Angular analyses at CMS Alessio Boletti 1 on behalf of the CMS - - PowerPoint PPT Presentation

SLIDE 1

Angular analyses at CMS

Alessio Boletti1

• n behalf of the CMS collaboration

Rare B Decays workshop Apr 18th, 2016

1INFN & Universita‘ di Padova

• A. Boletti

Angular analyses at CMS Rare B Decays 2016 1 / 15

SLIDE 2

Introduction

Angular analyses at CMS

• A. Boletti

Angular analyses at CMS Rare B Decays 2016 2 / 15

SLIDE 3

Introduction

Angular analyses at CMS

B+ → K ∗+µµ analysis ongoing too few events to measure complete Pi set aiming at FL, AFB and dBR/dq2 B+ → K +µµ analysis ongoing scalar K meson: only AFB and dBR/dq2 measured Λb → Λµµ analysis started

• A. Boletti

Angular analyses at CMS Rare B Decays 2016 3 / 15

SLIDE 4

Introduction

Angular analyses at CMS

B0 → K ∗0µµ with reduced parametrization public paper [Phys. Lett. B 753 (2016) 424-448] FL, AFB and dBR/dq2 measured B0 → K ∗0µµ with complete parametrization analysis ongoing aiming the measurement of P′

5

no approved results

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Angular analyses at CMS Rare B Decays 2016 4 / 15

SLIDE 5

B0 → K∗µµ

B0 → K ∗(892)0µ+µ−

K+ π− θK PB0 K*0 rest frame μ− μ+ θl PB0 μμ rest frame μ− μ+ K+ π− ϕ

Four-particle final state topology three decay angles: θK, θl, φ the square of dimuon invariant mass: q2

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Angular analyses at CMS Rare B Decays 2016 5 / 15

SLIDE 6

B0 → K∗µµ

CP-averaged angular distribution

3D angular distribution with 8 free parameter challenging fit convergence problems with few events

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Angular analyses at CMS Rare B Decays 2016 6 / 15

SLIDE 7

B0 → K∗µµ

CP-averaged angular distribution

Integrating out the φ angle no problems with efficiency: quite flat in φ measurement of FL and AFB

• A. Boletti

Angular analyses at CMS Rare B Decays 2016 7 / 15

SLIDE 8

B0 → K∗µµ

S-wave component

1 Γ d3Γ d cos θKd cos θldq2 = 9 16 2 3FS + 4 3AS cos θK

• (1 − cos2 θl)

+ (1 − FS)

• 2FL cos2 θK(1 − cos2 θl)

+ 1 2(1 − FL)(1 − cos2 θK)(1 + cos2 θl) + 4 3AFB(1 − cos2 θK) cos θl

• Also Kπ couple produced in S-wave configuration

FS, fraction of S-wave Kπ AS, S-P waves interference term Small contribution, but need to be included in the PDF

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Angular analyses at CMS Rare B Decays 2016 8 / 15

SLIDE 9

B0 → K∗µµ

Data samples

Dataset 2012 data: 20.5 fb−1 at √s = 8 TeV Signal and control channels naturally defined in q2 bins 7 signal bins (1–19 GeV) B0 → K ∗J/ψ control channel ( |q − mJ/ψ| < 3σq ) B0 → K ∗ψ′ control channel ( |q − mψ′| < 3σq ) Flavour mistag No PID: no difference between pion and kaon B0 flavour determined with the Kπ invariant mass 12–14% of events mistagged their contribution considered in the PDF, with flipped angles

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Angular analyses at CMS Rare B Decays 2016 9 / 15

SLIDE 10

B0 → K∗µµ

Efficiency

2D efficiency function computed on MC simulation 3rd degree (cos θK) x 5th degree (cos θK) polynomial fitted to binned efficiency both for correctly and wrongly tagged events efficiency function multiplies the fit PDF

• A. Boletti

Angular analyses at CMS Rare B Decays 2016 10 / 15

SLIDE 11

B0 → K∗µµ

Signal yields

) (GeV)

−

µ

+

µ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 5 10 15 20 25 30 35

CMS

(8 TeV)

1 −

20.5 fb

2

2.00 GeV − : 1.00

2

q 11 ± Signal yield: 84 Data Total fit

• Corr. tag sig.

Mistag sig. Background ) (GeV)

−

µ

+

µ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 10 20 30 40 50 60

CMS

(8 TeV)

1 −

20.5 fb

2

4.30 GeV − : 2.00

2

q 16 ± Signal yield: 145 Data Total fit

• Corr. tag sig.

Mistag sig. Background ) (GeV)

−

µ

+

µ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 10 20 30 40 50

CMS

(8 TeV)

1 −

20.5 fb

2

6.00 GeV − : 4.30

2

q 15 ± Signal yield: 118 Data Total fit

• Corr. tag sig.

Mistag sig. Background ) (GeV)

−

µ

+

µ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 20 40 60 80 100

CMS

(8 TeV)

1 −

20.5 fb

2

8.68 GeV − : 6.00

2

q 21 ± Signal yield: 253 Data Total fit

• Corr. tag sig.

