Associated top quark pair production with a heavy boson: differential cross sections at NLO + NNLL accuracy
Anna Kulesza, Leszek Motyka, Daniel Schwartländer, Tomasz Stebel, Vincent Theeuwes
Abstract
Abstract We present theoretical predictions for selected differential cross sections for the process $$pp \rightarrow t {\bar{t}}B$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi><mml:mi>p</mml:mi><mml:mo>→</mml:mo><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:mi>B</mml:mi></mml:mrow></mml:math> at the LHC, where B can be a Higgs ( H ), a Z or a W boson. The predictions are calculated in the direct QCD framework up to the next-to-next-leading logarithmi accuracy and matched to the complete NLO results including QCD and electroweak effects. Additionally, results for the total cross sections are provided. The calculations deliver a significant improvement of the theoretical predictions, especially for the $$ t {\bar{t}}H$$ <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:mi>H</mml:mi></mml:mrow></mml:math> and the $$ t {\bar{t}}Z$$ <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:mi>Z</mml:mi></mml:mrow></mml:math> production. In these cases, predictions for both the total and differential cross sections are remarkably stable with respect to the central scale choice and carry a substantially reduced scale uncertainty in comparison with the complete NLO predictions.