|
< < | - TTbar samples
Sample |
A (0.2<R<0.4, <2 top) |
B (R>0.4, <2 top) |
C (0.2<R<0.4, 2 top) |
D = B*C/A pred. |
D (R>0.4, 2 top) obs. |
Ratio pred./obs. |
Pull (pred-obs)/error |
KS test |
TTJetsHT600 |
25.18 +- 0.16 |
2.09 +- 0.05 |
12.49 +- 0.11 |
1.04 +- 0.03 |
0.82 +- 0.03 |
1.27 +- 0.05 |
5.70 |
0.00 |
-> All Bkg. |
399.23 +- 13.06 |
9.45 +- 1.01 |
85.58 +- 5.61 |
2.03 +- 0.26 |
2.10 +- 0.18 |
0.97 +- 0.15 |
-0.22 |
0.00 |
TTHerwig |
34.09 +- 1.90 |
2.43 +- 0.51 |
25.33 +- 1.63 |
1.80 +- 0.41 |
1.37 +- 0.38 |
1.31 +- 0.47 |
0.78 |
0.69 |
-> All Bkg. |
408.13 +- 13.20 |
9.79 +- 1.13 |
98.41 +- 5.85 |
2.36 +- 0.32 |
2.65 +- 0.42 |
0.89 +- 0.18 |
-0.55 |
0.00 |
TTPowhegPythia6 |
27.98 +- 1.77 |
1.80 +- 0.45 |
17.53 +- 1.40 |
1.13 +- 0.30 |
0.67 +- 0.28 |
1.67 +- 0.82 |
1.10 |
0.57 |
-> All Bkg. |
402.02 +- 13.18 |
9.16 +- 1.11 |
90.61 +- 5.79 |
2.06 +- 0.29 |
1.95 +- 0.33 |
1.06 +- 0.23 |
0.25 |
0.00 |
TTPowhegPythia8 |
41.90 +- 2.09 |
3.97 +- 0.64 |
23.09 +- 1.55 |
2.19 +- 0.40 |
1.25 +- 0.36 |
1.75 +- 0.60 |
1.73 |
0.27 |
-> All Bkg. |
415.95 +- 13.23 |
11.33 +- 1.20 |
96.18 +- 5.82 |
2.62 +- 0.33 |
2.53 +- 0.40 |
1.03 +- 0.21 |
0.17 |
0.00 |
TTJetsNLO |
54.79 +- 1.63 |
4.14 +- 0.45 |
32.94 +- 1.27 |
2.49 +- 0.30 |
1.80 +- 0.30 |
1.38 +- 0.28 |
1.64 |
0.00 |
-> All Bkg. |
428.84 +- 13.16 |
11.50 +- 1.11 |
106.03 +- 5.75 |
2.84 +- 0.33 |
3.08 +- 0.35 |
0.92 +- 0.15 |
-0.50 |
0.00 |
TTNLO |
88.22 +- 3.12 |
6.40 +- 0.84 |
51.78 +- 2.39 |
3.76 +- 0.54 |
2.54 +- 0.53 |
1.48 +- 0.37 |
1.61 |
0.00 |
-> All Bkg. |
462.27 +- 13.43 |
13.77 +- 1.32 |
124.87 +- 6.10 |
3.72 +- 0.41 |
3.82 +- 0.56 |
0.97 +- 0.18 |
-0.14 |
0.00 |
- Use AK4 jets for R, a'la Razor recipe |
> > | 1) Use AK4 jets for R, a'la Razor recipe |
|
Used Old JEC MC samples
|
|
(I will also do a tt-pair R vs AK8 R comparison which might be useful) |
|
< < | - Try shrinking R control region from [0,0.4] to [~0.3,0.4] |
> > | 2) Try shrinking R control region from [0,0.4] to [~0.3,0.4] |
|
R sideband: [0,0.4]
|
|
This works! The TTbar prediction is closer to the actual values. I used [0.2, 0.4] bin so the statistical precision doesn't decrease, we need to have a little bit of compromise here to keep statistical error low but also having a better TTbar estimate. Signal contamination is also less in this bin. |
|
< < | - Show yields for all 8 boxes defined by 3-axis: R, Ntop, DPhi |
> > | 3) How would we treat signal pollution ?
