244 research outputs found

    A search for the decay modes B+/- to h+/- tau l

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    We present a search for the lepton flavor violating decay modes B+/- to h+/- tau l (h= K,pi; l= e,mu) using the BaBar data sample, which corresponds to 472 million BBbar pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and l candidates, we are able to fully determine the tau four-momentum. The resulting tau candidate mass is our main discriminant against combinatorial background. We see no evidence for B+/- to h+/- tau l decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10^-5.Comment: 15 pages, 7 figures, submitted to Phys. Rev.

    Measurement of Exclusive B Decays to Final States Containing a Charmed Baryon

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    Using data collected by the CLEO detector in the Upsilon(4S) region, we report new measurements of the exclusive decays of B mesons into final states of the type Lambda_c^+ p-bar n(pi), where n=0,1,2,3. We find signals in modes with one, two and three pions and an upper limit for the two body decay Lambda_c^+ pbar. We also make the first measurements of exclusive decays of B mesons to Sigma_c p-bar n(pi), where n=0,1,2. We find signals in modes with one and two pions and an upper limit for the two body decay Sigma_c p-bar. Measurements of these modes shed light on the mechanisms involved in B decays to baryons.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PR

    Observation of the Ωc0\Omega_{c}^{0} Charmed Baryon at CLEO

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    The CLEO experiment at the CESR collider has used 13.7 fb1^{-1} of data to search for the production of the Ωc0\Omega_c^0 (css-ground state) in e+ee^{+}e^{-} collisions at s10.6\sqrt{s} \simeq 10.6 {\rm GeV}. The modes used to study the Ωc0\Omega_c^0 are Ωπ+\Omega^- \pi^+, Ωπ+π0\Omega^- \pi^+ \pi^0, ΞKpi+π+\Xi^- K^- pi^+ \pi^+, Ξ0Kpi+\Xi^0 K^- pi^+, and Ωπ+ππ+\Omega^- \pi^+ \pi^- \pi^+. We observe a signal of 40.4±\pm9.0(stat) events at a mass of 2694.6±\pm2.6(stat)±\pm1.9(syst) {\rm MeV/c2c^2}, for all modes combined.Comment: 10 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Witten index in supersymmetric 3d theories revisited

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    We have performed a direct calculation of Witten index in N = 1,2,3 supersymmetric Yang-Mills Chern-Simons 3d theories. We do it in the framework of Born-Oppenheimer (BO) approach by putting the system into a small spatial box and studying the effective Hamiltonian depending on the zero field harmonics. At the tree level, our results coincide with the results of Witten, but there is a difference in the way the loop effects are implemented. In Witten's approach, one has only take into account the fermion loops, which bring about a negative shift of the (chosen positive at the tree level) Chern-Simons coupling k. As a result, Witten index vanishes and supersymmetry is broken at small k. In the effective BO Hamiltonian framework, fermion, gluon and ghost loops contribute on an equal footing. Fermion loop contribution to the effective Hamiltonian can be evaluated exactly, and their effect amounts to the negative shift k -> k - h/2 for N =1 and k -> k - h for N = 2,3 in the tree-level formulae for the index. In our approach, with rather natural assumptions on the structure of bosonic corrections, the shift k -> k + h brought about by the gluon loops also affects the index. Since the total shift of k is positive or zero, Witten index appears to be nonzero at nonzero k, and supersymmetry is not broken. We discuss possible reasons for such disagreement.Comment: A bug in Eq.(2.20) is fixe

    Dalitz Analysis of the Decay D0Kπ+π0D^{0}\to K^{-}\pi^{+}\pi^{0}

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    We use data collected with the CLEO II detector to perform a high-statistics measurement of the resonant substructure in D0Kπ+π0D^0 \to K^-\pi^+\pi^0 decays. We find the Dalitz Plot is well represented by a combination of seven quasi-two-body decay channels (Kˉ0π0\bar{K}^{*0} \pi^0, KρK^- \rho, Kπ+K^{*-} \pi^+, K0(1430)π+K^*_0(1430)^-\pi^+, Kˉ0(1430)0π0\bar{K}^*_0(1430)^0 \pi^0, Kρ+(1700)K^- \rho^+(1700), and K(1680)π+K^*(1680)^- \pi^+), plus a small non-resonant component. Using the amplitudes and phases from this analysis, we calculate an integrated CP asymmetry of 0.031±0.086-0.031 \pm 0.086.Comment: 32 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, Version to appear in Phys. Rev.

    Study of (B)over-bar -> X(u)l(v)over-bar decays in B(B)over-bar events tagged by a fully reconstructed B-meson decay and determination of vertical bar V-ub vertical bar

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    We report measurements of partial branching fractions for inclusive charmless semileptonic B decays B̄→

    Elliptic Operators on Closed Manifolds

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    Towards human cell simulation

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    none14siThe faithful reproduction and accurate prediction of the phe-notypes and emergent behaviors of complex cellular systems are among the most challenging goals in Systems Biology. Although mathematical models that describe the interactions among all biochemical processes in a cell are theoretically feasible, their simulation is generally hard because of a variety of reasons. For instance, many quantitative data (e.g., kinetic rates) are usually not available, a problem that hinders the execution of simulation algorithms as long as some parameter estimation methods are used. Though, even with a candidate parameterization, the simulation of mechanistic models could be challenging due to the extreme computational effort required. In this context, model reduction techniques and High-Performance Computing infrastructures could be leveraged to mitigate these issues. In addition, as cellular processes are characterized by multiple scales of temporal and spatial organization, novel hybrid simulators able to harmonize different modeling approaches (e.g., logic-based, constraint-based, continuous deterministic, discrete stochastic, spatial) should be designed. This chapter describes a putative unified approach to tackle these challenging tasks, hopefully paving the way to the definition of large-scale comprehensive models that aim at the comprehension of the cell behavior by means of computational tools.noneSpolaor, Simone; Gribaudo, Marco; Iacono, Mauro; Kadavy, Tomas; Oplatková, Zuzana Komínková; Mauri, Giancarlo; Pllana, Sabri; Senkerik, Roman; Stojanovic, Natalija; Turunen, Esko; Viktorin, Adam; Vitabile, Salvatore; Zamuda, Aleš; Nobile, Marco S.Spolaor, Simone; Gribaudo, Marco; Iacono, Mauro; Kadavy, Tomas; Oplatková, Zuzana Komínková; Mauri, Giancarlo; Pllana, Sabri; Senkerik, Roman; Stojanovic, Natalija; Turunen, Esko; Viktorin, Adam; Vitabile, Salvatore; Zamuda, Aleš; Nobile, Marco S
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