shi, Jing

2015-01-01

Single skyrmion creation and annihilation by spin waves in a crossbar geometry are theoretically analyzed. A critical spin-wave frequency is required both for the creation and the annihilation of a skyrmion. The minimum frequencies for creation and annihilation are similar, but the optimum frequency for creation is below the critical frequency for skyrmion annihilation. If a skyrmion already exists in the cross bar region, a spin wave below the critical frequency causes the skyrmion to circulate within the central region. A heat assisted creation process reduces the spin-wave frequency and amplitude required for creating a skyrmion. The effective field resulting from the Dzyaloshinskii-Moriya interaction and the emergent field of the skyrmion acting on the spin wave drive the creation and annihilation processes

On the Sunyaev-Zel'dovich effect from dark matter annihilation or decay in galaxy clusters

International Nuclear Information System (INIS)

Lavalle, Julien; Boehm, Céline; Barthès, Julien

2010-01-01

We revisit the prospects for detecting the Sunyaev Zel'dovich (SZ) effect induced by dark matter (DM) annihilation or decay. We show that with standard (or even extreme) assumptions for DM properties, the optical depth associated with relativistic electrons injected from DM annihilation or decay is much smaller than that associated with thermal electrons, when averaged over the angular resolution of current and future experiments. For example, we find: τ DM ∼ 10 −9 −10 −5 (depending on the assumptions) for m χ = 1 GeV and a density profile ρ∝r −1 for a template cluster located at 50 Mpc and observed within an angular resolution of 10'', compared to τ th ∼ 10 −3 −10 −2 . This, together with a full spectral analysis, enables us to demonstrate that, for a template cluster with generic properties, the SZ effect due to DM annihilation or decay is far below the sensitivity of the Planck satellite. This is at variance with previous claims regarding heavier annihilating DM particles. Should DM be made of lighter particles, the current constraints from 511 keV observations on the annihilation cross section or decay rate still prevent a detectable SZ effect. Finally, we show that spatial diffusion sets a core of a few kpc in the electron distribution, even for very cuspy DM profiles, such that improving the angular resolution of the instrument, eg with ALMA, does not necessarily improve the detection potential. We provide useful analytical formulæ parameterized in terms of the DM mass, decay rate or annihilation cross section and DM halo features, that allow quick estimates of the SZ effect induced by any given candidate and any DM halo profile

Detecting electron neutrinos from solar dark matter annihilation by JUNO

International Nuclear Information System (INIS)

Guo, Wan-Lei

2016-01-01

We explore the electron neutrino signals from light dark matter (DM) annihilation in the Sun for the large liquid scintillator detector JUNO. In terms of the spectrum features of three typical DM annihilation channels χχ → νν-bar , τ + τ − , b b-bar , we take two sets of selection conditions to calculate the expected signals and atmospheric neutrino backgrounds based on the Monte Carlo simulation data. Then the JUNO sensitivities to the spin independent DM-nucleon and spin dependent DM-proton cross sections are presented. It is found that the JUNO projected sensitivities are much better than the current spin dependent direct detection experimental limits for the νν-bar and τ + τ − channels. In the spin independent case, the JUNO will give the better sensitivity to the DM-nucleon cross section than the LUX and CDMSlite limits for the νν-bar channel with the DM mass lighter than 6.5 GeV . If the νν-bar or τ + τ − channel is dominant, the future JUNO results are very helpful for us to understand the tension between the DAMA annual modulation signal and other direct detection exclusions

Annihilation probability density and other applications of the Schwinger multichannel method to the positron and electron scattering

International Nuclear Information System (INIS)

Varella, Marcio Teixeira do Nascimento

2001-12-01

We have calculated annihilation probability densities (APD) for positron collisions against He atom and H 2 molecule. It was found that direct annihilation prevails at low energies, while annihilation following virtual positronium (Ps) formation is the dominant mechanism at higher energies. In room-temperature collisions (10 -2 eV) the APD spread over a considerable extension, being quite similar to the electronic densities of the targets. The capture of the positron in an electronic Feshbach resonance strongly enhanced the annihilation rate in e + -H 2 collisions. We also discuss strategies to improve the calculation of the annihilation parameter (Z eff ), after debugging the computational codes of the Schwinger Multichannel Method (SMC). Finally, we consider the inclusion of the Ps formation channel in the SMC and show that effective configurations (pseudo eigenstates of the Hamiltonian of the collision ) are able to significantly reduce the computational effort in positron scattering calculations. Cross sections for electron scattering by polyatomic molecules were obtained in three different approximations: static-exchange (SE); tatic-exchange-plus-polarization (SEP); and multichannel coupling. The calculations for polar targets were improved through the rotational resolution of scattering amplitudes in which the SMC was combined with the first Born approximation (FBA). In general, elastic cross sections (SE and SEP approximations) showed good agreement with available experimental data for several targets. Multichannel calculations for e - -H 2 O scattering, on the other hand, presented spurious structures at the electronic excitation thresholds (author)

MPI version of NJOY and its application to multigroup cross-section generation

Energy Technology Data Exchange (ETDEWEB)

Alpan, A.; Haghighat, A.

1999-07-01

Multigroup cross-section libraries are needed in performing neutronics calculations. These libraries are referred to as broad-group libraries. The number of energy groups and group structure are highly dependent on the application and/or user's objectives. For example, for shielding calculations, broad-group libraries such as SAILOR and BUGLE with 47-neutron and 20-gamma energy groups are used. The common procedure to obtain a broad-group library is a three-step process: (1) processing pointwise ENDF (PENDF) format cross sections; (2) generating fine-group cross sections; and (3) collapsing fine-group cross sections to broad-group. The NJOY code is used to prepare fine-group cross sections by processing pointwise ENDF data. The code has several modules, each one performing a specific task. For instance, the module RECONR performs linearization and reconstruction of the cross sections, and the module GROUPR generates multigroup self-shielded cross sections. After fine-group, i.e., groupwise ENDF (GENDF), cross sections are produced, cross sections are self-shielded, and a one-dimensional transport calculation is performed to obtain flux spectra at specific regions in the model. These fluxes are then used as weighting functions to collapse the fine-group cross sections to obtain a broad-group cross-section library. The third step described is commonly performed by the AMPX code system. SMILER converts NJOY GENDF filed to AMPX master libraries, AJAX collects the master libraries. BONAMI performs self-shielding calculations, NITAWL converts the AMPX master library to a working library, XSDRNPM performs one-dimensional transport calculations, and MALOCS collapses fine-group cross sections to broad-group. Finally, ALPO is used to generate ANISN format libraries. In this three-step procedure, generally NJOY requires the largest amount of CPU time. This time varies depending on the user's specified parameters for each module, such as reconstruction tolerances

MPI version of NJOY and its application to multigroup cross-section generation

International Nuclear Information System (INIS)

Alpan, A.; Haghighat, A.

1999-01-01

Multigroup cross-section libraries are needed in performing neutronics calculations. These libraries are referred to as broad-group libraries. The number of energy groups and group structure are highly dependent on the application and/or user's objectives. For example, for shielding calculations, broad-group libraries such as SAILOR and BUGLE with 47-neutron and 20-gamma energy groups are used. The common procedure to obtain a broad-group library is a three-step process: (1) processing pointwise ENDF (PENDF) format cross sections; (2) generating fine-group cross sections; and (3) collapsing fine-group cross sections to broad-group. The NJOY code is used to prepare fine-group cross sections by processing pointwise ENDF data. The code has several modules, each one performing a specific task. For instance, the module RECONR performs linearization and reconstruction of the cross sections, and the module GROUPR generates multigroup self-shielded cross sections. After fine-group, i.e., groupwise ENDF (GENDF), cross sections are produced, cross sections are self-shielded, and a one-dimensional transport calculation is performed to obtain flux spectra at specific regions in the model. These fluxes are then used as weighting functions to collapse the fine-group cross sections to obtain a broad-group cross-section library. The third step described is commonly performed by the AMPX code system. SMILER converts NJOY GENDF filed to AMPX master libraries, AJAX collects the master libraries. BONAMI performs self-shielding calculations, NITAWL converts the AMPX master library to a working library, XSDRNPM performs one-dimensional transport calculations, and MALOCS collapses fine-group cross sections to broad-group. Finally, ALPO is used to generate ANISN format libraries. In this three-step procedure, generally NJOY requires the largest amount of CPU time. This time varies depending on the user's specified parameters for each module, such as reconstruction tolerances, temperatures

Search for dark matter annihilation in the Galactic Center with IceCube-79

Energy Technology Data Exchange (ETDEWEB)

Aartsen, M.G.; Hill, G.C.; Robertson, S.; Whelan, B.J. [University of Adelaide, School of Chemistry and Physics, Adelaide, SA (Australia); Abraham, K.; Bernhard, A.; Coenders, S.; Gross, A.; Holzapfel, K.; Huber, M.; Jurkovic, M.; Krings, K.; Resconi, E.; Veenkamp, J. [Technische Universitaet Muenchen, Garching (Germany); Ackermann, M.; Berghaus, P.; Bernardini, E.; Bretz, H.P.; Cruz Silva, A.H.; Gluesenkamp, T.; Gora, D.; Jacobi, E.; Kaminsky, B.; Karg, T.; Middell, E.; Mohrmann, L.; Nahnhauer, R.; Schoenwald, A.; Shanidze, R.; Spiering, C.; Stasik, A.; Stoessl, A.; Strotjohann, N.L.; Terliuk, A.; Usner, M.; Yanez, J.P. [DESY, Zeuthen (Germany); Adams, J.; Brown, A.M. [University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch (New Zealand); Aguilar, J.A.; Heereman, D.; Meagher, K.; Meures, T.; O' Murchadha, A.; Pinat, E. [Universite Libre de Bruxelles, Science Faculty CP230, Brussels (Belgium); Ahlers, M.; Arguelles, C.; Beiser, E.; BenZvi, S.; Braun, J.; Chirkin, D.; Day, M.; Desiati, P.; Diaz-Velez, J.C.; Fadiran, O.; Fahey, S.; Feintzeig, J.; Ghorbani, K.; Gladstone, L.; Halzen, F.; Hanson, K.; Hoshina, K.; Jero, K.; Karle, A.; Kelley, J.L.; Kheirandish, A.; McNally, F.; Merino, G.; Middlemas, E.; Morse, R.; Richter, S.; Sabbatini, L.; Tobin, M.N.; Tosi, D.; Vandenbroucke, J.; Van Santen, J.; Wandkowsky, N.; Weaver, C.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wille, L. [Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Department of Physics, Madison, WI (United States); Ahrens, M.; Bohm, C.; Dumm, J.P.; Finley, C.; Flis, S.; Hulth, P.O.; Hultqvist, K.; Walck, C.; Wolf, M.; Zoll, M. [Oskar Klein Centre, Stockholm University, Department of Physics, Stockholm (Sweden); Altmann, D.; Classen, L.; Kappes, A.; Tselengidou, M. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Anderson, T.; Arlen, T.C.; Dunkman, M.; Eagan, R.; Groh, J.C.; Huang, F.; Keivani, A.; Lanfranchi, J.L.; Quinnan, M.; Smith, M.W.E.; Stanisha, N.A.; Tesic, G. [Pennsylvania State University, Department of Physics, University Park, PA (United States); Archinger, M.; Baum, V.; Boeser, S.; Eberhardt, B.; Ehrhardt, T.; Koepke, L.; Kroll, G.; Luenemann, J.; Sander, H.G.; Schatto, K.; Wiebe, K. [University of Mainz, Institute of Physics, Mainz (Germany); Auffenberg, J.; Bissok, M.; Blumenthal, J.; Glagla, M.; Gier, D.; Gretskov, P.; Haack, C.; Hansmann, B.; Hellwig, D.; Kemp, J.; Konietz, R.; Koob, A.; Leuermann, M.; Leuner, J.; Paul, L.; Puetz, J.; Raedel, L.; Reimann, R.; Rongen, M.; Schimp, M.; Schoenen, S.; Schukraft, A.; Stahlberg, M.; Vehring, M.; Wallraff, M.; Wichary, C.; Wiebusch, C.H. [RWTH Aachen University, III. Physikalisches Institut, Aachen (Germany); Bai, X. [South Dakota School of Mines and Technology, Physics Department, Rapid City, SD (United States); Barwick, S.W.; Yodh, G. [University of California, Department of Physics and Astronomy, Irvine, CA (United States); Bay, R.; Filimonov, K.; Price, P.B.; Woschnagg, K. [University of California, Department of Physics, Berkeley, CA (United States); Beatty, J.J. [Ohio State University, Department of Physics and Center for Cosmology and Astro-Particle Physics, Columbus, OH (United States); Ohio State University, Department of Astronomy, Columbus, OH (United States); Becker Tjus, J.; Bos, F.; Eichmann, B.; Fedynitch, A.; Kroll, M.; Saba, S.M.; Schoeneberg, S. [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Bochum (Germany); Becker, K.H.; Bindig, D.; Fischer-Wasels, T.; Helbing, K.; Hickford, S.; Hoffmann, R.; Klaes, J.; Kopper, S.; Naumann, U.; Obertacke, A.; Omairat, A.; Posselt, J.; Soldin, D. [University of Wuppertal, Department of Physics, Wuppertal (Germany); Berley, D.; Blaufuss, E.; Cheung, E.; Christy, B.; Felde, J.; Hellauer, R.; Hoffman, K.D.; Huelsnitz, W.; Maunu, R.; Olivas, A.; Redl, P.; Schmidt, T.; Sullivan, G.W.; Wissing, H. [University of Maryland, Department of Physics, College Park, MD (United States); Besson, D.Z. [University of Kansas, Department of Physics and Astronomy, Lawrence, KS (United States); Binder, G.; Gerhardt, L.; Ha, C.; Klein, S.R.; Miarecki, S. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Boersma, D.J.; Botner, O.; Euler, S.; Hallgren, A.; Collaboration: IceCube Collaboration; and others

2015-10-15

The Milky Way is expected to be embedded in a halo of dark matter particles, with the highest density in the central region, and decreasing density with the halo-centric radius. Dark matter might be indirectly detectable at Earth through a flux of stable particles generated in dark matter annihilations and peaked in the direction of the Galactic Center. We present a search for an excess flux of muon (anti-) neutrinos from dark matter annihilation in the Galactic Center using the cubic-kilometer-sized IceCube neutrino detector at the South Pole. There, the Galactic Center is always seen above the horizon. Thus, new and dedicated veto techniques against atmospheric muons are required to make the southern hemisphere accessible for IceCube. We used 319.7 live-days of data from IceCube operating in its 79-string configuration during 2010 and 2011. No neutrino excess was found and the final result is compatible with the background. We present upper limits on the self-annihilation cross-section, left angle σ{sub A} right angle, for WIMP masses ranging from 30 GeV up to 10 TeV, assuming cuspy (NFW) and flat-cored (Burkert) dark matter halo profiles, reaching down to ≅ 4 . 10{sup -24} cm{sup 3}s{sup -1}, and ≅ 2.6 . 10{sup -23} cm{sup 3}s{sup -1} for the νanti ν channel, respectively. (orig.)

Testing a self-determination theory model of children's physical activity motivation: a cross-sectional study.

Science.gov (United States)

Sebire, Simon J; Jago, Russell; Fox, Kenneth R; Edwards, Mark J; Thompson, Janice L

2013-09-26

Understanding children's physical activity motivation, its antecedents and associations with behavior is important and can be advanced by using self-determination theory. However, research among youth is largely restricted to adolescents and studies of motivation within certain contexts (e.g., physical education). There are no measures of self-determination theory constructs (physical activity motivation or psychological need satisfaction) for use among children and no previous studies have tested a self-determination theory-based model of children's physical activity motivation. The purpose of this study was to test the reliability and validity of scores derived from scales adapted to measure self-determination theory constructs among children and test a motivational model predicting accelerometer-derived physical activity. Cross-sectional data from 462 children aged 7 to 11 years from 20 primary schools in Bristol, UK were analysed. Confirmatory factor analysis was used to examine the construct validity of adapted behavioral regulation and psychological need satisfaction scales. Structural equation modelling was used to test cross-sectional associations between psychological need satisfaction, motivation types and physical activity assessed by accelerometer. The construct validity and reliability of the motivation and psychological need satisfaction measures were supported. Structural equation modelling provided evidence for a motivational model in which psychological need satisfaction was positively associated with intrinsic and identified motivation types and intrinsic motivation was positively associated with children's minutes in moderate-to-vigorous physical activity. The study provides evidence for the psychometric properties of measures of motivation aligned with self-determination theory among children. Children's motivation that is based on enjoyment and inherent satisfaction of physical activity is associated with their objectively-assessed physical

The 12C(n, 2n)11C cross section from threshold to 26.5 MeV.

Science.gov (United States)

Yuly, M; Eckert, T; Hartshaw, G; Padalino, S J; Polsin, D N; Russ, M; Simone, A T; Brune, C R; Massey, T N; Parker, C E; Fitzgerald, R; Sangster, T C; Regan, S P

2018-02-01

The 12 C(n, 2n) 11 C cross section was measured from just below threshold to 26.5 MeV using the Pelletron accelerator at Ohio University. Monoenergetic neutrons, produced via the 3 H(d,n) 4 He reaction, were allowed to strike targets of polyethylene and graphite. Activation of both targets was measured by counting positron annihilations resulting from the β + decay of 11 C. Annihilation gamma rays were detected, both in coincidence and singly, using back-to-back NaI detectors. The incident neutron flux was determined indirectly via 1 H(n,p) protons elastically scattered from the polyethylene target. Previous measurements fall into upper and lower bands; the results of the present measurement are consistent with the upper band.

Neutralino-stop co-annihilation into electroweak gauge and Higgs bosons at one loop

Energy Technology Data Exchange (ETDEWEB)

Harz, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Herrmann, B. [Univ. Savoie/CNRS, Annecy-le-Vieux (France). LAPTh; Klasen, M. [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Kovarik, K. [Karlsruhe Institute of Technology, Karlsruhe (Germany). Inst. for Theoretical Physics; Le Boulc' h, Q. [Grenoble Univ. (France). CNRS-IN2P3/INPG

2012-12-15

We compute the full O({alpha}{sub s}) supersymmetric QCD corrections for neutralino-stop co-annihilation into electroweak gauge and Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM). We show that these annihilation channels are phenomenologically relevant within the so-called phenomenological MSSM, in particular in the light of the observation of a Higgs-like particle with a mass of about 126 GeV at the LHC. We present in detail our calculation, including the renormalization scheme, the infrared treatment, and the kinematical subtleties to be addressed. Numerical results for the co-annihilation cross sections and the predicted neutralino relic density are presented. We demonstrate that the impact of including the corrections on the cosmologically preferred region of parameter space is larger than the current experimental uncertainty from WMAP data.

SEARCH FOR DARK MATTER ANNIHILATION SIGNALS FROM THE FORNAX GALAXY CLUSTER WITH H.E.S.S

Energy Technology Data Exchange (ETDEWEB)

Abramowski, A. [Institut fuer Experimentalphysik, Universitaet Hamburg, Luruper Chaussee 149, D 22761 Hamburg (Germany); Acero, F. [Laboratoire de Physique Theorique et Astroparticules, Universite Montpellier 2, CNRS/IN2P3, CC 70, Place Eugene Bataillon, F-34095 Montpellier Cedex 5 (France); Aharonian, F.; Bernloehr, K.; Bochow, A. [Max-Planck-Institut fuer Kernphysik, P.O. Box 103980, D 69029 Heidelberg (Germany); Akhperjanian, A. G. [National Academy of Sciences of the Republic of Armenia, Yerevan (Armenia); Anton, G.; Balzer, A.; Brucker, J. [Physikalisches Institut, Universitaet Erlangen-Nuernberg, Erwin-Rommel-Str. 1, D 91058 Erlangen (Germany); Barnacka, A. [Nicolaus Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warsaw (Poland); Barres de Almeida, U. [Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Becherini, Y. [Astroparticule et Cosmologie (APC), CNRS, Universite Paris 7 Denis Diderot, 10, rue Alice Domon et Leonie Duquet, F-75205 Paris Cedex 13 (France); Becker, J. [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum und Astrophysik, Ruhr-Universitaet Bochum, D 44780 Bochum (Germany); Behera, B. [Landessternwarte, Universitaet Heidelberg, Koenigstuhl, D 69117 Heidelberg (Germany); Birsin, E. [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstr. 15, D 12489 Berlin (Germany); Biteau, J.; Brun, F. [Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France); Boisson, C. [LUTH, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 Place Jules Janssen, 92190 Meudon (France); Bolmont, J. [LPNHE, Universite Pierre et Marie Curie Paris 6, Universite Denis Diderot Paris 7, CNRS/IN2P3, 4 Place Jussieu, F-75252, Paris Cedex 5 (France); Bordas, P., E-mail: bjoern.opitz@desy.de [Institut fuer Astronomie und Astrophysik, Universitaet Tuebingen, Sand 1, D 72076 Tuebingen (Germany); Collaboration: H.E.S.S. Collaboration; and others

2012-05-10

The Fornax galaxy cluster was observed with the High Energy Stereoscopic System for a total live time of 14.5 hr, searching for very high energy (VHE; E > 100GeV) {gamma}-rays from dark matter (DM) annihilation. No significant signal was found in searches for point-like and extended emissions. Using several models of the DM density distribution, upper limits on the DM velocity-weighted annihilation cross-section ({sigma}v) as a function of the DM particle mass are derived. Constraints are derived for different DM particle models, such as those arising from Kaluza-Klein and supersymmetric models. Various annihilation final states are considered. Possible enhancements of the DM annihilation {gamma}-ray flux, due to DM substructures of the DM host halo, or from the Sommerfeld effect, are studied. Additional {gamma}-ray contributions from internal bremsstrahlung and inverse Compton radiation are also discussed. For a DM particle mass of 1 TeV, the exclusion limits at 95% of confidence level reach values of ({sigma}v){sup 95%C.L.} {approx} 10{sup -23} cm{sup 3} s{sup -1}, depending on the DM particle model and halo properties. Additional contribution from DM substructures can improve the upper limits on ({sigma}v) by more than two orders of magnitude. At masses around 4.5 TeV, the enhancement by substructures and the Sommerfeld resonance effect results in a velocity-weighted annihilation cross-section upper limit at the level of ({sigma}v){sup 95%C.L.} {approx}10{sup -26} cm{sup 3} s{sup -1}.

SEARCH FOR DARK MATTER ANNIHILATION SIGNALS FROM THE FORNAX GALAXY CLUSTER WITH H.E.S.S

International Nuclear Information System (INIS)

Abramowski, A.; Acero, F.; Aharonian, F.; Bernlöhr, K.; Bochow, A.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Brucker, J.; Barnacka, A.; Barres de Almeida, U.; Becherini, Y.; Becker, J.; Behera, B.; Birsin, E.; Biteau, J.; Brun, F.; Boisson, C.; Bolmont, J.; Bordas, P.

2012-01-01

The Fornax galaxy cluster was observed with the High Energy Stereoscopic System for a total live time of 14.5 hr, searching for very high energy (VHE; E > 100GeV) γ-rays from dark matter (DM) annihilation. No significant signal was found in searches for point-like and extended emissions. Using several models of the DM density distribution, upper limits on the DM velocity-weighted annihilation cross-section (σv) as a function of the DM particle mass are derived. Constraints are derived for different DM particle models, such as those arising from Kaluza-Klein and supersymmetric models. Various annihilation final states are considered. Possible enhancements of the DM annihilation γ-ray flux, due to DM substructures of the DM host halo, or from the Sommerfeld effect, are studied. Additional γ-ray contributions from internal bremsstrahlung and inverse Compton radiation are also discussed. For a DM particle mass of 1 TeV, the exclusion limits at 95% of confidence level reach values of (σv) 95%C.L. ∼ 10 –23 cm 3 s –1 , depending on the DM particle model and halo properties. Additional contribution from DM substructures can improve the upper limits on (σv) by more than two orders of magnitude. At masses around 4.5 TeV, the enhancement by substructures and the Sommerfeld resonance effect results in a velocity-weighted annihilation cross-section upper limit at the level of (σv) 95%C.L. ∼10 –26 cm 3 s –1 .

A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the subtraction terms I

Science.gov (United States)

Somogyi, Gábor; Trócsányi, Zoltán

2008-08-01

In previous articles we outlined a subtraction scheme for regularizing doubly-real emission and real-virtual emission in next-to-next-to-leading order (NNLO) calculations of jet cross sections in electron-positron annihilation. In order to find the NNLO correction these subtraction terms have to be integrated over the factorized unresolved phase space and combined with the two-loop corrections. In this paper we perform the integration of all one-parton unresolved subtraction terms.

Lambda production in electron-positron annihilation at 29 GeV

International Nuclear Information System (INIS)

Baden, A.R.

1986-08-01

The inclusive cross-secton for the production of the singly-strange baryons λ and anti λ, along with the differential cross-sections in momentum and energy, are measured by e + e - annihilation at a center-of-mass energy of 29GeV. The charged decay mode λ → pπ is used in a search for polarization. Such a polarization may be used as a check of CP invariance in λ production. The sample of events with two detected decays is analyzed for correlations in production angle. 43 refs., 44 figs

Revisit of cosmic ray antiprotons from dark matter annihilation with updated constraints on the background model from AMS-02 and collider data

Science.gov (United States)

Cui, Ming-Yang; Pan, Xu; Yuan, Qiang; Fan, Yi-Zhong; Zong, Hong-Shi

2018-06-01

We study the cosmic ray antiprotons with updated constraints on the propagation, proton injection, and solar modulation parameters based on the newest AMS-02 data near the Earth and Voyager data in the local interstellar space, and on the cross section of antiproton production due to proton-proton collisions based on new collider data. We use a Bayesian approach to properly consider the uncertainties of the model predictions of both the background and the dark matter (DM) annihilation components of antiprotons. We find that including an extra component of antiprotons from the annihilation of DM particles into a pair of quarks can improve the fit to the AMS-02 antiproton data considerably. The favored mass of DM particles is about 60~100 GeV, and the annihilation cross section is just at the level of the thermal production of DM (langleσvrangle ~ O(10‑26) cm3 s‑1).

Graphs of neutron cross sections in JSD1000 for radiation shielding safety analysis

International Nuclear Information System (INIS)

Yamano, Naoki

1984-03-01

Graphs of neutron cross sections and self-shielding factors in the JSD1000 library are presented for radiation shielding safety analysis. The compilation contains various reaction cross sections for 42 nuclides from 1 H to 241 Am in the energy range from 3.51 x 10 -4 eV to 16.5 MeV. The Bondarenko-type self-shielding factors of each reaction are given by the background cross sections from σ 0 = 0 to σ 0 = 10000. (author)

Prevalence of self-medication among university students in Baghdad: a cross-sectional study from Iraq.

Science.gov (United States)

Al-Ameri, Rawa J K; Abd Al-Badri, Husham J; Lafta, Riyadh K

2017-03-30

The objective of this study is to find out the prevalence and determinants of self-medication among college students in Baghdad, Iraq. A cross-sectional survey was conducted in Al-Mustansiriyah and Al-Nahrain universities, Baghdad, from January to April 2015. A multistage random sampling technique was adopted to collect data from 1435 college students using a questionnaire form. The mean age of the joining students was 19.8 years. Females form 53% of the sample. Self-medications use was prevalent among 92.4% of students. Antipyretics and antibiotics were the most used medicines. Self-medication was higher among urban residents (OR= 7.99, P resilience to self-medication (OR=0.455, P = 0.001). Despite free access to healthcare institutions, nine out of ten college students from Baghdad universities have practiced self-medication. Education of students about the safe use of medications and supervision of pharmacies are effective ways to control this malpractice.

Searching for Dark Matter Annihilation from Milky Way Dwarf Spheroidal Galaxies with Six Years of Fermi Large Area Telescope Data.

Science.gov (United States)

Ackermann, M; Albert, A; Anderson, B; Atwood, W B; Baldini, L; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Bissaldi, E; Blandford, R D; Bloom, E D; Bonino, R; Bottacini, E; Brandt, T J; Bregeon, J; Bruel, P; Buehler, R; Caliandro, G A; Cameron, R A; Caputo, R; Caragiulo, M; Caraveo, P A; Cecchi, C; Charles, E; Chekhtman, A; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cuoco, A; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Desiante, R; Digel, S W; Di Venere, L; Drell, P S; Drlica-Wagner, A; Essig, R; Favuzzi, C; Fegan, S J; Ferrara, E C; Focke, W B; Franckowiak, A; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Gomez-Vargas, G A; Grenier, I A; Guiriec, S; Gustafsson, M; Hays, E; Hewitt, J W; Horan, D; Jogler, T; Jóhannesson, G; Kuss, M; Larsson, S; Latronico, L; Li, J; Li, L; Llena Garde, M; Longo, F; Loparco, F; Lubrano, P; Malyshev, D; Mayer, M; Mazziotta, M N; McEnery, J E; Meyer, M; Michelson, P F; Mizuno, T; Moiseev, A A; Monzani, M E; Morselli, A; Murgia, S; Nuss, E; Ohsugi, T; Orienti, M; Orlando, E; Ormes, J F; Paneque, D; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Porter, T A; Rainò, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Ritz, S; Sánchez-Conde, M; Schulz, A; Sehgal, N; Sgrò, C; Siskind, E J; Spada, F; Spandre, G; Spinelli, P; Strigari, L; Tajima, H; Takahashi, H; Thayer, J B; Tibaldo, L; Torres, D F; Troja, E; Vianello, G; Werner, M; Winer, B L; Wood, K S; Wood, M; Zaharijas, G; Zimmer, S

2015-12-04

The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some of the most dark matter (DM) dominated objects known. We report on γ-ray observations of Milky Way dSphs based on six years of Fermi Large Area Telescope data processed with the new Pass8 event-level analysis. None of the dSphs are significantly detected in γ rays, and we present upper limits on the DM annihilation cross section from a combined analysis of 15 dSphs. These constraints are among the strongest and most robust to date and lie below the canonical thermal relic cross section for DM of mass ≲100  GeV annihilating via quark and τ-lepton channels.

Search for annihilating dark matter in the Sun with 3 years of IceCube data

Energy Technology Data Exchange (ETDEWEB)

Aartsen, M.G.; Hill, G.C.; Robertson, S.; Wallace, A.; Whelan, B.J. [University of Adelaide, Department of Physics, Adelaide (Australia); Ackermann, M.; Bernardini, E.; Blot, S.; Bretz, H.P.; Franckowiak, A.; Jacobi, E.; Karg, T.; Kintscher, T.; Kunwar, S.; Nahnhauer, R.; Satalecka, K.; Spiering, C.; Stasik, A.; Strotjohann, N.L.; Terliuk, A.; Usner, M.; Santen, J. van [DESY, Zeuthen (Germany); Adams, J. [University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch (New Zealand); Aguilar, J.A.; Ansseau, I.; Heereman, D.; Meagher, K.; Meures, T.; O' Murchadha, A.; Pinat, E.; Raab, C. [Universite Libre de Bruxelles, Science Faculty CP230, Brussels (Belgium); Ahlers, M.; Braun, J.; Chirkin, D.; Day, M.; Desiati, P.; Diaz-Velez, J.C.; Fahey, S.; Feintzeig, J.; Ghorbani, K.; Gladstone, L.; Griffith, Z.; Halzen, F.; Hanson, K.; Jero, K.; Karle, A.; Kauer, M.; Kelley, J.L.; Kheirandish, A.; Krueger, C.; Mancina, S.; McNally, F.; Merino, G.; Sabbatini, L.; Tobin, M.N.; Tosi, D.; Vandenbroucke, J.; Van Rossem, M.; Wandkowsky, N.; Wendt, C.; Westerhoff, S.; Wille, L.; Xu, D.L. [University of Wisconsin, Department of Physics and Wisconsin IceCube Particle Astrophysics Center, Madison, WI (United States); Ahrens, M.; Bohm, C.; Dumm, J.P.; Finley, C.; Flis, S.; Hultqvist, K.; Walck, C.; Wolf, M.; Zoll, M. [Stockholm University, Department of Physics, Oskar Klein Centre, Stockholm (Sweden); Altmann, D.; Anton, G.; Gluesenkamp, T.; Katz, U.; Kittler, T.; Tselengidou, M. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Andeen, K. [Marquette University, Department of Physics, Milwaukee, WI (United States); Anderson, T.; Dunkman, M.; Eller, P.; Huang, F.; Keivani, A.; Lanfranchi, J.L.; Pankova, D.V.; Quinnan, M.; Tesic, G.; Weiss, M.J. [Pennsylvania State University, Department of Physics, University Park, PA (United States); Archinger, M.; Baum, V.; Boeser, S.; Pino Rosendo, E. del; Lorenzo, V. di; Eberhardt, B.; Ehrhardt, T.; Foesig, C.C.; Koepke, L.; Krueckl, G.; Peiffer, P.; Sandroos, J.; Steuer, A.; Wiebe, K. [University of Mainz, Institute of Physics, Mainz (Germany); Argueelles, C.; Axani, S.; Collin, G.H.; Conrad, J.M.; Jones, B.J.P.; Moulai, M. [Massachusetts Institute of Technology, Department of Physics, Cambridge, MA (United States); Auffenberg, J.; Bissok, M.; Glauch, T.; Haack, C.; Hansmann, T.; Konietz, R.; Leuermann, M.; Penek, Oe.; Raedel, L.; Reimann, R.; Rongen, M.; Schoenen, S.; Schumacher, L.; Stettner, J.; Vehring, M.; Vogel, E.; Wallraff, M.; Wickmann, S.; Wiebusch, C.H. [RWTH Aachen University, III. Physikalisches Institut, Aachen (Germany); Bai, X. [South Dakota School of Mines and Technology, Physics Department, Rapid City, SD (United States); Barwick, S.W.; Yodh, G. [University of California, Department of Physics and Astronomy, Irvine, CA (United States); Bay, R.; Filimonov, K.; Price, P.B.; Woschnagg, K. [University of California, Department of Physics, Berkeley, CA (United States); Beatty, J.J. [Ohio State University, Department of Physics and Center for Cosmology and Astro-Particle Physics, Columbus, OH (United States); Ohio State University, Department of Astronomy, Columbus, OH (United States); Becker Tjus, J.; Bos, F.; Eichmann, B.; Kroll, M.; Mandelartz, M.; Schoeneberg, S.; Tenholt, F. [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Bochum (Germany); Becker, K.H.; Bindig, D.; Helbing, K.; Hickford, S.; Hoffmann, R.; Kopper, S.; Lauber, F.; Naumann, U.; Obertacke Pollmann, A.; Soldin, D. [University of Wuppertal, Department of Physics, Wuppertal (Germany); BenZvi, S.; Cross, R. [University of Rochester, Department of Physics and Astronomy, Rochester, NY (United States); Berley, D.; Blaufuss, E.; Cheung, E.; Felde, J.; Friedman, E.; Hellauer, R.; Hoffman, K.D.; Maunu, R.; Olivas, A.; Schmidt, T.; Song, M.; Sullivan, G.W. [University of Maryland, Department of Physics, College Park, MD (United States); Bernhard, A.; Coenders, S.; Huber, M.; Krings, K.; Resconi, E.; Turcati, A. [Technische Universitaet Muenchen, Physik-Department, Garching (Germany); Besson, D.Z. [University of Kansas, Department of Physics and Astronomy, Lawrence, KS (United States); Binder, G.; Gerhardt, L.; Klein, S.R.; Miarecki, S.; Palczewski, T.; Tatar, J. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Boerner, M.; Fuchs, T.; Meier, M.; Menne, T.; Pieloth, D.; Rhode, W.; Ruhe, T.; Sandrock, A.; Schlunder, P. [TU Dortmund University, Department of Physics, Dortmund (Germany); Bose, D.; Dujmovic, H.; In, S.; Jeong, M.; Kang, W.; Kim, J.; Kim, M.; Rott, C. [Sungkyunkwan University, Department of Physics, Suwon (Korea, Republic of); Collaboration: IceCube Collaboration; and others

2017-03-15

We present results from an analysis looking for dark matter annihilation in the Sun with the IceCube neutrino telescope. Gravitationally trapped dark matter in the Sun's core can annihilate into Standard Model particles making the Sun a source of GeV neutrinos. IceCube is able to detect neutrinos with energies >100 GeV while its low-energy infill array DeepCore extends this to >10 GeV. This analysis uses data gathered in the austral winters between May 2011 and May 2014, corresponding to 532 days of live time when the Sun, being below the horizon, is a source of up-going neutrino events, easiest to discriminate against the dominant background of atmospheric muons. The sensitivity is a factor of two to four better than previous searches due to additional statistics and improved analysis methods involving better background rejection and reconstructions. The resultant upper limits on the spin-dependent dark matter-proton scattering cross section reach down to 1.46 x 10{sup -5} pb for a dark matter particle of mass 500 GeV annihilating exclusively into τ{sup +}τ{sup -} particles. These are currently the most stringent limits on the spin-dependent dark matter-proton scattering cross section for WIMP masses above 50 GeV. (orig.)

