2,233 research outputs found

    Residual interaction effects on deeply bound pionic states in Sn and Pb isotopes

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    We have studied the residual interaction effects theoretically on the deeply bound pionic states in Pb and Sn isotopes. We need to evaluate the residual interaction effects carefully in order to deduce the nuclear medium effects for pion properties, which are believed to provide valuable information on nuclear chiral dynamics. The s- and p-wave π−N\pi-N interactions are used for the pion-nucleon residual interactions. We show that the complex energy shifts are around [(10-20)+i(2-7)]keV for 1s states in Sn, which should be taken into account in the analyses of the high precision data of deeply bound pionic 1s1s states in Sn isotopes.Comment: REVTEX4, 6 pages, 5 tables, Submitted to Phys. Rev. C, Some explanations are added in Version

    Effect of Maceration on \u3ci\u3ein Sacco\u3c/i\u3e Degradability and Energy Content of Low-Moisture Round Bale Alfalfa Silage

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    The aim of this study was to determine the effect of maceration on in sacco degradability and energy content of low-moisture alfalfa (Medicago sativa L.) silage. The results of two treatments were compared: 1) maceration, in which the alfalfa was processed through a large- scale forage mat maker prior to wilting to approximately 50% DM content (FM treatment), and 2) conventional conditioning, in which the alfalfa was tedded and wilted to the same DM content as that in the FM treatment (CC treatment). Silage bales were chopped in 20-mm pieces for each experiment. In sacco degradabilities of DM, CP and NDF of silage stems were estimated with two fistulated cows incubated for 3, 6, 12, 24, 48 and 72 h. DE and ME contents of FM- and CC-treated silage were measured using a respiration chamber with two dry cows. In sacco DM degradability was similar for both FM- and CC- treated silage, but CP degradability of FM-treated silage was higher than that of CC-treated silage. There were no differences between FM- and CC-treated silage in DE, ME and TDN contents. These results suggested that maceration increased the degradable fraction of CP in the alfalfa stem. However, in chopped silage, maceration has no effects on digestibility and metabolizability of energy

    Ice: a strongly correlated proton system

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    We discuss the problem of proton motion in Hydrogen bond materials with special focus on ice. We show that phenomenological models proposed in the past for the study of ice can be recast in terms of microscopic models in close relationship to the ones used to study the physics of Mott-Hubbard insulators. We discuss the physics of the paramagnetic phase of ice at 1/4 filling (neutral ice) and its mapping to a transverse field Ising model and also to a gauge theory in two and three dimensions. We show that H3O+ and HO- ions can be either in a confined or deconfined phase. We obtain the phase diagram of the problem as a function of temperature T and proton hopping energy t and find that there are two phases: an ordered insulating phase which results from an order-by-disorder mechanism induced by quantum fluctuations, and a disordered incoherent metallic phase (or plasma). We also discuss the problem of decoherence in the proton motion introduced by the lattice vibrations (phonons) and its effect on the phase diagram. Finally, we suggest that the transition from ice-Ih to ice-XI observed experimentally in doped ice is the confining-deconfining transition of our phase diagram.Comment: 12 pages, 9 figure

    Nuclear Quadrupole Effects in Deeply Bound Pionic Atoms

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    We have studied nuclear quadrupole deformation effects in deeply bound pionic atoms theoretically. We have evaluated the level shifts and widths of the hyperfine components using the first order perturbation theory and compared them with the effects of neutron skin. We conclude that the nuclear quadrupole deformation effects for deeply bound 1s1s and 2p2p states are very difficult to observe and that the effects could be observed for 3d3d states. We also conclude that the deformation effects are sensitive to the parameters of the pion-nucleus optical potential.Comment: Latex 11pages, Figures available on reques

    A Compact Gas Cerenkov Detector with Novel Optics

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    We discuss the design and performance of a threshold Cerenkov counter for identification of charged hadrons. The radiator is pressurized gas, which is contained in thin-walled cylindrical modules. A mirror system of novel design transports Cerenkov photons to photomultiplier tubes. This system is compact, contains relatively little material, and has a large fraction of active volume. A prototype of a module designed for the proposed CLEO III detector has been studied using cosmic rays. Results from these studies show good agreement with a detailed Monte Carlo simulation of the module and indicate that it should achieve separation of pions and kaons at the 2.5-3.0sigma level in the momentum range 0.8-2.8 GeV/c. We predict performance for specific physics analyses using a GEANT-based simulation package.Comment: Submitted to NIM. 23 pages, 11 postscript figures. Postscript file is also available at http://w4.lns.cornell.edu/public/CLNS/199
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