426 research outputs found

    How do Neutrinos Propagate ? - Wave-Packet Treatment of Neutrino Oscillation

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    The wave-packet treatment of neutrino oscillation developed previously is extended to the case in which momentum distribution functions are taken to be a Gaussian form with both central values and dispersions depending on the mass eigenstates of the neutrinos. It is shown among other things that the velocity of the neutrino wave packets does not in general agree with what one would expect classically and that relativistic neutrinos emitted from pions nevertheless do follow, to a good approximation, the classical trajectory.Comment: 13 page. No figure. Typeset using PTPTeX.st

    Isospin-symmetry breaking in superallowed Fermi beta-decay due to isospin-nonconserving forces

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    We investigate isospin-symmetry breaking effects in the sd-shell region with large-scale shell-model calculations, aiming to understand the recent anomalies observed in superallowed Fermi beta-decay. We begin with calculations of Coulomb displacement energies (CDE's) and triplet displacement energies (TDE's) by adding the T=1,J=0 isospin nonconserving (INC) interaction into the usual isospin-invariant Hamiltonian. It is found that CDE's and TDE's can be systematically described with high accuracy. A total number of 122 one- and two-proton separation energies are predicted accordingly, and locations of the proton drip-line and candidates for proton-emitters are thereby suggested. However, attempt to explain the anomalies in the superallowed Fermi beta-decay fails because these well-fitted T=1,J=0 INC interactions are found no effects on the nuclear matrix elements. It is demonstrated that the observed large isospin-breaking correction in the 32Cl beta-decay, the large isospin-mixing in the 31Cl beta-decay, and the small isospin-mixing in the 23Al beta-decay can be consistently understood by introducing additional T=1,J=2 INC interactions related to the s1/2 orbit.Comment: 7 pages, 3 figures, accepted in Phys. Lett.

    Large mirror asymmetry in Gamow-Teller β-decay in the A = 26 isobaric multiplet

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    We investigate a striking example of mirror asymmetry in Gamow-Teller (GT) β-decay using the nuclear shell-model including isospin-nonconserving (INC) forces in the sd-shell region. We show that the large mirror asymmetry between 26 P and 26 Na GT β-decay can be accurately reproduced by introducing T=1, J≠0 INC forces related to the s 1/2 orbit, while the usual J=0 INC force, commonly adopted to describe isospin-symmetry breaking, does not work. We further show that the calculated distribution of summed GT strength for the 26 P β-decay is in good agreement with the experimental data. Our results support the conclusion that 26 P is a nucleus with proton-halo structure

    Finding abnormal events during the Iraq War monitored at Japan 8000km away from Iraq

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    Department of Earth Sciences, Faculty of Science, Kanazawa UniversityGraduate School of Natural Science and Technology, Kanazawa UniversityMeteorological Research Institute JST Cooperative System for Supporting Priority ResearchMeteorological Research Institute JST Cooperative System for Supporting Priority ResearchGraduate School of Natural Science and Technology, Kanazawa UniversityGraduate School of Natural Science and Technology, Kanazawa UniversityGraduate School of Natural Science and Technology, Kanazawa UniversityUnusual strong acidic rain recorded during the Iraq War in Japan Sea side 8000km away from Iraq. In order to monitor the seasonal change of pH, the rainwater was collected during the period from March 24th to September 24th, 2003 at Kanazawa, Ishikawa Prefecture, Japan. For comparison, the rainwater at Wakayama (the Pacific Ocean side) was collected, during the period from March 24th to April 30th, 2003. The pH, Eh, EC, and DO of the rainwater were measured in laboratory periodically. Filtered rain dusts were investigated by scanning electron microscope equipped with energy dispersive X-ray spectrometer (SEM-EDX), electron probe micro analyzer (EPMA), transmission electron microscope (TEM), energy dispersive X-ray fluorescence spectrometer (ED-XRF), and X-ray powder diffraction (XRD) analyses. In this study, the fluctuation of pH values and electrical conductivity (EC) of rainwater during this half-year period were measured to find abnormal events, such as the Iraq War effects. Since March 21st, 2003, Iraq plunged into the war. The more than 30 oil field fires in Rumaylah, Basrah, Mosul, and other oil fields near the borderline of Kuwait and Iran were reported in March and in April, 2003 in Japan. The first precipitation during the Iraq War was caught on March 24th, 2003. In the period from March 24th to April 5th, the notable low pH value of 3.4-4.4 and high EC value of 20-360ƒハS/cm were detected in Kanazawa. The acidic rain associated with WNW wind (2.7-4.1m/s) has continued to the first 10 days of April in Kanazawa, during the 9 oil fields were burning in Rumaylah, Iraq. In the same time, the upper current of air maps confirmed that the 5520-5700m lines cross over and spread on both Iraq and Japanese Honshu Island. It is considered that westerly wind crossed over both Iraq and Japan. The high EC values from March 24th to April 5th, 2003, suggest that high concentrations of water-soluble carbon particles and soot contained in the rainwater. In addition, the black powdery dusts were detected from the strong acidic rainwater on April 1st. The powdery dusts and carbon-bearing particles contained in the rainwater have characteristics different from that of the Asian aerosol particles (Kosa). The results suggest that both powdery dusts and carbon-bearing particles of rainwater have been produced by combustion of oil field in Iraq. Simulation data support the directly cycling by westerly wind indicating the influence of the Iraq War. Possible evidences provided in this paper, such as strong acidic rain and high EC values with nm-sized carbon soot at lapan Sea side, was the influence of the Iraq War. It was suggested that local events affect the global atmospheric environments. Smoke from oil field fires around Baghdad and other wartime pollution could create long-term health hazards
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