1. Search for New Vector Boson from Minimal Higgless Model at CMS (based on FastSimulation)
Bian J. G. Chen G. M.
CMS group
Institute of High Energy Physics
Wang J.X.
Theory division
Qi Wei Zhang B. He H.J. Kuang Y.P.
Qinghua University
China, Jan 28

2. Introdution Signal Backgrounds Event selection Summary
outline
Introdution
Signal
Backgrounds
Event selection
Summary

3. Introduction If Higgs do not exist, the unitarity
violation will apear in the scattering
of massive gauge W±Z0→ W±Z0.
To postpone unitarity, Higgsless models
are proposed—new weakly coupled
particles appear at the TeV scale.
The typical ones are :
5d Higgsless models —tower of KK
gauge states

4. Introduction(con’t) Minimal Higgsless model Hep-ph/0708.2588 predicts
Just one pair of new W1 ,Z1 bosons as
light as 400 GeV, in additon to SM weak
boson W, Z0 and a vector- like heavy
fermion.
W1 and Z1 do not decay to lepton pairs
Widths are narrow for 0.4 and 0.5 GeV
mass

5. Introduction(con’t) Feynman Digram pp→W1qq’ →W±Z0qq’
Invariant mass distribution of W±Z0 for
MW1=500GeV

6. Signal sample The generator authors are ones of Hep-ph/0708.2588
The process is
fraction(sub 1)/fraction(sub 2) ≈2
The element matrix is calculated at tree
level based on Minimal Higgsless Model.

7. Signal sample(con’t) the generator is interfaced with PYTHIA
for the initial and final state radiation and
parton hadronization.
Then interfaced with CMSSW_1_6_9 for
FastSimulation. The default pileup is taken
into account.

8. Cross sections and Events for and Luminosity = 50/fb
Signal sample(con’t)
Cross sections and Events
for
and Luminosity = 50/fb CS
EVTS
Norm fact
Preselection
550
1.576
1000
0.079
3μ:|η|<2.5 ,
pt>5 GeV,
q, q’: |η|<7.0 ,
pt>5 GeV
for parton like events
600
1.211
0.061
650
0.921
0.046
700
0.707
0.035
750
0.554
0.028
Mass units: GeV, CS units: fb, Norm=CS*LU/EVTS

9. Cross sections and Events for and Luminosity = 50/fb
Signal sample(con’t)
Cross sections and Events
for
and Luminosity = 50/fb CS
EVTS
Norm fact
Preselection
550
0.918
1000
0.046
3μ:|η|<2.5 ,
pt>5 GeV,
q, q’: |η|<7.0 ,
pt>5 GeV
600
0.682
0.034
650
0.525
0.026
700
0.384
0.019
750
0.294
0.015
Mass units: GeV, CS units: fb, Norm=CS*LU/EVTS

10. background samples The generators are PYTHIA.
The detector simulation is CMSSW_1_6_9
FastSimulation.
pp→ WZ0 →3 μν
cross section is fb
pp→ WZ0qq’ →3 μνqq’
cross section is 6.21E-2 fb
pp→ WW →2μ2ν
cross section is 8.21E+2 fb

11. background samples(con’t)
pp→ WW qq’ → 2μ2ν qq’
cross section = 1.42E+3 fb
pp→ Z0 Z0 →4μ
cross section =17.57fb
pp→ Z0 Z0qq’ →4μqq’
cross section=5.48E-3fb
pp→ ttbar →W+W-qq’ →2μqq’
cross section =5.73E+03 fb
pp→ Zbb →2μbb
cross section =1.54E+05 fb

12. background samples(con’t)
Cross sections and Events
set luminosity = 50/fb
Process
CS(fb)
EVTS
Norm fact
Preselection
WZ0
97.33
29550
0.164
Default
Parameters
of Pythia
integrated with
CMSSW
WZ0qq’
6.21E-2
1200
0.003 WW
8.21E+2
164750
0.249
WWqq’
1.42E+3
283750
0.251
Z0Z0
17.57
83800
0.010
Z0Z0qq’
5.48E-3
13570
2.E-6
ttbar
5.73E+3
574400
0.499
Z0bb
1.54E+5
8.25E+6
0.932

13. Events selection Cut 1: Number of muons is required to be 3, including
Eachμis ParamGlobalMuons,
and satisfies
and within
∆R=sqrt(∆ η2+ ∆φ2) <0.3,
Super Cluster energy <5 GeV.

