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Tracking Efficiency of higgs to bb. Pooja Saxena CDRST Delhi University, INDIA. Outline. Definitions & selection cut Results at 3TeV center of mass energy. e + e - -> bb~nunu ~ e + e - -> bb~. Definitions & Selection cut. Tracking Efficiency:
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Tracking Efficiency of higgs to bb Pooja Saxena CDRST Delhi University, INDIA
Outline • Definitions & selection cut • Results at 3TeV center of mass energy • e+e- -> bb~nunu~ • e+e- -> bb~
Definitions & Selection cut Tracking Efficiency: = reconstructed MC particles / MC particles where, - reconstructed MC particle: tracks which could match with the MC particles. - MC particles: All findable MC particle from the generated level. Common cuts • Theta cut: 10 < θ< 170 (deg) • Pt cut: pt > 1GeV • |Origin- vertex point| < 50 mm • Charge: Different from 0 • Flight distance cut: path length> 10 mm
Tracking EfficiencyResults: e+e- -> bb~vv~ at 3 TeV~9k events 95.9%
Efficiency plots (All MC particles) 98% 94% 100% • Efficiency ~98% in the central region, and falls to ~ 94% in the very forward region. • Efficiency drops with increase in Pt • For hits ≥ 8, efficiency is ~100 % (except for hit=19)
Efficiency plots:(stable MC particles) 99% 99% 98% Transition from barrel to disk 100% 98.7% • Stable at the generator level
Efficiency plots:(backscattered) 90% 80% 80% 80% • Backscattered are in the pt range of 1-10 GeV
Efficiency plots:(unstable MC particles) 80% 60% 95% 66% • Efficiency ~80% in the central region, and falls to ~ 60% in the vary forward region. • Efficiency very low for low pt (1-5 GeV) particles &further drops with increase in Pt • For hits ≥ 8, efficiency is ~100 % (except hit=18)
Pt distribution: ee -> bbuu Stable all mc Unstable Backscattered
No of Hits(All MC) • hits ≥ 6 99.5% 99.7% 96.2% • hits < 6 3.7% no of hits < 6 MC is reconstructed too but less efficiently
Non reco MC (4.1 % fraction of all MC) 40cm 6 • 0.5% fraction of all MC with high path length(>40cm) & high pt(>1GeV) could not be reconstructed. • Out of 0.5%, 18% lies in central region whereas 81.9% in forward region. • Majority of them were high pt π & few K, p, e, µ & D. 6 • Majority of High Pt particles giving low hits are the B, D mesons which decays sooner or later in the tracker
MC (hits>14) [19% fraction of all MC] • Central region • Forward Region • 19% fraction of all MC particles are lying in hits>14 (22014 MC particles) • Out of 19%, ~99.9% lies in forward region & ~0.07% in central region • In central region, they all are low pt, low pz e-. • Trying to resolve, why high pt, high pz particles giving hits>14.
Stable non RECO MC (1% of all MC) 40cm 6 • 1.0 % of all MC particles are stable non reco • ~30 % of the non reco MC are the stable non reco particles. • π+- , k, p are the unreconstructed stable particles • Stable at the Generator level
Stable non RECO MC 1% of all MC π+- p K • 1.0 % of all MC particles are stable non reco • ~30 % of the non reco MC. • π+- , k, p are the unreconstructed stable particles
B Meson (6.8% fraction of all MC ) Pt >1 GeV Pt >1 GeV Pt distribution theta distribution Pt >1 GeV Pt >1 GeV Pt distribution (Path length >10 mm) • All (7832) were produced from the IP with high pt(>1GeV). • Out of 6.8%, ~ 0.8% (834) lies in the beam pipe whereas rest 99.2 % (6998) in theta region of 10<θ <170 degree. • In theta acceptance, 30 % goes to central region & rest 70% to forward region.
Summary • For ee->bbuu at 3 TeV COM energy, track reconstruction efficiency is found to be 95.9% on all MC level & 98.7% at the stable MC level. • MC particles having high pt & high pz giving hits>14 is still to look for.
Tracking EfficiencyResults: e+e-->γ*/Z -> bb~ at 3 TeV~9k events 96%
Efficiency plots 98% 94% ?
Efficiency plots:MC status = 0 (backscattered) 80% 80% 77.4%
Efficiency plots:MC status = 1 (stable MC) 98% 99% 98% 98.6%
Efficiency plots:MC status = 2 (unstable MC) 80% 66.5% 70.7%
Pt distribution: ee -> bb Stable all mc Unstable Backscattered
No of Hits(All MC) • hits ≥ 6 99.5% 99.5% 96.7% • hits < 6 3.4% no of hits < 6 MC is reconstructed too but less efficiently
Non reco MC (3.8 % fraction of all MC) 6 40cm • 0.6% fraction of all MC with high path length(>40cm) & high pt(>1GeV) could not be reconstructed. • Out of 0.6%, 14% lies in central region whereas 86% in forward region. • Majority of High Pt particles giving low hits are the B, D mesons which decays sooner or later in the tracker
MC (hits>14) [20% fraction of all MC] Central region Forward Region • 20% fraction of all MC particles are lying in hits>14 (22014 MC particles) • Out of 20%, ~99.9% lies in forward region & ~0.07% in central region • In central region, all are low pt low pz e-
Summary • For ee->bbuu at 3 TeV COM energy, track reconstruction efficiency is found to be 95.9% on all MC level & 98.7% at the stable MC level. • For ee->bb at 3 TeV COM energy, track reconstruction efficiency is 96% on all MC level & 98.6% at the stable MC level. • MC particles having high pt & high pz giving hits>14 is still to look for.
Pt distribution: ee -> bbuu Status=0 all mc Status=2 Status=1
Pt distribution: ee -> bb Status=0 all mc Status=2 Status=1
MC (10<hits<20) p π+- K, D • 46% fraction of all MC particles are lying in 10<hits<20 (#52994) • 99% lies in forward region & 1% in central region
Non Reco Status=1 mc particles Lakdfjkd Dfa Dfdf Dfa 20% Central region-> Lakdfjkd Dfa Dfdf Dfa (of status=1 non reco particles)
Efficiency plots pt>20GeV: forward region 80% 55% • Efficiency falls from 80% from forward to 55 from vary forward region.
Efficiency plots pt>20GeV central region 90% 85% Low statistics for high pt
Efficiency plots (pt < 200GeV) 98% 94% 100%
Tracking EfficiencyResults: e+e-->γ -> bb at 3 TeV~9k events
Efficiency plots pt>20GeV central region • pt< 200 GeV
Efficiency plots pt>20GeV forward region • pt< 200 GeV
