0 ˇ ˇ )K0 Time Dependent CP sensitivity S study for...

B0 → η′(→ ηπ+π−)K0S Time Dependent ��CP sensitivity

study for BelleIISlides shown at B2TIP on 24 May 2016

Stefano [email protected]

INFN Padova

Belle II Italia,Padova, 30 May 2016

S.Lacaprara (INFN Padova) B0 → η

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mailto:[email protected]

Introduction and motivations

A sensitivity study for Time-Dependent CP violation analysis in theB0 → η′K0channel, a charmless b → sqq decay

CP asymmetry from time-dependentdecay rate into CP eigenstates;

B0 → η′K0is a penguin dominated mode

Precision not competitive with that from golden channel B0 → J/ψφ

Sη′K

0 = sin 2φeff1 tightly related to sin 2φ1 measured in b → css decay

identical if only penguin diagram were present: not so;I QCD factorization: ∆Sη′K 0 ∈ [−0.03, 0.03][Williamson and Zupan(2006)]

I SU(3)F approach: ∆Sη′K 0 ∈ [−0.05, 0.09][Gronau et al.(2006)]

I new physics can enter in the loop,shifting ∆Sη′K 0 more than SM expectation

B0

η′

K0

b

d

s

s

s

g

W

u, c, t


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Current results

Channel have been analyzed in B-factory[BABAR(2009), Belle(2007), Belle(2014)];

analysis based on quasi-two body approach;

sin 2φeff1 = +0.68± 0.07± 0.03 [Belle(2014)] = +0.57± 0.08± 0.02 [BABAR(2009)]

uncertainties are mostly statistical (∼ 3500 events for all final states);I syst: ±0.025 from ∆t resolution, ±0.014 from vertexing, ±0.013 from η′K0

S

fraction;

η′ K0 S

CP

HF

AG

Moriond 2

014

0.5 0.6 0.7 0.8

BaBar

PRD 79 (2009) 052003

0.57 ± 0.08 ± 0.02

Belle

JHEP 1410 (2014) 165

0.68 ± 0.07 ± 0.03

Average

HFAG correlated average

0.63 ± 0.06

H F A GH F A GMoriond 2014

PRELIMINARY

projected for 50 ab−1 σstat = 0.008, σsyst = 0.008[Urquijo(2015)]

no competition from LHCb


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Decay channels

many decay channels available B0 → η′K0

decay channel

η′ → ρ0(→ π+π−)γ BR=29% not yet

η′ → ηπ+π− 43% today

↘ η → γγ 40% ηγγ↘ η → π+π−π0 23% η3π

K 0S → π+π− 69% today

K 0S → π0π0 31% just started

K0L not yet

B0 → η′(→ηγγ /η3ππ+π−

)K0S(→π+

π−

) BR=19%

Complex final state, neutrals, large combinatorics;

final states considered so far in red

more to be studied (ρ0,K 0S → π0π0,K0

L)


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Selection

candidate selection: main cuts

Reconstruct decay chain with mass constrains for π0, η, η′, K0S,

I vertex only (w/o mass) for B0 (more later)

� π0, ηγγ :

I 0.06 < Eγ < 6 GeV, E9/E25 > 0.75

I M(π0) ∈ [100, 150] MeV

I M(ηγγ) ∈ [0.52, 0.57] GeV;

� η′ → ηγγπ+π−:

I d0(π±) < 0.08mm;z0(π±) < 0.1mm;

I N hitsPXD (π±) > 1, PID

I M(η′) ∈ [0.93, 0.98] GeV;

� η′ → η3ππ+π−:

I M(η′) ∈ [0.93, 0.98] GeV;

� K0 → π+π−:

I M(K0S → π+π−) ∈ [0.48, 0.52] GeV;

� B0 → η′(→ ηγγπ+ π−)K0

S+−

I Mbc > 5.25 GeV;

I |∆E | < 0.1 GeV;

� B0 → η′(→ η3ππ+π−)K0

S+−

I |∆E | < 0.15 GeV;

if Ncands > 1, select that with best reduced χ2 for η, η′,K0S inv. masses


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Signal distribution B0 → η′(→ ηγγπ+ π−)K0

S

+−

Best candidates, after selections

bcM5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.290

5000

10000

15000

20000

25000

30000

35000

Mbc

Best cands

" MC match

" SXF

Mbc

E∆0.2− 0.15− 0.1− 0.05− 0 0.05 0.1 0.15 0.20

5000

10000

15000

20000

25000

30000

35000

40000

ηM0.4 0.45 0.5 0.55 0.6 0.65 0.70

10000

20000

30000

40000

50000

'ηM0.85 0.9 0.95 1 1.05 1.1 1.150

20

40

60

80

100

120

140

160

180

200

310×

S0KM

0.45 0.46 0.47 0.48 0.49 0.5 0.51 0.52 0.53 0.54 0.551

10

210

310

410

510

/KπLL∆20− 10− 0 10 20 30 40 501

10

210

310

410

)-π+π(S

0) K-π+π γγη'( η→0B


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Signal distribution B0 → η′(→ η3ππ+π−)K0

