Multi-lepton signatures of additional scalar bosons beyond the Standard Model at the LHC

Abstract

Following a prediction made in Refs.~\cite{vonBuddenbrock:2015ema,Kumar:2016vut,vonBuddenbrock:2016rmr}, this paper focuses on multi-lepton signatures arising from two new hypothetical scalar bosons, $H$ and $S$, at the Large Hadron Collider (LHC). These two new bosons are an extension to the Standard Model (SM) and interact with the SM Higgs boson, $h$. We consider two production modes for $H$, one being gluon fusion and the other being in association with top quarks. The $H\to Sh$ decay mode is considered, where leptonic final states are studied. The CP properties of $S$ are characterised by considering effective couplings derived from dimension six operators through $SWW$ vertices. The nature of the $S$ boson is considered in two separate contexts. Firstly in a simplified model, it is considered to have Higgs-like couplings. Secondly, we consider a heavy neutrino model and its interactions with the $Z,W$ and $S$ bosons. The predictions of the models are compared both to ATLAS and CMS results at $\sqrt{s}=8$ and $13$~TeV, where appropriate. The data is interpreted using a simplified model where all the signal comes from $H\to Sh$, assuming $S$ to be Higgs-like, $m_H=270$~GeV and $m_S=150$~GeV. The combined result yields gives a best fit value for the parameter ${\beta }_g$ (the strength of the Yukawa coupling of $H$ to top quarks), ${\beta }_g^2=1.38\pm 0.22$. A number of regions of the phase space are suggested to the experiments for further exploration.

30 pages, updated version, to be appear in J. Phys. G

References in corpus (2)

• The compatibility of LHC Run 1 data with a heavy scalar of mass around 270\,GeV
• The production of the heavy scalar H in association with top and anti-top quarks

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• Wrong Sign Bottom Yukawa in Low Energy Supersymmetry
• The use of Generative Adversarial Networks to characterise new physics in multi-lepton final states at the LHC
• Machine learning approach for the search of resonances with topological features at the Large Hadron Collider