142 research outputs found

    Three-particle contributions to the renormalisation of B-meson light-cone distribution amplitudes

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    We study light-cone distribution amplitudes of heavy-light systems, such as a B-meson. By an explicit computation, we determine how two-parton distribution amplitudes mix with three-parton ones at one loop: \phi_+ is shown to mix only into itself, whereas \phi_- mixes with the difference of three-parton distribution amplitudes \Psi_A-\Psi_V. We determine the corresponding anomalous dimension and we check the gauge independence of our result by considering a general covariant gauge. Finally, we comment on some implications of our result for phenomenological models of these distribution amplitudes.Comment: 21 pages, 5 figures, some comments and 2 references added, except for typesetting matches version published in JHE

    Hsa-miR-210-3p expression in breast cancer and its putative association with worse outcome in patients treated with Docetaxel

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    MicroRNA-210-3p is the most prominent hypoxia regulated microRNA, and it has been found significantly overexpressed in different human cancers. We performed the expression analysis of miR-210-3p in a retrospective cohort of breast cancer patients with a median follow-up of 76 months (n = 283). An association between higher levels of miR-210-3p and risk of disease progression (HR: 2.13, 95%CI: 1.33-3.39, P = 0.002) was found in the subgroup of patients treated with Epirubicin and Cyclophosphamide followed by Docetaxel. Moreover, a cut off value of 20.966 established by ROC curve analyses allowed to discriminate patients who developed distant metastases with an accuracy of 85% at 3- (AUC: 0.870, 95%CI: 0.690-1.000) and 83% at 5-years follow up (AUC: 0.832, 95%CI: 0.656-1.000). Whereas the accuracy in discriminating patients who died for the disease was of 79.6% at both 5- (AUC: 0.804, 95%CI: 0.517-1.000) and 10-years (AUC: 0.804. 95%CI: 0.517-1.000) follow-up. In silico analysis of miR-210-3p and Docetaxel targets provided evidence for a putative molecular cross-talk involving microtubule regulation, drug efflux metabolism and oxidative stress response. Overall, our data point to the miR-210-3p involvement in the response to therapeutic regimens including Docetaxel in sequential therapy with anthracyclines, suggesting it may represent a predictive biomarker in breast cancer patients

    Light-cone sum rules for BπB \to \pi form factors revisited

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    We reconsider and update the QCD light-cone sum rules for BπB\to \pi form factors. The gluon radiative corrections to the twist-2 and twist-3 terms in the correlation functions are calculated. The MSˉ\bar{MS} bb-quark mass is employed, instead of the one-loop pole mass used in the previous analyses. The light-cone sum rule for fBπ+(q2)f^+_{B\pi}(q^2) is fitted to the measured q2q^2-distribution in BπlνlB\to \pi l \nu_l, fixing the input parameters with the largest uncertainty: the Gegenbauer moments of the pion distribution amplitude. For the BπB\to \pi vector form factor at zero momentum transfer we predict fBπ+(0)=0.260.03+0.04f^+_{B\pi}(0)= 0.26^{+0.04}_{-0.03}. Combining it with the value of the product VubfBπ+(0)|V_{ub}f^+_{B\pi}(0)| extracted from experiment, we obtain Vub=(3.5±0.4±0.2±0.1)×103|V_{ub}|=(3.5\pm 0.4\pm 0.2\pm 0.1) \times 10^{-3}. In addition, the scalar and penguin BπB\to \pi form factors fBπ0(q2)f^0_{B\pi}(q^2) and fBπT(q2)f^T_{B\pi}(q^2) are calculated.Comment: 33 pages, 7 figures, one figure and a few comments added, version to appear in JHE

    Strong coupling of excited heavy mesons

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    We compute the strong coupling constant GBBπ  (GDDπ)G_{B^{**} B \pi} \; (G_{D^{**} D \pi}), where BB^{**} (DD^{**}) is the 0+0^+ PP-wave bqˉ  (cqˉ)b \bar q \; (c \bar q) state, by QCD sum rules and by light-cone sum rules. The two methods give compatible results in the limit mQm_Q \to \infty, with a rather large value of the coupling constant. We apply the results to the calculation of the hadronic widths of the positive parity BB and DD states and to the chiral loop contribution to the ratio fDs/fDf_{D_s}/f_D.Comment: 31 pages, RevTeX, 4 figures appended as uuencoded fil

