32 research outputs found

    The Dirac form factor predicts the Pauli form factor in the Endpoint Model

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    We compute the momentum-transfer dependence of the proton Pauli form factor F2F_{2} in the endpoint overlap model. We find the model correctly reproduces the scaling of the ratio of F2F_{2} with the Dirac Form factor F1F_{1} observed at the Jefferson Laboratory. The calculation uses the leading-power, leading twist Dirac structure of the quark light-cone wave function, and the same endpoint dependence previously determined from the Dirac form factor F1F_{1}. There are no parameters and no adjustable functions in the endpoint model's prediction for F2F_{2}. The model's predicted ratio F2(Q2)/F1(Q2)F_{2}(Q^{2})/F_{1}(Q^{2}) is quite insensitive to the endpoint wave function, which explains why the observed ratio scales like 1/Q1/Q down to rather low momentum transfers. The endpoint model appears to be the only comprehensive model consistent with all form factor information as well as reproducing fixed-angle proton-proton scattering at large momentum transfer. Any one of the processes is capable of predicting the others.Comment: 12 pages, 3 figure

    Pressure dependent mechanical and thermodynamical properties of Hg

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    The mechanical, thermodynamical and elastic properties of Hg0.91Mn0.09Te compound are calculated by formulating an effective interionic interaction potential. This potential consists of the long-range Coulomb, three body force parameter, the Hafemeister and Flygare type short-range overlap repulsion extended upto the second neighbor ions and the van der Waals (vdW) interaction. The estimated values of phase transition pressure have revealed reasonably good agreement with the available experimental data on the phase transition pressure Pt = 11.5 GPa and the vast volume discontinuity in pressure-volume (PV) phase diagram indicate the structural phase transition from zincblende (B3) to rock salt (B1) structure. Later on, the Poisson's ratio ν, the ratio RS/B of S (Voigt averaged shear modulus) over B (bulk modulus), elastic anisotropy parameter, elastic wave velocity, average wave velocity and Debye temperature as functions of pressure is calculated. From Poisson's ratio and the ratio RS/B it is inferred that Hg0.91Mn0.09Te is brittle in nature in both B3 phase and B1 phase. To our knowledge this is the first quantitative theoretical prediction of the pressure dependence of ductile (brittle) nature of Hg0.91Mn0.09Te compounds and still awaits experimental confirmations
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