MadGraph5_aMC@NLO

slepton decay chain

Asked by Kristian

Hey everyone,

I am trying to implement the following processes:

a a > mur+ mur-, mur- > mu- n1, mur+ > mu+ n1
a a > er+ er-, er- > e- n1, er+ > e+ n1

The processes run well, but there seems to be something off with the cross-sections. If I run only the first parts

a a > mur+ mur-
a a > er+ er-

I get consistently larger cross-sections than from the whole procedure, even though the branching ratios of (mur+-/er+- > mu+-/e+- n1) have been defined as 1 in param_card.dat. Somehow it still looks like we are losing some particles in decay process.

This relation between the cross-sections is independent of the masses used and the difference is about 10%.

Is there by any chance some kind of normalization parameters I have missed, or is it possible that not all sleptons decay? Is it possible, that there are some modes I am excluding for some reason?

Thank you in advance,

Kristian

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Did you look at the following FAQ?
Also note that we do not use the BR information in the param_card. We only use the total width (and the mass/couplings/...)

FAQ #2442: “why production and decay cross-section didn't agree.”.

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