5,500 research outputs found

    Dissection of the Candida albicans class I chitin synthase promoters

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    We acknowledge financial support from the Biotechnology and Biological Sciences Research Council (10161), Medical Research Council (New Investigator Award to C.A.M.), the European Community FUNGALWALL and SIGNALPATH initiatives and the Wellcome Trust.Peer reviewedPublisher PD

    Faddeev study of heavy baryon spectroscopy

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    We investigate the structure of heavy baryons containing a charm or a bottom quark. We employ a constituent quark model successful in the description of the baryon-baryon interaction which is consistent with the light baryon spectra. We solve exactly the three-quark problem by means of the Faddeev method in momentum space. Heavy baryon spectrum shows a manifest compromise between perturbative and nonperturbative contributions. The flavor dependence of the one-gluon exchange is analyzed. We assign quantum numbers to some already observed resonances and we predict the first radial and orbital excitations of all states with J=1/2J=1/2 or 3/2. We combine our results with heavy quark symmetry and lowest-order SU(3) symmetry breaking to predict the masses and quantum numbers of six still non-measured ground-state beauty baryons.Comment: 22 pages, 4 figures, 8 tables. Accepted for publication in J. Phys.

    High resolution study of the Lambda p final state interaction in the reaction p + p -> K+ + (Lambda p)

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    The reaction pp -> K+ + (Lambda p) was measured at Tp=1.953 GeV and Theta = 0 deg with a high missing mass resolution in order to study the Lambda p final state interaction. The large final state enhancement near the Lambda p threshold can be described using the standard Jost-function approach. The singlet and triplet scattering lengths and effective ranges are deduced by fitting simultaneously the Lambda p invariant mass spectrum and the total cross section data of the free Lambda p scattering.Comment: submitted to Physics Letters B, 10 pages, 3 figure

    Prospects for terahertz imaging the human skin cancer with the help of gold-nanoparticles-based terahertz-to-infrared converter

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    The design is suggested, and possible operation parameters are discussed, of an instrument to inspect a skin cancer tumour in the terahertz (THz) range, transferring the image into the infrared (IR) and making it visible with the help of standard IR camera. The central element of the device is the THz-to-IR converter, a Teflon or silicon film matrix with embedded 8.5 nm diameter gold nanoparticles. The use of external THz source for irradiating the biological tissue sample is presumed. The converter's temporal characteristics enable its performance in a real-time scale. The details of design suited for the operation in transmission mode (in vitro) or on the human skin in reflection mode {in vivo) are specified.Comment: To be published in the proceedings of the FANEM2018 workshop - Minsk, 3-5 June 201

    Search for the X(1812) in B±K±ωϕB^{\pm} \to K^{\pm} \omega \phi

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    We report on a search for the X(1812) state in the decay B±K±ωϕB^{\pm} \to K^{\pm} \omega \phi with a data sample of 657×106657\times10^6 BBˉB\bar{B} pairs collected with the Belle detector at the KEKB e+ee^+e^- collider. No significant signal is observed. An upper limit B(B±K±X(1812),X(1812)ωϕ)<3.2×107{\cal B}(B^{\pm} \to K^{\pm} X(1812),X(1812) \to \omega \phi)<3.2\times 10^{-7} (90% C.L.) is determined. We also constrain the three-body decay branching fraction to be B(B±K±ωϕ){\cal B}(B^{\pm} \to K^{\pm} \omega \phi) << 1.9 ×106\times 10^{-6} (90% C.L.).Comment: 5pages,2 figures(3 figure files). submitted to PRD(RC

    Study of J/psi to p pbar, Lambda Lambdabar and observation of eta_c to Lambda Lambdabar at Belle

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    We study the baryonic charmonium decays of B mesons, B+ to etac K+ and B+ to J/psi K+, where the etac and J/psi subsequently decay into a p pbar or Lambda Lambdabar pair. We measure the J/psi to p pbar, Lambda Lambdabar anisotropy parameters, alpha_B = -0.60 +- 0.13 +-0.14 (p pbar), -0.44 +- 0.51 +- 0.31 (Lambda Lambdabar) and compare to results from e+e- to J/psi formation experiments. We also report the first observation of etac to Lambda Lambdabar. The measured branching fraction is B(etac to Lambda Lambdabar) = (0.87 +0.24 -0.21(stat) +0.09 -0.14(syst) +- 0.27 (PDG)) x 10^-3. This study is based on a 357 fb^-1 data sample recorded on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.Comment: 8 pages, two figures (4 figure files), an update of hep-ex/0509020 for journal submissio

