3,680 research outputs found

    Identification of placental transforming growth factor-beta and bikunin metabolites as contaminants of pharmaceutical human chorionic gonadotrophin preparations by proteomic techniques

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    This paper is the first to identify the novel bio-molecules found in pregnancy urine and commonly contaminate clinical grade hCG preparation extracted from urine reported to have anti-HIV/HIV Kaposis . Professor Iles was the Principal Investigator

    Long-range two-body final-state interactions and direct CP asymmetry in {B}^{+}\to{\pi}^{+} {K}^{0} decay

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    We present a calculation of the direct CP asymmetry, ACPdirA_{CP}^{dir}, for the process B+→π+K0B^+ \to \pi^+ K^0 including the effects of long-range inelastic final-state interactions (FSI). We admit three channels in our calculation: B+→(π+K0),(ηK+)B^+ \to (\pi^+ K^0), (\eta K^+), and (Ds+Dˉ0)(D_s^+ \bar{D}^0). The strong scattering is described in terms of Pomeron and Regge exchanges. We find that the direct CP asymmetry is enhanced by a factor of ∼3\sim 3 as a result of FSI, but remains well short of the claims of (10 - 20)% in recent literature. A critical assessment of papers claiming large CP asymmetries is also presented.Comment: 21 pages, latex, no figures. Added the charge-exchange channel {B}^{+}\to {\pi}^{0} {K}^{+}. Expanded the discussion section. To be published in Phys. Rev.

    Extraction of VubV_{ub} from the Decay B→πlνB\to \pi l \nu

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    We develop the perturbative QCD formalism including Sudakov effects for semi-leptonic BB meson decays. We evaluate the differential decay rate of B→πlνB\to \pi l \nu, and find that the perturbative calculation is reliable for the energy fraction of the pion above 0.3. Combining predictions from the soft pion theorems, we extract the value of the matrix element ∣Vub∣|V_{ub}| which is roughly 2.7×10−32.7\times 10^{-3}.Comment: 10 pages, CCUTH-94-05, IP-ASTP-13-9

    The decay constants of pseudoscalar mesons in a relativistic quark model

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    The decay constants of pseudoscalar mesons are calculated in a relativistic quark model which assumes that mesons are made of a valence quark antiquark pair and of an effective vacuum like component. The results are given in terms of quark masses and of some free parameters entering the expression of the internal wave functions of the mesons. By using the pion and kaon decay constants Fπ+=130.7 MeV, FK+=159.8 MeVF_{\pi^+}=130.7~MeV,~F_{K^+}=159.8~MeV to fix the parameters of the model one gets 60 MeV≤FD+≤185 MeV, 95 MeV≤FDs≤230 MeV, 80 MeV≤FB+≤205 MeV60~MeV\leq F_{D^+}\leq 185~MeV,~95~MeV\leq F_{D_s}\leq230~MeV,~80~MeV\leq F_{B^+}\leq205~MeV for the light quark masses mu=5.1 MeV, md=9.3 MeV, ms=175 MeVm_u=5.1~MeV,~m_d=9.3~MeV,~m_s=175~MeV and the heavy quark masses in the range: 1. GeV≤mc≤1.6 GeV, 4.1 GeV≤mb≤4.5 GeV1.~GeV\leq m_c\leq1.6~GeV,~4.1~GeV\leq m_b\leq4.5~GeV. In the case of light neutral mesons one obtains with the same set of parameters Fπ0≈138 MeV, Fη≈ 130 MeV,Fη′≈ 78 MeVF_{\pi^0}\approx 138~MeV,~F_\eta\approx~130~MeV,F_{\eta'} \approx~78~MeV. The values are in agreement with the experimental data and other theoretical results.Comment: 11 pages, LaTe

    Bc Meson Formfactors and Bc-->PV Decays Involving Flavor Dependence of Transverse Quark Momentum

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    We present a detailed analysis of the Bc form factors in the BSW framework, by investigating the effects of the flavor dependence on the average transverse quark momentum inside a meson. Branching ratios of two body decays of Bc meson to pseudoscalar and vector mesons are predicted.Comment: 18 pages, 5 figure

    High-resolution x-ray study of the nematic - smectic-A and smectic-A - smectic-C transitions in 8barS5-aerosil gels

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    The effects of dispersed aerosil nanoparticles on two of the phase transitions of the thermotropic liquid crystal material 4-n-pentylphenylthiol-4'-n-octyloxybenzoate 8barS5 have been studied using high-resolution x-ray diffraction techniques. The aerosils hydrogen bond together to form a gel which imposes a weak quenched disorder on the liquid crystal. The smectic-A fluctuations are well characterized by a two-component line shape representing thermal and random-field contributions. An elaboration on this line shape is required to describe the fluctuations in the smectic-C phase; specifically the effect of the tilt on the wave-vector dependence of the thermal fluctuations must be explicitly taken into account. Both the magnitude and the temperature dependence of the smectic-C tilt order parameter are observed to be unaffected by the disorder. This may be a consequence of the large bare smectic correlation length in the direction of modulation for this transition. These results show that the understanding developed for the nematic to smectic-A transition for octylcyanobiphenyl (8CB) and octyloxycyanobiphenyl (8OCB) liquid crystals with quenched disorder can be extended to quite different materials and transitions.Comment: 7 pages, 8 figure

    The B(Bs)→D(s)PB(B_s)\to D_{(s)} P, D(s)VD_{(s)} V, D(s)∗PD_{(s)}^{*}P and D(s)∗VD_{(s)}^{*}V decays in the perturbative QCD approach

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    Two-body non-leptonic charmed decays B(s)→D(s)PB_{(s)} \to D_{(s)}P, D(s)∗PD_{(s)}^*P, D(s)VD_{(s)}V and D(s)∗VD_{(s)}^*V are analyzed in perturbative QCD approach, where PP and VV denote the light pseudoscalar meson and vector meson, respectively. We test the DD meson wave function by a χ2\chi^2 fit with experimental data of six B→DPB\to DP channels. We give the branching ratios of all the charmed B decay channels, most of which agree with experiments amazingly well. The predicted BsB_s decays can be confronted with the future experimental data. By straightforward calculations, our pQCD approach gives the right relative strong phase of a2/a1a_2/a_1 with experiments. We also predict the percentage of transverse polarizations in B(s)→D∗VB_{(s)} \to D^* V decay channels.Comment: 25 pages, 4 figure

    Applicability of Perturbative QCD to B→DB\to D Decays

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    We examine the applicability of perturbative QCD to BB meson decays into DD mesons. We find that the perturbative QCD formalism, which includes Sudakov effects at intermediate energy scales, is applicable to the semi-leptonic decay B→DlνB\to D l\nu, when the DD meson recoils fast. Following this conclusion, we analyze the two-body non-leptonic decays B→DπB\to D\pi and B→DDsB\to DD_s. By comparing our predictions with experimental data, we extract the matrix element ∣Vcb∣=0.044|V_{cb}|=0.044.Comment: 18 pages in Latex, figures are available upon reques

    Quark Mass Hierarchies, Flavor Mixing and Maximal CP-Violation

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    Flavor mixing and the quark mass spectrum are intimately related. In view of the observed strong hierarchy of the quark and lepton masses and of the flavor mixing angles it is argued that the description of flavor mixing must take this into account. One particular interesting way to describe the flavor mixing emerges, which is particularly suited for models of quark mass matrices based on flavor symmetries. We conclude that the unitarity triangle important for BB physics should be close to or identical to a rectangular triangle. CPCP violation is maximal in this sense.Comment: 21 latex page
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