1,372 research outputs found

    CP Violation in D0 - anti-D0 Oscillations: General Considerations and Applications to the Littlest Higgs Model with T-Parity

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    The observed D0 - anti-D0 oscillations provide a new stage in our search for New Physics in heavy flavour dynamics. The theoretical verdict on the observed values of x_D and y_D remains ambiguous: while they could be totally generated by Standard Model dynamics, they could also contain a sizable or even leading contribution from New Physics. Those oscillations are likely to enhance the observability of CP violation as clear manifestations of New Physics. We present general formulae for D0 - anti-D0 oscillations, concentrating on the case of negligible direct CP violation. In particular we derive a general formula for the time-dependent mixing-induced CP asymmetry in decays to a CP eigenstate and its correlation with the semileptonic CP asymmetry a_SL(D0) in D0(t) -> l nu K. We apply our formalism to the Littlest Higgs model with T-parity, using the time-dependent CP asymmetry in D -> K_S phi as an example. We find observable effects at a level well beyond anything possible with CKM dynamics. Comparisons with CP violation in the K and B systems offer an excellent test of this scenario and reveal the specific pattern of flavour and CP violation in the D0 - anti-D0 system predicted by this model. We discuss a number of charm decays that could potentially offer an insight in the dynamics of CP violation in D decays. We also apply our formalism to B_s - anti-B_s mixing.Comment: 26 pages, 9 png figures, 1 table. v2: eq. (A.1) corrected, minor clarifying comments and few references added. v3: typos corrected, matches published versio

    The Enchantress : Waltzes

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    https://digitalcommons.library.umaine.edu/mmb-ps/2742/thumbnail.jp

    Under The Rose : Waltzes

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    https://digitalcommons.library.umaine.edu/mmb-ps/2822/thumbnail.jp

    Top quark chromomagnetic dipole moment in the littlest Higgs model with T-parity

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    The littlest Higgs model with T-parity, which is called LHTLHT model, predicts the existence of the new particles, such as heavy top quark, heavy gauge bosons, and mirror fermions. We calculate the one-loop contributions of these new particles to the top quark chromomagnetic dipole moment (CMDM)(CMDM) ΔK\Delta K. We find that the contribution of the LHTLHT model is one order of magnitude smaller than the standard model prediction value.Comment: latex files, 12 pages, 3 figure

    Brief review of the searches for the rare decays Bs0μ+μB^0_s \rightarrow \mu^+ \mu^- and B0μ+μB^0 \rightarrow \mu^+ \mu^-

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    The current experimental status of the searches for the very rare decays Bs0μ+μB^0_s \rightarrow \mu^+ \mu^- and B0μ+μB^0 \rightarrow \mu^+ \mu^- is discussed. These channels are highly sensitive to various extensions of the Standard Model, specially in the scalar and pseudoscalar sector. The recent, most sensitive measurements from the CDF, ATLAS, CMS and LHCb collaborations are discussed and the combined upper exclusion limit on the branching fractions determined by the LHC experiments is shown to be 4.2×1094.2\times 10^{-9} for Bs0μ+μB^0_s \rightarrow \mu^+ \mu^- and 0.8×1090.8\times 10^{-9} for B0μ+μB^0 \rightarrow \mu^+ \mu^-. The implications of these tight bounds on a selected set of New Physics models is sketched.Comment: 20 pages, 15 figures, invited review for Modern Physics Letters

    Minimal Flavour Violation and Beyond

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    Starting from the effective-theory framework for Minimal Flavour Violation, we give a systematic definition of next-to-minimal (quark) flavour violation in terms of a set of spurion fields exhibiting a particular hierarchy with respect to a small (Wolfenstein-like) parameter. A few illustrative examples and their consequences for charged and neutral decays with different quark chiralities are worked out in some detail. Our framework can be used as a model-independent classification scheme for the parameterization of flavour structure from physics beyond the Standard Model.Comment: 17 pages, no figures, phenomenological discussion extended, references adde

    Stingy Moon

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    https://digitalcommons.library.umaine.edu/mmb-vp/6350/thumbnail.jp

    Colleen : An Irish Love Song

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    https://digitalcommons.library.umaine.edu/mmb-vp/3482/thumbnail.jp

    Precise limits from lepton flavour violating processes on the Littlest Higgs model with T-parity

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    We recalculate the leading one-loop contributions to mu > e gamma and mu -> eee in the Littlest Higgs model with T-parity, recovering previous results for the former. When all the Goldstone interactions are taken into account, the latter is also ultraviolet finite. The present experimental limits on these processes require a somewhat heavy effective scale ~2.5 TeV, or the flavour alignment of the Yukawa couplings of light and heavy leptons at the ~10% level, or the splitting of heavy lepton masses to a similar precision. Present limits on tau decays set no bounds on the corresponding parameters involving the tau leptonComment: 41 pages, 11 figures; v3: matches published version in JHE

    Photon-induced production of the mirror quarks from the LHTLHT model at the LHCLHC

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    The photon-induced processes at the LHCLHC provide clean experimental conditions due to absence of the proton remnants, which might produce complementary and interesting results for tests of the standard model and for searching of new physics. In the context of the littlest HiggsHiggs model with T-parity, we consider the photon-induced production of the mirror quarks at the LHCLHC. The cross sections for various production channels are calculated and a simply phenomenology analysis is performed by assuming leptonic decays.Comment: 20 pages, 10 figure
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