Inconsistent cross section between two processes

Hi,

Like this impossible to tell you.

What is the b mass value?
What is the definition of p/j? Do they contain the b?
What is the value of maxjetflavor?

In top of that: is this a typo?
> add process g b > x x~ b @1
in this case you do not forbid the top?

Cheers,

Olivier

On 10 Mar 2015, at 11:22, guy pitman <email address hidden> wrote:

> New question #263443 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/263443
>
> I am trying to simulate a model generating dark matter particles using a Lagrangian in Feynrules coupling dark matter fermions to quarks O =(mq/M^3) q q~ x x~. (x = dm fermion)
>
> Can you please explain why the cross section calculated using the following processes
>
> generate p p > x x~ j /t @0
> add process p p > x x~ j j /t @1
>
> is about 4 Pb after matching (with matching efficiency of about .28)
>
> whereas generate p p > x x~ b j / t @0
> add process g b > x x~ b @1
>
> is about 23.25 Pb with (matching efficiency of .9999).
>
> ie specifying a subset of the end process results in a much higher cross section and matching efficiency?
>
> All other parameters are the same.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier

Sorry- I have taken the default b mass value (47 I think)
p is the proton. j had maxjetflavor= 4, and I didnt exclude the top from g b >x x~ b

However I have now changed j to maxjet flavor=5 in both simulations and add process g b > x x~ b /t for consistency
Now I have

generate p p > x x~ j /t @0
add process p p > x x~ j j /t @1

is about 4 Pb after matching (with matching efficiency of .28)

generate p p > x x~ b j / t @0
add process g b > x x~ b /t @1

has cross section of 5.28 (with matching efficiency of .41)

Second set of processes still have a higher cross section even though a subset of the first?
Is this correct?
Thanks
Guy

Further to my last question, I have noticed that the pythia log files have the following at the end - does this help?

Thank you again

 Error type 9 has occured after 79 PYEXEC calls:
     (PYPTIS:) Weight 3.5271E+00 above unity

 KTWARN CALLED FROM SUBPROGRAM KTRECO: CODE = 101

 WARNING: Tau doesn't come from W/Z/H.

 KTWARN CALLED FROM SUBPROGRAM KTRECO: CODE = 101

 WARNING: Tau doesn't come from W/Z/H.
 WARNING: Tau doesn't come from W/Z/H.
 WARNING: Tau doesn't come from W/Z/H.
 WARNING: Tau doesn't come from W/Z/H.
 WARNING: Tau doesn't come from W/Z/H.
 WARNING: Tau doesn't come from W/Z/H.

     Error type 9 has occured after 1804 PYEXEC calls:
     (PYPTIS:) Weight 1.8867E+03 above unity
 WARNING: Tau doesn't come from W/Z/H.

 KTWARN CALLED FROM SUBPROGRAM KTRECO: CODE = 101

     Advisory warning type 9 given after 2733 PYEXEC calls:
     (PYPTIS:) Weight 1.2214E+02 above unity
  Failed to read LHEF event information,
  assume end of file has been reached.

Hi Guy,

The question is what is the particle content of the proton?
Does it contains b or not?

if you do not know then the default is that the b is not part of the proton (as consistent in the 4 flavor scheme).

Cheers,

Olivier

Hi Olivier,

I have maxjetfavor=5 ("However I have now changed j to maxjet flavor=5 in both simulations") so that implies that b is part of the proton?

My main question now is what has caused :
Error type 9 has occured after 79 PYEXEC calls:
     (PYPTIS:) Weight 3.5271E+00 above unity

etc

Thank you
Regards
Guy

Thanks Olivier Mattelaer, that solved my question.