w+ w- + 0,1,2,3 jets matching

I would advise to have an higher gap between xqcut and qcut it should be at least 10 (sometimes even bigger)

Cheers,

Olivier
> On Oct 25, 2015, at 13:46, lily <email address hidden> wrote:
>
> New question #273034 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/273034
>
> Hi,
> I try to do the matching of w+ w- + 0,1,2,3 jets. Although various values of qcut are set, DJR2 and DJ3 always are not smooth, where the values of 2-jet sample and 3-jet sample are respectively very small. This leads that DJR2 and DJR3 decrease sharply at the cut.
>
> Could you tell me how to set the card?
>
> Some main sets are as follows:
>
> import model sm-no_b_mass
> define j = j b b~
> define p = j
> generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j j, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j j j, w+ > ta+ vt, w- > l- vl~
>
>
> ############################
> run_card.dat:
> ..
> ..
> ..
> # Matching - Warning! ickkw > 1 is still beta
> #*********************************************************************
> 1 = ickkw ! 0 no matching, 1 MLM, 2 CKKW matching
> 1 = highestmult ! for ickkw=2, highest mult group
> 1 = ktscheme ! for ickkw=1, 1 Durham kT, 2 Pythia pTE
> 1 = alpsfact ! scale factor for QCD emission vx
> F = chcluster ! cluster only according to channel diag
> T = pdfwgt ! for ickkw=1, perform pdf reweighting
> 5 = asrwgtflavor ! highest quark flavor for a_s reweight
> T = clusinfo ! include clustering tag in output
> 3.0 = lhe_version ! Change the way clustering information pass to shower.
> #*********************************************************************
> #**********************************************************
> #
> #**********************************************************
> # Automatic ptj and mjj cuts if xqcut > 0
> # (turn off for VBF and single top processes)
> #**********************************************************
> T = auto_ptj_mjj ! Automatic setting of ptj and mjj
> #**********************************************************
> #
> #**********************************
> # BW cutoff (M+/-bwcutoff*Gamma)
> #**********************************
> 15 = bwcutoff ! (M+/-bwcutoff*Gamma)
> #**********************************************************
> # Apply pt/E/eta/dr/mij cuts on decay products or not
> # (note that etmiss/ptll/ptheavy/ht/sorted cuts always apply)
> #**********************************************************
> F = cut_decays ! Cut decay products
> #*************************************************************
> # Number of helicities to sum per event (0 = all helicities)
> # 0 gives more stable result, but longer run time (needed for
> # long decay chains e.g.).
> # Use >=2 if most helicities contribute, e.g. pure QCD.
> #*************************************************************
> 0 = nhel ! Number of helicities used per event
> #*******************
> # Standard Cuts
> #*******************
> #
> #*********************************************************************
> # Minimum and maximum pt's (for max, -1 means no cut) *
> #*********************************************************************
> 15 = ptj ! minimum pt for the jets
> 10 = ptb ! minimum pt for the b
> 10 = pta ! minimum pt for the photons
> 10 = ptl ! minimum pt for the charged leptons
> ..
> ..
> 5 = etaj ! max rap for the jets
> -1 = etab ! max rap for the b
> 2.5 = etaa ! max rap for the photons
> 2.5 = etal ! max rap for the charged leptons
> ..
> ..
> #*********************************************************************
> 5 = maxjetflavor ! Maximum jet pdg code
> #*********************************************************************
> # Jet measure cuts *
> #*********************************************************************
> 15 = xqcut ! minimum kt jet measure between partons
> #*********************************************************************
>
> ################
> Pythia_card.dat:
>
> !...Parton showering on or off
> MSTP(61)=1
> MSTP(71)=1
>
> !...Fragmentation/hadronization on or off
> MSTJ(1)=1
>
> !...Multiple interactions on or off
> MSTP(81)=20
>
> !...Don't stop execution after 10 errors
> MSTU(21)=1
>
> QCUT=20
>
> !...PDFset if MG set not supported by pythia-pgs package (set in lhapdf5 or higher)
> LHAID= 10041
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi Olivier,
Thank you for your reply.