    BD()B \to D^{(*)} Form Factors from QCD Light-Cone Sum Rules

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    We derive new QCD sum rules for BDB\to D and BDB\to D^* form factors. The underlying correlation functions are expanded near the light-cone in terms of BB-meson distribution amplitudes defined in HQET, whereas the cc-quark mass is kept finite. The leading-order contributions of two- and three-particle distribution amplitudes are taken into account. From the resulting light-cone sum rules we calculate all B\to \Dst form factors in the region of small momentum transfer (maximal recoil). In the infinite heavy-quark mass limit the sum rules reduce to a single expression for the Isgur-Wise function. We compare our predictions with the form factors extracted from experimental B\to \Dst l \nu_l decay rates fitted to dispersive parameterizations.Comment: 20 pages, 6 figures; one reference, one figure and several comments added; version to appear in European Physical Journal

    Hsa-miR-155-5p Up-Regulation in Breast Cancer and Its Relevance for Treatment With Poly[ADP-Ribose] Polymerase 1 (PARP-1) Inhibitors

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    miR-155-5p is a well-known oncogenic microRNA, showing frequent overexpression in human malignancies, including breast cancer. Here, we show that high miR-155-5p levels are associated with unfavorable prognostic factors in two independent breast cancer cohorts (CSS cohort, n = 283; and TCGA-BRCA dataset, n = 1,095). Consistently, miR-155-5p results as differentially expressed in the breast cancer subgroups identified by the surrogate molecular classification in the CSS cohort and the PAM50 classifier in TCGA-BRCA dataset, with the TNBC and HER2-amplified tumors carrying the highest levels. Since the analysis of TCGA-BC dataset also demonstrated a significant association between miR-155-5p levels and the presence of mutations in homologous recombination (HR) genes, we hypothesized that miR-155-5p might affect cell response to the PARP-1 inhibitor Olaparib. As expected, miR-155-5p ectopic overexpression followed by Olaparib administration resulted in a greater reduction of cell viability as compared to Olaparib administration alone, suggesting that miR-155-5p might induce a synthetic lethal effect in cancer cells when coupled with PARP-1-inhibition. Overall, our data point to a role of miR-155-5p in homologous recombination deficiency and suggest miR-155-5p might be useful in predicting response to PARP1 inhibitors in the clinical setting

    Analysis of the radiative decays among the charmonium states

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    In this article, we study the radiative decays among the charmonium states with the heavy quark effective theory, and make predictions for the ratios among the radiative decay widths of an special multiplet to another multiplet. The predictions can be confronted with the experimental data in the future and put additional constraints in identifying the XX, YY, ZZ charmonium-like mesons.Comment: 12 pages, revised revisio

    Analysis of the Three-Body BD+Dπ0B \to D^+ D^- \pi^0 Decay

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    The decay process BD+Dπ0B\to D^+ D^- \pi^0 is an interesting channel for the investigation of CP violating effects in the bb- sector. We write down a decay amplitude constrained by a low-energy theorem, which also includes the contribution of resonant SS- and PP-wave beauty and charmed mesons, and we determine the relevant matrix elements in the infinite heavy quark mass limit, assuming the factorization ansatz. We estimate the rate of the decay: B(BD+Dπ0)1×103{\cal B}(B \to D^+ D^- \pi^0)\simeq 1 \times 10^{-3}. We also analyze the time-independent and time-dependent differential decay distributions, concluding that a signal for this process should be observed at the B-factories. Finally, we give an estimate of the decay rate of the Cabibbo-favoured process BD+DKSB\to D^+ D^- K_S.Comment: LaTex, 20 pages, 4 figure

    Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

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    Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius AA. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio
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