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arXiv · 2102.11281

Signatures of toponium formation in LHC run 2 data

Benjamin Fuks·Kaoru Hagiwara·Kai Ma·Ya-Juan Zheng
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Abstract

We study reported deviations between observations and theoretical predictions associated with the production of a pair of di-leptonically decaying top quarks at the LHC, and we examine the possibility that they reflect a signal of toponium formation. We investigate the production by gluon fusion of a color-singlet spin-0 toponium $\eta_t$ bound state of a top and anti-top quark, that then decays di-leptonically ($gg\to\eta_t \to \bar\ell \ell b \bar{b} \nu \bar{\nu}$). We find strong correlations favoring the production of di-lepton systems featuring a small angular separation in azimuth and a small invariant mass. Although toponium production only contributes to 0.8% of the total top-quark pair-production cross section at the 13 TeV LHC, there is a possibility that it can account for observed excesses in the narrow edges of phase space. We propose a method to discover toponium formation by `reconstructing' both its top and anti-top quark constituents in the di-lepton channel.

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Benjamin Fuks, Kaoru Hagiwara, Kai Ma, Ya-Juan Zheng. 2021-02-22. Signatures of toponium formation in LHC run 2 data. https://doi.org/10.1103/physrevd.104.034023

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