ratio of cross section (p p~ > z c) / (p p~ > z b)

Hi,

This is a very detailed question which is impossible for us to answer without making a full analysis on such ratio. But this is the reflexion that I have on your approach.

1) Why do you use a five flavour matching (all b/c jet are massless and indistinguishable) for such comparison, Should not you use a three/four flavour matching?
and therefore have not b/c present in the pdf?
2) Should not you use a matched/merged generation for such type of computation? This is particularly important for you pt cut.
3) Due to you pt_j cut, I do not expect that the computation in MG and PY matches, since it is likely that the pt cut applied not on the 2 > 2 particles but on the QCD radiation associated to the events.
In other word you need to simulate the shower (and in preference in a matched/merged generation)

Cheers,

Olivier

On 29 Aug 2015, at 18:31, miranda <email address hidden> wrote:

> New question #270897 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/270897
>
> Dear Authors
> I am trying to compute the ratio of cross section (p p~ > z c) / (p p~ > z b) to comparison with measurement was carried out by D0 (arXiv:1308.4384).
> But I got into trouble with this project and tried different ways to solve it, but my efforts failed.
> As a last resort I decided to ask you to help me.
> Could you please guide me to solve it?
> define p = p b b~
> define j = j b b~
> generate p p > z c for p p~ > z c
> generate p p > z b for p p~ > z b
>
> then I divide the results of the cross section (z c and z b) for PT (j_1) available in HTML folder.
> when I compared my results with the results of that paper, I found that my results are different while I set
> the same cut as that paper’s.
> I don’t expect that my results reach the data, but I expect they will be close to Pythia.
> I sent you the runcard that we used.
> Please let me know your idea about this.
> I look forward hearing from you.
> Thank you in advance
>
> #*********************************************************************
> # MadGraph5_aMC@NLO *
> # *
> # run_card.dat MadEvent *
> # *
> # This file is used to set the parameters of the run. *
> # *
> # Some notation/conventions: *
> # *
> # Lines starting with a '# ' are info or comments *
> # *
> # mind the format: value = variable ! comment *
> #*********************************************************************
> #
> #*******************
> # Running parameters
> #*******************
> #
> #*********************************************************************
> # Tag name for the run (one word) *
> #*********************************************************************
> tag_1 = run_tag ! name of the run
> #*********************************************************************
> # Run to generate the grid pack *
> #*********************************************************************
> False = gridpack !True = setting up the grid pack
> #*********************************************************************
> # Number of events and rnd seed *
> # Warning: Do not generate more than 1M events in a single run *
> # If you want to run Pythia, avoid more than 50k events in a run. *
> #*********************************************************************
> 10000 = nevents ! Number of unweighted events requested
> 0 = iseed ! rnd seed (0=assigned automatically=default))
> #*********************************************************************
> # Collider type and energy *
> # lpp: 0=No PDF, 1=proton, -1=antiproton, 2=photon from proton, *
> # 3=photon from electron *
> #*********************************************************************
> 1 = lpp1 ! beam 1 type
> -1 = lpp2 ! beam 2 type
> 980.0 = ebeam1 ! beam 1 total energy in GeV
> 980.0 = ebeam2 ! beam 2 total energy in GeV
> #*********************************************************************
> # Beam polarization from -100 (left-handed) to 100 (right-handed) *
> #*********************************************************************
> 0.0 = polbeam1 ! beam polarization for beam 1
> 0.0 = polbeam2 ! beam polarization for beam 2
> #*********************************************************************
> # PDF CHOICE: this automatically fixes also alpha_s and its evol. *
> #*********************************************************************
> 'cteq6l1' = pdlabel ! PDF set (lhapdf for using lhapdf)
> 10042 = lhaid ! PDF number used ONLY for LHAPDF
> #*********************************************************************
> # Renormalization and factorization scales *
> #*********************************************************************
> False = fixed_ren_scale ! if .true. use fixed ren scale
> False = fixed_fac_scale ! if .true. use fixed fac scale
> 91.188 = scale ! fixed ren scale
> 91.188 = dsqrt_q2fact1 ! fixed fact scale for pdf1
> 91.188 = dsqrt_q2fact2 ! fixed fact scale for pdf2
> -1 = dynamical_scale_choice ! Select one of the preselect dynamical choice
> 1.0 = scalefact ! scale factor for event-by-event scales
> #*********************************************************************
> # Time of flight information. (-1 means not run)
> #*********************************************************************
> -1.0 = time_of_flight ! threshold below which info is not written
> #*********************************************************************
> # Matching - Warning! ickkw > 1 is still beta
> #*********************************************************************
> 0 = 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
> False = chcluster ! cluster only according to channel diag
> True = pdfwgt ! for ickkw=1, perform pdf reweighting
> 5 = asrwgtflavor ! highest quark flavor for a_s reweight
> True = 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)
> #**********************************************************
> True = auto_ptj_mjj ! Automatic setting of ptj and mjj
> #**********************************************************
> #
> #**********************************
> # BW cutoff (M+/-bwcutoff*Gamma)
> #**********************************
> 15.0 = 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)
> #**********************************************************
> False = 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) *
> #*********************************************************************
> 20.0 = ptj ! minimum pt for the jets
> 0.0 = ptb ! minimum pt for the b
> 0.0 = pta ! minimum pt for the photons
> 0.0 = ptl ! minimum pt for the charged leptons
> 0.0 = misset ! minimum missing Et (sum of neutrino's momenta)
> 0.0 = ptheavy ! minimum pt for one heavy final state
> -1.0 = ptjmax ! maximum pt for the jets
> -1.0 = ptbmax ! maximum pt for the b
> -1.0 = ptamax ! maximum pt for the photons
> -1.0 = ptlmax ! maximum pt for the charged leptons
> -1.0 = missetmax ! maximum missing Et (sum of neutrino's momenta)
> #*********************************************************************
> # Minimum and maximum E's (in the center of mass frame) *
> #*********************************************************************
> 0.0 = ej ! minimum E for the jets
> 0.0 = eb ! minimum E for the b
> 0.0 = ea ! minimum E for the photons
> 0.0 = el ! minimum E for the charged leptons
> -1.0 = ejmax ! maximum E for the jets
> -1.0 = ebmax ! maximum E for the b
> -1.0 = eamax ! maximum E for the photons
> -1.0 = elmax ! maximum E for the charged leptons
> #*********************************************************************
> # Maximum and minimum absolute rapidity (for max, -1 means no cut) *
> #*********************************************************************
> 2.5 = etaj ! max rap for the jets
> -1.0 = etab ! max rap for the b
> -1.0 = etaa ! max rap for the photons
> -1.0 = etal ! max rap for the charged leptons
> 0.0 = etajmin ! min rap for the jets
