79 research outputs found

    Search for Doubly-Charged Higgs Boson Production at HERA

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    A search for the single production of doubly-charged Higgs bosons H^{\pm \pm} in ep collisions is presented. The signal is searched for via the Higgs decays into a high mass pair of same charge leptons, one of them being an electron. The analysis uses up to 118 pb^{-1} of ep data collected by the H1 experiment at HERA. No evidence for doubly-charged Higgs production is observed and mass dependent upper limits are derived on the Yukawa couplings h_{el} of the Higgs boson to an electron-lepton pair. Assuming that the doubly-charged Higgs only decays into an electron and a muon via a coupling of electromagnetic strength h_{e \mu} = \sqrt{4 \pi \alpha_{em}} = 0.3, a lower limit of 141 GeV on the H^{\pm\pm} mass is obtained at the 95% confidence level. For a doubly-charged Higgs decaying only into an electron and a tau and a coupling h_{e\tau} = 0.3, masses below 112 GeV are ruled out.Comment: 15 pages, 3 figures, 1 tabl

    Measurement and QCD Analysis of Neutral and Charged Current Cross Sections at HERA

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    Première mesure des sections efficaces de courant chargé et neutre avec le faisceau de positrons polarisé à HERA II et analyses QCD-électrofaibles

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    In 2003--2004 the HERA collider delivered e+pe^+p collisions with a longitudinally polarised positron beam. We present the measurement of inclusive Neutral and Charged Current DIS cross section using the H1 detector. The total Charged Current cross section for Q2>400Q^2>400 GeV2^2, y400y400 GeV2^2, y<0,9y<0,9 donne \begin(eqnarray \sigma_(CC)(P=+0,33)&=& 34,67\mbox( pb )\pm 1,94\mbox( pb )\:(\mbox(stat))\pm 1,66\mbox( pb )\:(\mbox(sys)) \\ \sigma_(CC)(P=-0,40)&=& 13,80\mbox( pb )\pm 1,04\mbox( pb )\:(\mbox(stat))\pm 0,94\mbox( pb )\:(\mbox(sys)). \end(eqnarray) En accord avec le Modèle Standard qui prédit la proportionnalité de la section efficace avec la polarisation. Dans une deuxième partie, on réalise une analyse QCD des données de H1 pour extraire les densités de partons. Cette analyse est ensuite étendue à la détermination jointe des paramètres électrofaibles comme la masse du boson WW et des couplages des quarks au boson ZZ. Une analyse QCD globale des données de DIS et de Drell-Yan est réalisée, en particulier utilisée pour obtenir l'asymétrie de la mer étrange 01x(s(ˉs))(d)x=(1,8±3,8)×10(4)\int_0^1 x(s-\bar(s))\mathrm(d)x=(1,8\pm3,8)\times10^(-4). L'impact des nouvelles données de E866 sur les densités de quark à très grand xx est discuté. On obtient une extraction de la constante de couplage forte \alpha_s=0,1197\pm0,0008 \mbox( (exp)) ()^(+0,0005)_(-0,0007)\mbox( (mod))\pm0,006 \mbox( (th))

    H1 QCD analysis of inclusive cross section data

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    This contribution reviews the QCD analysis of the H1 inclusive DIS data. Flavor separated parton densities are extracted in a NLO QCD fit using neutral and charged current HERA I data. The results of a dedicated QCD analysis of the gluon and αs\alpha_s are also reviewed

    High Q**2 Structure Functions and Parton Distributions

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    This contribution reviews the main achievements in inclusive measurements made by the H1 and ZEUS collaborations during the first phase of HERA data taking. The QCD analysis of these data by both collaborations are described. The case for a common QCD analysis is briefly discussed, with an emphasis on the possible WW mass extraction

    High Q2\mathrm{Q^2} structure functions and parton distributions

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    This contribution reviews the main achievements in inclusive measurements made by the H1 and ZEUS collaborations during the first phase of HERA data taking. The QCD analysis of these data by both collaborations are described. The case for a common QCD analysis is briefly discussed, with an emphasis on the possible WW mass extraction

    Parton distribution functions in a fit of DIS and related data

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    Groupe H1We present a NLO analysis of DIS and related data, including high-statistics ν,νˉ\nu, \bar{\nu} cross section measurements. The parton distributions functions of the proton are extracted. A detailed study of the strange and antistrange densities is performed, and the charge symmetry of the strange sea is tested. We discuss the impact of the results on the NuTeV sin2θwsin^2 \theta_w puzzle

    Prebiotic effect on mood in obese patients is determined by the initial gut microbiota composition: a randomized, controlled trial

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    BACKGROUND AND AIMS: Metabolic and behavioural diseases, which are often related to obesity, have been associated to alterations of the gut microbiota considered as an interesting therapeutic target. We have analyzed in a cohort of obese patients treated with prebiotic inulin versus placebo the potential link between gut microbiota changes occurring upon intervention and their effect on psychological parameters (mood and cognition). METHODS: A randomized, single-blinded, multicentric, placebo-controlled trial was conducted in 106 obese patients assigned to two groups: prebiotic versus placebo, who received respectively 16 g/d of native inulin or maltodextrin combined with dietary advice to consume inulin-rich or -poor vegetables for 3 months as well as to restrict caloric intake. Anthropometric measurements, food intake, psychological questionnaires, serum measures, and fecal microbiome sequencing were performed before and after the intervention. RESULTS: Inulin supplementation in obese subjects had moderate beneficial effect on emotional competence and cognitive flexibility. However, an exploratory analysis revealed that some patients exhibiting specific microbial signature -elevated Coprococcus levels at baseline- were more prone to benefit from prebiotic supplementation in terms of mood. Positive responders toward inulin intervention in term of mood also displayed worse metabolic and inflammatory profiles at baseline (increased levels of IL-8, insulin resistance and adiposity). CONCLUSION: This study shows that inulin intake can be helpful to improve mood in obese subjects exhibiting a specific microbial profile. The present work highlights some microbial, metabolic and inflammatory features (IL-8, insulin resistance) which can predict or mediate the beneficial effects of inulin on behaviour in obesity. Food4gut, clinicaltrial.gov: NCT03852069, https://clinicaltrials.gov/ct2/show/NCT03852069
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