=== What are the default dynamic factorization and renormalization scales in !MadEvent? ===

Since v.4.2.17, there is a new default dynamical scale choice in run_card.dat file: 

{{{
#*********************************************************************
# Renormalization and factorization scales                           *
#*********************************************************************
 F        = fixed_ren_scale  ! if .true. use fixed ren scale
 F        = fixed_fac_scale  ! if .true. use fixed fac scale
 91.1880  = scale            ! fixed ren scale
 91.1880  = dsqrt_q2fact1    ! fixed fact scale for pdf1
 91.1880  = dsqrt_q2fact2    ! fixed fact scale for pdf2
 1        = scalefact        ! scale factor for event-by-event scales
}}}


i.e., variable factorization and renormalization scales,set to the central mT^2^ scale after kT-clustering of the event.
For a single heavy particle, this corresponds to the M^2^+pT^2^, 
for pair of heavy particles it is the geometric mean of M^2^+pT^2^ for each particle, 
for massless particles it is the pT^2^ of the last pair after clustering. 
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. 

These scales are overridden by scales defined in [http://bazaar.launchpad.net/~madteam/madgraph5/trunk/view/head:/Template/SubProcesses/setscales.f setscales.f], if they are returned as non-0.

See [wiki:FAQ-General-2 How do I implement my own renormalization/factorization scales in MadEvent ?] for information about how to implement your own scales in MadEvent.