Additional Plots showing the top-quark content of the excess
We study the excess seen in the multijet analysis at jet-triplet mass of 175 GeV/c^2. The plots shown below are, from left to right:
- The jet-triplet mass with stated diagonal and jet-pt cuts (nominal 3-jet mass plot)
- The nominal 3-jet mass plot with the added requirement of at least one b-tagged jet somewhere in the event.
- The nominal 3-jet mass plot with the added requirement of one and only one b-tagged jet within the triplet.
- Dijet mass of the two non-b-tagged jets in the triplet from the previous plot (only one btag in triplet), with the added requirement that the triplet mass be in the top-mass window: 153 GeV/c^2 < 3-jet mass < 189 GeV/c^2. If the excess is indeed due to a top quark, a resonance at the W-mass should be visible.
We perform this study for the data sample used in the RPV gluino search, (3.2 fb^-1, multijet trigger), as well as a larger dataset with the following changes:
- Jet-100 trigger (A jet > 100 GeV at trigger level)
- 4 or more jets (the gluino analysis required 6 or more)
- 5.9 fb^-1 of data (the gluino analysis had 3.2 fb^-1)
- We increased the Jet-pt requirement from nominal of 15 GeV, to 20 GeV, and then 23 GeV for the last set.
- We increased the diagonal cut from a nominal of 190 GeV to 195 GeV for the last set.
Note that for the nominal 3.2 fb^-1 plots, the excess consistent with the mass of the top remains after requiring a b-tag in the event. However, statistics for the only-one btag sample are poor. For the 5.9 fb^-1 plots, we see a dijet peak consistent with the mass of the W for triplets consistent with the top. The final set of plots, with harder diagonal cut and jet-pt cuts, is especially clear.
We count the number of triplets where
- the 3-jet mass lies within the top window described above,
- the triplet has only one b-tagged jet,
- the invariant mass of the two non-b-tagged jets lies within 10 GeV/c^2 of the W mass. We indicate the number of events seen in data and expected in Pythia ttbar simulation in red .
Plots with 3.2 fb^-1, Multijet trigger, Diagonal Cut 190 GeV, Jet Pt cut 15 GeV/c
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3-jet Mass EPS or GIF. | 3-jet Mass with b-tag in the event EPS or GIF. | 3-jet Mass with exactly one b-tag in triplet EPS or GIF. | Dijet Mass of non-btag-jets in 3rd plot for M_jjj in top-mass window EPS or GIF. Events in top and W-mass windows: 0 seen in data 0.43 Expected from Pythia |
Plots with 5.9 fb^-1, Jet-100 trigger, Diagonal Cut 190 GeV, Jet Pt cut 20 GeV/c
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3-jet Mass EPS or GIF. | 3-jet Mass with b-tag in the event EPS or GIF. | 3-jet Mass with exactly one b-tag in triplet EPS or GIF. | Dijet Mass of non-btag-jets in 3rd plot for M_jjj in top-mass window EPS or GIF. Events in top and W-mass windows: 13 seen in data 2.1 Expected from Pythia |
Plots with 5.9 fb^-1, Jet-100 trigger, Diagonal Cut 195 GeV, Jet Pt cut 23 GeV/c
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3-jet Mass EPS or GIF. | 3-jet Mass with b-tag in the event EPS or GIF. | 3-jet Mass with exactly one b-tag in triplet EPS or GIF. | Dijet Mass of non-btag-jets in 3rd plot for M_jjj in top-mass window EPS or GIF. Events in top and W-mass windows: 9 seen in data 1.6 Expected from Pythia |
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