Show yields for all 8 boxes defined by 3-axis: R, Ntop, DPhi |
|
R sideband: [0.2,0.4] - DPhi>2.7 |
|
< < |
|
> > |
|
|
TTJetsHT600 |
52.76 +- 0.24 |
1.81 +- 0.04 |
23.89 +- 0.16 |
0.82 +- 0.02 |
0.83 +- 0.03 |
0.99 +- 0.04 |
-0.23 |
0.00 |
WJets |
63.94 +- 0.80 |
1.87 +- 0.14 |
16.39 +- 0.41 |
0.48 +- 0.04 |
0.55 +- 0.08 |
0.87 +- 0.14 |
-0.80 |
0.00 |
ZJetsToNuNu |
10.56 +- 0.33 |
0.46 +- 0.07 |
2.10 +- 0.15 |
0.09 +- 0.02 |
0.09 +- 0.03 |
0.97 +- 0.36 |
-0.07 |
1.00 |
|
|
Diboson |
3.01 +- 0.30 |
0.14 +- 0.06 |
1.08 +- 0.19 |
0.05 +- 0.02 |
0.04 +- 0.02 |
1.30 +- 0.79 |
0.41 |
0.71 |
Sum Bkg. |
5795.61 +- 66.01 |
12.24 +- 1.35 |
1265.66 +- 31.87 |
3.33 +- 0.09 |
3.84 +- 0.81 |
0.87 +- 0.18 |
-0.62 |
- |
All Bkg. |
5795.61 +- 66.01 |
12.24 +- 1.35 |
1265.66 +- 31.87 |
2.67 +- 0.30 |
3.84 +- 0.81 |
0.70 +- 0.17 |
-1.35 |
0.00 |
|
|
< < |
Combined Bkg. |
|
|
|
3.45 +- 0.09 |
5.10 +- 0.66 |
0.68 +- 0.09 |
-2.48 |
- |
|
|
T5ttttDeg _mGo1000_4bodydec |
5.90 +- 0.32 |
1.12 +- 0.14 |
7.69 +- 0.36 |
1.47 +- 0.21 |
1.24 +- 0.15 |
1.18 +- 0.22 |
0.86 |
0.79 |
|
|
> > | In |Dphi|<2.7, signal pollution is:
A: ~1%
B: 120%
C: ~6%
In |DPhi|>2.7, the signal pollution is one order of magnitude smaller!
A': 0.1%
B': 9%
C~: 0.6%
A'/C' ratio is very similar to the A/C ratio, we can substitute that instead.
The B/B' background ratio could be taken from MC and use it to scale the number of events in B' to have an order of magnitude less polluted estimate for B and then D).
D is then: D = (B/B')_MC * B' * C' / A' = (9.45/12.24) * 13.36 * 1273.35 / 5801.51 = 2.26
c.f: 2.10 with no signal contamination. The error then is around the signal pollution level of B' which can also be substracted maybe, but it's definitaley lower than ABCD only prediction.
i.e: Polluted A/B/C would cause:
D_poll = B_poll * C_poll / A_poll = 4.67
--> This would be much larger and therefore it is a legitimate question
This method I think looks good! Is this the logic you described, Petar?