Measurement of hadronic exclusive cross sections in e+e- annihilation from 1.42 to 2.20 GeV

International Nuclear Information System (INIS)

Bacci, C.; De Zorzi, G.; Penso, G.; Stella, B.; Baldini Celio, R.; Battistoni, G.; Capon, G.; Del Fabbro, R.; Iarocci, E.; Murtas, G.P.

1981-01-01

Total cross sections for reactions e + e - → π + π - π 0 , π + π - 2π 0 , 2π + 2π - π 0 , 2π + 2π - 2π 0 , 3π + 3π - have been measured in the total c.m. energy range 1.42-2.20 GeV. Partial R = sigmasub(had)/sigmasub(μ + μ - ) values for two and four produced charged pions, and cross sections for positive and negative G-parity states are also reported. (orig.)

A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the doubly unresolved subtraction terms

Science.gov (United States)

Somogyi, Gábor

2013-04-01

We finish the definition of a subtraction scheme for computing NNLO corrections to QCD jet cross sections. In particular, we perform the integration of the soft-type contributions to the doubly unresolved counterterms via the method of Mellin-Barnes representations. With these final ingredients in place, the definition of the scheme is complete and the computation of fully differential rates for electron-positron annihilation into two and three jets at NNLO accuracy becomes feasible.

A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the doubly unresolved subtraction terms

OpenAIRE

Somogyi, Gabor

2013-01-01

We finish the definition of a subtraction scheme for computing NNLO corrections to QCD jet cross sections. In particular, we perform the integration of the soft-type contributions to the doubly unresolved counterterms via the method of Mellin-Barnes representations. With these final ingredients in place, the definition of the scheme is complete and the computation of fully differential rates for electron-positron annihilation into two and three jets at NNLO accuracy becomes feasible.

Molecular model for annihilation rates in positron complexes

Energy Technology Data Exchange (ETDEWEB)

Assafrao, Denise [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, P.O. Box 702, 30123-970 Belo Horizonte, MG (Brazil); Department of Applied Mathematics and Theoretical Physics, Queen' s University of Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom); Walters, H.R. James [Department of Applied Mathematics and Theoretical Physics, Queen' s University of Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom); Mohallem, Jose R. [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, P.O. Box 702, 30123-970 Belo Horizonte, MG (Brazil); Department of Applied Mathematics and Theoretical Physics, Queen' s University of Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom)], E-mail: rachid@fisica.ufmg.br

2008-02-15

The molecular approach for positron interaction with atoms is developed further. Potential energy curves for positron motion are obtained. Two procedures accounting for the nonadiabatic effective positron mass are introduced for calculating annihilation rate constants. The first one takes the bound-state energy eigenvalue as an input parameter. The second is a self-contained and self-consistent procedure. The methods are tested with quite different states of the small complexes HPs, e{sup +}He (electronic triplet) and e{sup +}Be (electronic singlet and triplet). For states yielding the positronium cluster, the annihilation rates are quite stable, irrespective of the accuracy in binding energies. For the e{sup +}Be states, annihilation rates are larger and more consistent with qualitative predictions than previously reported ones.

Molecular model for annihilation rates in positron complexes

International Nuclear Information System (INIS)

Assafrao, Denise; Walters, H.R. James; Mohallem, Jose R.

2008-01-01

The molecular approach for positron interaction with atoms is developed further. Potential energy curves for positron motion are obtained. Two procedures accounting for the nonadiabatic effective positron mass are introduced for calculating annihilation rate constants. The first one takes the bound-state energy eigenvalue as an input parameter. The second is a self-contained and self-consistent procedure. The methods are tested with quite different states of the small complexes HPs, e + He (electronic triplet) and e + Be (electronic singlet and triplet). For states yielding the positronium cluster, the annihilation rates are quite stable, irrespective of the accuracy in binding energies. For the e + Be states, annihilation rates are larger and more consistent with qualitative predictions than previously reported ones

On the New Scenario of Annihilation of the Cross-Well Chaotic Attractor in a Nonlinear Oscillator

International Nuclear Information System (INIS)

Szemplinska, W.; Zubrzycki, A.; Tyrkiel, E.

1999-01-01

The twin-well potential Duffing oscillator is considered and the investigations are focused on a new scenario of destruction of the cross-well chaotic attractor. The new phenomenon belongs to the category of subduction bifurcation and consists in replacement of the cross-well chaotic attractor by a pair of unsymmetric 2T-periodic attractors. It is shown that the new scenario forms a transition zone in the system control parameter plane, the zone, which separates the two known scenarios of annihilation of the cross-well chaotic attractor: the boundary crisis, and the subduction in which the two single-well T-periodic attractors are born in a saddle-node bifurcation. (author)

Testing a self-determination theory model of children’s physical activity motivation: a cross-sectional study

Science.gov (United States)

2013-01-01

Background Understanding children’s physical activity motivation, its antecedents and associations with behavior is important and can be advanced by using self-determination theory. However, research among youth is largely restricted to adolescents and studies of motivation within certain contexts (e.g., physical education). There are no measures of self-determination theory constructs (physical activity motivation or psychological need satisfaction) for use among children and no previous studies have tested a self-determination theory-based model of children’s physical activity motivation. The purpose of this study was to test the reliability and validity of scores derived from scales adapted to measure self-determination theory constructs among children and test a motivational model predicting accelerometer-derived physical activity. Methods Cross-sectional data from 462 children aged 7 to 11 years from 20 primary schools in Bristol, UK were analysed. Confirmatory factor analysis was used to examine the construct validity of adapted behavioral regulation and psychological need satisfaction scales. Structural equation modelling was used to test cross-sectional associations between psychological need satisfaction, motivation types and physical activity assessed by accelerometer. Results The construct validity and reliability of the motivation and psychological need satisfaction measures were supported. Structural equation modelling provided evidence for a motivational model in which psychological need satisfaction was positively associated with intrinsic and identified motivation types and intrinsic motivation was positively associated with children’s minutes in moderate-to-vigorous physical activity. Conclusions The study provides evidence for the psychometric properties of measures of motivation aligned with self-determination theory among children. Children’s motivation that is based on enjoyment and inherent satisfaction of physical activity is

Ethnicity and self-perceived oral health in Colombia: a cross-sectional analysis.

Science.gov (United States)

Agudelo-Suárez, Andrés A; Martínez-Herrera, Eliana; Posada-López, Adriana; Sánchez-Patiño, Danilo; Viñas-Sarmiento, Yomaira

2014-02-01

To estimate the association between self-perceived oral health indicators and ethnic origin in Colombia, a cross-sectional study (Information from the 2007 National Public Health Survey) was conducted. belonging to an ethnic group (Exposure); oral health indicators (Outcomes); sex, age, education and self-rated health (control). Analyses were carried out separately for men (M) and women (W). The association between the exposure variable and the outcomes was estimated by means of adjusted odds ratio (OR) with confidence intervals (95% CI) using logistic regression. Men were more likely to report gum bleeding (aOR 1.78; 95% CI 1.44-2.23) and dental caries (aOR 1.69; 95% CI 1.42-2.02), while women were more likely to report unmet dental needs (aOR 1.43; 95% CI 1.27-1.49) and dental caries (aOR 1.34; 95% CI 1.22-1.47). Indigenous and Palenquero were more likely to report most of the indicators analyzed. Minority ethnic groups in Colombia were at risk to report oral health problems.

Reggeon, Pomeron and annihilation processes in the dual unitarization scheme

International Nuclear Information System (INIS)

Dias de Deus, J.

1976-07-01

In the framework of the dual unitarization scheme the connection between particle production in processes dominated by Reggeon, Pomeron and Annihilation diagrams is discussed and critical tests of the scheme are suggested. The simple relation for average multiplicities anti nsup(R) = 1/2 anti nsup(P) = 1/3 anti nsup(A) and other relations for inclusive cross-sections and higher moments of the particle distribution are shown to be in reasonable agreement with data. (author)

Evidence for iota production in high energy e+e--annihilation

International Nuclear Information System (INIS)

Bartel, W.; Becker, L.; Cords, D.; Felst, R.; Haidt, D.; Knies, G.; Krehbiel, H.; Meinke, R.; Naroska, B.; Olsson, J.; Steffen, P.; Laurikainen, P.; Magnussen, N.; Schmidt, D.; Dietrich, G.; Hagemann, J.; Heinzelmann, G.; Kado, H.; Kawagoe, K.; Kleinwort, C.; Kuhlen, M.; Petersen, A.; Ramcke, R.; Schneekloth, U.; Weber, G.; Allison, J.; Ball, A.H.; Barlow, R.J.; Chrin, J.; Duerdoth, I.P.; Greenshaw, T.; Hill, P.; Loebinger, F.K.; Macbeth, A.A.; Mills, H.E.; Murphy, P.G.; Stephens, K.; Warming, P.; Glasser, R.G.; Skard, J.A.J.; Wagner, S.R.; Zorn, G.T.; Cartwright, S.L.; Clarke, D.; Marshall, R.; Middleton, R.P.; Kawamoto, T.; Kobayashi, T.; Takeda, H.; Takeshita, T.; Yamada, S.

1985-08-01

The inclusive production of iota mesons in e + e - -annihilations at √sproportional 36.0 GeV is investigated with the JADE detector at PETRA. 13 candidates for the l(1440) state are reconstructed through their decay into Ksub(s) 0 Ksup(+-)πsup(-+). A cross section (times branching ratio) of sigma.B=4.7+-1.3+-1.7 pb is observed. Within the errors the iota yield is independent of the event shape. (orig.)

Nuclear characteristics of Pu fueled LWR and cross section sensitivities

Energy Technology Data Exchange (ETDEWEB)

Takeda, Toshikazu [Osaka Univ., Suita (Japan). Faculty of Engineering

1998-03-01

The present status of Pu utilization to thermal reactors in Japan, nuclear characteristics and topics and cross section sensitivities for analysis of Pu fueled thermal reactors are described. As topics we will discuss the spatial self-shielding effect on the Doppler reactivity effect and the cross section sensitivities with the JENDL-3.1 and 3.2 libraries. (author)

Factors associated with self-medication in Spain: a cross-sectional study in different age groups.

Science.gov (United States)

Niclós, Gracia; Olivar, Teresa; Rodilla, Vicent

2018-06-01

The identification of factors which may influence a patient's decision to self-medicate. Descriptive, cross-sectional study of the adult population (at least 16 years old), using data from the 2009 European Health Interview Survey in Spain, which included 22 188 subjects. Logistic regression models enabled us to estimate the effect of each analysed variable on self-medication. In total, 14 863 (67%) individuals reported using medication (prescribed and non-prescribed) and 3274 (22.0%) of them self-medicated. Using logistic regression and stratifying by age, four different models have been constructed. Our results include different variables in each of the models to explain self-medication, but the one that appears on all four models is education level. Age is the other important factor which influences self-medication. Self-medication is strongly associated with factors related to socio-demographic, such as sex, educational level or age, as well as several health factors such as long-standing illness or physical activity. When our data are compared to those from previous Spanish surveys carried out in 2003 and 2006, we can conclude that self-medication is increasing in Spain. © 2017 Royal Pharmaceutical Society.

Factors associated with self-esteem in persons with morbid obesity and in persons with chronic obstructive pulmonary disease: A cross-sectional study

OpenAIRE

Bonsaksen, Tore; Fagermoen, May Solveig; Lerdal, Anners

2014-01-01

Living with chronic illnesses can be stressful and may negatively impact persons’ self-esteem. Personal factors, like self-efficacy and illness perceptions, and also factors related to the environment, activity, and participation may be associated with self-esteem in chronic illness populations. This cross-sectional comparative study explored sociodemographic variables, work, physical activity, illness perceptions, and general self-efficacy in relation to self-esteem in persons with morbid ob...

Association between Self-Reported Bruxism and Sleeping Patterns among Dental Students in Saudi Arabia: A Cross-Sectional Study.

Science.gov (United States)

Shokry, Shereen M; El Wakeel, Eman E; Al-Maflehi, Nassr; RasRas, Zaheera; Fataftah, Nida; Abdul Kareem, Enam

2016-01-01

Objectives. The aim of this cross-sectional study was to identify sleeping patterns among dental students and their association with self-reported bruxism in Riyadh Colleges of Dentistry and Pharmacy (RCsDP). Methods. A cross-sectional study was performed including 549 students (67 men and 482 women). A structured questionnaire was adopted from The PSQI (The Pittsburgh Sleep Questionnaire Index) used for data collection. It included questions which are categorized into sleeping habits, sleep-related symptoms, and additional questions concerning bruxism. This questionnaire was randomly distributed among all college preclinical and postclinical students. Sleep bruxism diagnosis was based on self-reported data. The data were analyzed using Chi-square tests through SPSS software for Windows. Results. Statistical analyses revealed significant correlations between self-reported bruxism and sleeping habits including sleep initiation (χ (2) = 22.6, p = 0.000), continuous sleep until morning (χ (2) = 19.2, p = 0.001), nighttime sleep duration (χ (2) = 20.2, p = 0.000), and length of daytime naps (χ (2) = 28.35, p = 0.000). There was an association between self-reported bruxism and sleeping-related symptoms including awakening early in the morning before the usual time without a cause (χ (2) = 16.52, p = 0.000) and increased nightmares (χ (2) = 13.7, p = 0.001). Conclusions. Poor sleeping pattern was an important factor among dental students, who reported sleep bruxism.

Association between Self-Reported Bruxism and Sleeping Patterns among Dental Students in Saudi Arabia: A Cross-Sectional Study

Directory of Open Access Journals (Sweden)

Shereen M. Shokry

2016-01-01

Full Text Available Objectives. The aim of this cross-sectional study was to identify sleeping patterns among dental students and their association with self-reported bruxism in Riyadh Colleges of Dentistry and Pharmacy (RCsDP. Methods. A cross-sectional study was performed including 549 students (67 men and 482 women. A structured questionnaire was adopted from The PSQI (The Pittsburgh Sleep Questionnaire Index used for data collection. It included questions which are categorized into sleeping habits, sleep-related symptoms, and additional questions concerning bruxism. This questionnaire was randomly distributed among all college preclinical and postclinical students. Sleep bruxism diagnosis was based on self-reported data. The data were analyzed using Chi-square tests through SPSS software for Windows. Results. Statistical analyses revealed significant correlations between self-reported bruxism and sleeping habits including sleep initiation (χ2=22.6, p=0.000, continuous sleep until morning (χ2=19.2, p=0.001, nighttime sleep duration (χ2=20.2, p=0.000, and length of daytime naps (χ2=28.35, p=0.000. There was an association between self-reported bruxism and sleeping-related symptoms including awakening early in the morning before the usual time without a cause (χ2=16.52, p=0.000 and increased nightmares (χ2=13.7, p=0.001. Conclusions. Poor sleeping pattern was an important factor among dental students, who reported sleep bruxism.

QCD corrections to squark production in e+ e- annihilation in the MSSM with complex parameters

International Nuclear Information System (INIS)

Nguyen Thi Thu Huong; Ha Huy Bang; Nguyen Chinh Cuong; Dao Thi Le Thuy

2004-11-01

We discuss the pair production of scalar quarks in e + e - annihilation within the MSSM with complex parameters. We calculate the SUSY-QCD corrections to the cross section e + e - → q-tilde i q-bar-tilde j (i, j 1, 2) and show that the effect of the CP phases of these complex parameters on the cross section can be quite strong in a large region of the MSSM parameter space. This could have important implications for squarks searches and the MSSM parameter determination in future collider experiments. (author)

Is quark-antiquark annihilation infrared safe at high energy

International Nuclear Information System (INIS)

Frenkel, J.; Gatheral, J.G.M.; Taylor, J.C.

1983-01-01

In perturbative QCD, the Bloch-Nordsieck cross section for quark-antiquark annihilation is known, to order g 4 , to be infrared finite, except for terms which are power suppressed at high energies. A fairly simple explanation of this fact, using analyticity, unitarity and an analysis of mass-singularities in both Feynman and axial gauges, is given. The argument applies fairly easily to order g 6 . Assuming a generalized unitarity principle, the argument can be extended to all orders. (Author) [pt

Cross-section fluctuations and self-shielding effects in the unresolved resonance region - International Evaluation Co-operation volume 15

International Nuclear Information System (INIS)

Froehner, F.H.; Larson, Duane C.; Tagesen, Siegfried; Petrizzi, Luigi; Hasegawa, Akira; Nakagawa, Tsuneo; Hogenbirk, Alfred; Weigmann, H.

1995-01-01

A Working Party on International Evaluation Co-operation was established under the sponsorship of the OECD/NEA Nuclear Science Committee (NSC) to promote the exchange of information on nuclear data evaluations, validation, and related topics. Its aim is also to provide a framework for co-operative activities between members of the major nuclear data evaluation projects. This includes the possible exchange of scientists in order to encourage co-operation. Requirements for experimental data resulting from this activity are compiled. The Working Party determines common criteria for evaluated nuclear data files with a view to assessing and improving the quality and completeness of evaluated data. The Parties to the project are: ENDF (United States), JEFF/EFF (NEA Data Bank Member countries), and JENDL (Japan). Co-operation with evaluation projects of non-OECD countries are organised through the Nuclear Data Section of the International Atomic Energy Agency (IAEA). NEA/NSC Subgroup 15 has had the task to assess self-shielding effects in the unresolved resonance range of structural materials, in particular their importance at various energies, and possible ways to deal with them in shielding and activation work. The principal results achieved are summarised briefly, in particular: - New data base consisting of high-resolution transmission data measured at Oak Ridge and Geel; - Improved theoretical understanding of cross-section fluctuations, including their prediction, that has been derived from the Hauser-Feshbach theory; - Benchmark results on the importance of self-shielding in iron at various energies; - Consequences for information storage in evaluated nuclear data files; - Practical utilisation of self-shielding information from evaluated files. Benchmark results as well as the Hauser-Feshbach theory show that self-shielding effects are important up to a 4-or 5-MeV neutron energy. Fluctuation factors extracted from high-resolution total cross-section data can be

Search for right-handed neutrinos from dark matter annihilation with gamma-rays

Energy Technology Data Exchange (ETDEWEB)

Campos, Miguel D.; Queiroz, Farinaldo S.; Yaguna, Carlos E. [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Weniger, Christoph, E-mail: miguel.campos@mpi-hd.mpg.de, E-mail: farinaldo.queiroz@mpi-hd.mpg.de, E-mail: carlos.yaguna@uptc.edu.co, E-mail: c.weniger@uva.nl [GRAPPA, Institute of Physics, University of Amsterdam, Science Park 904, 1090 GL Amsterdam (Netherlands)

2017-07-01

Several extensions of the Standard Model contain right-handed (sterile) neutrinos in the GeV-TeV mass range. Due to their mixing with the active neutrinos, they may give rise to novel effects in cosmology, neutrino physics, and collider searches. In addition, right-handed neutrinos can also appear as final states from dark matter annihilations, with important implications for dark matter indirect detection searches. In this paper, we use current data from the Fermi Large Area Telescope (6-year observation of dwarf spheroidal galaxies) and H.E.S.S. (10-year observation of the Galactic center) to constrain the annihilation of dark matter into right-handed neutrinos. We consider right-handed neutrino with masses between 10 GeV and 1 TeV, including both two-body and three-body decays, to derive bounds on the dark matter annihilation rate, ( σ v ), as a function of the dark matter mass. Our results show, in particular, that the thermal dark matter annihilation cross section, 3× 10{sup −26} cm{sup 3} s {sup −1} , into right-handed neutrinos is excluded for dark matter masses smaller than 200 GeV.

Search for right-handed neutrinos from dark matter annihilation with gamma-rays

International Nuclear Information System (INIS)

Campos, Miguel D.; Queiroz, Farinaldo S.; Yaguna, Carlos E.; Weniger, Christoph

2017-01-01

Several extensions of the Standard Model contain right-handed (sterile) neutrinos in the GeV-TeV mass range. Due to their mixing with the active neutrinos, they may give rise to novel effects in cosmology, neutrino physics, and collider searches. In addition, right-handed neutrinos can also appear as final states from dark matter annihilations, with important implications for dark matter indirect detection searches. In this paper, we use current data from the Fermi Large Area Telescope (6-year observation of dwarf spheroidal galaxies) and H.E.S.S. (10-year observation of the Galactic center) to constrain the annihilation of dark matter into right-handed neutrinos. We consider right-handed neutrino with masses between 10 GeV and 1 TeV, including both two-body and three-body decays, to derive bounds on the dark matter annihilation rate, ( σ v ), as a function of the dark matter mass. Our results show, in particular, that the thermal dark matter annihilation cross section, 3× 10 −26 cm 3 s −1 , into right-handed neutrinos is excluded for dark matter masses smaller than 200 GeV.

Radar cross section

CERN Document Server

Knott, Gene; Tuley, Michael

2004-01-01

This is the second edition of the first and foremost book on this subject for self-study, training, and course work. Radar cross section (RCS) is a comparison of two radar signal strengths. One is the strength of the radar beam sweeping over a target, the other is the strength of the reflected echo sensed by the receiver. This book shows how the RCS ?gauge? can be predicted for theoretical objects and how it can be measured for real targets. Predicting RCS is not easy, even for simple objects like spheres or cylinders, but this book explains the two ?exact? forms of theory so well that even a

MC²-3: Multigroup Cross Section Generation Code for Fast Reactor Analysis

Energy Technology Data Exchange (ETDEWEB)

Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States); Yang, W. S. [Argonne National Lab. (ANL), Argonne, IL (United States)

2013-11-08

The MC²-3 code is a Multigroup Cross section generation Code for fast reactor analysis, developed by improving the resonance self-shielding and spectrum calculation methods of MC²-2 and integrating the one-dimensional cell calculation capabilities of SDX. The code solves the consistent P1 multigroup transport equation using basic neutron data from ENDF/B data files to determine the fundamental mode spectra for use in generating multigroup neutron cross sections. A homogeneous medium or a heterogeneous slab or cylindrical unit cell problem is solved in ultrafine (~2000) or hyperfine (~400,000) group levels. In the resolved resonance range, pointwise cross sections are reconstructed with Doppler broadening at specified isotopic temperatures. The pointwise cross sections are directly used in the hyperfine group calculation whereas for the ultrafine group calculation, self-shielded cross sections are prepared by numerical integration of the pointwise cross sections based upon the narrow resonance approximation. For both the hyperfine and ultrafine group calculations, unresolved resonances are self-shielded using the analytic resonance integral method. The ultrafine group calculation can also be performed for two-dimensional whole-core problems to generate region-dependent broad-group cross sections. Multigroup cross sections are written in the ISOTXS format for a user-specified group structure. The code is executable on UNIX, Linux, and PC Windows systems, and its library includes all isotopes of the ENDF/BVII. 0 data.

The convolution integral for the forward-backward asymmetry in e+e- annihilation

International Nuclear Information System (INIS)

Bardin, D.; Bilenky, M.; Chizhov, A.; Sazonov, A.; Sedykh, Yu.; Riemann, T.; Sachwitz, M.

1989-01-01

The complete convolution integral for the forward-backward asymmetry in A FB in e + e - annihilation is obtained in order O(α) with soft photon exponentiation. The influence of these QED corrections on A FB in the vicinity of the Z peak is discussed. The results are used to comment on a recent ad hoc ansatz using convolution weights derived for the total cross section. (orig.)

Relationship of self-liking, self-competence with self-reported oral health status among 15-year-old children of Davangere city: A cross-sectional survey

Directory of Open Access Journals (Sweden)

Anjan Giriraju

2015-01-01

Full Text Available Introduction: Psychological constructs have been found to have potential effects in the improvement of health. Self-esteem (expressed in the form of sub-constructs: Self-liking and self-competence is a construct, which makes one realize the self. This in turn will result in positive oral-health-seeking behavior and improvement in oral health status. Aim: To assess the relationship of self-liking, self-competence with self-reported oral health status in children aged 15 years, in Davangere city. Materials and Methods: A descriptive, cross-sectional survey was conducted on 220 15-year-old subjects in Davangere City. Specially designed pro forma containing Romanian self-administered questionnaire to record the self-reported oral health status and Tafarodi's SLC scale to measure self-liking/self-competence was used. Chi-square test was used for statistical analysis. Results: A majority of the participants were found to have moderate self-competence and self-liking and their self-reported oral health status was expressed as "excellent." They reported very less or no untreated decayed teeth and no extracted teeth or gingival bleeding. Conclusion: The participants with better self-competence and self-liking perceived their oral health status as good. They reported lesser incidence of oral diseases and discomfort. Self-esteem and oral health were found to be positively related.

Invariant cross sections for the inclusive reactions antipp→π++X and antipp→p+X at 22.4 GeV/c

International Nuclear Information System (INIS)

Boss, E.G.; Ermilova, D.I.; Samojlov, V.V.

1978-01-01

The invariant inclusive cross sections for π + mesons and protons from antipp reactions at 22.4 GeV/c are presented. The average multiplicity for π + meson and proton production is 1.92+-0.02 and 0.41+-0.02, respectively. The annihilation spectra have been approximated using the difference between antipp and pp data. The resulting distributions have similar features as the total antipp data

All-flavour search for neutrinos from dark matter annihilations in the Milky Way with IceCube/DeepCore

Energy Technology Data Exchange (ETDEWEB)

Aartsen, M.G.; Hill, G.C.; Robertson, S.; Wallace, A.; Whelan, B.J. [University of Adelaide, Department of Physics, Adelaide (Australia); Abraham, K.; Bernhard, A.; Coenders, S.; Holzapfel, K.; Huber, M.; Jurkovic, M.; Krings, K.; Resconi, E.; Turcati, A.; Veenkamp, J. [Technische Universitaet Muenchen, Physik-department, Garching (Germany); Ackermann, M.; Bernardini, E.; Blot, S.; Bretz, H.P.; Cruz Silva, A.H.; Franckowiak, A.; Gluesenkamp, T.; Gora, D.; Jacobi, E.; Karg, T.; Kintscher, T.; Kunwar, S.; Middell, E.; Mohrmann, L.; Nahnhauer, R.; Satalecka, K.; Schoenwald, A.; Spiering, C.; Stasik, A.; Stoessl, A.; Strotjohann, N.L.; Terliuk, A.; Usner, M.; Santen, J. van; Yanez, J.P. [DESY, Zeuthen (Germany); Adams, J. [University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch (New Zealand); Aguilar, J.A.; Ansseau, I.; Heereman, D.; Meagher, K.; Meures, T.; O' Murchadha, A.; Pinat, E.; Raab, C. [Universite Libre de Bruxelles, Science Faculty CP230, Brussels (Belgium); Ahlers, M.; Braun, J.; Chirkin, D.; Day, M.; Desiati, P.; Diaz-Velez, J.C.; Fahey, S.; Feintzeig, J.; Ghorbani, K.; Gladstone, L.; Griffith, Z.; Halzen, F.; Hanson, K.; Hoshina, K.; Jero, K.; Karle, A.; Kelley, J.L.; Kheirandish, A.; Krueger, C.; Mancina, S.; McNally, F.; Merino, G.; Sabbatini, L.; Tobin, M.N.; Tosi, D.; Vandenbroucke, J.; Van Rossem, M.; Wandkowsky, N.; Wendt, C.; Westerhoff, S.; Wille, L.; Xu, D.L. [University of Wisconsin, Department of Physics, Wisconsin IceCube Particle Astrophysics Center, Madison, WI (United States); Ahrens, M.; Bohm, C.; Dumm, J.P.; Finley, C.; Flis, S.; Hultqvist, K.; Walck, C.; Wolf, M.; Zoll, M. [Stockholm University, Department of Physics, Oskar Klein Centre, Stockholm (Sweden); Altmann, D.; Anton, G.; Katz, U.; Kittler, T.; Tselengidou, M. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Andeen, K. [Marquette University, Department of Physics, Milwaukee, WI (United States); Anderson, T.; Arlen, T.C.; Dunkman, M.; Huang, F.; Keivani, A.; Lanfranchi, J.L.; Pankova, D.V.; Quinnan, M.; Tesic, G. [Pennsylvania State University, Department of Physics, University Park, PA (United States); Archinger, M.; Baum, V.; Boeser, S.; Del Pino Rosendo, E.; Di Lorenzo, V.; Eberhardt, B.; Ehrhardt, T.; Foesig, C.C.; Koepke, L.; Krueckl, G.; Sandroos, J.; Steuer, A.; Wiebe, K. [University of Mainz, Institute of Physics, Mainz (Germany); Arguelles, C.; Axani, S.; Collin, G.H.; Conrad, J.M.; Jones, B.J.P.; Moulai, M. [Massachusetts Institute of Technology, Department of Physics, Cambridge, MA (United States); Auffenberg, J.; Bissok, M.; Glagla, M.; Haack, C.; Hansmann, B.; Hansmann, T.; Kemp, J.; Konietz, R.; Leuermann, M.; Leuner, J.; Penek, Oe.; Raedel, L.; Reimann, R.; Rongen, M.; Schimp, M.; Schoenen, S.; Schumacher, L.; Stahlberg, M.; Vehring, M.; Wallraff, M.; Wickmann, S.; Wiebusch, C.H. [RWTH Aachen University, III. Physikalisches Institut, Aachen (Germany); Bai, X. [South Dakota School of Mines and Technology, Physics Department, Rapid City, SD (United States); Barwick, S.W.; Yodh, G. [University of California, Department of Physics and Astronomy, Irvine, CA (United States); Bay, R.; Filimonov, K.; Price, P.B.; Woschnagg, K. [University of California, Department of Physics, Berkeley, CA (United States); Beatty, J.J. [Ohio State University, Department of Physics, Center for Cosmology and Astro-Particle Physics, Columbus, OH (United States); Ohio State University, Department of Astronomy, Columbus, OH (United States); Becker Tjus, J.; Bos, F.; Eichmann, B.; Kroll, M.; Mandelartz, M.; Schoeneberg, S.; Tenholt, F. [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Bochum (Germany); Becker, K.H.; Bindig, D.; Helbing, K.; Hickford, S.; Hoffmann, R.; Kopper, S.; Naumann, U.; Obertacke Pollmann, A.; Omairat, A.; Posselt, J.; Soldin, D. [University of Wuppertal, Department of Physics, Wuppertal (Germany); BenZvi, S. [University of Rochester, Department of Physics and Astronomy, Rochester, NY (United States); Berghaus, P. [National Research Nuclear University, Moscow Engineering Physics Institute (MEPhI), Moscow (Russian Federation); Berley, D.; Blaufuss, E.; Cheung, E.; Felde, J.; Hellauer, R.; Hoffman, K.D.; Huelsnitz, W.; Maunu, R.; Olivas, A.; Schmidt, T.; Song, M.; Sullivan, G.W.; Wissing, H. [University of Maryland, Department of Physics, College Park, MD (United States); Besson, D.Z. [University of Kansas, Department of Physics and Astronomy, Lawrence, KS (United States); Binder, G.; Gerhardt, L.; Klein, S.R.; Miarecki, S.; Tatar, J. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); and others

2016-10-15

We present the first IceCube search for a signal of dark matter annihilations in the Milky Way using all-flavour neutrino-induced particle cascades. The analysis focuses on the DeepCore sub-detector of IceCube, and uses the surrounding IceCube strings as a veto region in order to select starting events in the DeepCore volume. We use 329 live-days of data from IceCube operating in its 86-string configuration during 2011-2012. No neutrino excess is found, the final result being compatible with the background-only hypothesis. From this null result, we derive upper limits on the velocity-averaged self-annihilation cross-section, left angle σ{sub A}v right angle, for dark matter candidate masses ranging from 30 GeV up to 10 TeV, assuming both a cuspy and a flat-cored dark matter halo profile. For dark matter masses between 200 GeV and 10 TeV, the results improve on all previous IceCube results on left angle σ{sub A}v right angle, reaching a level of 10{sup -23} cm{sup 3} s {sup -1}, depending on the annihilation channel assumed, for a cusped NFW profile. The analysis demonstrates that all-flavour searches are competitive with muon channel searches despite the intrinsically worse angular resolution of cascades compared to muon tracks in IceCube. (orig.)

Obese Chinese Primary-School Students and Low Self-Esteem: A Cross-Sectional Study.

Science.gov (United States)

Xue-Yan, Zhang; Dong-Mei, Li; Dan-Dan, Xu; Le-Shan, Zhou

2016-08-01

The aim of this study was to examine several factors related to low self-esteem among obese Chinese primary-school students. A cross-sectional study was conducted between June 2009 and June 2010. A total of 1,410 primary-school students (China grades 4 - 6) in Changsha city were divided into normal weight (n = 1,084), overweight (n = 211), and obese groups (n = 115) according to world health organization (WHO) growth standards for body mass index (BMI). The students were assessed using the self-esteem scale (SES) and a general situation questionnaire. Caregivers completed questionnaires about their child's weight status. Self-esteem levels were explored; any factors related to low self-esteem were analyzed using logistic regression analysis. The average self-esteem score among overweight or obese primary-school students was found to be lower than that of normal-weight students. The proportion of students with low self-esteem in the obese group was more than that in the normal-weight and overweight groups. Multiple logistic regression analysis showed that obesity status (odds ratio [OR], 3.74; 95% confidence interval [CI], 2.25 - 6.22), overweight status (OR, 2.60; 95% CI, 1.71 - 3.95), obesity considered by children's grandparents (OR, 1.76; 95% CI, 1.05 - 2.96), dissatisfaction with height (OR, 1.55; 95% CI, 1.11 - 2.18), and dissatisfaction with weight (OR, 1.45; 95% CI, 1.05 - 2.01) were the risk factors for low self-esteem for primary-school students, while satisfaction with academic performance was a protective factor (OR, 0.22; 95% CI, 0.07 - 0.71). For Chinese primary-school students, low self-esteem is associated with higher weight status and self-perceived body shape and academic performance. In addition, grandparental opinion of a child's weight also contributes to low self-esteem.

Obese Chinese Primary-School Students and Low Self-Esteem: A Cross-Sectional Study

Science.gov (United States)

Xue-Yan, Zhang; Dong-Mei, Li; Dan-Dan, Xu; Le-Shan, Zhou

2016-01-01

Objectives The aim of this study was to examine several factors related to low self-esteem among obese Chinese primary-school students. Methods A cross-sectional study was conducted between June 2009 and June 2010. A total of 1,410 primary-school students (China grades 4 - 6) in Changsha city were divided into normal weight (n = 1,084), overweight (n = 211), and obese groups (n = 115) according to world health organization (WHO) growth standards for body mass index (BMI). The students were assessed using the self-esteem scale (SES) and a general situation questionnaire. Caregivers completed questionnaires about their child’s weight status. Self-esteem levels were explored; any factors related to low self-esteem were analyzed using logistic regression analysis. Results The average self-esteem score among overweight or obese primary-school students was found to be lower than that of normal-weight students. The proportion of students with low self-esteem in the obese group was more than that in the normal-weight and overweight groups. Multiple logistic regression analysis showed that obesity status (odds ratio [OR], 3.74; 95% confidence interval [CI], 2.25 - 6.22), overweight status (OR, 2.60; 95% CI, 1.71 - 3.95), obesity considered by children’s grandparents (OR, 1.76; 95% CI, 1.05 - 2.96), dissatisfaction with height (OR, 1.55; 95% CI, 1.11 - 2.18), and dissatisfaction with weight (OR, 1.45; 95% CI, 1.05 - 2.01) were the risk factors for low self-esteem for primary-school students, while satisfaction with academic performance was a protective factor (OR, 0.22; 95% CI, 0.07 - 0.71). Conclusions For Chinese primary-school students, low self-esteem is associated with higher weight status and self-perceived body shape and academic performance. In addition, grandparental opinion of a child’s weight also contributes to low self-esteem. PMID:27713806

Thermal equilibrium defects in anthracene probed by positron annihilation

International Nuclear Information System (INIS)

Uedono, Akira; Tanigawa, Shoichiro; Tachibana, Masaru; Shimizu, Mikio; Satoh, Masaaki; Kojima, Kenichi; Ishibashi, Shoji; Kawano, Takao.

