56 research outputs found

    Renormalization group evolution of the CKM matrix

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    We present here the most important ideas, equations and solutions for the running of all the quark Yukawa couplings and all the elements of the Cabibbo-Kobayashi-Maskawa matrix, in the approximation of one loop, and up to order λ4\lambda ^{4}, where λ0.22\lambda \sim 0.22 is the sine of the Cabibbo angle. Our purpose is to determine what the evolution of these parameters may indicate for the physics of the standard model (SM), the minimal supersymmetric standard model (MSSM) and for the Double Higgs Model (DHM).Comment: Talk given in the X Mexican School of Particles and Fields, Playa del Carmen, Mexico, 2002. 6 pages, LaTeX, needs aipproc.cls styl

    Quark mixings as a test of a new symmetry of quark Yukawa couplings

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    Based on the hierarchy exhibited by quarks masses at low energies, we assume that Yukawa couplings of up and down quarks are related by YuYd2Y_u\propto Y_d^2 at grand unification scales. This ansatz gives rise to a symmetrical CKM matrix at the grand unification (GU) scale. Using three specific models as illustrative examples for the evolution down to low energies, we obtain the entries and asymmetries of the CKM matrix which are in very good agreement with their measured values. This indicates that the small asymmetry of the CKM matrix at low energies may be the effect of the renormalization group evolution only.Comment: LaTeX file, 10 pages including 1 tabl

    Renormalization Group Equations for the CKM matrix

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    We derive the one loop renormalization group equations for the Cabibbo-Kobayashi-Maskawa matrix for the Standard Model, its two Higgs extension and the minimal supersymmetric extension in a novel way. The derived equations depend only on a subset of the model parameters of the renormalization group equations for the quark Yukawa couplings so the CKM matrix evolution cannot fully test the renormalization group evolution of the quark Yukawa couplings. From the derived equations we obtain the invariant of the renormalization group evolution for three models which is the angle α\alpha of the unitarity triangle. For the special case of the Standard Model and its extensions with v1v2v_{1}\approx v_{2} we demonstrate that also the shape of the unitarity triangle and the Buras-Wolfenstein parameters ρˉ=(11/2λ2)ρ\bar{\rho}=(1-{1/2}\lambda^{2})\rho and ηˉ=(11/2λ2)η\bar{\eta}=(1-{1/2}\lambda^{2})\eta are conserved. The invariance of the angles of the unitarity triangle means that it is not possible to find a model in which the CKM matrix might have a simple, special form at asymptotic energies.Comment: 9 page

    Energy dependence of the quark masses and mixings

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    The one loop Renormalization Group Equations for the Yukawa couplings of quarks are solved. From the solution we find the explicit energy dependence on t=lnE/μt=\ln E/\mu of the evolution of the {\em down} quark masses q=d,s,bq=d,s,b from the grand unification scale down to the top quark mass mtm_{t}. These results together with the earlier published evolution of the {\em up} quark masses completes the pattern of the evolution of the quark masses. We also find the energy dependence of the absolute values of the Cabibbo-Kobayashi-Maskawa (CKM) matrix Vij|V_{ij}|. The interesting property of the evolution of the CKM matrix and the ratios of the quark masses: mu,c/mtm_{u,c}/m_{t} and md,s/mbm_{d,s}/m_{b} is that they all depend on tt through only one function of energy h(t)h(t).Comment: Talk presented at the IX Mexican School on Particles and Fields, August 9-19, Metepec, Pue., Mexico. To be published in the AIP Conference Proceedings. 5 pages and 1 eps figure included in the tex

    On Weyl Quantization from geometric Quantization

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    A. Weinstein has conjectured a nice looking formula for a deformed product of functions on a hermitian symmetric space of non-compact type. We derive such a formula for symmetric symplectic spaces using ideas from geometric quantization and prequantization of symplectic groupoids. We compute the result explicitly for the natural 2-dimensional symplectic manifolds: the euclidean plane, the sphere and the hyperbolic plane. For the euclidean plane we obtain the well known Moyal-Weyl product. The other cases show that Weinstein's original idea should be interpreted with care. We conclude with comments on the status of our result.Comment: 11 pages. (v2: corrected a couple of typos
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