9,748 research outputs found

    CP Violation in B Decays within QCD Factorization

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    We analyze the extraction of weak phases from CP violation in Bπ+πB\to\pi^+\pi^- decays. By combining the information on mixing induced CP violation in Bπ+πB\to\pi^+\pi^-, namely SππS_{\pi\pi}, with the precision observable sin2β\sin 2\beta obtained from the ``gold-plated''mode BψKSB\to\psi K_S, we propose the determination of the unitarity triangle. We also discuss alternative ways to analyze SππS_{\pi\pi} which can be useful if new physics affects BdB_d--Bˉd\bar B_d mixing. Predictions and uncertainties for rr and ϕ\phi in QCD factorization are examined in detail. It is pointed out that a simultaneous expansion in 1/mb1/m_b and 1/NC1/N_C leads to interesting simplifications. At first order infrared divergences are absent, while the most important effects are retained. Independent experimental tests of the factorization framework are briefly discussed.Comment: 3 pages; 2 figures; To appear in the proceedings of International Europhysics Conference on High-Energy Physics (HEP 2003), Aachen, Germany, 17-23 Jul 200

    CKM matrix from non-leptonic B-decays

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    We analyze the impact of the forthcoming CP-violating observables in the BsK+KB_s\to K^+ K^- system, combined with the precise measurement of sin2β\sin2\beta , in the extraction of the CKM matrix. Computing the penguin parameters (r,θ)(r, \theta) within QCD factorization yields a precise determination of (ρˉ,ηˉ)(\bar\rho, \bar\eta), reflected by a weak dependence on θ\theta, which is shown to be a second order effect. Using the SU(3)-flavour symmetry argument and the current BB-factories data provided by the Bdπ+πB_d \to \pi^+ \pi^- modes, we complement the BsK+KB_s \to K^+ K^- CP-violating observables in a variety of ways, in particular we find that SKK>0S_{KK}>0. Finally, we investigate systematically the SU(3)-symmetry breaking factor within QCD factorization.Comment: 4 pages; 4 figures (requires epsfig, psfrag); To appear in the proceedings of 32nd International Conference on High-Energy Physics (ICHEP 04), Beijing, China, 16-22 Aug 200

    Phenomenological study of the double radiative decay B>KγγB ->K\gamma\gamma

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    Using the operator product expansion (OPE) technique, we study the rare double radiative decay BKγγB\to K \gamma\gamma in the Standard Model (SM) and beyond. We estimate the short-distance (SD) contribution to the decay amplitude in a region of the phase space which is around the point where all decay products have energy mb/3\sim m_b/3 in the rest frame of the BB-meson. At lowest order in 1/mb1/m_b, the BKγγB\to K \gamma\gamma matrix element is then expressed in terms of the usual BKB\to K form factors known from semileptonic rare decays. The integrated SD branching ratio in the SM in the OPE region turns out to be ΔB(BKγγ)SMOPE1×109\Delta {\cal{B}}(B \to K \gamma \gamma)_{SM}^{OPE} \simeq 1 \times 10^{-9}. We work out the di-photon invariant mass distribution with and without the resonant background through BK{ηc,χc0}KγγB\to K \{\eta_c,\chi_{c0}\}\to K\gamma \gamma. In the SM, the resonance contribution is dominant in the region of phase space where the OPE is valid. On the other hand, the present experimental upper limit on Bsτ+τB_s \to \tau^+ \tau^- decays, leaves considerable room for New Physics (NP) in the one-particle-irreducible contribution to BKγγB\to K \gamma \gamma decays. In this case, we find that the SD BKγγB\to K \gamma \gamma branching ratio can be enhanced by one order of magnitude with respect to its SM value and the SD contribution can lie outside of the resonance peaks.Comment: 4 pages, 2 figures (requires epsfig, psfrag), To appear in the proceedings of the International Europhysics Conference on High Energy Physics, 21-27 July 2005, Lisboa, Portuga

