Top (parton level) : Asymmetry : Δy (ttbar)

pythia8~8.226--1sherpa~1.2.3Array
(
    [0] => pythia8
    [1] => 8.226--1sherpa
    [2] => 1.2.3
)
Array
(
    [0] => Array
        (
            [0] => pythia8
            [1] => 8.226--1sherpa
        )

    [1] => Array
        (
            [0] => 1.2.3
        )

)
Array
(
    [pythia8] => Array
        (
            [0] => 8.226--1sherpa
        )

    [1.2.3] => Array
        (
            [0] => 
        )

)