1996-01-01

Defects in anthracene were investigated by the positron annihilation technique. Doppler broadening profiles of the annihilation radiation and lifetime spectra of positrons were measured in the temperature range between 305 K and 516 K. The lifetime of positrons annihilated from the delocalized state was determined to be 0.306 ns around room temperature. Below the melting point, the observed temperature dependence of the line shape parameter S was explained assuming the formation energy of thermal equilibrium defects was 1 eV. Above the melting point, the pick-off annihilation of ortho-positronium in open spaces was observed, where the size of these spaces was estimated to be 0.2 nm 3 . The annihilation of positrons from the self-trapped state was also discussed. (author)

Thermal equilibrium defects in anthracene probed by positron annihilation

Energy Technology Data Exchange (ETDEWEB)

Uedono, Akira; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Tachibana, Masaru; Shimizu, Mikio; Satoh, Masaaki; Kojima, Kenichi; Ishibashi, Shoji; Kawano, Takao

1996-06-01

Defects in anthracene were investigated by the positron annihilation technique. Doppler broadening profiles of the annihilation radiation and lifetime spectra of positrons were measured in the temperature range between 305 K and 516 K. The lifetime of positrons annihilated from the delocalized state was determined to be 0.306 ns around room temperature. Below the melting point, the observed temperature dependence of the line shape parameter S was explained assuming the formation energy of thermal equilibrium defects was 1 eV. Above the melting point, the pick-off annihilation of ortho-positronium in open spaces was observed, where the size of these spaces was estimated to be 0.2 nm{sup 3}. The annihilation of positrons from the self-trapped state was also discussed. (author)

Estimation of dislocation concentration in plastically deformed silver by positron annihilation

International Nuclear Information System (INIS)

ABdel-Rahman, M.A.; Badawi, E.A.; Abdel-Raheem, S.H.

1996-01-01

Positron annihilation mean lifetime measurements were performed on 7 different specimens of silver plastically deformed at room temperature (up to 56%). The positron mean lifetime exhibits a saturation for deformations larger than 14% thickness reduction. The fitted lifetime varies from (135.9+2 ps) for annealed silver to (207+ 2 ps) for the dislocation saturated value. Trapping cross-section and trapping efficiency were calculated. Dislocation concentration at saturation has been estimated. 3 figs

Estimation of dislocation concentration in plastically deformed silver by positron annihilation

Energy Technology Data Exchange (ETDEWEB)

ABdel-Rahman, M A; Badawi, E A; Abdel-Raheem, S H [Physics Dept., Faculty of Science, El-Minia University, El-Minia (Egypt)

1997-12-31

Positron annihilation mean lifetime measurements were performed on 7 different specimens of silver plastically deformed at room temperature (up to 56%). The positron mean lifetime exhibits a saturation for deformations larger than 14% thickness reduction. The fitted lifetime varies from (135.9+2 ps) for annealed silver to (207+ 2 ps) for the dislocation saturated value. Trapping cross-section and trapping efficiency were calculated. Dislocation concentration at saturation has been estimated. 3 figs.

Self-care agency in systemic lupus erythematosus and its associated factors: a cross-sectional study.

Science.gov (United States)

Yang, Hui; Xie, Xia; Song, Yuqing; Nie, Anliu; Chen, Hong

2018-01-01

The aim of this study was to estimate the level of self-care agency and explore its associated factors in patients with systemic lupus erythematosus (SLE). In this cross-sectional study, all patients were from a tertiary general hospital between July and October 2016 in Southwest China. The self-care agency was assessed using the Exercise of Self-care Agency Scale. Other variables were measured by the Visual Analog Scale, Systemic Lupus Erythematosus Disease Activity Index 2000, the physical component summary, and mental component summary of the 36-item Short Form Health Survey. Multivariate regression analysis was performed to explore the associated factors of self-care agency. A total of 123 patients were recruited. The mean score of Exercise of Self-care Agency Scale was 86.29. In univariate analysis, self-care agency of patients differed in regard to gender, work status, educational level, household income monthly per capita, and disease activity ( P agency ( P agency. Patients with SLE had a middle level of self-care agency, suggesting that there is still much scope for improvement. The lower level of self-care agency was associated with male gender, lower educational level, lower household income monthly per capita, and worse mental health. Therefore, health care providers should develop targeted and comprehensive interventions to enhance self-care agency in patients with SLE.

How do people respond to self-test results? A cross-sectional survey

Directory of Open Access Journals (Sweden)

de Vries Nanne K

2010-10-01

Full Text Available Abstract Background Self-tests, tests on medical conditions that can be performed by consumers without consulting a doctor first, are frequently used. Nevertheless, there are concerns about the safety of self-testing, as it may delay diagnosis and appropriate treatment in the case of inappropriate use of the test, or false-negative results. It is unclear whether self-tests stimulate appropriate follow-up behaviour. Our aim was to examine the frequency of self-test use, consumers' response to self-test results in terms of their confidence in the result, reassurance by the test result, and follow-up behaviour. Methods A two step cross-sectional survey was designed. A random sample of 6700 Internet users in an existing Internet panel received an online questionnaire on the use of self-tests. Self-tests were defined as tests on body materials, initiated by consumers with the aim to diagnose a disease or risk factor. A second questionnaire on consumers' response to self-test results was sent to the respondents that were identified as a self-tester in the first questionnaire (n = 703. Results 18.1% (799/4416 of the respondents had ever performed a self-test, the most frequently used tests being those for diabetes (5.3%, kidney disease (4.9%, cholesterol (4.5%, urinary tract infection (1.9% and HIV/AIDS and Chlamydia (both 1.6%. A total of 78.1% of the testers with a normal test result and 81.4% of those with an abnormal result reported confidence in this result. Almost all (95.6% of the testers with a normal result felt reassured. After a normal result, 78.1% did not take any further action and 5.8% consulted a doctor. The corresponding figures after an abnormal test result were 9.3% and 72.2%, respectively. Conclusions Respondents who had performed a self-test seemed to base their follow-up behaviour on the result of the test. They had confidence in the test result, and were often reassured by a normal result. After an abnormal result, most self

Invariant cross sections for inclusive reactions anti pp→π++X and anti pp→p+X at 22.4 GeV/c

International Nuclear Information System (INIS)

Boos, E.G.; Temiraliev, T.; Samojlov, V.V.

1977-01-01

Invariant inclusive cross sections for π + mesons and protons from antipp reactions at 22.4 GeV/c are presented. The average multiplicity for production of π + mesons is 1.92+-0.02 and for protons 0.41+-0.02. Annihilation spectra have been approximated by using the difference between antipp and pp data. The resulting distributions have similar gross features as the total antipp data. (author)

Vector dark matter annihilation with internal bremsstrahlung

Energy Technology Data Exchange (ETDEWEB)

Bambhaniya, Gulab, E-mail: gulab@prl.res.in [Physical Research Laboratory, Ahmedabad 380009 (India); Kumar, Jason, E-mail: jkumar@hawaii.edu [Department of Physics & Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Marfatia, Danny, E-mail: dmarf8@hawaii.edu [Department of Physics & Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Nayak, Alekha C., E-mail: acnayak@iitk.ac.in [Department of Physics, Indian Institute of Technology, Kanpur 208016 (India); Tomar, Gaurav, E-mail: tomar@prl.res.in [Physical Research Laboratory, Ahmedabad 380009 (India)

2017-03-10

We consider scenarios in which the annihilation of self-conjugate spin-1 dark matter to a Standard Model fermion–antifermion final state is chirality suppressed, but where this suppression can be lifted by the emission of an additional photon via internal bremsstrahlung. We find that this scenario can only arise if the initial dark matter state is polarized, which can occur in the context of self-interacting dark matter. In particular, this is possible if the dark matter pair forms a bound state that decays to its ground state before the constituents annihilate. We show that the shape of the resulting photon spectrum is the same as for self-conjugate spin-0 and spin-1/2 dark matter, but the normalization is less heavily suppressed in the limit of heavy mediators.

Two-photon annihilation into octet meson pairs. Symmetry relations in the handbag approach

International Nuclear Information System (INIS)

Diehl, M.; Kroll, P.; Regensburg Univ.

2009-11-01

We explore the implications of SU(3) flavor symmetry in the soft handbag mechanism for two-photon annihilation into pairs of pseudoscalar octet mesons. In this approach we obtain a good description of the experimental results for all measured channels at high energy, with two complex form factors adjusted to the data. We also predict the cross section for γγ→ηη. (orig.)

Measure of total nuclear absorption cross sections of photons in the Δ (1232) range. Studied nucleus 12C and 208Pb

International Nuclear Information System (INIS)

Ghedira, Lotfi

1984-01-01

We present a new determination of the nuclear total photoabsorption cross section, on carbon and lead in the Δ 33 resonance region: 133 MeV ≤ E γ ≤ 531 MeV. The principle of the experimental method is the measurement of the hadronic products emitted during the absorption process. We used the Saclay tagged photon beam obtained by flight annihilation of positrons. The reaction target was placed inside a cylindrical Nal scintillator, covering 93 pc of 4π. A set of plastic scintillators covered the inside of the detector in order to determine the charge multiplicity of the hadronic events. The very large efficiency of this detector allowed the detection of 70 to 80 pc of the total number of hadronic events, so that the uncertainties induced by the extrapolation of the undetected part of the cross section are small. The total hadronic cross section was found to be close to 400 μb/ nucleon at the maximum for both C and Pb. In addition to the total cross section we give values for a few partial cross sections. Previous experimental work as well as theoretical predictions are compared to our results. (author) [fr

A study of the effect of intermediate structure in the fission cross section of 239Pu on self-shielding factors

International Nuclear Information System (INIS)

Ganesan, S.

1978-01-01

A set of energy dependent fission widths of 1 + spin state corresponding to the recommended fission cross sections of Sowerby et al is evaluated by adjustment in the energy region 600 ev to 25 Kev. Corresponding to these mean fission widths of 1 + spin state, the intermediate resonance parameters based on Weigmann's formulation of Struitinsky's double humped fission barrier model are then obtained. Pseudorandom resonances are generated with and without the intermediate structure in the mean fission but leading to the same value of infinite dilution fission cross section. The effect of the intermediate structure on the self shielding factors was then investigated. (author)

Experimental study of the self-evaporation of an adiabatic upward flow of water in a duct of uniform cross section

International Nuclear Information System (INIS)

Barois, Guy

1969-01-01

This research thesis aims at being a contribution to a better knowledge of the expansion process in a flow, by studying the formation of vapour in an upward adiabatic vertical flow. This self-evaporation occurs in a duct with a large cross section (10 x 10 cm) in order to make neglectable pressure losses due to friction on the wall with respect to other pressure losses. After a presentation of the characteristics of the experimental installation, the author describes the flow, outlines the influence of dissolved air on vapour bubble nucleation. He describes the method used to measure the difference between the liquid temperature and that it would have had in thermal equilibrium under a vapour pressure equal to the cross section static pressure. Different theoretical analytical studies proposed by other authors are presented, and the author proposes a model for the calculation of pressure loss associated with this self-evaporation [fr

Verification of the accuracy of Doppler broadened, self-shielded multigroup cross sections for fast power reactor applications

International Nuclear Information System (INIS)

Ganesan, S.; Gopalakrishnan, V.; Ramanadhan, M.M.; Cullen, D.E.

1988-01-01

Verification results for Doppler broadening and self-shielding are presented. One of the important results presented is that the original SIGMA1 method of numerical Doppler broadening has now been demonstrated to be inaccurate and not capable of producing results to within required accuracies. Fortunately, due to this study, the SIGMA1 method has been significantly improved and the new SIGMA1 is now capable of producing results to within required accuracies. Although this paper presents results based upon using only one code system, it is important to realize that the original SIGMA1 method is presently used in many cross-section processing code systems; the results of this paper indicate that unless these other code systems are updated to include the new SIGMA1 method, the results produced by these code systems could be very inaccurate. The objectives of the IAEA nuclear data processing code verification project are reviewed as well as the requirements for the accuracy of calculation of Doppler coefficients and the present status of these calculations. The initial results of Doppler broadening and self-shielding calculations are presented and the inconsistency of the results which led to the discovery of errors in the original SIGMA1 method of Doppler broadening are pointed out. Analysis of the errors found and improvements in the SIGMA1 method are presented. Improved results are presented in order to demonstrate that the new SIGMA1 method can produce results within required accuracies. Guidelines are presented to limit the uncertainty introduced due to cross-section processing in order to balance available computer resources to accuracy requirements. Finally cross-section processing code users are invited to participate in the IAEA processing code verification project in order to verify the accuracy of their calculated results. (author)

Annihilation vs. decay: constraining dark matter properties from a gamma-ray detection

International Nuclear Information System (INIS)

Palomares-Ruiz, Sergio; Siegal-Gaskins, Jennifer M.

2010-01-01

Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is also the possibility of unstable (but long-lived) dark matter, produced thermally or otherwise. We propose a strategy to distinguish between dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way dwarf spheroidal galaxies with gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both. In addition, once the type of signal is established, we show how these measurements could help to extract information about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay channels, and the presence of substructure. Although an application of the approach presented here would likely be feasible with current experiments only for very optimistic dark matter scenarios, the improved sensitivity of upcoming experiments could enable this technique to be used to study a wider range of dark matter models

Annihilation vs. decay: constraining dark matter properties from a gamma-ray detection

Energy Technology Data Exchange (ETDEWEB)

Palomares-Ruiz, Sergio [Centro de Física Teórica de Partículas, Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Siegal-Gaskins, Jennifer M., E-mail: sergio.palomares.ruiz@ist.utl.pt, E-mail: jsg@mps.ohio-state.edu [Center for Cosmology and AstroParticle Physics, The Ohio State University, 191 W. Woodruff Ave., Columbus OH 43210 (United States)

2010-07-01

Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is also the possibility of unstable (but long-lived) dark matter, produced thermally or otherwise. We propose a strategy to distinguish between dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way dwarf spheroidal galaxies with gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both. In addition, once the type of signal is established, we show how these measurements could help to extract information about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay channels, and the presence of substructure. Although an application of the approach presented here would likely be feasible with current experiments only for very optimistic dark matter scenarios, the improved sensitivity of upcoming experiments could enable this technique to be used to study a wider range of dark matter models.

Total and inclusive hadron production by e+e- annihilation at √S = 5.2, 6.5 and 29.0 GeV

International Nuclear Information System (INIS)

Patrick, J.F.

1982-07-01

Measurements are presented of R, the ratio of the total hadronic cross section to the cross section for mu pair production, and of the inclusive charged particle momentum distribution so sigma/dx for e + e - annihilation at center of mass energies of 5.2, 6.5, and 29.0 GeV. The ratio R is found to be approximately 3.9, consistent with quark-parton model expectations, at each of the three energies with an estimated systematic uncertainty of 6%. The inclusive cross sections show significant deviation from the scaling behavior predicted by the quark-parton model

Illness perception, diabetes knowledge and self-care practices among type-2 diabetes patients: a cross-sectional study.

Science.gov (United States)

Kugbey, Nuworza; Oppong Asante, Kwaku; Adulai, Korkor

2017-08-10

Self-care practices among persons living with type-2 diabetes are very crucial in diabetes manages as poor self-care results in complications. However, little research exists within the Ghanaian context. This study examined whether type-2 diabetes patients' illness perception and diabetes knowledge significantly predict diabetes self-care practices. A cross-sectional survey design was employed and a total of 160 participants (45 males and 115 females) were sampled from a general hospital in Accra. A self-administered questionnaire measuring illness perception, diabetes knowledge and diabetes self-care practices as well as demographic checklist were used collect data. Results showed that illness perception and diabetes knowledge significantly predicted overall diabetes self-care practices. Analysis of domain specific self-care practices showed that patients' diet was significantly predicted by illness perception and diabetes knowledge. Exercise was significantly predicted by only illness perception while blood sugar testing and diabetes foot-care were significantly predicted by diabetes knowledge. Cognitive and emotional representation of diabetes and diabetes knowledge are key determinants of patients' diabetes self-care practices. It is therefore important that appropriate psychosocial interventions are developed to help patients' adherence to recommended self-care practices.

anti p-3He reaction cross section at 200 MeV/c

International Nuclear Information System (INIS)

Balestra, F.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Ferrero, L.; Grasso, A.; Panzieri, D.; Piragino, G.; Tosello, F.; Barbieri, R.; Bendiscioli, G.; Rotondi, A.; Salvini, P.; Venaglioni, A.; Zenoni, A.; Batusov, Yu.A.; Falomkin, I.V.; Pontecorvo, G.B.; Sapozhnikov, M.G.; Tretyak, V.I.; Breivik, F.O.; Jacobsen, T.; Soerensen, S.O.

1988-01-01

Inelastic anti p- 3 He events at 192.8 MeV/c are detected with a self-shunted streamer chamber. The measured reaction cross section is 392±23.8 mb. This result is briefly discussed and compared with other reaction cross sections for low-energy anti p with light nuclei. (orig.)

The inclusive cross section of charged hadrons in 3-jet events at √s = 29 GeV

International Nuclear Information System (INIS)

Rouse, F.R.

1987-10-01

We examine the cross section for the production of charged hadrons in 3-jet events produced from e/sup /plus/e/sup /minus// annihilation at 29 GeV center of mass energy. The data was taken at the Pep-4Time Projection Chamber between 1983-1984. In particular we are interested in the production of hadrons by the particle which mediates the strong interaction, the gluon. We find that the number of protons produced by the fragmentation of the gluon is at variance with the LUND model of fragmentation. 85 refs., 72 figs., 29 tabs

The Influence of Health Literacy and Depression on Diabetes Self-Management: A Cross-Sectional Study

Directory of Open Access Journals (Sweden)

D. Maneze

2016-01-01

Full Text Available Despite an increasing focus on health literacy in the clinical setting and in the literature, there is still ongoing debate about its influence on diabetes self-management. The aim of the study was to examine the relationships of sociodemographic, clinical, and psychological factors on health literacy and diabetes self-management. A cross-sectional survey was undertaken on 224 patients with type 2 diabetes at two diabetes centres in Sydney, Australia. Findings showed that people with low health literacy were more likely to (a have lower educational attainment; (b be migrants; and (c have depressed mood. Unexpectedly, those who met HbA1c threshold of good glucose control were more likely to have low health literacy. Predictors of low diabetes self-management included (a younger age group (AOR: 2.58, 95% CI: 1.24–4.64; (b having postsecondary education (AOR: 2.30, 95% CI: 1.05–5.01; (c low knowledge of diabetes management (AOR: 2.29, 95% CI: 1.25–4.20; and (d having depressed mood (AOR: 2.30, 95% CI: 1.30–4.06. The finding that depressed mood predicted both low health literacy and low diabetes self-management stresses the importance of screening for depression. Increasing people’s understanding of diabetes self-management and supporting those with depression are crucial to enhance participation in diabetes self-management.

Transverse momentum distribution of the three-jet event cross section in e+e--annihilation

International Nuclear Information System (INIS)

Shakhnazaryan, Yu.G.

1984-01-01

The differential in the variables T (momentum of the most energetic parton) and x sub(perpendicular) (transverse momentum with respect to the axis T vector momentum of each of the two remaining partons) cross section of the three-jet process e + e - → q anti qg is calculated in the first order of QCD. The transverse momentum distribution is also found that is integrated over all T in the range of values T admissible for the three-jet event. The contribution in the mentioned distributions of the three regions, differing by the relative value of the gluon momentum, is investigated with a view to reveal the possibility of identification of quark-antiquark and gluon jets

Role of dystrophic epidermolysis bullosa in anxiety, depression and self-esteem: A controlled cross-sectional study.

Science.gov (United States)

Fortuna, Giulio; Aria, Massimo; Cepeda-Valdes, Rodrigo; Garcia-Garcia, Sandra Cecilia; Moreno Trevino, Maria Guadalupe; Salas-Alanís, Julio Cesar

2016-01-01

The psychological aspect in patients with dystrophic epidermolysis bullosa (DEB) is poorly documented. We sought to determine the role of DEB in anxiety, depression and self-esteem. We conducted a cross-sectional study, collecting data from 27 DEB patients and 26 healthy individuals. DEB patients and healthy controls completed three different psychometric scales for anxiety and depression and one scale for self-esteem. DEB patients and healthy controls were homogeneous for age and sex (P > 0.05), but not for employment, marital status and economic level (P depression (P = 0.037) and slightly significant for Zung Scale for anxiety (P = 0.048) with no difference between DEB patients with dominant versus recessive form in all scales (P > 0.05). Among DEB patients, only employment showed a significant difference in all scales (P depression, whereas self-esteem seemed to be affected by marriage (P = 0.04) and education (P = 0.016). DEB patients apparently are not more anxious and/or depressed and do not have less self-esteem than healthy individuals. © 2015 Japanese Dermatological Association.

Factors associated with self-esteem in persons with morbid obesity and in persons with chronic obstructive pulmonary disease: a cross-sectional study.

Science.gov (United States)

Bonsaksen, Tore; Fagermoen, May Solveig; Lerdal, Anners

2015-01-01

Living with chronic illnesses can be stressful and may negatively impact persons' self-esteem. Personal factors, like self-efficacy and illness perceptions, and also factors related to the environment, activity, and participation may be associated with self-esteem in chronic illness populations. This cross-sectional comparative study explored sociodemographic variables, work, physical activity, illness perceptions, and general self-efficacy in relation to self-esteem in persons with morbid obesity and in persons with chronic obstructive pulmonary disease (COPD). The study had a cross-sectional design. A total of 223 eligible participants were recruited from patient education courses, and data were collected at baseline. Self-esteem was measured with The Rosenberg self-esteem scale; the general self-efficacy scale was used to measure self-efficacy, and brief illness perception questionnaire was also used. This is an instrument assessing cognitions about the illness and emotional responses towards it. Multivariate linear regression was used in the statistical analyses. In obese participants (n = 134), higher self-esteem was associated with lower emotional response, a shorter timeline, and higher general self-efficacy. In COPD participants (n = 89), higher self-esteem was associated with higher general self-efficacy. The independent variables accounted for 42.9% (morbid obesity) and 49.4% (COPD) of the self-esteem variance. In participants in both illness groups, higher self-efficacy was associated with increased self-esteem. A shorter timeline and lower emotional response to illness was related to higher self-esteem only for the obese participants. The results indicate that believing in one's capacity to cope with everyday challenges is important for self-esteem in persons with morbid obesity and in persons with COPD, whereas illness perceptions related to the duration of illness and the coping with emotions also is important for self-esteem in persons with morbid

Heavy lepton production in e+e- annihilation

International Nuclear Information System (INIS)

Kawamoto, Noboru

1976-01-01

We first enumerate several global properties of e + e - annihilation, which were left untouched in previous studies, as evidences of a heavy lepton with the mass of 1.8 GeV. As for the charged energy fraction in e + e - annihilation, we note that the effect of heavy lepton productions superimposed on the linearly decreasing background parametrized as r sub(h)=-0.014√s+0.632 can give a satisfactory fit to the data up to √s -- 8 GeV (where √s is the total c.m. energy). In this case, the charged energy fraction at PEP and PETRA energies is expected to come far below the naive application of the Llewellyn-Smith-Pais lower bound. We also compare the heavy lepton interpretation of the eμ events with other interpretations, and we argue that the 1.8 GeV heavy lepton gives the most plausible interpretation. Finally we discuss the observed eμ cross section and momentum distributions in terms of this heavy lepton with a general structure of the weak current and with an arbitrary mass for the associated neutrino. (auth.)

Standard cross-section data

International Nuclear Information System (INIS)

Carlson, A.D.

1984-01-01

The accuracy of neutron cross-section measurement is limited by the uncertainty in the standard cross-section and the errors associated with using it. Any improvement in the standard immediately improves all cross-section measurements which have been made relative to that standard. Light element, capture and fission standards are discussed. (U.K.)

Measurement of proton inelastic scattering cross sections on fluorine

Energy Technology Data Exchange (ETDEWEB)

Chiari, M., E-mail: chiari@fi.infn.it [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy); Caciolli, A. [Department of Physics and Astronomy, University of Padua and INFN Padua, Padova (Italy); Calzolai, G. [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy); Climent-Font, A. [CMAM, Universidad Autonoma de Madrid, Madrid (Spain); Lucarelli, F.; Nava, S. [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy)

2016-10-01

Differential cross-sections for proton inelastic scattering on fluorine, {sup 19}F(p,p’){sup 19}F, from the first five excited levels of {sup 19}F at 110, 197, 1346, 1459 and 1554 keV were measured for beam energies from 3 to 7 MeV at a scattering angle of 150° using a LiF thin target (50 μg/cm{sup 2}) evaporated on a self-supporting C thin film (30 μg/cm{sup 2}). Absolute differential cross-sections were calculated with a method not dependent on the absolute values of collected beam charge and detector solid angle. The validity of the measured inelastic scattering cross sections was then tested by successfully reproducing EBS spectra collected from a thick Teflon (CF{sub 2}) target. As a practical application of these measured inelastic scattering cross sections in elastic backscattering spectroscopy (EBS), the feasibility of quantitative light element (C, N and O) analysis in aerosol particulate matter samples collected on Teflon by EBS measurements and spectra simulation is demonstrated.

Neutron-photon multigroup cross sections for neutron energies up to 400 MeV: HILO86R

International Nuclear Information System (INIS)

Kotegawa, Hiroshi; Nakane, Yoshihiro; Hasegawa, Akira; Tanaka, Shun-ichi

1993-02-01

A macroscopic multigroup cross section library of 66 neutron and 22 photon groups for neutron energies up to 400 MeV: HILO86R is prepared for 10 typical shielding materials; water, concrete, iron, air, graphite, polyethylene, heavy concrete, lead, aluminum and soil. The library is a revision of the DLC-119/HILO86, in which only the cross sections below 19.6 MeV have been exchanged with a group cross section processed from the JENDL-3 microscopic cross section library. In the HILO86R library, self shielding factors are used to produce effective cross sections for neutrons less than 19.6 MeV considering rather coarse energy meshes. Energy spectra and dose attenuation in water, concrete and iron have been compared among the HILO, HILO86 and HILO86R libraries for different energy neutron sources. Significant discrepancy has been observed in the energy spectra less than a couple of MeV energy in iron among the libraries, resulting large difference in the dose attenuation. The difference was attributed to the effect of self-shielding factor, namely to the difference between infinite dilution and effective cross sections. Even for 400 MeV neutron source the influence of the self-shielding factor is significant, nevertheless only the cross sections below 19.6 MeV are exchanged. (author)

Measurements of cross section of e+e−→pp¯π0 at center-of-mass energies between 4.008 and 4.600 GeV

Directory of Open Access Journals (Sweden)

M. Ablikim

2017-08-01

Full Text Available Based on e+e− annihilation data samples collected with the BESIII detector at the BEPCII collider at 13 center-of-mass energies from 4.008 to 4.600 GeV, measurements of the Born cross section of e+e−→pp¯π0 are performed. No significant resonant structure is observed in the measured energy dependence of the cross section. The upper limit on the Born cross section of e+e−→Y(4260→pp¯π0 at the 90% C.L. is determined to be 0.01 pb. The upper limit on the ratio of the branching fractions B(Y(4260→pp¯π0B(Y(4260→π+π−J/ψ at the 90% C.L. is determined to be 0.02%.

Comparison of π±, K± and p, anti p production in the central rapidity region in hadron-hadron collisions and in e+e- annihilation

International Nuclear Information System (INIS)

Aihara, H.; Enomoto, R.; Fujii, T.; Kamae, T.; Takahashi, T.; Toge, N.; Alston-Garnjost, M.; Avery, R.E.; Barbaro-Galtieri, A.; Barnes, A.V.; Bolognese, T.S.; Bross, A.D.; Clark, A.R.; Cowan, G.D.; Dahl, O.L.; Derby, K.A.; Eastman, J.J.; Eberhard, P.H.; Edberg, T.K.; Gary, J.W.; Hofmann, W.; Huth, J.E.; Kaye, H.S.; Kenney, R.W.; Kerth, L.T.; Loken, S.C.; Lynch, G.R.; Madaras, R.J.; Marx, J.N.; Mathis, L.G.; Moses, W.; Nygren, D.R.; Oddone, P.J.; Pripstein, M.; Ronan, M.T.; Ross, R.R.; Rouse, F.R.; Shapiro, G.; Shapiro, M.D.; Stevenson, M.L.; Van Tyen, R.; Wagner, W.; Wang, E.M.; Wenzel, W.A.; Wolf, Z.R.; Yamamoto, H.; Barker, A.R.; Bauer, D.A.; Caldwell, D.O.; Lu, A.; Schwitkis, K.A.; Wang, Y.X.; Yellin, S.J.; Barnett, B.A.; Crane, D.A.; Hylen, J.; Lu, X.Q.; Matthews, J.A.J.; Zhang, W.M.; Bengtsson, H.U.; Buchanan, C.D.; Koda, R.I.; Park, D.A.; Slater, W.E.; Steinman, J.S.; Stork, D.H.; Strauss, M.G.; Van Daalen Wetters, R.R.; Wayne, M.R.; Bintinger, D.L.; Kees, K.H.; Masek, G.E.; Miller, E.S.; Thompson, J.R.; Vernon, W.; White, J.T.; Bobbink, G.J.; Buijs, A.; Erne, F.C.; Linde, F.L.; Paar, H.P.; Sens, J.C.; Uitert, B. van; Eisner, A.M.; Magnuson, B.D.; Sullivan, M.K.; Hauptman, J.M.; Park, S.K.; Ko, W.; Lander, R.L.; Maeshima, K.; McNeil, R.R.; Pellet, D.E.; Smith, J.R.; Williams, M.S.C.; Zeitlin, C.; Kofler, R.R.; Maxfield, S.J.; Toutounchi, S.; Nemethy, P.

1987-01-01

We compare the p T dependence of pion, kaon and proton production cross sections in the central rapidity region in e + e - annihilation events and in proton-proton collisions at ISR energies. We find similarities both in the p T dependence of cross sections and in the particle composition as a function of p T , in agreement with the hypothesis of a universal mechanism of particle production. (orig.)

The effects of workplace flexibility on health behaviors: a cross-sectional and longitudinal analysis.

Science.gov (United States)

Grzywacz, Joseph G; Casey, Patrick R; Jones, Fiona A

2007-12-01

To examine the cross-sectional and longitudinal associations between workplace flexibility and health behaviors, and estimate the potential importance of flexibility for effective worksite health promotion programs. Cross-sectional and longitudinal health risk appraisal data were obtained from US based employees of a multinational pharmaceutical company (n = 3193). Examined health behaviors were hours of sleep, physical activity frequency, health education seminar attendance, frequency of practicing personal resilience techniques, and self-appraised lifestyle. Self-reported flexibility in the workplace was the primary independent variable. Each health behavior, except regular attendance in health education seminars, was positively related to perceived flexibility in cross-sectional analyses. Sleep and self-appraised lifestyle were significantly related to changes in perceived flexibility over time. Workplace flexibility may contribute to positive lifestyle behaviors, and may play an important role in effective worksite health promotion programs.

Dark matter annihilation into four-body final states and implications for the AMS antiproton excess

Science.gov (United States)

Clark, Steven J.; Dutta, Bhaskar; Strigari, Louis E.

2018-01-01

We consider dark matter annihilation into a general set of final states of standard model particles, including two-body and four-body final states that result from the decay of intermediate states. For dark matter masses ˜10 - 105 GeV , we use updated data from Planck and from high gamma-ray experiments such as Fermi-LAT, MAGIC, and VERITAS to constrain the annihilation cross section for each final state. The Planck constraints are the most stringent over the entire mass range for annihilation into light leptons, and the Fermi-LAT constraints are the most stringent for four-body final states up to masses ˜104 GeV . We consider these constraints in light of the recent AMS antiproton results, and show that for light mediators it is possible to explain the AMS data with dark matter, and remain consistent with Fermi-LAT Inner Galaxy measurements, for mχ˜60 - 100 GeV mass dark matter and mediator masses mϕ/mχ≲1 .

Inclusive charmonium production via double cc-bar in e+e- annihilation

International Nuclear Information System (INIS)

Liu Kuiyong; He Zhiguo; Chao Kuangta

2004-01-01

Motivated by the recent observation of double-charm quark pair production by the Belle Collaboration, we calculate the complete O(α s 2 ) inclusive production cross sections for η c , J/ψ, and χ cJ (J=0,1,2) plus cc-bar in e + e - annihilation through a virtual photon. We consider both color-singlet and color-octet contributions, and give the analytical expressions for these cross sections. The complete color-singlet calculations are compared with the approximate fragmentation calculations as functions of the center-of-mass energy √(s). We find that most of the fragmentation results substantially overestimate the cross sections (e.g., by a factor of ∼4 for χ c1 and χ c2 ) at the Belle and BaBar energy √(s)=10.6 GeV. The fragmentation results become a good approximation only when √(s) is higher than about 100 GeV. We further calculate the color-octet contributions to these cross sections with analytical expressions. We find that while the color-octet contribution to J/ψ inclusive production via double charm is negligible (only about 7%), the color-octet contributions to χ c1 and χ c2 can be very significant

Anisotropy of the cosmic gamma-ray background from dark matter annihilation

International Nuclear Information System (INIS)

Ando, Shin'ichiro; Komatsu, Eiichiro

2006-01-01

High-energy photons from pair annihilation of dark matter particles contribute to the cosmic gamma-ray background (CGB) observed in a wide energy range. Since dark matter particles are weakly interacting, annihilation can happen only in high density regions such as dark matter halos. The precise shape of the energy spectrum of CGB depends on the nature of dark matter particles--their mass and annihilation cross section, as well as the cosmological evolution of dark matter halos. In order to discriminate between the signals from dark matter annihilation and other astrophysical sources, however, the information from the energy spectrum of CGB may not be sufficient. We show that dark matter annihilation not only contributes to the mean CGB intensity, but also produces a characteristic anisotropy, which provides a powerful tool for testing the origins of the observed CGB. We develop the formalism based on a halo model approach to analytically calculate the three-dimensional power spectrum of dark matter clumping, which determines the power spectrum of annihilation signals. We show that the expected sensitivity of future gamma-ray detectors such as the Gamma Ray Large Area Space Telescope (GLAST) should allow us to measure the angular power spectrum of CGB anisotropy, if dark matter particles are supersymmetric neutralinos and they account for most of the observed mean intensity of CGB in GeV region. On the other hand, if dark matter has a relatively small mass, on the order of 20 MeV, and accounts for most of the CGB in MeV region, then the future Advanced Compton Telescope (ACT) should be able to measure the angular power spectrum in MeV region. As the intensity of photons from annihilation is proportional to the density squared, we show that the predicted shape of the angular power spectrum of gamma rays from dark matter annihilation is different from that due to other astrophysical sources such as blazars and supernovae, whose intensity is linearly proportional to

Limits on dark matter annihilation in the sun using the ANTARES neutrino telescope

Directory of Open Access Journals (Sweden)

S. Adrián-Martínez

2016-08-01

Full Text Available A search for muon neutrinos originating from dark matter annihilations in the Sun is performed using the data recorded by the ANTARES neutrino telescope from 2007 to 2012. In order to obtain the best possible sensitivities to dark matter signals, an optimisation of the event selection criteria is performed taking into account the background of atmospheric muons, atmospheric neutrinos and the energy spectra of the expected neutrino signals. No significant excess over the background is observed and 90% C.L. upper limits on the neutrino flux, the spin-dependent and spin-independent WIMP-nucleon cross-sections are derived for WIMP masses ranging from 50 GeV to 5 TeV for the annihilation channels WIMP+WIMP→bb¯,W+W− and τ+τ−.

Predictors of breast feeding self-efficacy among Chinese mothers: a cross-sectional questionnaire survey.

