16,740 research outputs found

    Quantum molecular dynamics simulations of the thermophysical properties of shocked liquid ammonia for pressures up to 1.3 TPa

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    We investigate via quantum molecular-dynamics simulations the thermophysical properties of shocked liquid ammonia up to the pressure 1.3 TPa and temperature 120000 K. The principal Hugoniot is predicted from wide-range equation of state, which agrees well with available experimental measurements up to 64 GPa. Our systematic study of the structural properties demonstrates that liquid ammonia undergoes a gradual phase transition along the Hugoniot. At about 4800 K, the system transforms into a metallic, complex mixture state consisting of NH3\textnormal{N}\textnormal{H}_{3}, N2\textnormal{N}_{2}, H2\textnormal{H}_{2}, N, and H. Furthermore, we discuss the implications for the interiors of Uranus and Neptune.Comment: 16 pages, 8 figures. arXiv admin note: text overlap with arXiv:1012.488

    B(s)β†’SB_{(s)}\to S transitions in the light cone sum rules with the chiral current

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    B(s)B_{(s)} semi-leptonic decays to the light scalar meson, B(s)β†’SlΞ½Λ‰l,Sllˉ  (l=e,ΞΌ,Ο„)B_{(s)}\to S l\bar{\nu}_l, S l \bar{l}\,\,(l=e,\mu,\tau), are investigated in the QCD light-cone sum rules (LCSR) with chiral current correlator. Having little knowledge of ingredients of the scalar mesons, we confine ourself to the two quark picture for them and work with the two possible Scenarios. The resulting sum rules for the form factors receive no contributions from the twist-3 distribution amplitudes (DA's), in comparison with the calculation of the conventional LCSR approach where the twist-3 parts play usually an important role. We specify the range of the squared momentum transfer q2q^2, in which the operator product expansion (OPE) for the correlators remains valid approximately. It is found that the form factors satisfy a relation consistent with the prediction of soft collinear effective theory (SCET). In the effective range we investigate behaviors of the form factors and differential decay widthes and compare our calculations with the observations from other approaches. The present findings can be beneficial to experimentally identify physical properties of the scalar mesons.Comment: 22 pages,16 figure
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