422 research outputs found

    Physics, Topology, Logic and Computation: A Rosetta Stone

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    In physics, Feynman diagrams are used to reason about quantum processes. In the 1980s, it became clear that underlying these diagrams is a powerful analogy between quantum physics and topology: namely, a linear operator behaves very much like a "cobordism". Similar diagrams can be used to reason about logic, where they represent proofs, and computation, where they represent programs. With the rise of interest in quantum cryptography and quantum computation, it became clear that there is extensive network of analogies between physics, topology, logic and computation. In this expository paper, we make some of these analogies precise using the concept of "closed symmetric monoidal category". We assume no prior knowledge of category theory, proof theory or computer science.Comment: 73 pages, 8 encapsulated postscript figure

    Determination of the Form Factors for the Decay B0 --> D*-l+nu_l and of the CKM Matrix Element |Vcb|

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    We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element Vcb|V_{cb}| and of the parameters ρ2\rho^2, R1R_1, and R2R_2, which fully characterize the form factors of the B0D+νB^0 \to D^{*-}\ell^{+}\nu_\ell decay in the framework of HQET, based on a sample of about 52,800 B0D+νB^0 \to D^{*-}\ell^{+}\nu_\ell decays recorded by the BABAR detector. The kinematical information of the fully reconstructed decay is used to extract the following values for the parameters (where the first errors are statistical and the second systematic): ρ2=1.156±0.094±0.028\rho^2 = 1.156 \pm 0.094 \pm 0.028, R1=1.329±0.131±0.044R_1 = 1.329 \pm 0.131 \pm 0.044, R2=0.859±0.077±0.022R_2 = 0.859 \pm 0.077 \pm 0.022, F(1)Vcb=(35.03±0.39±1.15)×103\mathcal{F}(1)|V_{cb}| = (35.03 \pm 0.39 \pm 1.15) \times 10^{-3}. By combining these measurements with the previous BABAR measurements of the form factors which employs a different technique on a partial sample of the data, we improve the statistical accuracy of the measurement, obtaining: ρ2=1.179±0.048±0.028,R1=1.417±0.061±0.044,R2=0.836±0.037±0.022,\rho^2 = 1.179 \pm 0.048 \pm 0.028, R_1 = 1.417 \pm 0.061 \pm 0.044, R_2 = 0.836 \pm 0.037 \pm 0.022, and F(1)Vcb=(34.68±0.32±1.15)×103. \mathcal{F}(1)|V_{cb}| = (34.68 \pm 0.32 \pm 1.15) \times 10^{-3}. Using the lattice calculations for the axial form factor F(1)\mathcal{F}(1), we extract Vcb=(37.74±0.35±1.25±1.441.23)×103|V_{cb}| =(37.74 \pm 0.35 \pm 1.25 \pm ^{1.23}_{1.44}) \times 10^{-3}, where the third error is due to the uncertainty in F(1)\mathcal{F}(1)

    Study of the Exclusive Initial-State Radiation Production of the DDˉD \bar D System

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    A study of exclusive production of the DDˉD \bar D system through initial-state r adiation is performed in a search for charmonium states, where D=D0D=D^0 or D+D^+. The D0D^0 mesons are reconstructed in the D0Kπ+D^0 \to K^- \pi^+, D0Kπ+π0D^0 \to K^- \pi^+ \pi^0, and D0Kπ+π+πD^0 \to K^- \pi^+ \pi^+ \pi^- decay modes. The D+D^+ is reconstructed through the D+Kπ+π+D^+ \to K^- \pi^+ \pi^+ decay mode. The analysis makes use of an integrated luminosity of 288.5 fb1^{-1} collected by the BaBar experiment. The DDˉD \bar D mass spectrum shows a clear ψ(3770)\psi(3770) signal. Further structures appear in the 3.9 and 4.1 GeV/c2c^2 regions. No evidence is found for Y(4260) decays to DDˉD \bar D, implying an up per limit \frac{\BR(Y(4260)\to D \bar D)}{\BR(Y(4260)\to J/\psi \pi^+ \pi^-)} < 7.6 (95 % confidence level)

    Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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    Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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    Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search

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    Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

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    Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

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    Measurement of the Z boson differential cross section in transverse momentum and rapidity in proton-proton collisions at 8 TeV

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    We present a measurement of the Z boson differential cross section in rapidity and transverse momentum using a data sample of pp collision events at a centre-of-mass energy s=8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The Z boson is identified via its decay to a pair of muons. The measurement provides a precision test of quantum chromodynamics over a large region of phase space. In addition, due to the small experimental uncertainties in the measurement the data has the potential to constrain the gluon parton distribution function in the kinematic regime important for Higgs boson production via gluon fusion. The results agree with the next-to-next-to-leading-order predictions computed with the fewz program. The results are also compared to the commonly used leading-order MadGraph and next-to-leading-order powheg generators. © 2015 CERN for the benefit of the CMS Collaboration
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