> 0.0 = etabmin ! min rap for the b
> 0.0 = etaamin ! min rap for the photons
> 0.0 = etalmin ! main rap for the charged leptons
> #*********************************************************************
> # Minimum and maximum DeltaR distance *
> #*********************************************************************
> 0.0 = drjj ! min distance between jets
> 0.0 = drbb ! min distance between b's
> 0.0 = drll ! min distance between leptons
> 0.0 = draa ! min distance between gammas
> 0.0 = drbj ! min distance between b and jet
> 0.0 = draj ! min distance between gamma and jet
> 0.0 = drjl ! min distance between jet and lepton
> 0.0 = drab ! min distance between gamma and b
> 0.0 = drbl ! min distance between b and lepton
> 0.0 = dral ! min distance between gamma and lepton
> -1.0 = drjjmax ! max distance between jets
> -1.0 = drbbmax ! max distance between b's
> -1.0 = drllmax ! max distance between leptons
> -1.0 = draamax ! max distance between gammas
> -1.0 = drbjmax ! max distance between b and jet
> -1.0 = drajmax ! max distance between gamma and jet
> -1.0 = drjlmax ! max distance between jet and lepton
> -1.0 = drabmax ! max distance between gamma and b
> -1.0 = drblmax ! max distance between b and lepton
> -1.0 = dralmax ! maxdistance between gamma and lepton
> #*********************************************************************
> # Minimum and maximum invariant mass for pairs *
> # WARNING: for four lepton final state mmll cut require to have *
> # different lepton masses for each flavor! *
> #*********************************************************************
> 0.0 = mmjj ! min invariant mass of a jet pair
> 0.0 = mmbb ! min invariant mass of a b pair
> 0.0 = mmaa ! min invariant mass of gamma gamma pair
> 0.0 = mmll ! min invariant mass of l+l- (same flavour) lepton pair
> -1.0 = mmjjmax ! max invariant mass of a jet pair
> -1.0 = mmbbmax ! max invariant mass of a b pair
> -1.0 = mmaamax ! max invariant mass of gamma gamma pair
> -1.0 = mmllmax ! max invariant mass of l+l- (same flavour) lepton pair
> #*********************************************************************
> # Minimum and maximum invariant mass for all letpons *
> #*********************************************************************
> 0.0 = mmnl ! min invariant mass for all letpons (l+- and vl)
> -1.0 = mmnlmax ! max invariant mass for all letpons (l+- and vl)
> #*********************************************************************
> # Minimum and maximum pt for 4-momenta sum of leptons *
> #*********************************************************************
> 0.0 = ptllmin ! Minimum pt for 4-momenta sum of leptons(l and vl)
> -1.0 = ptllmax ! Maximum pt for 4-momenta sum of leptons(l and vl)
> #*********************************************************************
> # Inclusive cuts *
> #*********************************************************************
> 0.0 = xptj ! minimum pt for at least one jet
> 0.0 = xptb ! minimum pt for at least one b
> 0.0 = xpta ! minimum pt for at least one photon
> 0.0 = xptl ! minimum pt for at least one charged lepton
> #*********************************************************************
> # Control the pt's of the jets sorted by pt *
> #*********************************************************************
> 0.0 = ptj1min ! minimum pt for the leading jet in pt
> 0.0 = ptj2min ! minimum pt for the second jet in pt
> 0.0 = ptj3min ! minimum pt for the third jet in pt
> 0.0 = ptj4min ! minimum pt for the fourth jet in pt
> -1.0 = ptj1max ! maximum pt for the leading jet in pt
> -1.0 = ptj2max ! maximum pt for the second jet in pt
> -1.0 = ptj3max ! maximum pt for the third jet in pt
> -1.0 = ptj4max ! maximum pt for the fourth jet in pt
> 0 = cutuse ! reject event if fails any (0) / all (1) jet pt cuts
> #*********************************************************************
> # Control the pt's of leptons sorted by pt *
> #*********************************************************************
> 0.0 = ptl1min ! minimum pt for the leading lepton in pt
> 0.0 = ptl2min ! minimum pt for the second lepton in pt
> 0.0 = ptl3min ! minimum pt for the third lepton in pt
> 0.0 = ptl4min ! minimum pt for the fourth lepton in pt
> -1.0 = ptl1max ! maximum pt for the leading lepton in pt
> -1.0 = ptl2max ! maximum pt for the second lepton in pt
> -1.0 = ptl3max ! maximum pt for the third lepton in pt
> -1.0 = ptl4max ! maximum pt for the fourth lepton in pt
> #*********************************************************************
> # Control the Ht(k)=Sum of k leading jets *
> #*********************************************************************
> 0.0 = htjmin ! minimum jet HT=Sum(jet pt)
> -1.0 = htjmax ! maximum jet HT=Sum(jet pt)
> 0.0 = ihtmin !inclusive Ht for all partons (including b)
> -1.0 = ihtmax !inclusive Ht for all partons (including b)
> 0.0 = ht2min ! minimum Ht for the two leading jets
> 0.0 = ht3min ! minimum Ht for the three leading jets
> 0.0 = ht4min ! minimum Ht for the four leading jets
> -1.0 = ht2max ! maximum Ht for the two leading jets
> -1.0 = ht3max ! maximum Ht for the three leading jets
> -1.0 = ht4max ! maximum Ht for the four leading jets
> #***********************************************************************
> # Photon-isolation cuts, according to hep-ph/9801442 *
> # When ptgmin=0, all the other parameters are ignored *
> # When ptgmin>0, pta and draj are not going to be used *
> #***********************************************************************
> 0.0 = ptgmin ! Min photon transverse momentum
> 0.4 = R0gamma ! Radius of isolation code
> 1.0 = xn ! n parameter of eq.(3.4) in hep-ph/9801442
> 1.0 = epsgamma ! epsilon_gamma parameter of eq.(3.4) in hep-ph/9801442
> True = isoEM ! isolate photons from EM energy (photons and leptons)
> #*********************************************************************
> # WBF cuts *
> #*********************************************************************
> 0.0 = xetamin ! minimum rapidity for two jets in the WBF case
> 0.0 = deltaeta ! minimum rapidity for two jets in the WBF case
> #*********************************************************************
> # KT DURHAM CUT *
> #*********************************************************************
> -1.0 = ktdurham
> 0.4 = dparameter
> #*********************************************************************
> # maximal pdg code for quark to be considered as a light jet *
> # (otherwise b cuts are applied) *
> #*********************************************************************
> 5 = maxjetflavor ! Maximum jet pdg code
> #*********************************************************************
> # Jet measure cuts *
> #*********************************************************************
> 0.0 = xqcut ! minimum kt jet measure between partons
> #*********************************************************************
> #
> #*********************************************************************
> # Store info for systematics studies *
> # WARNING: If use_syst is T, matched Pythia output is *
> # meaningful ONLY if plotted taking matchscale *
> # reweighting into account! *
> #*********************************************************************
> True = use_syst ! Enable systematics studies
> #
> #**************************************
> # Parameter of the systematics study
> # will be used by SysCalc (if installed)
> #**************************************
> #
> 0.5 1 2 = sys_scalefact # factorization/renormalization scale factor
> 0.5 1 2 = sys_alpsfact # \alpha_s emission scale factors
> 30 50 = sys_matchscale # variation of merging scale
> # PDF sets and number of members (0 or none for all members).
> Ct10nlo.LHgrid = sys_pdf # matching scales
> # MSTW2008nlo68cl.LHgrid 1 = sys_pdf
>
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Dear Dr Olivier Mattelaer

