1. Nikolay’s Analysis: mSUGRA
Study #1
Nikolay’s Analysis: mSUGRA
02/11/05
ISAJET 7.6X – all SUSY processes at 14 TeV
50,000 events
Geverator-level study
Event selection: 2 high t-jets plus soft t-jets to choose c20-c20 events
PT(1st t)vis > 40, PT(2nd t)vis > 40, PT(3rd t)vis > 20
PT(J1)+ETmiss > 400 GeV
|h| < 2.5 for tau’s
2018/11/28
TAMU/Regina LHC Monte Carlo Study

2. TAMU/Regina LHC Monte Carlo Study
02/11/05
N(generated) = 50,000 events
tau5
tau9
tau14
2018/11/28
TAMU/Regina LHC Monte Carlo Study

3. TAMU/Regina LHC Monte Carlo Study
03/29/05
Dm=10
First ATLFAST simulation
 L dt = 160 fb-1 LS OS
OS-LS
Dm=15
2018/11/28
TAMU/Regina LHC Monte Carlo Study

4. Nikolay’s Analysis: mSUGRA
Study #3a
Nikolay’s Analysis: mSUGRA
05/07/05
ISAJET 7.6X – all SUSY processes at 14 TeV
50,000 events????
ATLFAST simulation
Event selection: 2 high t-jets plus soft t-jets to choose c20-c20 events
PT(1st t)vis > 40, PT(2nd t)vis > 40, PT(3rd t)vis > 20
PT(J1)+ETmiss > 400 GeV
|h| < 2.5 for tau’s
2018/11/28
TAMU/Regina LHC Monte Carlo Study

5. TAMU/Regina LHC Monte Carlo Study
Study #3b
ATLFAST simulation
05/07/05
 L dt = 160 fb-1
 L dt = 200 fb-1 LS OS
OS-LS
 L dt = 160 fb-1
 L dt = 120 fb-1
2018/11/28
TAMU/Regina LHC Monte Carlo Study

6. TAMU/Regina LHC Monte Carlo Study
Study #3c
05/07/05
2018/11/28
TAMU/Regina LHC Monte Carlo Study

7. TAMU/Regina LHC Monte Carlo Study
Next Step (5/07/05)
1) Keep all histograms with the same luminosity. Can you generate events equivalent to 200 fb-1?
2) Fit the LS shape as a function of mass (Dm)
3) Fit the OS-LS shape as
OS-LS(Dm)=N1xG (Dm)+N2xLS(Dm)
where
N1=number of signal events
N2=number of BG events
4) We need Dm = 6.5 GeV
5) Re-plot N1 vs Dm
2018/11/28
TAMU/Regina LHC Monte Carlo Study

8. TAMU/Regina LHC Monte Carlo Study
5/08/05
Adam/Paul vs. Nikolay
30 fb-1
(LHC 1 Yr)
Nevent(3t+1j+Emiss) = (NcountOS+NcountLS)/ 2
NOS-NLS
Fig. 1a
Fig. 1b
Mean+3s
Plots from
12/22/04
DM=12.38 GeV
<M(tt)>
74 events/30 fb-1 for DM=12.38 GeV LS OS
OS-LS
No detector simulation
ATLFAST simulation
 L dt = 120 fb-1
Similar Shape!!!
2018/11/28
TAMU/Regina LHC Monte Carlo Study

9. TAMU/Regina LHC Monte Carlo Study
Update
OS-LS(Dm)=N1xG (Dm)+N2xLS(Dm)
05/07/05
05/13/05
Study #3c
Study #4
Systematic shift?
2018/11/28
TAMU/Regina LHC Monte Carlo Study

10. Preliminary Result (1 of 2)
06/03/05
Preliminary Result (1 of 2)
1) ATLFAST simulation returns tau-jet and generic-jet objects smeared by detector resolutions.
2) Use random number generators to simulate
50% efficiency for tau jets (et = 50%)
1% (or 3%) fake rate for generic jets
3) For each events
a) Tau jet identified as tau
b) Tau jet identified as jet
c) Generic jet identified as tau
d) Generic jet identified as jet
4) We select events if “tau’s” in a) and c) pass our kinematical cuts for taus (40, 40 and 20 GeV):
PT(1st t)vis > 40, PT(2nd t)vis > 40, PT(3rd t)vis > 20
PT(J1)+ETmiss > 400 GeV
|h| < 2.5 for tau’s
5) Plot OS, LS, OS-LS mass distributions
2018/11/28
TAMU/Regina LHC Monte Carlo Study

11. Preliminary Result (2 of 2)
06/03/05
Preliminary Result (2 of 2)
DM = 14.5 GeV LS OS
OS-LS
 L dt = 145 fb-1
et = 50%
et = 50%
1% fake rate
3% fake rate
~150
x3 increase in LS
because of 3% fake rate?
~50
But small change in height
and wider width in OS-LS
2018/11/28
TAMU/Regina LHC Monte Carlo Study

12. TAMU/Regina LHC Monte Carlo Study
06/17/05
et = 100% fake = 0%
45.6 0.5, s =13.4
50.30.4, s =15.0
49.10.5, s =13.4
2018/11/28
TAMU/Regina LHC Monte Carlo Study

