1 / 34

VBF H-> tt -> hadron+lepton 用の tauID の研究 ＆ 活動報告 ～ 2004 年のまとめ～

VBF H-> tt -> hadron+lepton 用の tauID の研究 ＆ 活動報告 ～ 2004 年のまとめ～. Junichi Tanaka ICEPP, University of Tokyo. 内容. VBF H-> tt ->hadron+lepton 用の tauID の研究 活動報告 Higgs WG SUSY WG 今後の予定. VBF H-> tt ->hadron+lepton 用の tauID の研究 （野本君の仕事の継続）. Contents. Motivation Strategy of tauID さまざまな分布

ulema
Télécharger la présentation

VBF H-> tt -> hadron+lepton 用の tauID の研究 ＆ 活動報告 ～ 2004 年のまとめ～

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. VBF H->tt->hadron+lepton用のtauIDの研究＆活動報告～2004年のまとめ～ Junichi Tanaka ICEPP, University of Tokyo ATLAS日本総会@河口湖

  2. 内容 • VBF H->tt->hadron+lepton用のtauIDの研究 • 活動報告 • Higgs WG • SUSY WG • 今後の予定 ATLAS日本総会@河口湖

  3. VBF H->tt->hadron+lepton用のtauIDの研究 （野本君の仕事の継続） ATLAS日本総会@河口湖

  4. Contents • Motivation • Strategy of tauID • さまざまな分布 • p0の取り扱い • How to identify tau-jet? • Improvement of taujet’s momentum • Pileup & Noise effect ATLAS日本総会@河口湖

  5. Motivation • VBF H->tt->hvtlvtvl is very important to discover Higgs at the low mass region. • ATL-PHYS-2003-004/005, ATL-COM-PHYS-2003-007 • Identification of hadronic tau is one of important things for this analysis. • Many variables are used to identify tau-jets. However most of them represent one characteristics of tau-jets. -> Narrow jets T.Takemoto (Univ. of Tokyo) ATLAS日本総会@河口湖

  6. Strategy of tauID • Use tau-jets with low Pt > 20GeV or 15GeV… • Properties of tau-jets. • Hadronic decay of tau-> Number of charged tracks and jet charge. • Narrow jets-> Fraction of energy in DR<0.1 • Shower shape related with decay products (p0,p+-) of t-> Distributions of fraction of energy at each layer. -> Can make a likelihood function from them. • Lifetime (ct~87mm) … not studied yet … ATLAS日本総会@河口湖

  7. Jet Charge • Number of charged tracks should be 1,2 and 3. -> Jet charge should be –2,–1, 0, +1 and +2. 30<Pt<40GeV 50<Pt<70GeV Tau QCD ATLAS日本総会@河口湖

  8. Fraction of energy in DR<0.1 • As Pt larger, a tau-jet becomes narrower.-> Fraction of energy in DR<0.1 (FDR<0.1) becomes larger! 20 < Pt < 30 40 < Pt < 50 70 < Pt < 130 Tau-jets QCD-jets Cut on FDR<0.1 is used to tune “effand R”. ATLAS日本総会@河口湖

  9. Distributions of fraction of energy at each layer • After applying the 3 criteria (Ntrk, Qjet, FDR<0.1),the following distributions are obtained. Due to no p0 jet PreEM Tau Layer1EM QCD 40<Pt<50GeV, |h|<1.8 ATLAS日本総会@河口湖

  10. 40<Pt<50GeV, |h|<1.8 Layer2EM Layer3EM Tau QCD Layer1Had LayerOthersHad • Distributions of remaining QCD-jets are similar with those of tau-jets. -> Not need to use them for tauID. ATLAS日本総会@河口湖

  11. p0 in jet • By using generator information, we check ratios of jets including p0. • Tau-jets20<Pt<30 GeV 40<Pt<50 70<Pt<130p0 = 0, p+- > 0 : 24% 22% 20%p0 > 0, p+- > 0 : 76% 78% 80% • QCD-jets 20<Pt<30 GeV 40<Pt<50 70<Pt<130p0 = 0, p+- > 0 : 11% 5% 2%p0 > 0, p+- > 0 : 88% 95% 98% • p0 information will be used for tauID. • For no p0, use looser cut ATLAS日本総会@河口湖

  12. How to identify p0 in jet? • By using DPtp0, we can determine if a jet has p0. DPtp0 = Pt of jet – S Pt of charged tracks Np0=0, Np+-=1 Np0=1, Np+-=3 DPtp0 (GeV) DPtp0 (GeV) ATLAS日本総会@河口湖

  13. How to identify tau-jet? Jet Check Ntrk + Qjet no Non-tauJet yes Cuts on FDR<0.1 aretuned for each category. Check DPtp0 < 10GeV p0 >0, p+- = 1~3 p0 = 0, p+- = 1 p0 = 0, p+- = 3 Check FDR<0.1 Check FDR<0.1 Check FDR<0.1 Tau-jet Non-tauJet ATLAS日本総会@河口湖

  14. Improvement of tau-jet’s momentum using charged trks • For no p0 tau-jet, we can use “S P of charged tracks” as a momentum of tau-jet. • Can improve resolution of mass of Higgs candidates.-> could improve tail of Z ->tt backgrounds. Np0=0, Np+-=1 Pt(Jet) - Pt(Gen) Pt(Charged Trk) - Pt(Gen) ATLAS日本総会@河口湖

  15. Np0=0, Np+-=3 • There is a possibility to use sum of charged tracks’ momentum as tau-jet’s momentum. Pt(Jet) - Pt(Gen) Pt(Charged Trks) - Pt(Gen) ATLAS日本総会@河口湖

