Higgs Recoil Study ILC Physics meeting May 21, 2015 Jacqueline Yan 富山 12013/07/20.
LCWS2013 Higgs Recoil Mass Study at 350 GeV Apr 27, 2014 Jacqueline Yan Komamiya Lab, Univ. of Tokyo...
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Transcript of LCWS2013 Higgs Recoil Mass Study at 350 GeV Apr 27, 2014 Jacqueline Yan Komamiya Lab, Univ. of Tokyo...
![Page 1: LCWS2013 Higgs Recoil Mass Study at 350 GeV Apr 27, 2014 Jacqueline Yan Komamiya Lab, Univ. of Tokyo ILC@ 富山 12013/07/20.](https://reader035.fdocuments.in/reader035/viewer/2022081519/56649f275503460f94c3e5d3/html5/thumbnails/1.jpg)
LCWS2013
Higgs Recoil Mass Study at 350 GeV
Apr 27 , 2014
Jacqueline Yan Komamiya Lab, Univ. of Tokyo
ILC@ 富山 12013/07/20
![Page 2: LCWS2013 Higgs Recoil Mass Study at 350 GeV Apr 27, 2014 Jacqueline Yan Komamiya Lab, Univ. of Tokyo ILC@ 富山 12013/07/20.](https://reader035.fdocuments.in/reader035/viewer/2022081519/56649f275503460f94c3e5d3/html5/thumbnails/2.jpg)
What’s New This Week
improve (correct) fitting method re-evaluate data selection performance and cross section error
Compare alternative polarization scenarios
Comparison with sqrt(s)=250 GeV Summary & Plans
Goal: precise measurement of • Higgs mass
• cross section σH
recoil mass study using e+e- recoil mass study using e+e- Zh Zh μ+μ-h μ+μ-h
Ec.m.s. = 250 GeV, L = 250 fb-1Ec.m.s. = 350 GeV, L = 333 fb-1Ec.m.s. = 350 GeV, L = 333 fb-1
polarization: (e-, e+) = (- 0.8, + 0.3)
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Signal sample: Pe2e2h_.eL.pR & Pe2e2h._eR.pL
relevant BG process for Zmumu• 4f_ZZ_leptonic• 4f_ZZ_semileptonic• 2f_Z_leptonic• 4f_WW_leptonic• 4f_WW_semileptonic• 4fSingleZee_leptonic• 4fSingleZnunu_leptonic• 4f_ZZWWMix_leptonic• 6f backgrounds (sqrt(s)=350 GeV)
after all cuts, dominant BG are: sqrt(s) = 250 GeV : #1) 2f_Z_l #2) 4f_ZZ_sl #3) 4f_ZZWWMix_l
sqrt(s) = 350 GeV : #1) 4f_ZZ_sl #2) 2f_Z_l #3) 4f_WW_sl no ttbar BG left after data selection
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Δσ/σ ~ 4.1 %
fitted recoil mass : Mh =125.7 GeV +/- 144 MeV
recoil mass
calculated recoil mass with correction for 14 mrad beam crossing angle
BG: 3rd order polynomial signal : GPET: 5 parameters :
Gaus (left-side) , Gaus + expo (right side)
Final fitting: float only height and mean, fix others from BG shape and 1st time fitting
1st time: fit only signal float all 5 GPET pars
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Final Selection for 350 GeV • 84 GeV < M_mumu < 98 GeV • 10 GeV < pT_mumu < 140 GeV• coplanarity < 3• |cos(θ_Zpro)| < 0.91 (Z production angle)• 120 GeV < Mrecoil < 140 GeV
Muon Selection •reject neutrals • Ptot > 5 GeV• small E_cluster / P_total < 0.5• opposite charge Best track selection : cos(track angle) < 0.98 & |D0/δD0| < 5
Best Z Candidate Selection 2 mu candidates with opposite chargechoose pair with invariant mass closest to Z mass
Evaluate performance in recoil mass range of 120– 140 GeV
calculate recoil mass with correction for 14 mrad beam crossing angle
