1. Fortran HERWIG Status Report and Validation in Athena rel. 14 By Jon Butterworth (UCL) Claire Gwenlan (Oxford) Alessandro Tricoli (RAL) ATLAS MC Generator Meeting, 11 th December 2008

2. HERWIG status report Many changes in Herwig_i interface Many changes in Herwig_i interface from last MC Validation Meeting: From Herwig_i-00-03-03 to Herwig_i-00-03-15 –some related to Charybdis and Alpgen Fixes in Herwig_i-00-03-10Fixes in Herwig_i-00-03-10 –addition of Horace to the interface as external generator: In Herwig_i-00-3-13In Herwig_i-00-3-13 –addition of RPV code to Herwig (in a seperate library): in Herwig_i-00-3-10, fixes in Herwig_i-00-3-12in Herwig_i-00-3-10, fixes in Herwig_i-00-3-12 –fix of the Low Mass Z "ears" in eta ME correction did not preserve the rapidity of the vector boson in the hard process. Large effect for small x (corrections are enhanced by 1/x)ME correction did not preserve the rapidity of the vector boson in the hard process. Large effect for small x (corrections are enhanced by 1/x) Modified routine hwbdyp.f (ME corrections for DY processes) in Herwig_i-00-03-13Modified routine hwbdyp.f (ME corrections for DY processes) in Herwig_i-00-03-13 bug-fix release of Fortran Herwig “Herwig 6.511” due to come out soon.bug-fix release of Fortran Herwig “Herwig 6.511” due to come out soon. –fix of the Higgs->WW decays: reported by the Higgs group, fixed by Bryan Webber and Jon Butterworth, and checked by Tiesheng Dai in Herwig_i-00-03-15reported by the Higgs group, fixed by Bryan Webber and Jon Butterworth, and checked by Tiesheng Dai in Herwig_i-00-03-15 Bug in the fix corrected in Herwig_i-00-03-15Bug in the fix corrected in Herwig_i-00-03-15 –several changes & fixes to the parameter setting in the interface: More steerable parametersMore steerable parameters Latest fixes in Herwig_i-00-03-15Latest fixes in Herwig_i-00-03-15 Latest Tags Herwig_i-00-03-15 ← CVS tag HEAD Herwig_i-00-03-13 ← 14.4.0.1 release

3. HERWIG status report Low Mass Z Rapidity “ears” old version of hwbdyp.f new version of hwbdyp.f Test done by Claire Gwenlan in Fortran Herwig stand-alone (before its implementation in ATHENA) The fix has to be checked withn ATNENA (to do list)

4. HERWIG SM validation status report Sample B (14.4.0.1) AODs Sample B (14.4.0.1) AODs Herwig_i-00-03-13:  valid1.105100.JimmyWenu.recon.a78 MC8 series (10 TeV)  500K events!! (Thanks to Osamu)  W and Electron plots look OK:  comparison OK with 10 TeV ref. plots from previous Sample B (14.2.0.2, conf tag a64) (see extra slides for more plots) Private production 14.4.0.1 Herwig_i-00-03-15: (small samples)  W→e sample  Comparison OK with Herwig_i-00-03-13 (Sample B) for W and Electron plots  Z→ee sample  Z and Electron distributions look OK W rapidity W p T 14.4.0.1 (Sample-B 10 TeV) 14.2.0.1 (REF, Sample-B 10 TeV) Ratio

5. HERWIG SUSY validation status report Sample B (14.4.0.1) AODs Sample B (14.4.0.1) AODs Herwig_i-00-03-13:  valid1.105403.SU3_jimmy_susy.recon.a78 MC8 series (10 TeV)  plots look OK compared to ref. plots from previous SampleB (14.2.20.1, config tag a70) more plots in extras C4 truth jets MET electronsmuons

6. EXTRA SLIDES

7. Sample-B Plots rel 14.4.0.1, 10 TeV, config tag a78 500K events Using MC8.105100.JimmyWenu.py c sc_evgenTruthJetMet08_trf.py Thanks to Osamu!! Compared to previous 10 TeV Sample-B: rel 14.2.0.2, 10 TeV, config tag a64 50 K events valid1.105100.JimmyWenu.recon.a78

8. HERWIG SM validation W Boson 14.4.0.1 (Sample-B 10 TeV) 14.2.0.1 (REF, Sample-B 10 TeV) W p T W Mass W y Ratio

9. HERWIG SM validation W ± Bosons W- y W+ y 14.4.0.1 (Sample-B 10 TeV) 14.2.0.1 (REF, Sample-B 10 TeV) W+ pT W- pT Ratio

10. HERWIG SM validation Final State Electrons (status==1) From W decay e-e+ e±e± 14.4.0.1 (Sample-B 10 TeV) 14.2.0.1 (REF, Sample-B 10 TeV) Ratio

11. HERWIG SM validation Final State Electrons (status==1) From W decay e-e+ ele p T 14.4.0.1 (Sample-B 10 TeV) 14.2.0.1 (REF, Sample-B 10 TeV) Ratio

12. HERWIG SM validation Charge Asymmetry in W events W Electron W + - W - W + + W - e + - e - e + + e - 14.4.0.1 (Sample-B 10 TeV) 14.2.0.1 (REF, Sample-B 10 TeV) Ratio

13. Sample-B Plots rel 14.4.0.1, 10 TeV, config tag a78 50K events Using MC8.105403.SU3_jimmy_susy.py csc_evgenTruthJetMet08_trf.py Thanks to Osamu!! Compared to previous 10 TeV samples (all 50K events): - rel 14.2.20.1 SampleB, 10 TeV, config tag a70 - rel 14.2.0.2 SampleB, 10 TeV, config tag a64 - rel 12.0.6, 10 TeV (privately produced) valid1.105403.SU3_jimmy_susy.recon.a78

14. MET quantities HERWIG SUSY validation Note: samples from 14.4.0.1 and 14.2.20.1 use the new SUSY SU3 spectrum/decay file 14.2.0.2 and 12.0.6 use the old s/d file, but are shown here to illustrate differences arising from those different files [ for further details on the old versus new spectrum/decay files see fHerwig status report from 9 th Sept 2008]

15. electron quantities HERWIG SUSY validation slight spread in electron mass in 14.4.0.1?

16. muon quantities HERWIG SUSY validation

17. photon quantities HERWIG SUSY validation Differences observed presumably due to the fact that pions from taus were not being decayed in previous rel14 samples (see fHerwig report from 9 th Sept. 2008). This is now fixed…

18. dilepton masses HERWIG SUSY validation OSSF elecs+muons SSSF elecs+muons OSSF electronsOSSF muons

19. jet quantities HERWIG SUSY validation