4) Try other TTbar samples as a comparison
Sample |
A (0.2<R<0.4, <2 top) |
B (R>0.4, <2 top) |
C (0.2<R<0.4, 2 top) |
D = B*C/A pred. |
D (R>0.4, 2 top) obs. |
Ratio pred./obs. |
Pull (pred-obs)/error |
KS test |
TTJetsHT600 |
25.18 +- 0.16 |
2.09 +- 0.05 |
12.49 +- 0.11 |
1.04 +- 0.03 |
0.82 +- 0.03 |
1.27 +- 0.05 |
5.70 |
0.00 |
-> All Bkg. |
399.23 +- 13.06 |
9.45 +- 1.01 |
85.58 +- 5.61 |
2.03 +- 0.26 |
2.10 +- 0.18 |
0.97 +- 0.15 |
-0.22 |
0.00 |
TTHerwig |
34.09 +- 1.90 |
2.43 +- 0.51 |
25.33 +- 1.63 |
1.80 +- 0.41 |
1.37 +- 0.38 |
1.31 +- 0.47 |
0.78 |
0.69 |
-> All Bkg. |
408.13 +- 13.20 |
9.79 +- 1.13 |
98.41 +- 5.85 |
2.36 +- 0.32 |
2.65 +- 0.42 |
0.89 +- 0.18 |
-0.55 |
0.00 |
TTPowhegPythia6 |
27.98 +- 1.77 |
1.80 +- 0.45 |
17.53 +- 1.40 |
1.13 +- 0.30 |
0.67 +- 0.28 |
1.67 +- 0.82 |
1.10 |
0.57 |
-> All Bkg. |
402.02 +- 13.18 |
9.16 +- 1.11 |
90.61 +- 5.79 |
2.06 +- 0.29 |
1.95 +- 0.33 |
1.06 +- 0.23 |
0.25 |
0.00 |
TTPowhegPythia8 |
41.90 +- 2.09 |
3.97 +- 0.64 |
23.09 +- 1.55 |
2.19 +- 0.40 |
1.25 +- 0.36 |
1.75 +- 0.60 |
1.73 |
0.27 |
-> All Bkg. |
415.95 +- 13.23 |
11.33 +- 1.20 |
96.18 +- 5.82 |
2.62 +- 0.33 |
2.53 +- 0.40 |
1.03 +- 0.21 |
0.17 |
0.00 |
TTJetsNLO |
54.79 +- 1.63 |
4.14 +- 0.45 |
32.94 +- 1.27 |
2.49 +- 0.30 |
1.80 +- 0.30 |
1.38 +- 0.28 |
1.64 |
0.00 |
-> All Bkg. |
428.84 +- 13.16 |
11.50 +- 1.11 |
106.03 +- 5.75 |
2.84 +- 0.33 |
3.08 +- 0.35 |
0.92 +- 0.15 |
-0.50 |
0.00 |
TTNLO |
88.22 +- 3.12 |
6.40 +- 0.84 |
51.78 +- 2.39 |
3.76 +- 0.54 |
2.54 +- 0.53 |
1.48 +- 0.37 |
1.61 |
0.00 |
-> All Bkg. |
462.27 +- 13.43 |
13.77 +- 1.32 |
124.87 +- 6.10 |
3.72 +- 0.41 |
3.82 +- 0.56 |
0.97 +- 0.18 |
-0.14 |
0.00 |
Warning: NLO event weights are not correct (negative gen-weights aren't subtracted), but the obs/predicted ratio is still useful
- Overall number of ttbar events are around ~1+-0.4, prediction to observed ratio: ~1.4+-0.3
- In all cases, the overall event number prediction stays very close to the observed number of events: ratio: 0.97 +-0.09, pulls are low too
5) Why TT+W/Z not similar to ttbar? Plot DeltaPhi shape for TTV
Plots attached. For some reason the Dphi distribution looks very similar regardless the Ntop/Dphi bin.
These are NLO samples, so I will need to correct for the negative weights.
6) When backgrounds are combined scaling might not work:
--> Try mixing together different ratios of bacgrounds to check how robust the method is
If I scale ttbar by 2 times the cross section, the pull gets larger, the ratio is sligthly lower, but still within statistical error.
- Should we apply a ~3% correction to account for this?
- If I blow up ttbar to x5 xsec, the ratio is still 0.85 --> Should we simply add a systematic error?
The method seems to be very robust.
7) Try to find a way to describe why the method works from first principles
Plot correlation of Razor variables for all regions of the ABCD methods in TTbar (and other) samples, eg:
a) DeltaPhi vs MR/MTR for Ntop==2 and Ntop<2
The MTR vs DPhi plots show no correlation, that's great. MR vs DPhi shows some correlation, but I have an idea:
MR for the top-pair is uncorrelated to DPhi, this is potentially useful. But I have to update my top-pair definition to the latest recipe and rerun the code.
I am planning to do a full AK4/AK8/TT - R comparison to settle this issue (I already did for Phys14, but I only checked signal efficiency, which was very similar).
Hopefully TT-R is uncorrelated to DPhi and then the explanation why the method works might be finally there.
b) MR/MTR vs Ntop for DeltaPhi <2.7 and DeltaPhi >2.7
I missed these plots, sorry. They are on my to-do list. |
|
|