![Page 6: LCWS2013 Higgs Recoil Mass Study at 350 GeV Apr 27, 2014 Jacqueline Yan Komamiya Lab, Univ. of Tokyo ILC@ 富山 12013/07/20.](https://reader035.fdocuments.in/reader035/viewer/2022081519/56649f275503460f94c3e5d3/html5/thumbnails/6.jpg)
Sig + BG
fitting using weighted binsFitting in wide range 115-150 GeV
Sig + BG
Integrated fitted func in (120 – 140 GeV)
error : 3.15/76.67 = 4.1 % Nsig = 1080+/-44 <ε> = 48.9 +/- 0.5 %
Nbg= 3467S/BG = 0.32 significance = 16.2
Very close to result from just counting under histogram
•<Nsig = 1089+/-45 •<ε> = 48.9 +/- 0.5 %•S/BG = 0.31• significance = 16.1
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Compare Alternative Polarization Scenarios
See supplementary EXCEL files (attached to meeting page)
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Comparisons (0,0) seems best for both Δσ/σ(+0.8, -0.3) yields best S/N , Δσ/σ not bad eitherWW BGs significantly suppressed (< 1/10 of (-0.8, *0.3)) other major BGs less also (esp for eLpR) (< ½ of (-0.8, +0.3) even though statistics is lower, some BG process is suppressed ? no big difference between (-0.8, + 0.3) and (-0.8, 0) no big difference in cut efficiency for each individual BG process is e+ polarization really necessary (practical)? Re-consider for 250 GeV (accelerator issues)
ε Δσ/σ Nsig S/N significance350 GeV
(-0.8,+0.3) 48.9+/-0.5% 4.10% 1089+/-45 0.31 16.1
(-0.8,0) 47.6+/-0.5% 4.00% 865+/-34 0.32 14.4
(0,0) 47.7+/-0.5% 3.10% 737+/-23 0.37 14.1
(+0.8,-0.3) 47.8+/-0.5% 3.70% 738+/-27 0.48 15.4
250 GeV
(-0.8,+0.3) 69.9+/-0.5% 4.10% 1752+/-72 0.26 19
(-0.8,0) 67.2+/-0.5% 4.00% 1390+/-56 0.26 17
(0,0) 66.9+/-0.5% 3.20% 1183+/-38 0.3 16.6
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350 GeV (-0.8, + 0.3)(-0.8, 0)
(0 , 0)(+0.8, -0.3)
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Compare with Results for 250 GeV
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250 GeV (-0.8, + 0.3)
(0, 0)
(-0.8, 0)
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Δσ/σ ~ 4.1 %
fitted recoil mass : Mh =125.6 GeV +/- 144 MeV
recoil mass
calculated recoil mass with correction for 14 mrad beam crossing angle
BG: 3rd order polynomial signal : GPET: 5 parameters :
Gaus (left-side) , Gaus + expo (right side)
Final fitting: float only height and mean, fix others from BG shape and 1st time fitting
1st time: fit only signal float all 5 GPET pars
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Final Selection for 250 GeV analysis after filling root files
• 84 GeV < M_mumu < 98 GeV • 10 GeV < pT_mumu < 70 GeV• |cos(θ_Zpro)| < 0.91 (Z production angle)• 120 GeV < Mrecoil < 140 GeV• also tried 123 GeV – 135 GeV
Muon Selection •reject neutrals • Ptot > 5 GeV• small E_cluster / P_total < 0.5• opposite charge Best track selection cos(track angle) < 0.98 |D0/δD0| < 5
Best Z Candidate Selection 2 mu candidates with opposite charge if several possibilities : choose pair with invariant mass closest to Z mass
Evaluate data selection efficiency in within range of 120– 140 GeV
