5,854 research outputs found

    Measurement of ϕs\phi_s at D{\O} Experiment

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    Recent measurements of the D\O\ experiment related to the search for new phenomena beyond the Standard Model are reviewed. The new measurement of the like-sign dimuon charge asymmetry reveals a 3.2σ\sigma deviation from the SM prediction, while the updated study of the BsJ/ψϕB_s \to J/\psi \phi decay demonstrates a better agreement with the SM. All experimental results on the CPCP violation in mixing are currently consistent with each other. The D\O\ collaboration has much more statistics to analyze, and all these results can be significantly improved in the future.Comment: Proceedings of CKM2010, the 6th International Workshop on the CKM Unitarity Triangle, University of Warwick, UK, 6-10 September 201

    Heavy Flavour results from Tevatron

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    The CDF and D0 experiments finalize the analysis of their full statistics collected in the ppˉp \bar p collisions at a center-of-mass energy of s=1.96\sqrt{s} = 1.96 TeV at the Fermilab Tevatron collider. This paper presents several new results on the properties of hadrons containing heavy bb- and cc-quarks obtained by both collaborations. These results include the search for the rare decays B0,Bs0μ+μB^0, B^0_s \to \mu^+ \mu^- (CDF), the study of CP asymmetry in BsJψϕB_s \to J\psi \phi decay (CDF, D0), the measurement of the like-sign dimuon charge asymmetry (D0), the measurement of CP asymmetry in D0K+KD^0 \to K^+K^- and D0π+πD^0 \to \pi^+\pi^- decays (CDF), and the new measurement of the BsDs()+Ds()B_s \to D_s^{(*)+} D_s^{(*)-} branching fraction (CDF). Both experiments still expect to produce more results on the properties of heavy flavours.Comment: Contribution to the XLVIIth Rencontres de Moriond session devoted to Electroweak Interactions and Unified Theorie

    Neutrinos that violate CPT, and the experiments that love them

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    Recently we proposed a framework for explaining the observed evidence for neutrino oscillations without enlarging the neutrino sector, by introducing CPT violating Dirac masses for the neutrinos. In this paper we continue the exploration of the phenomenology of CPT violation in the neutrino sector. We show that our CPT violating model fits the existing SuperKamiokande data at least as well as the standard atmospheric neutrino oscillation models. We discuss the challenge of measuring CP violation in a neutrino sector that also violates CPT. We point out that the proposed off-axis extension of MINOS looks especially promising in this regard. Finally, we describe a method to compute CPT violating neutrino effects by mocking them up with analog matter effects.Comment: 17 pages, 3 eps figure

    Causality in Spin Foam Models

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    We compute Teitelboim's causal propagator in the context of canonical loop quantum gravity. For the Lorentzian signature, we find that the resultant power series can be expressed as a sum over branched, colored two-surfaces with an intrinsic causal structure. This leads us to define a general structure which we call a ``causal spin foam''. We also demonstrate that the causal evolution models for spin networks fall in the general class of causal spin foams.Comment: 19 pages, LaTeX2e, many eps figure

    Production of Polarized Vector Mesons off Nuclei

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    Using the light-cone QCD dipole formalism we investigate manifestations of color transparency (CT) and coherence length (CL) effects in electroproduction of longitudinally (L) and transversally (T) polarized vector mesons. Motivated by forthcoming data from the HERMES experiment we predict both the A and Q^2 dependence of the L/T- ratios, for rho^0 mesons produced coherently and incoherently off nuclei. For an incoherent reaction the CT and CL effects add up and result in a monotonic A dependence of the L/T-ratio at different values of Q^2. On the contrary, for a coherent process the contraction of the CL with Q^2 causes an effect opposite to that of CT and we expect quite a nontrivial A dependence, especially at Q^2 >> m_V^2.Comment: Revtex 24 pages and 14 figure