Mostrando recursos 1 - 9 de 9

  1. Exploration of new methods for Lattice QCD

    Rios Tascon, Andres
    We explore two methods aimed at alleviating two difficulties in Lattice QCD: statistical noise and data storage. The first method intends to improve the signal-to-noise (S/N) ratio in three-point correlators, by extending previous work by Detmold and Endres. We test the method in the measurement of two observables: the nucleonic axial charge, and a matrix element computation related to the electromagnetic form factor of the rho meson. Only in the case of the rho we see a very slight improvement. We conclude that, in general, a case-by-case study would be needed to determine the effectiveness of the S/N optimization. The...

  2. Exploration of new methods for Lattice QCD

    Rios Tascon, Andres
    We explore two methods aimed at alleviating two difficulties in Lattice QCD: statistical noise and data storage. The first method intends to improve the signal-to-noise (S/N) ratio in three-point correlators, by extending previous work by Detmold and Endres. We test the method in the measurement of two observables: the nucleonic axial charge, and a matrix element computation related to the electromagnetic form factor of the rho meson. Only in the case of the rho we see a very slight improvement. We conclude that, in general, a case-by-case study would be needed to determine the effectiveness of the S/N optimization. The...

  3. General Description of Fission Observables: GEF Model Code

    Schmidt, Karl-Heinz; Jurado, Beatriz; Amouroux, Charlotte; Schmitt, C.
    The GEF (" GEneral description of Fission observables ") model code is documented. It describes the observables for spontaneous fission, neutron-induced fission and, more generally, for fission of a compound nucleus from any other entrance channel, with given excitation energy and angular momentum. The GEF model is applicable for a wide range of isotopes from Z = 80 to Z = 112 and beyond, up to excitation energies of about 100 MeV. The results of the GEF model are compared with fission barriers, fission probabilities, fission-fragment mass-and nuclide distributions, isomeric ratios, total kinetic energies, and prompt-neutron and prompt-gamma yields and...

  4. A new population of very high energy gamma-ray sources in the Milky Way

    Aharonian, F.; G. Akhperjanian, A.; Aye, K.-M.; R. Bazer-Bachi, A.; Beilicke, M.; Benbow, W.; Berge, D.; Berghaus, P.; Bernlöhr, K.; Boisson, C.; Bolz, O.; Borgmeier, C.; Braun, I.; Breitling, F.; M. Brown, A.; Bussons Gordo, J.; M. Chadwick, P.; Chounet, L.-M.; Cornils, R.; Costamante, L.; Degrange, B.; Djannati-Ataï, A.; O'C. Drury, L.; Dubus, G.; Ergin, T.; Espigat, P.; Feinstein, F.; Fleury, P.; Fontaine, G.; Funk, S.; Gallant, Y.A.; Giebels, B.; Gillessen, S.; Goret, P.; Hadjichristidis, C.; Hauser, M.; Heinzelmann, G.; Henri, G.; Hermann, G.; A. Hinton, J.; Hofmann, W.; Holleran, M.; Horns, D.; C. De Jager, O.; Jung, I.; Khélifi, B.; Komin, Nu.; Konopelko, A.; J. Latham, I.; Le Gallou, R.; Lemière, A.; Lemoine, M.; Leroy, N.; Lohse, T.; Marcowith, A.; Masterson, C.; J. L. Mccomb, T.; De Naurois, M.; J. Nolan, S.; Noutsos, A.; J. Orford, K.; L. Osborne, J.; Ouchrif, M.; Panter, M.; Pelletier, G.; Pita, S.; Pühlhofer, G.; Punch, M.; C. Raubenheimer, B.; Raue, M.; Raux, J.; M. Rayner, S.; Redondo, I.; Reimer, A.; Reimer, O.; Ripken, J.; Rob, L.; Rolland, L.; Rowell, G.; Sahakian, V.; Saugé, L.; Schlenker, S.; Schlickeiser, R.; Schuster, C.; Schwanke, U.; Siewert, M.; Sol, H.; Steenkamp, R.; Stegmann, C.; Tavernet, J.-P.; Terrier, R.; Théoret, C.G.; Tluczykont, M.; J. Van Der Walt, D.; Vasileiadis, G.; Venter, C.; Vincent, P.; Visser, B.; J. Völk, H.; J. Wagner, S.
    Very high energy gamma-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first sensitive survey of the inner part of the Milky Way with the High Energy Stereoscopic System (H.E.S.S.) reveals a population of eight previously unknown firmly detected sources of very high energy gamma-rays. At least two have no known radio or X-ray counterpart and may be representative of a new class of `dark' nucleonic cosmic ray sources.