I tried to set
xqcut=10, qcut=20
xqcut=15, qcut=20,30,40,50.
All the results failed.

I take the default value of qcut in the pythia_card.dat, and vary xqcut from 10 to 60 with step=10. All the DJR2 and DJR3 are not smooth.

Best

Do you have the same for w+ w- up to 2j?

I have made some quick check for that process (up to two jet to be able to run quickly on my laptop)
and I do not see any particular problem.

Cheers,

Olivier

> On Oct 25, 2015, at 20:31, lily <email address hidden> wrote:
>
> Question #273034 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/273034
>
> Status: Answered => Open
>
> lily is still having a problem:
> Hi Olivier,
> Thank you for your reply.
>
> I tried to set
> xqcut=10, qcut=20
> xqcut=15, qcut=20,30,40,50.
> All the results failed.
>
> I take the default value of qcut in the pythia_card.dat, and vary xqcut
> from 10 to 60 with step=10. All the DJR2 and DJR3 are not smooth.
>
> Best
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi,

For the w+ w- up to 2j, the problem still appears for the DJR1 and DJR2.

Could you paste your banner.txt here? which versions for your pythia and mg5?

Many thanks.

Hi,

I use MG5 2.3.3 and the pythia via the command install pythia-pgs.

This is the script that I run (not all run where smooth but ok):

import model sm
generate p p > w+ w-
add process p p > w+ w- j
add process p p > w+ w- j j
#add process p p > w+ w- j j j
output
launch
pythia=ON
set use_syst False
set xqcut 20
set qcut 40
launch
set xqcut 30
set qcut 60
launch
set xqcut 50
set qcut 80

Cheers,

Olivier

> On Oct 26, 2015, at 08:42, lily <email address hidden> wrote:
>
> Question #273034 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/273034
>
> Status: Answered => Open
>
> lily is still having a problem:
> Hi,
>
> For the w+ w- up to 2j, the problem still appears for the DJR1 and
> DJR2.
>
> Could you paste your banner.txt here? which versions for your pythia
> and mg5?
>
> Many thanks.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Hi,
Actually, there is no problem for the 4-flavor scheme like your script.

However, the problem will appear for the 5-flavor scheme,

import model sm-no_b_mass
define j = j b b~
define p = j
generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
add process p p > w+ w- j, w+ > ta+ vt, w- > l- vl~
add process p p > w+ w- j j, w+ > ta+ vt, w- > l- vl~
add process p p > w+ w- j j j, w+ > ta+ vt, w- > l- vl~

 5 = maxjetflavor ! Maximum jet pdg code

What is the reason?

Many thanks

Hi,

Did you check if you have diagram where the top can be onshell? decaying in “W b”.
Such on shell contribution should be remove from the matching to avoid double counting with tt~ production.
In top of the double counting this is likely to be the reason of your mismatch.

Cheers,

Olivier

> On Oct 26, 2015, at 14:58, lily <email address hidden> wrote:
>
> Question #273034 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/273034
>
> Status: Answered => Open
>
> lily is still having a problem:
> Hi,
> Actually, there is no problem for the 4-flavor scheme like your script.
>
> However, the problem will appear for the 5-flavor scheme,
>
> import model sm-no_b_mass
> define j = j b b~
> define p = j
> generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j j, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j j j, w+ > ta+ vt, w- > l- vl~
>
> 5 = maxjetflavor ! Maximum jet pdg code
>
> What is the reason?
>
> Many thanks
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Just forget to add that to forbid the top to be on shell (but allowing the off-shell contribution)
you have the following syntax:
>> generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
>> add process p p > w+ w- j, w+ > ta+ vt, w- > l- vl~ $ t t~
>> add process p p > w+ w- j j, w+ > ta+ vt, w- > l- vl~ $ t t~
>> add process p p > w+ w- j j j, w+ > ta+ vt, w- > l- vl~ $ t t~

See https://cp3.irmp.ucl.ac.be/projects/madgraph/attachment/wiki/MGTalks/13_06_10_tutomg_tasi.pdf
for details on this syntax.

