857 research outputs found

    CP violation in 5D Split Fermions Scenario

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    We give a new configuration of split fermion positions in one extra dimension with two different Yukawa coupling strengths for up-type, huh_u, and down-type, hdh_d, quarks at huhd=36.0\frac{h_u}{h_d}=36.0. The new configurations can give enough CP violating (CPV) phase for accommodating all currently observed CPV processes. Therefore, a 5D standard model with split fermions is viable. In addition to the standard CKM phase, new CPV sources involving Kaluza-Klein(KK) gauge bosons coupling which arise from the fact that unitary rotation which transforms weak eigenstates into their mass eigenstates only holds for the zero modes which are the SM fields and not for the KK excitations. We have examined the physics of kaon, neutron, and B/DB/D mesons and found the most stringent bound on the size RR of the extra dimension comes from ϵK|\epsilon_K|. Moreover, it depends sensitively on the width, σ\sigma, of the Gaussian wavefunction in the extra dimension used to describe of the fermions. When σ/R1\sigma/R \ll 1, the constraint will be lifted due to GIM suppression on the flavor changing neutral current(FCNC) and CPV couplings.Comment: 24 pages, 8 figure

    Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419

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    Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome se-quence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a fea-ture unique to this medic microsymbiont

    Flexible active compensation based on load conformity factors applied to non-sinusoidal and asymmetrical voltage conditions

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    This study proposes a flexible active power filter (APF) controller operating selectively to satisfy a set of desired load performance indices defined at the source side. The definition of such indices, and of the corresponding current references, is based on the orthogonal instantaneous current decomposition and conformity factors provided by the conservative power theory. This flexible approach can be applied to single- or three-phase APFs or other grid-tied converters, as those interfacing distributed generators in smart grids. The current controller is based on a modified hybrid P-type iterative learning controller which has shown good steady-state and dynamic performances. To validate the proposed approach, a three-phase four-wire APF connected to a non-linear and unbalanced load has been considered. Experimental results have been generated under ideal and non-ideal voltage sources, showing the effectiveness of the proposed flexible compensation scheme, even for weak grid scenarios

    Radiative Corrections to Fixed Target Moller Scattering Including Hard Bremsstrahlung Effects

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    We present a calculation of the complete O(α)O(\alpha) electroweak radiative corrections to the Moller scattering process e^-e^- -> e^-e^-, including hard bremsstrahlung contributions. We study the effects of these corrections on both the total cross section and polarization asymmetry measured in low energy fixed target experiments. Numerical results are presented for the experimental cuts relevant for E-158, a fixed target e^-e^- experiment being performed at SLAC; the effect of hard bremsstrahlung is to shift the measured polarization asymmetry by approximately +4%. We briefly discuss the remaining theoretical uncertainty in the prediction for the low energy Moller scattering polarization asymmetry.Comment: 22 pgs; minor clarifications added and typos fixe

    Thermodynamics of doubly charged CGHS model and D1-D5-KK black holes of IIB supergravity

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    We study the doubly charged Callan-Giddings-Harvey-Strominger (CGHS) model, which has black hole solutions that were found to be U-dual to the D1-D5-KK black holes of the IIB supergravity. We derive the action of the model via a spontaneous compactification on S^3 of the IIB supergravity on S^1*T^4 and obtain the general static solutions including black holes corresponding to certain non-asymptotically flat black holes in the IIB supergravity. Thermodynamics of them is established by computing the entropy, temperature, chemical potentials, and mass in the two-dimensional setup, and the first law of thermodynamics is explicitly verified. The entropy is in precise agreement with that of the D1-D5-KK black holes, and the mass turns out to be consistent with the infinite Lorentz boost along the M theory circle that is a part of the aforementioned U-dual chain.Comment: 21 pages, Revte

    Granular discharge and clogging for tilted hoppers

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    We measure the flux of spherical glass beads through a hole as a systematic function of both tilt angle and hole diameter, for two different size beads. The discharge increases with hole diameter in accord with the Beverloo relation for both horizontal and vertical holes, but in the latter case with a larger small-hole cutoff. For large holes the flux decreases linearly in cosine of the tilt angle, vanishing smoothly somewhat below the angle of repose. For small holes it vanishes abruptly at a smaller angle. The conditions for zero flux are discussed in the context of a {\it clogging phase diagram} of flow state vs tilt angle and ratio of hole to grain size

