1 previously, when I calculated event selection efficiencies, I defined efficiencies as the following: efficiency in electron channel = (total number of selected events in electron channel / total number of generated events in the sample) efficiency in muon channel = (total number of selected events in muon channel / total number of generated events in the sample) now, since I can access the truth information, I know the exact numbers of events in electron channel and muon channel. the new efficiencies are defined as: efficiency in electron channel = (total number of selected events in electron channel / total number of electron events in the sample) efficiency in muon channel = (total number of selected events in muon channel / total number of muon events in the sample) W’  tb  Wbb  lnubb reconstructed event selection efficiency VS. reconstructed electron/muon P T cut electron channel muon channel

2 W’  tb  lnubb truth event selection efficiency VS. true electron/muon P T cut muon channel electron channel truth events are selected by: requiring an electron or a muon, a neutrino and 2 jets at truth level cuts for electrons: P T cut (variable on the x-axis), η cut: 0<|η|<1.37, 1.52<|η|< 2.47 cuts for muons: P T cut, |η| < 2.4 P T of neutrino > 25GeV transverse mass of W > 40GeV cuts for jets: P T > 20GeV, |η| < 4.5 at truth level, event selection efficiency increases with W’ mass.

3 W’  tb  Wbb  lnubb mass of truth W’ the following plots show the mass distributions of W’ at truth level the one on the left has linear y-axis, and the one on the right has y-axis in log scale for the samples with high W’ masses, they have long tails on the left of their peaks (extremely off-shell?) should I cut away the tails? e.g. for W’ mass = 2000GeV, should I ignore events that have W’ mass < 1750GeV and not to use them in my event selection efficiency calculations? linearlog

4 delta R distribution between truth W and truth top delta R distribution between truth electron and truth b coming from the top delta R distribution between truth muon and truth b coming from the top W’  tb  Wbb  lnubb delta R distributions at truth level

5 W’  tb  lnubb reconstructed event selection efficiency VS. delta R between truth lepton and truth b coming from top electron channelmuon channel the previous slide shows that, when W’ mass is very high, a lot of events have their electrons or muons being close to the b jets. so how is efficiency as a function of delta R? I calculate efficiencies from 10 different ranges of delta R: (1) dR<0.2, (2) 0.2<dR<0.4, (3) 0.4<dR<0.6, (4) 0.6<dR<0.8 (5) 0.8<dR<1.2, (6) 1.2<dR<1.6, (7) 1.6<dR<2.0 (8) 2.0<dR<2.5, (9) 2.5<dR<3.0, (10) 3.0<dR<4.0 I find out that all the events that have dR<0.2 are rejected. In the sample of W'mass=2000GeV, there are actually 84 electron events and 91 muon events that have dR<0.2, and all of them are rejected. The efficiency of 0.2<dR<0.4 is also significantly lower in electron channel W’ mass: 2000GeV