14. Events selection(con’t)
Cut 2: number of Jets≥1,Each Jet is iterativeCone5CaloJets, satisfies

15. Events selection(con’t)
Cut 2: number of isolated Jets≥1(con’t)

16. Events selection(con’t)
Cut 2: number of jets≥1(con’t)

17. Events selection(con’t)
Cut 3: Highest momentum of 3μ>150 GeV.

18. Events selection(con’t)
Cut 3: Highest p of 3μ>150 GeV(con’t)

19. Events selection(con’t)
Cut 3: Highest p of 3μ>150 GeV(con’t)

20. Events selection(con’t)
Cut 4:scalar sum of 3μPt

21. Events selection(con’t)
Cut 4:scalar sum of 3μPt (con’t)

22. Events selection(con’t)
Cut 4:scalar sum of 3μPt (con’t)

23. Events selection(con’t)
Cut 5: |mz |< 15 GeV,
maximal momentum of 2μ> 70 GeV

24. Events selection(con’t)
Cut 5: |mz |< 15 GeV,maximal
momentum of 2μ> 70 GeV (con’t)

25. Events selection(con’t)
Cut 5: |mz |< 15 GeV,maximal
momentum of 2μ> 70 GeV(con’t)

26. Events selection(con’t)
Cut 6: 0<MtW< 340 GeV

27. Events selection(con’t)
Cut 6: 0<MtW< 340 GeV(con’t)

28. Events selection(con’t)
Cut 6: 0<MtW< 340 GeV (con’t)

29. Events selection(con’t)
Cut 7: maximal p of jets>200 GeV

30. Events selection(con’t)
Cut 7: maximal p of jets>200 GeV (con’t)

31. Events selection(con’t)
Cut 7: maximal p of jets>200 GeV (con’t)

32. Cut 8: 540<Mhwz<1600 GeV Which is different from transverse mass
Events selection
Cut 8: 540<Mhwz<1600 GeV
Which is different from transverse mass

33. Events selection(con’t)
Cut 8: 540<Mhwz<1600 GeV (con’t)
Mhwz
Mtwz

34. Events selection(con’t)
Cut 8: 540<Mhwz<1600 GeV (con’t)

35. Events selection(con’t)
Cut 8: 540<Mhwz<1600 GeV(con’t)

36. Events selection(con’t)
Final Events and Significance
Significance =sqrt(2lnQ),Q=(1+Ns/Nb)Nbexp(-Nb),
Ns=19.4,Nb=8.3 for W1 mass=700 GeV
Significance: 5.3 for luminosity=50/fb,
i.e. Significance: 5. for luminosity=44.7/fb

37. Events selection(con’t)
Efficiency of cuts , here W1 mass = 700 GeV
PROCESS
CR*50/fb
Num of
μs= 3
Jets≥1
Maxi p of
3μ>150
W1+
35.4
21.9(61.90%)
21.4(60.60%)
21.3(60.40%)
W1-
19.2
11.9(61.70%)
11.5(59.70%)
11.3(58.80%) WZ
4858.5
1510(31.08%)
423(8.69%)
241.3(4.96%)
WZqq’
3.1
1.6(50.50%)
1.5(47.92%)
0.97(31.17%) ZZ
878.5
204(23.23%)
54.7(6.23%)
31.82(3.62%)
ZZqq’
0.27
0.09(32.07%)
0.08(29.73%)
0.06(20.13%) WW
41035
26.7(0.06%)
9.7(0.02%)
6.0(0.01%)
WWqq’
71200
125 (0.18%)
98.9(0.14%)
43.7(0.06%)
ttbar
286675
12140(4.24%)
9727(3.39%)
4312(1.50%)
Z0bb
50583(0.66%)
10401(0.14%)
3173(0.04%)
Sig
Background

38. Events selection(con’t)
Efficiency of cuts (con’t)
PROCESS
sum of
3μpt> 300
|mZ |
<15
Mtw<340
W1+
18.5(52.40%)
15.9(44.9%)
15.7(44.3%)
W1-
10.2(52.90%)
8.9(46.30%)
8.8(45.8%) WZ
29.4(0.61%)
23.9(0.49%)
23.7(0.49%)
WZqq’
0.22(7.08%)
0.20(6.50%) ZZ
3.4(0.39%)
2.6(0.29%)
2.5(0.29%)
ZZqq’
0.01(2.92%)
0.007(2.66%)
0.007(2.63%) WW
1.0(0.002%)
0(0.00%)
WWqq’
0.7(0.001%)
ttbar
192.7(0.07%)
31.9(0.010%)
31.4(0.01%)
Z0bb
1.76(0.23E-4%)
0.89(0.11E-4%)
Sig
Background

39. Events selection(con’t)
Efficiency of cuts (con’t)
PROCESS
Maxi p
of Jets > 200
540<mw1<1600
Final
Events
W1+
14.3(40.60%)
12.4(35.10%)
19.4
W1-
7.8(40.60%)
7.0(36.6%) WZ
13.5(0.28%)
5.9(0.12%)
8.3
WZqq’
0.19(6.08%)
0.05(1.75%) ZZ
1.3(0.15%)
0.4(0.046%)
ZZqq’
0.007(2.49%)
0.003(0.98%) WW
0(0.00%)
WWqq’
ttbar
21.5(0.007%)
2.0(0.0006%)
Z0bb
Sig
Background

40. Events selection M (GeV) Signal Bg Signif Luminosity for5σ(fb-1) 550
Events left and Significance as function of W1mass for luminosity of 50/fb
M (GeV)
Signal Bg
Signif
Luminosity for5σ(fb-1)
550
8.3
6.9
26.4
600
7.1
24.7
650
6.4
30.8
700
5.3
44.7
750
4.5
60.6

41. Summary We study discovery potential of new
charged boson W1 based on FastSimulation
If W1 mass is 600 GeV, We can find
5 sigma Signal with data of 24.7/fb .
If W1 mass is 750 GeV, We can find
5 sigma Signal with data of 60.6/fb