Switch 4-flavor to 5-flavor scheme

[Keping Xie]

I have met a problem when calculating the NLO of DY process under the 5-flavor scheme.
First, I have no model file of sm-no_b_mass to be imported into mg5_amc.
The only one I can do is
> define p = p b b~,
>define j=p,
Then, I make a change to
maxjetflavor=5,
And the parameters
MB=0,
Ymb=0

I generate a simple process
>generate p p > z > e+ e- [QCD],
>output
>launch

I always meet error in this way,
Error detected in "lauch auto"
aMCatNLOError: An error occurred during the collection of results.
In my debug.log file, it shows that the error happens in the file of run_mode : 2.

Does everyone have any idea about how to deal with this question?

[marco zaro (marco-zaro)]

Hi,
I do not fully understand: what happens if you type
import model sm-no_b_mass
or
import model loop_sm-no_b_mass?

to generate drell-yan, try

import model loop_sm-no_b_mass
define p = p b b~
generate p p > e+ e- [QCD]
output

as a general rule, if a quark is massive in the param_card, never set its mass to 0 after the process generation, as this may screw up many things in the cancelation of IR divergencies...

Let me know if this works..
Cheers,

Marco

[Keping Xie (kepingx)]

Hi Marco,
Actually, I have found a similar suggestion as yours.
However, I have no model file of sm_no_b_mass in my MG5_aMC/models directory.
There is a model DY_sm which I can use.
However, this model cannot generate the DY process in the NLO level.

The error report is
Command "generate p p > e+ e- [QCD]" interrupted with error:
InvalidCmd : The model DY_SM cannot handle loop processes

What are the differences of the model files between sm and sm_no_b_mass?

Keping

[marco zaro (marco-zaro)]

Hi Keping,
when you load the model
sm-no_b_mass
you will actually load the model inside the models/sm/ directory
with the restriction from the restrict_no_b_mass.dat card…
Similarly for the loop_sm model…

Does this help you?

Cheers,

Marco

On 14 Jun 2015, at 09:01, Keping Xie <email address hidden> wrote:

> Hi Marco,
> Actually, I have found a similar suggestion as yours.
> However, I have no model file of sm_no_b_mass in my MG5_aMC/models directory.
> There is a model DY_sm which I can use.
> However, this model cannot generate the DY process in the NLO level.
>
> The error report is
> Command "generate p p > e+ e- [QCD]" interrupted with error:
> InvalidCmd : The model DY_SM cannot handle loop processes
>
> What are the differences of the model files between sm and sm_no_b_mass?
>
> Keping
>
> --
> You received this bug notification because you are a bug assignee.
> https://bugs.launchpad.net/bugs/1464971
>
> Title:
> Switch 4-flavor to 5-flavor scheme
>
> Status in MadGraph5_aMC@NLO Generator:
> New
>
> Bug description:
> I have met a problem when calculating the NLO of DY process under the 5-flavor scheme.
> First, I have no model file of sm-no_b_mass to be imported into mg5_amc.
> The only one I can do is
>> define p = p b b~,
>> define j=p,
> Then, I make a change to
> maxjetflavor=5,
> And the parameters
> MB=0,
> Ymb=0
>
> I generate a simple process
>> generate p p > z > e+ e- [QCD],
>> output
>> launch
>
> I always meet error in this way,
> Error detected in "lauch auto"
> aMCatNLOError: An error occurred during the collection of results.
> In my debug.log file, it shows that the error happens in the file of run_mode : 2.
>
> Does everyone have any idea about how to deal with this question?
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/mg5amcnlo/+bug/1464971/+subscriptions

[marco zaro (marco-zaro)]

Hi Keping,
any news on this?
Cheers,

Marco