5,876 research outputs found

    Electroweak Model Independent Tests for SU(3) Symmetry in Hadronic B Decays

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    We study effects of new physics beyond the Standard Model on SU(3) symmetry in charmless hadronic two body B decays. It is found that several equalities for some of the decay amplitudes, such as A(Bd(Bu)π+π,π+K(πKˉ0))=A(BsK+π,KK+(K0Kˉ0))A(B_d (B_u) \to \pi^+\pi^-,\pi^+ K^- (\pi^- \bar K^0)) =A(B_s \to K^+ \pi^-, K^- K^+ (K^0 \bar K^0)), A(Bdπ+ρ,πρ+,Kρ+,π+K)=A(BsK+ρ,πK+,KK+,K+K)A(B_d \to \pi^+\rho^-, \pi^- \rho^+, K^-\rho^+, \pi^+ K^{*-}) = A(B_s \to K^+ \rho^-, \pi^- K^{*+}, K^- K^{*+}, K^+ K^{*-}), A(Bd(Bu)ρ+ρ,ρ+K(ρKˉ0))=A(BsK+ρ,KK+(K0Kˉ0))A(B_d (B_u) \to \rho^+\rho^-, \rho^+ K^{*-}(\rho^- \bar K^{*0})) =A(B_s \to K^{*+} \rho^-, K^{*-} K^{*+} (K^{*0} \bar K^{*0})), predicted by SU(3) symmetry in the SM are not affected by new physics. These relations provide important electroweak model independent tests for SU(3) symmetry in B decays.Comment: 4 pages, revte

    Determining the Weak Phase γ\gamma From Charged BB Decays

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    A quadrangle relation is shown to be satisfied by the amplitudes for B+π0K+, π+K0, ηK+B^+ \to \pi^0 K^+,~\pi^+ K^0,~\eta K^+, and ηK+\eta' K^+. By comparison with the corresponding relation satisfied by BB^- decay amplitudes, it is shown that the relative phases of all the amplitudes can be determined up to discrete ambiguities. Making use of an SU(3) relation between amplitudes contributing to the above decays and those contributing to B±π±π0B^{\pm} \to \pi^{\pm} \pi^0, it is then shown that one can determine the weak phase γArg(VubVcb/VusVcs)\gamma \equiv {\rm Arg} (V_{ub}^* V_{cb}/V_{us}^* V_{cs}), where VV is the Cabibbo-Kobayashi-Maskawa matrix describing the charge-changing weak interactions between the quarks (u,c,t)(u,c,t) and (d,s,b)(d,s,b).Comment: 16 pages, latex, 7 uuencoded figure

    The CP violating phase γ\gamma from global fit of rare charmless hadronic B decays

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    We study constraints on the CP violating phase γ\gamma in the Kobayashi-Maskawa model using available experimental data. We first follow the conventional method to up date the constraint on γ\gamma by performing a χ2\chi^2 analysis using data from ϵK|\epsilon_K|, ΔmBd,s\Delta m_{B_{d,s}} and Vub/Vcb|V_{ub}/V_{cb}|. We also include the recent information on sin2β\sin2\beta in the analysis. We obtain the best fit for γ\gamma to be 6666^\circ and the 95% C.L. allowed range to be 428742^\circ \sim 87^\circ. We then develop a method to carry out a χ2\chi^2 analysis based on SU(3) symmetry using data from BππB\to \pi \pi and BKπB\to K \pi. We also discuss SU(3) breaking effects from model estimate. We find that present data on Bππ,KπB\to \pi\pi, K \pi can also give some constraint on γ\gamma although weaker than the earlier method limited by the present experimental errors. Future improved data will provide more stringent constraint. Finally we perform a combined fit using data from ϵK|\epsilon_K|, ΔmBd,s\Delta m_{B_{d,s}}, Vub/Vcb|V_{ub}/V_{cb}|, sin2β\sin2\beta and rare charmless hadronic B decays. The combined analysis gives γ=67\gamma=67^\circ for the best fit value and 438743^\circ \sim 87^\circ as the 95% C.L. allowed range. Several comments on other methods to determine γ\gamma based on SU(3) symmetry are also provided.Comment: Revised verion with the new experimental data from Belle and Babar included in the analysis to obtain the global fit for the CP violating phase gamma. RevTex, 32 pages and 8 figure

    A Novel Constraint Narrowing Technique for MIMO Unstable System

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    Frequency response data collection can be a boon for modeling of MIMO uncertain plant. System stability can be assessed either by transfer function or by state-space method. Both will arrive at matrix transformation and further decision approach. Both can be considered for diagonalization of matrix. It is a proven fact that when the matrix is diagonalized the elements of the principle diagonal are the Eigen values and these Eigen values are closed loop poles from which stability can be assessed. The feature of such a diagonal matrix is that its principle diagonal elements contain gains of all the feedback paths. Singular value decomposition is used here for diagonalization. Singular value decomposition technique has been demonstrated by many authors but, application of PCA with Euclidian norm has not been paid attention so far. The systems numerical array is fed to a digital processing tool such as Mat lab and SVD-PCA (Singular Value Decomposition- Principal Component Analysis) is applied to determine the reduction of disturbance or noise and to provide minimum sensitivity and error correction. There are Hull, Box and KB consistency narrowing techniques used previously and the idea is extended further and an SVD-PCA-Norm technique which is now referred as LA criteria has been demonstrated here

