1,672 research outputs found

    The Rotating Mass Matrix, the Strong CP Problem and Higgs Decay

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    We investigate a recent solution to the strong CP problem, obtaining a theta-angle of order unity, and show that a smooth trajectory of the massive eigenvector of a rank-one rotating mass matrix is consistent with the experimental data for both fermion masses and mixing angles (except for the masses of the lightest quarks). Using this trajectory we study Higgs decay and find suppression of Γ(Hccˉ)\Gamma(H\to c\bar{c}) compared to the standard model predictions for a range of Higgs masses. We also give limits for flavour violating decays, including a relatively large branching ratio for the τμ+\tau^-\mu^+ mode.Comment: 15 pages, 6 figures; improvements to introduction and preliminarie

    On the Corner Elements of the CKM and PMNS Matrices

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    Recent experiments show that the top-right corner element (Ue3U_{e3}) of the PMNS, like that (VubV_{ub}) of the CKM, matrix is small but nonzero, and suggest further via unitarity that it is smaller than the bottom-left corner element (Uτ1U_{\tau 1}), again as in the CKM case (Vub<VtdV_{ub} < V_{td}). An attempt in explaining these facts would seem an excellent test for any model of the mixing phenomenon. Here, it is shown that if to the assumption of a universal rank-one mass matrix, long favoured by phenomenologists, one adds that this matrix rotates with scale, then it follows that (A) by inputting the mass ratios mc/mt,ms/mb,mμ/mτm_c/m_t, m_s/m_b, m_\mu/m_\tau, and m2/m3m_2/m_3, (i) the corner elements are small but nonzero, (ii) Vub<VtdV_{ub} < V_{td}, Ue3<Uτ1U_{e 3} < U_{\tau 1}, (iii) estimates result for the ratios Vub/VtdV_{ub}/V_{td} and Ue3/Uτ1U_{e 3}/U_{\tau 1}, and (B) by inputting further the experimental values of Vus,VtbV_{us}, V_{tb} and Ue2,Uμ3U_{e2},U_{\mu 3}, (iv) estimates result for the values of the corner elements themselves. All the inequalities and estimates obtained are consistent with present data to within expectation for the approximations made.Comment: 9 pages, 2 figures, updated with new experimental data and more detail

    N-String Vertices in String Field Theory

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    We give the general form of the vertex corresponding to the interaction of an arbitrary number of strings. The technique employed relies on the ``comma" representation of String Field Theory where string fields and interactions are represented as matrices and operations between them such as multiplication and trace. The general formulation presented here shows that the interaction vertex of N strings, for any arbitrary N, is given as a function of particular combinations of matrices corresponding to the change of representation between the full string and the half string degrees of freedom.Comment: 22 pages, A4-Latex (latex twice), FTUV IFI

    New Angle on the Strong CP and Chiral Symmetry Problems from a Rotating Mass Matrix

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    It is shown that when the mass matrix changes in orientation (rotates) in generation space for changing energy scale, then the masses of the lower generations are not given just by its eigenvalues. In particular, these masses need not be zero even when the eigenvalues are zero. In that case, the strong CP problem can be avoided by removing the unwanted θ\theta term by a chiral transformation in no contradiction with the nonvanishing quark masses experimentally observed. Similarly, a rotating mass matrix may shed new light on the problem of chiral symmetry breaking. That the fermion mass matrix may so rotate with scale has been suggested before as a possible explanation for up-down fermion mixing and fermion mass hierarchy, giving results in good agreement with experiment.Comment: 14 page

    Witten's cubic vertex in the comma theory (I)

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    It is shown that Witten's interaction 3-vertex is a solution to the comma overlap equations; hence establishing the equivalence between the conventional and the 'comma' formulation of interacting string theory at the level of vertices

    A Solution of the Strong CP Problem Transforming the theta-angle to the KM CP-violating Phase

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    It is shown that in the scheme with a rotating fermion mass matrix (i.e. one with a scale-dependent orientation in generation space) suggested earlier for explaining fermion mixing and mass hierarchy, the theta-angle term in the QCD action of topological origin can be eliminated by chiral transformations, while giving still nonzero masses to all quarks. Instead, the effects of such transformations get transmitted by the rotation to the CKM matrix as the KM phase giving, for θ\theta of order unity, a Jarlskog invariant typically of order 10510^{-5} as experimentally observed. Strong and weak CP violations appear then as just two facets of the same phenomenon.Comment: 14 pages, 2 figure

    Chiral corrections to the SU(2)×SU(2)SU(2)\times SU(2) Gell-Mann-Oakes-Renner relation

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    The next to leading order chiral corrections to the SU(2)×SU(2)SU(2)\times SU(2) Gell-Mann-Oakes-Renner (GMOR) relation are obtained using the pseudoscalar correlator to five-loop order in perturbative QCD, together with new finite energy sum rules (FESR) incorporating polynomial, Legendre type, integration kernels. The purpose of these kernels is to suppress hadronic contributions in the region where they are least known. This reduces considerably the systematic uncertainties arising from the lack of direct experimental information on the hadronic resonance spectral function. Three different methods are used to compute the FESR contour integral in the complex energy (squared) s-plane, i.e. Fixed Order Perturbation Theory, Contour Improved Perturbation Theory, and a fixed renormalization scale scheme. We obtain for the corrections to the GMOR relation, δπ\delta_\pi, the value δπ=(6.2,±1.6)\delta_\pi = (6.2, \pm 1.6)%. This result is substantially more accurate than previous determinations based on QCD sum rules; it is also more reliable as it is basically free of systematic uncertainties. It implies a light quark condensate 2GeV=(267±5MeV)3 \simeq \equiv |_{2\,\mathrm{GeV}} = (- 267 \pm 5 MeV)^3. As a byproduct, the chiral perturbation theory (unphysical) low energy constant H2rH^r_2 is predicted to be H2r(νχ=Mρ)=(5.1±1.8)×103H^r_2 (\nu_\chi = M_\rho) = - (5.1 \pm 1.8)\times 10^{-3}, or H2r(νχ=Mη)=(5.7±2.0)×103H^r_2 (\nu_\chi = M_\eta) = - (5.7 \pm 2.0)\times 10^{-3}.Comment: A comment about the value of the strong coupling has been added at the end of Section 4. No change in results or conslusion

    Bottom quark mass and QCD duality

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    The mass of the bottom quark is analyzed in the context of QCD finite energy sum rules. In contrast to the conventional approach, we use a large momentum expansion of the QCD correlator including terms to order alpha(S)(2)(m(b)(2)/q(2))(6) with the upsilon resonances from e(+)c(-) annihilation data as main input. A stable result m(b)(m(b)) = (4.19 +/- 0.05) GeV for the bottom quark mass is obtained. This result agrees with the independent calculations based on the inverse moment analysis

    Nucleation and Growth of the Zn-Fe Alloy from a Chloride Electrolyte

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    In this study, the kinetics of Zn-Fe codeposition was investigated in chloride acidic solution using cyclic voltammetry. Anomalous codeposition is detected and this mechanism depends on the Zn(II) / Fe(II) concentration ratio in the electrolytic bath. The study of early stages of electrodeposition showed that Zn- Fe follows a theoretical response to instantaneous nucleation evolves into a progressive nucleation according to the model of Scharifker and Hills. The morphology and structure of the coatings is discussed using characterization techniques. Dense, uniform, and singlephased Zn-Fe coatings could be obtained with a Zn-Fe ratio of 1/3. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3531
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