644 research outputs found

    Study of BDπB\to D^{**} \pi decays

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    We investigate the production of the novel PP-wave mesons D0D^{*}_{0} and D1(D1)D^{\prime}_{1} (D_{1}), identified as JP=0+J^{P}=0^+ and 1+1^+, in heavy BB meson decays, respectively. With the heavy quark limit, we give our modelling wave functions for the scalar meson D0D^{*}_{0}. Based on the assumptions of color transparency and factorization theorem, we estimate the branching ratios of BD0πB\to D^{*}_{0} \pi decays in terms of the obtained wave functions. Some remarks on D1()D^{(\prime)}_{1} productions are also presented.Comment: 16 pages, 2 figures, Revtex4, to be published in Phys. Rev.

    Understanding the penguin amplitude in BϕKB \to \phi K decays

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    We calculate branching ratios for pure penguin decay modes, BϕKB\to \phi K decays using perturbative QCD approach. Our results of branching ratios are consistent with the experimental data and larger than those obtained from the naive factorization assumption and the QCD-improved factorization approach. This is due to a dynamical penguin enhancement in perturbative QCD approach.Comment: 7 pages, 2 figures, version to appear in PL

    Role of electromagnetic dipole operator in the electroweak penguin dominated vector meson decays of BB meson

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    The pure annihilation type decays Bd0ϕγB^0_d\to\phi\gamma and BsργB_s\to\rho\gamma receive only color suppressed penguin contributions with a very small branching ratio in the standard model. When we include the previously neglected electromagnetic dipole operator, the branching ratios can be enhanced one order magnitude larger than previous study using QCD factorization approach. That is BR(Bˉd0ϕγ)1×1011{\cal BR}(\bar B^0_d\to\phi\gamma)\simeq 1 \times 10^{-11} and BR(Bsργ)(616)×1010{\cal BR}(B_s\to\rho\gamma) \sim (6-16)\times 10^{-10}. The new effect can also give a large contribution, of order 10910^{-9}, to transverse polarization of BϕρB\to\phi\rho and BωϕB\to \omega\phi which is comparable to the longitudinal part. These effects can be detected in the LHCb experiment and the Super-B factories.Comment: Revised extensively. 8 pages, 4 figure

    Perturbative QCD analysis of BϕKB \to \phi K^* decays

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    We study the first observed charmless BVVB\to VV modes, the BϕKB\to\phi K^* decays, in perturbative QCD formalism. The obtained branching ratios B(BϕK)15×106B(B\to\phi K^*)\sim 15 \times 10^{-6} are larger than 9×106\sim 9\times 10^{-6} from QCD factorization. The comparison of the predicted magnitudes and phases of the different helicity amplitudes, and branching ratios with experimental data can test the power counting rules, the evaluation of annihilation contributions, and the mechanism of dynamical penguin enhancement in perturbative QCD, respectively.Comment: 14 pages, 2 tables, brief disscussion on hard sacle added, version to appear in PR

    Futher Study of CP Violation and Branching Ratios for B0ˉJ/ψKs\bar{B^0}\to J/\psi K_s and B0ˉϕKs\bar{B^0}\to \phi K_s in the Standard Model and Beyond

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    In this work we study the CP violation for B0ˉJ/ψKs\bar{B^0}\to J/\psi K_s and B0ˉϕKs\bar{B^0}\to \phi K_s up to leading and next-to-leading order QCD corrections in the standard model, two-Higgs-doublet model and the minimal supersymmetric extension of the standard model. We also study the effect of new physics on the branching ratios of these two decay modes. We find that within the parameter space constrained by the observation of the decay bsγb\to s\gamma, new physics does not affect the CP asymmetries greatly, and the prediction of new physics to the branching ratios of B0ˉJ/ψKs\bar{B^0}\to J/\psi K_s and B0ˉϕKs\bar{B^0}\to \phi K_s is the same as that of the standard model up to a minor discrepancy as far as the Yukama couplying constants are perturbative.Comment: some figures being reduced, accepted by J. Physics

    Pre-clinical characterization of GMP grade CCL21-gene modified dendritic cells for application in a phase I trial in Non-Small Cell Lung Cancer

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    <p>Abstract</p> <p>Background</p> <p>Our previous studies have demonstrated that transduction of human dendritic cells (DC) with adenovirus encoding secondary lymphoid chemokine, CCL21, led to secretion of biologically active CCL21 without altering DC phenotype or viability. In addition, intratumoral injections of CCL21-transduced DC into established murine lung tumors resulted in complete regression and protective anti-tumor immunity. These results have provided the rationale to generate a clinical grade adenoviral vector encoding CCL-21 for <it>ex vivo </it>transduction of human DC in order to assess intratumoral administration in late stage human lung cancer.</p> <p>Methods</p> <p>In the current study, human monocyte-derived DC were differentiated by exposure to GM-CSF and IL-4 from cryopreserved mononuclear cells obtained from healthy volunteers. Transduction with clinical grade adenoviral vector encoding CCL21 (1167 viral particles per cell) resulted in secretion of CCL21 protein.</p> <p>Results</p> <p>CCL21 protein production from transduced DC was detected in supernatants (24–72 hours, 3.5–6.7 ng/4–5 × 10<sup>6 </sup>cells). DC transduced with the clinical grade adenoviral vector were > 88% viable (n = 16), conserved their phenotype and maintained integral biological activities including dextran uptake, production of immunostimulatory cytokines/chemokines and antigen presentation. Furthermore, supernatant from CCL21-DC induced the chemotaxis of T2 cells <it>in vitro</it>.</p> <p>Conclusion</p> <p>Viable and biologically active clinical grade CCL21 gene-modified DC can be generated from cryopreserved PBMC.</p

    The Physics of K0Kˉ0K^0 -\bar K^0 Mixing: B^K\widehat{B}_K and ΔMLS\Delta M_{LS} in the Chiral Quark Model

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    We compute the B^K\widehat B_K parameter and the mass difference ΔMLS\Delta M_{LS} of the K0Kˉ0K^0-\bar K^0 system by means of the chiral quark model. The chiral coefficients of the relevant ΔS=2\Delta S=2 and ΔS=1\Delta S=1 chiral lagrangians are computed via quark-loop integration. We include the relevant effects of one-loop corrections in chiral perturbation theory. The final result is very sensitive to non-factorizable corrections of O(αSN)O(\alpha_S N) coming from gluon condensation. The size of the gluon condensate is determined by fitting the experimental value of the amplitude K+π+π0K^+ \to \pi^+\pi^0. By varying all the relevant parameters we obtain B^K=0.87±0.33 .\widehat{B}_K= 0.87 \pm 0.33\ . We evaluate within the model the long-distance contributions to ΔMLS\Delta M_{LS} induced by the double insertion of the ΔS=1\Delta S = 1 chiral lagrangian and study the interplay between short- and long-distance amplitudes. By varying all parameters we obtain ΔMLSth/ΔMLSexp=0.760.34+0.64.\Delta M_{LS}^{th}/\Delta M_{LS}^{exp} = 0.76 ^{+0.64}_{-0.34} . Finally, we investigate the phenomenological constraints on the Kobayashi-Maskawa parameter Im λt\lambda _t entering the determination of ϵ/ϵ\epsilon'/\epsilon.Comment: 31 pages, Latex file including 7 eps figures. Revised version to appear in Nucl. Phys.
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