MadGraph5_aMC@NLO

Strange values of U and D mass in pythia.cmd

Asked by Andrew McAdams

Hi! I am using mg5_amc@NLO to simulate the production of B mesons (generate p p > b b~ [QCD]). In the card pythia.cmd which is generated dynamically I found the following two strings:
DMASS=0.33
UMASS=0.33

They look weird. Could you please explain what is the reason for setting these values to be so large?

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MadGraph5_aMC@NLO Edit question
Assignee:
Paolo Torrielli Edit question
Solved by:
Paolo Torrielli
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Best Paolo Torrielli (paolotorriell) said : 		#1

Dear Andrew,

I guess these should be thought as effective mass parameters entering
the computation of hadron masses, not quite as the pole quark masses.

Since this is a MonteCarlo-specific choice (for instance Herwig6 uses a
non-zero gluon mass), I think it is better if you find some more detailed
information in the Pythia6 manual hep-ph/0603175, chapter 13.2.1.
I just point out that there is no MG5 intervention on those particular
mass values.

Best.
Paolo

Revision history for this message
Andrew McAdams (mcadams1994) said : 		#2

Thanks Paolo Torrielli, that solved my question.