480 research outputs found

    Charmless BsPP,PV,VVB_s\to PP, PV, VV Decays Based on the six-quark Effective Hamiltonian with Strong Phase Effects II

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    We provide a systematic study of charmless BsPP,PV,VVB_s \to PP, PV, VV decays (PP and VV denote pseudoscalar and vector mesons, respectively) based on an approximate six-quark operator effective Hamiltonian from QCD. The calculation of the relevant hard-scattering kernels is carried out, the resulting transition form factors are consistent with the results of QCD sum rule calculations. By taking into account important classes of power corrections involving "chirally-enhanced" terms and the vertex corrections as well as weak annihilation contributions with non-trivial strong phase, we present predictions for the branching ratios and CP asymmetries of BsB_s decays into PP, PV and VV final states, and also for the corresponding polarization observables in VV final states. It is found that the weak annihilation contributions with non-trivial strong phase have remarkable effects on the observables in the color-suppressed and penguin-dominated decay modes. In addition, we discuss the SU(3) flavor symmetry and show that the symmetry relations are generally respected

    Vanishing Viscous Limits for 3D Navier-Stokes Equations with A Navier-Slip Boundary Condition

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    In this paper, we investigate the vanishing viscosity limit for solutions to the Navier-Stokes equations with a Navier slip boundary condition on general compact and smooth domains in R3\mathbf{R}^3. We first obtain the higher order regularity estimates for the solutions to Prandtl's equation boundary layers. Furthermore, we prove that the strong solution to Navier-Stokes equations converges to the Eulerian one in C([0,T];H1(Ω))C([0,T];H^1(\Omega)) and L^\infty((0,T)\times\o), where TT is independent of the viscosity, provided that initial velocity is regular enough. Furthermore, rates of convergence are obtained also.Comment: 45page

    Heavy-quark energy loss in pQCD and SYM plasmas

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    We consider heavy-quark energy loss and pT-broadening in a strongly-coupled N=4 Super Yang Mills (SYM) plasma, and the problem of finite-extend matter is addressed. When expressed in terms of the appropriate saturation momentum, one finds identical parametric forms for the energy loss in pQCD and SYM theory, while pT-broadening is radiation dominated in SYM theory and multiple scattering dominated in pQCD.Comment: 5 pages, 2 figures, Proceedings of the IIIrd Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions (HotQuarks08), Estes Park, USA, August 18-23 200

    Charm multiplicity and the branching ratios of inclusive charmless b quark decays in the general two-Higgs-doublet models

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    In the framework of general two-Higgs-doublet models, we calculate the branching ratios of various inclusive charmless b decays by using the low energy effective Hamiltonian including next-to-leading order QCD corrections, and examine the current status and the new physics effects on the determination of the charm multiplicity ncn_c and semileptonic branching ratio BSLB_{SL}. Within the considered parameter space, the enhancement to the ratio BR(bsg)BR(b \to s g) due to the charged-Higgs penguins can be as large as a factor of 8 (3) in the model III (II), while the ratio BR(bnocharm)BR(b \to no charm) can be increased from the standard model prediction of 2.49% to 4.91% (2.99%) in the model III (II). Consequently, the value of BSLB_{SL} and ncn_c can be decreased simultaneously in the model III. The central value of BSLB_{SL} will be lowered slightly by about 0.003, but the ratio ncn_c can be reduced significantly from the theoretical prediction of nc=1.28±0.05n_c= 1.28 \pm 0.05 in the SM to nc=1.23±0.05n_c= 1.23 \pm 0.05, 1.18±0.051.18 \pm 0.05 for mH+=200,100m_{H^+}=200, 100 GeV, respectively. We find that the predicted ncn_c and the measured ncn_c now agree within roughly one standard deviation after taking into account the effects of gluonic charged Higgs penguins in the model III with a relatively light charged Higgs boson.Comment: 25 pages, Latex file, axodraw.sty, 6 figures. Final version to be published in Phys.Rev.

    B_c meson rare decays in the light-cone quark model

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    We investigate the rare decays BcDs(1968)ˉB_c \rightarrow D_s(1968) \ell \bar{\ell} and BcDs(2317)ˉB_c\rightarrow D_s^*(2317) \ell \bar{\ell} in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful to investigating the structure of BcB_c meson and to testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC.Comment: 9 pages, 11 figures, version accepted for publication in EPJ

    Flagellin/TLR5 stimulate myeloid progenitors to enter lung tissue and to locally differentiate into macrophages

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    Toll-like receptor 5 (TLR5) is the receptor of bacterial Flagellin. Reportedly, TLR5 engagement helps to combat infections, especially at mucosal sites, by evoking responses from epithelial cells and immune cells. Here we report that TLR5 is expressed on a previously defined bipotent progenitor of macrophages (M phi s) and osteoclasts (OCs) that resides in the mouse bone marrow (BM) and circulates at low frequency in the blood. In vitro, Flagellin promoted the generation of M phi s, but not OCs from this progenitor. In vivo, M phi/OC progenitors were recruited from the blood into the lung upon intranasal inoculation of Flagellin, where they rapidly differentiated into M phi s. Recruitment of the M phi/OC progenitors into the lung was likely promoted by the CCL2/CCR2 axis, since the progenitors expressed CCR2 and type 2 alveolar epithelial cells (AECs) produced CCL2 upon stimulation by Flagellin. Moreover, CCR2 blockade reduced migration of the M phi/OC progenitors toward lung lavage fluid (LLF) from Flagellin-inoculated mice. Our study points to a novel role of the Flagellin/TLR5 axis in recruiting circulating M phi/OC progenitors into infected tissue and stimulating these progenitors to locally differentiate into M phi s. The progenitor pathway to produce M phi s may act, next to monocyte recruitment, to fortify host protection against bacterial infection at mucosal sites.Tumorimmunolog