Science.gov (United States)

Zhu, Jiemin; Chan, Wai Chi Sally; Zhou, Xiuzhu; Ye, Benlan; He, Hong-Gu

2014-06-01

to examine breast feeding self-efficacy and identify its predictors among expectant Chinese mothers in the antenatal period. a cross-sectional descriptive questionnaire survey was conducted in the antenatal clinics of three university hospitals in China between September and December 2011. expectant mothers planning to breast feed, and who were at least 18 years of age, expecting a single, healthy, full-term baby, and competent in Mandarin (n=201). a socio-demographic data sheet, the Chinese version of the Breastfeeding Self-Efficacy Scale, and the Perceived Social Support Scale. the expectant Chinese mothers reported moderate levels of breast feeding self-efficacy. Expectant mothers who had had previous experience in breast feeding, who had watched other mothers breast feed their infants, or who had made the decision to breast feed earlier reported higher breast feeding self-efficacy. Expectant mothers' perceived social support, perceived attitude of significant others, including husband, mothers, and friends, towards breast feeding are correlated with breast feeding self-efficacy. The best-fit regression analysis revealed five variables that explained 34% of the variance in breast feeding self-efficacy in the antenatal period: perceived social support, previous experience of breast feeding, previous experience of watching others breast feed, timing of maternal decision to breast feed, and perceived husband's attitude towards breast feeding. this study highlighted the importance of improving Chinese mothers' breast feeding self-efficacy by considering the main predictors found in this study. health care professionals could develop strategies to promote breast feeding self-efficacy, such as providing opportunities for expectant mothers to learn from others' successful experience, adopt a family-centred approach in the provision of breast feeding education, provide breast feeding education at the beginning of pregnancy or even earlier, and rally comprehensive social

The Importance of the Maternal/Self-Role Satisfaction for Reducing Anxiety: A Cross-Sectional Survey of Japanese Mothers.

Science.gov (United States)

Iwasaki, Riho; Arimoto, Azusa; Naruse, Takashi; Nagata, Satoko; Murashima, Sachiyo

Women who rear children have two types of roles: the maternal role and the self-role. Previous studies have suggested that maternal role satisfaction is related to anxiety, but the importance of self-role satisfaction in promoting the health of mothers has received less attention. The changing roles of women in society, especially in urban areas, have altered mothers' views of child-rearing. Our primary focus was on the relationship between maternal/self-role satisfaction and anxiety in mothers. To examine this, we conducted a cross-sectional survey using self-administered questionnaires that were distributed in 2011 to 2,342 mothers attending the 18-month health checkup of their children, in 7 cities of the Tokyo metropolitan area. A total of 881 responded (effective response rate = 38.0%). Multiple regression analysis revealed that maternal role satisfaction and self-role satisfaction were both significantly and negatively associated with anxiety. Thus, self-role satisfaction should be considered alongside maternal role satisfaction in evaluating and reducing anxiety. Health care professionals in community settings should conduct comprehensive assessments of maternal role satisfaction and self-role satisfaction.

The 21 cm signal and the interplay between dark matter annihilations and astrophysical processes

Energy Technology Data Exchange (ETDEWEB)

Lopez-Honorez, Laura [Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Mena, Olga; Moliné, Ángeles; Palomares-Ruiz, Sergio [Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, E-46071 Valencia (Spain); Vincent, Aaron C., E-mail: llopezho@vub.ac.be, E-mail: omena@ific.uv.es, E-mail: maria.moline@ist.utl.pt, E-mail: sergio.Palomares.Ruiz@ific.uv.es, E-mail: aaron.vincent@durham.ac.uk [Institute for Particle Physics Phenomenology (IPPP), Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)

2016-08-01

Future dedicated radio interferometers, including HERA and SKA, are very promising tools that aim to study the epoch of reionization and beyond via measurements of the 21 cm signal from neutral hydrogen. Dark matter (DM) annihilations into charged particles change the thermal history of the Universe and, as a consequence, affect the 21 cm signal. Accurately predicting the effect of DM strongly relies on the modeling of annihilations inside halos. In this work, we use up-to-date computations of the energy deposition rates by the products from DM annihilations, a proper treatment of the contribution from DM annihilations in halos, as well as values of the annihilation cross section allowed by the most recent cosmological measurements from the Planck satellite. Given current uncertainties on the description of the astrophysical processes driving the epochs of reionization, X-ray heating and Lyman-α pumping, we find that disentangling DM signatures from purely astrophysical effects, related to early-time star formation processes or late-time galaxy X-ray emissions, will be a challenging task. We conclude that only annihilations of DM particles with masses of ∼100 MeV, could leave an unambiguous imprint on the 21 cm signal and, in particular, on the 21 cm power spectrum. This is in contrast to previous, more optimistic results in the literature, which have claimed that strong signatures might also be present even for much higher DM masses. Additional measurements of the 21 cm signal at different cosmic epochs will be crucial in order to break the strong parameter degeneracies between DM annihilations and astrophysical effects and undoubtedly single out a DM imprint for masses different from ∼100 MeV.

New SCALE-4 features related to cross-section processing

International Nuclear Information System (INIS)

Petrie, L.M.; Landers, N.F.; Greene, N.M.; Parks, C.V.

1991-01-01

The SCALE code system has a standardized scheme for processing problem-dependent cross section from problem-independent waste libraries. Some improvements and new capabilities in the processing scheme have been incorporated into the new Version 4 release of the SCALE system. The new features include the capability to consider annular cylindrical and spherical unit cells, and improved Dancoff factor formulation, and changes to the NITAWL-II module to perform resonance self-shielding with reference to infinite dilute values. A review of these major changes in the cross-section processing scheme for SCALE-4 is presented in this paper

Intensity-Frontier Antiproton Physics with The Antiproton Annihilation Spectrometer (TAPAS) at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Apollinari, Giorgio; /Fermilab; Asner, David M.; /PNL, Richland; Baldini, Wander; /INFN, Ferrara; Bartoszek, Larry; Broemmelsiek, Daniel R.; Brown, Charles N.; /Fermilab; Chakravorty, Alak; /St. Xavier U., Chicago; Colas, Paul; /Saclay; Derwent, Paul; /Fermilab; Drutskoy, Alexey; /Moscow, ITEP; Fortner, Michael; /Northern Illinois U. /Saclay /Indian Inst. Tech., Hyderabad

2011-11-01

The Fermilab Antiproton Source is the world's most intense source of antimatter. With the Tevatron program now behind us, this unique facility can help make the case for Fermilab's continued accelerator operations. The Antiproton Source can be used for unique, dedicated antimatter studies, including medium-energy {bar p}-annihilation experiments. We propose to assemble a powerful, yet cost-effective, solenoidal magnetic spectrometer for antiproton-annihilation events, and to use it at the Fermilab Antiproton Accumulator to measure the charm production cross section, study rare hyperon decays, search for hyperon CP asymmetry, precisely measure the properties of several charmonium and nearby states, and make the first measurements of the Drell-Yan continuum in medium-energy antiproton annihilation. Should the charm production cross section be as large as some have proposed, we will also be able to measure D{sup 0}-{bar D}{sup 0} mixing with high precision and discover (or sensitively limit) charm CP violation. The observation of charm or hyperon CP violation would be evidence for physics beyond the Standard Model, with possible implications for the origin of the baryon asymmetry of the universe - the question of what happened to all the antimatter that must have been produced in the Big Bang. The experiment will be carried out by an international collaboration and will require some four years of running time. As possibly the sole hadron experiment in progress at Fermilab during that time, it will play an important role in maintaining a broad particle physics program at Fermilab and in the U.S. It will thus help us to continue attracting creative and capable young people into science and technology, and introducing them to the important technologies of accelerators, detectors, and data acquisition and analysis - key roles in society that accelerator-based particle physics has historically played.

Explanation of the 511 keV line. Cascade annihilating dark matter with the {sup 8}Be anomaly

Energy Technology Data Exchange (ETDEWEB)

Jia, Lian-Bao [Southwest University of Science and Technology, School of Science, Mianyang (China)

2018-02-15

A possible dark matter (DM) explanation about the long-standing issue of the Galactic 511 keV line is explored in this paper. For DM cascade annihilations of concern, a DM pair π{sub d}{sup +}π{sub d}{sup -} annihilates into unstable π{sub d}{sup 0}π{sub d}{sup 0}, and π{sub d}{sup 0} decays into e{sup +}e{sup -} with new interactions suggested by the {sup 8}Be anomaly. Considering the constraints from the effective neutrino number N{sub eff} and the 511 keV gamma-ray emission, a range of DM is obtained, 11.6 annihilation cross section today is about 3.3 x 10{sup -29} cm{sup 3} s{sup -1}, which can give an explanation about the 511 keV line. The MeV scale DM may be searched by the DM-electron scattering, and the upper limit set by the CMB s-wave annihilation is derived in DM direct detections. (orig.)

Self-stigma and quality of life in patients with depressive disorder: a cross-sectional study.

Science.gov (United States)

Holubova, Michaela; Prasko, Jan; Ociskova, Marie; Marackova, Marketa; Grambal, Ales; Slepecky, Milos

2016-01-01

Self-stigma is a maladaptive psychosocial phenomenon that can affect many areas of patients' lives and have a negative impact on their quality of life (QoL). This study explored the association between self-stigma, QoL, demographic data, and the severity of symptoms in patients with depressive disorder. Patients who met the International Classification of Diseases, 10th revision, research criteria for depressive disorder were enrolled in this cross-sectional study. All outpatients completed the following measurements: the Quality of Life Enjoyment and Satisfaction Questionnaire, the Internalized Stigma of Mental Illness Scale, demographic questionnaire, and the objective and subjective Clinical Global Impression-Severity scales that measure the severity of disorder. A total of 81 depressive disorder patients (with persistent affective disorder - dysthymia, major depressive disorder, or recurrent depressive disorder) and 43 healthy controls participated in this study. Compared with the healthy control group, a lower QoL was observed in patients with depressive disorder. The level of self-stigma correlated positively with total symptom severity score and negatively with QoL. Multiple regression analysis revealed that the overall rating of objective symptom severity and score of self-stigma were significantly associated with QoL. This study suggests a lower QoL in patients with depressive disorder in comparison with healthy controls and a negative impact of self-stigma level on QoL in patients suffering from depressive disorders.

Cross sections for atmospheric corrections

International Nuclear Information System (INIS)

Meyer, J.P.; Casse, M.; Westergaard, N.

1975-01-01

A set of cross sections for spallation of relativistic nuclei is proposed based on (i) the best available proton cross sections, (ii) an extrapolation to heavier nuclei of the dependence on the number of nucleons lost of the 'target factor' observed for C 12 and O 16 by Lindstrom et al. (1975), in analogy with Rudstam's formalism, and (iii) on a normalization of all cross sections to the total cross sections for production of fragments with Asub(f) >= 6. The obtained cross sections for peripheral interactions are not inconsistent with simple geometrical considerations. (orig.) [de

What is the relationship between parental support, self-efficacy and physical activity in young students? A pilot cross-sectional study

Directory of Open Access Journals (Sweden)

Ruiz-Ariza Alberto

2017-01-01

Full Text Available This study examined the relationships between parental support for physical activity, weekly Physical Activity (PA practice frequency, and self-efficacy expectations to overcome barriers to participation. A total of 335 adolescents took part in this pilot cross-sectional study. The results show that boys and girls who attribute parents to a high level of instrumental support, modeling and behavioral limitation are allocated to higher number of days per week to perform the physical-sport activity during a minimum interval of sixty minutes and were more self-efficacious in their practice. Likewise, the frequency of practice of the activity and self-efficacy were higher in the case of boys.

Impact of SUSY-QCD corrections on neutralino-stop co-annihilation and the neutralino relic density

Energy Technology Data Exchange (ETDEWEB)

Harz, Julia [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Herrmann, Bjoern [Savoie Univ./CNRS, Annecy-le-Vieux (France). LAPTh; Klasen, Michael [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Kovarik, Karol [Karlsruher Institut fuer Technologie, Karlsruhe (Germany). Inst. fuer Theoretische Physik; Le Boulc' h, Quentin [Grenoble Univ./CNRS-IN2P3/INPG, Grenoble (France). Lab. de Physique Subatomique et de Cosmologie

2013-02-15

We have calculated the full O({alpha}{sub s}) supersymmetric QCD corrections to neutralino-stop coannihilation into electroweak vector and Higgs bosons within the Minimal Supersymmetric Standard Model (MSSM).We performed a parameter study within the phenomenological MSSM and demonstrated that the studied co-annihilation processes are phenomenologically relevant, especially in the context of a 126 GeV Higgs-like particle. By means of an example scenario we discuss the effect of the full next-to-leading order corrections on the co-annihilation cross section and show their impact on the predicted neutralino relic density. We demonstrate that the impact of these corrections on the cosmologically preferred region of parameter space is larger than the current experimental uncertainty of WMAP data.

Relativistic description of pair production of doubly heavy baryons in e+e− annihilation

International Nuclear Information System (INIS)

Martynenko, A. P.; Trunin, A. M.

2015-01-01

Relativistic corrections in the pair production of S-wave doubly heavy diquarks in electron-positron annihilation were calculated on the basis of perturbative QCD and the quark model. The relativistic corrections to the wave functions for quark bound states were taken into account with the aid of the Breit potential in QCD. Relativistic effects change substantially the nonrelativistic cross sections for pair diquark production. The yield of pairs of (ccq) doubly heavy baryons at B factories was estimated

Antibiotic Self-Medication among Non-Medical University Students in Punjab, Pakistan: A Cross-Sectional Survey

Directory of Open Access Journals (Sweden)

Ali Hassan Gillani

2017-09-01

Full Text Available Background: Antibiotic resistance is a global threat. Scarce knowledge about safe and appropriate antibiotic use is coupled with frequent self-administration, e.g., in China. This repeated self-medication poses potential risk in terms of antibiotic resistance. Low-resource countries are facing an elevated burden of antibiotic self-medication as compared to developed ones. Thus, this study focused on evaluating the pervasiveness of antibiotic self-medication in 3 universities of Southern Punjab, Pakistan. Methods: We conducted a descriptive cross-sectional survey in three government sector universities of Southern Punjab, Pakistan. The study was carried out with self-administered paper-based questionnaires. Data was analyzed using SPSS version 18.0 (IBM, Chicago, IL, USA. Results: Seven hundred twenty-seven students out of 750 (response rate 97% with a mean age ± SD of 23.0 ± 3.4 years agreed to participate in the study. The proportion of females was slightly greater (52% compared with males (48%, and almost one-third of the respondents (36% were in their 2nd year of university. Out of the total, 58.3% practiced self-medication in the preceding six months, and 326 (45% confirmed the use of antibiotics. Metronidazole was the most frequently self-medicated antibiotic (48%. Out of the total, 72% demonstrated awareness regarding the side effects of antibiotics. Diarrhea was the well-known adverse effect (38%. Forty-three percent affirmed having antibiotic resistance knowledge, and 30% knew that the irregular use of antibiotics would lead to increased antibiotic resistance. Conclusion: Despite having ample awareness of the adverse antibiotic reactions, self-medication among the university students was high and antibiotic resistance was a fairly unknown term.

Antibiotic Self-Medication among Non-Medical University Students in Punjab, Pakistan: A Cross-Sectional Survey.

Science.gov (United States)

Gillani, Ali Hassan; Ji, Wenjing; Hussain, Waqar; Imran, Ali; Chang, Jie; Yang, Caijun; Fang, Yu

2017-09-29

Background : Antibiotic resistance is a global threat. Scarce knowledge about safe and appropriate antibiotic use is coupled with frequent self-administration, e.g., in China. This repeated self-medication poses potential risk in terms of antibiotic resistance. Low-resource countries are facing an elevated burden of antibiotic self-medication as compared to developed ones. Thus, this study focused on evaluating the pervasiveness of antibiotic self-medication in 3 universities of Southern Punjab, Pakistan. Methods : We conducted a descriptive cross-sectional survey in three government sector universities of Southern Punjab, Pakistan. The study was carried out with self-administered paper-based questionnaires. Data was analyzed using SPSS version 18.0 (IBM, Chicago, IL, USA). Results : Seven hundred twenty-seven students out of 750 (response rate 97%) with a mean age ± SD of 23.0 ± 3.4 years agreed to participate in the study. The proportion of females was slightly greater (52%) compared with males (48%), and almost one-third of the respondents (36%) were in their 2nd year of university. Out of the total, 58.3% practiced self-medication in the preceding six months, and 326 (45%) confirmed the use of antibiotics. Metronidazole was the most frequently self-medicated antibiotic (48%). Out of the total, 72% demonstrated awareness regarding the side effects of antibiotics. Diarrhea was the well-known adverse effect (38%). Forty-three percent affirmed having antibiotic resistance knowledge, and 30% knew that the irregular use of antibiotics would lead to increased antibiotic resistance. Conclusion : Despite having ample awareness of the adverse antibiotic reactions, self-medication among the university students was high and antibiotic resistance was a fairly unknown term.

Multitrajectory eikonal cross sections

International Nuclear Information System (INIS)

Turner, R.E.

1983-01-01

With the use of reference and distorted transition operators, a time-correlation-function representation of the inelastic differential cross section has recently been used to obtain distorted eikonal cross sections. These cross sections involve straight-line and reference classical translational trajectories that are unaffected by any internal-state changes which have occurred during the collision. This distorted eikonal theory is now extended to include effects of internal-state changes on the translational motion. In particular, a different classical trajectory is associated with each pair of internal states. Expressions for these inelastic cross sections are obtained in terms of time-ordered cosine and sine memory functions using the Zwanzig-Feshbach projection-operator method. Explicit formulas are obtained in the time-disordered perturbation approximation

COMBINE7.1 - A Portable ENDF/B-VII.0 Based Neutron Spectrum and Cross-Section Generation Program

Energy Technology Data Exchange (ETDEWEB)

Woo Y. Yoon; David W. Nigg

2009-08-01

COMBINE7.1 is a FORTRAN 90 computer code that generates multigroup neutron constants for use in the deterministic diffusion and transport theory neutronics analysis. The cross-section database used by COMBINE7.1 is derived from the Evaluated Nuclear Data Files (ENDF/B-VII.0). The neutron energy range covered is from 20 MeV to 1.0E-5 eV. The Los Alamos National Laboratory NJOY code is used as the processing code to generate a 167 fine-group cross-section library in MATXS format for Bondarenko self-shielding treatment. Resolved resonance parameters are extracted from ENDF/B-VII.0 File 2 for a separate library to be used in an alternate Nordheim self-shielding treatment in the resolved resonance energy range. The equations solved for energy dependent neutron spectrum in the 167 fine-group structure are the B-3 or B-1 approximations to the transport equation. The fine group cross sections needed for the spectrum calculation are first prepared by Bondarenko self-shielding interpolation in terms of background cross section and temperature. The geometric lump effect, when present, is accounted for by augmenting the background cross section. Nordheim self-shielded fine group cross sections for a material having resolved resonance parameters overwrite correspondingly the existing self-shielded fine group cross sections when this option is used. The fine group cross sections in the thermal energy range are replaced by those self-shielded with the Amouyal/Benoist/Horowitz method in the three region geometry when this option is requested. COMBINE7.1 coalesces fine group cross sections into broad group macroscopic and microscopic constants. The coalescing is performed by utilizing fine-group fluxes and/or currents obtained by spectrum calculation as the weighting functions. The multigroup constant may be output in any of several standard formats including ANISN 14** free format, CCCC ISOTXS format, and AMPX working library format. ANISN-PC, a one-dimensional, discrete

COMBINE7.1 - A Portable ENDF/B-VII.0 Based Neutron Spectrum and Cross-Section Generation Program

International Nuclear Information System (INIS)

Yoon, Woo Y.; Nigg, David W.

2009-01-01

COMBINE7.1 is a FORTRAN 90 computer code that generates multigroup neutron constants for use in the deterministic diffusion and transport theory neutronics analysis. The cross-section database used by COMBINE7.1 is derived from the Evaluated Nuclear Data Files (ENDF/B-VII.0). The neutron energy range covered is from 20 MeV to 1.0E-5 eV. The Los Alamos National Laboratory NJOY code is used as the processing code to generate a 167 fine-group cross-section library in MATXS format for Bondarenko self-shielding treatment. Resolved resonance parameters are extracted from ENDF/B-VII.0 File 2 for a separate library to be used in an alternate Nordheim self-shielding treatment in the resolved resonance energy range. The equations solved for energy dependent neutron spectrum in the 167 fine-group structure are the B-3 or B-1 approximations to the transport equation. The fine group cross sections needed for the spectrum calculation are first prepared by Bondarenko self-shielding interpolation in terms of background cross section and temperature. The geometric lump effect, when present, is accounted for by augmenting the background cross section. Nordheim self-shielded fine group cross sections for a material having resolved resonance parameters overwrite correspondingly the existing self-shielded fine group cross sections when this option is used. The fine group cross sections in the thermal energy range are replaced by those self-shielded with the Amouyal/Benoist/Horowitz method in the three region geometry when this option is requested. COMBINE7.1 coalesces fine group cross sections into broad group macroscopic and microscopic constants. The coalescing is performed by utilizing fine-group fluxes and/or currents obtained by spectrum calculation as the weighting functions. The multigroup constant may be output in any of several standard formats including ANISN 14** free format, CCCC ISOTXS format, and AMPX working library format. ANISN-PC, a one-dimensional, discrete

FEMA DFIRM Cross Sections

Data.gov (United States)

Minnesota Department of Natural Resources — FEMA Cross Sections are required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally...

Measurement of the total hadronic cross section in e sup + e minus annihilation at radical s =29 GeV

Energy Technology Data Exchange (ETDEWEB)

von Zanthier, C.; de Boer, W.; Grindhammer, G.; Hylen, J.; Harral, B.; Hearty, C.; Labarga, L.; Matthews, J.; Schaad, M.; Abrams, G.; Adolphsen, C.E.; Akerlof, C.; Alexander, J.P.; Alvarez, M.; Baden, A.R.; Ballam, J.; Barish, B.C.; Barklow, T.; Barnett, B.A.; Bartelt, J.; Blockus, D.; Bonvicini, G.; Boyarski, A.; Boyer, J.; Brabson, B.; Breakstone, A.; Brom, J.M.; Bulos, F.; Burchat, P.R.; Burke, D.L.; Butler, F.; Calvino, F.; Cence, R.J.; Chapman, J.; Cords, D.; Coupal, D.P.; DeStaebler, H.C.; Dorfan, D.E.; Dorfan, J.M.; Drell, P.S.; Feldman, G.J.; Fernandez, E.; Field, R.C.; Ford, W.T.; Fordham, C.; Frey, R.; Fujino, D.; Gan, K.K.; Gidal, G.; Glanzman, T.; Goldhaber, G.; Green, A.; Grosse-Wiesmann, P.; Haggerty, J.; Hanson, G.; Harr, R.; Harris, F.A.; Hawkes, C.M.; Hayes, K.; Herrup, D.; Heusch, C.A.; Himel, T.; Hoenk, M.; Hutchinson, D.; Innes, W.R.; Jaffre, M.; Jaros, J.A.; Juricic, I.; Kadyk, J.A.; Karlen, D.; Kent, J.; Klein, S.R.; Koska, W.; Kozanecki, W.; Lankford, A.J.; Larse

1991-01-01

A precise measurement of the ratio {ital R} of the total cross section {ital e}{sup +}{ital e{minus}}{r arrow}hadrons to the pointlike cross section {ital e}{sup +}{ital e{minus}}{r arrow}{mu}{sup +}{mu}{sup {minus}} at a center-of-mass energy of 29.0 GeV is presented. The data were taken with the upgraded Mark II detector at the SLAC storage ring PEP. The result is {ital R}=3.92{plus minus}0.05{plus minus}0.09. The luminosity has been determined with three independent luminosity monitors measuring Bhabha scattering at different angular intervals. Recent calculations of higher-order QED radiative corrections are used to estimate the systematic error due to missing higher-order radiative corrections in the Monte Carlo event generators.

Cross sectional evaluation of awareness of prevention of dental ...

African Journals Online (AJOL)

Cross sectional evaluation of awareness of prevention of dental caries among general paediatricians in Ghaziabad district, India. ... Pre‑tested, structured and self administered questionnaire was used in the survey and data analysis was done by using 'SPSS' software version 16.0 (IBM, United States). Results: Our study ...

Two-body neutral final states produced in antiproton-proton annihilations at 2.911≤√(s)≤3.686 GeV

International Nuclear Information System (INIS)

Bharadwaj, V.; Church, M.; Hahn, A.; Hsueh, S.; Marsh, W.; Peoples, J. Jr.; Pordes, S.; Rapidis, P.; Ray, R.; Werkema, S.; Bettoni, D.; Calabrese, R.; Dalpiaz, P.; Dalpiaz, P.F.; Gianoli, A.; Luppi, E.; Martini, M.; Petrucci, F.; Savrie, M.; Buzzo, A.; Macri, M.; Marinelli, M.; Pallavicini, M.; Passaggio, S.; Patrignani, C.; Pia, M.G.; Santroni, A.; Blanford, G.; Broemmelsiek, D.; Fast, J.; Gollwitzer, K.; Mandelkern, M.; Marques, J.; Schultz, J.; Smith, A.; Van Drunen, E.; Weber, M.F.; Zioulas, G.; Dimitroyannis, D.; Ginsburg, C.M.; Masuzawa, M.; Peoples, J. Jr.; Ray, R.; Rosen, J.; Sarmiento, M.; Seth, K.K.; Trokenheim, S.; Zhao, J.; Armstrong, T.A.; Hasan, M.; Lewis, R.; Majewska, A.M.; Reid, J.; Smith, G.A.; Zhang, Y.; Biino, C.; Borreani, G.; Ceccucci, A.; Cester, R.; Govi, G.; Marchetto, F.; Menichetti, E.; Migliori, A.; Mussa, R.; Palestini, S.; Pastrone, N.; Rinaudo, G.; Roccuzzo, B.; Sozzi, M.

1997-01-01

We have performed an experiment in the Antiproton Accumulator at Fermilab to study two-body neutral final states formed in bar pp annihilations. Differential cross sections are determined in the center-of-mass energy range 2.911 0 π 0 , ηπ 0 , ηη, π 0 γ, and γγ. The energy dependence of differential cross sections at 90 degree in the center of mass is studied to test the predictions of phenomenological QCD scaling hypotheses which predict power-law dependence. copyright 1997 The American Physical Society

Comparison of integral cross section values of several cross section libraries in the SAND-II format

International Nuclear Information System (INIS)

Zijp, W.L.; Nolthenius, H.J.

1976-09-01

A comparison of some integral cross-section values for several cross-section libraries in the SAND-II format is presented. The integral cross-section values are calculated with the aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross-section libraries used have all the SAND-II format. Discrepancies between cross-sections in the different libraries are indicated but not discussed

Parental Use of Antibiotics as Self Medication to Their School Going Children: A Cross Sectional Study

Directory of Open Access Journals (Sweden)

Yugantara R. Kadam

2018-01-01

Full Text Available Background: Self-medication with antibiotics constitutes a major form of irrational use of medicine and it is associated with risk of developing antibiotic resistance. Parents many times use antibiotics as self medication for their children which is hazardous. There is a need to find out such practices if they are happening. Aim and Objectives: to find out the prevalence and practices of antibiotics use as self medication in children amongst the parents and reasons for the same. Material and Methods: It was a cross-sectional study. Schools from Sangli-Miraj-Kupwad Corporation area were the study place. Parents of primary and secondary school students were the study subjects. The sample size was 1407. Cluster sampling method was used. The study duration was of 6 months. The questionnaire was used as a study tool. Results: The prevalence of non prescriptional parental use of antibiotic for school going children was 22.8%. Most common symptom treated was runny nose (41.43%. Majority parents (35.51% selected antibiotic by using their own experience. Commonest reason was 'convenience' (27.72%. Gender and type of family are the strong predictors for self-medication with antibiotic for children. Conclusion: Parental use of non prescribed antibiotic was high. Risk for parental use of self medication was high with nuclear families and mothers.

Relativistic photon-Maxwellian electron cross sections

International Nuclear Information System (INIS)

Wienke, B.R.; Lathrop, B.L.; Devaney, J.J.

1986-01-01

Temperature corrected cross sections, complementing the Klein-Nishina set, are developed for astrophysical, plasma, and transport applications. The set is obtained from a nonlinear least squares fit to the exact photon-Maxwellian electron cross sections, using the static formula as the asymptotic basis. Two parameters are sufficient (two decimal places) to fit the exact cross sections over a range of 0-100 keV in electron temperature, and 0-1 MeV in incident photon energy. The fit is made to the total cross sections, yet the parameters predict both total and differential scattering cross sections well. Corresponding differential energy cross sections are less accurate. An extended fit to (just) the total cross sections, over the temperature and energy range 0-5 MeV, is also described. (author)

Formats and processing of evaluated nuclear data into multigroup cross-sections

International Nuclear Information System (INIS)

Motta, M.

1984-01-01

The first part of these lectures concerns the data in nuclear files and their manipulation. The structure of the data files as divided into the resonance region (subdivided into the resolved and the unresolved regions) and the continuum region is presented. The reactions concerned are the elastic scattering; the radiative capture and the fission methods for averaging the cross sections are given. Then, the group averaging formulas and the self-shielding factors are presented in some detail. The second part concerns a presentation of nuclear data files handling and conversion. The main libraries are listed and several maintenance computer codes presented. The way the conversion among different files is handled is also presented. The listings of several BASIC programs for different cross section calculations are given. These codes are self-guided

Neutron cross sections in the unresolved resonance region

International Nuclear Information System (INIS)

Janeva, N.; Lukyanov, A.; Koyumdjieva, N.; Volev, K.

2005-01-01

In this work a development of the characteristic function model, created to reveal the resonance cross section structure in the unresolved resonance region is presented. The main advantage of this model is the calculation of resonance averaged self-shielding factors analytically. To determine average values of the cross sections and their functionals the function of joint statistical distribution of the R-matrix real and imaginary parts should be used. The characteristic function of such distribution is determined and the resonance ladder for the unresolved region is optimized to calculate the group averaged functionals in the same way as it is in the resolved resonance region. The main advantage of this model is the calculation of resonance averaged self-shielding factors analytically. The neutron width energy dependence leads to some deformation in the shape of resonances. This deformation is most apparent near the inelastic scattering threshold. For the case when the inelastic channel momentum is zero we present the formula for level shape bellow and over the inelastic threshold and the calculated resonance deformation in dependence of the position of the resonance in respect to the threshold. (authors)

Solvable single-species aggregation-annihilation model for chain-shaped cluster growth

International Nuclear Information System (INIS)

Ke Jianhong; Lin Zhenquan; Zheng Yizhuang; Chen Xiaoshuang; Lu Wei

2007-01-01

We propose a single-species aggregation-annihilation model, in which an aggregation reaction between two clusters produces an active cluster and an annihilation reaction produces an inert one. By means of the mean-field rate equation, we respectively investigate the kinetic scaling behaviours of three distinct systems. The results exhibit that: (i) for the general aggregation-annihilation system, the size distribution of active clusters consistently approaches the conventional scaling form; (ii) for the system with the self-degeneration of the cluster's activities, it takes the modified scaling form; and (iii) for the system with the self-closing of active clusters, it does not scale. Moreover, the size distribution of inert clusters with small size takes a power-law form, while that of large inert clusters obeys the scaling law. The results also show that all active clusters will eventually transform into inert ones and the inert clusters of any size can be produced by such an aggregation-annihilation process. This model can be used to mimic the chain-shaped cluster growth and can provide some useful predictions for the kinetic behaviour of the system

Effects of relativistic small radial component on atomic photoionization cross sections

International Nuclear Information System (INIS)

Liu Xiaobin; Xing Yongzhong; Sun Xiaowei

2008-01-01

The effects of relativistic small radial component on atomic photoionization cross sections have been studied within relativistic average self-consistent field theory. Relativistic effects are relatively unimportant for low photon energy, along with a review of high-energy photoionization the relativistic effects are quite important. The effects of relativistic small radial component on photoionization process should show breakdown when the nuclear finite-size effects is taken into account. The compression of wavefunction into the space near nucleus is so strong in highly charged ions that the electronic radius greatly decreases, and the effects of relativistic small radial component on photoionization cross sections turn to stronger than ordinary atoms. Since relativistic effects are extremely sensitive to the behavior of small radial component, the results are in good agreement with relativistic effects on photoionization cross section. (authors)

Comparing antibiotic self-medication in two socio-economic groups in Guatemala City: a descriptive cross-sectional study.

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Ramay, Brooke M; Lambour, Paola; Cerón, Alejandro

2015-04-27

Self-medication with antibiotics may result in antimicrobial resistance and its high prevalence is of particular concern in Low to Middle Income Countries (LMIC) like Guatemala. A better understanding of self-medication with antibiotics may represent an opportunity to develop interventions guiding the rational use of antibiotics. We aimed to compare the magnitude of antibiotic self-medication and the characteristics of those who self-medicate in two pharmacies serving disparate socio-economic communities in Guatemala City. We conducted a descriptive, cross-sectional study in one Suburban pharmacy and one City Center pharmacy in Guatemala City. We used a questionnaire to gather information about frequency of self-medication, income and education of those who self-medicate. We compared proportions between the two pharmacies, using two-sample z-test as appropriate. Four hundred and eighteen respondents completed the survey (221 in the Suburban pharmacy and 197 in the City Center pharmacy). Most respondents in both pharmacies were female (70%). The reported monthly income in the suburban pharmacy was between $1,250.00-$2,500.00, the city-center pharmacy reported a monthly income between $125.00- $625.00 (p Guatemala City. Additionally, self-medicating respondents were most often women and most commonly self-medicated with amoxicillin. Our findings support future public health interventions centered on the regulation of antibiotic sales and on the potential role of the pharmacist in guiding prescription with antibiotics in Guatemala.

COMBINE7.0 - A Portable ENDF/B-VII.0 Based Neutron Spectrum and Cross-Section Generation Program

Energy Technology Data Exchange (ETDEWEB)

Woo Y. Yoon; David W. Nigg

2008-09-01

COMBINE7.0 is a FORTRAN 90 computer code that generates multigroup neutron constants for use in the deterministic diffusion and transport theory neutronics analysis. The cross-section database used by COMBINE7.0 is derived from the Evaluated Nuclear Data Files (ENDF/B-VII.0). The neutron energy range covered is from 20 MeV to 1.0E-5 eV. The Los Alamos National Laboratory NJOY code is used as the processing code to generate a 167 finegroup cross-section library in MATXS format for Bondarenko self-shielding treatment. Resolved resonance parameters are extracted from ENDF/B-VII.0 File 2 for a separate library to be used in an alternate Nordheim self-shielding treatment in the resolved resonance energy range. The equations solved for energy dependent neutron spectrum in the 167 fine-group structure are the B-3 or B-1 approximations to the transport equation. The fine group cross sections needed for the spectrum calculation are first prepared by Bondarenko selfshielding interpolation in terms of background cross section and temperature. The geometric lump effect, when present, is accounted for by augmenting the background cross section. Nordheim self-shielded fine group cross sections for a material having resolved resonance parameters overwrite correspondingly the existing self-shielded fine group cross sections when this option is used. The fine group cross sections in the thermal energy range are replaced by those selfshielded with the Amouyal/Benoist/Horowitz method in the three region geometry when this option is requested. COMBINE7.0 coalesces fine group cross sections into broad group macroscopic and microscopic constants. The coalescing is performed by utilizing fine-group fluxes and/or currents obtained by spectrum calculation as the weighting functions. The multigroup constant may be output in any of several standard formats including ANISN 14** free format, CCCC ISOTXS format, and AMPX working library format. ANISN-PC, a onedimensional, discrete

COMBINE7.0 - A Portable ENDF/B-VII.0 Based Neutron Spectrum and Cross-Section Generation Program

International Nuclear Information System (INIS)

Yoon, Woo Y.; Nigg, David W.

2008-01-01

COMBINE7.0 is a FORTRAN 90 computer code that generates multigroup neutron constants for use in the deterministic diffusion and transport theory neutronics analysis. The cross-section database used by COMBINE7.0 is derived from the Evaluated Nuclear Data Files (ENDF/B-VII.0). The neutron energy range covered is from 20 MeV to 1.0E-5 eV. The Los Alamos National Laboratory NJOY code is used as the processing code to generate a 167 finegroup cross-section library in MATXS format for Bondarenko self-shielding treatment. Resolved resonance parameters are extracted from ENDF/B-VII.0 File 2 for a separate library to be used in an alternate Nordheim self-shielding treatment in the resolved resonance energy range. The equations solved for energy dependent neutron spectrum in the 167 fine-group structure are the B-3 or B-1 approximations to the transport equation. The fine group cross sections needed for the spectrum calculation are first prepared by Bondarenko selfshielding interpolation in terms of background cross section and temperature. The geometric lump effect, when present, is accounted for by augmenting the background cross section. Nordheim self-shielded fine group cross sections for a material having resolved resonance parameters overwrite correspondingly the existing self-shielded fine group cross sections when this option is used. The fine group cross sections in the thermal energy range are replaced by those selfshielded with the Amouyal/Benoist/Horowitz method in the three region geometry when this option is requested. COMBINE7.0 coalesces fine group cross sections into broad group macroscopic and microscopic constants. The coalescing is performed by utilizing fine-group fluxes and/or currents obtained by spectrum calculation as the weighting functions. The multigroup constant may be output in any of several standard formats including ANISN 14** free format, CCCC ISOTXS format, and AMPX working library format. ANISN-PC, a onedimensional, discrete

Integral nucleus-nucleus cross sections

International Nuclear Information System (INIS)

Barashenkov, V.S.; Kumawat, H.

