2,006 research outputs found

    An FFAG Transport Line for the PAMELA Project

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    The PAMELA project to design an accelerator for hadron therapy using non-scaling Fixed Field Alternating Gradient (NS-FFAG) magnets requires a transport line and gantry to take the beam to the patient. The NS-FFAG principle offers the possibility of a gantry much smaller, lighter and cheaper than conventional designs, with the added ability to accept a wide range of fast changing energies. This paper will build on previous work to investigate a transport line which could be used for the PAMELA project. The design is presented along with a study and optimisation of its acceptance

    Spectral-Function Sum Rules in Supersymmetry Breaking Models

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    The technique of Weinberg's spectral-function sum rule is a powerful tool for a study of models in which global symmetry is dynamically broken. It enables us to convert information on the short-distance behavior of a theory to relations among physical quantities which appear in the low-energy picture of the theory. We apply such technique to general supersymmetry breaking models to derive new sum rules.Comment: 18 pages, 1 figur

    Anomalous Nernst Effect in Nonmagnetic Nodal Line Semimetal PbTaSe2_2

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    PbTaSe2_2 is a unique topological material, in which the number of nodal lines is expected to change at the structural transition between the lower temperature/pressure "L" phase and the higher temperature/pressure "H" phase. We report the anomalous Nernst effect attributed to the Berry curvature of nodal lines and its change with the structural transition. In the L phase, the Nernst coefficient (SyxS_{yx}) shows the step-like magnetic field dependence reminiscent of the anomalous Nernst effect of nonmagnetic Dirac/Weyl semimetals. By applying hydrostatic pressure, we discovered that the amplitude of the anomalous component significantly decreases at the transition to the H phase, which might correspond to the partial annihilation of nodal line structures.Comment: 29 page, 14 figure

    Relationships between a roller and a dynamic pressure distribution in circular hydraulic jumps

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    We investigated numerically the relation between a roller and the pressure distribution to clarify the dynamics of the roller in circular hydraulic jumps. We found that a roller which characterizes a type II jump is associated with two high pressure regions after the jump, while a type I jump (without the roller) is associated with only one high pressure region. Our numerical results show that building up an appropriate pressure field is essential for a roller.Comment: 10 pages, 7 PS files. To appear in PR

    187^{187}Re(\gamm,n) cross section close to and above the neutron threshold

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    The neutron capture cross section of the unstable nucleus 186^{186}Re is studied by investigating the inverse photodisintegration reaction 187^{187}Re(γ\gamma,n). The special interest of the {\it s}-process branching point 186^{186}Re is related to the question of possible {\it s}-process contributions to the abundance of the {\it r}-process chronometer nucleus ^{187}Re.Weusethephotoactivationtechniquetomeasurephotodisintegrationrates.Ourexperimentalresultsareingoodagreementwithtwodifferentstatisticalmodelcalculations.AlthoughthecrosssectionspredictedbybothmodelsfortheinversereactionRe. We use the photoactivation technique to measure photodisintegration rates. Our experimental results are in good agreement with two different statistical model calculations. Although the cross sections predicted by both models for the inverse reaction ^{186}Re(n,Re(n,\gamma)istoolowtoremovetheoverproductionof) is too low to remove the overproduction of ^{186}$Os; the two predicted neutron-capture cross sections differ by a factor of 2.4; this calls for future theoretical study.Comment: Phys. Rev. C, in pres

    Beta-decay rates for the s-process

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    Amelioration of normothermic canine liver ischemia with prostacyclin.

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    A model of hepatic ischemia was developed in dogs using a pump-driven splanchnic-to-jugular vein bypass during crossclamping of the portal triad. An LD50 was established with three hours of ischemia. PGI2 given for one hour before the ischemic insult ameliorated the ischemic injury and increased survival

    Note on Triangle Anomalies and Assignment of Singlet in 331-like Model

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    It is pointed out that in the 331331-like model which uses both fundamental and complex conjugate representations for an assignment of the representations to the left-handed quarks and the scalar representation to their corresponding right-handed counterparts, the nature of the scalar should be taken into account in order to make the fermion triangle anomalies in the theory anomaly-free, i.e. renormalizable in a sense with no anomalies, even after the spontaneous symmetry breaking.Comment: 8 page no figures, acknowledgments adde
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