Issue with m_ll cut in pp > w+l+l- process with new physics model

Hi,

Can you try with the latest version of the code 2.1.2. I’m quite confident that your problem might be already solve in the latest version.
(and that version include the reweighting functionality)

Cheers,

Olivier

On Jul 8, 2014, at 7:47 AM, Kenneth Long <email address hidden> wrote:

> New question #251340 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/251340
>
> Hi Experts,
>
> I am generating the process p p > w+ l+ l- QED = 6 QCD = 0, w+ > l+ vl to include Z/gamma interference for studies of W+Z vector boson fusion events. I am using the model SM_LT012 (http://feynrules.irmp.ucl.ac.be/wiki/AnomalousGaugeCoupling) to study anomalous quartic gauge couplings. I am using version 2.0.0beta4 as I am interested in using the new reweight feature after I have successfully generated the process.
>
> I am encountering an issue with divergences and very large cross sections for certain values in run_card.dat. Here is the run card I am using: http://www.hep.wisc.edu/~kdlong/Madgraph_wpz_zg_runinfo/run_card_10000.dat
>
> My intention is to closely follow the CMS recommended card, found here: https://twiki.cern.ch/twiki/bin/viewauth/CMS/MadGraphFall13Production
>
> My cuts are slightly looser than the recommended ones, for example, setting ptl from 0 to 5 GeV and dell from 0.0 to 0.001, which are necessary to have the process generation converge at all. My assumption was that m_ll > 12 GeV would serve to remove the photon pole at zero, but in the following plot, (made with events generated from the above run_card.dat) this does not appear to be the case, as a strong contribution of m_ll = 0 is evident.
>
> http://www.hep.wisc.edu/~kdlong/Madgraph_wpz_zg_runinfo/wpz_zg_2mu10000ev.png
>
> Running the same process with another run_card.dat (below) with looser ptl cuts is even more severe, as the cross section for the total process is calculated very high, 188 pb, and virtually all of the events have m_ll = 0.
>
> http://www.hep.wisc.edu/~kdlong/Madgraph_wpz_zg_runinfo/run_card_100000.dat
> http://www.hep.wisc.edu/~kdlong/Madgraph_wpz_zg_runinfo/wpz_zg_2mu100000ev.png
>
> Both process were generated with this param_card.dat and process_card.dat:
>
> http://www.hep.wisc.edu/~kdlong/Madgraph_wpz_zg_runinfo/proc_card_mg5.dat
> http://www.hep.wisc.edu/~kdlong/Madgraph_wpz_zg_runinfo/param_card.dat
>
> Can you enlighten me on how these cuts are applied? What would you recommend to remove the divergences without losing the effects of the lower p_T and deltaEta leptons?
>
>
>
> Thanks for the help,
>
> Kenneth
>
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