    Electric field and exciton structure in CdSe nanocrystals

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    Quantum Stark effect in semiconductor nanocrystals is theoretically investigated, using the effective mass formalism within a 4×44\times 4 Baldereschi-Lipari Hamiltonian model for the hole states. General expressions are reported for the hole eigenfunctions at zero electric field. Electron and hole single particle energies as functions of the electric field (EQD\mathbf{E}_{QD}) are reported. Stark shift and binding energy of the excitonic levels are obtained by full diagonalization of the correlated electron-hole Hamiltonian in presence of the external field. Particularly, the structure of the lower excitonic states and their symmetry properties in CdSe nanocrystals are studied. It is found that the dependence of the exciton binding energy upon the applied field is strongly reduced for small quantum dot radius. Optical selection rules for absorption and luminescence are obtained. The electric-field induced quenching of the optical spectra as a function of EQD\mathbf{E}_{QD} is studied in terms of the exciton dipole matrix element. It is predicted that photoluminescence spectra present anomalous field dependence of the emission lines. These results agree in magnitude with experimental observation and with the main features of photoluminescence experiments in nanostructures.Comment: 9 pages, 7 figures, 1 tabl

    Lepton Dipole Moments and Rare Decays in the CP-violating MSSM with Nonuniversal Soft-Supersymmetry Breaking

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    We investigate the muon anomalous magnetic dipole moment (MDM), the muon electric dipole moment (EDM) and the lepton-flavour-violating decays of the τ\tau-lepton, τμγ\tau \to \mu \gamma and τ3μ\tau\to 3\mu, in the CP-violating Minimal Supersymmetric Standard Model (MSSM) with nonuniversal soft-supersymmetry breaking. We evaluate numerically the muon EDM and the branching ratios B(τμγ)B(\tau \to \mu\gamma) and B(τ3μ)B(\tau \to 3\mu), after taking into account the experimental constraints from the electron EDM and muon MDM. Upon imposition of the experimental limits on our theoretical predictions for the aforementioned branching ratios and the muon MDM, we obtain an upper bound of about 1023ecm10^{-23} e\cdot cm on the muon EDM which lies well within the explorable reach of the proposed experiment at BNL.Comment: Latex, 26 pages, 8 figures, accepted for publication in Phys. Rev.

    Mass matrix Ansatz and lepton flavor violation in the THDM-III

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    Predictive Higgs-fermion couplings can be obtained when a specific texture for the fermion mass matrices is included in the general two-Higgs doublet model. We derive the form of these couplings in the charged lepton sector using a Hermitian mass matrix Ansatz with four-texture zeros. The presence of unconstrained phases in the vertices phi-li-lj modifies the pattern of flavor-violating Higgs interactions. Bounds on the model parameters are obtained from present limits on rare lepton flavor violating processes, which could be extended further by the search for the decay tau -> mu mu mu and mu-e conversion at future experiments. The signal from Higgs boson decays phi -> tau mu could be searched at the large hadron collider (LHC), while e-mu transitions could produce a detectable signal at a future e mu-collider, through the reaction e mu -> h0 -> tau tau.Comment: 17 pages, 9 figure

    De Sitter and Schwarzschild-De Sitter According to Schwarzschild and De Sitter

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    When de Sitter first introduced his celebrated spacetime, he claimed, following Schwarzschild, that its spatial sections have the topology of the real projective space RP^3 (that is, the topology of the group manifold SO(3)) rather than, as is almost universally assumed today, that of the sphere S^3. (In modern language, Schwarzschild was disturbed by the non-local correlations enforced by S^3 geometry.) Thus, what we today call "de Sitter space" would not have been accepted as such by de Sitter. There is no real basis within classical cosmology for preferring S^3 to RP^3, but the general feeling appears to be that the distinction is in any case of little importance. We wish to argue that, in the light of current concerns about the nature of de Sitter space, this is a mistake. In particular, we argue that the difference between "dS(S^3)" and "dS(RP^3)" may be very important in attacking the problem of understanding horizon entropies. In the approach to de Sitter entropy via Schwarzschild-de Sitter spacetime, we find that the apparently trivial difference between RP^3 and S^3 actually leads to very different perspectives on this major question of quantum cosmology.Comment: 26 pages, 8 figures, typos fixed, references added, equation numbers finally fixed, JHEP versio
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