7,363 research outputs found

    Penguins and Mixing Dependent CP Violation

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    Constraints on angles of Unitarity triangle are reviewed, and in particular constraint on γ\gamma from limit on Δms\Delta m_s is emphasized. Effects of penguin diagram on measurement of β\beta and α\alpha are then reviewed. New measurements on B→π+π−B \to \pi^+\pi^- in QCD improved factorization approximation suggest large penguin effects. It is possible to estimate the error in measurement of α\alpha as a function of γ\gamma for different ∣Vub/Vcb∣|V_{ub} /V_{cb}| values.Comment: LaTeX, 11 pages, 3 eps figures, Talk presented at the Third International Conference on B Physics and CP Violation, Taipei, December 3-7, 199

    CP Violating Rate Difference Relations for B→PPB\to PP and B→PVB \to PV in Broken SU(3)

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    Within the standard model there exist certain relations between CP violating rate differences in B decays in the SU(3) limit. We study SU(3) breaking corrections to these relations in the case of charmless, hadronic, two body BB decays using the improved factorization model of Ref.\cite{3}. We consider the cases B→PPB \to PP and B→PVB \to PV for both BdB_d and BsB_s mesons. We present an estimate for ACP(π−π+)A_{CP}(\pi^- \pi^+) in terms of ACP(K−π+)A_{CP}(K^- \pi^+).Comment: Latex 13 pages, no figure

    Leptoquark explanation of HERA anomaly in the context of gauge unification

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    We examine the consequences of leptoquark explanation of HERA anomaly in the context of R parity conserving supersymmetric gauge unified theory with the gauge unification scale at ∼1016\sim 10^{16} GeV. We pointed out the difficulty of constructing a grandunified theory. However gauge unification is still possible at ∼1016\sim 10^{16} GeV when additional multiplets are introduced. We determine the mass spectrum of these additional fields (fermions and scalars) in gauge mediated and supergravity scenarios. Unique signatures and mass bounds are discussed.Comment: 19 pages(Latex), 1 PS Figur

    Overview of escalator applications in rail transit

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    The difference in operating environment and in construction between escalators in transit and nontransit use, the impact of recent escalator innovations, and areas which could benefit from urban mass transportation administration sponsored research and development are determined. Several factors causing a more severe transit escalator operating environment are identified. There are no significant design differences between transit and nontransit escalators. Recent innovations that have affected performance and cost include outdoor escalators, extra flat steps at both landings, and modular escalators. Data were collected by interviews at transit agencies. Long term, unscheduled, escalator maintenance records were available for analysis from one property. A description of escalator operating principles is provided. Transit represents less than 5% of the U.S. escalator market. Transit agencies have limited leverage on escalator industry practices. A substantial impact on transit escalator cost and performance can be achieved by research identifying when and how to apply and specify several of the more recent innovations. Purchase of escalators under long term (25 year) maintenance contracts is one method that has been used to promote escalators manufactured for minimum life cycle cost

    Consequences of R-Parity violating interactions for anomalies in Bˉ→D(∗)τνˉ\bar B\to D^{(*)} \tau \bar \nu and b→sμ+μ−b\to s \mu^+\mu^-

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    We investigate the possibility of explaining the enhancement in semileptonic decays of Bˉ→D(∗)τνˉ\bar B \to D^{(*)} \tau \bar \nu, the anomalies induced by b→sμ+μ−b\to s\mu^+\mu^- in Bˉ→(K,K∗,ϕ)μ+μ−\bar B\to (K, K^*, \phi)\mu^+\mu^- and violation of lepton universality in RK=Br(Bˉ→Kμ+μ−)/Br(Bˉ→Ke+e−)R_K = Br(\bar B\to K \mu^+\mu^-)/Br(\bar B\to K e^+e^-) within the framework of R-parity violating (RPV) MSSM. Exchange of down type right-handed squark coupled to quarks and leptons yield interactions which are similar to leptoquark induced interactions that have been proposed to explain the Bˉ→D(∗)τνˉ\bar B \to D^{(*)} \tau \bar \nu by tree level interactions and b→sμ+μ−b\to s \mu^+\mu^- anomalies by loop induced interactions, simultaneously. However, the Yukawa couplings in such theories have severe constraints from other rare processes in BB and DD decays. Although this interaction can provide a viable solution to R(D(∗))R(D^{(*)}) anomaly, we show that with the severe constraint from Bˉ→Kννˉ\bar B \to K \nu \bar \nu, it is impossible to solve the anomalies in b→sμ+μ−b\to s \mu^+\mu^- process simultaneously.Comment: RevTex, 13 pages, three figures. In our earlier version, we had neglected a contribution to C^{NP}_9 and obtained erroneous conclusions which we have corrected them in this versio

    Evaluation of ADAM/1 model for advanced coal extraction concepts

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    Several existing computer programs for estimating life cycle cost of mining systems were evaluated. A commercially available program, ADAM/1 was found to be satisfactory in relation to the needs of the advanced coal extraction project. Two test cases were run to confirm the ability of the program to handle nonconventional mining equipment and procedures. The results were satisfactory. The model, therefore, is recommended to the project team for evaluation of their conceptual designs

    Triple Neutral Gauge Boson Couplings in Noncommutative Standard Model

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    It has been shown recently that the triple neutral gauge boson couplings are not uniquely determined in noncommutative extension of the Standard Model (NCSM). Depending on specific schemes used, the couplings are different and may even be zero. To distinguish different realizations of the NCSM, additional information either from theoretical or experimental considerations is needed. In this paper we show that these couplings can be uniquely determined from considerations of unification of electroweak and strong interactions. Using SU(5) as the underlying theory and integrating out the heavy degrees of freedom, we obtain unique non-zero new triple γγγ\gamma\gamma\gamma, γγZ\gamma \gamma Z, γZZ\gamma ZZ, ZZZZZZ, γGG\gamma GG, ZGGZGG and GGGGGG couplings at the leading order in the NCSM. We also briefly discuss experimental implications.Comment: 8 pages, Latex, no figur

    M\"{o}ller and Bhabha scattering in the noncommutative standard model

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    We study the M\"{o}ller and Bhabha scattering in the noncommutative extension of the standard model(SM) using the Seiberg-Witten maps of this to first order of the noncommutative parameter θμν\theta_{\mu \nu}. We look at the angular distribution dσ/dΩd\sigma/d\Omega to explore the noncommutativity of space-time at around ΛNC∼\Lambda_{NC} \sim TeV and find that the distribution deviates significantly from the one obtained from the commutative version of the standard model.Comment: 15 pages, 14 eps figures.Text is modified a little and version to appear in Phys.Rev.
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