MadGraph5_aMC@NLO

SPINUP variable in aMC@NLO's LHEF

Asked by Wojciech Kotlarski

Dear MG/aMC@NLO authors,

When running MG in the NLO mode, particles in events do not have assigned spins. The SPINUP variable in LHEF is set to 0. I'm not using MadSpin so this is not related to question 240938: Spin information from MadSpin. Is this behaviour intended?

cheers,
Wojciech

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
marco zaro Edit question
Solved by:
Rikkert Frederix
Solved:
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Last reply:
Revision history for this message
Rikkert Frederix (frederix) said : 		#1

Dear Wojciech,

Yes, this is intended. At NLO the spin-information is not available.

Kind regards,
Rikkert

Revision history for this message
Wojciech Kotlarski (wojciech-kotlarski) said : 		#2

Dear Rikkert,

Thank you for your answer. I'm just surprised, because when you look into the paper on MadSpin there are plots of spin effects @NLO for ttbarH (http://arxiv.org/pdf/1212.3460v2.pdf). Is this just not implemented yet?

regards,
Wojciech

Revision history for this message
Best Rikkert Frederix (frederix) said : 		#3

Dear Wojciech,

Indeed, if you use MadSpin the spin information is reconstructed as is explained in that paper. This is completely independent from writing the spin-information in the LHE file for undecayed top quarks.

Kind regards,
Rikkert

Revision history for this message
Wojciech Kotlarski (wojciech-kotlarski) said : 		#4

Thanks Rikkert Frederix, that solved my question.