13. TAMU/Regina LHC Monte Carlo Study
06/17/05
et = 50% fake = 0%-5% x
Fig.1a
Fig.1c 0% 3%
45.8 1.4, s =12.5
44.50.8, s =12.4
Fig.1b
Fig.1d 1% 5%
43.91.2, s =14.3
45.31.0, s =13.9
2018/11/28
TAMU/Regina LHC Monte Carlo Study

14. TAMU/Regina LHC Monte Carlo Study
06/17/05
et = 50% fake = 0%-5%
Fig.2a
Fig.2c 0% 3%
Why different?
46.71.5, s et = 50%
50.00.7, s =14.2
(50.30.4, s et = 100%) ?
Systematically increasing …
Fig.2b
Fig.2d 1% 5%
49.30.7, s =12.8
51.00.5, s =14.8
2018/11/28
TAMU/Regina LHC Monte Carlo Study

15. TAMU/Regina LHC Monte Carlo Study
06/21-22/05
“Peak” Investigation
Assume an event with X real taus (t1, t2, … tX), and Y jets (j1, … jY).
Throw random numbers to simulate et = 50% (or 100%) and fake = 1% (or 3%, 5%).
Re-label X+Y objects. For example, t1, t2, t3(j), … tX, and j1, … j6(t), ... jY, where
t3(j) means a jet object misidentified as tau with the third leading ET.
j6(t) means a tau object misidentified as jet with the 6th leading ET.
Apply our event selection cuts – 3 taus + 1 jet + MET
Calculate two di-tau masses (M13 and M23), and classify
Case a) Both taus are real
Case b) One real and one fake
Case c) Both taus are fakes
2018/11/28
TAMU/Regina LHC Monte Carlo Study

16. TAMU/Regina LHC Monte Carlo Study
06/21-22/05
et = 100% fake = 1%
DM = 15.4 GeV and 210 fb-1 a) c)
NICE cancellation!
in b) and c). b)
a) Both taus are real.
b) One real and one fake
c) Both taus are fakes
2018/11/28
TAMU/Regina LHC Monte Carlo Study

17. TAMU/Regina LHC Monte Carlo Study
06/21-22/05
et = 100% fake = 3%
DM = 15.4 GeV and 210 fb-1 a) c)
NICE cancellation!
in b) and c).
What caused this peak in LS?? b)
a) Both taus are real.
b) One real and one fake
c) Both taus are fakes
2018/11/28
TAMU/Regina LHC Monte Carlo Study

18. TAMU/Regina LHC Monte Carlo Study
06/21-22/05
et = 100% fake = 0-5%
DM = 15.4 GeV and 210 fb-1 a) a)
50.30.40, s =15.0
51.60.29, s =15.7
fake = 0%
fake = 3%
Peaks are systematically
shifting … a) a)
50.90.35, s =15.4
51.80.27, s =16.2
fake = 1%
fake = 5%
2018/11/28
TAMU/Regina LHC Monte Carlo Study

19. TAMU/Regina LHC Monte Carlo Study
06/21-22/05
et = %
fake = 0-5%
210 fb-1
Not good fitting
2018/11/28
TAMU/Regina LHC Monte Carlo Study

20. TAMU/Regina LHC Monte Carlo Study
Model for our study
Hand-picked lines
e=efficiency; f = fake rate
2018/11/28
TAMU/Regina LHC Monte Carlo Study

21. TAMU/Regina LHC Monte Carlo Study
DM = 5.7 GeV and 210 fb-1
et = 100% fake = 0%
DM = 15.4 GeV and 210 fb-1
06/22/05
et = 50% fake = 0, 1, 3, 5%
2018/11/28
TAMU/Regina LHC Monte Carlo Study

22. TAMU/Regina LHC Monte Carlo Study
Ztt
ISAJET
(06/23/05)
ISAJET+ATLFAST
(06/19/05)
Mean=57.1
RMS=17.4 (31%)
Mean=68.3
RMS=28.2 (41%)
2018/11/28
TAMU/Regina LHC Monte Carlo Study

23. TAMU/Regina LHC Monte Carlo Study
06/28/05
Ztt
Mean=57.2
RMS=17.4 (31%)
Mean=63.3
RMS=16.0 (?%)
NAtlfast/NIsajet=83%
NAtlfast/NIsajet=57%
Why there is no low-mass tail on ATLFAST?
2018/11/28
TAMU/Regina LHC Monte Carlo Study

24. TAMU/Regina LHC Monte Carlo Study
07/14/05
fake = 0.5%
2018/11/28
TAMU/Regina LHC Monte Carlo Study

25. TAMU/Regina LHC Monte Carlo Study
07/14/05
Based on ISAJET (no detector simulation)
Three “true” taus are selected like in the analysis
Di-tau mass distribution in OS, LS, and OS-LS. a)
(a)
What is meant by
“Only PURE”
What is meant by
“only ONE PURE”?
2018/11/28
TAMU/Regina LHC Monte Carlo Study