29,410 research outputs found

    Construction of some families of 2-dimensional crystalline representations

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    We construct explicitly some analytic families of etale (phi,Gamma)-modules, which give rise to analytic families of 2-dimensional crystalline representations. As an application of our constructions, we verify some conjectures of Breuil on the reduction modulo p of those representations, and extend some results (of Deligne, Edixhoven, Fontaine and Serre) on the representations arising from modular forms.Comment: 13 pages, english and french abstract

    Generalized Koszul properties for augmented algebras

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    Under certain conditions, a filtration on an augmented algebra A admits a related filtration on the Yoneda algebra E(A) := Ext_A(K, K). We show that there exists a bigraded algebra monomorphism from gr E(A) to E_Gr(gr A), where E_Gr(gr A) is the graded Yoneda algebra of gr A. This monomorphism can be applied in the case where A is connected graded to determine that A has the K_2 property recently introduced by Cassidy and Shelton.Comment: 14 page

    Up Sector of Minimal Flavor Violation: Top Quark Properties and Direct D meson CP violation

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    Minimal Flavor Violation in the up-type quark sector leads to particularly interesting phenomenology due to the interplay of flavor physics in the charm sector and collider physics from flavor changing processes in the top sector. We study the most general operators that can affect top quark properties and DD meson decays in this scenario, concentrating on two CP violating operators for detailed studies. The consequences of these effective operators on charm and top flavor changing processes are generically small, but can be enhanced if there exists a light flavor mediator that is a Standard Model gauge singlet scalar and transforms under the flavor symmetry group. This flavor mediator can satisfy the current experimental bounds with a mass as low as tens of GeV and explain observed DD-meson direct CP violation. Additionally, the model predicts a non-trivial branching fraction for a top quark decay that would mimic a dijet resonance.Comment: 27 pages, 7 figure

    Top Quark Forward-Backward Asymmetry and Same-Sign Top Quark Pairs

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    The top quark forward-backward asymmetry measured at the Tevatron collider shows a large deviation from standard model expectations. Among possible interpretations, a non-universal Z′Z^\prime model is of particular interest as it naturally predicts a top quark in the forward region of large rapidity. To reproduce the size of the asymmetry, the couplings of the Z′Z^\prime to standard model quarks must be large, inevitably leading to copious production of same-sign top quark pairs at the energies of the Large Hadron Collider (LHC). We explore the discovery potential for tttt and ttjttj production in early LHC experiments at 7-8 TeV and conclude that if {\it no} tttt signal is observed with 1 fb−1^{-1} of integrated luminosity, then a non-universal Z′Z^\prime alone cannot explain the Tevatron forward-backward asymmetry.Comment: Tevatron limit from same-sign tt search adde

    Relaxing-Precessional Magnetization Switching

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    A new way of magnetization switching employing both the spin-transfer torque and the torque by a magnetic field is proposed. The solution of the Landau-Lifshitz-Gilbert equation shows that the dynamics of the magnetization in the initial stage of the switching is similar to that in the precessional switching, while that in the final stage is rather similar to the relaxing switching. We call the present method the relaxing-precessional switching. It offers a faster and lower-power-consuming way of switching than the relaxing switching and a more controllable way than the precessional switching

    Higher Twist Effects in the Drell-Yan Angular Distribution

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    We study the Drell-Yan process πN→μ+μ−X\pi N \rightarrow \mu^+ \mu^- X at large xFx_F using perturbative QCD. A higher-twist mechanism suggested by Berger and Brodsky is known to qualitatively explain the observed xFx_F dependence of the muon angular distribution, but the predicted large xFx_F behavior differs quantitatively from observations. We have repeated the model calculation taking into account the effects of nonasymptotic kinematics. At fixed-target energies we find important corrections which improve the agreement with data. The asymptotic result of Berger and Brodsky is recovered only at much higher energies. We discuss the generic reasons for the large corrections at high xFx_F. A proper understanding of the xF→1x_F \to 1 data would give important information on the pion distribution amplitude and exclusive form factor.Comment: 8 pages in Latex with 3 figures appended as Postscript files, HU-TFT-94-12, LBL-35430. (The introductory part has been slightly altered and three references have been added

    MARKETING IN WESTERN VERSUS EASTERN CULTURE – COMPARING AND CONTRASTING BETWEEN THE U.S. AND JAPAN

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    In this paper we consider differences in marketing in Western vs. Eastern cultures and use the United States and Japan as the primary, but not exclusive, focus of our discussion. We first consider the general issue of companies trading internationally, and home in on the U.S. and Japan. We consider corporate cultures and examine a deeper look at the U.S. vs. Japan along a set of six dimensions, and we distinguish between internal and external aspects. We use case studies of three companies to illustrate our points, and end with a noting of our conclusions and managerial implications and some advice for companies seeking to enter the Japanese market
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