    Determination of CKM phases through rigid polygons of flavor SU(3) amplitudes

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    Some new methods for the extraction of CKM phases α\alpha and γ\gamma using flavor SU(3) symmetry have been suggested through the construction of rigid polygons in the complex plane with sides equal to the decay amplitudes of B mesons into two mesons belonging to the light (charmless) pseudoscalar octet. These rigid polygons incorporate all the possible amplitude triangles and, being overdetermined, also serve as consistency checks and in estimating the rates of some decay modes. The same techniques also lead to numerous useful amplitude triangles when octet-singlet mixing has been taken into account and nearly physical η,η\eta,\eta' are used.Comment: A few detailed explanations added, some rearrangement of sections and a few minor changes in notation. 19 pages, 1 PostScript figure, uses psfig.st

    Prospects for Direct CP Violaton in Exclusive and Inclusive Charmless B decays

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    Within the Standard Model, CP rate asymmetries for BKπ+,0B\to K^-\pi^{+,0} could reach 10%. With strong final state phases, they could go up to 20--30%, even for Kˉ0π\bar K^0\pi^- mode which would have opposite sign. We can account for Kπ+K^-\pi^{+}, Kˉ0π\bar K^0\pi^- and ϕK\phi K rate data with new physics enhanced color dipole coupling and destructive interference. Asymmetries could reach 40--60% for KπK\pi and ϕK\phi K modes and are all of the same sign. We are unable to account for Kπ0K^-\pi^0 rate. Our inclusive study supports our exclusive results.Comment: Minor changes, correct a small bug in Fig. 1(b). Version to appear in Phys. Rev. Let

    A Survey of the Galactic Plane for 6.7-GHz Methanol Masers I: l = 325.0 - 335.0 ; b = -0.53 - 0.53

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    We report the results of the first complete survey of an area of the Galactic Plane for maser emission from the 6.7-GHz transition of methanol. The survey covers a 10.6-square-degree region of the Galactic Plane in the longitude range 325-335 degrees and latitude range -0.53-0.53 degrees. The survey is sensitive to masers with a peak flux density greater than approximately 2.6 Jy. The weakest maser detected has a peak flux density of 2.3 Jy and the strongest a peak flux density of 425 Jy. We detected a total of 50 distinct masers, 26 of which are new detections. We show that many 6.7-GHz methanol masers are not associated with IRAS sources, and that some are associated with sources that have colours differing from those of a typical ultra-compact HII region (UCHII). We estimate that the number of UCHII regions in the Galaxy is significantly more than suggested by IRAS-based estimates, possibly by more than a factor of two.Comment: 19 pages including 4 figures, using LaTeX formatted with mn.sty, accepted for publication in MNRA

    CP Violation in a Multi-Higgs Doublet Model

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    We study CP violation in a multi-Higgs doublet model based on a S3×Z3S_3 \times Z_3 horizontal symmetry. We consider two mechanisms for CP violation in this model: a) CP violation due to complex Yukawa couplings; and b) CP violation due to scalar-pseudoscalar mixings. We find that the predictions for ϵ/ϵ\epsilon'/\epsilon, CP violation in B decays and the electric dipole moments of neutron and electron are different between these two mechanisms. These predictions are also dramatically different from the minimal Standard Model predictions.Comment: 17 pages + one figure, Revtex. Talk presented by Deshpande at the Conference WHEPP-3, December 199

    Model-independent analysis of \bbox{B}-\bbox{\bar B} mixing and \bbox{CP} violation in \bbox{B} decays

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    We present a framework to analyze effects of new physics beyond the standard model on BB-Bˉ\bar B mixing and CPCP violation in BB decays in a model-independent manner. Assuming that tree level decay amplitudes are dominated by the standard model ones, new physics contribution to the BB-Bˉ\bar B mixing can be extracted from several measurements at BB factories. Using this framework, we show the present constraint on new physics contribution to the BB-Bˉ\bar B mixing, and illustrate constraints expected to be given by future experiments at BB factories. We also point out a possibility that CPCP asymmetries in BψKSB\rightarrow\psi K_S, BππB\rightarrow\pi\pi, and BDKB\rightarrow DK modes look consistent with the standard model, even if a large new physics contribution is present in the BB-Bˉ\bar B mixing.Comment: 11 pages, 3 Postscript figures, also available via anonymous ftp at ftp://ftp.kek.jp/kek/preprints/TH/TH-44
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