Studies of $b$-tagging performance and jet substructure in a high $p_\rm{T}$ $g\rightarrow b\bar{b}$ rich sample of large-$R$ jets from $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
This note summarizes studies of $b$-tagging performance and the modelling of jet properties in high $p_{\rm T}$, double $b$-tagged, large-$R$ jets from $\sqrt{s} = 8 TeV$ $pp$ collisions collected by the ATLAS detector at the Large Hadron Collider. The double $b$-tag requirement yields a sample rich in jets originating from the $g\rightarrow b\bar{b}$ process. Using this sample, the performance of $b$-tagging at small $b$-quark angular separations is probed, and the modeling of jet properties, including substructure variables, is examined. Good agreement between data and Monte Carlo simulation is found within the experimental uncertainties.
26 February 2016
Figures
Figure 01a
The Sd0 distributions for muon (left) and non-muon jets (right). The double flavor labels in the plots denote the flavor of the jet pair, with the muon jet given first.
png (127kB) pdf (23kB)
Figure 01b
The Sd0 distributions for muon (left) and non-muon jets (right). The double flavor labels in the plots denote the flavor of the jet pair, with the muon jet given first.
png (125kB) pdf (23kB)
Figure 02a
Sd0 distributions in data and simulation, after the simultaneous fit in bin of muon jet p T>150 GeV(left) and non-muon jet 50 GeV>p T>20 GeV (right). The flavor components shown include both combinations of flavors for the muon and non-muon matched jets. The green band indicates 1σ variation of flavor fraction fit.
png (104kB) pdf (20kB)
Figure 02b
Sd0 distributions in data and simulation, after the simultaneous fit in bin of muon jet p T>150 GeV(left) and non-muon jet 50 GeV>p T>20 GeV (right). The flavor components shown include both combinations of flavors for the muon and non-muon matched jets. The green band indicates 1σ variation of flavor fraction fit.
png (96kB) pdf (20kB)
Figure 03a
Sd0 distributions in data and simulation, after the simultaneous fit in bin of muon jet p T>150 GeV(left) and non-muon jet p T>80 GeV (right). The flavor components shown include both combinations of flavors for the muon and non muon matched jets. The green band indicates 1σ variation of flavor fraction fit.
png (101kB) pdf (20kB)
Figure 03b
Sd0 distributions in data and simulation, after the simultaneous fit in bin of muon jet p T>150 GeV(left) and non-muon jet p T>80 GeV (right). The flavor components shown include both combinations of flavors for the muon and non muon matched jets. The green band indicates 1σ variation of flavor fraction fit.
png (92kB) pdf (20kB)
Figure 04
Comparison of major flavor fractions predicted by MC simulation and the simultaneous fit to Sd0 distributions in data as a function of the large-R jet pT.
png (113kB) pdf (20kB)
Figure 05a
Δ R between the muon-jet and non-muon jet before (left) and after b-tagging (right). b-tagging scale factors and the flavor fraction correction have been applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (81kB) pdf (18kB)
Figure 05b
Δ R between the muon-jet and non-muon jet before (left) and after b-tagging (right). b-tagging scale factors and the flavor fraction correction have been applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (81kB) pdf (18kB)
Figure 06a
pT of the muon-jet (left) and non-muon jet (right) before (top) and after (bottom) b-tagging. b-tagging scale factors and the flavor fraction correction have been applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (44kB) pdf (17kB)
Figure 06b
pT of the muon-jet (left) and non-muon jet (right) before (top) and after (bottom) b-tagging. b-tagging scale factors and the flavor fraction correction have been applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (46kB) pdf (17kB)
Figure 06c
pT of the muon-jet (left) and non-muon jet (right) before (top) and after (bottom) b-tagging. b-tagging scale factors and the flavor fraction correction have been applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (51kB) pdf (17kB)
Figure 06d
pT of the muon-jet (left) and non-muon jet (right) before (top) and after (bottom) b-tagging. b-tagging scale factors and the flavor fraction correction have been applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (51kB) pdf (17kB)
Figure 07a
pT of the muon before (left) and after (right) b-tagging. b-tagging scale factors and the flavor fraction correction have been applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (48kB) pdf (18kB)
Figure 07b
pT of the muon before (left) and after (right) b-tagging. b-tagging scale factors and the flavor fraction correction have been applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (91kB) pdf (18kB)
Figure 08
Comparison of data and MC simulation double b-tagging rate as a function of the large-R jet pT. The error bars include statistical uncertainties, as well as the large-R jet energy scale uncertainty and b-tagging scale factor uncertainties.