Cheers,

Olivier

> On Oct 26, 2015, at 15:16, Olivier Mattelaer <email address hidden> wrote:
>
> Hi,
>
> Did you check if you have diagram where the top can be onshell? decaying in “W b”.
> Such on shell contribution should be remove from the matching to avoid double counting with tt~ production.
> In top of the double counting this is likely to be the reason of your mismatch.
>
> Cheers,
>
> Olivier
>
>
>
>> On Oct 26, 2015, at 14:58, lily <email address hidden> wrote:
>>
>> Question #273034 on MadGraph5_aMC@NLO changed:
>> https://answers.launchpad.net/mg5amcnlo/+question/273034
>>
>> Status: Answered => Open
>>
>> lily is still having a problem:
>> Hi,
>> Actually, there is no problem for the 4-flavor scheme like your script.
>>
>> However, the problem will appear for the 5-flavor scheme,
>>
>> import model sm-no_b_mass
>> define j = j b b~
>> define p = j
>> generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
>> add process p p > w+ w- j, w+ > ta+ vt, w- > l- vl~
>> add process p p > w+ w- j j, w+ > ta+ vt, w- > l- vl~
>> add process p p > w+ w- j j j, w+ > ta+ vt, w- > l- vl~
>>
>> 5 = maxjetflavor ! Maximum jet pdg code
>>
>> What is the reason?
>>
>> Many thanks
>>
>> --
>> You received this question notification because you are an answer
>> contact for MadGraph5_aMC@NLO.
>

Hi Olivier,

>> generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
>> add process p p > w+ w- j, w+ > ta+ vt, w- > l- vl~ $ t t~
>> add process p p > w+ w- j j, w+ > ta+ vt, w- > l- vl~ $ t t~
>> add process p p > w+ w- j j j, w+ > ta+ vt, w- > l- vl~ $ t t~
The above syntax can not solve the problem.

The following syntax may solve the problem:
 generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
 add process p p > w+ w- j $ t t~, w+ > ta+ vt, w- > l- vl~
 add process p p > w+ w- j j $ t t~, w+ > ta+ vt, w- > l- vl~
 add process p p > w+ w- j j j $ t t~, w+ > ta+ vt, w- > l- vl~

In addition, if the signal of w+ > ta+ vt, w- > l- vl, + jets is required to include the b-jet tagging, are there sizable differences between results of the 5-flavor scheme matching and 4-flavor scheme matching? Is the 4-flavor scheme matching correct for the requirement of b-jet tagging?

Many thanks.

Hi,

> The following syntax may solve the problem:

Yes that’s correct.

> In addition, if the signal of w+ > ta+ vt, w- > l- vl, + jets is
> required to include the b-jet tagging, are there sizable differences
> between results of the 5-flavor scheme matching and 4-flavor scheme
> matching? Is the 4-flavor scheme matching correct for the requirement
> of b-jet tagging?

I do not know.
To me, the more natural framework for that is to do a four flavor computation
and asking explicitly b in the final state.
But doing differently is likely to be within theoretical uncertainty (at LO)

Cheers,

Olivier

> On Oct 27, 2015, at 13:32, lily <email address hidden> wrote:
>
> Question #273034 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/273034
>
> Status: Answered => Open
>
> lily is still having a problem:
> Hi Olivier,
>
>>> generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
>>> add process p p > w+ w- j, w+ > ta+ vt, w- > l- vl~ $ t t~
>>> add process p p > w+ w- j j, w+ > ta+ vt, w- > l- vl~ $ t t~
>>> add process p p > w+ w- j j j, w+ > ta+ vt, w- > l- vl~ $ t t~
> The above syntax can not solve the problem.
>
> The following syntax may solve the problem:
> generate p p > w+ w-, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j $ t t~, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j j $ t t~, w+ > ta+ vt, w- > l- vl~
> add process p p > w+ w- j j j $ t t~, w+ > ta+ vt, w- > l- vl~
>
> In addition, if the signal of w+ > ta+ vt, w- > l- vl, + jets is
> required to include the b-jet tagging, are there sizable differences
> between results of the 5-flavor scheme matching and 4-flavor scheme
> matching? Is the 4-flavor scheme matching correct for the requirement
> of b-jet tagging?
>
> Many thanks.
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.