Precise predictions for same-sign W-boson scattering at the LHC

Alessandro Ballestrero, Benedikt Biedermann, Simon Brass, Ansgar Denner, Stefan Dittmaier, Rikkert Frederix, Pietro Govoni, Michele Grossi, Barbara Jäger, Alexander Karlberg, Ezio Maina, Mathieu Pellen, Giovanni Pelliccioli, Simon Plätzer, Michael Rauch, Daniela Rebuzzi, Jürgen Reuter, Vincent Rothe, Christopher Schwan, Hua-Sheng Shao, Pascal Stienemeier, Giulia Zanderighi, Marco Zaro, Dieter Zeppenfeld

Vector-boson scattering processes are of great importance for the current run-II and future runs of the Large Hadron Collider. The presence of triple and quartic gauge couplings in the process gives access to the gauge sector of the Standard Model (SM) and possible new-physics contributions there. To test any new-physics hypothesis, sound knowledge of the SM contributions is necessary, with a precision which at least matches the experimental uncertainties of existing and forthcoming measurements. In this article we present a detailed study of the vector-boson scattering process with two positively-charged leptons and missing transverse momentum in the final state. In particular, we first carry out a systematic comparison of the various approximations that are usually performed for this kind of process against the complete calculation, at LO and NLO QCD accuracy. Such a study is performed both in the usual fiducial region used by experimental collaborations and in a more inclusive phase space, where the differences among the various approximations lead to more sizeable effects. Afterwards, we turn to predictions matched to parton showers, at LO and NLO: we show that on the one hand, the inclusion of NLO QCD corrections leads to more stable predictions, but on the other hand the details of the matching and of the parton-shower programs cause differences which are considerably larger than those observed at fixed order, even in the experimental fiducial region. We conclude with recommendations for experimental studies of vector-boson scattering processes.

Particle Physics
External organisation(s)
Istituto Nazionale di Fisica Nucleare (INFN), Roma, Julius-Maximilians-Universität Würzburg, Universität Siegen, Albert-Ludwigs-Universität Freiburg, Technische Universität München, Universitá degli Studi di Milano, Università degli studi di Pavia, IBM Italia Spa Circonvallaz Idroscalo, Eberhard Karls Universität Tübingen, Universität Zürich (UZH), Università degli Studi di Torino, Karlsruher Institut für Technologie, Deutsches Elektronen-Synchrotron DESY, Université Paris IV - Paris-Sorbonne, Université Côte d'Azur, European Organization for Nuclear Research (CERN), NIKHEF (Nationaal instituut voor subatomaire fysica)
European Physical Journal C
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103012 High energy physics
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