Bump-hunting in LHC ttbar events

Abstract

We demonstrate that a purposefully normalised NNLO top pair invariant mass differential spectrum can have very small theoretical uncertainty and, in particular, a small sensitivity to the top quark mass. Such observable can thus be a very effective bump-hunting tool for resonances decaying to top pair events during LHC Run II and beyond. To illustrate how the approach works, we concentrate on one specific example of current interest, namely, the possible 750 GeV di-gamma excess resonance Phi. Considering only theoretical uncertainties, we demonstrate that it is possible to distinguish pp -> Phi -> tt signals studied in the recent literature [Hespel, Maltoni and Vryonidou, arXiv:1606.04149] from the pure SM background with very high significance. Alternatively, in case of non-observation, a strong upper limit on the decay rate Phi -> tt can be placed.

arXiv comment8 pages, 6 figures, analytic fits attached, plot on top-mass sensitivity for the invariant mass distribution added, appendix on top-mass sensitivity of differential distributions added, minor additional changes and comments, matches published version

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Cited by in corpus (10)

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• Pinning down the large-x gluon with NNLO top-quark pair differential distributions
• NNLO QCD corrections to leptonic observables in top-quark pair production and decay
• Interference Effects in $t\bar{t}$ Production at the LHC as a Window on New Physics
• Analytic results for deep-inelastic scattering at NNLO QCD with the nested soft-collinear subtraction scheme
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• NNLO PDFs driven by top-quark data
• Higgs interference effects in top-quark pair production in the 1HSM