Thank you for your response. I really appreciate your advice.

Could you please guide me again?

About parton shower, is it enough to run the pythia shower: pythia=ON

and run with MLM matching (the options ickkw=1 in the run_card.dat)

Or I have to change "xqcut" and other options?

Best Regards
Miranda

On Sun, Aug 30, 2015 at 1:16 AM, Olivier Mattelaer <
<email address hidden>> wrote:

> Your question #270897 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/270897
>
> Status: Open => Answered
>
> Olivier Mattelaer proposed the following answer:
> Hi,
>
> This is a very detailed question which is impossible for us to answer
> without making a full analysis on such ratio. But this is the reflexion
> that I have on your approach.
>
> 1) Why do you use a five flavour matching (all b/c jet are massless and
> indistinguishable) for such comparison, Should not you use a three/four
> flavour matching?
> and therefore have not b/c present in the pdf?
> 2) Should not you use a matched/merged generation for such type of
> computation? This is particularly important for you pt cut.
> 3) Due to you pt_j cut, I do not expect that the computation in MG and PY
> matches, since it is likely that the pt cut applied not on the 2 > 2
> particles but on the QCD radiation associated to the events.
> In other word you need to simulate the shower (and in preference in a
> matched/merged generation)
>
> Cheers,
>
> Olivier
>
>
> On 29 Aug 2015, at 18:31, miranda <email address hidden>
> wrote:
>
> > New question #270897 on MadGraph5_aMC@NLO:
> > https://answers.launchpad.net/mg5amcnlo/+question/270897
> >
> > Dear Authors
> > I am trying to compute the ratio of cross section (p p~ > z c) / (p p~ >
> z b) to comparison with measurement was carried out by D0 (arXiv:1308.4384).
> > But I got into trouble with this project and tried different ways to
> solve it, but my efforts failed.
> > As a last resort I decided to ask you to help me.
> > Could you please guide me to solve it?
> > define p = p b b~
> > define j = j b b~
> > generate p p > z c for p p~ > z c
> > generate p p > z b for p p~ > z b
> >
> > then I divide the results of the cross section (z c and z b) for PT
> (j_1) available in HTML folder.
> > when I compared my results with the results of that paper, I found that
> my results are different while I set
> > the same cut as that paper’s.
> > I don’t expect that my results reach the data, but I expect they will be
> close to Pythia.
> > I sent you the runcard that we used.
> > Please let me know your idea about this.
> > I look forward hearing from you.
> > Thank you in advance
> >
> > #*********************************************************************
> > # MadGraph5_aMC@NLO *
> > # *
> > # run_card.dat MadEvent *
> > # *
> > # This file is used to set the parameters of the run. *
> > # *
> > # Some notation/conventions: *
> > # *
> > # Lines starting with a '# ' are info or comments *
> > # *
> > # mind the format: value = variable ! comment *
> > #*********************************************************************
> > #
> > #*******************
> > # Running parameters
> > #*******************
> > #
> > #*********************************************************************
> > # Tag name for the run (one word) *
> > #*********************************************************************
> > tag_1 = run_tag ! name of the run
> > #*********************************************************************
> > # Run to generate the grid pack *
> > #*********************************************************************
> > False = gridpack !True = setting up the grid pack
> > #*********************************************************************
> > # Number of events and rnd seed *
> > # Warning: Do not generate more than 1M events in a single run *
> > # If you want to run Pythia, avoid more than 50k events in a run. *
> > #*********************************************************************
> > 10000 = nevents ! Number of unweighted events requested
> > 0 = iseed ! rnd seed (0=assigned automatically=default))
> > #*********************************************************************
> > # Collider type and energy *
> > # lpp: 0=No PDF, 1=proton, -1=antiproton, 2=photon from proton, *
> > # 3=photon from electron *
> > #*********************************************************************
> > 1 = lpp1 ! beam 1 type
> > -1 = lpp2 ! beam 2 type
> > 980.0 = ebeam1 ! beam 1 total energy in GeV
> > 980.0 = ebeam2 ! beam 2 total energy in GeV
> > #*********************************************************************
> > # Beam polarization from -100 (left-handed) to 100 (right-handed) *
> > #*********************************************************************
> > 0.0 = polbeam1 ! beam polarization for beam 1
> > 0.0 = polbeam2 ! beam polarization for beam 2
> > #*********************************************************************
> > # PDF CHOICE: this automatically fixes also alpha_s and its evol. *
> > #*********************************************************************
> > 'cteq6l1' = pdlabel ! PDF set (lhapdf for using lhapdf)
> > 10042 = lhaid ! PDF number used ONLY for LHAPDF
> > #*********************************************************************
> > # Renormalization and factorization scales *
> > #*********************************************************************
> > False = fixed_ren_scale ! if .true. use fixed ren scale
> > False = fixed_fac_scale ! if .true. use fixed fac scale
> > 91.188 = scale ! fixed ren scale
> > 91.188 = dsqrt_q2fact1 ! fixed fact scale for pdf1
> > 91.188 = dsqrt_q2fact2 ! fixed fact scale for pdf2
> > -1 = dynamical_scale_choice ! Select one of the preselect dynamical
> choice
