Scalar production and decay to top quarks including interference effects at NLO in QCD in an EFT approach
Abstract
Scalar and pseudoscalar resonances decaying to top quarks are common predictions in several scenarios beyond the standard model (SM) and are extensively searched for by LHC experiments. Challenges on the experimental side require optimising the strategy based on accurate predictions. Firstly, QCD corrections are known to be large both for the SM QCD background and for the pure signal scalar production. Secondly, leading order and approximate nexttoleading order (NLO) calculations indicate that the interference between signal and background is large and drastically changes the lineshape of the signal, from a simple peak to a peakdip structure. Therefore, a robust prediction of this interference at NLO accuracy in QCD is necessary to ensure that higherorder corrections do not alter the lineshapes. We compute the exact NLO corrections, assuming a pointlike coupling between the scalar and the gluons and consistently embedding the calculation in an effective field theory within an automated framework, and present results for a representative set of beyond the SM benchmarks. The results can be further matched to parton shower simulation, providing more realistic predictions. We find that NLO corrections are important and lead to a significant reduction of the uncertainties. We also discuss how our computation can be used to improve the predictions for physics scenarios where the gluonscalar loop is resolved and the effective approach is less applicable.
 Publication:

arXiv eprints
 Pub Date:
 July 2017
 arXiv:
 arXiv:1707.06760
 Bibcode:
 2017arXiv170706760B
 Keywords:

 High Energy Physics  Phenomenology;
 High Energy Physics  Experiment
 EPrint:
 32 pages, 17 figures