3,603 research outputs found

    Anomalously interacting extra neutral bosons

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    We study phenomenological consequences of the Standard Model extension by the new spin-1 chiral fields with the internal quantum numbers of the electroweak Higgs doublets. There are at least three different classes of theories, all motivated by the hierarchy problem, which predict new vector weak-doublets with masses not far from the electro-weak scale. We discuss resonance production of these neutral chiral Z* bosons at hadron colliders. The bosons can be observed as a Breit-Wigner resonance peak in the invariant dilepton mass distributions in the same way as the well-known extra gauge Z' bosons. This includes them into a list of very interesting objects for early searches with the first LHC data. Moreover, the Z* bosons have unique signatures in transverse momentum, angular and pseudorapidity distributions of the final leptons, which allow to distinguish them from the other heavy neutral resonances.Comment: 8 pages, 9 figures, uses cimento.cls: for Proceedings of the 2010 Rencontres de Physique de la Vallee d'Aoste, La Thuil

    Vibron transport in macromolecular chains

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    We study the hopping mechanism of the vibron excitation transport in the simple 1D model of biological macromolecular chains. We supposed that the vibron interaction with thermal oscillations of the macromolecular structural elements will result in vibron self -trapping, and the formation of the partial dressed vibron state. With use of the modified Holstein polaron model, we calculate vibron diffusivity in dependence of the basic system parameters and temperature. We obtain that the vibron diffusivity smoothly decreases in non adiabatic limit when the strength of the vibron-phonon coupling grows. However this dependence becomes by discontinuous one in case of growth of the adiabaticity of the system. The value of the critical point depends of the system temperature, and at room temperatures it belongs to the low or intermediate coupling regime. We discuss an application of these results to study of vibron transport to 3D bundles of such macromolecules chains considering it as polymer nanorods and to 2D polymer films organized from such macromolecules.Comment: 4 pages, 6 figures, contribution to the Proceedings of the Conference "Physical mesomechanics of multi-level systems`2014", September 3-5 2014, Tomsk, Russi

    Charged-Lepton-Flavour Violation in Kaon Decays in Supersymmetric Theories

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    We discuss rare kaon decays that violate charged-lepton flavour conservation in supersymmetric theories with and without R parity, in view of possible experiments using an intense proton source as envisaged for a neutrino factory. In the Minimal Supersymmetric Standard Model, such decays are generated by box diagrams involving charginos and neutralinos, but the limits from \mu -> e \gamma, \mu-e conversion and \Delta m_K constrain the branching ratios to challengingly small values. However, this is no longer the case in R-violating theories, where such decays may occur at tree level at rates close to the present experimental limits. Within this framework, we obtain bounds on products of LL\bar{E} and LQ\bar{D} operators from the experimental upper limits on K^0 -> \mu^\pm e^\mp and K^{\pm,0} -> \pi^{\pm,0} \mu^\pm e^\mp decays. We also note the possibility of like-sign lepton decays K^\pm -> \pi^\mp \ell^\pm \ell^\pm in the presence of non-zero \tilde{b}_L-\tilde{b}_R mixing. We conclude that rare kaon decays violating charged-lepton flavour conservation could be an interesting signature of R violation.Comment: 25 pages, 6 figures, Prepared for the Kaon Physics Working Group as part of the ECFA/CERN study of Neutrino Factory & Muon Storage Rings At CERN. Referencies added, constraints update
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