calculate recoil mass with correction for 14 mrad beam crossing angle
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optimization of data selection method for Higgs recoil mass study using e+e- Zh μ+μ-h @ Ec.m.s =350 GeV, L = 333 fb-1
• compared with @ Ec.m.s. = 250 GeV, L = 250 fb-1
•350 GeV: • ε_sig = 48,9 +/-0.5 %, S/B ~ 0.31, significance ~ 16.1 Δσmeas> / <σmeas> = 4.1 % • fitted recoil mass : 125.7 GeV +/- 144 MeV
250 GeV: • ε_sig = 69.9 +/-0.5 %, S/B ~ 0.26, significance ~ 19 Δσmeas> / <σmeas> = 4.1 % fitted recoil mass : 125.4 GeV +/- 44 MeV
• After improvement of fitting, efficiency and Δσ/σ seem much improved
Compared different polarization scenarios : (-0.8, 0.3) vs (+ 0.8, -0.3) vs (0 ,0)• (0,0) is best for Δσ/σ , not realistic (?)• (+0.8, -0.3) seems to have better S/N (?), but not practical (?)• not much difference between (-0.8,0) amd (-0.8, +0.3) •Need to balance physics merits with accelerator (e+ production) issues
Summary
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Use Toy MC to evaluate cross section error may resolve some statistical fluctuations
Deeper study of which process is suppressed by alternative polarization scenarios
improve data selection Implement Pt_bal and likelihood cut ?
Plans
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BACKUP
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• preliminary comparison of cut efficiency between MC truth and reconstructed for 350 GeV signal and a few dominant BGs : integrated under histograms, counted in region 123-135 GeV
Rec cut signal eff 4f_ZZ_sl eff 2f_Z_l effraw 2288 100% 188087 100.00% 2226361 100.00%only best mu pair 2214 97% 25217 13.41% 329581 14.80%cos(trackAng)<0.98 2202 96% 19906 10.58% 305146 13.71%84 <M_inv <98 1824 80% 5314 2.83% 94671 4.25%10 <P_Tdl<140 1817 79% 5198 2.76% 26063 1.17%copl < 3 1790 78% 4853 2.58% 22766 1.02%cos(θZ)<0.91 1707 75% 3672 1.95% 10765 0.48%120 GeV <M_rec <140 GeV 1089 48% 1133 0.60% 1050 0.05%MC cut signal eff 4f_ZZ_sl eff 2f_Z_l effraw 2288 100% 188087 100.00% 2226361 100.00%only best mu pair 2288 100% 26219 13.94% 417982 18.77%cos(trackAng)<0.98 2208 97% 17385 9.24% 306297 13.76%84 <M_inv <98 1981 87% 5115 2.72% 102691 4.61%10 <P_Tdl<140 1945 85% 5006 2.66% 24539 1.10%copl < 3 1945 85% 4691 2.49% 24539 1.10%cos(θZ)<0.91 1852 81% 3599 1.91% 11813 0.53%120 GeV <M_rec <140 GeV 1256 55% 1056 0.56% 986 0.04%
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MC
reconstructed
Black : muon-Green: muon +
Muon track angle sqrt(s) = 350 GeV
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more forward/ asymmetrical than 350 GeV
MC
reconstructed
Black : muon-Green: muon +
Muon track angle sqrt(s) = 250 GeV
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(0, 0)(+0.8, -0.3)
(-0.8, + 0.3)(-0.8, 0)
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recoil mass cut 120-140 GeVfit in 114-140 GeV<n> = 1115 +/- 46<ε> = 42.8 +/- 1.7 %
<n>/sqrt(<n>+<B>) = 14.7<n>/<B>=0.24
Δσmeas> / <σmeas> = 4.1 %
