1 / 26

AA->HH Study ~About the Neural Network analysis and other issues~

AA->HH Study ~About the Neural Network analysis and other issues~. Shin-ichi Kawada (Advanced Science of Matter, Hiroshima University). About PLC. Electrons. Backward Compton scattering. Photon-photon collision. Reaction in photon-photon collision. Signal: gamma ・ gamma->HH

najila
Download Presentation

AA->HH Study ~About the Neural Network analysis and other issues~

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. AA->HH Study~About the Neural Network analysis and other issues~ Shin-ichi Kawada (Advanced Science of Matter, Hiroshima University) 16th ILC general meeting (2010/7/17)

  2. About PLC Electrons Backward Compton scattering Photon-photon collision 16th ILC general meeting (2010/7/17)

  3. Reaction in photon-photon collision • Signal: gamma・gamma->HH • Final goal: measurement of higgs self-coupling constant • Many backgrounds • gamma・gamma->WW, ZZ, 4b, etc... • Analysis of background reduction is necessary. • It was assumed that higgs mass is 120GeV in this study. 16th ILC general meeting (2010/7/17)

  4. Main backgrounds Optimized CM energy: 270GeV There are 2 main backgrounds. gamma・gamma->WW (11.6pb) gamma・gamma->ZZ (9.42fb) (studied by N.Maeda) 16th ILC general meeting (2010/7/17)

  5. Previous results (studied by N.Maeda) • The neural network (NN) analysis can reduce WW backgrounds. • However, ZZ backgrounds remain because of inaccuracy from the jet clustering and the b-tagging. We will write the paper about the analysis of the background reduction using NN. 16th ILC general meeting (2010/7/17)

  6. Current issues • Toward the preparation of the paper, there are 3 issues to be solved. • Consideration of other backgrounds • Treatment of the ZZ events • Check of the NN training 16th ILC general meeting (2010/7/17)

  7. 1. Other backgrounds • We have to consider other intermediate states in gamma・gamma->4b. • We have asked Kurihara-san to calculate the cross-section of gamma・gamma->4b. 16th ILC general meeting (2010/7/17)

  8. 2. Treatment of ZZ events Present method ON-shell mode is helicity state. 1st step 2nd step γγ 4b ZZ ZZ More realistic method reaction γγ intermediate state including ZZ 4b OFF-shell mode is not helicity state. 16th ILC general meeting (2010/7/17)

  9. 2. Treatment of ZZ events • We have to compare the helicity amplitude using ON-shell mode with OFF-shell mode. 16th ILC general meeting (2010/7/17)

  10. ON-shell mode Results OFF-shell mode Cos(theta) CM energy Helicity Phi 16th ILC general meeting (2010/7/17)

  11. Results • ON-shell mode results and OFF-shell mode results are almost same. • ON-shell mode calculation is effective. • “Treatment of ZZ events” issue is solved! 16th ILC general meeting (2010/7/17)

  12. 3. Check of the NN training • We have to make an estimation of the systematic error from NN analysis. 16th ILC general meeting (2010/7/17)

  13. 3. Check of the NN training NN analysis (conventional) Training step some events signal file No.1 weight file No.1 NN some events BG file No.1 Analysis step weight file No.1 output ALL events Weight file No.1 depends on the signal file No.1 and BG file No.1. NN signal file No.1 ALL events BG file No.1 16th ILC general meeting (2010/7/17)

  14. 3. Check of the NN training We have to check of statistical independence. No.2 files are independent from No.1 files. Training step some events signal file No.2 weight file No.2 NN some events BG file No.2 Analysis step weight file No.2 (1) ALL events output NN signal file No.1 (2) ALL events BG file No.1 (2) 16th ILC general meeting (2010/7/17)

  15. Events file & weight file • There are 4 MC events files & 4 weight files. • Maeda MC events file & weight file • Kawada MC ON-shell events file & weight file • Kawada MC OFF-shell events file No.1 & weight file • Kawada MC OFF-shell events file No.2 & weight file • Events files: HH 50k events (signal) ZZ 1M events (BG) 16th ILC general meeting (2010/7/17)

  16. Pre-selection condition Condition of reconstructed particles These condition come from gamgamZZ-code. # of b-flavor jets (nsig=3.0 & noffv=1) > 2 # of b-flavor jets (nsig=3.0 & noffv=2) > 1 b-tagging 16th ILC general meeting (2010/7/17)