> > 1.0 = scalefact ! scale factor for event-by-event scales
> > #*********************************************************************
> > # Time of flight information. (-1 means not run)
> > #*********************************************************************
> > -1.0 = time_of_flight ! threshold below which info is not written
> > #*********************************************************************
> > # Matching - Warning! ickkw > 1 is still beta
> > #*********************************************************************
> > 0 = 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
> > False = chcluster ! cluster only according to channel diag
> > True = pdfwgt ! for ickkw=1, perform pdf reweighting
> > 5 = asrwgtflavor ! highest quark flavor for a_s reweight
> > True = 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)
> > #**********************************************************
> > True = auto_ptj_mjj ! Automatic setting of ptj and mjj
> > #**********************************************************
> > #
> > #**********************************
> > # BW cutoff (M+/-bwcutoff*Gamma)
> > #**********************************
> > 15.0 = 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)
> > #**********************************************************
> > False = 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) *
> > #*********************************************************************
> > 20.0 = ptj ! minimum pt for the jets
> > 0.0 = ptb ! minimum pt for the b
> > 0.0 = pta ! minimum pt for the photons
> > 0.0 = ptl ! minimum pt for the charged leptons
> > 0.0 = misset ! minimum missing Et (sum of neutrino's momenta)
> > 0.0 = ptheavy ! minimum pt for one heavy final state
> > -1.0 = ptjmax ! maximum pt for the jets
> > -1.0 = ptbmax ! maximum pt for the b
> > -1.0 = ptamax ! maximum pt for the photons
> > -1.0 = ptlmax ! maximum pt for the charged leptons
> > -1.0 = missetmax ! maximum missing Et (sum of neutrino's momenta)
> > #*********************************************************************
> > # Minimum and maximum E's (in the center of mass frame) *
> > #*********************************************************************
> > 0.0 = ej ! minimum E for the jets
> > 0.0 = eb ! minimum E for the b
> > 0.0 = ea ! minimum E for the photons
> > 0.0 = el ! minimum E for the charged leptons
> > -1.0 = ejmax ! maximum E for the jets
> > -1.0 = ebmax ! maximum E for the b
> > -1.0 = eamax ! maximum E for the photons
> > -1.0 = elmax ! maximum E for the charged leptons
> > #*********************************************************************
> > # Maximum and minimum absolute rapidity (for max, -1 means no cut) *
> > #*********************************************************************
> > 2.5 = etaj ! max rap for the jets
> > -1.0 = etab ! max rap for the b
> > -1.0 = etaa ! max rap for the photons
> > -1.0 = etal ! max rap for the charged leptons
> > 0.0 = etajmin ! min rap for the jets
> > 0.0 = etabmin ! min rap for the b
> > 0.0 = etaamin ! min rap for the photons
> > 0.0 = etalmin ! main rap for the charged leptons
> > #*********************************************************************
> > # Minimum and maximum DeltaR distance *
> > #*********************************************************************
> > 0.0 = drjj ! min distance between jets
> > 0.0 = drbb ! min distance between b's
> > 0.0 = drll ! min distance between leptons
> > 0.0 = draa ! min distance between gammas
> > 0.0 = drbj ! min distance between b and jet
> > 0.0 = draj ! min distance between gamma and jet
> > 0.0 = drjl ! min distance between jet and lepton
> > 0.0 = drab ! min distance between gamma and b
> > 0.0 = drbl ! min distance between b and lepton
> > 0.0 = dral ! min distance between gamma and lepton
> > -1.0 = drjjmax ! max distance between jets
> > -1.0 = drbbmax ! max distance between b's
> > -1.0 = drllmax ! max distance between leptons
> > -1.0 = draamax ! max distance between gammas
> > -1.0 = drbjmax ! max distance between b and jet
> > -1.0 = drajmax ! max distance between gamma and jet
> > -1.0 = drjlmax ! max distance between jet and lepton
> > -1.0 = drabmax ! max distance between gamma and b
> > -1.0 = drblmax ! max distance between b and lepton
> > -1.0 = dralmax ! maxdistance between gamma and lepton
> > #*********************************************************************
> > # Minimum and maximum invariant mass for pairs *
> > # WARNING: for four lepton final state mmll cut require to have *
> > # different lepton masses for each flavor! *
> > #*********************************************************************
> > 0.0 = mmjj ! min invariant mass of a jet pair
> > 0.0 = mmbb ! min invariant mass of a b pair
> > 0.0 = mmaa ! min invariant mass of gamma gamma pair
> > 0.0 = mmll ! min invariant mass of l+l- (same flavour) lepton pair
> > -1.0 = mmjjmax ! max invariant mass of a jet pair
> > -1.0 = mmbbmax ! max invariant mass of a b pair
> > -1.0 = mmaamax ! max invariant mass of gamma gamma pair
> > -1.0 = mmllmax ! max invariant mass of l+l- (same flavour) lepton pair
> > #*********************************************************************
> > # Minimum and maximum invariant mass for all letpons *
> > #*********************************************************************
> > 0.0 = mmnl ! min invariant mass for all letpons (l+- and vl)
> > -1.0 = mmnlmax ! max invariant mass for all letpons (l+- and vl)
> > #*********************************************************************
> > # Minimum and maximum pt for 4-momenta sum of leptons *
> > #*********************************************************************
> > 0.0 = ptllmin ! Minimum pt for 4-momenta sum of leptons(l and vl)
> > -1.0 = ptllmax ! Maximum pt for 4-momenta sum of leptons(l and vl)
