Comment 9 for bug 1805107

By the way, what syntax should I use to check the interference diagrams? I
am kind of lost with this. Thanks very much!

Pablo

El mar., 11 dic. 2018 a las 10:21, Pablo Martín (<email address hidden>)
escribió:

> The decay chain still assumes that all other contribution (in particular
>> interference term) are negligible compare to the selected contribution.
>> This is far to be automatic with large width.
>> And this is something that you should check at least once.
>>
>
> I will! Thanks Olivier!
>
>
> El lun., 10 dic. 2018 a las 17:21, Olivier Mattelaer (<
> <email address hidden>>) escribió:
>
>> Hi,
>>
>> The decay chain still assumes that all other contribution (in particular
>> interference term) are negligible compare to the selected contribution.
>> This is far to be automatic with large width.
>> And this is something that you should check at least once.
>>
>> >just by curiosity, how is the cross section computed by using this
>> method?
>>
>> We integrate over the full matrix-element whith a normal propagator for
>> your particle.
>> (we just have custom bound to select the "onshell" contribution (define
>> up to 15 times the width)
>>
>> Cheers,
>>
>> Olivier
>>
>> --
>> You received this bug notification because you are subscribed to the bug
>> report.
>> https://bugs.launchpad.net/bugs/1805107
>>
>> Title:
>> Madspin fails to decay events for large couplings
>>
>> Status in MadGraph5_aMC@NLO:
>> New
>>
>> Bug description:
>> Hi Olivier,
>>
>> I am running a LO event generation with decays through Madspin. I
>> implemented my model in Feynrules, and I basically have SM + new
>> scalar doublet with slepton quantum numbers + new fermion singlet
>> under SM. You helped me with a tricky bug in "#1801760 Madspin fails
>> with majorana particle" a couple of weeks ago, so you might remember
>> the model.
>>
>> I found another issue. When Madspin decays the events, I am getting
>> the following warning for some of them:
>>
>> INFO: All production process does not have the same total Branching
>> Ratio.
>> Therefore the total number of events after decay
>> will be lower than the original file.
>> [max_br = 0.99515608014, min_br = 0.992471423458]
>>
>> which is not too bad, but if the coupling for the relevant vertex
>> (phil-psi-lepton) is too large (~3), Madspin gets stuck decaying the
>> events:
>>
>> ...
>> ...
>> INFO: Event 291/300 : 2.8s
>> INFO: Event 296/300 : 2.8s
>> INFO: All production process does not have the same total Branching
>> Ratio.
>> Therefore the total number of events after decay
>> will be lower than the original file.
>> [max_br = 0.99515608014, min_br = 0.992471423458]
>> INFO:
>> INFO: Decaying the events...
>>
>>
>> Any clues about this one? Thanks!
>>
>> Cheers,
>>
>> Pablo
>>
>> To manage notifications about this bug go to:
>> https://bugs.launchpad.net/mg5amcnlo/+bug/1805107/+subscriptions
>>
>