  17. Pre-selection # of remained events after pre-selection # of generate HH=50000 HH=29897 Maeda ZZ=1000000 ZZ=86538 HH=29958 HH=50000 Kawada-ON ZZ=87056 ZZ=1000000 HH=50000 HH=29958 Kawada-OFF1 ZZ=1000000 ZZ=87486 HH=50000 HH=29823 Kawada-OFF2 ZZ=1000000 ZZ=87143 These difference is caused by statistical fluctuation. 16th ILC general meeting (2010/7/17)

  18. How to check statistical independence 1. Preparation of weight files Example Kawada OFF1 signal file 29958 3000 (fixed) weight file Kawada OFF1 NN Kawada OFF1 BG file 87056 5000 (fixed) (4 events file) * (4 weight file) = (16 combinations) 2. We calculate the maximum significance for each combination. 3. We compare the values of significance to check the statistical independence among the combination. 16th ILC general meeting (2010/7/17)

  19. Combination results Kawada OFF1 Kawada ON Kawada OFF2 weights Maeda events 14086 4372 16051 6662 15520 5783 15078 5583 Maeda 1.34 1.25 1.29 1.28 29897 86538 Kawada-OFF1 11704 2197 13575 3057 13168 2896 13738 3057 29958 87056 1.53 1.52 1.52 1.54 Kawada-ON 12501 2603 13880 3293 14524 3488 13738 3144 1.51 1.51 1.50 1.52 29958 87486 Kawada-OFF2 12167 2389 12538 2575 12830 2723 13291 2846 29823 87143 1.53 1.53 1.52 1.54 # of remained HH,# of remained ZZ,Maximum significance 16th ILC general meeting (2010/7/17)

  20. Result & Discussion • Significance ~1.3 was obtained with Maeda events and there is large fluctuation. • Significance ~1.52 was obtained with Kawada events and there is small fluctuation. These fluctuation is caused by the statistical fluctuation among Kawada events. 16th ILC general meeting (2010/7/17)

  21. Result & Discussion • In Kawada events, maximum significance does not depend on the weight file. • It is still unclear what causes large fluctuation among the Maeda events. 16th ILC general meeting (2010/7/17)

  22. Summary • The status of 3 issues are presented as following. • Consideration of other backgrounds -> Kurihara-san • Treatment of ZZ events -> ON-shell mode calculation is effective. • Check of the NN training -> The fluctuation of significance is caused by the statistical fluctuation among Kawada events. 16th ILC general meeting (2010/7/17)

  23. Talk in JPS meeting • I will talk about AA->HH study topics in JPS. • English title: Feasibility study of the measurement of higgs pair creation in the photon-photon linear collider 16th ILC general meeting (2010/7/17)

  24. Backup slides 16th ILC general meeting (2010/7/17)

  25. ON-shell mode program ZZSpring.cxx HELVector z1im(fP[0]+fP[1], kM_z, -1, -1); HELVector z1i0(fP[0]+fP[1], kM_z, 0, -1); HELVector z1ip(fP[0]+fP[1], kM_z, -1, -1); This “kM_z” means ON-shell mode (91.19GeV). 16th ILC general meeting (2010/7/17)

  26. OFF-shell mode program ZZSpring.cxx Double_t forinvE1 = TMath::Power((fP[0].E() + fP[1].E()),2); Double_t forinvPx1 = TMath::Power((fP[0].Px() + fP[1].Px()),2); Double_t forinvPy1 = TMath::Power((fP[0].Py() + fP[1].Py()),2); Double_t forinvPz1 = TMath::Power((fP[0].Pz() + fP[1].Pz()),2); Double_t invmassZ1 = TMath::Sqrt(forinvE1 – forinvPx1 – forinvPy1 – forinvPz1); These parts show the calculation of invariant mass. HELVector z1im(fP[0]+fP[1], invmassZ1, -1, -1); HELVector z1i0(fP[0]+fP[1], invmassZ1, 0, -1); HELVector z1ip(fP[0]+fP[1], invmassZ1, -1, -1); This means invariant mass. 16th ILC general meeting (2010/7/17)

More Related