20 | | i.e., variable factorization and renormalization scales,set to the central mT^2 scale after kT-clustering of the event. |

21 | | For a single heavy particle, this corresponds to the M^2+pT^2, |

22 | | for pair of heavy particles it is the geometric mean of M^2+pT^2 for each particle, |

23 | | for massless particles it is the pT^2 of the last pair after clustering. |

24 | | If the last clustering is a t-channel colorless exchange (as, e.g., in WBF), the two fact. scales are set to the last mT^2 values on either side. |

| 20 | i.e., variable factorization and renormalization scales,set to the central mT^2^ scale after kT-clustering of the event. |

| 21 | For a single heavy particle, this corresponds to the M^2^+pT^2^, |

| 22 | for pair of heavy particles it is the geometric mean of M^2^+pT^2^ for each particle, |

| 23 | for massless particles it is the pT^2^ of the last pair after clustering. |

| 24 | If the last clustering is a t-channel colorless exchange (as, e.g., in WBF), the two fact. scales are set to the last mT^2^ values on either side. |

| 25 | |