2003-01-01

Expressions approximating the experimental integral cross sections for elastic and inelastic interactions of light and heavy nuclei at the energies up to several GeV/nucleon are presented. The calculated cross sections are inside the corridor of experimental errors or very close to it. Described in detail FORTRAN code and a numerical example of the cross section approximation are also presented

Photon-splitting cross sections

International Nuclear Information System (INIS)

Johannessen, A.M.; Mork, K.J.; Overbo, I.

1980-01-01

The differential cross section for photon splitting (scattering of one photon into two photons) in a Coulomb field, obtained earlier by Shima, has been integrated numerically to yield various differential cross sections. Energy spectra differential with respect to the energy of one of the outgoing photons are presented for several values of the primary photon energy. Selected examples of recoil momentum distributions and some interesting doubly or multiply differential cross sections are also given. Values for the total cross section are obtained essentially for all energies. The screening effect caused by atomic electrons is also taken into account, and is found to be important for high energies, as in e + e - pair production. Comparisons with various approximate results obtained by previous authors mostly show fair agreement. We also discuss the possibilities for experimental detection and find the most promising candidate to be a measurement of both photons, and their energies, at a moderately high energy

Constraint on dark matter annihilation with dark star formation using Fermi extragalactic diffuse gamma-ray background data

International Nuclear Information System (INIS)

Yuan, Qiang; Yue, Bin; Chen, Xuelei; Zhang, Bing

2011-01-01

It has been proposed that during the formation of the first generation stars there might be a ''dark star'' phase in which the power of the star comes from dark matter annihilation. The adiabatic contraction process to form the dark star would result in a highly concentrated density profile of the host halo at the same time, which may give enhanced indirect detection signals of dark matter. In this work we investigate the extragalactic γ-ray background from dark matter annihilation with such a dark star formation scenario, and employ the isotropic γ-ray data from Fermi-LAT to constrain the model parameters of dark matter. The results suffer from large uncertainties of both the formation rate of the first generation stars and the subsequent evolution effects of the host halos of the dark stars. We find, in the most optimistic case for γ-ray production via dark matter annihilation, the expected extragalactic γ-ray flux will be enhanced by 1-2 orders of magnitude. In such a case, the annihilation cross section of the supersymmetric dark matter can be constrained to the thermal production level, and the leptonic dark matter model which is proposed to explain the positron/electron excesses can be well excluded. Conversely, if the positron/electron excesses are of a dark matter annihilation origin, then the early Universe environment is such that no dark star can form

Association between sporting event attendance and self-rated health: an analysis of multiyear cross-sectional national data in Japan.

Science.gov (United States)

Inoue, Yuhei; Sato, Mikihiro; Nakazawa, Makoto

2018-01-01

This study examined the extent to which sporting event attendance is associated with self-rated health. Drawing from an economic model of health production and psychological research on the health benefits of psychosocial resources, sporting event attendance was hypothesized to have a positive relationship with self-rated health. A two-level multilevel ordered logistic regression was used to analyze multiyear cross-sectional data collected from national surveys in Japan. The results demonstrate that, controlling for the effects of personal and environmental characteristics, sporting event attendance positively correlates with self-rated health over a 12-year period. Specifically, when compared to individuals who did not attend any sporting event during the past year, those who attended a sporting event were 33% more likely to indicate a higher level of self-rated health. These findings provide evidence for a positive association between sport spectatorship and the perception of general health and contribute to the literature examining the relationship between sport spectatorship and health outcomes.

Resonance analysis and evaluation of the 235U neutron induced cross sections

International Nuclear Information System (INIS)

Leal, L.C.

1990-06-01

Neutron cross sections of fissile nuclei are of considerable interest for the understanding of parameters such as resonance absorption, resonance escape probability, resonance self-shielding,and the dependence of the reactivity on temperature. In the present study, new techniques for the evaluation of the 235 U neutron cross sections are described. The Reich-Moore formalism of the Bayesian computer code SAMMY was used to perform consistent R-matrix multilevel analyses of the selected neutron cross-section data. The Δ 3 -statistics of Dyson and Mehta, along with high-resolution data and the spin-separated fission cross-section data, have provided the possibility of developing a new methodology for the analysis and evaluation of neutron-nucleus cross sections. The results of the analysis consists of a set of resonance parameters which describe the 235 U neutron cross sections up to 500 eV. The set of resonance parameters obtained through a R-matrix analysis are expected to satisfy statistical properties which lead to information on the nuclear structure. The resonance parameters were tested and showed good agreement with the theory. It is expected that the parametrization of the 235 U neutron cross sections obtained in this dissertation represents the current state of art in data as well as in theory and, therefore, can be of direct use in reactor calculations. 44 refs., 21 figs., 8 tabs

Annihilation of antiprotons at rest in 3He and 4He

International Nuclear Information System (INIS)

Balestra, F.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Fava, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F.; Bendiscioli, G.; Rotondi, A.; Salvini, P.; Zenoni, A.; Batusov, Yu.A.; Bunyatov, S.A.; Falomkin, I.V.; Nichitiu, F.; Pontecorvo, G.B.; Sapozhnikov, M.G.; Tretyak, V.I.; Guaraldo, C.; Maggiora, A.; Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M.; Breivik, F.O.; Jacobsen, T.; Soerensen, S.O.

1987-01-01

At LEAR of CERN the annihilation of antiprotons, stopping in 3 He and 4 He filling a self-shunted streamer chamber in a magnetic field, has been studied. The charged-particle multiplicities have been measured and the relative probabilities of π - production in anti p 3 He and anti p 4 He annihilation events have been obtained. The ratio between the anti p annihilation probability on the neutron and the proton for 3 He and 4 He has been deduced to be about half the value obtained for 2 H in bubble chamber experiments. The analysis of the results shows that this difference cannot be due only to the pion final-state interaction or to the shadow effect of the nucleons of the nuclei. The probability of anti p annihilation at rest on a proton bound in the nucleus results to be twice as high as that on a bound neutron, showing the dominance of annihilation in the I=0 isospin states. (orig.)

A Cross-Section Adjustment Method for Double Heterogeneity Problem in VHTGR Analysis

International Nuclear Information System (INIS)

Yun, Sung Hwan; Cho, Nam Zin

2011-01-01

Very High Temperature Gas-Cooled Reactors (VHTGRs) draw strong interest as candidates for a Gen-IV reactor concept, in which TRISO (tristructuralisotropic) fuel is employed to enhance the fuel performance. However, randomly dispersed TRISO fuel particles in a graphite matrix induce the so-called double heterogeneity problem. For design and analysis of such reactors with the double heterogeneity problem, the Monte Carlo method is widely used due to its complex geometry and continuous-energy capabilities. However, its huge computational burden, even in the modern high computing power, is still problematic to perform wholecore analysis in reactor design procedure. To address the double heterogeneity problem using conventional lattice codes, the RPT (Reactivityequivalent Physical Transformation) method considers a homogenized fuel region that is geometrically transformed to provide equivalent self-shielding effect. Another method is the coupled Monte Carlo/Collision Probability method, in which the absorption and nu-fission resonance cross-section libraries in the deterministic CPM3 lattice code are modified group-wise by the double heterogeneity factors determined by Monte Carlo results. In this paper, a new two-step Monte Carlo homogenization method is described as an alternative to those methods above. In the new method, a single cross-section adjustment factor is introduced to provide self-shielding effect equivalent to the self-shielding in heterogeneous geometry for a unit cell of compact fuel. Then, the homogenized fuel compact material with the equivalent cross-section adjustment factor is used in continuous-energy Monte Carlo calculation for various types of fuel blocks (or assemblies). The procedure of cross-section adjustment is implemented in the MCNP5 code

Comparison of integral cross section values of several cross section libraries in the SAND-II format

International Nuclear Information System (INIS)

Zijp, W.L.; Nolthenius, H.J.

1978-01-01

A comparison of some integral cross section values for several cross section libraries in the SAND-II format is presented. The integral cross section values are calculated with aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross section libraries used have all the SAND-II format. (author)

A cross-sectional study on self-management of pressure ulcer prevention in paraplegic patients.

Science.gov (United States)

de Laat, H E W; de Munter, A C; van der Burg, M J; Ulrich, D J O; Kloeters, O

2017-02-01

Little is known about health activation and self-management behavior in preventing pressure ulcers (PU) in paraplegic patients. Therefore this study aimed to describe the extent of health activation and self-management behavior in paraplegics to prevent PU's and associations between this behavior and patient characteristics. Furthermore, we aimed to find differences in health activation in paraplegics who never had a PU compared to paraplegics with a previous history of PU's or a new-onset PU's. A cross-sectional survey on health activation and self-management behavior was conducted among adult paraplegics recruited from two rehabilitation centers in the Netherlands. The Patient Activation Measure (PAM-score) was used to measure the extent of health activation. Patient statements on their level of self management behavior to prevent PU were evaluated. The mean PAM-score (0-100) was 54 (±8.1; n = 162) indicating a low level of health activation. Two indicators turned out to be statistically significant associated with health activation: level of education (OR = 2.2, p = 0.017) and degree of paraplegia (OR = 2.8, p = 0.036). Evaluation of health activation levels amongst paraplegics with or without a PU- history showed no significant difference. Analysis of patients statements demonstrated a large discrepancy between intended and actual behavior to prevent pressure ulcers. Level of education and level of paraplegia are significantly associated with health activation. A positive PU-history is not associated with future responsible behavior nor for compliant behavior in terms of health management. Copyright © 2016 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Jet inclusive cross sections

International Nuclear Information System (INIS)

Del Duca, V.

1992-11-01

Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons

What do Key Stakeholders Think About HIV Self-Testing in Canada? Results from a Cross-Sectional Survey.

Science.gov (United States)

Pai, N Pant; Smallwood, M; Gulati, D; Lapczak, N; Musten, A; Gaydos, C; Johnston, C; Steben, M; Wong, T; Engel, N; Kim, J

2018-02-01

Human immunodeficiency virus (HIV) self-testing presents an empowering alternative to facility-based testing for reaching undiagnosed HIV infected individuals, but is not currently available in Canada. We surveyed stakeholders (clinical providers, public health professionals, researchers) engaged in HIV testing initiatives nationwide to identify the concerns, opportunities and challenges to implementing HIV self-testing in Canada. An online cross-sectional survey was disseminated by the Canadian Institutes of Health Research Centre for REACH 2.0 National HIV & sexually transmitted and blood borne infections working group to stakeholders nationwide, with a target sample size of 200. Quantitative and qualitative data were analyzed using a mixed-methods, respondent-informed approach, to inform subsequent HIV self-testing in a country where self-testing is not yet accessible. A total of 183 responses were received. A majority (70.7%) (128/181) felt that self-testing was a necessary investment to reach the undiagnosed. 64.6% (117/181) felt that self-tests should be made available to their clients and 71.5% (128/179) of respondents agreed that self-test instructions required improvements. However, 50% (90/180) felt that self-testing will pose an economic challenge to current HIV testing models. Regardless, 21% urged for timely action and availability of HIV self-tests. Thematic analyses reflected the following concerns: (a) need for affordable self-tests, (b) need for expedited, customized, and accessible linkages to counselling, (c) concern for patients to cope with positive self-test results, (d) accuracy of self-tests to detect acute HIV and (e) liability in the context of non-disclosure. Stakeholders agreed to the provision of an option of HIV self-testing to reach the undiagnosed individuals. Concerns regarding costs and accuracy of self-tests, expedited linkages to counselling, and integration of self-test within prevailing HIV testing models, will need to be

Λ production in e+e- annihilations at 29 GeV

International Nuclear Information System (INIS)

Abachi, S.; Baringer, P.; Beltrami, I.

1986-05-01

This paper presents measurements of the inclusive production cross sections of Λ baryons in e + e - annihilations at √s = 29 GeV. The data sample corresponds to an integrated luminosity of 256 pb -1 collected with the High Resolution Spectrometer at PEP. Comparisons are made to the predictions of the Lund model. The data are well described using a strange diquark suppression parameter, (us/ud)/(s/d), of 0.89 +- 0.10/sub -0.16//sup +0.56/, and the measured Λ/sub c/ → Λ + X branching ratio of 23 +- 10%. No polarization is observed in the Λ decays. 17 refs., 5 figs

Time perspective, optimistic bias, and self-control among different statuses of university smokers in China: a cross-sectional study.

Science.gov (United States)

Xu, Ying; Yang, Yang; Ma, Xiao

2018-01-09

Risk behavior often seems 'self-defeating' to the observers. Most people understand the basic health-related knowledge, but some of them still choose to continue risk behaviors, especially for the young. This study aimed to examine time perspective, optimism bias and self control correlated with smoking behavior in Chinese college students. A cross-sectional survey enrolling 3016 university students in Chengdu City, Sichuan Province, China. Influence Factors were identified using multiple logistic regression analyses. Prevalence of current smoking was 20.92% (631 smokers), including 272 daily smokers (9.02%) and 359 non-daily smokers (11.90%). Future-oriented time perspective, general capacity for self-discipline, reliability and ethnicity were protective factors of smoking behavior. Possibility of self-suffering diseases and gender were risk factors of smoking behavior. Smoking in University of Chengdu, China is a severe problem. Results in this research have suggested that irrespective of the smoking level, improving health-related knowledge, time management awareness and self-control ability may contribute to reducing the prevalence of smoking behavior.

Vaccination behaviour influences self-report of influenza vaccination status: a cross-sectional study among health care workers.

Directory of Open Access Journals (Sweden)

Anna Llupià

Full Text Available BACKGROUND: Published influenza vaccination coverage in health care workers (HCW are calculated using two sources: self-report and vaccination records. The objective of this study was to determine whether self-report is a good proxy for recorded vaccination in HCW, as the degree of the relationship is not known, and whether vaccine behaviour influences self-reporting. METHODS: A cross-sectional study was conducted using a self-administered survey during September 2010. Considering the vaccination record as the gold standard of vaccination, the properties of self-report as a proxy of the record (sensitivity, specificity, positive predictive value, negative predictive value were calculated. Concordance between the vaccination campaigns studied (2007-2010 was made using the Kappa index, and discordance was analyzed using McNemar's test. RESULTS: 248 HCW responded. The 95% confidence intervals of coverage according to the vaccination record and to self-report overlapped, except for 2007, and the Kappa index showed a substantial concordance, except for 2007. McNemar's test suggested that differences between discordant cases were not due to chance and it was found that the proportion of unvaccinated discordant cases was higher than that of vaccinated discordant cases. CONCLUSIONS: In our study population, self-reported influenza vaccination coverage in HCW in the previous two years is a good proxy of the vaccination record. However, vaccination behaviour influences the self-report and explains a trend to overestimate coverage in self-reporting compared to the vaccination record. The sources of coverage should be taken into account whenever comparisons are made.

Electron collision cross sections of mercury

International Nuclear Information System (INIS)

Suzuki, Susumu; Kuzuma, Kiyotaka; Itoh, Haruo

2006-01-01

In this paper, we propose a new collision cross section set for mercury which revises the original set summarized by Hayashi in 1989. Hanne reported three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) determined from an electron beam experiment in 1988. As a matter for regret, no attentive consideration was given to combining these three excitation cross sections with the cross section set of Hayashi. Therefore we propose a new set where these three excitation cross sections are included. In this study, other two excitation cross sections (6 1 P 1 , 6 3 D 3 ) except for the three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) are taken from the original set of Hayashi. The momentum transfer cross section and the ionization collision cross section are also taken from Hayashi. A Monte Carlo Simulation (MCS) technique is applied for evaluating our new cross section set. The present results of the electron drift velocity and the ionization coefficient are compared to experimental values. Agreement is secured in relation to the electron drift velocity for 1.5 Td 2 ) is the reduced electric field, E (V/cm) is the electric field, N (1/cm 3 ) is the number density of mercury atoms at 0degC, 1 Torr, E/N is also equal to 2.828 x 10 -17 E/p 0 from the relation of the ideal gas equation, p 0 (Torr) is gas pressure at 0degC, 1 Torr=1.33322 x 10 -2 N/cm -2 and 10 -17 V/cm 2 is called 1 Td. Thus it is ensured that our new cross section set is reasonable enough to be used up to 100 eV when considering with the electron drift velocity and the ionization coefficient. (author)

Sensitivity of orthopositronium annihilation to density fluctuations in ethane gas

International Nuclear Information System (INIS)

Eftekhari, A.

1982-01-01

The annihilation rates of orthopositronium (o-Ps) and free positrons and positronium formation fractions have been measured in gaseous ethane at seven temperatures between 295 and 377 K for densities in the range 1.2-286 amagat. The pick off quenching rate of o-Ps is observed to vary with temperature at low densities of ethane. The observed behavior of the o-Ps annihilation rates with density and temperature is interpreted in terms of density fluctuations in ethane gas. A simple theoretical model is developed which explains the observed annihilation behavior reasonably well at those temperatures and densities where density fluctuations are small. The annihilation rates of flow-energy positrons indicate the formation of positron-ethane collision complexes and self-trapping of positrons in clusters of ethane molecules. The o-Ps yields appear to be independent of temperature and show a strong dependence on the density of the gas

Cross-section methodology in SIMMER

International Nuclear Information System (INIS)

Soran, P.D.

1975-11-01

The cross-section methodology incorporated in the SIMMER code is described. Data base for all cross sections is the ENDF/B system with various progressing computer codes to group collapse and modify the group constants which are used in SIMMER. Either infinitely dilute cross sections or the Bondarenko formalism can be used in SIMMER. Presently only a microscopic treatment is considered, but preliminary macroscopic algorithms have been investigated

Cross-section methodology in SIMMER

International Nuclear Information System (INIS)

Soran, P.D.

1976-05-01

The cross-section methodology incorporated in the SIMMER code is described. Data base for all cross sections is the ENDF/B system with various progressing computer codes to group collapse and modify the group constants which are used in SIMMER. Either infinitely dilute cross sections or the Bondarenko formalism can be used in SIMMER. Presently only a microscopic treatment is considered, but preliminary macroscopic algorithms have been investigated

Fast-neutron total and scattering cross sections of 58Ni

International Nuclear Information System (INIS)

Jorgensen, C.B.; Guenther, P.T.; Smith, A.B.; Whalen, J.F.

1981-09-01

Neutron total cross sections of 58 Ni were measured at 25 keV intervals from 0.9 to 4.5 MeV with 50 to 100 keV resolutions. Attention was given to self-shielding corrections to the observed total cross sections. Differential elastic- and inelastic-scattering cross sections were measured at 50 keV intervals from 1.35 to 4.0 MeV with 50 to 100 keV resolutions. Inelastic excitation of levels at 1.458 +- 0.009, 2.462 +- 0.010, 2.791 +- 0.015, 2.927 +- 0.012 and 3.059 +- 0.025 MeV was observed. The experimental results were interpreted in terms of optical-statistical and coupled-channels models. A spherical optical-statistical model was found generally descriptive of an energy-average of the experimental results. However, detailed considerations suggested significant contributions from direct-vibrational interactions, particularly associated with the excitation of the first 2+ level

XNWLUP, Graphical user interface to plot WIMS-D library multigroup cross sections

International Nuclear Information System (INIS)

Ganesan, S.; Jagannathan, V.; Thiyagarajan, T.K.

2005-01-01

1 - Description of program or function: XnWlup is a computer program with user-friendly graphical interface to help the users of WIMS-D library to enable quick visualisation of the plots of the energy dependence of the multigroup cross sections of any nuclide of interest. This software enables the user to generate and view the histogram of 69 multi-group cross sections as a function of neutron energy under Microsoft Windows environment. This software is designed using Microsoft Visual C++ and Microsoft Foundation Classes Library. IAEA1395/05: New features of version 3.0: - Plotting absorption and fission cross sections of resonant nuclide after applying the self-shielding cross section. - Plotting the data of Resonant Integral table, as a function of dilution cross section for a selected temperature and for a given energy group. - Plotting the data of Resonant Integral table, as a function of temperature for a selected background dilution cross section and for a given energy group. - Clearing all the graphs except one graph from the display screen is easily done by using a tool bar button. - Displaying the coordinate of the cursor point with appropriate units. 2 - Methods: XnWlup helps to obtain histogram plots of the values of cross section data of an element/isotope available as 69-group WIMS-D library as a function of energy bins. The software XnWlup is developed with this graphical user interface in order to help those users who frequently refer to the WIMS-D library cross section data of neutron-nuclear reactions. The software also helps to produce handbook of WIMS-D cross sections

Measurement of photonuclear cross sections from 30 to 140 MeV for intermediate and heavy mass nuclei (Sn, Ce, Ta, Pb and U)

International Nuclear Information System (INIS)

Lepretre, A.

1982-06-01

The total photonuclear absorption cross section for Sn, Ce, Ta, Pb and U has been studied from 25 to 140 MeV using a continuously variable monochromatic photon beam obtained from the annihilation in flight of monoenergetic positrons. The basic experimental results are a set of data giving sums of inclusive multiple photoneutron production cross sections of the form σsup(j) (Esub(γ) = Σsub(i=j)σ(γ,in) for neutron multiplicities ranging from j=1 to 12. From these data the total photonuclear absorption cross section σ(tot : Esub(γ)) has been deduced. It is concluded that Levinger's modified quasi-deuteron model describes the total cross sections reasonably well. When these data are combined with lower energy data and integrated to 140 MeV they indicate the need for an enhancement factor K for the Thomas-Reiche-Kuhn sum rule of 0.76+-0.10. No evidence was found that would indicate an A-dependence for the enhancement factor. From event-by-event records of observed photoneutron multiplicities it was also possible to determine the mean number of photoneutrons, antiν, for each photon energy and the widths W of the multiplicities distributions. From these measurements one also obtains the cross section for the formation of a compound nucleus state excited with the full energy of the absorbed photon [fr

Elastic scattering and total cross section at very high energies

International Nuclear Information System (INIS)

Castaldi, R.; Sanguinetti, G.

1985-01-01

The aim of this review is to summarize the recent progress in the field of elastic scattering and total cross section in this new energy domain. In Section 2 a survey of the experimental situation is outlined. The most significant data are presented, with emphasis on the interpretation, not the specific details or technicalities. This section is therefore intended to give a self-contained look at the field, especially for the nonspecialist. In Section 3, hadron scattering at high energy is described in an impact parameter picture, which provides a model-independent intuitive geometrical representation. The diffractive character of elastic scattering, seen as the shadow of inelastic absorption, is presented as a consequence of unitarity in the s-channel. Spins are neglected throughout this review, inasmuch as the asymptotic behavior in the very high-energy limit is the main concern here. In Section 4 some relevant theorems are recalled on the limiting behavior of hadron-scattering amplitudes at infinite energy. There is also a brief discussion on how asymptotically rising total cross sections imply scaling properties in the elastic differential cross sections. A quick survey of eikonal models is presented and their predictions are compared with ISR and SPS Collider data

Mediating effects of self-stigma on the relationship between perceived stigma and psychosocial outcomes among psychiatric outpatients: findings from a cross-sectional survey in Singapore

OpenAIRE

Picco, Louisa; Lau, Ying Wen; Pang, Shirlene; Abdin, Edimansyah; Vaingankar, Janhavi Ajit; Chong, Siow Ann; Subramaniam, Mythily

2017-01-01

Objectives To examine whether self-stigma mediates the relationship between perceived stigma and quality of life, self-esteem and general functioning among outpatients with depression, schizophrenia, anxiety and obsessive-compulsive disorder (OCD). Design Cross-sectional survey. Setting Outpatient clinics at a tertiary psychiatric hospital in Singapore. Participants 280 outpatients with a primary clinical diagnosis of either schizophrenia, depression, anxiety or OCD. Methods Data were collect...

Search for ψ(2S) production in e+e- annihilations at 4.03GeV

International Nuclear Information System (INIS)

Bai, J.Z.; Bian, J.G.; Chai, Z.W.; Chen, G.P.; Chen, J.C.; Chen, Y.; Chen, Y.B.; Chen, Y.Q.; Cheng, B.S.; Cui, X.Z.; Ding, H.L.; Ding, L.Y.; Dong, L.Y.; Du, Z.Z.; Feng, S.; Gao, C.S.; Gao, M.L.; Gao, S.Q.; Gu, J.H.; Gu, S.D.; Gu, W.X.; Gu, Y.F.; Guo, Y.N.; Han, S.W.; Han, Y.; He, J.; He, J.T.; Hu, G.Y.; Hu, H.M.; Hu, J.L.; Hu, Q.H.; Hu, T.; Hu, X.Q.; Huang, J.D.; Huang, Y.Z.; Jiang, C.H.; Jin, Y.; Ke, Z.J.; Lai, Y.F.; Lang, P.F.; Li, C.G.; Li, D.; Li, H.B.; Li, J.; Li, P.Q.; Li, R.B.; Li, W.; Li, W.D.; Li, W.G.; Li, X.H.; Li, X.N.; Liu, H.M.; Liu, J.; Liu, J.H.; Liu, R.G.; Liu, Y.; Lu, F.; Lu, J.G.; Lu, J.Y.; Lu, L.C.; Luo, C.H.; Ma, A.M.; Ma, E.C.; Ma, J.M.; Mao, H.S.; Mao, Z.P.; Meng, X.C.; Nie, J.; Qi, N.D.; Qi, X.R.; Qiu, J.F.; Qu, Y.H.; Que, Y.K.; Rong, G.; Shao, Y.Y.; Shen, B.W.; Shen, D.L.; Shen, H.; Shen, X.Y.; Sheng, H.Y.; Shi, H.Z.; Song, X.F.; Sun, F.; Sun, H.S.; Tang, S.Q.; Tong, G.L.; Wang, F.; Wang, L.S.; Wang, L.Z.; Wang, M.; Wang, M.; Wang, P.; Wang, P.L.; Wang, S.M.; Wang, T.J.; Wang, Y.Y.; Wei, C.L.; Wu, Y.G.; Xi, D.M.; Xia, X.M.; Xie, P.P.; Xie, Y.; Xie, Y.H.; Xiong, W.J.; Xu, C.C.; Xu, G.F.; Xue, S.T.; Yan, J.; Yan, W.G.; Yang, C.M.; Yang, C.Y.; Yang, J.; Yang, X.F.; Ye, M.H.; Yi, K.; Yu, C.S.; Yu, C.X.; Yu, Z.Q.; Yu, Z.T.; Yuan, C.Z.; Yuan, Y.; Zhang, B.Y.; Zhang, C.C.; Zhang, D.H.; Zhang, D.; Zhang, H.L.; Zhang, J.; Zhang, J.L.; Zhang, J.W.; Zhang, L.S.; Zhang, Q.J.; Zhang, S.Q.; Zhang, Y.; Zhang, Y.Y.; Zhao, D.X.; Zhao, H.W.; Zhao, J.W.; Zhao, M.; Zhao, W.R.; Zheng, J.P.; Zheng, L.S.; Zheng, Z.P.; Zhou, G.P.; Zhou, H.S.; Zhou, L.; Zhu, Q.M.; Zhu, Y.C.; Zhu, Y.S.; Zhuang, B.A.; Hitlin, D.G.; Kelsey, M.H.; Oyang, J.; Panetta, J.; Porter, F.; Weaver, M.; Chen, J.; Malchow, R.; Toki, W.; Yang, W.; Yu, Y.H.

1998-01-01

A search is performed for the production of the ψ(2S) in e + e - annihilation at a center-of-mass energy of 4.03 GeV using the BES detector operated at the Beijing Electron Positron Collider (BEPC). The kinematic features of the reconstructed ψ(2S) signal are consistent with its being produced only in association with an energetic photon resulting from initial state radiation (ISR). Limits are placed on ψ(2S) production from the decay of unknown charmonia or metastable hybrids that might be produced in e + e - annihilations at 4.03GeV. Under the assumption that the observed cross section for ψ(2S) production is due entirely to ISR, the partial width Γ ee of the ψ(2S) is measured to be 2.07±0.32keV. copyright 1998 The American Physical Society

Predictors of breast feeding self-efficacy in the immediate postpartum period: A cross-sectional study.

Science.gov (United States)

Yang, Xiao; Gao, Ling-Ling; Ip, Wan-Yim; Sally Chan, Wai Chi

2016-10-01

to examine breast feeding self-efficacy and identify its predictors among mainland Chinese mothers in the early postpartum period. a cross-sectional descriptive questionnaire survey was conducted in a regional teaching hospital with childbirth rate over 3000 per year at Guangzhou, China from April 1 to July 14, 2014. a total of 571 Chinese mothers who were within 72-96hours post partum were recruited consecutively to the study. data were collected by the Chinese version of the Breastfeeding Self-efficacy Scale-Short Form (BSES-SF), the Network Support for Breastfeeding Scale (NSBS) and a socio-demographic data sheet. a total of 640 eligible women was approached and 571 mothers completed the study with the response rate of 89%. Mothers reported moderate level of breast feeding self-efficacy in the immediate postpartum period. The best-fit regression analysis revealed six variables that explained 43.9% of the variance in breast feeding self-efficacy in the immediate postpartum period. They were intention of breast feeding, support from husband, support from nurses/midwives, attending antenatal breast feeding classes, time from childbirth to initiate breast feeding and previous breast feeding experience. this study found six predictors of breast feeding self-efficacy in the immediate postpartum period. In order to increase maternal breast feeding self-efficacy level, a more women-centred approach is recommended. Mothers and fathers should be facilitated to attend antenatal classes on breast feeding. New mother' husband could be encouraged in supporting breast feeding. Nurses and midwives could encourage new mothers to initiate breast feeding as soon as possible. Further work to promote early mother-infant contact post birth, such as via skin to skin contact should also be facilitated where possible. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quality of life, self-stigma, and hope in schizophrenia spectrum disorders: a cross-sectional study.

Science.gov (United States)

Vrbova, Kristyna; Prasko, Jan; Ociskova, Marie; Kamaradova, Dana; Marackova, Marketa; Holubova, Michaela; Grambal, Ales; Slepecky, Milos; Latalova, Klara

2017-01-01

The aim of this study was to explore the quality of life, self-stigma, personality traits, and hope in patients with schizophrenia spectrum disorders. A total of 52 outpatients participated in this cross-sectional study. The attending psychiatrist assessed each patient with Mini International Neuropsychiatric Interview (MINI). The patients then completed Quality of Life Satisfaction and Enjoyment Questionnaire (Q-LES-Q), Internalized Stigma of Mental Illness (ISMI) Scale, Temperament and Character Inventory - Revised (TCI-R), Adult Dispositional Hope Scale (ADHS), Drug Attitude Inventory 10 (DAI-10), and Liebowitz Social Anxiety Scale (LSAS)-Self-report. The psychiatrist evaluated Clinical Global Impression Severity - the objective version (objCGI-S), and the patients completed the Clinical Global Impression Severity - the subjective version (subjCGI-S). Each participant also completed Beck Depression Inventory-II (BDI-II), and Beck Anxiety Inventory (BAI). The quality of life was significantly higher in employed patients and individuals with higher hope, self-directedness (SD), and persistence (PS). The quality of life was lower among patients with higher number of psychiatric hospitalizations, those with higher severity of the disorder, and individuals who were taking higher doses of antipsychotics. Patients with more pronounced symptoms of depression, anxiety, and social anxiety had a lower quality of life. Finally, the quality of life was lower among individuals with higher harm avoidance (HA) and self-stigmatization (ISMI). Backward stepwise regression was applied to identify the most significant factors connected to self-stigma. The regression analysis showed that occupation, level of depression (BDI-II), attitude to using medication (DAI-10), social anxiety (LSAS), and antipsychotic index were the most relevant factors associated with lower quality of life. Detection of the quality of life in the context of personality traits, hope, self-stigma, and

Self-stigma and quality of life in patients with depressive disorder: a cross-sectional study

Directory of Open Access Journals (Sweden)

Holubova M

2016-10-01

Full Text Available Michaela Holubova,1,2 Jan Prasko,1 Marie Ociskova,1 Marketa Marackova,1 Ales Grambal,1 Milos Slepecky3 1Department of Psychiatry, Faculty of Medicine and Dentistry, Palacky University Olomouc, University Hospital Olomouc, Olomouc, 2Department of Psychiatry, Hospital Liberec, Liberec, Czech Republic; 3Department of Psychology Sciences, Faculty of Social Science and Health Care, Constantine the Philosopher University, Nitra, Slovak Republic Background: Self-stigma is a maladaptive psychosocial phenomenon that can affect many areas of patients’ lives and have a negative impact on their quality of life (QoL. This study explored the association between self-stigma, QoL, demographic data, and the severity of symptoms in patients with depressive disorder. Patients and methods: Patients who met the International Classification of Diseases, 10th revision, research criteria for depressive disorder were enrolled in this cross-sectional study. All outpatients completed the following measurements: the Quality of Life Enjoyment and Satisfaction Questionnaire, the Internalized Stigma of Mental Illness Scale, demographic questionnaire, and the objective and subjective Clinical Global Impression-Severity scales that measure the severity of disorder. A total of 81 depressive disorder patients (with persistent affective disorder – dysthymia, major depressive disorder, or recurrent depressive disorder and 43 healthy controls participated in this study. Results: Compared with the healthy control group, a lower QoL was observed in patients with depressive disorder. The level of self-stigma correlated positively with total symptom severity score and negatively with QoL. Multiple regression analysis revealed that the overall rating of objective symptom severity and score of self-stigma were significantly associated with QoL. Conclusion: This study suggests a lower QoL in patients with depressive disorder in comparison with healthy controls and a negative impact of

Granular effect on the effective cross sections in the HTGR type reactors

International Nuclear Information System (INIS)

Almeida Ferreira, A.C. de.

1975-01-01

Effective cross section of bars for HTGR is studied from the point of view of heterogeneity. Microscopical heterogeneity due to grains is represented by a self-shielding factor, which is well determined [pt

Electron-impact cross sections of Ne

International Nuclear Information System (INIS)

Tsurubuchi, S.; Arakawa, K.; Kinokuni, S.; Motohashi, K.

2000-01-01

Electron-impact absolute emission cross sections were measured for the 3p→3s transitions of Ne. Excitation functions of the 3s→2p first resonance lines were measured in the energy range from the threshold to 1000 eV by a polarization-free optical method and relative cross sections were normalized to the absolute values, (41.0±5.4)x10 -19 cm 2 for the 73.6 nm line and (7.1±1.0)x10 -19 cm 2 for the 74.4 nm line, which were determined at 500 eV. The integrated level-excitation cross sections of Suzuki et al for the 1s 2 and 1s 4 levels were combined with the corresponding 3p→3s cascade cross sections obtained in this paper to give absolute emission cross sections for the resonance lines. The level-excitation cross sections of the 1s 2 and 1s 4 states in Paschen notation were determined from the threshold to 1000 eV by subtracting 3p→3s cascade cross sections from the corresponding 3s→2p emission cross sections of the resonance lines. A large cascade contribution is found in the emission cross section of the resonance lines. It is 28.5% for the 73.6 nm line and 49.6% for the 74.4 nm line at 40 eV, and 17.0 and 61.8%, respectively, at 300 eV. (author)

Neutron cross sections: Book of curves

International Nuclear Information System (INIS)

McLane, V.; Dunford, C.L.; Rose, P.F.

1988-01-01

Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs

Evaluated cross section libraries

International Nuclear Information System (INIS)

Maqurno, B.A.

1976-01-01

The dosimetry tape (ENDF/B-IV tape 412) was issued in a general CSEWG distribution, August 1974. The pointwise cross section data file was tested with specified reference spectra. A group averaged cross section data file (620 groups based on tape 412) was tested with the above spectra and the results are presented in this report

FCXSEC: multigroup cross-section libraries for nuclear fuel cycle shielding calculations

International Nuclear Information System (INIS)

Ford, W.E. III; Webster, C.C.; Diggs, B.R.; Pevey, R.E.; Croff, A.G.