    Study of f_0(980) and f_0(1500) from B_s \to f_0(980)\pi, f_0(1500)\pi Decays

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    In this paper, we analyze the scalar mesons f0(980)f_0(980) and f0(1500)f_0(1500) from the decays Bˉs0f0(980)π0,f0(1500)π0\bar B^0_s \to f_0(980)\pi^0, f_0(1500)\pi^0 within Perturbative QCD approach. From the leading order calculations, we find that (a) in the allowed mixing angle ranges, the branching ratio of Bˉs0f0(980)π0\bar B^0_s\to f_0(980)\pi^0 is about (1.01.6)×107(1.0\sim1.6)\times 10^{-7}, which is smaller than that of Bˉs0f0(980)K0\bar B^0_s\to f_0(980)K^0 (the difference is a few times even one order); (b) the decay Bˉs0f0(1500)π0\bar B^0_s \to f_0(1500)\pi^0 is better to distinguish between the lowest lying state or the first excited state for f0(1500)f_0(1500), because the branching ratios for two scenarios have about one-order difference in most of the mixing angle ranges; and (c) the direct CP asymmetries of Bˉs0f0(1500)π0\bar B^0_s \to f_0(1500)\pi^0 for two scenarios also exists great difference. In scenario II, the variation range of the value ACPdir(Bˉs0f0(1500)π0){\cal A} ^{dir}_{CP}(\bar B^0_s \to f_0(1500)\pi^0) according to the mixing angle is very small, except for the values corresponding to the mixing angles being near 9090^\circ or 270270^\circ, while the variation range of ACPdir(Bˉs0f0(1500)π0){\cal A} ^{dir}_{CP}(\bar B^0_s \to f_0(1500)\pi^0) in scenario I is very large. Compared with the future data for the decay Bˉs0f0(1500)π0\bar B^0_s \to f_0(1500)\pi^0, it is ease to determine the nature of the scalar meson f0(1500)f_0(1500).Comment: 16 pages, 3 figures, Revte

    Charmless hadronic decays BPP,PV,VVB \to PP, PV, VV and new physics effects in the general two-Higgs doublet models

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    Based on the low-energy effective Hamiltonian with the generalized factorization, we calculate the new physics contributions to the branching ratios of the two-body charmless hadronic decays of BuB_u and BdB_d mesons induced by the new gluonic and electroweak charged-Higgs penguin diagrams in the general two-Higgs doublet models (models I, II and III). Within the considered parameter space, we find that: (a) the new physics effects from new gluonic penguin diagrams strongly dominate over those from the new γ\gamma- and Z0Z^0- penguin diagrams; (b) in models I and II, new physics contributions to most studied B meson decay channels are rather small in size: from -15% to 20%; (c) in model III, however, the new physics enhancements to the penguin-dominated decay modes can be significant, (30200)\sim (30 -200)%, and therefore are measurable in forthcoming high precision B experiments; (d) the new physics enhancements to ratios {\cal B}(B \to K \etap) are significant in model III, (3570)\sim (35 -70)%, and hence provide a simple and plausible new physics interpretation for the observed unexpectedly large B \to K \etap decay rates; (e) the theoretical predictions for B(BK+π){\cal B}(B \to K^+ \pi) and B(BK0π+){\cal B}(B \to K^0 \pi^+) in model III are still consistent with the data within 2σ2\sigma errors; (f) the significant new physics enhancements to the branching ratios of BK0π0,Kη,K+π,K+ϕ,K0ω,K+ϕB \to K^0 \pi^0, K^* \eta, K^{*+} \pi^-, K^+ \phi, K^{*0} \omega, K^{*+} \phi and K0ϕK^{*0} \phi decays are helpful to improve the agreement between the data and the theoretical predictions; (g) the theoretical predictions of B(BPP,PV,VV){\cal B}(B \to PP, PV, VV) in the 2HDM's are generally consistent with experimental measurements and upper limits (9090% C.L.)Comment: 55 pages, Latex file, 17 PS and EPS figures. With minor corrections, final version to be published in Phys.Rev. D. Repot-no: PKU-TH-2000-4

    B^0-\bar{B}^0 mixing and B \to X_s \gamma decay in the third type 2HDM: effects of NLO QCD contributions

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    In this paper, we calculated the next-to-leading order (NLO) new physics contributions to the mass splitting \dmd and the branching ratio \brbxsga induced by the charged Higgs loop diagrams in the third type of two-Higgs-doublet models (model III) and draw the constraints on the free parameters of model III. For the model III under consideration, we found that (a) an upper limit |\ltt|\leq 1.7 is obtained from the precision data of \dmd=0.502 \pm 0.007 ps^{-1}, while |\ltt| \approx 0.5 is favored phenomenologicaly; (b) for BXsγB \to X_s \gamma decay, the NLO QCD contributions tend to cancel the LO new physics contributions; (c) a light charged Higgs boson with a mass around or even less than 200 GeV is still allowed at NLO level by the measured branching ratio \brbxsga: numerically, 188 \leq \mh \leq 215 GeV for (|\ltt|,|\lbb|)=(0.5,18); (d) the NLO QCD contributions tend to cancel the LO contributions effectively, the lower limit on \mh is consequently decreased by about 200 GeV; (e) the allowed region of \mh will be shifted toward heavy mass end for a non-zero relative phase θ\theta between the Yukawa couplings \ltt and \lbb. The numerical results for the conventional model II are also presented for the sake of a comparison.Comment: 42 pages, 18 eps figures, Revtex, new references adde
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