Simulating toponium formation signals at the LHC

Abstract We present a method to simulate toponium formation events at the LHC using the Green’s function of non-relativistic QCD in the Coulomb gauge, which governs the momentum distribution of top quarks in the presence of the QCD potential. This Green’s function can be employed to re-weight any matrix elements relevant for $$t{\bar{t}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>t</mml:mi> <mml:mover> <mml:mrow> <mml:mi>t</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> </mml:math> production and decay processes where a colour-singlet top–antitop pair is produced in the S -wave at threshold. As an example, we study the formation of $$\eta _t$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>η</mml:mi> <mml:mi>t</mml:mi> </mml:msub> </mml:math> toponium states in the gluon fusion channel at the LHC, combining the re-weighted matrix elements with parton showering.