1980-05-01

Starting with the pseudo-composition-independent VITAMIN-C cross-sectin library, composition-dependent fine-(171n-36γ) and broad-group (22n-21γ) self-shielded AMPX master, broad-group microscopic ANISN-formatted, and broad-group macroscopic ANISN-formatted cross-section libraries were generated to be used for nuclear fuel cycle shielding calculations. The specifications for the data and the procedure used to prepare the libraries are described

Oral health self-perception in quilombola communities in Rio Grande do Sul: a cross-sectional exploratory study.

Science.gov (United States)

Bidinotto, Augusto Bacelo; D'Ávila, Otávio Pereira; Martins, Aline Blaya; Hugo, Fernando Neves; Neutzling, Marilda Borges; Bairros, Fernanda de Souza; Hilgert, Juliana Balbinot

2017-01-01

There's a shortage of evidence on the oral health of quilombolas. This study aims to describe oral health self-perception, as well as to verify its associated factors in quilombola communities in the state of Rio Grande do Sul. The data for this cross-sectional health survey were collected by application of a questionnaire. Since this study was part of a survey on nutritional security, the probabilistic cluster sample was estimated for the outcome of nutritional insecurity, comprising 583 individuals across quilombola communities in Rio Grande do Sul. The association between the outcome of negative oral health self-perception and sociodemographic, general health, and oral health variables was measured by prevalence ratios obtained through Poisson regressions with robust variance and 95% confidence intervals. Negative self-rated oral health was reported by 313 (53.1%) of the individuals. Satisfaction with chewing ability and satisfaction with oral appearance were associated with a higher prevalence of negative perception of oral health, while there was no association between the outcome and number of teeth. Use of alcohol had a borderline association with the outcome. Satisfaction with appearance and chewing ability are factors associated with oral-health self-perception of the quilombolas in Rio Grande do Sul.

Neutron mean annihilation time and inverse of the mean annihilation rate in nuclear reactor

International Nuclear Information System (INIS)

Hayashi, Masatoshi

1999-01-01

There is a dogma in nuclear reactor theory that in a critical reactor the mean annihilation time of neutron is equal to the mean generation time. The author insists that this is a dogma from the basic reexamination of the mean annihilation time of neutron. There are two kinds of neutrons, one participating in chain reactions and the other not participating in chain reactions. The mean annihilation time of neutron is the mean time of the time to annihilation of all neutrons generated in the reactor. The 'prompt neutron life' as a dynamic characteristic parameter proper to nuclear reactor can not be understood as the mean time of neutron to annihilation. The author explains the logic quantitatively with two kinds of nuclear reactors, a bare reactor and an infinite reactor, for which two different mean neutron annihilation times can be defined. Thus, (1) the inverse of the annihilation rate can not simply be considered as the mean annihilation time, (2) the mean annihilation time of a critical reactor is not necessarily equal to the mean generation time, and (3) the prompt neutron life used as a dynamic characteristic parameter of a nuclear reactor can not be understood as the mean time of neutron to annihilation. (M.M.)

Review of indirect detection of dark matter with neutrinos

Science.gov (United States)

Danninger, Matthias

2017-09-01

Dark Matter could be detected indirectly through the observation of neutrinos produced in dark matter self-annihilations or decays. Searches for such neutrino signals have resulted in stringent constraints on the dark matter self-annihilation cross section and the scattering cross section with matter. In recent years these searches have made significant progress in sensitivity through new search methodologies, new detection channels, and through the availability of rich datasets from neutrino telescopes and detectors, like IceCube, ANTARES, Super-Kamiokande, etc. We review recent experimental results and put them in context with respect to other direct and indirect dark matter searches. We also discuss prospects for discoveries at current and next generation neutrino detectors.

Recent validation experience with multigroup cross-section libraries and scale

International Nuclear Information System (INIS)

Bowman, S.M.; Wright, R.Q.; DeHart, M.D.; Parks, C.V.; Petrie, L.M.

1995-01-01

This paper will discuss the results obtained and lessons learned from an extensive validation of new ENDF/B-V and ENDF/B-VI multigroup cross-section libraries using analyses of critical experiments. The KENO V. a Monte Carlo code in version 4.3 of the SCALE computer code system was used to perform the critical benchmark calculations via the automated SCALE sequence CSAS25. The cross-section data were processed by the SCALE automated problem-dependent resonance-processing procedure included in this sequence. Prior to calling KENO V.a, CSAS25 accesses BONAMI to perform resonance self-shielding for nuclides with Bondarenko factors and NITAWL-II to process nuclides with resonance parameter data via the Nordheim Integral Treatment

Self-efficacy and Associated Factors in Patients With Temporary Ostomies: A Cross-sectional Survey.

Science.gov (United States)

Su, Xi; Qin, Fang; Zhen, Li; Ye, Xinmei; Kuang, Yinyi; Zhu, Mulan; Yin, Xuexia; Wang, Huizhen

To examine stoma self-efficacy (SE) and its association with health-related quality of life (HRQOL) and social support in patients with temporary ostomies. Convenience sampling was used to recruit 150 patients from 5 hospitals in Guangdong province, China, who had been living with a temporary ostomy for at least 1 month. Cross-sectional survey. Respondents completed a questionnaire that included ostomy-related sociodemographic and clinical data, and Chinese language versions of several validated instruments, the Stoma Self-efficacy Scale (C-SSES), City of Hope-Quality of Life-Ostomy Questionnaire (C-COH-QOL-OQ), and Perceived Social Support Scale (C-PSSS). Of the 150 questionnaires distributed, 122 (81.3%) were returned, and 111 (74%) had sufficiently complete responses to be included in the final analysis. The average score from the C-SSES was 78.55 ± 14.72 (mean ± standard deviation) for total stoma SE; 85.6% of respondents showed low or moderate self-efficacy related to ostomy care. The scores from the C-SSES were 39.36 ± 7.72 for stoma care SE and 23.33 ± 6.69 for social SE. Stoma care SE was significantly associated with HRQOL domains, psychological well-being (B = 2.09, P ostomies reported low or moderate levels of SE, suggesting the need to focus on HRQOL aspects of psychological and social well-being, as well as social support. We hypothesize that interaction with other ostomy patients, especially those with long-term enterostomy experience or those trained through ostomy organizations, may improve stoma SE.

Nuclear Forensics and Radiochemistry: Cross Sections

Energy Technology Data Exchange (ETDEWEB)

Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-11-08

The neutron activation of components in a nuclear device can provide useful signatures of weapon design or sophistication. This lecture will cover some of the basics of neutron reaction cross sections. Nuclear reactor cross sections will also be presented to illustrate the complexity of convolving neutron energy spectra with nuclear excitation functions to calculate useful effective reactor cross sections. Deficiencies in the nuclear database will be discussed along with tools available at Los Alamos to provide new neutron cross section data.

Differential Top Cross-section Measurements

CERN Document Server

Fenton, Michael James; The ATLAS collaboration

2017-01-01

The top quark is the heaviest known fundamental particle. The measurement of the differential top-quark pair production cross-section provides a stringent test of advanced perturbative QCD calculations. The ATLAS collaboration has performed detailed measurements of those differential cross sections at a centre-of-mass energy of 13 TeV. This talk focuses on differential cross-section measurements in the lepton+jets final state, including using boosted top quarks to probe our understanding of top quark production in the TeV regime.

Search for elastic nondiagonal lepton-pair production in e+e- annihilation at √s =29 GeV

International Nuclear Information System (INIS)

Gomez-Cadenas, J.J.; Heusch, C.A.; Abrams, G.; Adolphsen, C.E.; Akerlof, C.; Alexander, J.P.; Alvarez, M.; Amidei, D.; Baden, A.R.; Ballam, J.; Barish, B.C.; Barklow, T.; Barnett, B.A.; Bartelt, J.; Blockus, D.; Bonvicini, G.; Boyarski, A.; Boyer, J.; Brabson, B.; Breakstone, A.; Brom, J.M.; Bulos, F.; Burchat, P.R.; Burke, D.L.; Butler, F.; Calvino, F.; Cence, R.J.; Chapman, J.; Cords, D.; Coupal, D.P.; DeStaebler, H.C.; Dorfan, D.E.; Dorfan, J.M.; Drell, P.S.; Feldman, G.J.; Fernandez, E.; Field, R.C.; Ford, W.T.; Fordham, C.; Frey, R.; Fujino, D.; Gan, K.K.; Gidal, G.; Gladney, L.; Glanzman, T.; Gold, M.S.; Goldhaber, G.; Golding, L.; Green, A.; Grosse-Wiesmann, P.; Haggerty, J.; Hanson, G.; Harr, R.; Harris, F.A.; Hawkes, C.M.; Hayes, K.; Herrup, D.; Himel, T.; Hoenk, M.; Hollebeek, R.J.; Hutchinson, D.; Hylen, J.; Innes, W.R.; Jaffre, M.; Jaros, J.A.; Juricic, I.; Kadyk, J.A.; Karlen, D.; Kent, J.; Klein, S.R.; Koide, A.; Koska, W.; Kozanecki, W.; Lankford, A.J.; Larsen, R.R.; LeClaire, B.W.; Levi, M.E.; Li, Z.; Litke, A.M.; Lockyer, N.S.; Lueth, V.; Matteuzzi, C.; Matthews, J.A.J.; Meyer, D.I.; Milliken, B.D.; Moffeit, K.C.; Mueller, L.; Nash, J.; Nelson, M.E.; Nitz, D.; Ogren, H.; Ong, R.A.; O'Shaughnessy, K.F.; Parker, S.I.; Peck, C.; Petersen, A.; Petradza, M.; Porter, F.C.; Rankin, P.; Richter, B.; Riles, K.; Rowson, P.C.; Rust, D.R.; Sadrozinski, H.F.W.; Schaad, T.; Schalk, T.L.; Schellman, H.; Schmidke, W.B.; Schwarz, A.S.; Seiden, A.; Sheldon, P.D.; Smith, J.G.; Snyder, A.; Soderstrom, E.; Stoker, D.P.; Stroynowski, R.; Thun, R.; Trilling, G.H.; Tschirhart, R.; de la Vaissiere, C.; Van Kooten, R.; Veltman, H.; Voruganti, P.; Wagner, S.R.; Weber, P.; Weinstein, A.J.; Weir, A.J.; Weisz, S.; White, S.L.; Wicklund, E.; Wood, D.R.; Wu, D.Y.; Yelton, J.M.

1991-01-01

We have searched for the annihilation of e + e- into the exclusive channels e ± τ minus-plus and μ ± τ minus-plus at √s =29 GeV, using 226 and 133 pb -1 , respectively, of data taken with the Mark II detector at the SLAC storage ring PEP. The resulting candidate sample is compatible with the expected background from τ pair production. Our analysis yields 95%-C.L. cross-section limits of σ eτ /σ μμ -3 and σ μτ /σ μμ -3 , where σ μμ is the QED cross section for production of a lepton pair. This is the first high-Q 2 test of lepton-flavor conservation involving τ leptons

Feasibility of supervised self-testing using an oral fluid-based HIV rapid testing method: a cross-sectional, mixed method study among pregnant women in rural India

OpenAIRE

Sarkar, Archana; Mburu, Gitau; Shivkumar, Poonam Varma; Sharma, Pankhuri; Campbell, Fiona; Behera, Jagannath; Dargan, Ritu; Mishra, Surendra Kumar; Mehra, Sunil

2016-01-01

Introduction: HIV self-testing can increase coverage of essential HIV services. This study aimed to establish the acceptability, concordance and feasibility of supervised HIV self-testing among pregnant women in rural India. Methods: A cross-sectional, mixed methods study was conducted among 202 consenting pregnant women in a rural Indian hospital between August 2014 and January 2015. Participants were provided with instructions on how to self-test using OraQuick® HIV antibody test, and subse...

Measurements of absolute M-subshell X-ray production cross sections of Th by electron impact

Energy Technology Data Exchange (ETDEWEB)

Moy, A., E-mail: aurelien.moy@cea.fr [GM, CNRS, Université de Montpellier II, Place E. Bataillon, F-34095 Montpellier (France); CEA, DEN, DTEC, SGCS, LMAC, F-30207 Bagnols-sur-Cèze (France); Merlet, C. [GM, CNRS, Université de Montpellier II, Place E. Bataillon, F-34095 Montpellier (France); Dugne, O. [CEA, DEN, DTEC, SGCS, LMAC, F-30207 Bagnols-sur-Cèze (France)

2014-08-31

Highlights: • The M X-ray production cross sections of Th were measured by electron impact. • The M-subshell ionization cross sections of Th were determined from 3 to 38 keV. • Theoretical ionization cross-sections are in agreement with our experimental results. - Abstract: Measurements of absolute M-subshell X-ray production cross sections for element Th were made by electron impact for energies ranging from the ionization threshold up to 38 keV. Experimental data were obtained by measuring the X-ray intensity emitted from ultrathin Th films deposited onto self-supporting C backing films. The measurements were conducted with an electron microprobe using high-resolution wavelength dispersive spectrometers. Recorded intensities were converted into absolute X-ray production cross sections by means of atomic data and estimation of the number of primary electrons, target thickness, and detector efficiency. Our experimental X-ray production cross sections, the first to be reported for the M subshells of Th, are compared with X-ray production cross sections calculated with the mean of ionization cross sections obtained from the distorted-wave Born approximation. The Mα X-ray production cross section calculated is in excellent agreement with the measurements, allowing future use for standardless quantification in electron probe microanalysis.

Activation cross section data file, (1)

International Nuclear Information System (INIS)

Yamamuro, Nobuhiro; Iijima, Shungo.

1989-09-01

To evaluate the radioisotope productions due to the neutron irradiation in fission of fusion reactors, the data for the activation cross sections ought to be provided. It is planning to file more than 2000 activation cross sections at final. In the current year, the neutron cross sections for 14 elements from Ni to W have been calculated and evaluated in the energy range 10 -5 to 20 MeV. The calculations with a simplified-input nuclear cross section calculation system SINCROS were described, and another method of evaluation which is consistent with the JENDL-3 were also mentioned. The results of cross section calculation are in good agreement with experimental data and they were stored in the file 8, 9 and 10 of ENDF/B format. (author)

Self-Medication Practices with Antibiotics among Tertiary Level Students in Accra, Ghana: A Cross-Sectional Study

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Patrick Nartey

2012-10-01

Full Text Available The study was carried out to estimate the prevalence of self-medication with antibiotics among tertiary level students in Accra (Ghana and evaluate factors associated with the practice. This was a descriptive cross-sectional study and involved face-to-face interviews of 600 respondents selected by convenient sampling. Prevalence of self medication was 70% (95% CI: 66.3–73.7, and the practice was significantly lower among medically inclined students (OR: 0.2, 95% CI: 0.1–0.4, p < 0.001. Among the respondents who practiced self medication, the most common frequency of antibiotic usage was at intervals of one month (30%, 95% CI: 25.6–34.4%, and the most common antibiotic used was amoxacillin (23.9%, 95% CI: 21.0–26.8%. Treatment failure were reported by 35% (95% CI: 30.5–39.6% of the respondents, and the main reasons cited for self medication were that, it was less expensive compared to medical care in the hospital and  secondly, medical care in hospitals were associated with long delays. Forty nine percent (95% CI: 44.2–53.8% of the respondents had poor knowledge about the health implications of irrational use of antibiotics, and 46% (95% CI: 41.2–50.8% did not comply with the completion of the full course of antibiotics. Self medication among tertiary students in Accra is an important public health problem and this may reflect the situation among tertiary students in the whole of Ghana.

Self-interacting asymmetric dark matter coupled to a light massive dark photon

International Nuclear Information System (INIS)

Petraki, Kalliopi; Pearce, Lauren; Kusenko, Alexander

2014-01-01

Dark matter (DM) with sizeable self-interactions mediated by a light species offers a compelling explanation of the observed galactic substructure; furthermore, the direct coupling between DM and a light particle contributes to the DM annihilation in the early universe. If the DM abundance is due to a dark particle-antiparticle asymmetry, the DM annihilation cross-section can be arbitrarily large, and the coupling of DM to the light species can be significant. We consider the case of asymmetric DM interacting via a light (but not necessarily massless) Abelian gauge vector boson, a dark photon. In the massless dark photon limit, gauge invariance mandates that DM be multicomponent, consisting of positive and negative dark ions of different species which partially bind in neutral dark atoms. We argue that a similar conclusion holds for light dark photons; in particular, we establish that the multi-component and atomic character of DM persists in much of the parameter space where the dark photon is sufficiently light to mediate sizeable DM self-interactions. We discuss the cosmological sequence of events in this scenario, including the dark asymmetry generation, the freeze-out of annihilations, the dark recombination and the phase transition which gives mass to the dark photon. We estimate the effect of self-interactions in DM haloes, taking into account this cosmological history. We place constraints based on the observed ellipticity of large haloes, and identify the regimes where DM self-scattering can affect the dynamics of smaller haloes, bringing theory in better agreement with observations. Moreover, we estimate the cosmological abundance of dark photons in various regimes, and derive pertinent bounds

Calculation of self-shielding factors for cross-sections in the unresolved resonance region using the GRUCON applied program package

International Nuclear Information System (INIS)

Sinitsa, V.V.

1984-11-01

The author gives a scheme for the calculation of the self-shielding factors in the unresolved resonance region using the GRUCON applied program package. This package is especially created to be used in the conversion of evaluated neutron cross-section data, as available in existing data libraries, into multigroup microscopic constants. A detailed description of the formulae and algorithms used in the programs is given. Some typical examples of calculation are considered and the results are compared with those of other authors. The calculation accuracy is better than 2%

Sex Partnership and Self-Efficacy Influence Depression in Chinese Transgender Women: A Cross-Sectional Study.

Science.gov (United States)

Yang, Xiaoshi; Wang, Lie; Hao, Chun; Gu, Yuan; Song, Wei; Wang, Jian; Chang, Margaret M; Zhao, Qun

2015-01-01

Transgender women often suffer from transition-related discrimination and loss of social support due to their gender transition, which may pose considerable psychological challenges and may lead to a high prevalence of depression in this population. Increased self-efficacy may combat the adverse effects of gender transition on depression. However, few available studies have investigated the protective effect of self-efficacy on depression among transgender women, and there is a scarcity of research describing the mental health of Chinese transgender women. This study aims to describe the prevalence of depression among Chinese transgender women and to explore the associated factors. A cross-sectional study was conducted in Shenyang, Liaoning Province of China by convenience sampling from January 2014 to July 2014. Two hundred and nine Chinese transgender women were interviewed face-to-face with questionnaires that covered topics including the Zung Self-Rating Depression Scale (SDS), demographic characteristics, transition status, sex partnership, perceived transgender-related discrimination, the Multidimensional Scale of Perceived Social Support (MSPSS) and the adapted General Self-efficacy Scale (GSES). A hierarchical multiple regression analysis was performed to explore the factors associated with SDS scores. The prevalence of depression among transgender women was 45.35%. Transgender women with regular partners or casual partners exhibited higher SDS scores than those without regular partners or casual partners. Regression analyses showed that sex partnership explained most (16.6%) of the total variance in depression scores. Self-efficacy was negatively associated with depression. Chinese transgender women experienced high levels of depression. Depression was best predicted by whether transgender women had a regular partner or a casual partner rather than transgender-related discrimination and transition status. Moreover, self-efficacy had positive effects on

Sex Partnership and Self-Efficacy Influence Depression in Chinese Transgender Women: A Cross-Sectional Study.

Directory of Open Access Journals (Sweden)

Xiaoshi Yang

Full Text Available Transgender women often suffer from transition-related discrimination and loss of social support due to their gender transition, which may pose considerable psychological challenges and may lead to a high prevalence of depression in this population. Increased self-efficacy may combat the adverse effects of gender transition on depression. However, few available studies have investigated the protective effect of self-efficacy on depression among transgender women, and there is a scarcity of research describing the mental health of Chinese transgender women. This study aims to describe the prevalence of depression among Chinese transgender women and to explore the associated factors.A cross-sectional study was conducted in Shenyang, Liaoning Province of China by convenience sampling from January 2014 to July 2014. Two hundred and nine Chinese transgender women were interviewed face-to-face with questionnaires that covered topics including the Zung Self-Rating Depression Scale (SDS, demographic characteristics, transition status, sex partnership, perceived transgender-related discrimination, the Multidimensional Scale of Perceived Social Support (MSPSS and the adapted General Self-efficacy Scale (GSES. A hierarchical multiple regression analysis was performed to explore the factors associated with SDS scores.The prevalence of depression among transgender women was 45.35%. Transgender women with regular partners or casual partners exhibited higher SDS scores than those without regular partners or casual partners. Regression analyses showed that sex partnership explained most (16.6% of the total variance in depression scores. Self-efficacy was negatively associated with depression.Chinese transgender women experienced high levels of depression. Depression was best predicted by whether transgender women had a regular partner or a casual partner rather than transgender-related discrimination and transition status. Moreover, self-efficacy had positive

Positron annihilation lifetime spectroscopy (PALS) as a characterization technique for nanostructured self-assembled amphiphile systems.

Science.gov (United States)

Dong, Aurelia W; Pascual-Izarra, Carlos; Pas, Steven J; Hill, Anita J; Boyd, Ben J; Drummond, Calum J

2009-01-08

Positron annihilation lifetime spectroscopy (PALS) has potential as a novel rapid characterization method for self-assembly amphiphile systems; however, a lack of systematic correlation of PALS parameters with structural attributes has limited its more widespread application. In this study, using the well-characterized phytantriol/water and the phytantriol/vitamin E acetate/water self-assembly amphiphile systems, the impact of systematic structural changes controlled by changes in composition and temperature on PALS parameters has been studied. The PALS parameters (orthopositronium (oPs) lifetime and intensity signatures) were shown to be sensitive to the molecular packing and mobility of the self-assembled lipid molecules in various lyotropic liquid crystalline phases, enabling differentiation between liquid crystalline structures. The oPs lifetime, related to the molecular packing and mobility, is correlated with rheological properties of the individual mesophases. The oPs lifetime links the lipid chain packing and mobility in the various mesophases to resultant macroscopic properties, such as permeability, which is critical for the use of these mesophase structures as diffusion-controlled release matrices for active liposoluble compounds.

The Mediating Effect of Regulatory Emotional Self-Efficacy on the Association between Self-Esteem and School Bullying in Middle School Students: A Cross-Sectional Study

Directory of Open Access Journals (Sweden)

Xiaoqin Wang

2018-05-01

Full Text Available School bullying is negatively associated with self-esteem, but psychological mediators of bullying have yet to be clarified. We examined regulatory emotional self-efficacy (RESE as a possible mediator in the association between self-esteem and school bullying. A cross-sectional study of 995 adolescents was conducted in two middle schools of Xi’an. All of the participants completed the Chinese version of the School Bullying Experience Questionnaire (C-SBEQ, Self-Esteem Scale (SES, and Regulatory Emotional Self-Efficacy Scale (RESE. Descriptive statistics analysis, the bias corrected percentile Bootstrap CI method, and structural equation modelling were used to analyze the data. The results showed that 418 students (42.0% reported that they were involved in school bullying in the past year. Self-esteem was negatively associated with school bullying (total effect: β = −0.275, 95% CI = −0.381–−0.034, and RESE mediated the association between self-esteem and school bullying (indirect effect: β = −0.136, 95% CI = −0.245–−0.037. Furthermore, self-esteem had an indirect effect through perceived self-efficacy in managing negative affect, while self-esteem had no indirect effect through self-efficacy in the expression of positive affect. The present study suggests that school authorities and the related education departments should not only focus on improving students’ self-esteem, but should also pay more attention to students’ RESE, in order to mitigate, and potentially reduce, the occurrence of bullying.

The Mediating Effect of Regulatory Emotional Self-Efficacy on the Association between Self-Esteem and School Bullying in Middle School Students: A Cross-Sectional Study.

Science.gov (United States)

Wang, Xiaoqin; Zhang, Yue; Hui, Zhaozhao; Bai, Wanyue; Terry, Paul D; Ma, Mei; Li, Yang; Cheng, Li; Gu, Wei; Wang, Mingxu

2018-05-15

School bullying is negatively associated with self-esteem, but psychological mediators of bullying have yet to be clarified. We examined regulatory emotional self-efficacy (RESE) as a possible mediator in the association between self-esteem and school bullying. A cross-sectional study of 995 adolescents was conducted in two middle schools of Xi'an. All of the participants completed the Chinese version of the School Bullying Experience Questionnaire (C-SBEQ), Self-Esteem Scale (SES), and Regulatory Emotional Self-Efficacy Scale (RESE). Descriptive statistics analysis, the bias corrected percentile Bootstrap CI method, and structural equation modelling were used to analyze the data. The results showed that 418 students (42.0%) reported that they were involved in school bullying in the past year. Self-esteem was negatively associated with school bullying (total effect: β = -0.275, 95% CI = -0.381⁻-0.034), and RESE mediated the association between self-esteem and school bullying (indirect effect: β = -0.136, 95% CI = -0.245⁻-0.037). Furthermore, self-esteem had an indirect effect through perceived self-efficacy in managing negative affect, while self-esteem had no indirect effect through self-efficacy in the expression of positive affect. The present study suggests that school authorities and the related education departments should not only focus on improving students' self-esteem, but should also pay more attention to students' RESE, in order to mitigate, and potentially reduce, the occurrence of bullying.

Utilization of cross-section covariance data in FBR core nuclear design and cross-section adjustment

International Nuclear Information System (INIS)

Ishikawa, Makoto

1994-01-01

In the core design of large fast breeder reactors (FBRs), it is essentially important to improve the prediction accuracy of nuclear characteristics from the viewpoint of both reducing cost and insuring reliability of the plant. The cross-section errors, that is, covariance data are one of the most dominant sources for the prediction uncertainty of the core parameters, therefore, quantitative evaluation of covariance data is indispensable for FBR core design. The first objective of the present paper is to introduce how the cross-section covariance data are utilized in the FBR core nuclear design works. The second is to delineate the cross-section adjustment study and its application to an FBR design, because this improved design method markedly enhances the needs and importance of the cross-section covariance data. (author)

Annihilation of antiprotons at rest in 3He and 4He

International Nuclear Information System (INIS)

Balestra, F.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Fava, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F.; Bendiscioli, G.; Rotondi, R.; Salvini, P.; Zenoni, A.; Batusov, Y.A.; Bunyatov, S.A.; Falomkin, I.V.; Nichitiu, F.; Pontecorvo, G.B.; Sapozhnikov, M.G.; Tretyak, V.I.; Guaraldo, C.; Maggiora, A.; Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M.; Breivik, F.O.; Jacobsen, T.; Sorensen, S.O.

1987-01-01

At LEAR of CERN the annihilation of antiprotons stopping in 3 He and 4 He filling a self shunted streamer chamber in magnetic field has been studied. The relative probabilities of π - production in anti p 3 He and anti p 4 He annihilation events have been obtained. The ratio between the anti p annihilation probability on the neutron and on the proton for 3 He and 4 He has been deduced to be about half the value obtained for 2 H in bubble chamber experiments. The analysis of the results shows this difference cannot be ascribed only to the pion final state interaction or to the shadow effect of the nucleons in the nuclei. 9 refs.; 2 figs

System THEMIS. Cross sections processing system from ENDF/B

Energy Technology Data Exchange (ETDEWEB)

Gonnord, J.

1983-09-01

The THEMIS system allowed to prepare a self punctual and multigroup library for codes solving the TRIPOLI-PROMETHEE transport equation, allowing comparisons with different methods and approximations. The contents of the THEMIS data base was fixed from its use by the PROMETHEE system (punctual Monte Carlo calculations, multigroup calculations, uncertainties analysis and sensitivity studies). The main characteristics of the THEMIS cross section processing system are briefly presented.

Burnout Subtypes and Absence of Self-Compassion in Primary Healthcare Professionals: A Cross-Sectional Study.

Science.gov (United States)

Montero-Marin, Jesus; Zubiaga, Fernando; Cereceda, Maria; Piva Demarzo, Marcelo Marcos; Trenc, Patricia; Garcia-Campayo, Javier

2016-01-01

Primary healthcare professionals report high levels of distress and burnout. A new model of burnout has been developed to differentiate three clinical subtypes: 'frenetic', 'underchallenged' and 'worn-out'. The aim of this study was to confirm the validity and reliability of the burnout subtype model in Spanish primary healthcare professionals, and to assess the explanatory power of the self-compassion construct as a possible protective factor. The study employed a cross-sectional design. A sample of n = 440 Spanish primary healthcare professionals (214 general practitioners, 184 nurses, 42 medical residents) completed the Burnout Clinical Subtype Questionnaire (BCSQ-36), the Maslach Burnout Inventory General Survey (MBI-GS), the Self-Compassion Scale (SCS), the Utrecht Work Engagement Scale (UWES) and the Positive and Negative Affect Schedule (PANAS). The factor structure of the BCSQ-36 was estimated using confirmatory factor analysis (CFA) by the unweighted least squares method from polychoric correlations. Internal consistency (R) was assessed by squaring the correlation between the latent true variable and the observed variables. The relationships between the BCSQ-36 and the other constructs were analysed using Spearman's r and multiple linear regression models. The structure of the BCSQ-36 fit the data well, with adequate CFA indices for all the burnout subtypes. Reliability was adequate for all the scales and sub-scales (R≥0.75). Self-judgement was the self-compassion factor that explained the frenetic subtype (Beta = 0.36; pUWES and PANAS. The typological definition of burnout through the BCSQ-36 showed good structure and appropriate internal consistence in Spanish primary healthcare professionals. The negative self-compassion dimensions seem to play a relevant role in explaining the burnout profiles in this population, and they should be considered when designing specific treatments and interventions tailored to the specific vulnerability of each subtype.

Relationship between perceived social support and self-care behavior in type 2 diabetics: A cross-sectional study.

Science.gov (United States)

Mohebi, Siamak; Parham, Mahmoud; Sharifirad, Gholamreza; Gharlipour, Zabihollah; Mohammadbeigi, Abolfazl; Rajati, Fatemeh

2018-01-01

Social support is one of the most effective factors on the diabetic self-care. This study aimed to assess social support and its relationship to self-care in type 2 diabetic patients in Qom, Iran. A cross-sectional study was conducted on 325 diabetics attending the Diabetes Mellitus Association. Patients who meet inclusion and exclusion criteria were selected using random sampling method. Data were collected by the Summary of Diabetes Self-Care Activities and Multidimensional Scale of Perceived Social Support, with hemoglobin A 1 C test. Data were analyzed using descriptive statistics and independent t -test, analysis of variance, Pearson correlation, and linear regression test, using 0.05 as the critical significance level, provided by SPSS software. The mean and standard deviation of self-care and social support scores were 4.31 ± 2.7 and 50.32 ± 11.09, respectively. The mean level of glycosylated hemoglobin (HbA 1 C) of patients was 7.54. There was a significant difference between mean score of self-care behaviors and social support according to gender and marital status ( P social support significantly correlated ( r = 0.489, P > 0.001) and also predictive power of social support was 0.28. Self-care was significantly better in diabetics with HbA 1 C ≤7%. Patients who had higher HbA 1 C felt less, but not significant, social support. This study indicated the relationship between social support and self-care behaviors in type 2 diabetic patients. Interventions that focus on improving the social support and self-care of diabetic control may be more effective in improving glycemic control.

A precise measurement of the left-right cross section asymmetry in Z boson production

Energy Technology Data Exchange (ETDEWEB)

Lath, A.

1994-09-01

The thesis presents a measurement of the left-right asymmetry, A{sub LR}, n the production cross section of Z Bosons produced by e{sup +}e{sup -} annihilations, using polarized electrons, at a center of mass energy of 91.26 Gev. The data presented was recorded by the SLD detector at the SLAC Linear Collider during the 1993 run. The mean luminosity-weighted polarization of the electron beam was {rho}{sup lum} = (63.0{+-}1.1)%. Using a sample of 49,392 Z events, we measure A{sub LR} to be 0.1626{+-}0.0071(stat){+-}0.0030(sys.), which determined the effective weak mixing angle to be sin{sup 2} {theta}{sub W}{sup eff} = 0.2292{+-}0.0009(stat.){+-}0.0004(sys.). This result differs from that expected by the Standard Model of Particles and Fields by 2.5 standard deviations.

A precise measurement of the left-right cross section asymmetry in Z boson production

International Nuclear Information System (INIS)

Lath, A.

1994-09-01

The thesis presents a measurement of the left-right asymmetry, A LR , n the production cross section of Z Bosons produced by e + e - annihilations, using polarized electrons, at a center of mass energy of 91.26 Gev. The data presented was recorded by the SLD detector at the SLAC Linear Collider during the 1993 run. The mean luminosity-weighted polarization of the electron beam was ρ lum = (63.0±1.1)%. Using a sample of 49,392 Z events, we measure A LR to be 0.1626±0.0071(stat)±0.0030(sys.), which determined the effective weak mixing angle to be sin 2 θ W eff = 0.2292±0.0009(stat.)±0.0004(sys.). This result differs from that expected by the Standard Model of Particles and Fields by 2.5 standard deviations

Is the quasielastic pion cross section really bigger than the pion-nucleus reaction cross section

International Nuclear Information System (INIS)

Silbar, R.R.

1979-01-01

It is shown that soft pion charge exchanges may increase the inclusive (π + ,π 0 ') cross section, relative to the total quasielastic (π + ,π + ') cross section, by as much as a factor of two. 4 references

Search for photinos in e/sup +/e/sup -/ annihilation

Energy Technology Data Exchange (ETDEWEB)

Ellis, J; Hagelin, J S [Stanford Linear Accelerator Center, CA (USA). Theory Group

1983-03-10

We discuss the pair production of massive photinos or other neutral gauginos in e/sup +/e/sup -/ annihilation. We present cross sections for e/sup +/e/sup -/->..gamma gamma.. and e/sup +/e/sup -/->..gamma gamma gamma.. including finite mass effects for both the selectron and the gaugino. Experimental signatures are a possible pair of photons from ..gamma.. decay each with =1/4Esub(cm) and a single soft photon in the case of radiative pair production. We exhibit the domains of selectron and gaugino masses and of the supersymmetry breaking scale parameter that could be probed by dedicated searches, pointing out that the present PETRA and PEP centre-of-mass energies are nearly ideal for light gaugino hunts.

Orthopaedic nurses' perception of research utilization - A cross sectional survey

DEFF Research Database (Denmark)

Berthelsen, Connie Bøttcher; Hølge-Hazelton, Bibi

2015-01-01

The call for evidence-based knowledge in clinical nursing practice has increased during recent decades and research in orthopaedic nursing is needed to improve patients' conditions, care and treatment. A descriptive cross-sectional survey was conducted to determine the self-perceived theoretical....... The results indicated that despite the majority of orthopaedic nurses having low self-perceived theoretical knowledge and practical research competencies, their interest and motivation to improve these were high, especially their inner motivation. However, the nurses' inner motivation was inhibited by a lack...

Relativistic quantum mechanic calculation of photoionization cross-section of hydrogenic and non-hydrogenic states using analytical potentials

International Nuclear Information System (INIS)

Rodriguez, R.; Gil, J.M.; Rubiano, J.G.; Florido, R.; Martel, P.; Minguez, E.

2005-01-01

Photoionization process is a subject of special importance in many areas of physics. Numerical methods must be used in order to obtain photoionization cross-sections for non-hydrogenic levels. The atomic data required to calculate them is huge so self-consistent calculations increase computing time considerably. Analytical potentials are a useful alternative because they avoid the iterative procedures typical in self-consistent models. In this work, we present a relativistic quantum calculation of photoionization cross-sections for isolated ions based on an analytical potential to obtain the required atomic data, which is valid both for hydrogenic and non-hydrogenic ions. Comparisons between our results and others obtained using either widely used analytical expressions for the cross-sections or more sophisticated calculations are done

JENDL gas-production cross section file

International Nuclear Information System (INIS)

Nakagawa, Tsuneo; Narita, Tsutomu

1992-05-01

The JENDL gas-production cross section file was compiled by taking cross-section data from JENDL-3 and by using the ENDF-5 format. The data were given to 23 nuclei or elements in light nuclei and structural materials. Graphs of the cross sections and brief description on their evaluation methods are given in this report. (author)

Applications of the nuclear theory to the computation of neutron cross sections for actinide isotopes

International Nuclear Information System (INIS)

Konshin, V.A.