  5. Palliser Rockslide cosmogenic 36Cl exposure ages (raw data) and erosion effect on the cosmogenic

    Sturzenegger, Matthieu; Stead, Doug; Gosse, John; Ward, Brent; Froese, Corey
    This paper presents the results of a combined study, using cosmogenic 36Cl exposure dating and terrestrial digital photogrammetry, of the Palliser Rockslide located in the southeastern Canadian Rocky Mountains. This site is particularly well-suited to demonstrate how this multi-disciplinary approach can be used to differentiate distinct rocksliding events, estimate their volume, and establish their chronology and recurrence interval. Observations suggest that rocksliding has been ongoing since the late Pleistocene deglaciation. Two major rockslide events have been dated at 10.0 ± 1.2 kyr and 7.7 ± 0.8 kyr before present, with failure volumes of 40 Mm3 and 8 Mm3, respectively. The...

  6. Palliser Rockslide cosmogenic 36Cl exposure ages (raw data) and erosion effect on the cosmogenic

    Sturzenegger, Matthieu; Stead, Doug; Gosse, John; Ward, Brent; Froese, Corey
    This paper presents the results of a combined study, using cosmogenic 36Cl exposure dating and terrestrial digital photogrammetry, of the Palliser Rockslide located in the southeastern Canadian Rocky Mountains. This site is particularly well-suited to demonstrate how this multi-disciplinary approach can be used to differentiate distinct rocksliding events, estimate their volume, and establish their chronology and recurrence interval. Observations suggest that rocksliding has been ongoing since the late Pleistocene deglaciation. Two major rockslide events have been dated at 10.0 ± 1.2 kyr and 7.7 ± 0.8 kyr before present, with failure volumes of 40 Mm3 and 8 Mm3, respectively. The...

  7. The reaction D(γp)n at intermediate energies

    Annand, J.R.M.; Anthony, I.; Crawford, G.I.; Dancer, S.N.; Hall, S.J.; Kellie, J.D.; McGeorge, J.C.; McPherson, A.; MacGregor, I.J.D.; Owens, R.O.; Wallace, P.; Schoch, B.; Vogt, J.; Beck, R.; Branford, D.; Springham, S.
    Photodisintegration of the deuteron is an attractive reaction for detailed study since it is susceptible to calculation without approximations necessary in many body problems. The D-> np amplitude is sensitive to the nature of the NN interaction and to non-nucleonic components of the deuteron wavefunction. However, existing measurements of the cross section vary by 40% in the intermediate energy region. We intend to present results of a measurement of the differential cross se for the D(gaamma,p) reaction with an accuracy of +-4% over the energy range 80 to 130 MeV.

  8. Nucleonic intensities investigated during the Atlantic Expedition IQSY 1965 of RV "Meteor" (Appendix)

    Allkofer, Otto Claus; Andresen, R D; Bagge, E; Dau, W D; Funk, H
    The nucleonic component of the cosmic rays has been measured by the German research vessel "Meteor" during the Atlantic Expedition IQSY 1965. The pressure corrected intensities fit well the rigidity calculations of Kondo and Kodamo. In this way we confirm the earth's magnetic field model used by these authors. Two positions of the cosmic ray equator have been determined at 29,7 °W (6,5 ± 1) °N and at 19 °W (7 ± 1) °N. These positions agree with the calculated values of Kondo and Kodamo. The total latitude effect of the nucleonic component amounts to 1.74 and 1.76. The measurements...

  9. Nucleonic intensities investigated during the Atlantic Expedition IQSY 1965 of RV "Meteor" (Appendix)

    Allkofer, Otto Claus; Andresen, R D; Bagge, E; Dau, W D; Funk, H
    The nucleonic component of the cosmic rays has been measured by the German research vessel "Meteor" during the Atlantic Expedition IQSY 1965. The pressure corrected intensities fit well the rigidity calculations of Kondo and Kodamo. In this way we confirm the earth's magnetic field model used by these authors. Two positions of the cosmic ray equator have been determined at 29,7 °W (6,5 ± 1) °N and at 19 °W (7 ± 1) °N. These positions agree with the calculated values of Kondo and Kodamo. The total latitude effect of the nucleonic component amounts to 1.74 and 1.76. The measurements...

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