png (98kB) pdf (19kB)
Figure 09a
The large-R jet pT (top) and mass (bottom), before (left) and after (right) b-tagging. The flavor fraction correction is applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet energy (top) or mass scale (bottom) and and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (97kB) pdf (19kB)
Figure 09b
The large-R jet pT (top) and mass (bottom), before (left) and after (right) b-tagging. The flavor fraction correction is applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet energy (top) or mass scale (bottom) and and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (103kB) pdf (20kB)
Figure 09c
The large-R jet pT (top) and mass (bottom), before (left) and after (right) b-tagging. The flavor fraction correction is applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet energy (top) or mass scale (bottom) and and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (98kB) pdf (19kB)
Figure 09d
The large-R jet pT (top) and mass (bottom), before (left) and after (right) b-tagging. The flavor fraction correction is applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet energy (top) or mass scale (bottom) and and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (97kB) pdf (19kB)
Figure 10a
The large-R jet D2(β=1) (top) and τ21wta (bottom), before (left) and after (right) b-tagging. The flavor fraction correction is applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES, the D2(β=1) (top) or the τ21wta (bottom) uncertainties and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (89kB) pdf (19kB)
Figure 10b
The large-R jet D2(β=1) (top) and τ21wta (bottom), before (left) and after (right) b-tagging. The flavor fraction correction is applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES, the D2(β=1) (top) or the τ21wta (bottom) uncertainties and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (95kB) pdf (19kB)
Figure 10c
The large-R jet D2(β=1) (top) and τ21wta (bottom), before (left) and after (right) b-tagging. The flavor fraction correction is applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES, the D2(β=1) (top) or the τ21wta (bottom) uncertainties and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (89kB) pdf (18kB)
Figure 10d
The large-R jet D2(β=1) (top) and τ21wta (bottom), before (left) and after (right) b-tagging. The flavor fraction correction is applied. The total systematic uncertainty, indicated by the hashed band, includes a 1σ variation on the b-tagging scale factor, the large-R jet JES, the D2(β=1) (top) or the τ21wta (bottom) uncertainties and the flavor fraction fit. The green band indicates 1σ variation of flavor fraction fit only.
png (88kB) pdf (18kB)
Figure 11a
The double ratio r trk Mass as a function of the large-R jet mass/pT for central (|η|<1.2, top) and forward (|η|>1.2, bottom) inclusive (left) and b-tagged (right) jets. In the top panel only statistical uncertainties are shown. In the bottom panel the error bars include the statistical uncertainty, the large-R jet JES and b-tagging uncertainties. The hashed area is the current large-R jet JMS uncertainty.
png (40kB) pdf (16kB)
Figure 11b
The double ratio r trk Mass as a function of the large-R jet mass/pT for central (|η|<1.2, top) and forward (|η|>1.2, bottom) inclusive (left) and b-tagged (right) jets. In the top panel only statistical uncertainties are shown. In the bottom panel the error bars include the statistical uncertainty, the large-R jet JES and b-tagging uncertainties. The hashed area is the current large-R jet JMS uncertainty.
png (40kB) pdf (16kB)
Figure 11c
The double ratio r trk Mass as a function of the large-R jet mass/pT for central (|η|<1.2, top) and forward (|η|>1.2, bottom) inclusive (left) and b-tagged (right) jets. In the top panel only statistical uncertainties are shown. In the bottom panel the error bars include the statistical uncertainty, the large-R jet JES and b-tagging uncertainties. The hashed area is the current large-R jet JMS uncertainty.
png (38kB) pdf (15kB)
Figure 11d
The double ratio r trk Mass as a function of the large-R jet mass/pT for central (|η|<1.2, top) and forward (|η|>1.2, bottom) inclusive (left) and b-tagged (right) jets. In the top panel only statistical uncertainties are shown. In the bottom panel the error bars include the statistical uncertainty, the large-R jet JES and b-tagging uncertainties. The hashed area is the current large-R jet JMS uncertainty.
png (38kB) pdf (15kB)
Figure 12a
The double ratio r trkp T as a function of the large-R jet pT for inclusive (left) and b-tagged (right) jets with |η|<2.0. In the top panel only statistical uncertainties are shown. In the bottom panel the error bars include the statistical uncertainty, the generator dependence and b-tagging uncertainties. The hashed area is the current large-R jet JES uncertainty.
png (40kB) pdf (16kB)
Figure 12b
The double ratio r trkp T as a function of the large-R jet pT for inclusive (left) and b-tagged (right) jets with |η|<2.0. In the top panel only statistical uncertainties are shown. In the bottom panel the error bars include the statistical uncertainty, the generator dependence and b-tagging uncertainties. The hashed area is the current large-R jet JES uncertainty.
png (40kB) pdf (16kB)
Figure 13a
The double ratio r trkD2(β=1) as a function of the large-R jet p T for inclusive (left) and b-tagged (right) jets with |η|<2.0. In the top panel only statistical uncertainties are shown. In the bottom panel the error bars include the statistical uncertainty, the large-R jet JES and b-tagging uncertainties. The hashed area is the current large-R jet D2(β=1) uncertainty.
png (38kB) pdf (16kB)
Figure 13b
The double ratio r trkD2(β=1) as a function of the large-R jet p T for inclusive (left) and b-tagged (right) jets with |η|<2.0. In the top panel only statistical uncertainties are shown. In the bottom panel the error bars include the statistical uncertainty, the large-R jet JES and b-tagging uncertainties. The hashed area is the current large-R jet D2(β=1) uncertainty.
png (38kB) pdf (16kB)