1981-01-01

Neutron cross section calculational methods for actinides in the unresolved resonance energy range (1-150 kev) are discussed, with a special emphasis on calculation of width fluctuation factors for the generalized distribution, as well as for a sub-threshold fission. It is shown that the energy dependence of sub(J), the (n,n') -process competition and the structure in neutron cross section has to be taken into account in the energy range considered. Analysis of different approaches in the statistical theory for heavy nuclei neutron cross-section calculation is given, and it is shown to be important to allow for the (n,γf)-reaction in neutron cross section calculations for fissile nuclei. The use of the non-spherical potential, the Lorentzian spectral factor and the Fermi-gas model involving the collective modes enables to obtain the self-consistent data for all neutron cross sections, including σnγ. (author)

Doppler broadening of cross sections

International Nuclear Information System (INIS)

Buckler, P.A.C.; Pull, I.C.

1962-12-01

Expressions for temperature dependent cross-sections in terms of resonance parameters are obtained, involving generalisations of the conventional Doppler functions, ψ and φ. Descriptions of Fortran sub-routines, which calculate broadened cross-sections in accordance with the derived formulae, are included. (author)

Kalpakkam multigroup cross section set for fast reactor applications - status and performance

International Nuclear Information System (INIS)

Ramanadhan, M.M.; Gopalakrishnan, M.M.

1986-01-01

This report documents the status of the presently created set of multigroup constants at Kalpakkam. The list of nuclides processed and the details of multigroup structure are given. Also included are the particulars of dilutions and temperatures for each nuclide in the multigroup cross section set for which self shielding factors have been calculated. Using this new multigroup cross section set, measured integral quantities such as K-eff, central reaction rate ratios, central reactivity worths etc. were calculated for a few fast critical benchmark assemblies and the calculated values of neutronic parameters obtained were compared with those obtained using the available Cadarache cross section library and those published in literature for ENDF/B-IV based set and Japanese evaluated nuclear data library (JENDL). The details of analyses are documented along with the conclusions. (author). 17 refs., 12 tabs

Single-top s channel cross-section measurement with the ATLAS detector

CERN Document Server

Monini, Caterina; Lucotte, Arnaud

The work reported in this thesis is aimed at measuring with the ATLAS detector the only mechanism of top quark electroweak production which has not yet been observed at the Large Hadron Collider: the s-channel. Its interest relies in the confirmation of the Standard Model predictions but, as well, in the possibility of constraining several new physics scenarios when comparing the s-channel cross section with the one of the other single top production modes (the Wt and t-channel). After a general introduction upon top physics and the experimental setup employed for the detection and the reconstruction of the physics objects, we present two analyses realized with proton-proton collisions collected by the ATLAS detector at a center of mass energy of 7 and 8 TeV. Since the s-channel production is characterized by a very low purity and, at the same time, is not favoured at the LHC because it proceeds via quark-antiquark annihilation, a multivariate approach is applied in both cases to discriminate the signal. For ...

Electron - A fortran programme for the coupled channel calculation of nuclear electromagnetic (e,e') form factors and cross sections in the self-consistent random-phase approximation

International Nuclear Information System (INIS)

Cavinato, M.; Marangoni, M.; Saruis, A.M.

1984-01-01

Description is given of the Electron programme for IBM 370/168 computer, written in Fortran 4. language. The programme calculates (e,e') cross-sections and longitudinal/transverse form factors for closed shell nuclei in the framework of a self-consistent RPA theory

Inclusive production of Λ and anti Λ particles in e+e- annihilations at 29 GeV

International Nuclear Information System (INIS)

Vaissiere, C. de la.

1983-11-01

The large amount of data accumulated and the opportunities offered by the vertex chamber, give us over the other groups the advantage of a much larger and clean Λ sample. This allow us to probe the production of baryons in e + e - annihilations. The following subjects are presented: results on cross-sections agrees with TASSO; the baryon number seems predominantly conserved locally, inside one jet; a preliminary jet analysis does not suggest a strong preference of gluon jets for Λs

Assessment of Knowledge of Self Blood Glucose Monitoring and Extent of Self Titration of Anti-Diabetic Drugs among Diabetes Mellitus Patients - A Cross Sectional, Community Based Study.

Science.gov (United States)

Krishnan, V; Thirunavukkarasu, J

2016-03-01

Self blood glucose monitoring is an important context of self care in the management of diabetes mellitus. All the guidelines must be followed while performing self blood glucose monitoring and tracking of values is essential to facilitate the physician while titrating the drugs and /or doses of anti diabetes medication. Self titration by patients following self monitoring must be discouraged. To assess the knowledge and practice of self blood glucose monitoring among diabetes patients and extent of self titration of anti diabetes medicines among diabetes patients based on self blood glucose monitoring. This pilot, cross-sectional, observational study was conducted using a validated questionnaire among adult male and female diabetes patients performing self blood glucose monitoring at home. Diabetes patients with complications and juvenile diabetes patients were excluded. Out of 153 patients surveyed, only 37 (24.1%) (20 males, 17 females) patients were aware and have been following self blood glucose monitoring appropriately. About 116 (75.8%) (64 males, 52 females) of patients were devoid of adequate knowledge and did not practice self blood glucose monitoring in a proper way. Ninety eight (64.05%) accepted that they self titrate their anti diabetic medicines based on self monitoring. Self monitoring of blood glucose should be encouraged and patients should be taught importance of following correct steps and tracking of self monitoring by physician or diabetes educator.

Density-dependent expressions for photoionization cross-sections

International Nuclear Information System (INIS)

Sun Weiguo; Ma Xiaoguang; Cheng Yansong

2004-01-01

Alternative expressions for photoionization cross-sections and dielectric influence functions are suggested to study the photoionization cross-sections of atoms in solid system. The basic picture is that the photoionization cross-section of atoms in a real system can be described as the coupling between quantum quantity (QQ) and classical quantity (CQ) parts. The QQ part represents the photoionization cross-sections of an isolated particle, while the CQ part may represent most of the important influence of the macroscopic effects (e.g., the interactions of all surrounding polarized particles, and the dielectric property, etc.) on the photoionization cross-sections. The applications to the barium system show that the number-density-dependent new photoionization formula not only obtains the same cross-sections as those from the first order approximation for ideal gas, but also can generate the cross-sections for solid barium by transforming those of ideal gas of the same species using the dielectric influence function

Density-dependent expressions for photoionization cross-sections

Energy Technology Data Exchange (ETDEWEB)

Sun Weiguo; Ma Xiaoguang; Cheng Yansong

2004-06-07

Alternative expressions for photoionization cross-sections and dielectric influence functions are suggested to study the photoionization cross-sections of atoms in solid system. The basic picture is that the photoionization cross-section of atoms in a real system can be described as the coupling between quantum quantity (QQ) and classical quantity (CQ) parts. The QQ part represents the photoionization cross-sections of an isolated particle, while the CQ part may represent most of the important influence of the macroscopic effects (e.g., the interactions of all surrounding polarized particles, and the dielectric property, etc.) on the photoionization cross-sections. The applications to the barium system show that the number-density-dependent new photoionization formula not only obtains the same cross-sections as those from the first order approximation for ideal gas, but also can generate the cross-sections for solid barium by transforming those of ideal gas of the same species using the dielectric influence function.

Self-reported eating rate is associated with weight status in a Dutch population: a validation study and a cross-sectional study.

Science.gov (United States)

van den Boer, Janet H W; Kranendonk, Jentina; van de Wiel, Anne; Feskens, Edith J M; Geelen, Anouk; Mars, Monica

2017-09-08

Observational studies performed in Asian populations suggest that eating rate is related to BMI. This paper investigates the association between self-reported eating rate (SRER) and body mass index (BMI) in a Dutch population, after having validated SRER against actual eating rate. Two studies were performed; a validation and a cross-sectional study. In the validation study SRER (i.e., 'slow', 'average', or 'fast') was obtained from 57 participants (men/women = 16/41, age: mean ± SD = 22.6 ± 2.8 yrs., BMI: mean ± SD = 22.1 ± 2.8 kg/m 2 ) and in these participants actual eating rate was measured for three food products. Using analysis of variance the association between SRER and actual eating rate was studied. The association between SRER and BMI was investigated in cross-sectional data from the NQplus cohort (i.e., 1473 Dutch adults; men/women = 741/732, age: mean ± SD = 54.6 ± 11.7 yrs., BMI: mean ± SD = 25.9 ± 4.0 kg/m 2 ) using (multiple) linear regression analysis. In the validation study actual eating rate increased proportionally with SRER (for all three food products P men and women (P = 0.03 and P men; self-reported fast-eating men had a 0.29 kg/m 2 (95% CI -0.22, 0.80) higher BMI compared to average-speed-eating men, after adjusting for confounders. These studies show that self-reported eating rate reflects actual eating rate on a group-level, and that a high self-reported eating rate is associated with a higher BMI in this Dutch population.

System THEMIS. Cross sections processing system from ENDF/B

International Nuclear Information System (INIS)

Gonnord, J.

1983-09-01

The THEMIS system allowed to prepare a self punctual and multigroup library for codes solving the TRIPOLI-PROMETHEE transport equation, allowing comparisons with different methods and approximations. The contents of the THEMIS data base was fixed from its use by the PROMETHEE system (punctual Monte Carlo calculations, multigroup calculations, uncertainties analysis and sensitivity studies). The main characteristics of the THEMIS cross section processing system are briefly presented [fr

Correlation Between Critical Thinking Disposition and Mental Self-Supporting Ability in Nursing Undergraduates: A Cross-Sectional Descriptive Study.

Science.gov (United States)

Wu, Defang; Luo, Yang; Liao, Xinyu

2017-02-01

There is universal agreement on the essential role of critical thinking in nursing practice. Most studies into this topic have provided descriptive statistical information and insights on related external factors such as educational environment and teaching strategies. However, there has been limited research into the psychological factors that may predict the disposition of students toward critical thinking. This study explored the relationship between the disposition of nursing students toward critical thinking and their mental self-supporting ability to obtain a profile and determine the psychological predictors of critical thinking. A cross-sectional descriptive study was conducted in 2013 using a convenience sample from four nursing schools. Four hundred six Chinese nursing undergraduates completed two questionnaires including (a) the California Critical Thinking Disposition Inventory (Chinese version) and (b) the Mental Self-Supporting Questionnaire for University Students. Pearson's correlation and linear regression analysis were used to investigate the relationship between these two variables and the predicted positive psychological qualities for the critical thinking disposition of participants. Average participant scores for critical thinking disposition and mental self-supporting were 280.91 ± 28.43 and 76.40 ± 8.47, respectively. Positive correlations were observed between these two variables (r = .583, p critical thinking disposition (R = .435, p critical thinking and mental self-supporting abilities.The four factors that had a major influence on critical thinking disposition included self-decision, self-cognition, self-confidence, and self-responsibility. Nursing educators should focus on improving the critical thinking ability of their students in these four aspects.

A subtraction scheme for computing QCD jet cross sections at NNLO. Integrating the iterated singly-unresolved subtraction terms

Energy Technology Data Exchange (ETDEWEB)

Bolzoni, Paolo [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Somogyi, Gabor [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Zoltan [Debrecen Univ. (Hungary); Hungarian Academy of Sciences, Debrecen (Hungary). Inst. of Nuclear Research

2010-11-15

We perform the integration of all iterated singly-unresolved subtraction terms over the two-particle factorized phase space. We also sum over the unresolved parton flavours. The final result can be written as a convolution (in colour space) of the Born cross section and an insertion operator. We spell out the insertion operator in terms of 24 basic integrals that are defined explicitly. We compute the coefficients of the Laurent-expansion of these integrals in two different ways, with the method of Mellin-Barnes representations and sector decomposition. Finally, we present the Laurentexpansion of the full insertion operator for the specific examples of electron-positron annihilation into two and three jets. (orig.)

A subtraction scheme for computing QCD jet cross sections at NNLO: integrating the iterated singly-unresolved subtraction terms

Science.gov (United States)

Bolzoni, Paolo; Somogyi, Gábor; Trócsányi, Zoltán

2011-01-01

We perform the integration of all iterated singly-unresolved subtraction terms, as defined in ref. [1], over the two-particle factorized phase space. We also sum over the unresolved parton flavours. The final result can be written as a convolution (in colour space) of the Born cross section and an insertion operator. We spell out the insertion operator in terms of 24 basic integrals that are defined explicitly. We compute the coefficients of the Laurent expansion of these integrals in two different ways, with the method of Mellin-Barnes representations and sector decomposition. Finally, we present the Laurent-expansion of the full insertion operator for the specific examples of electron-positron annihilation into two and three jets.

Statistical Modelling of Resonant Cross Section Structure in URR, Model of the Characteristic Function

International Nuclear Information System (INIS)

Koyumdjieva, N.

2006-01-01

A statistical model for the resonant cross section structure in the Unresolved Resonance Region has been developed in the framework of the R-matrix formalism in Reich Moore approach with effective accounting of the resonance parameters fluctuations. The model uses only the average resonance parameters and can be effectively applied for analyses of cross sections functional, averaged over many resonances. Those are cross section moments, transmission and self-indication functions measured through thick sample. In this statistical model the resonant cross sections structure is accepted to be periodic and the R-matrix is a function of ε=E/D with period 0≤ε≤N; R nc (ε)=π/2√(S n *S c )1/NΣ(i=1,N)(β in *β ic *ctg[π(ε i - = ε-iS i )/N]; Here S n ,S c ,S i is respectively neutron strength function, strength function for fission or inelastic channel and strength function for radiative capture, N is the number of resonances (ε i ,β i ) that obey the statistic of Porter-Thomas and Wigner's one. The simple case of this statistical model concerns the resonant cross section structure for non-fissile nuclei under the threshold for inelastic scattering - the model of the characteristic function with HARFOR program. In the above model some improvements of calculation of the phases and logarithmic derivatives of neutron channels have been done. In the parameterization we use the free parameter R l ∞ , which accounts the influence of long-distant resonances. The above scheme for statistical modelling of the resonant cross section structure has been applied for evaluation of experimental data for total, capture and inelastic cross sections for 232 Th in the URR (4-150) keV and also the transmission and self-indication functions in (4-175) keV. The set of evaluated average resonance parameters have been obtained. The evaluated average resonance parameters in the URR are consistent with those in the Resolved Resonance Region (CRP for Th-U cycle, Vienna, 2006

Total neutron cross section of lead

International Nuclear Information System (INIS)

Kanda, K.; Aizawa, O.

1976-01-01

The total thermal-neutron cross section of natural lead under various physical conditions was measured by the transmission method. It became clear that the total cross section at room temperature previously reported is lower than the present data. The total cross section at 400, 500, and 600 0 C, above the melting point of lead, 327 0 C, was also measured, and the changes in the cross section as a function of temperature were examined, especially near and below the melting point. The data obtained for the randomly oriented polycrystalline state at room temperature were in reasonable agreement with the theoretical values calculated by the THRUSH and UNCLE-TOM codes

A cross-sectional study of self-reported general health, lifestyle factors, and disease: the Hordaland Health Study

Directory of Open Access Journals (Sweden)

Randi Jepsen

2014-10-01

Full Text Available Background. Information on self-reported health is important for health professionals, and the aim of this study was to examine associations between lifestyle factors and self-reported health and the mediating effect of disease in a Norwegian population.Methods and Materials. The data collection was conducted as part of the Hordaland Health Study (HUSK 1997–99, which was a cross-sectional epidemiological study. All individuals in Hordaland county born in 1953–1957 were invited to participate (aged 40–44 years. Complete information for the present study was obtained from 12,883 individuals (44% response rate. Height and weight were measured at a physical examination. Information on lifestyle factors, self-reported health, disease (heart attack, apoplexy, angina pectoris, and diabetes, and socio-demographic variables was obtained from a self-administered questionnaire. Self-reported health was measured with a one-item question. Odds ratios for fair or poor self-reported health were calculated using multiple logistic regression analyses adjusted for disease and socio-demographic variables.Results. Respondents reporting adverse lifestyle behaviours (obesity (odds ratio (OR 1.7, p < 0.001, smoking (OR 1.2, p < 0.001, or excessive intake of alcohol (OR 3.3, p < 0.001 showed an increased risk of poor self-reported health. Furthermore, a moderate intake of wine (OR 0.6, p < 0.001 or strenuous physical activity (OR 0.5, p < 0.001 decreased the risk of poor health. Disease did not mediate the effect.Conclusion. A one-item question measuring self-reported health may be a suitable measure for health professionals to identify levels of subjective health and reveal a need to target lifestyle factors in relatively young individuals with or without disease.

Annihilation probability density and other applications of the Schwinger multichannel method to the positron and electron scattering; Densidade de probabilidade de aniquilacao e outras aplicacoes do metodo multicanal de Schwinger ao espalhamento de positrons e eletrons

Energy Technology Data Exchange (ETDEWEB)

Varella, Marcio Teixeira do Nascimento

2001-12-15

We have calculated annihilation probability densities (APD) for positron collisions against He atom and H{sub 2} molecule. It was found that direct annihilation prevails at low energies, while annihilation following virtual positronium (Ps) formation is the dominant mechanism at higher energies. In room-temperature collisions (10{sup -2} eV) the APD spread over a considerable extension, being quite similar to the electronic densities of the targets. The capture of the positron in an electronic Feshbach resonance strongly enhanced the annihilation rate in e{sup +}-H{sub 2} collisions. We also discuss strategies to improve the calculation of the annihilation parameter (Z{sub eff} ), after debugging the computational codes of the Schwinger Multichannel Method (SMC). Finally, we consider the inclusion of the Ps formation channel in the SMC and show that effective configurations (pseudo eigenstates of the Hamiltonian of the collision ) are able to significantly reduce the computational effort in positron scattering calculations. Cross sections for electron scattering by polyatomic molecules were obtained in three different approximations: static-exchange (SE); tatic-exchange-plus-polarization (SEP); and multichannel coupling. The calculations for polar targets were improved through the rotational resolution of scattering amplitudes in which the SMC was combined with the first Born approximation (FBA). In general, elastic cross sections (SE and SEP approximations) showed good agreement with available experimental data for several targets. Multichannel calculations for e{sup -} -H{sub 2}O scattering, on the other hand, presented spurious structures at the electronic excitation thresholds (author)

Top quark production cross-section measurements

CERN Document Server

Chen, Ye; The ATLAS collaboration

2017-01-01

Measurements of the inclusive and differential cross-sections for top-quark pair and single top production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at center-of-mass energies of 8 TeV and 13 TeV. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. These measurements, including results using boosted tops, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For the t-channel single top measurement, the single top-quark and anti-top-quark total production cross-sections, their ratio, as well as differential cross sections are also presented. A measurement of the production cross-section of a single top quark in association with a W boson, the second largest single-top production mode, is also presented. Finally, measurements of ...

Nuclear-charge and positron-energy dependence of the single-quantum annihilation of positrons

International Nuclear Information System (INIS)

Palathingal, J.C.; Asoka-Kumar, P.; Lynn, K.G.; Wu, X.Y.

1995-01-01

We report an experimental study of the single-quantum annihilation of positrons in a number of elements having atomic numbers between 49 and 90, utilizing a monoenergetic positron beam. Measurements were made of the differential cross sections for the forward direction for the K, L, and M atomic shells in targets of Th, Pb, Au, Hf, Gd, and In, having thicknesses that vary between 2.7 and 4.4 mg/cm 2 . A shielded HPGe detector of high relative photopeak efficiency was used for recording the photon spectrum. Values for the individual atomic shells were obtained in the positron kinetic-energy range 1.02--2.24 MeV. It was observed that the differential cross sections measured for the forward direction varied with energy for each major shell almost alike so that the shell ratios appeared to remain constant while the positron energy varied. The dependence of the cross section on the atomic number Z of the target element was tested for each of the major shells at various energies of measurement. It was seen that the cross sections follow a Z ν relation with ν∼5.1 as the exponent for the K shell. For the higher shells, the exponent is approximately 6.4, which is significantly larger. It was also noted that this pattern is fairly independent of the positron energy. The results on the Z dependence are seen to be clearly at variance with the most updated theoretical predictions

Determinants of self-efficacy and quality of life in patients with temporary enterostomy: a cross-sectional survey.

Science.gov (United States)

Su, Xi; Zhen, Li; Zhu, Mulan; Kuang, Yinyi; Qin, Fang; Ye, Xinmei; Yin, Xuexia; Wang, Huizhen

2017-02-01

To identify determinants of self-efficacy and quality of life in patients with temporary enterostomy. Anterior resection with temporary enterostomy is the preferred treatment for patients with rectal cancer, which may impair patients' quality of life. So far, most studies have focused on quality of life in patients with permanent enterostomy, but few studies have looked at that in those with temporary enterostomy. Self-efficacy may determine quality of life in these patients, but few studies have identified determinants of self-efficacy and quality of life. Multicentre, cross-sectional survey and regression analysis to identify determinants of self-efficacy and quality of life. A convenience sample of patients undergoing temporary enterostomy at five hospitals in Guangdong Province (China) were surveyed at least four weeks after stoma surgery using validated Chinese versions of internationally recognised questionnaires, including a Stoma Self-Efficacy Scale and the City of Hope Quality of Life-Ostomy Questionnaire. Backward multiple regression analysis was performed to identify whether quality of life was determined by self-efficacy and other clinico-demographic characteristics. Of the 180 questionnaires distributed, 149 (82·8%) were returned, and 135 (75%) were used in the final analysis. Mean global quality of life was 5·40 ± 1·58, and mean global self-efficacy was 79·59 ± 20·21. Significant determinants of self-efficacy and quality of life were identified (β = 0·62, p < 0·01). Quality of life was determined by type of enterostomy (β = 0·18, p = 0·01) and payment method (β = 0·14, p = 0·03). Quality of life may be determined by self-efficacy, type of enterostomy and payment method, after temporary enterostomy. Promoting stoma-related self-efficacy in patients with temporary enterostomy may improve their quality of life. Healthcare providers should focus on quality of life in those either with temporary loop ileostomy or entirely

Differences between LASL- and ANL-processed cross sections

International Nuclear Information System (INIS)

Kidman, R.B.; MacFarlane, R.E.; Becker, M.

1978-03-01

As part of the Los Alamos Scientific Laboratory (LASL) cross-section processing development, LASL cross sections and results from MINX/1DX system are compared to the Argonne National Laboratory cross sections and results from the ETOE-2/MC 2 -2 system for a simple reactor problem. Exact perturbation theory is used to establish the eigenvalue effect of every isotope group cross-section difference. Cross sections, cross-section differences, and their eigenvalue effects are clearly and conveniently displayed and compared on a group-by-group basis

X-Ray Lines from Dark Matter Annihilation at the keV Scale.

Science.gov (United States)

Brdar, Vedran; Kopp, Joachim; Liu, Jia; Wang, Xiao-Ping

2018-02-09

In 2014, several groups reported hints for a yet unidentified line in astrophysical x-ray signals from galaxies and galaxy clusters at an energy of 3.5 keV. While it is not unlikely that this line is simply a reflection of imperfectly modeled atomic transitions, it has renewed the community's interest in models of keV-scale dark matter, whose decay would lead to such a line. The alternative possibility of dark matter annihilation into monochromatic photons is far less explored, a lapse that we strive to amend in this Letter. More precisely, we introduce a novel model of fermionic dark matter χ with O(keV) mass, annihilating to a scalar state ϕ which in turn decays to photons, for instance via loops of heavy vectorlike fermions. The resulting photon spectrum is box shaped, but if χ and ϕ are nearly degenerate in mass, it can also resemble a narrow line. We discuss dark matter production via two different mechanisms-misalignment and freeze-in-which both turn out to be viable in vast regions of parameter space. We constrain the model using astrophysical x-ray data, and we demonstrate that, thanks to the velocity dependence of the annihilation cross section, it has the potential to reconcile the various observations of the 3.5 keV line. We finally argue that the model can easily avoid structure formation constraints on keV-scale dark matter.

(n,{alpha}) cross section measurement of gaseous sample using gridded ionization chamber. Cross section determination

Energy Technology Data Exchange (ETDEWEB)

Sanami, Toshiya; Baba, Mamoru; Saito, Keiichiro; Ibara, Yasutaka; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

1997-03-01

We are developing a method of (n,{alpha}) cross section measurement using gaseous samples in a gridded ionization chamber (GIC). This method enables cross section measurements in large solid angle without the distortion by the energy loss in a sample, but requires a method to estimate the detection efficiency. We solve this problem by using GIC signals and a tight neutron collimation. The validity of this method was confirmed through the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be measurement. We applied this method to the {sup 16}O(n,{alpha}){sup 13}C cross section around 14.1 MeV. (author)

Antiproton-neon annihilation at rest and at 607 MeV/c

International Nuclear Information System (INIS)

Balestra, F.; Bossolasco, S.; Bussa, M.P.; Busso, L.; Ferrero, L.; Panzieri, D.; Piragino, G.; Tosello, F.; Barbieri, R.; Bendiscioli, G.; Rotondi, A.; Salvini, P.; Zenoni, A.; Batusov, Yu.A.; Falomkin, I.V.; Pontecorvo, G.B.; Sapozhnikov, M.G.; Tretyak, V.I.; Guaraldo, C.; Maggiora, A.; Haatuft, A.; Halsteinslid, A.; Myklebost, K.; Olsen, J.M.; Breivik, F.O.; Jacobsen, T.; Soerensen, S.O.

1989-01-01

The analysis is based upon anti pNe annihilation events at rest and at 607 MeV/c detected with a self-shunted streamer chamber exposed to the LEAR beams. The main measured quantities are the following: charged-prong multiplicity, negative pion multiplicity; momentum, angular and rapidity distributions. General distributions are given as well as distributions as functions of charged prong multiplicity. A correlation is found between high multiplicity and depth of the annihilation point. The data are compared with recent theoretical analyses. (orig.)

Correlations between TD annihilation and oxygen precipitation in Czochralski-grown silicon

International Nuclear Information System (INIS)

Reiche, M.

1989-01-01

Results of two-stage annealing experiments are presented including preannealing at T o C (TD formation) and a second annealing step at T=550 to 850 o C in order to study the annihilation of TD's and their influence on the oxygen precipitation. The investigations show that (1) TD's cannot act as nuclei for oxide precipitates and that (2) their annihilation, connected with the increased formation of Si I induced defects (RLD's), proves TD's to consist also of self-interstitials. (author) 11 refs., 4 figs

Photoionization cross section of atomic and molecular oxygen

International Nuclear Information System (INIS)

Pareek, P.N.

1983-01-01

Photoionization cross sections of atomic oxygen and dissociative photoionization cross sections of molecular oxygen were measured from their respective thresholds to 120 angstrom by use of a photoionization mass spectrometer in conjunction with a spark light source. The photoionization cross sections O 2 + parent ion and O + fragment ion from neutral O 2 were obtained by a technique that eliminated the serious problem of identifying the true abundances of O + ions. These ions are generally formed with considerable kinetic energy and, because most mass spectrometers discriminate against energetic ions, true O + abundances are difficult to obtain. In the present work the relative cross sections for producing O + ions are obtained and normalized against the total cross sections in a spectral region where dissociative ionization is not possible. The fragmentation cross sections for O + were then obtained by subtraction of O 2 + cross sections from the known total photoionization cross sections. The results are compared with the previously published measurements. The absolute photoionization cross section of atomic oxygen sigma 8 /sub +/ was measured at 304 A. The actual number density of oxygen atoms within the ionization region was obtained by measuring the fraction of 0 2 molecules dissociated. This sigma/sub +/ at 304 angstrom was used to convert the relative photoinization cross sections, measured as a function of wavelength using a calibrated photodiode, to absolute cross sections. The results are compared with previous measurements and calculated cross sections. angstrom Rydberg series converging to the OII 4 P state was observed

Measurements of neutron capture cross sections

International Nuclear Information System (INIS)

Nakajima, Yutaka

1984-01-01

A review of measurement techniques for the neutron capture cross sections is presented. Sell transmission method, activation method, and prompt gamma-ray detection method are described using examples of capture cross section measurements. The capture cross section of 238 U measured by three different prompt gamma-ray detection methods (large liquid scintillator, Moxon-Rae detector, and pulse height weighting method) are compared and their discrepancies are resolved. A method how to derive the covariance is described. (author)

XCOM: Photon Cross Sections Database

Science.gov (United States)

SRD 8 XCOM: Photon Cross Sections Database (Web, free access)   A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z <= 100) at energies from 1 keV to 100 GeV.

Graphs of the cross sections in the recommended Monte Carlo cross-section library at the Los Alamos Scientific Laboratory

International Nuclear Information System (INIS)

Soran, P.D.; Seamon, R.E.

1980-05-01

Graphs of all neutron cross sections and photon production cross sections on the Recommended Monte Carlo Cross Section (RMCCS) library have been plotted along with local neutron heating numbers. Values for anti ν, the average number of neutrons per fission, are also given

THE DETECTABILITY OF DARK MATTER ANNIHILATION WITH FERMI USING THE ANISOTROPY ENERGY SPECTRUM OF THE GAMMA-RAY BACKGROUND

International Nuclear Information System (INIS)

Hensley, Brandon S.; Pavlidou, Vasiliki; Siegal-Gaskins, Jennifer M.

2010-01-01

The energy dependence of the anisotropy (the anisotropy energy spectrum) of the large-scale diffuse gamma-ray background can reveal the presence of multiple source populations. Annihilating dark matter in the substructure of the Milky Way halo could give rise to a modulation in the anisotropy energy spectrum of the diffuse gamma-ray emission measured by Fermi, enabling the detection of a dark matter signal. We determine the detectability of a dark-matter-induced modulation for scenarios in which unresolved blazars are the primary contributor to the measured emission above ∼1 GeV and find that in some scenarios pair-annihilation cross sections on the order of the value expected for thermal relic dark matter can produce a detectable feature. We anticipate that the sensitivity of this technique to specific dark matter models could be improved by tailored likelihood analysis methods.

Scattering cross section for various potential systems

Directory of Open Access Journals (Sweden)

Myagmarjav Odsuren

2017-08-01

Full Text Available We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.

Scattering cross section for various potential systems

Energy Technology Data Exchange (ETDEWEB)

Odsuren, Myagmarjav; Khuukhenkhuu, Gonchigdorj; Davaa, Suren [Nuclear Research Center, School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar (Mongolia); Kato, Kiyoshi [Nuclear Reaction Data Centre, Faculty of Science, Hokkaido University, Sapporo (Japan)

2017-08-15

We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.

Ethnic differences in the self-recognition of obesity and obesity-related comorbidities: a cross-sectional analysis.

Science.gov (United States)

Sivalingam, Senthil K; Ashraf, Javed; Vallurupalli, Neelima; Friderici, Jennifer; Cook, James; Rothberg, Michael B

2011-06-01

Obesity and its related co-morbidities place a huge burden on the health care system. Patients who know they are obese may better control their weight or seek medical attention. Self-recognition may be affected by race/ethnicity, but little is known about racial/ethnic differences in knowledge of obesity's health risks. To examine awareness of obesity and attendant health risks among US whites, Hispanics and African-Americans. Cross-sectional self-administered survey. Adult patients at three general medical clinics and one cardiology clinic. Thirty-one questions regarding demographics, height and weight, and perceptions and attitudes regarding obesity and associated health risks. Multiple logistic regression was used to quantify the association between ethnicity and obesity awareness, controlling for socio-demographic confounders. Of 1,090 patients who were offered the survey, 1,031 completed it (response rate 95%); a final sample size of 970 was obtained after exclusion for implausible BMI, mixed or Asian ethnicity. Mean age was 47 years; 64% were female, 39% were white, 39% Hispanic and 22% African-American; 48% were obese (BMI ≥30 kg/m(2)). Among obese subjects, whites were more likely to self-report obesity than minorities (adjusted proportions: 95% of whites vs. 84% of African-American and 86% of Hispanics, P = 0.006). Ethnic differences in obesity recognition disappeared when BMI was >35 kg/m(2). African-Americans were significantly less likely than whites or Hispanics to view obesity as a health problem (77% vs. 90% vs. 88%, p self-identified obese patients, 99% wanted to lose weight, but only 60% received weight loss advice from their health care provider. African-Americans and Hispanics are significantly less likely to self report obesity and associated health risks. Educational efforts may be necessary, especially for patients with BMIs between 30 and 35.

Burnout Subtypes and Absence of Self-Compassion in Primary Healthcare Professionals: A Cross-Sectional Study.

Directory of Open Access Journals (Sweden)

Jesus Montero-Marin

Full Text Available Primary healthcare professionals report high levels of distress and burnout. A new model of burnout has been developed to differentiate three clinical subtypes: 'frenetic', 'underchallenged' and 'worn-out'. The aim of this study was to confirm the validity and reliability of the burnout subtype model in Spanish primary healthcare professionals, and to assess the explanatory power of the self-compassion construct as a possible protective factor.The study employed a cross-sectional design. A sample of n = 440 Spanish primary healthcare professionals (214 general practitioners, 184 nurses, 42 medical residents completed the Burnout Clinical Subtype Questionnaire (BCSQ-36, the Maslach Burnout Inventory General Survey (MBI-GS, the Self-Compassion Scale (SCS, the Utrecht Work Engagement Scale (UWES and the Positive and Negative Affect Schedule (PANAS. The factor structure of the BCSQ-36 was estimated using confirmatory factor analysis (CFA by the unweighted least squares method from polychoric correlations. Internal consistency (R was assessed by squaring the correlation between the latent true variable and the observed variables. The relationships between the BCSQ-36 and the other constructs were analysed using Spearman's r and multiple linear regression models.The structure of the BCSQ-36 fit the data well, with adequate CFA indices for all the burnout subtypes. Reliability was adequate for all the scales and sub-scales (R≥0.75. Self-judgement was the self-compassion factor that explained the frenetic subtype (Beta = 0.36; p<0.001; isolation explained the underchallenged (Beta = 0.16; p = 0.010; and over-identification the worn-out (Beta = 0.25; p = 0.001. Other significant associations were observed between the different burnout subtypes and the dimensions of the MBI-GS, UWES and PANAS.The typological definition of burnout through the BCSQ-36 showed good structure and appropriate internal consistence in Spanish primary healthcare professionals

Testing of cross-section functionals in the unresolved resonance region

International Nuclear Information System (INIS)

Koshcheev, V.N.; Krivtsov, A.S.; Sinitsa, V.V.; Ukraintsev, V.F.

1994-01-01

The results of a comparison of the GRUCON, MMK and NJOY data processing codes in the treatment of evaluated neutron data in the unresolved resonance region are presented. The sets of average resonance parameters of 238 U and 239 Pu isotopes, which have been published by Munos-Cobos et al., and Ribon et al., were used in this exercise. Average cross-sections, self-shielding factors and Doppler broadening self-shielding factors are compared with the original results presented by the above-mentioned authors. Conclusions regarding the reliability of the neutron data processing codes are made. (author). 6 refs, 7 tabs

NNLO jet cross sections by subtraction

International Nuclear Information System (INIS)

Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.

2010-06-01

We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)

NNLO jet cross sections by subtraction

Energy Technology Data Exchange (ETDEWEB)

Somogyi, G.; Bolzoni, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Z. [CERN, Geneva (Switzerland)

2010-06-15

We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)

NNLO jet cross sections by subtraction

CERN Document Server

Somogyi, Gabor; Trocsanyi, Zoltan

2010-01-01

We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of [1-4], over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

Differential cross sections and cross-section ratios for the electron-impact excitation of the neon 2p53s configuration

International Nuclear Information System (INIS)

Khakoo, M. A.; Wrkich, J.; Larsen, M.; Kleiban, G.; Kanik, I.; Trajmar, S.; Brunger, M.J.; Teubner, P.J.O.; Crowe, A.; Fontes, C.J.; Clark, R.E.H.; Zeman, V.; Bartschat, K.; Madison, D.H.; Srivastava, R.; Stauffer, A.D.

2002-01-01

Electron-impact differential cross-section measurements for the excitation of the 2p 5 3s configuration of Ne are reported. The Ne cross sections are obtained using experimental differential cross sections for the electron-impact excitation of the n=2 levels of atomic hydrogen [Khakoo et al., Phys. Rev. A 61, 012701-1 (1999)], and existing experimental helium differential cross-section measurements, as calibration standards. These calibration measurements were made using the method of gas mixtures (Ne and H followed by Ne and He), in which the gas beam profiles of the mixed gases are found to be the same within our experimental errors. We also present results from calculations of these differential cross sections using the R-matrix and unitarized first-order many-body theory, the distorted-wave Born approximation, and relativistic distorted-wave methods. Comparison with available experimental differential cross sections and differential cross-section ratios is also presented

Capture cross sections on unstable nuclei

Science.gov (United States)

Tonchev, A. P.; Escher, J. E.; Scielzo, N.; Bedrossian, P.; Ilieva, R. S.; Humby, P.; Cooper, N.; Goddard, P. M.; Werner, V.; Tornow, W.; Rusev, G.; Kelley, J. H.; Pietralla, N.; Scheck, M.; Savran, D.; Löher, B.; Yates, S. W.; Crider, B. P.; Peters, E. E.; Tsoneva, N.; Goriely, S.