250 GeV
Compare 250 GeV & 350 GeV: integrate fitted functions
Calculate Error of σmeas from relative error of height fitting
recoil mass cut 120-140 GeVfit in 115 – 150 GeV<n> = 1145 +/- 54<ε> = 51.4 +/- 2.4 %
<n>/sqrt(<n>+<B>) = 17.3<n>/<B>=0.35
Δσmeas> / <σmeas> = 4.7 %
350 GeV
recoil mass cut : 123 – 135 GeVfit in 114-140 GeV<n> = 1169 +/- 48<ε> = 44.9+/- 1.8 %
<n>/sqrt(<n>+<B>) = 18.5<n>/<B>=0.42
Δσmeas> / <σmeas> = 4.1 %
recoil mass cut 120-140 GeVfit in 114-140 GeV<n> = 1115 +/- 50<ε> = 50.1 +/- 2.2 %
<n>/sqrt(<n>+<B>) = 17.2<n>/<B>=0.36
Δσmeas> / <σmeas> = 4.5 %
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Compare different polarization scenarios
sqrt(s) = 350 GeV L = 333 fb-1
For now, keep same cut parameters as (-0.8, +0.3) (they could be optimized)
(0, 0)Pol weight(eLpR) = 0.5*0.5Pol weight(eRpL) = 0.5*0.5
<n> = 737 +/- 23<ε> = 33.1+/- 1.0 %
<n>/sqrt(<n>+<B>) = 14.2<n>/<B>=0.37
Δσmeas> / <σmeas> = 3.1 %
(+0.8, -0.3) Pol weight(eLpR) = 0.1*0.35Pol weight(eRpL) = 0.9*0.65
n> = 737 +/- 27<ε> = 33.1+/- 1.2 %
<n>/sqrt(<n>+<B>) = 15.8<n>/<B>=0.51
Δσmeas> / <σmeas> = 3.7 %
(-0.8, + 0.3)Pol weight(eLpR) = 0.9*0.65Pol weight(eRpL) = 0.1*0.35
<n> = 1080 +/- 44<ε> = 48.5 +/- 2.0 %
<n>/sqrt(<n>+<B>) = 16.2<n>/<B>=0.32
Δσmeas> / <σmeas> = 4.1 %
(-0.8, 0)Pol weight(eLpR) = 0.9*0.5Pol weight(eRpL) = 0.1*0.5
<n> = 857 +/- 34<ε> = 38.5+/- 1.5 %
<n>/sqrt(<n>+<B>) = 14.5<n>/<B>=0.32
Δσmeas> / <σmeas> = 4.0 %
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Signal efficiency 61 % S/N 0.39 Significance 〜 21.2
Evaluation in 123 – 135 GeV region sqrt(s) = 250 GeV count under histograms
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DBD Samplesevent weight = pol_weight * ( process_cross_section * assumed_integrated_luminosity )/ ( number_of_reconstructed_events )
sqrt(s) = 250 GeV/grid/ilc/prod/ilc/mc-dbd/ild/dst-merged/250-TDR_ws/
20 x Higher statistics data : /hsm/ilc/grid/storm/user/a/amiyamot/myprod/ild/dst-merged /250-TDR_ws/reference: meta files and diagrams in http://ilcsoft.desy.de/dbd/generated/other.html
sqrt(s) = 350 GeV/grid/ilc/prod/ilc/mc-dbd/ild/dst-merged/350-TDR_ws/List of samples: http://www-jlc.kek.jp/~miyamoto/CDS/prod_status/REC_ILD_o1_v05_350GeV.html
LumosityTDR baselinesqrt(s)=250 GeV, Lumi=0.75 x 10^34 cm^-2 s^-1 assume L = 250 fb-1sqrt(s)=350 GeV, Lumi=1.0 x 10^34 cm^-2 s^-1 assume L = 333 fb-1
Polarization: (-0.8, + 0.3) compare with (+0.8, -0.3)
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stacked, eLpR
stacked, eRpL
250 GeV
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recoil mass
after implementing all cuts
Black : MC
Red: reconstructed
pT
Invariant mass
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Black : MC
Red: reconstructed
Z production angle
coplanarity
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dilepton PT, 350 GeV
do cut : 10 GeV< pT_dl < 140 GeV
Signal , 250 GeV: 0 – 80 GeV peak at about 60 GeV
Before cuts)
Signal , 350 GeV: 0 – 140 GeV peak at about 135 GeV
Before cuts)