23,911 research outputs found

    Azimuthal distributions of radial momentum and velocity in relativistic heavy ion collisions

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    Azimuthal distributions of radial (transverse) momentum, mean radial momentum, and mean radial velocity of final state particles are suggested for relativistic heavy ion collisions. Using transport model AMPT with string melting, these distributions for Au + Au collisions at 200 GeV are presented and studied. It is demonstrated that the distribution of total radial momentum is more sensitive to the anisotropic expansion, as the anisotropies of final state particles and their associated transverse momentums are both counted in the measure. The mean radial velocity distribution is compared with the radial {\deg}ow velocity. The thermal motion contributes an isotropic constant to mean radial velocity

    A study of semi-inclusive charmless B→πXB \to \pi X decays

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    We study semi-inclusive charmless decays B→πXB \to \pi X in detail, such as Bˉ0→π±(0)X\bar B^0 \to \pi^{\pm (0)} X, B0→π±(0)XB^0 \to \pi^{\pm (0)} X, B±→π±(0)XB^{\pm} \to \pi^{\pm (0)} X, where XX does not contain a charm (anti)quark. We find that the process Bˉ0→π−X\bar B^0 \to \pi^- X (B0→π+XB^0 \to \pi^+ X) can be particularly useful for determination of the CKM matrix element ∣Vub∣|V_{ub}|. We calculate and present the branching ratio (BR) of Bˉ0→π−X\bar B^0 \to \pi^- X as a function of ∣Vub∣|V_{ub}|, with an estimate of possible uncertainties. It is expected that the BR is an order of 10−410^{-4}. Our estimation indicates that one can phenomenologically determine ∣Vub∣|V_{ub}| with reasonable accuracy by measuring the BR of Bˉ0→π−X\bar B^0 \to \pi^- X (B0→π+XB^0 \to \pi^+ X).Comment: 18 pages, 7 figures; Revtex; version accepted for publication in Eur. Phys. J.

    Persistent Current From the Competition Between Zeeman Coupling and Spin-Orbit Interaction

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    Applying the non-adiabatic Aharonov-Anandan phase approach to a mesoscopic ring with non-interacting many electrons in the presence of the spin-orbit interaction, Zeeman coupling and magnetic flux, we show that the time-reversal symmetry breaking due to Zeeman coupling is intrinsically different from that due to magnetic flux. We find that the direction of the persistent currents induced by the Zeeman coupling changes periodically with the particle number, while the magnetic flux determines the direction of the induced currents by its sign alone.Comment: 5 pages, ReVTeX, including 3 figures on request,Submitted to Phys.Rev.Let

    Electroweak phase transition in a nonminimal supersymmetric model

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    The Higgs potential of the minimal nonminimal supersymmetric standard model (MNMSSM) is investigated within the context of electroweak phase transition. We investigate the allowed parameter space yielding correct electroweak phase transitoin employing a high temperature approximation. We devote to phenomenological consequences for the Higgs sector of the MNMSSM for electron-positron colliders. It is observed that a future e+e−e^+ e^- linear collider with s=1000\sqrt{s} = 1000 GeV will be able to test the model with regard to electroweak baryogenesis.Comment: 28 pages, 5 tables, 12 figure
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