1. Monte-Carlo event generation for CEPC
Xin Mo
Institute of High Energy Physics
Nov. 20, 2015
Monte-Carlo event generation for the CEPC

2. Monte-Carlo event generation for the CEPC
Outline
Introduction of CEPC generation work
250GeV
350GeV
NLO plans
Monte-Carlo event generation for the CEPC

3. Monte-Carlo event generation for the CEPC
Basic information
Sample information:
CM energy: 250GeV
Luminosity: 5000fb-1 Polarization: unpolarized
ISR: on Beamstrahlung: off
Generator
Matrix element: Whizard1.95
Shower & hadronization: Pythia6.4
Monte-Carlo event generation for the CEPC

4. Monte-Carlo event generation for the CEPC
Workflow
Monte-Carlo event generation for the CEPC

5. Monte-Carlo event generation for the CEPC
Stdhep
Root
Marlin
Whizard, Pythia
Geant4, Mokka
Stdhep
Monte-Carlo event generation for the CEPC

6. Monte-Carlo event generation for the CEPC
Physics
Signal part (Higgs)
SM Background
2 fermions
4 fermions
6 fermions(350GeV)
Monte-Carlo event generation for the CEPC

7. Monte-Carlo event generation for the CEPC
Higgs signal
Higgs-strahlung
Vector boson fusion
Monte-Carlo event generation for the CEPC

8. Classification of 4 fermions
WW type
Mixing type
ZZ type
Single W type
Single mixing type
Single Z type
Monte-Carlo event generation for the CEPC

9. Workshop on Monti-Carlo for CEPC CFHEP
Cuts
Default cuts
Applied on the invariant mass of colored or charged particle pairs, on the energy of emitted photons or gluons, and on the momentum transfer to exchanged photons or gluons.
M ≥10GeV
Workshop on Monti-Carlo for CEPC CFHEP

10. Monte-Carlo event generation for the CEPC
Summary table
Cross sections [fb]
240GeV
250GeV qq
54662
50216
μ+μ-
4685
4405
single Z
4538
4734
single W
5086
5144
W+W-
16004
15484 ZZ
1079
1033 ZH
203
212
W fusion
5.36
6.72
Z fusion
0.50
0.63
Monte-Carlo event generation for the CEPC

11. Monte-Carlo event generation for the CEPC
Number of events
Monte-Carlo event generation for the CEPC

12. Monte-Carlo event generation for the CEPC
350GeV sample
Sample information
e+e-  ZH; SM backgrounds; ttbar;
350GeV; 1000fb-1; ISR on;
format: stdhep
Topology
Monte-Carlo event generation for the CEPC

13. Monte-Carlo event generation for the CEPC
6fermions
ttbar
consisting of down type quarks and two virtual W bosons
tt_dtdtutdtutdt, tt_dtdtutdtlv, tt_dtdtlvlv
ZWW
consisting of one virtual Z(excluding down types) and two virtual W bosons
named with prefix zww, 9 sub-processes
ZZZ
consisting of three virtual Z bosons(excluding up-down pairs)
named with prefix zzz, 12 sub-processes
Monte-Carlo event generation for the CEPC

14. Cross sections(6fermions)
Process
σ(fb-1)
tt_dtdtlvlv
11.656
tt_dtdtutdtlv
45.566
tt_dtdtutdtutdt
43.106
zww
10-1~1
zzz
~10-2
Monte-Carlo event generation for the CEPC

15. Monte-Carlo event generation for the CEPC
NLO process
Leading order:
Omega
Next-to-Leading order:
Openloops
Radiation
Vertex correction
Loop correction
Monte-Carlo event generation for the CEPC

16. Monte-Carlo event generation for the CEPC
NLO event generation
Openloops
Matching
Whizard
Powheg
Loop calculation
HepMC
LHEF
Pythia8
Hadronize
Monte-Carlo event generation for the CEPC

17. Monte-Carlo event generation for the CEPC
Cross sections
250GeV
ISR & beamstrahlung
NLO LO uu
11121
10760 dd
10227
9829 cc
11068
10459 ss
10100
9902 bb
10237
9822
LO vs NLO
Monte-Carlo event generation for the CEPC

18. Monte-Carlo event generation for the CEPC
Validation
Monte-Carlo truth level
Fast simulation
Full simulation
Monte-Carlo event generation for the CEPC

19. Monte-Carlo event generation for the CEPC
Summary
Mass production
250GeV signal and SM backgrounds
350GeV 6fermions backgrounds
NLO
Beginning for NLO study
Validation and cross check
Monte-Carlo event generation for the CEPC

20. Monte-Carlo event generation for the CEPC
Thanks
Thanks for attention!
Monte-Carlo event generation for the CEPC

21. Monte-Carlo event generation for the CEPC
Backup
Backup
Monte-Carlo event generation for the CEPC

22. Monte-Carlo event generation for the CEPC
Interfaces
OpenLoops for one-loop calculation; QCD correction
Powheg for shower matching
stdhep, lcio, lhe outputs
Monte-Carlo event generation for the CEPC