The events I could produce with this gridpack are OK for a study where I try to demonstrate that a measurement of the background from data is correct? I had a look at these events with delphes and there are (as expected) few events with m(ll) in the range I’d like to study… not many but producing a lot of events I could have enough of them to do some basic study… So my question is: The situation I have is the following… I’m trying to have a reasonable prediction of the background due to DY events with mu+mu- in the mass range 11GeV Thanks for the clarification… just let me ask one more question. Maybe down to 5 GeV, but certainly not below that. Hence, to be short, I don't think it's possible to go well below the 10 GeV lepton invariant mass cut. However, this clearly goes into the non-perturbative region which cannot be correctly simulated with methods based on perturbation theory, such as matrix elements and FxFx merging (and it definitely does not make sense to try to include NLO corrections). So, the merging scale should be 1 or 2 GeV at most, which also means that the generation cut on the jet pT should be reduced considerably. And the merging scale should be smaller than the typical hard scale of the process. I guess that this is for a merging scale of 20-30 GeV or so, right? However, this cannot be consistent: with the 1 GeV < m_ll <10 GeV cuts, the typical scale of your process is only a couple of GeV. I also see that the lower generation cut on the jet pT is 10 GeV. I think you seriously need to increase this cut. In this region perturbation theory doesn't work very well, and I'm not surprised that the code doesn't converge properly and you get either zero, NaN, or other non-sensical results. I believe the problem is the very low invariant mass cut on the leptons. The gridpack is dyellell012j_5f_NLO_FXFX_M1toInf_slc6_amd64_gcc481_CMSSW_7_1_28_ in the following directory: pool/lsf/santocch/88864664/dyellell012j_5f_NLO_FXFX_M1toInf/dyellell012j_5f_NLO_FXFX_M1toInf_gridpack/work/processtmp/SubProcesses/P2_dd_epemdd/GF1/UPS.log Maximum fraction of UPS points in channel processtmp/SubProcesses/P2_dd_epemdd/GF1 (0.01%) well just tell me and I will try to find another solution for the small m(ll) range. tar.xz in the following directory:Ĭould you have a look and give me some hint on how to proceed? I really don't know what to try now and. The gridpack is dyellell012j_ 5f_NLO_ FXFX_M1toInf_ slc6_amd64_ gcc481_ CMSSW_7_ 1_28_tarball. pool/ lsf/santocch/ 88864664/ dyellell012j_ 5f_NLO_ FXFX_M1toInf/ dyellell012j_ 5f_NLO_ FXFX_M1toInf_ gridpack/ work/processtmp /SubProcesses/ P2_dd_epemdd/ GF1/UPS. Please report this to the authors while providing the file Maximum fraction of UPS points in channel processtmp/ SubProcesses/ P2_dd_epemdd/ GF1 (0.01%) Total number of unstable PS point detected: 5 (0.00%) Number of loop ME evaluations (by MadLoop): 5377389 Process p p > ell+ ell- p p > ell+ ell- j p p > ell+ ell- j j at p-p collider (6500.0 + 6500.0 GeV) Is that a problem? The final cross section seems to me strange: INFO: Updating the number of unweighted events per channel The gridpack has been produced but in the log file I see the following lines: Generate p p > ell+ ell- process p p > ell+ ell- j process p p > ell+ ell- j j any upper bound on m(ll) and using:ġ.0 = mll_sf ! Min inv. I'm still trying to find a way to have DY events with m(ll) in the range 1-10GeV. The lower cut on m(ll) is defined in the run.card while the upper bound is defined in a cut.f file.ģ) The process is include the ll+0jet, ll+1jet and ll+2jet.Ĥ) The error and the card used are in the link belowĥ) I tried to split the process and the ll+0jet is the problem, the ll+1jet is correctly run and the ll+2j is running right and I don't know yet if it will complete or not but I already know that the ll+0jet process is the problemĬould you give some indication on how to solve the problem? Here is the situation:ġ) CMS collaboration use a specific script to run on LSF at cern the gridpack generation and different cards have been used several times to produce different gridpack process.Ģ) The specific process is a Drell-Yan production at NLO with 1GeV50GeV). I'm trying to generate Drell-Yan events at NLO and I got some errors which I'm not able to solve.
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