> > #*********************************************************************
> > # Inclusive cuts *
> > #*********************************************************************
> > 0.0 = xptj ! minimum pt for at least one jet
> > 0.0 = xptb ! minimum pt for at least one b
> > 0.0 = xpta ! minimum pt for at least one photon
> > 0.0 = xptl ! minimum pt for at least one charged lepton
> > #*********************************************************************
> > # Control the pt's of the jets sorted by pt *
> > #*********************************************************************
> > 0.0 = ptj1min ! minimum pt for the leading jet in pt
> > 0.0 = ptj2min ! minimum pt for the second jet in pt
> > 0.0 = ptj3min ! minimum pt for the third jet in pt
> > 0.0 = ptj4min ! minimum pt for the fourth jet in pt
> > -1.0 = ptj1max ! maximum pt for the leading jet in pt
> > -1.0 = ptj2max ! maximum pt for the second jet in pt
> > -1.0 = ptj3max ! maximum pt for the third jet in pt
> > -1.0 = ptj4max ! maximum pt for the fourth jet in pt
> > 0 = cutuse ! reject event if fails any (0) / all (1) jet pt cuts
> > #*********************************************************************
> > # Control the pt's of leptons sorted by pt *
> > #*********************************************************************
> > 0.0 = ptl1min ! minimum pt for the leading lepton in pt
> > 0.0 = ptl2min ! minimum pt for the second lepton in pt
> > 0.0 = ptl3min ! minimum pt for the third lepton in pt
> > 0.0 = ptl4min ! minimum pt for the fourth lepton in pt
> > -1.0 = ptl1max ! maximum pt for the leading lepton in pt
> > -1.0 = ptl2max ! maximum pt for the second lepton in pt
> > -1.0 = ptl3max ! maximum pt for the third lepton in pt
> > -1.0 = ptl4max ! maximum pt for the fourth lepton in pt
> > #*********************************************************************
> > # Control the Ht(k)=Sum of k leading jets *
> > #*********************************************************************
> > 0.0 = htjmin ! minimum jet HT=Sum(jet pt)
> > -1.0 = htjmax ! maximum jet HT=Sum(jet pt)
> > 0.0 = ihtmin !inclusive Ht for all partons (including b)
> > -1.0 = ihtmax !inclusive Ht for all partons (including b)
> > 0.0 = ht2min ! minimum Ht for the two leading jets
> > 0.0 = ht3min ! minimum Ht for the three leading jets
> > 0.0 = ht4min ! minimum Ht for the four leading jets
> > -1.0 = ht2max ! maximum Ht for the two leading jets
> > -1.0 = ht3max ! maximum Ht for the three leading jets
> > -1.0 = ht4max ! maximum Ht for the four leading jets
> > #***********************************************************************
> > # Photon-isolation cuts, according to hep-ph/9801442 *
> > # When ptgmin=0, all the other parameters are ignored *
> > # When ptgmin>0, pta and draj are not going to be used *
> > #***********************************************************************
> > 0.0 = ptgmin ! Min photon transverse momentum
> > 0.4 = R0gamma ! Radius of isolation code
> > 1.0 = xn ! n parameter of eq.(3.4) in hep-ph/9801442
> > 1.0 = epsgamma ! epsilon_gamma parameter of eq.(3.4) in hep-ph/9801442
> > True = isoEM ! isolate photons from EM energy (photons and leptons)
> > #*********************************************************************
> > # WBF cuts *
> > #*********************************************************************
> > 0.0 = xetamin ! minimum rapidity for two jets in the WBF case
> > 0.0 = deltaeta ! minimum rapidity for two jets in the WBF case
> > #*********************************************************************
> > # KT DURHAM CUT *
> > #*********************************************************************
> > -1.0 = ktdurham
> > 0.4 = dparameter
> > #*********************************************************************
> > # maximal pdg code for quark to be considered as a light jet *
> > # (otherwise b cuts are applied) *
> > #*********************************************************************
> > 5 = maxjetflavor ! Maximum jet pdg code
> > #*********************************************************************
> > # Jet measure cuts *
> > #*********************************************************************
> > 0.0 = xqcut ! minimum kt jet measure between partons
> > #*********************************************************************
> > #
> > #*********************************************************************
> > # Store info for systematics studies *
> > # WARNING: If use_syst is T, matched Pythia output is *
> > # meaningful ONLY if plotted taking matchscale *
> > # reweighting into account! *
> > #*********************************************************************
> > True = use_syst ! Enable systematics studies
> > #
> > #**************************************
> > # Parameter of the systematics study
> > # will be used by SysCalc (if installed)
> > #**************************************
> > #
> > 0.5 1 2 = sys_scalefact # factorization/renormalization scale factor
> > 0.5 1 2 = sys_alpsfact # \alpha_s emission scale factors
> > 30 50 = sys_matchscale # variation of merging scale
> > # PDF sets and number of members (0 or none for all members).
> > Ct10nlo.LHgrid = sys_pdf # matching scales
> > # MSTW2008nlo68cl.LHgrid 1 = sys_pdf
> >
> >
> >
> > --
> > You received this question notification because you are an answer
> > contact for MadGraph5_aMC@NLO.
>
> --
> If this answers your question, please go to the following page to let us
> know that it is solved:
>
> https://answers.launchpad.net/mg5amcnlo/+question/270897/+confirm?answer_id=0
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
> https://answers.launchpad.net/mg5amcnlo/+question/270897
>
> You received this question notification because you asked the question.
>

