Full NLO QCD corrections to off-shell <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>t</mml:mi><mml:mover accent="true"><mml:mrow><mml:mi>t</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover><mml:mi>b</mml:mi><mml:mover accent="true"><mml:mrow><mml:mi>b</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover></mml:mrow></mml:math> production
Ansgar Denner, Jean-Nicolas Lang, Mathieu Pellen
Abstract
In this article, we report on the computation of the next-to-leading order (NLO) QCD corrections to $\mathrm{p}\mathrm{p}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}{\mathrm{e}}^{+}{\ensuremath{\nu}}_{\mathrm{e}}\overline{b}b\overline{b}b$ at the LHC, which is an irreducible background to $\mathrm{p}\mathrm{p}\ensuremath{\rightarrow}t\overline{t}\mathrm{H}(\ensuremath{\rightarrow}b\overline{b})$. This is the first time that a full NLO computation for a $2\ensuremath{\rightarrow}8$ process with 6 external strongly interacting partons is made public. No approximations are used, and all off-shell and interference effects are taken into account. Cross sections and differential distributions from the full computation are compared to results obtained by using a double-pole approximation for the top quarks. The difference between the full calculation and the one using the double-pole approximation is in general below 5% but can reach 10% in some regions of phase space.