269 research outputs found

    Intrinsic charm in a matched general-mass scheme

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    The FONLL general-mass variable-flavour number scheme provides a framework for the matching of a calculation in which a heavy quark is treated as a massless parton to one in which the mass dependence is retained throughout. We describe how the usual formulation of FONLL can be extended in such a way that the heavy quark parton distribution functions are freely parameterized at some initial scale, rather than being generated entirely perturbatively. We specifically consider the case of deep-inelastic scattering, in view of applications to PDF determination, and the possible impact of a fitted charm quark distribution on F2cF_2^c is assessed.Comment: 16 pages, 5 figures. Final version, to be published in Physics Letters B. Typo in eq 13 corrected, minor clarifications adde

    Parton distributions with threshold resummation

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    We construct a set of parton distribution functions (PDFs) in which fixed-order NLO and NNLO calculations are supplemented with soft-gluon (threshold) resummation up to NLL and NNLL accuracy respectively, suitable for use in conjunction with any QCD calculation in which threshold resummation is included at the level of partonic cross sections. These resummed PDF sets, based on the NNPDF3.0 analysis, are extracted from deep-inelastic scattering, Drell-Yan, and top quark pair production data, for which resummed calculations can be consistently used. We find that, close to threshold, the inclusion of resummed PDFs can partially compensate the enhancement in resummed matrix elements, leading to resummed hadronic cross-sections closer to the fixed-order calculation. On the other hand, far from threshold, resummed PDFs reduce to their fixed-order counterparts. Our results demonstrate the need for a consistent use of resummed PDFs in resummed calculations.Comment: 43 pages, 17 figures, accepted for publication in JHE

    Tailoring CD19xCD3-DART exposure enhances T-cells to eradication of B-cell neoplasms.

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    Many patients with B-cell malignancies can be successfully treated, although tumor eradication is rarely achieved. T-cell-directed killing of tumor cells using engineered T-cells or bispecific antibodies is a promising approach for the treatment of hematologic malignancies. We investigated the efficacy of CD19xCD3 DART bispecific antibody in a broad panel of human primary B-cell malignancies. The CD19xCD3 DART identified 2 distinct subsets of patients, in which the neoplastic lymphocytes were eliminated with rapid or slow kinetics. Delayed responses were always overcome by a prolonged or repeated DART exposure. Both CD4 and CD8 effector cytotoxic cells were generated, and DART-mediated killing of CD4+ cells into cytotoxic effectors required the presence of CD8+ cells. Serial exposures to DART led to the exponential expansion of CD4 + and CD8 + cells and to the sequential ablation of neoplastic cells in absence of a PD-L1-mediated exhaustion. Lastly, patient-derived neoplastic B-cells (B-Acute Lymphoblast Leukemia and Diffuse Large B Cell Lymphoma) could be proficiently eradicated in a xenograft mouse model by DART-armed cytokine induced killer (CIK) cells. Collectively, patient tailored DART exposures can result in the effective elimination of CD19 positive leukemia and B-cell lymphoma and the association of bispecific antibodies with unmatched CIK cells represents an effective modality for the treatment of CD19 positive leukemia/lymphoma

    Research highlights from the 2018 European Respiratory Society International Congress: airway disease.

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    The annual European Respiratory Society (ERS) International Congress (held in Paris in 2018) was once again a platform for discussion of the highest-quality scientific research, cutting-edge techniques and innovative new therapies within the respiratory field. This article discusses only some of the high-quality research studies presented at this year's Congress, with a particular focus on airway diseases including asthma, chronic obstructive pulmonary disease (COPD), bronchiectasis and cough, as presented through Assembly 5 of the ERS (Airway Diseases: Asthma and COPD). The authors establish the key take-home messages of these studies, compare their findings and place them in the context of current understanding

    Les bulles « robustes »:Pourquoi il faut construire des logements en région parisienne

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    « Bulle » ou « pas bulle » ? La question taraude les observateurs et les acteurs du marchĂ© immobilier français. Nous examinons dans cet article les Ă©lĂ©ments empiriques et thĂ©oriques qui expliquent la hausse des prix rĂ©cente et sa rĂ©sistance aux retournements conjoncturels. En combinant la notion de bulle Ă©conomique, les arguments de l’économie spatiale et une analyse d’économie politique, nous suggĂ©rons que la valorisation importante de l’immobilier en France est le rĂ©sultat d’une logique rationnelle et conforte les intĂ©rĂȘts des acteurs locaux. DĂšs lors, la forte valorisation peut ĂȘtre considĂ©rĂ©e comme une « bulle robuste », Ă  mĂȘme de rĂ©sister Ă  des chocs importants. Cette bulle organise un transfert intergĂ©nĂ©rationnel et peut avoir des effets positifs. Elle peut Ă©galement renforcer la sĂ©grĂ©gation spatiale, alimenter les inĂ©galitĂ©s territoriales et empĂȘcher d’exploiter les Ă©conomies d’agglomĂ©ration possibles. L’analyse est dĂ©taillĂ©e sur la rĂ©gion Ile-de-France oĂč ces phĂ©nomĂšnes sont particuliĂšrement marquĂ©s

    Updated Higgs cross section at approximate N3LO

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    We update our estimate of the cross section for Higgs production in gluon fusion at next- to-next-to-next-to-leading order (N3LO) in \u3b1s in view of the recent full computation of the result in the soft limit for infinite top mass, which determines a previously unknown constant. We briefly discuss the phenomenological implications. Results are available through the updated version of the ggHiggs code

    Charm in Deep-Inelastic Scattering

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    We show how to extend systematically the FONLL scheme for inclusion of heavy quark mass effects in DIS to account for the possible effects of an intrinsic charm component in the nucleon. We show that when there is no intrinsic charm, FONLL is equivalent to S-ACOT to any order in perturbation theory, while when an intrinsic charm component is included FONLL is identical to ACOT, again to all orders in perturbation theory. We discuss in detail the inclusion of top and bottom quarks to construct a variable flavour number scheme, and give explicit expressions for the construction of the structure functions F2cF^c_2, FLcF^c_L and F3cF^c_3 to NNLO
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