You need at least xqcut to be different of zero.

I would strongly suggest that you look at our online help concerning matching/merging

Cheers,

Olivier
On 01 Sep 2015, at 22:26, miranda <email address hidden> wrote:

> Question #270897 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/270897
>
> Status: Answered => Open
>
> miranda is still having a problem:
> Dear Dr Olivier Mattelaer
>
>
> Thank you for your response. I really appreciate your advice.
>
> Could you please guide me again?
>
> About parton shower, is it enough to run the pythia shower: pythia=ON
>
> and run with MLM matching (the options ickkw=1 in the run_card.dat)
>
> Or I have to change "xqcut" and other options?
>
>
> Best Regards
> Miranda
>
> On Sun, Aug 30, 2015 at 1:16 AM, Olivier Mattelaer <
> <email address hidden>> wrote:
>
>> Your question #270897 on MadGraph5_aMC@NLO changed:
>> https://answers.launchpad.net/mg5amcnlo/+question/270897
>>
>> Status: Open => Answered
>>
>> Olivier Mattelaer proposed the following answer:
>> Hi,
>>
>> This is a very detailed question which is impossible for us to answer
>> without making a full analysis on such ratio. But this is the reflexion
>> that I have on your approach.
>>
>> 1) Why do you use a five flavour matching (all b/c jet are massless and
>> indistinguishable) for such comparison, Should not you use a three/four
>> flavour matching?
>> and therefore have not b/c present in the pdf?
>> 2) Should not you use a matched/merged generation for such type of
>> computation? This is particularly important for you pt cut.
>> 3) Due to you pt_j cut, I do not expect that the computation in MG and PY
>> matches, since it is likely that the pt cut applied not on the 2 > 2
>> particles but on the QCD radiation associated to the events.
>> In other word you need to simulate the shower (and in preference in a
>> matched/merged generation)
>>
>> Cheers,
>>
>> Olivier
>>
>>
>> On 29 Aug 2015, at 18:31, miranda <email address hidden>
>> wrote:
>>
>>> New question #270897 on MadGraph5_aMC@NLO:
>>> https://answers.launchpad.net/mg5amcnlo/+question/270897
>>>
>>> Dear Authors
>>> I am trying to compute the ratio of cross section (p p~ > z c) / (p p~ >
>> z b) to comparison with measurement was carried out by D0 (arXiv:1308.4384).
>>> But I got into trouble with this project and tried different ways to
>> solve it, but my efforts failed.
>>> As a last resort I decided to ask you to help me.
>>> Could you please guide me to solve it?
>>> define p = p b b~
>>> define j = j b b~
>>> generate p p > z c for p p~ > z c
>>> generate p p > z b for p p~ > z b
>>>
>>> then I divide the results of the cross section (z c and z b) for PT
>> (j_1) available in HTML folder.
>>> when I compared my results with the results of that paper, I found that
>> my results are different while I set
>>> the same cut as that paper’s.
>>> I don’t expect that my results reach the data, but I expect they will be
>> close to Pythia.
>>> I sent you the runcard that we used.
>>> Please let me know your idea about this.
>>> I look forward hearing from you.
>>> Thank you in advance
>>>
>>> #*********************************************************************
>>> # MadGraph5_aMC@NLO *
>>> # *
>>> # run_card.dat MadEvent *
>>> # *
>>> # This file is used to set the parameters of the run. *
>>> # *
>>> # Some notation/conventions: *
>>> # *
>>> # Lines starting with a '# ' are info or comments *
>>> # *
>>> # mind the format: value = variable ! comment *
>>> #*********************************************************************
>>> #
>>> #*******************
>>> # Running parameters
>>> #*******************
>>> #
>>> #*********************************************************************
>>> # Tag name for the run (one word) *
>>> #*********************************************************************
>>> tag_1 = run_tag ! name of the run
>>> #*********************************************************************
>>> # Run to generate the grid pack *
>>> #*********************************************************************
>>> False = gridpack !True = setting up the grid pack
>>> #*********************************************************************
>>> # Number of events and rnd seed *
>>> # Warning: Do not generate more than 1M events in a single run *
>>> # If you want to run Pythia, avoid more than 50k events in a run. *
>>> #*********************************************************************
>>> 10000 = nevents ! Number of unweighted events requested
>>> 0 = iseed ! rnd seed (0=assigned automatically=default))
>>> #*********************************************************************
>>> # Collider type and energy *
>>> # lpp: 0=No PDF, 1=proton, -1=antiproton, 2=photon from proton, *
>>> # 3=photon from electron *
>>> #*********************************************************************
>>> 1 = lpp1 ! beam 1 type
>>> -1 = lpp2 ! beam 2 type
>>> 980.0 = ebeam1 ! beam 1 total energy in GeV
>>> 980.0 = ebeam2 ! beam 2 total energy in GeV
>>> #*********************************************************************
>>> # Beam polarization from -100 (left-handed) to 100 (right-handed) *
>>> #*********************************************************************
>>> 0.0 = polbeam1 ! beam polarization for beam 1
>>> 0.0 = polbeam2 ! beam polarization for beam 2
>>> #*********************************************************************
>>> # PDF CHOICE: this automatically fixes also alpha_s and its evol. *
>>> #*********************************************************************
>>> 'cteq6l1' = pdlabel ! PDF set (lhapdf for using lhapdf)
>>> 10042 = lhaid ! PDF number used ONLY for LHAPDF
>>> #*********************************************************************
>>> # Renormalization and factorization scales *
>>> #*********************************************************************
>>> False = fixed_ren_scale ! if .true. use fixed ren scale