    Behaviours of natural organic matter in membrane filtration for surface water treatment : a review

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    Membrane application in surface water treatment provides many advantages over conventional treatment. However, this effort is hampered by the fouling issue, which restricts its widespread application due to increases in hydraulic resistances, operational and maintenance costs, deterioration of productivity and frequency of membrane regeneration problems. This paper discusses natural organic matter (NOM) and its components as the major membrane foulants that occur during the water filtration process, possible fouling mechanisms relating to reversible and irreversible of NOM fouling, current techniques used to characterize fouling mechanisms and methods to control fouling. Feed properties, membrane characteristics, operational conditions and solution chemistry were also found to strongly influence the nature and extent of NOM fouling. Findings of such studies are highlighted. The understanding of the combined roles of controlling factors and the methods used is very important in order to choose and optimize the best technique and conditions during surface water treatment. The future potential of membrane application for NOM removal is also discussed

    Effects of Low pH on Lactate Dehydrogenase Kinetics of Diving and Nondiving Reptiles

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    The properties of lactate dehydrogenase were examined in two snake species, Nerodia rhombifera and Elaphe obsoleta, and a turtle species, Pseudemys scripta. Our purpose was to compare the LDH activity of reptiles with limited anaerobic capabilities with that of the well established diver Pseudemys. The Michaelis-Menten kinetics of LDH and its susceptibility to inhibition by elevated pyruvate concentrations were investigated in the brain and heart of the three species. All tissue incubations and enzyme activity determinations were done at a pH of 7.0 in order to stimulate a diving blood pH in the three species. In both tissues the LDH activity of the snakes was higher than that of Pseudemys at pyruvate concentrations ranging between .03 mM and .50 mM. The Km values of the snakes were lower than those of Pseudemys, suggesting a greater enzyme-substrate affinity in the snake tissues. The Vmax values were higher in the snake tissues indicating a faster conversion of substrate to product. Heart LDH activity was reduced to an equal extent by high pyruvate concentrations in each of the three species. Elaphe brain LDH was most susceptible to pyruvate inhibition, but Nerodia and Pseudemys brain LDH were inhibited to an equal extent. The results indicate that the kinetic behavior of brain and heart LDH of the three species is similar at a pH of 7.4 and a pH of 7.0. The results also suggest that the LDH of Pseudemys is no better adapted to withstand anaerobic conditions than that of Nerodia or Elaphe at a pH of 7.0

    Model Independent Bound on the Unitarity Triangle from CP Violation in B-> pi+ pi- and B-> psi K_S

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    We derive model independent lower bounds on the CKM parameters (1-rhobar) and etabar as functions of the mixing-induced CP asymmetry S in B-> pi+ pi- and sin(2 beta) from B->psi K_S. The bounds do not depend on specific results of theoretical calculations for the penguin contribution to B-> pi+ pi-. They require only the very conservative condition that a hadronic phase, which vanishes in the heavy-quark limit, does not exceed 90 degrees in magnitude. The bounds are effective if -sin(2 beta) < S < 1. Dynamical calculations indicate that the limits on rhobar and etabar are close to their actual values.Comment: 5 pages, 2 figure

    Finding of coefficients and oxidizable nitrogen from palm oil mill effluent (POME) for activated sludge models(ASMs)

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    Activated Sludge Models (ASMs) have been widely used as a basis for further model development in wastewater treatment processes. Values for parameters to be used are vital for the accuracy of the modeling approach. The objective of this study is to determine coefficients of the system, and oxidizable nitrogen of palm oil mill effluent (POME). A continuous stirred tank reactor (CSTR), with continuous flow for 20 hours, was used in this study. The DO profile for 11 days was monitored. The total, soluble, insoluble COD and soluble ammonia nitrogen were measured at the beginning and end of the experiment. Also, the coefficients and oxidizable nitrogen fractions are determined
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