1,825 research outputs found

    Right-Handed New Physics Remains Strangely Beautiful

    Full text link
    Current data on CP violation in B_d -> eta' K_S and B_d -> phi K_S, taken literally, suggest new physics contributions in b -> s transitions. Despite a claim to the contrary, we point out that right-handed operators with a single weak phase can account for both deviations thanks to the two-fold ambiguity in the extraction of the weak phase from the corresponding CP-asymmetry. This observation is welcome since large mixing in the right-handed sector is favored by many GUT models and frameworks which address the flavor puzzle. There are also interesting correlations with the B_s system which provide a way to test this scenario in the near future.Comment: 7 pages, 9 figures; published version: added 1 reference and 1 clarificatio

    Next-to-leading order QCD corrections to electroweak Zjj production in the POWHEGBOX

    Full text link
    We present an implementation of electroweak Z-boson production in association with two jets at hadron colliders in the POWHEG framework, a method that allows the interfacing of NLO-QCD calculations with parton-shower Monte Carlo programs. We focus on the leptonic decays of the weak gauge boson, and take photonic and non-resonant contributions to the matrix elements fully into account. We provide results for observables of particular importance for the suppression of QCD backgrounds to vector-boson fusion processes by means of central-jet-veto techniques. While parton-shower effects are small for most observables associated with the two hardest jets, they can be more pronounced for distributions that are employed in central-jet-veto studies.Comment: 12 pages, 5 figure

    Feynman Rules for the Rational Part of the Standard Model One-loop Amplitudes in the 't Hooft-Veltman Îł5\gamma_5 Scheme

    Full text link
    We study Feynman rules for the rational part RR of the Standard Model amplitudes at one-loop level in the 't Hooft-Veltman Îł5\gamma_5 scheme. Comparing our results for quantum chromodynamics and electroweak 1-loop amplitudes with that obtained based on the Kreimer-Korner-Schilcher (KKS) Îł5\gamma_5 scheme, we find the latter result can be recovered when our Îł5\gamma_5 scheme becomes identical (by setting g5s=1g5s=1 in our expressions) with the KKS scheme. As an independent check, we also calculate Feynman rules obtained in the KKS scheme, finding our results in complete agreement with formulae presented in the literature. Our results, which are studied in two different Îł5\gamma_5 schemes, may be useful for clarifying the Îł5\gamma_5 problem in dimensional regularization. They are helpful to eliminate or find ambiguities arising from different dimensional regularization schemes.Comment: Version published in JHEP, presentation improved, 41 pages, 10 figure

    Next-to-leading order QCD predictions for W+W+jj production at the LHC

    Full text link
    Because the LHC is a proton-proton collider, sizable production of two positively charged W-bosons in association with two jets is possible. This process leads to a distinct signature of same sign high-pt leptons, missing energy and jets. We compute the NLO QCD corrections to the QCD-mediated part of pp -> W+W+jj. These corrections reduce the dependence of the production cross-section on the renormalization and factorization scale to about +- 10 percent. We find that a large number of W+W+jj events contain a relatively hard third jet. The presence of this jet should help to either pick up the W+W+jj signal or to reject it as an unwanted background.Comment: 15 pages, 5 (lovely) figures, v3 accepted for publication in JHEP, corrects tables in appendi

    Toekomst van de pulsvisserij in de Waddenzee : een verkenning met relevantie voor de internationale Waddenzee en de Noordzeekustzone

    Get PDF
    Dit onderzoek is uitgevoerd in het kader van het EVF project Uitvoeringsprogramma Brede Visie duurzame visserij in de Waddenzee . Het rapport beschrijft de bevindingen van de verkenning Toekomst van de pulsvisserij in de Waddenzee. Het onderzoek is ook relevant voor pulsvisserij in de internationale Waddenzee en de Noordzeekustzone. Het onderzoek geeft antwoord op de vraag: Wat is de (potentiële) bijdrage van de garnalenpuls om te komen tot een gezonde garnalenvisserij en een rijke (Wadden)zee? Drie thema’s zijn hiervoor onderzocht: (1) wat is de ecologische meerwaarde van de garnalenpuls?, (2) Wat is de economische meerwaarde? en (3) Wat is de praktische inpasbaarheid van de techniek op de Waddenzee? Het rapport is opgesteld op basis van literatuurstudie, interviews en gesprekken met betrokkenen

    TF Target Mapper: A BLAST search tool for the identification of Transcription Factor target genes

    Get PDF
    BACKGROUND: In the current era of high throughput genomics a major challenge is the genome-wide identification of target genes for specific transcription factors. Chromatin immunoprecipitation (ChIP) allows the isolation of in vivo binding sites of transcription factors and provides a powerful tool for examining gene regulation. Crosslinked chromatin is immunoprecipitated with antibodies against specific transcription factors, thus enriching for sequences bound in vivo by these factors in the immunoprecipitated DNA. Cloning and sequencing the immunoprecipitated sequences allows identification of transcription factor target genes. Routinely, thousands of such sequenced clones are used in BLAST searches to map their exact location in the genome and the genes located in the vicinity. These genes represent potential targets of the transcription factor of interest. Such bioinformatics analysis is very laborious if performed manually and for this reason there is a need for developing bioinformatic tools to automate and facilitate it. RESULTS: In order to facilitate this analysis we generated TF Target Mapper (Transcription Factor Target Mapper). TF Target Mapper is a BLAST search tool allowing rapid extraction of annotated information on genes around each hit. It combines sequence cleaning/filtering, pattern searching and BLAST searches with extraction of information on genes located around each BLAST hit and comparisons of the output list of genes or gene ontology IDs with user-implemented lists. We successfully applied and tested TF Target Mapper to analyse sequences bound in vivo by the transcription factor GATA-1. We show that TF Target Mapper efficiently extracted information on genes around ChIPed sequences, thus identifying known (e.g. α-globin and ζ-globin) and potentially novel GATA-1 gene targets. CONCLUSION: TF Target Mapper is a very efficient BLAST search tool that allows the rapid extraction of annotated information on the genes around each hit. It can contribute to the comprehensive bioinformatic transcriptome/regulome analysis, by providing insight into the mechanisms of action of specific transcription factors, thus helping to elucidate the pathways these factors regulate

    Transversity and Transverse Spin in Nucleon Structure through SIDIS at Jefferson Lab

    Full text link
    The JLab 12 GeV upgrade with a proposed solenoid detector and the CLAS12 detector can provide the granularity and three-dimensional kinematic coverage in longitudinal and transverse momentum, 0.1≤x≤0.50.1\le x \le 0.5, 0.3≤z≤0.70.3 \le z \le 0.7 with PT≤1.5GeVP_T \le 1.5 {\rm GeV} to precisely measure the leading twist chiral-odd and TT-odd quark distribution and fragmentation functions in SIDIS. The large xx experimental reach of these detectors with a 12 GeV CEBAF at JLab makes it {\em ideal} to obtain precise data on the {\em valence-dominated} transversity distribution function and to access the tensor charge.Comment: 7 Pages, 2 figures. Summary of the working group on Transversity and Transverse Spin Physics, from the workshop, "Inclusive and Semi-Inclusive Spin Physics with High Luminosity and LargeAcceptance at 11 GeV", Thomas Jefferson National Accelerator Facility (JLAB), December 13-14, 2006, Jefferson Lab, Newport News, VA USA. Serves as input for the Nuclear Physics Long Range Plan on QCD and Hadron Physic
    • …
    corecore