>>> False = fixed_fac_scale ! if .true. use fixed fac scale
>>> 91.188 = scale ! fixed ren scale
>>> 91.188 = dsqrt_q2fact1 ! fixed fact scale for pdf1
>>> 91.188 = dsqrt_q2fact2 ! fixed fact scale for pdf2
>>> -1 = dynamical_scale_choice ! Select one of the preselect dynamical
>> choice
>>> 1.0 = scalefact ! scale factor for event-by-event scales
>>> #*********************************************************************
>>> # Time of flight information. (-1 means not run)
>>> #*********************************************************************
>>> -1.0 = time_of_flight ! threshold below which info is not written
>>> #*********************************************************************
>>> # Matching - Warning! ickkw > 1 is still beta
>>> #*********************************************************************
>>> 0 = 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
>>> False = chcluster ! cluster only according to channel diag
>>> True = pdfwgt ! for ickkw=1, perform pdf reweighting
>>> 5 = asrwgtflavor ! highest quark flavor for a_s reweight
>>> True = 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)
>>> #**********************************************************
>>> True = auto_ptj_mjj ! Automatic setting of ptj and mjj
>>> #**********************************************************
>>> #
>>> #**********************************
>>> # BW cutoff (M+/-bwcutoff*Gamma)
>>> #**********************************
>>> 15.0 = 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)
>>> #**********************************************************
>>> False = 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) *
>>> #*********************************************************************
>>> 20.0 = ptj ! minimum pt for the jets
>>> 0.0 = ptb ! minimum pt for the b
>>> 0.0 = pta ! minimum pt for the photons
>>> 0.0 = ptl ! minimum pt for the charged leptons
>>> 0.0 = misset ! minimum missing Et (sum of neutrino's momenta)
>>> 0.0 = ptheavy ! minimum pt for one heavy final state
>>> -1.0 = ptjmax ! maximum pt for the jets
>>> -1.0 = ptbmax ! maximum pt for the b
>>> -1.0 = ptamax ! maximum pt for the photons
>>> -1.0 = ptlmax ! maximum pt for the charged leptons
>>> -1.0 = missetmax ! maximum missing Et (sum of neutrino's momenta)
>>> #*********************************************************************
>>> # Minimum and maximum E's (in the center of mass frame) *
>>> #*********************************************************************
>>> 0.0 = ej ! minimum E for the jets
>>> 0.0 = eb ! minimum E for the b
>>> 0.0 = ea ! minimum E for the photons
>>> 0.0 = el ! minimum E for the charged leptons
>>> -1.0 = ejmax ! maximum E for the jets
>>> -1.0 = ebmax ! maximum E for the b
>>> -1.0 = eamax ! maximum E for the photons
>>> -1.0 = elmax ! maximum E for the charged leptons
>>> #*********************************************************************
>>> # Maximum and minimum absolute rapidity (for max, -1 means no cut) *
>>> #*********************************************************************
>>> 2.5 = etaj ! max rap for the jets
>>> -1.0 = etab ! max rap for the b
>>> -1.0 = etaa ! max rap for the photons
>>> -1.0 = etal ! max rap for the charged leptons
>>> 0.0 = etajmin ! min rap for the jets
>>> 0.0 = etabmin ! min rap for the b
>>> 0.0 = etaamin ! min rap for the photons
>>> 0.0 = etalmin ! main rap for the charged leptons
>>> #*********************************************************************
>>> # Minimum and maximum DeltaR distance *
>>> #*********************************************************************
>>> 0.0 = drjj ! min distance between jets
>>> 0.0 = drbb ! min distance between b's
>>> 0.0 = drll ! min distance between leptons
>>> 0.0 = draa ! min distance between gammas
>>> 0.0 = drbj ! min distance between b and jet
>>> 0.0 = draj ! min distance between gamma and jet
>>> 0.0 = drjl ! min distance between jet and lepton
>>> 0.0 = drab ! min distance between gamma and b
>>> 0.0 = drbl ! min distance between b and lepton
>>> 0.0 = dral ! min distance between gamma and lepton
>>> -1.0 = drjjmax ! max distance between jets
>>> -1.0 = drbbmax ! max distance between b's
>>> -1.0 = drllmax ! max distance between leptons
>>> -1.0 = draamax ! max distance between gammas
>>> -1.0 = drbjmax ! max distance between b and jet
>>> -1.0 = drajmax ! max distance between gamma and jet
>>> -1.0 = drjlmax ! max distance between jet and lepton
>>> -1.0 = drabmax ! max distance between gamma and b
>>> -1.0 = drblmax ! max distance between b and lepton
>>> -1.0 = dralmax ! maxdistance between gamma and lepton
>>> #*********************************************************************
>>> # Minimum and maximum invariant mass for pairs *
>>> # WARNING: for four lepton final state mmll cut require to have *
>>> # different lepton masses for each flavor! *
>>> #*********************************************************************
>>> 0.0 = mmjj ! min invariant mass of a jet pair
>>> 0.0 = mmbb ! min invariant mass of a b pair
>>> 0.0 = mmaa ! min invariant mass of gamma gamma pair
>>> 0.0 = mmll ! min invariant mass of l+l- (same flavour) lepton pair
>>> -1.0 = mmjjmax ! max invariant mass of a jet pair
>>> -1.0 = mmbbmax ! max invariant mass of a b pair
>>> -1.0 = mmaamax ! max invariant mass of gamma gamma pair
>>> -1.0 = mmllmax ! max invariant mass of l+l- (same flavour) lepton pair
>>> #*********************************************************************
>>> # Minimum and maximum invariant mass for all letpons *
>>> #*********************************************************************
>>> 0.0 = mmnl ! min invariant mass for all letpons (l+- and vl)
>>> -1.0 = mmnlmax ! max invariant mass for all letpons (l+- and vl)
>>> #*********************************************************************
>>> # Minimum and maximum pt for 4-momenta sum of leptons *
>>> #*********************************************************************
