1. CMS Physics Analysis in China
Guoming CHEN
IHEP, CAS
4/10/2019
Sino-French LHC workshop Guoming CHEN

2. Sino-French LHC workshop Guoming CHEN
Outline
Bc (IHEP)
J/ψ (PKU)
HVV (IHEP)
Dimuon trigger at low luminosity
(IHEP, PKU)
D0 (IHEP)
Plan
4/10/2019
Sino-French LHC workshop Guoming CHEN

3. Sino-French LHC workshop Guoming CHEN
Bc introduction
( c) ,Unique character: doubly heavy flavored.
Suggested by Prof. C.H. Chang (ITP)
The experimental study of Bc will help:
1) To study the heavy quark dynamics;
2) To test the spin symmetry derived in NRQCD
and HQET;
3) To tag Bs in mixing
4/10/2019
Sino-French LHC workshop Guoming CHEN

4. Sino-French LHC workshop Guoming CHEN
TEVATRON: CDF
20 J/ψ lυ events, mass : 6.40±0.13 GeV
life time : ps
4/10/2019
Sino-French LHC workshop Guoming CHEN

5. Sino-French LHC workshop Guoming CHEN
M(Bc):
6402.0±22.0 MeV
Input:6400MeV
cτ(Bc):
148.8±13.1 μm
Input 150 μm
4/10/2019
Sino-French LHC workshop Guoming CHEN

6. Sino-French LHC workshop Guoming CHEN
Systematic Summary
Bc mass (MeV)
Bc cτ (μm)
P scale 11
0.2
P smear 10
0.8
Vertex smear /
2.4
Cuts
0.1
Efficiency
Theoretical
1.5
Total
14.9
3.0
CMS 1/fb:
Mass: 22.0(fit) ±14.9(syst) MeV
lifetime: 0.044(fit) ±0.010(syst) ps
4/10/2019
Sino-French LHC workshop Guoming CHEN

7. This analysis is finished
2 notes：
Analysis-Note 2006/079
CMS-Note 2006/118
Approved by the CMS physics meeting
Included into the Physics TDR

8. Sino-French LHC workshop Guoming CHEN
Prompt J/ψ (PKU)
1-2 order of magnitude discrepancy between CSM prediction and CDF Result
Prompt charmonium production
black dot: CDF experiment
dashed line: color-singlet
solid line : NRQCD fit
4/10/2019
Sino-French LHC workshop Guoming CHEN

9. Sino-French LHC workshop Guoming CHEN
Problem: Polarization of Heavy Quarkonia
CDF RUN 1 results
PRL, 85 (2000) 2886
a=+1: transversely polarized
a=-1: longitudinally polarized
CDF RUN 2 results
4/10/2019
Sino-French LHC workshop Guoming CHEN

10. Sino-French LHC workshop Guoming CHEN
Quarkonia CMS
Higher luminosity:
 better statistics in general
 especially important for  which is
expected to be described better by NRQCD
Higher Collision Energy:
 larger cross-section
 higher PT region reached
Better Muon Measurement
 preferable for J/Y  m+m-,   m+m-
CMS will measure the cross section and polarization
More precisely
4/10/2019
Sino-French LHC workshop Guoming CHEN

11. Sino-French LHC workshop Guoming CHEN
Polarization extraction: The Loop Fitting
Normalize to the MC templates
Weighted efficiency
Signal Pt distribution
a=0 efficiency
Weighted efficiency ……
Solid Line is alpha input
Data point is alpha fit value
4/10/2019
Sino-French LHC workshop Guoming CHEN

12. Sino-French LHC workshop Guoming CHEN
Polarization extraction: Neural Network Fit
4/10/2019
Sino-French LHC workshop Guoming CHEN

13. HVV coupling measurement
To check:
whether there exists a sub-TeV Higgs Boson.
2. to discriminate new physics model from that of the SM.
4/10/2019
Sino-French LHC workshop Guoming CHEN

14. Sino-French LHC workshop Guoming CHEN
Prof. Y.P. Kuang
proposed a sensitive way to measure the HVVC via
like-sign leptons final states
It is d u v p + W + l + W H + v W + + p u W l d
4/10/2019
Sino-French LHC workshop Guoming CHEN

15. Sino-French LHC workshop Guoming CHEN
Extraction of coupling constant fw
through cross section
Normalized to 300 fb-1
4/10/2019
Sino-French LHC workshop Guoming CHEN

