Requirements for H-yy channel e Need good energy and angular resolution ATLAS to achieve 1-2%o resolution in the hig OcB=.7 GeV 120 GeV FWHM= 4.1 GeV mass reconstruction /m~14% e Need good particle identification 001 85% for real photon and reject the large mr[Gev) QCD background (o et al. )with ATLAS 1200 YY+DY Data Data 2012 r Data rejection above 1000. (9 EM shower 1of \5=8 TeV. Ldt=5.9fb -ij Data yap iarla b\es+ isolation are applied to ooF tug# Total uncertainty 600 separate reducible backgrounds 400 Purity:-70%*#4 种hh (r-jet,jet-jet) ;~-1-1-10-10 mrr[]
Requirements for H→gg channel Need good energy and angular resolution to achieve ~1-2% resolution in the Higgs mass reconstruction. σ/mH ~ 1.4% Need good particle identification : ~85% for real photon and reject the large QCD background (p0 et al.) with rejection above 1000. (9 EM shower shape variables+ isolation are applied to separate reducible backgrounds. (γ-jet,jet-jet). 16 Purity: ~70%
Energy Calibration and vertex correction <z→ ee peak> Energy calibration 8 180= ATLAS Pre e MC-based calibration Data 2011, \s=7 TeV, Ldt=4.6fb'1 5140=0176+0016e (experience from beam-test) u1200c=159±001GeV h<247 -+ Data o After that, energy scale correction Fit result 00040 □Z→e6MC obtained from electrons using Z ee events from data Vertex reconstruction 0.12T ATLAS Preliminary meGeⅥ (Simulation) 0. Unconverted photor 99→H→m:120Ge +6<μ≤9 1st+2nd layer em calorimeter Z +9<μ≤12 EM +μ>12 calorimeter Converted photon 0.02 1st layer em calorimeter 11411611 track from converted et/e- Beam axis 7 Robust against pileup(not use primary vertex 2/2/202
Energy Calibration and vertex correction Energy Calibration: MC-based calibration (experience from beam-test) After that, energy scale correction obtained from electrons using Z→ee events from data. Vertex reconstruction : Unconverted photon : 1 st+2nd layer EM calorimeter Converted photon : 1 st layer EM calorimeter + track from converted e+/e- 17 Robust against pileup (not use primary vertex) . 2/2/2021