  16. Number of Charged Tracks 50<Pt<70GeV 20<Pt<30GeV VBF No large dependence. Ntrk becomes smallin pileup events. QCD Ntrk ATLAS日本総会@河口湖

  17. Sum of Charge 50<Pt<70GeV 20<Pt<30GeV No large dependence. Qjet Pileup and noise don’t givea large effect oncharged track reconstruction. (track pt > 2GeV) ATLAS日本総会@河口湖

  18. Fraction of energy in DR<0.1 50<Pt<70GeV 20<Pt<30GeV • Jets become wider as increasing the effect of pileup. • Effect of noise seems to be small. • A fraction is slightly large at low F01. ATLAS日本総会@河口湖

  19. Performance of tauID (1) Rejection factor as a function ofefficiency. lumi00 • Much worse as expected. -> look them at each pt region. See next. lumi02 70<Pt<130 50<Pt<70 40<Pt<50 30<Pt<40 20<Pt<30 ATLAS日本総会@河口湖

  20. Performance of tauID (2) • Pileup gives a large effect onthe tauID performance. • Results of noise effect is similaras those of lumi01 not lumi00. ATLAS日本総会@河口湖

  21. Performance of tauID (3) • We can see clear decreases of tauID performance depending on the size of the pileup and noise. ATLAS日本総会@河口湖

  22. Mass（tautau） • Kyle（Wisconsin）のトラペより@2004年12月15日 • Et missingの理解不足->まだまだ研究が必要。 • Pileup等の影響も。 Central jet vetoなし ATLAS日本総会@河口湖

  23. 活動報告 ATLAS日本総会@河口湖

  24. Higgs WGのまとめ • Higgs WG meeting • 2004年（年度じゃなく） 8回 • 2日間の予定だったが、初回を除いてすべて1日のみの開催。 • 回数を増やした分、その間の進展が少なくなるのは当たり前 • 年間を通してWinconsinグループが半分程度のトークを維持。 • 活動 • VBF H->tt->hadron+lepton用のtauIDの研究 • 成果発表3回 • ATLAS-COM-PHYS-2004-069 • 10人程度でTau meetingをスタート（12月に初回）。 • Continuous Production for ROME@Higgs WG （予定） • 手は挙げた…が…。 ATLAS日本総会@河口湖

  25. SUSY WGのまとめ • SUSY WG meeting • 2004年 6回（phone meeting除く） • 活動 • お仕事（奉仕） • Btaggingの評価（not 開発） • DC2 Production Data for SUSY • 2回ほどSUSY WG meetingで報告した。 • Inclusive studyの開始（目的：兆候から発見へ） • 佐々木君が中心となって研究。 -> 今日のトーク • 12月のSUSY WG meetingで経過報告（by 浅井さん） ATLAS日本総会@河口湖

  26. 今後の予定 • ATLAS Physics WS@ローマ • 2005年6月7日-11日 • 物理本 : Readiness for Physics at ATLAS • 2006年 • Higgs • VBF H->tt->hadron+leptonの研究を維持 • tauID+tau jet calibration • 中村君（kojin、筑波）が参戦。 • Et missing（非常に重要） • VBF H->bb + W, WでBGを落とす。Yb測定にとって重要。 • VBF H->WW->lnjj • SUSY • Inclusive studyを継続。 • データベースを作る。（佐々木君） • 特定のポイントにおける詳細な研究 ATLAS日本総会@河口湖

  27. バックアップ ATLAS日本総会@河口湖

  28. Dataset • Pythia 6.2 (without Tauola) • All the samples were simulated by the DC1 scheme at the TOKYO PC farm. • No pileup • Reconstruction • ATHENA : ver 7.0.3 • Cone jet algorithm (R=0.4) • No noise VBF H->tt (mH=125) : ~100k QCD jets : ~20k ATLAS日本総会@河口湖

  29. Dataset • Pythia 6.2 (without Tauola) • All the samples were simulated by the DC1 scheme. • No pileup (lumi00) • Pileup : 1 x 10^33 (lumi01) • Pileup : 2 x 10^33 (lumi02) • Reconstruction • ATHENA : ver 7.0.3 • Cone jet algorithm (R=0.4), xKalman for charged tracks • Without noise for lumi00, lumi01, lumi02 • With noise for lumi00 (lumi00N) (mH=125GeV) lumi00 lumi01 lumi02 lumi00N ATLAS日本総会@河口湖

  30. 野本君の昨年のトラペ tau-lepton ・ mass 1.777GeV/c2 ・ life time 290.61×10-15 s ( cτ = 87.11μm ) Main tau decay mode Branching fraction τ- -> μ-νμντ 17.4 % e-νeντ 17.4 % (1prong) π-ντ 11.1 % π-π0ντ 25.4 % π-π0π0ντ 9.4 % (3prong) π-π+π-ντ 9.5 % π-π+π-π0ντ 4.4 % ATLAS日本総会@河口湖

  31. 野本君の昨年のトラペ VBF->tautau ・ VBFはgluon-fusionに比べて1桁くらい断面積が小さい。 ATLAS日本総会@河口湖

  32. 野本君の昨年のトラペ VBF->tautau ・ けれど、 - central jet veto 中央のrapidity gapにQjetがいるeventを捨てる。 - forward jet tagging Forward領域でhigh Pt jetが観測される。 　　という強力なevent-selectionによってきれいにイベントを取り出せる。 ATLAS日本総会@河口湖

  33. 野本君の昨年のトラペ VBF->tautau • tautauの特徴 - tauの崩壊でneutrinoが出てくるのに、Higgs massのreconstructが可能 ATLAS日本総会@河口湖

  34. EM σ/E=10%/SQRT(E) Fine: 0.025*0.025 第一段目のη：π/γ 角度分解能 50mrad/SqrtE ATLAS日本総会@河口湖

More Related