2017-09-01

Accurate neutron-capture cross sections on unstable nuclei near the line of beta stability are crucial for understanding the s-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining the most relevant observables that can constrain Hauser-Feshbach statistical-model calculations of capture cross sections. Specifically, we will consider photon scattering using monoenergetic and 100% linearly polarized photon beams. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes near and far from stability will be discussed.

Status of neutron dosimetry cross sections

International Nuclear Information System (INIS)

Griffin, P.J.; Kelly, J.G.

1992-01-01

Several new cross section libraries, such as ENDF/B-VI(release 2), IRDF-90,JEF-2.2, and JENDL-3 Dosimetry, have recently been made available to the dosimetry community. the Sandia National Laboratories (SNL) Radiation Metrology Laboratory (RML) has worked with these libraries since pre-release versions were available. this paper summarizes the results of the intercomparison and testing of dosimetry cross sections. As a result of this analysis, a compendium of the best dosimetry cross sections was assembled from the available libraries for use within the SNL RML. this library, referred to as the SNLRML Library, contains 66 general dosimetry sensors and 3 special dosimeters unique to the RML sensor inventory. The SNLRML cross sections have been put into a format compatible with commonly used spectrum determination codes

Capture cross sections on unstable nuclei

Directory of Open Access Journals (Sweden)

Tonchev A.P.

2017-01-01

Full Text Available Accurate neutron-capture cross sections on unstable nuclei near the line of beta stability are crucial for understanding the s-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining the most relevant observables that can constrain Hauser-Feshbach statistical-model calculations of capture cross sections. Specifically, we will consider photon scattering using monoenergetic and 100% linearly polarized photon beams. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes near and far from stability will be discussed.

Graphs of the cross sections in the Alternate Monte Carlo Cross Section library at the Los Alamos Scientific Laboratory

International Nuclear Information System (INIS)

Seamon, R.E.; Soran, P.D.

1980-06-01

Graphs of all neutron cross sections and photon production cross sections on the Alternate Monte Carlo Cross Section (AMCCS) library have been plotted along with local neutron heating numbers. The values of ν-bar, the average number of neutrons per fission, are also plotted for appropriate isotopes

Neutron-capture Cross Sections from Indirect Measurements

Energy Technology Data Exchange (ETDEWEB)

Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J

2011-10-18

Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

Constraints on the dark matter annihilation from Fermi-LAT observation of M31

Energy Technology Data Exchange (ETDEWEB)

Li, Zhengwei; Yuan, Qiang [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing, 210008 (China); Huang, Xiaoyuan [Physik-Department T30d, Technische Universität München, James-Franck-Straße, Garching, D-85748 Germany (Germany); Xu, Yupeng, E-mail: lizw@ihep.ac.cn, E-mail: huangxiaoyuan@gmail.com, E-mail: yuanq@pmo.ac.cn, E-mail: xuyp@ihep.ac.cn [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing, 100049 (China)

2016-12-01

Gamma-ray is a good probe of dark matter (DM) particles in the Universe. We search for the DM annihilation signals in the direction of the Andromeda galaxy (M31) using 7.5 year Fermi-LAT pass 8 data. Similar to Pshirkov et al. (2016), we find that there is residual excess emission from the direction of M31 if only the galactic disk as traced by the far infrared emission is considered. Adding a point-like source will improve the fitting effectively, although additional slight improvements can be found if an extended component such as a uniform disk or two bubbles is added instead. Taking the far infrared disk plus a point source as the background model, we search for the DM annihilation signals in the data. We find that there is strong degeneracy between the emission from the galaxy and that from 10s GeV mass DM annihilation in the main halo with quark final state. However, the required DM annihilation cross section is about 10{sup −25}–10{sup −24} cm{sup 3}s{sup −1}, orders of magnitude larger than the constraints from observations of dwarf spheroidal galaxies, indicating a non-DM origin of the emission. If DM subhalos are taken into account, the degeneracy is broken. When considering the enhancement from DM subhalos, the constraints on DM model parameters are comparable to (or slightly weaker than) those from the population of dwarf spheroidal galaxies. We also discuss the inverse Compton scattering component from DM annihilation induced electrons/positrons. For the first time we include an energy dependent template of the inverse Compton emission (i.e., a template cube) in the data analysis to take into account the effect of diffusion of charged particles. We find a significant improvement of the constraints in the high mass range of DM particles after considering the inverse Compton emission.

ENDF/B-IV representation of the 238U total neutron cross section in the resolved resonance energy region

International Nuclear Information System (INIS)

de Saussure, G.; Olsen, D.K.; Perez, R.B.

1976-01-01

The ENDF/B-IV prescription fails to represent correctly the 238 U total (and scattering) cross section between the levels of the resolved range. It is shown how this representation can be improved by properly accounting for the contribution of levels outside the resolved region to the cross section at energies inside the resolved region, and by substituting the more precise multilevel Breit-Wigner formula for the presently used single-level formula. The importance of computing accurately the minima in the total cross section is illustrated by comparing values of the self-shielded capture resonance integral computed with ENDF/B-IV and with a more accurate cross section model

Atlas of photoneutron cross sections obtained with monoenergetic photons

International Nuclear Information System (INIS)

Dietrich, S.S.; Berman, B.L.

1988-01-01

Photoneutron cross-section and integrated cross-section data obtained with monoenergetic photons are presented in a uniform format. All of the measured partial photoneutron cross sections, the total photoneutron cross section, and the photoneutron yield cross section are plotted as functions of the incident photon energy, as are the integrated photoneutron cross sections and their first and second moments. The values of the integrated cross sections and the moments of the integrated total cross section up to the highest photon energy for which they were measured are tabulated, as are the parameters of Lorentz curves fitted to the total photoneutron cross-section data for medium and heavy nuclei (A>50). This compilation is current as of June 1987. copyright 1988 Academic Press, Inc

Clinical characteristics in schizophrenia patients with or without suicide attempts and non-suicidal self-harm--a cross-sectional study.

Science.gov (United States)

Mork, Erlend; Walby, Fredrik A; Harkavy-Friedman, Jill M; Barrett, Elizabeth A; Steen, Nils E; Lorentzen, Steinar; Andreassen, Ole A; Melle, Ingrid; Mehlum, Lars

2013-10-09

To investigate whether schizophrenia patients with both suicide attempts and non-suicidal self-harm have earlier age of onset of psychotic and depressive symptoms and higher levels of clinical symptoms compared to patients with only suicide attempts or without suicide attempt. Using a cross-sectional design, 251 patients (18-61 years old, 58% men) with schizophrenia treated at hospitals in Oslo and Innlandet Hospital Trust, Norway, were assessed with a comprehensive clinical research protocol and divided into three groups based on their history of suicide attempts and non-suicidal self-harm. Suicide attempts were present in 88 patients (35%); 52 had suicide attempts only (29%) and 36 had both suicide attempts and non-suicidal self-harm (14%). When compared with nonattempters and those with suicide attempts without non-suicidal self-harm, patients with both suicide attempts and non-suicidal self-harm were more frequently women, younger at the onset of psychotic symptoms, had longer duration of untreated psychosis, and had higher levels of current impulsivity/aggression and depression. Patients with both suicide attempts and non-suicidal self-harm were more likely to repeat suicide attempts than patients with suicide attempts only. Patients with both suicide attempts and non-suicidal self-harm had different illness history and clinical characteristics compared to patients with only suicide attempts or patients without suicidal behavior. Our study suggests that patients with both suicide attempts and non-suicidal self-harm represent a distinct subgroup among patients with schizophrenia and suicidal behavior with their early onset of psychotic symptoms, high rate of repeated suicidal behavior and significant treatment delay.

Self-management support for chronic pain in primary care: a cross-sectional study of patient experiences and nursing roles.

Science.gov (United States)

Lukewich, Julia; Mann, Elizabeth; VanDenKerkhof, Elizabeth; Tranmer, Joan

2015-11-01

The aim of this study was to describe chronic pain self-management from the perspective of individuals living with chronic pain in the context of primary care nursing. Self-management is a key chronic pain treatment modality and support for self-managing chronic pain is mainly provided in the context of primary care. Although nurses are optimally suited to facilitate self-management in primary care, there is a need to explore opportunities for optimizing their roles. Two cross-sectional studies. The Chronic Pain Self-Management Survey was conducted in 2011-2012 to explore the epidemiology and self-management of chronic pain in Canadian adults. The questionnaire was distributed to 1504 individuals in Ontario. In 2011, the Primary Care Nursing Roles Survey was distributed to 1911 primary care nurses in Ontario to explore their roles and to determine the extent to which chronic disease management strategies, including support for self-management, were implemented in primary care. Few respondents to the pain survey identified nurses as being the 'most helpful' facilitator of self-management while physicians were most commonly cited. Seventy-six per cent of respondents used medication to manage their chronic pain. Few respondents to the nursing survey worked in practices with specific programmes for individuals with chronic pain. Individuals with chronic pain identified barriers and facilitators to self-managing their pain and nurses identified barriers and facilitators to optimizing their role in primary care. There are several opportunities for primary care practices to facilitate self-management of chronic pain, including the optimization of the primary care nursing role. © 2015 John Wiley & Sons Ltd.

Cross-Sectional Analysis of Longitudinal Mediation Processes.

Science.gov (United States)

O'Laughlin, Kristine D; Martin, Monica J; Ferrer, Emilio

2018-01-01

Statistical mediation analysis can help to identify and explain the mechanisms behind psychological processes. Examining a set of variables for mediation effects is a ubiquitous process in the social sciences literature; however, despite evidence suggesting that cross-sectional data can misrepresent the mediation of longitudinal processes, cross-sectional analyses continue to be used in this manner. Alternative longitudinal mediation models, including those rooted in a structural equation modeling framework (cross-lagged panel, latent growth curve, and latent difference score models) are currently available and may provide a better representation of mediation processes for longitudinal data. The purpose of this paper is twofold: first, we provide a comparison of cross-sectional and longitudinal mediation models; second, we advocate using models to evaluate mediation effects that capture the temporal sequence of the process under study. Two separate empirical examples are presented to illustrate differences in the conclusions drawn from cross-sectional and longitudinal mediation analyses. Findings from these examples yielded substantial differences in interpretations between the cross-sectional and longitudinal mediation models considered here. Based on these observations, researchers should use caution when attempting to use cross-sectional data in place of longitudinal data for mediation analyses.

Antideuteron annihilation on nuclei

International Nuclear Information System (INIS)

Cugnon, J.

1992-01-01

An investigation of antideuteron annihilation on nuclei within an intranuclear cascade (INC) model is presented. Two models are set up to describe the annihilation itself, which either implies the antideuteron as a whole and occurs at a single point, or which may be considered as two independent nucleon-antinucleon annihilation occurring at different points and different times. Particular attention is paid to the energy transferred from the pions issued from the annihilation to the nuclear system and to the possibility of having a multifragmentation of the target. The latter feature is investigated within a percolation model. The pion distribution and the energy distribution are also discussed. Predictions of proton multiplicity distributions are compared with experiment. (orig.)

Parametric equations for calculation of macroscopic cross sections

International Nuclear Information System (INIS)

Botelho, Mario Hugo; Carvalho, Fernando

2015-01-01

Neutronic calculations of the core of a nuclear reactor is one thing necessary and important for the design and management of a nuclear reactor in order to prevent accidents and control the reactor efficiently as possible. To perform these calculations a library of nuclear data, including cross sections is required. Currently, to obtain a cross section computer codes are used, which require a large amount of processing time and computer memory. This paper proposes the calculation of macroscopic cross section through the development of parametric equations. The paper illustrates the proposal for the case of macroscopic cross sections of absorption (Σa), which was chosen due to its greater complexity among other cross sections. Parametric equations created enable, quick and dynamic way, the determination of absorption cross sections, enabling the use of them in calculations of reactors. The results show efficient when compared with the absorption cross sections obtained by the ALPHA 8.8.1 code. The differences between the cross sections are less than 2% for group 2 and less than 0.60% for group 1. (author)

Contribution of the two-photon annihilation process in the measurement of σ/sub t/ (e+e/sup /minus// → hadrons at PEP)

International Nuclear Information System (INIS)

Shen, B.

1988-01-01

The possible impact of the 2γ process e/sup /plus//e/sup/minus// → e/sup /plus//e/sup /minus// /plus/ hadrons is evaluated as a source of background for the study of the one photon annihilation process. Two regions of hadron system invariant mass are considered---the resonance region with low invariant mass, and the ''diffractive'' region above 2 GeV hadron invariant mass. In spite of the fact that the 2γ cross-section rises with the energy of the initial e/sup /plus//e/sup /minus// system, it seems clear that measurements of the total energy of the final hadron system will allow the clean separation of the 2γ events from the single photon annihilation reaction

Suicidality, self-stigma, social anxiety and personality traits in stabilized schizophrenia patients – a cross-sectional study

Directory of Open Access Journals (Sweden)

Vrbova K

2018-06-01

Full Text Available Kristyna Vrbova,1,2 Jan Prasko,1–3 Marie Ociskova,1,2 Michaela Holubova,4 Krystof Kantor,1,2 Antonin Kolek,1,2 Aleš Grambal,1,2 Milos Slepecky3 1Department of Psychiatry, University Hospital Olomouc, Olomouc, Czech Republic; 2Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic; 3Department of Psychology Sciences, Faculty of Social Science and Health Care, Constantine the Philosopher University in Nitra, Nitra, Slovak Republic; 4Department of Psychiatry, Hospital Liberec, Liberec, Czech Republic Background and aim: Patients who have schizophrenia are more prone to suicidal behavior than the general population. This study aimed to find connections between suicidality and self-stigma, hope, and personality traits in patients with schizophrenia. Methods: Forty-eight stabilized outpatients with schizophrenia attended this cross-sectional study. Patients were diagnosed by the Mini International Neuropsychiatric Interview (MINI using the ICD-10 research diagnostic criteria. The assessments included Positive and Negative Syndrome Scale, objective and subjective Clinical Global Impression, Liebowitz Social Anxiety Scale, Beck Depression Inventory-second edition, Internalized Stigma of Mental Illness, the Temperament and Character Inventory, and Adult Dispositional Hope Scale. Results: The individual rate of suicidality (suicidal index from MINI strongly positively correlated with self-stigma, level of depression, social anxiety, and harm-avoidance, and negatively correlated with hope, self-directedness, and stigma resistance. Conclusion: Individuals with additional symptoms of depression, social anxiety, trait-like anxiety, and self-stigma should be carefully monitored for suicidal ideation. On the opposite side, patients with sufficient hope, self-esteem, and goal-directed attitudes are less likely to have suicidal thoughts and may potentially be role models in group rehabilitation programs, motivating more

Low Energy Neutrino Cross Sections

International Nuclear Information System (INIS)

Zeller, G.P.

2004-01-01

Present atmospheric and accelerator based neutrino oscillation experiments operate at low neutrino energies (Ev ∼ 1 GeV) to access the relevant regions of oscillation parameter space. As such, they require precise knowledge of the cross sections for neutrino-nucleon interactions in the sub-to-few GeV range. At these energies, neutrinos predominantly interact via quasi-elastic (QE) or single pion production processes, which historically have not been as well studied as the deep inelastic scattering reactions that dominate at higher energies.Data on low energy neutrino cross sections come mainly from bubble chamber, spark chamber, and emulsion experiments that collected their data decades ago. Despite relatively poor statistics and large neutrino flux uncertainties, these measurements provide an important and necessary constraint on Monte Carlo models in present use. The following sections discuss the current status of QE, resonant single pion, coherent pion, and single kaon production cross section measurements at low energy

Group cross-section processing method and common nuclear group cross-section library based on JENDL-3 nuclear data file

International Nuclear Information System (INIS)

Hasegawa, Akira

1991-01-01

A common group cross-section library has been developed in JAERI. This system is called 'JSSTDL-295n-104γ (neutron:295 gamma:104) group constants library system', which is composed of a common 295n-104γ group cross-section library based on JENDL-3 nuclear data file and its utility codes. This system is applicable to fast and fusion reactors. In this paper, firstly outline of group cross-section processing adopted in Prof. GROUCH-G/B system is described in detail which is a common step for all group cross-section library generation. Next available group cross-section libraries developed in Japan based on JENDL-3 are briefly reviewed. Lastly newly developed JSSTDL library system is presented with some special attention to the JENDL-3 data. (author)

Neutron-capture cross sections from indirect measurements

Directory of Open Access Journals (Sweden)

Scielzo N.D.

2012-02-01

Full Text Available Cross sections for compound-nuclear reactions reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f reactions, but need to be improved upon for applications to capture reactions.

Curves and tables of neutron cross sections

International Nuclear Information System (INIS)

Nakagawa, Tsuneo; Asami, Tetsuo; Yoshida, Tadashi

1990-07-01

Neutron cross-section curves from the Japanese Evaluated Nuclear Data Library version 3, JENDL-3, are presented in both graphical and tabular form for users in a wide range of application areas in the nuclear energy field. The contents cover cross sections for all the main reactions induced by neutrons with an energy below 20 MeV including; total, elastic scattering, capture, and fission, (n,n'), (n,2n), (n,3n), (n,α), (n,p) reactions. The 2200 m/s cross-section values, resonance integrals, and Maxwellian- and fission-spectrum averaged cross sections are also tabulated. (author)

Development of Indian cross section data files for Th-232 and U-233 and integral validation studies

International Nuclear Information System (INIS)

Ganesan, S.

1988-01-01

This paper presents an overview of the tasks performed towards the development of Indian cross section data files for Th-232 and U-233. Discrepancies in various neutron induced reaction cross sections in various available evaluated data files have been obtained by processing the basic data into multigroup form and intercomparison of the latter. Interesting results of integral validation studies for capture, fission and (n,2n) cross sections for Th-232 by analyses of selected integral measurements are presented. In the resonance range, energy regions where significant differences in the calculated self-shielding factors for Th-232 occur have been identified by a comparison of self-shielded multigroup cross sections derived from two recent evaluated data files, viz., ENDF/B-V (Rev.2) and JENDL-2, for several dilutions and temperatures. For U-233, the three different basic data files ENDF/B-IV, JENDL-2 and ENDL-84 were intercompared. Interesting observations on the predictional capability of these files for the criticality of the spherical metal U-233 system are given. The current status of Indian data file is presented. (author) 62 ref

Self-Reported Poor Work Ability--An Indicator of Need for Rehabilitation? A Cross-Sectional Study of a Sample of German Employees.

Science.gov (United States)

Bethge, Matthias; Spanier, Katja; Neugebauer, Tjark; Mohnberg, Inka; Radoschewski, Friedrich Michael

2015-11-01

The purpose of this study was to assess associations of self-reported work ability as measured by the Work Ability Index (WAI) with modifiable behavioral and occupational health risks, health service utilization, and intended rehabilitation and pension requests. This is a cross-sectional study of a random sample of German employees aged 40-54 yrs on sickness benefits in 2012 (trial registration: DRKS00004824). In total, 1312 male and 1502 female employees were included in the analyses. Low WAI scores (i.e., work strategies, which include the opportunity to access multiprofessional rehabilitation.

Theory of neutron resonance cross sections for safety applications

International Nuclear Information System (INIS)

Froehner, F.H.

1992-09-01

Neutron resonances exert a strong influence on the behaviour of nuclear reactors, especially on their response to the temperature changes accompanying power excursions, and also on the efficiency of shielding materials. The relevant theory of neutron resonance cross sections including the practically important approximations is reviewed, both for the resolved and the unresolved resonance region. Numerical techniques for Doppler broadening of resonances are presented, and the construction of group constants and especially of self-shielding factors for neutronics calculations is outlined. (orig.) [de

Neutron Cross Sections for Aluminium

Energy Technology Data Exchange (ETDEWEB)

Forsberg, Leif

1963-08-15

Total, elastic, inelastic, (n, 2n), (n, {alpha}), (n, p), and (n, {gamma}) cross sections for aluminium have been compiled from thermal to 100 MeV based upon literature search and theoretical interpolations and estimates. Differential elastic cross sections in the centre of mass system are represented by the Legendre coefficients. This method was chosen in order to obtain the best description of the energy dependence of the anisotropy.

High ET jet cross sections at CDF

International Nuclear Information System (INIS)

Flaugher, B.

1996-08-01

The inclusive jet cross section for p anti p collisions at √s = 1.8 TeV as measured by the CDF collaboration will be presented. Preliminary CDF measurements of the Σ E T cross section at √s = 1.8 TeV and the central inclusive jet cross section at √s = 0.630 TeV will also be shown

Microscopic description of production cross sections including deexcitation effects

Science.gov (United States)

Sekizawa, Kazuyuki

2017-07-01

results. However, there remain discrepancies between the measurements and the calculated cross sections, indicating a limit of the theoretical framework that works with a single mean-field potential. Possible causes of the discrepancies are discussed. Conclusions: To perfectly reproduce experimental cross sections for multinucleon transfer processes, one should go beyond the standard self-consistent mean-field description. Nevertheless, the proposed method will provide valuable information to optimize production mechanisms of new neutron-rich nuclei through its microscopic, nonempirical predictions.

Quality of life, self-stigma, and hope in schizophrenia spectrum disorders: a cross-sectional study

Directory of Open Access Journals (Sweden)

Vrbova K

2017-02-01

Full Text Available Kristyna Vrbova,1 Jan Prasko,1 Marie Ociskova,1 Dana Kamaradova,1 Marketa Marackova,1 Michaela Holubova,1,2 Ales Grambal,1 Milos Slepecky,3 Klara Latalova1 1Department of Psychiatry, Faculty of Medicine and Dentistry, University Palacky Olomouc, University Hospital Olomouc, Olomouc, 2Department of Psychiatry, Hospital Liberec, Liberec, Czech Republic; 3Department of Psychology Sciences, Faculty of Social Science and Health Care, Constantine the Philosopher University in Nitra, Nitra, Slovakia Goals: The aim of this study was to explore the quality of life, self-stigma, personality traits, and hope in patients with schizophrenia spectrum disorders. Patients and methods: A total of 52 outpatients participated in this cross-sectional study. The attending psychiatrist assessed each patient with Mini International Neuropsychiatric Interview (MINI. The patients then completed Quality of Life Satisfaction and Enjoyment Questionnaire (Q-LES-Q, Internalized Stigma of Mental Illness (ISMI Scale, Temperament and Character Inventory – Revised (TCI-R, Adult Dispositional Hope Scale (ADHS, Drug Attitude Inventory 10 (DAI-10, and Liebowitz Social Anxiety Scale (LSAS-Self-report. The psychiatrist evaluated Clinical Global Impression Severity – the objective version (objCGI-S, and the patients completed the Clinical Global Impression Severity – the subjective version (subjCGI-S. Each participant also completed Beck Depression Inventory-II (BDI-II, and Beck Anxiety Inventory (BAI.Results: The quality of life was significantly higher in employed patients and individuals with higher hope, self-directedness (SD, and persistence (PS. The quality of life was lower among patients with higher number of psychiatric hospitalizations, those with higher severity of the disorder, and individuals who were taking higher doses of antipsychotics. Patients with more pronounced symptoms of depression, anxiety, and social anxiety had a lower quality of life. Finally, the

The evolving professional nursing self-image of students in baccalaureate programs: a cross-sectional survey.

Science.gov (United States)

Milisen, Koen; De Busser, Tinne; Kayaert, Annelore; Abraham, Ivo; de Casterlé, Bernadette Dierckx

2010-06-01

We have previously examined the professional self-image of practicing nurses in Belgium and its association with various professional decisions, however there is limited knowledge about the professional self-image of nurses-to-be. Despite prior research on nursing students' perceptions of nursing or their self-esteem, students' professional image, defined as "the way students perceive themselves in their clinical practice environment and their anticipated work environment", has not been described nor compared to that of practicing nurses. To describe the professional nursing self-image among students in their final year of baccalaureate education. Cross-sectional survey. Nine geographically spread baccalaureate programs in the Flemish region of Belgium. 427 evaluable students from 455 recruited from 663 potential. Data collected in each school during regular hours using an adapted version of the BELIMAGE (Belgian professional self-image instrument for hospital nurses) including questions on personal demographics, education and competence, nursing care, team and practice environment. Voluntary participation with returned questionnaire deemed informed consent. Respondents identified several curricular components as contributing to their perceived competence. They also identified several skills deemed important to professional nursing, however did not feel competent in all of these. Important nursing care aspects included individualizing patient care, detecting care problems and potential complications, and promoting patient well-being; within a care environment with open interdisciplinary communication, where care problems could be discussed with nursing colleagues, where one cares for the same patient regularly, and led by a team leader with vision. Society's view of nursing was generally more negative than students'. Most students planned on working in nursing after their studies and many had thought about additional education at some point. Most were proud of

Cross-sectional study of self-reported ADHD symptoms and psychological comorbidity among college students in Chandigarh, India.

Science.gov (United States)

Jhambh, Ishani; Arun, Priti; Garg, Jasmin

2014-01-01

Existence of attention deficit hyperactivity disorder (ADHD) in adults is scantily researched in India. There is dearth of information on prevalence of ADHD in college students worldwide. Further, fewer studies in the past have evaluated the impact of ADHD on the psychological well-being of college students. To study the prevalence of ADHD among college students and psychological problems related to ADHD. Cross-sectional study. A total of 237 students were recruited from various medical, engineering, and commerce and arts colleges of Chandigarh, India. They were administered the Adult ADHD Self Report Scale v1.1(ASRS) and the Wender Utah Rating Scale (WURS) to diagnose adult ADHD. To assess comorbidities; General Health Questionnaire-12 (GHQ); Zung Depression Rating Scale (ZDRS); Rosenberg's Self-Esteem Scale (RSES);and questions on emotional stability, social problems, and substance use (alcohol, tobacco, and cannabis) were administered on all participants. A total of 13 students (5.48%) fulfilled the criteria for adult ADHD. These students experienced significantly higher emotional instability and low self-esteem than those without ADHD (N = 224). The occurrence of psychological problems, depression, social problems, and substance abuse was comparable in students with and without ADHD. ADHD is prevalent among the college students studying in the most competitive institutes as well. Students with ADHD experience higher emotional instability and poor self-esteem than others. It has little effect on their psychological well-being and social adjustment. Prompt detection and management of ADHD in college students may help them deal with these problems effectively.

Cross-sectional study of self-reported ADHD symptoms and psychological comorbidity among college students in Chandigarh, India

Directory of Open Access Journals (Sweden)

Ishani Jhambh

2014-01-01

Full Text Available Background: Existence of attention deficit hyperactivity disorder (ADHD in adults is scantily researched in India. There is dearth of information on prevalence of ADHD in college students worldwide. Further, fewer studies in the past have evaluated the impact of ADHD on the psychological well-being of college students. Aims: To study the prevalence of ADHD among college students and psychological problems related to ADHD. Design: Cross-sectional study. Subjects and Methods: A total of 237 students were recruited from various medical, engineering, and commerce and arts colleges of Chandigarh, India. They were administered the Adult ADHD Self Report Scale v1.1(ASRS and the Wender Utah Rating Scale (WURS to diagnose adult ADHD. To assess comorbidities; General Health Questionnaire-12 (GHQ; Zung Depression Rating Scale (ZDRS; Rosenberg′s Self-Esteem Scale (RSES;and questions on emotional stability, social problems, and substance use (alcohol, tobacco, and cannabis were administered on all participants. Results: A total of 13 students (5.48% fulfilled the criteria for adult ADHD. These students experienced significantly higher emotional instability and low self-esteem than those without ADHD (N = 224. The occurrence of psychological problems, depression, social problems, and substance abuse was comparable in students with and without ADHD. Conclusions: ADHD is prevalent among the college students studying in the most competitive institutes as well. Students with ADHD experience higher emotional instability and poor self-esteem than others. It has little effect on their psychological well-being and social adjustment. Prompt detection and management of ADHD in college students may help them deal with these problems effectively.

Evaluation of epoxy resin for cryogenic use by positron annihilation method. Change of characteristics of epoxy resin with cross-linking density and positron lifetime

International Nuclear Information System (INIS)

Nishijima, Shigehiro; Honda, Yoshihide; Okada, Toichi; Kobayashi, Yoshinori; Namba, Shingo.

1994-01-01

The positron annihilation method has been applied to evaluate unoccupied space in epoxy aiming at the design of the molecular structure for cryogenic use. To confirm the model in which molecular free space is needed in the epoxy for cryogenic use, the molecular weight between cross-linkings in epoxy was changed. The increase of molecular weight between cross-linkings brought an increase of fracture toughness even at liquid helium temperature and the model was found to be confirmed. The increase of molecular weight between cross-linkings was also found to decrease the 3rd lifetime of positrons. It suggested that the epoxy main chains were folded and this was confirmed by the molecular mechanical calculation. (author)

Criticality studies of fast assemblies with the new 27-group cross-section set

International Nuclear Information System (INIS)

Garg, S.B.; Shukla, V.K.

1976-01-01

A test of 27-group cross-section set (Garg-set) recently derived from ENDF/B library has been carried out in the criticality studies of the Pu 239 , U 235 and U 233 based metal, oxide and carbide fuelled fast critical assemblies. A total of twenty fast critical assemblies of different sizes and varying neutron spectra have been selected for analysis. Based on these analyses it has been observed that the Garg-set predicts well the criticality of uranium and plutonium based hard-spectra assemblies. In the soft-spectra systems it underpredicts criticality because of the following reasons: (a) It makes use of the higher capture cross-sections of structural and coolant elements given in ENDF/B - Version IV library. (b) It does not account for the resonance self-shielding effects of cross-sections. It has also been observed that the Garg-set gives better results than the MABBN-set for dense and dilute plutonium-based and the hard uranium-based assemblies. This superior trend of the Garg-set is slightly lost in the uranium-based dilute systems because of large differences in the capture cross-sections of structural elements of these two sets. (author)

Recommended evaluation procedure for photonuclear cross section

Energy Technology Data Exchange (ETDEWEB)

Lee, Young-Ouk; Chang, Jonghwa; Fukahori, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-03-01

In order to generate photonuclear cross section library for the necessary applications, data evaluation is combined with theoretical evaluation, since photonuclear cross sections measured cannot provide all necessary data. This report recommends a procedure consisting of four steps: (1) analysis of experimental data, (2) data evaluation, (3) theoretical evaluation and, if necessary, (4) modification of results. In the stage of analysis, data obtained by different measurements are reprocessed through the analysis of their discrepancies to a representative data set. In the data evaluation, photonuclear absorption cross sections are evaluated via giant dipole resonance and quasi-deutron mechanism. With photoabsorption cross sections from the data evaluation, theoretical evaluation is applied to determine various decay channel cross sections and emission spectra using equilibrium and preequilibrium mechanism. After this, the calculated results are compared with measured data, and in some cases the results are modified to better describe measurements. (author)

Recommended activation detector cross sections (RNDL-82)

International Nuclear Information System (INIS)

Bondars, Kh.Ya.; Lapenas, A.A.

1984-01-01

The results of the comparison between measured and calculated average cross sections in 5 benchmark experiments are presented. Calculations have been based on the data from 10 libraries of evaluated cross sections. The recommended library (RNDL-82) of the activation detector cross sections has been created on the basis of the comparison. RNDL-82, including 26 reactions, and the basic characteristics of the detectors are presented. (author)

Activation cross section and isomeric cross section ratios for the (n ,2 n ) reaction on 153Eu

Science.gov (United States)

Luo, Junhua; Jiang, Li; Li, Suyuan

2017-10-01

The 153Eu(n ,2 n ) m1,m2,g152Eu cross section was measured by means of the activation technique at three neutron energies in the range 13-15 MeV. The quasimonoenergetic neutron beam was formed via the 3H(d ,n ) 4He reaction, in the Pd-300 Neutron Generator at the Chinese Academy of Engineering Physics (CAEP). The activities induced in the reaction products were measured using high-resolution γ-ray spectroscopy. The cross section of the population of the second high-spin (8-) isomeric state was measured along with the reaction cross section populating both the ground (3-) and the first isomeric state (0-). Cross sections were also evaluated theoretically using the numerical code TALYS-1.8, with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature.

Smartphone application for rheumatoid arthritis self-management: cross-sectional study revealed the usefulness, willingness to use and patients' needs.

Science.gov (United States)

Azevedo, Rita; Bernardes, Miguel; Fonseca, João; Lima, Aurea

2015-10-01

Patient-centered smartphone applications have potential to support rheumatoid arthritis (RA) self-management but remain almost unexplored in literature. Therefore, this study evaluated the usefulness of a smartphone application to support RA self-management, the willingness of RA patients to use and pay for it and the features the application should have. In this cross-sectional study, a questionnaire was developed to collect information on population, device ownership, usefulness and willingness to use and pay for a RA self-management application and application features. Descriptive statistics, Chi-square, Fisher's exact test, t test or Mann-Whitney's test and multivariate analysis were used. One hundred RA patients answered the questionnaire. Patients' mean age was 57 ± 11.9 years, most were females (91 %), with multiple drug regimens and a 40 % treatment non-compliance rate. Most patients believed that could have a more active role in self-management (94 %) and reported it would be useful to develop a RA self-management application (86 %). Patients willing to use an application (83 %) were younger, with a possible more active role in self-management, with access to a smartphone, and using short message service, electronic mail and Internet. Multivariate analysis confirmed these results, except the associations regarding access to a smartphone and use of electronic mail and Internet. Fifty-eight patients (82 %) were willing to pay for a RA self-management application and the most requested feature for it was information in a simple format. This study suggested the usefulness and patients' willingness to use and pay for a RA self-management application and provided insight on patients' needs.

Activation cross section and isomeric cross-section ratio for the (n,2n) reaction on {sup 132,134}Ba

Energy Technology Data Exchange (ETDEWEB)

Luo, Junhua [Hexi Univ., Zhangye (China). School of Physics and Electromechanical Engineering; Hexi Univ., Zhangye (China). Inst. of New Energy; Wu, Chunlei; Jiang, Li [Chinese Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry; Li, Suyuan [Hexi Univ., Zhangye (China). Inst. of New Energy

2017-07-01

Cross sections of the {sup 132}Ba(n,2n){sup 131m,g}Ba and {sup 134}Ba(n,2n){sup 133m,g}Ba reactions and their isomeric cross section ratios σ{sub m}/σ{sub g} have been measured by means of the activation technique at three neutron energies in the range 13-15 MeV. BaCO{sub 3} samples and Nb monitor foils were activated together to determine the reaction cross section and the incident neutron flux. The quasimonoenergetic neutrons beam were produced via the {sup 3}H(d,n){sup 4}He reaction at the Pd-300 Neutron Generator of the Chinese Academy of Engineering Physics (CAEP). The activities induced in the reaction products were measured using high-resolution γ ray spectroscopy. The pure cross section of the ground-state was derived from the absolute cross section of the metastable state and the residual nuclear decay analysis. Cross sections were also evaluated theoretically using the numerical nuclear model code, TALYS-1.8 with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature.

Self-Concept and Self-Esteem: A Cross-Cultural Perspective.

Science.gov (United States)

Wood, Melinda

1991-01-01

Describes issues of self-concept and self-esteem that arise when people find themselves living in a cross-cultural environment. Discusses Western definition of self-concept and other self-concept models. Discusses self-esteem and integration and adjustment as it relates to bicultural persons. (ABL)

Dielectronic recombination cross sections for H-like ions

International Nuclear Information System (INIS)

Pindzola, M.S.; Badnell, N.R.; Griffin, D.C.

1990-01-01

Dielectronic recombination cross sections for several H-like atomic ions are calculated in an isolated-resonance, distorted-wave approximation. Fine-structure and configuration-interaction effects are examined in detail for the O 7+ cross section. Hartree-Fock, intermediate-coupled, multiconfiguration dielectronic recombination cross sections for O 7+ are then compared with the recent experimental measurements obtained with the Test Storage Ring in Heidelberg. The cross-section spectra line up well in energy and the shape of the main resonance structures are comparable. The experimental integrated cross sections differ by up to 20% from theory, but this may be due in part to uncertainties in the electron distribution function

Comparative analysis among several cross section sets