16. Through two leptons’ invariant mass
Normalized to 300 fb-1
4/10/2019
Sino-French LHC workshop Guoming CHEN

17. Sino-French LHC workshop Guoming CHEN
Backgrounds
channels
Sigma
Events/300 (fb )
Obtained via Grid job or reconstructed by myself
WZ l
4.4E-10 (mb)
32000
40000
ZZ l
1.6E-11 (mb)
4800
Z0 t t l + X
(fb)
510
1000
W+ t t l + X
(fb)
900
t t l + X
1.25E-9 (mb)
375000
121000
Zbb_4l+(njets)
2E (mb)
6000
129000
Zbb_cc_4l+(njets)
8E (mb)
2400
3000
ZWjets_leptonic
2.6E-9 (mb)
780000
50000
ZZjets_leptonic
1.5E-10 (mb)
45000
100000 -1 _ _ _
4/10/2019
Sino-French LHC workshop Guoming CHEN

18. Sino-French LHC workshop Guoming CHEN
Dimuon trigger study
With the first 1/fb data, it is intended to collect a large amount of:
1) prompt J/ψ to calibrate the detector and to study the polarization;
2) B hadrons contain J/ψ decay to check the performance of the detector; Bs→ J/ψ φ to study CP violation;
And to collect enough Bc to measure it’s mass and life time
They are all low pT stuff, low pT dimuon trigger is needed, but the HLT rates must be within the bandwidth allowed.
4/10/2019
Sino-French LHC workshop Guoming CHEN

19. Sino-French LHC workshop Guoming CHEN
Dimuon trigger study
QCD
μPt >3GeV
μPt >4GeV
μPt >5GeV
μPt >6GeV
μPt >7GeV
0_15
( 21.511.0)
(11.6 7.2)
( 2.42.1)
(0.9 1.0)
(0.3 0.5)
15_20
( 18.03.0)
( 12.62.3)
(5.4 1.2)
(2.30.6)
(1.0 0.3)
20_30
( 25.71.9)
(18.6 1.9)
( 11.61.3)
( 6.40.6)
(3.1 0.4)
30_50
( 23.41.6)
(18.7 1.6)
(12.3 0.9)
( 7.30.6)
(4.5 0.5)
50_80
( 13.90.4)
(11.3 0.4)
( 8.60.2)
(6.1 0.2)
( 4.00.2)
80_120
( 5.60.3)
(4.7 0.3)
( 3.80.3)
(2.8 0.1)
(2.1 0.1)
120_170
(1.9 0.0)
(1.6 0.5)
( 1.30.0)
(1.0 0.0)
(0.8 0.0)
170_230
(0.7 0.0)
(0.6 0.0)
(0.4 0.0)
(0.3 0.0)
230_300
( 0.20.0)
(0.2 0.0)
(0.1 0.0)
300_380
380_470
(0.0 0.0)
( 0.00.0)
Total
(111 11.7)
( 80.18.0)
(46.3 2.9)
( 27.51.5)
( 16.30.9)
QCD rate at 1033
4/10/2019
Sino-French LHC workshop Guoming CHEN

20. Sino-French LHC workshop Guoming CHEN
D0 reconstruction
To monitor the calibration and alignment status through:
momentum scale, resolution
vertex resolution
To calibrate the mu/h and e/h separation
To calibrate the PDL resolution for Bc life time measurement
4/10/2019
Sino-French LHC workshop Guoming CHEN

21. Sino-French LHC workshop Guoming CHEN
1,100,000 events
pb-1 QCD D0
QCD
4/10/2019
Sino-French LHC workshop Guoming CHEN

22. Sino-French LHC workshop Guoming CHEN
Our study show that:
The number of D0’s collected one day at 5x1029
(900GeV collision) is about
Enough to check the momentum scale and resolution
4/10/2019
Sino-French LHC workshop Guoming CHEN

23. Sino-French LHC workshop Guoming CHEN
Plan
Blind search through (IHEP)
dimuon final states
WZ final states (Z→μμ)
Higgs search through H→ZZ, Z→μμ, Z→υυ (IHEP)
Heavy Majorana neutrino search (IHEP)
Higgs→DM (PKU)
Top polarization &CP violation study (PKU)
4/10/2019
Sino-French LHC workshop Guoming CHEN