question on 2.6

Asked by Li on 2018-01-24

Hi,

    Using MG2.6 and I find when I run PYTHIA or Delphs or... when launching, a symbol like "⇐ ̶O̶F̶F̶ ̶" appears, or like "⇐ ̶D̶E̶L̶P̶H̶E̶S̶ ̶", what's the meaning of it?

    And what's the two options for madspin "ON" and "onshell" mean?

Best,
Li

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Li
Solved:
2018-01-31
Last query:
2018-01-31
Last reply:
2018-01-30

This question was reopened

  • 2018-01-30 by Li

Hi Li,

 It means that you asked for OFF but this setup is inconsistent with some other entry that you enter. and therefore if you do enter "enter" (or done or "0") we will not use OFF but the value before it (likely "ON")

In previous versions, the setup was the same but only the first column displayed.
To be precise, the behaviour is actually slightly different in case of very complex setup since in previous version we were actually not keeping the information of what you asked for a given value as we do know. (and that was causing some bad behaviour in previous versions)

Concerning MadSpin=ON and madSpin=onshell.

ON, activate madspin, and allow you to edit the madspin_card.dat (either the one pre-existing or the default one)

if you use
madspin=onshell.
we do the same as for ON, but add in your madspin_card the line "change spinmode onshell"
you can still edit that line if you want to use another mode of madspin
see for more details on madspin: https://cp3.irmp.ucl.ac.be/projects/madgraph/wiki/MadSpin

to be complete that entry also allowed some input that is not proposed in the displayed options:
1 ) madspin=none
which include in the madspin_card.dat the line "change spinmode none"
2) madspin=full
which remove the (first) line "change spinmode" in the card.
3) madspin=madspin
which is an alias to madspin=full

In future, we might allow the user to define special mode for MadSpin that the user can define via a PLUGIN
and in that case, you will be able to put madspin=PLUGIN_NAME
(this option is actually currently used for the reweighting entry)

Cheers,

Olivier

Li (huangli-itp) said : #2

Hi Olivier,

    Thanks a lot for the explanation!

    Other questions are, when I try a model with pp->t1t1->tts1s1->6t, ( process: p p > t1 t1~ , ( t1 > s1 t , s1 > t t~ ) , ( t1~ > s1 t~ , s1 > t t~ )). Here t1 is a top partner and s1 is a scalar. If I write the decay chain in MG5 then use MadSpin, a error raised,

    Command "launch " interrupted with error:
Exception : too much decay at MG level. this can not be done for the moment)

    If I use pp->t1t1 and write the decay in Madspin card,

decay t1 > s1 t, s1 > t t~
decay t1~ > s1 t~, s1 > t t~

    MadSpin works well, but how can I set the branch ratio of t1, s1? Does MadSpin use the decay information from param_card.dat? If I ask MG5 to calculate the decay branch ratio, and write:

decay t1 > s1 t, s1 > all all
decay t1~ > s1 t~, s1 > all all

  in the MadSpin card, can I get the right final states of "s1"?

Best,
Li

Hi,

> Does MadSpin use the decay information from param_card.dat?

Yes it does.
If such information is not present, then MG5aMC calcule them (assuming that the total width does not have three body decay)

Cheers,

Olivier

> On 26 Jan 2018, at 22:37, Li <email address hidden> wrote:
>
> Question #663530 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/663530
>
> Status: Answered => Open
>
> Li is still having a problem:
> Hi Olivier,
>
> Thanks a lot for the explanation!
>
> Other questions are, when I try a model with pp->t1t1->tts1s1->6t, (
> process: p p > t1 t1~ , ( t1 > s1 t , s1 > t t~ ) , ( t1~ > s1 t~ , s1 >
> t t~ )). Here t1 is a top partner and s1 is a scalar. If I write the
> decay chain in MG5 then use MadSpin, a error raised,
>
> Command "launch " interrupted with error:
> Exception : too much decay at MG level. this can not be done for the moment)
>
> If I use pp->t1t1 and write the decay in Madspin card,
>
> decay t1 > s1 t, s1 > t t~
> decay t1~ > s1 t~, s1 > t t~
>
> MadSpin works well, but how can I set the branch ratio of t1, s1?
> Does MadSpin use the decay information from param_card.dat? If I ask MG5
> to calculate the decay branch ratio, and write:
>
> decay t1 > s1 t, s1 > all all
> decay t1~ > s1 t~, s1 > all all
>
> in the MadSpin card, can I get the right final states of "s1"?
>
> Best,
> Li
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Li (huangli-itp) said : #4

Thanks Olivier Mattelaer, that solved my question.

Li (huangli-itp) said : #5

Hi Olivier,

    Sorry for the late reply.

    1) One thing I want to make sure is that the syntax used in MadSpin should be the same in MG5? So that I need to follow the decay chain rule in MG5 like:

decay tp > t z , ( t > w b , w > q q ) , z > q q

    Here the tp is a top partner used as an example.

    2) And I am wondering when I have a "tt" final state and one top goes to hadronic decay while the other one goes to leptonic decay, in MG5 I think I can write:

generate p p > t t~, ( t > w b, w > q q ) , (t ~ > w b, w > l vl)
add process p p > t t~, ( t > w b, w > l vl ) , (t ~ > w b, w >q q)

But how can I do the same thing in the MadSpin? I don't have a preference that top or topbar goes to hadronic decay.

Best,
Li

Hi Li,

We do not have built-in syntax for that.

Cheers,

Olivier

> On 30 Jan 2018, at 06:07, Li <email address hidden> wrote:
>
> Question #663530 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/663530
>
> Status: Solved => Open
>
> Li is still having a problem:
> Hi Olivier,
>
> Sorry for the late reply.
>
> 1) One thing I want to make sure is that the syntax used in MadSpin
> should be the same in MG5? So that I need to follow the decay chain rule
> in MG5 like:
>
> decay tp > t z , ( t > w b , w > q q ) , z > q q
>
> Here the tp is a top partner used as an example.
>
> 2) And I am wondering when I have a "tt" final state and one top
> goes to hadronic decay while the other one goes to leptonic decay, in
> MG5 I think I can write:
>
> generate p p > t t~, ( t > w b, w > q q ) , (t ~ > w b, w > l vl)
> add process p p > t t~, ( t > w b, w > l vl ) , (t ~ > w b, w >q q)
>
> But how can I do the same thing in the MadSpin? I don't have a
> preference that top or topbar goes to hadronic decay.
>
> Best,
> Li
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Li (huangli-itp) said : #7

Hi Olivier,

    Thanks a lot! I will try generate them seperately and merge the files!

Best,
Li