Mistag sig. Background ) (GeV)

−

µ

+

µ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 20 40 60 80 100 120 140

CMS

(8 TeV)

1 −

20.5 fb

2

12.86 GeV − : 10.09

2

q 25 ± Signal yield: 362 Data Total fit

• Corr. tag sig.

Mistag sig. Background

Signal Mistagged signal Background

) (GeV)

−

µ

+

µ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 10 20 30 40 50 60 70

CMS

(8 TeV)

1 −

20.5 fb

2

16.00 GeV − : 14.18

2

q 18 ± Signal yield: 227 Data Total fit

• Corr. tag sig.

Mistag sig. Background ) (GeV)

−

µ

+

µ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 10 20 30 40 50 60 70 80

CMS

(8 TeV)

1 −

20.5 fb

2

19.00 GeV − : 16.00

2

q 18 ± Signal yield: 239 Data Total fit

• Corr. tag sig.

Mistag sig. Background

A total of more than 1400 signal events Clear yields in all the q2 bins Same yields in the ongoing full angular analysis

• A. Boletti

Angular analyses at CMS Rare B Decays 2016 11 / 15

SLIDE 12

B0 → K∗µµ

Fit strategy

Unibinned likelihood fit performed in each q2 bin Fitted m(Kπµµ), cos θK, cos θl Background shapes from fit to m(B0) sidebands Signal m(B0) shapes and fraction of mistagged events from MC Example of fit in special bin 1 < q2 < 6 GeV2

) (GeV)

−

µ

+

µ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 20 40 60 80 100 120 140

CMS

(8 TeV)

1 −

20.5 fb

2

6.00 GeV − : 1.00

2

q 24 ± Signal yield: 346 Data Total fit

• Corr. tag sig.

Mistag sig. Background )

Κ

θ cos(

• 1
• 0.8
• 0.6
• 0.4
• 0.2

0.2 0.4 0.6 0.8 1 Events / ( 0.1 ) 20 40 60 80 100 120 140 CMS (8 TeV)

1 −

20.5 fb

2

6.00 GeV − : 1.00

2

q Data Total fit

• Corr. tag sig.

Mistag sig. Background )

l

θ cos(

• 1
• 0.8
• 0.6
• 0.4
• 0.2

0.2 0.4 0.6 0.8 1 Events / ( 0.1 ) 20 40 60 80 100 120 140 CMS (8 TeV)

1 −

20.5 fb

2

6.00 GeV − : 1.00

2

q Data Total fit

• Corr. tag sig.

Mistag sig. Background

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Angular analyses at CMS Rare B Decays 2016 12 / 15

SLIDE 13

B0 → K∗µµ

Systematic uncertainties

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Angular analyses at CMS Rare B Decays 2016 13 / 15

SLIDE 14

B0 → K∗µµ

Results

)

2

(GeV

2

q 2 4 6 8 10 12 14 16 18

L

F 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Data 〉 SM, LCSR 〈 〉 SM, Lattice 〈

CMS

(8 TeV)

1 −

20.5 fb )

2

(GeV

2

q 2 4 6 8 10 12 14 16 18

FB

A

• 1
• 0.8
• 0.6
• 0.4
• 0.2

0.2 0.4 0.6 0.8 1 Data 〉 SM, LCSR 〈 〉 SM, Lattice 〈

CMS

(8 TeV)

1 −

20.5 fb )

2

(GeV

2

q 2 4 6 8 10 12 14 16 18 )

2 −

GeV ×

8 −

(10

2

q / d Β d 2 4 6 8 10 12 Data 〉 SM, LCSR 〈 〉 SM, Lattice 〈

CMS

(8 TeV)

1 −

20.5 fb

Shorter error bars: statistical only Blue boxes: SM predictions, form-factors with light-cone sum rules at low q2 and extrapolated to high q2

[JHEP 09 (2010) 089, JHEP 02 (2013) 010]

Red boxes: SM predictions, form-factors by lattice calculations

[Phys. Rev. D 89 (2014) 094501]

• A. Boletti

Angular analyses at CMS Rare B Decays 2016 14 / 15

SLIDE 15

B0 → K∗µµ

Conclusions

No CMS Pi results public yet Complex analysis with 4D fit Many systematic uncertainties to be calculated But new results is arriving CMS P′

5 measurement

B+ angular analyses

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SLIDE 16

Backup

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SLIDE 17

Backup

Table of results

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SLIDE 18

Backup

7+8 TeV combination vs. other experiments

)

2

(GeV

2

q 2 4 6 8 10 12 14 16 18

L

F

• 0.8
• 0.6
• 0.4
• 0.2

0.2 0.4 0.6 0.8 1 CMS (7, 8 TeV) LHCb BaBar Belle CDF )

2

(GeV

2

q 2 4 6 8 10 12 14 16 18

FB

A

• 1
• 0.8
• 0.6
• 0.4
• 0.2

0.2 0.4 0.6 0.8 1 CMS (7, 8 TeV) LHCb BaBar Belle CDF )

2

(GeV

2

q 2 4 6 8 10 12 14 16 18 )

2 −

GeV ×

8 −

(10

2

q / d Β d 2 4 6 8 10 12 CMS (7, 8 TeV) LHCb BaBar Belle CDF

Not present the last LHCb result

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