>>> 0.0 = ptllmin ! Minimum pt for 4-momenta sum of leptons(l and vl)
>>> -1.0 = ptllmax ! Maximum pt for 4-momenta sum of leptons(l and vl)
>>> #*********************************************************************
>>> # Inclusive cuts *
>>> #*********************************************************************
>>> 0.0 = xptj ! minimum pt for at least one jet
>>> 0.0 = xptb ! minimum pt for at least one b
>>> 0.0 = xpta ! minimum pt for at least one photon
>>> 0.0 = xptl ! minimum pt for at least one charged lepton
>>> #*********************************************************************
>>> # Control the pt's of the jets sorted by pt *
>>> #*********************************************************************
>>> 0.0 = ptj1min ! minimum pt for the leading jet in pt
>>> 0.0 = ptj2min ! minimum pt for the second jet in pt
>>> 0.0 = ptj3min ! minimum pt for the third jet in pt
>>> 0.0 = ptj4min ! minimum pt for the fourth jet in pt
>>> -1.0 = ptj1max ! maximum pt for the leading jet in pt
>>> -1.0 = ptj2max ! maximum pt for the second jet in pt
>>> -1.0 = ptj3max ! maximum pt for the third jet in pt
>>> -1.0 = ptj4max ! maximum pt for the fourth jet in pt
>>> 0 = cutuse ! reject event if fails any (0) / all (1) jet pt cuts
>>> #*********************************************************************
>>> # Control the pt's of leptons sorted by pt *
>>> #*********************************************************************
>>> 0.0 = ptl1min ! minimum pt for the leading lepton in pt
>>> 0.0 = ptl2min ! minimum pt for the second lepton in pt
>>> 0.0 = ptl3min ! minimum pt for the third lepton in pt
>>> 0.0 = ptl4min ! minimum pt for the fourth lepton in pt
>>> -1.0 = ptl1max ! maximum pt for the leading lepton in pt
>>> -1.0 = ptl2max ! maximum pt for the second lepton in pt
>>> -1.0 = ptl3max ! maximum pt for the third lepton in pt
>>> -1.0 = ptl4max ! maximum pt for the fourth lepton in pt
>>> #*********************************************************************
>>> # Control the Ht(k)=Sum of k leading jets *
>>> #*********************************************************************
>>> 0.0 = htjmin ! minimum jet HT=Sum(jet pt)
>>> -1.0 = htjmax ! maximum jet HT=Sum(jet pt)
>>> 0.0 = ihtmin !inclusive Ht for all partons (including b)
>>> -1.0 = ihtmax !inclusive Ht for all partons (including b)
>>> 0.0 = ht2min ! minimum Ht for the two leading jets
>>> 0.0 = ht3min ! minimum Ht for the three leading jets
>>> 0.0 = ht4min ! minimum Ht for the four leading jets
>>> -1.0 = ht2max ! maximum Ht for the two leading jets
>>> -1.0 = ht3max ! maximum Ht for the three leading jets
>>> -1.0 = ht4max ! maximum Ht for the four leading jets
>>> #***********************************************************************
>>> # Photon-isolation cuts, according to hep-ph/9801442 *
>>> # When ptgmin=0, all the other parameters are ignored *
>>> # When ptgmin>0, pta and draj are not going to be used *
>>> #***********************************************************************
>>> 0.0 = ptgmin ! Min photon transverse momentum
>>> 0.4 = R0gamma ! Radius of isolation code
>>> 1.0 = xn ! n parameter of eq.(3.4) in hep-ph/9801442
>>> 1.0 = epsgamma ! epsilon_gamma parameter of eq.(3.4) in hep-ph/9801442
>>> True = isoEM ! isolate photons from EM energy (photons and leptons)
>>> #*********************************************************************
>>> # WBF cuts *
>>> #*********************************************************************
>>> 0.0 = xetamin ! minimum rapidity for two jets in the WBF case
>>> 0.0 = deltaeta ! minimum rapidity for two jets in the WBF case
>>> #*********************************************************************
>>> # KT DURHAM CUT *
>>> #*********************************************************************
>>> -1.0 = ktdurham
>>> 0.4 = dparameter
>>> #*********************************************************************
>>> # maximal pdg code for quark to be considered as a light jet *
>>> # (otherwise b cuts are applied) *
>>> #*********************************************************************
>>> 5 = maxjetflavor ! Maximum jet pdg code
>>> #*********************************************************************
>>> # Jet measure cuts *
>>> #*********************************************************************
>>> 0.0 = xqcut ! minimum kt jet measure between partons
>>> #*********************************************************************
>>> #
>>> #*********************************************************************
>>> # Store info for systematics studies *
>>> # WARNING: If use_syst is T, matched Pythia output is *
>>> # meaningful ONLY if plotted taking matchscale *
>>> # reweighting into account! *
>>> #*********************************************************************
>>> True = use_syst ! Enable systematics studies
>>> #
>>> #**************************************
>>> # Parameter of the systematics study
>>> # will be used by SysCalc (if installed)
>>> #**************************************
>>> #
>>> 0.5 1 2 = sys_scalefact # factorization/renormalization scale factor
>>> 0.5 1 2 = sys_alpsfact # \alpha_s emission scale factors
>>> 30 50 = sys_matchscale # variation of merging scale
>>> # PDF sets and number of members (0 or none for all members).
>>> Ct10nlo.LHgrid = sys_pdf # matching scales
>>> # MSTW2008nlo68cl.LHgrid 1 = sys_pdf
>>>
>>>
>>>
>>> --
>>> You received this question notification because you are an answer
>>> contact for MadGraph5_aMC@NLO.
>>
>> --
>> If this answers your question, please go to the following page to let us
>> know that it is solved:
>>
>> https://answers.launchpad.net/mg5amcnlo/+question/270897/+confirm?answer_id=0
>>
>> If you still need help, you can reply to this email or go to the
>> following page to enter your feedback:
>> https://answers.launchpad.net/mg5amcnlo/+question/270897
>>
>> You received this question notification because you asked the question.
>>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.