    Measurements of CP Violation in B0Dπ+B^0 \to D^{*-}\pi^+ and B0Dπ+B^0 \to D^- \pi^+ Decays

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    We report measurements of time dependent decay rates for B0D()π+B^0 \to D^{(*)-}\pi^+ decays and extraction of CP violation parameters that depend on ϕ3\phi_3. Using fully reconstructed D()πD^{(*)}\pi events and partially reconstructed DπD^{*}\pi events from a data sample that contains 386 million BBˉB\bar{B} pairs that was collected near the Υ(4S)\Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric energy e+ee^+ e^- collider, we obtain the CP violation parameters S+(D()π)S^+ (D^{(*)}\pi) and S(D()π)S^- (D^{(*)}\pi). We obtain S+(Dπ)=0.049±0.020(stat)±0.011(sys)S^+ (D^* \pi) = 0.049 \pm 0.020(\mathrm{stat}) \pm 0.011(\mathrm{sys}), S(Dπ)=0.031±0.019(stat)±0.011(sys)S^- (D^* \pi) = 0.031 \pm 0.019(\mathrm{stat}) \pm 0.011(\mathrm{sys}), and S+(Dπ)=0.031±0.030(stat)±0.012(sys)S^+ (D \pi) = 0.031 \pm 0.030(\mathrm{stat}) \pm 0.012(\mathrm{sys}), S(Dπ)=0.068±0.029(stat)±0.012(sys)S^- (D \pi) = 0.068 \pm 0.029(\mathrm{stat}) \pm 0.012(\mathrm{sys}). These results are an indication of CP violation in B0Dπ+B^0 \to D^{*-}\pi^+ and B0Dπ+B^0 \to D^- \pi^+ decays at the 2.5σ2.5 \sigma and 2.2σ2.2 \sigma levels, respectively. If we use the values of RD()πR_{D^{(*)}\pi} that are derived using assumptions of factorization and SU(3) symmetry, the branching fraction measurements for the Ds()πD_s^{(*)} \pi modes, and lattice QCD calculations, we can restrict the allowed region of sin(2ϕ1+ϕ3)|\sin (2\phi_1 + \phi_3)| to be above 0.44 and 0.52 at 68% confidence level from the DπD^* \pi and DπD \pi modes, respectively.Comment: 14 pages, 12 figures, submitted to Physical Review

    Observation of Radiative Decay D0ϕγD^0 \to \phi \gamma

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    We report the observation of the decay D0ϕγD^{0} \to \phi \gamma with a statistical significance of 5.4σ5.4\sigma in 78.1 \ifb of data collected by the Belle experiment at the KEKB e+ee^+ e^- collider. This is the first observation of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and color-suppressed decays D0ϕπ0D^0 \to \phi \pi^0, ϕη\phi \eta are also observed for the first time. We measure branching fractions \br(D^{0} \to \phi \gamma) = [ 2.60^{+0.70}_{-0.61} \stat {}^{+0.15}_{-0.17} \syst ] \times 10^{-5}, \br(D^{0} \to \phi \pi^{0}) = [ 8.01 \pm 0.26 \stat \pm 0.47 \syst ] \times 10^{-4}, and \br(D^{0} \to \phi \eta) = [ 1.48 \pm 0.47 \stat \pm 0.09 \syst ] \times 10^{-4}.Comment: 9 pages, 4 figures, Belle Preprint 2003-24, KEK Preprint 2003-75, updated version of BELLE-CONF-0346 (contributed paper to the XXI International Symposium on Lepton and Photon Interactions at High Energies,Fermilab Aug 11-16,2003). to appear in Phys. Rev. Let

    Measurement of phi_3 with Dalitz plot analysis of B+ -> D(*)K(*)+ decay

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    We present a measurement of the unitarity triangle angle phi_3 using a Dalitz plot analysis of the K0_S pi+ pi- decay of the neutral D meson from the B+- -> D(*)K(*)+- process. The method employs the interference between D0 and D0bar to extract the angle phi_3, strong phase Delta and the ratio r of suppressed and allowed amplitudes. We apply this method to a 357 fb-1 data sample collected by the Belle experiment. The analysis uses three modes: B+ -> DK+, B+ -> D*K+ with D* -> Dpi0, and B+ -> DK*+ with K*+ -> K0_S pi+, as well as the corresponding charge-conjugate modes. From a combined maximum likelihood fit to the three modes, we obtain phi_3=53+15-18(stat)+-3(syst)+-9(model) degrees. The corresponding two standard deviation interval is 8<phi_3<111 degrees.Comment: 18 pages, 6 figures, 7 tables. To be submitted to Phys. Rev.
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