S

+−

Best candidates, after selections

bcM5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.291

10

210

310

410

Mbc

Best cands

" MC match

" SXF

Mbc

E∆0.2− 0.15− 0.1− 0.05− 0 0.05 0.1 0.15 0.21

10

210

310

410

ηM0.4 0.45 0.5 0.55 0.6 0.65 0.71

10

210

310

410

510

'ηM0.85 0.9 0.95 1 1.05 1.1 1.151

10

210

310

410

510

0πM0.08 0.1 0.12 0.14 0.16 0.18 0.21

10

210

310

410

/KπLL∆20− 10− 0 10 20 30 40 501

10

210

310

)-π+π(S

0) K-π+π π3

η'( η→0B


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Efficiency and combinatorics

channel ε % SxF % cands/ev

B0 → η′(→ ηγγπ+ π−)K0

S (→ π+π−) 29.4 1.1 1.06

B0 → η′(→ η3ππ+π−)K0

S(→ π+π−) 12.1 3.1 1.45

B0 → η′(→ ηγγπ+ π−)K0

S (→ π0π0) 13.5 2.2 ∼ 5

B0 → η′(→ η3ππ+π−)K0

S(→ π0π0) 6.0 3.8 ∼ 30

Efficiency drop due to π0 reco, likely to improve;

presence of π0 increase also combinatorics and signal cross feed

SxF : signal event but with wrong particle association;

B0 → η′(→ η3ππ+π−)K0

S(→ π0π0) not used in Belle and BaBaranalysis.


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Vtx reco and ∆t resolution: ηγγchannel

1 Fit the B0 vertex from charged tracks; (π± from η′ → ηπ±)2 add also constraint from reconstructed K 0

S direction; (K0S → π+π−)

3 add also constraint from B0 boost direction, transverse plane only.

(ps)truet∆t-∆10− 8− 6− 4− 2− 0 2 4 6 8 10

0

5000

10000

15000

20000

25000

/ ndf 2χ 867 / 191

Prob 0

norm 8.0e+01± 6.3e+04

CBias 0.0025±0.0307 −

Cσ 0.005± 0.629

T

Bias 0.00485±0.00735 − Tσ 0.01± 1.63

OBias 0.015± 0.132

Oσ 0.03± 4.46

Cf 0.005± 0.344

Tf 0.003± 0.443

Fit

Core

Tail

Outlier

t: 1.89 ps∆Bias: 0.01 ps

)-π+π(S

0) K-π+π γγ

η'( η→0B

Standard

(ps)truet∆t-∆10− 8− 6− 4− 2− 0 2 4 6 8 10

0

100

200

300

400

500

600

700

/ ndf 2χ 253 / 191

Prob 0.00177

norm 1.24e+01± 1.54e+03

CBias 0.013±0.047 −

Cσ 0.033± 0.587

T

Bias 0.0313±0.0524 −

T

σ 0.12± 1.47

OBias 0.080± 0.107

Oσ 0.15± 3.81

Cf 0.041± 0.393

Tf 0.028± 0.393

Fit

Core

Tail

Outlier

t: 1.62 ps∆Bias: -0.02 ps

)-π+π(S

0) K-π+π γγ

η'( η→0B

WithK0S

(ps)truet∆t-∆10− 8− 6− 4− 2− 0 2 4 6 8 10

0

5000

10000

15000

20000

25000

30000

35000

40000

/ ndf 2χ 1.02e+03 / 191

Prob 0

norm 7.8e+01± 6.1e+04

CBias 0.0013±0.0399 −

Cσ 0.002± 0.488

T

Bias 0.0036±0.0704 − Tσ 0.01± 1.14

OBias 0.018± 0.429

Oσ 0.02± 2.97

Cf 0.005± 0.565

Tf 0.004± 0.362

Fit

Core

Tail

Outlier

t: 0.91 ps∆Bias: -0.02 ps

)-π+π(S

0) K-π+π γγ

η'( η→0B

WithB0 dir.

&K0S

With beamspot (x , y) & K0S:

No efficiency lossimportant improvement in ∆tresolution1.89→ 1.62→ 0.91 ps


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Vtx reconstruction for B0 → η′(→ η3ππ+π−)K0

S+−

Standard reconstruction uses four charged tracks:π± from η′ → ηπ± and η → π±π0

(ps)truet∆t-∆10− 8− 6− 4− 2− 0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

/ ndf 2χ 499 / 191

Prob 29− 2.06e

norm 5.65e+01± 3.19e+04

CBias 0.0027±0.0223 −

Cσ 0.005± 0.535

T

Bias 0.0052±0.0277 −

T

σ 0.01± 1.29

OBias 0.019± 0.266

Oσ 0.03± 3.15

Cf 0.007± 0.401

Tf 0.01± 0.46

Fit

Core

Tail

Outlier

t: 1.25 ps∆Bias: 0.02 ps

)-π+π(S

0) K-π+π π3

η'( η→0B

Standard

(ps)truet∆t-∆10− 8− 6− 4− 2− 0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

/ ndf 2χ 629 / 191

Prob 0

norm 5.49e+01± 3.02e+04

CBias 0.002±0.036 −

Cσ 0.003± 0.445

T

Bias 0.0050±0.0562 −

T

σ 0.01± 1.07

OBias 0.021± 0.317

Oσ 0.02± 2.88

Cf 0.007± 0.565

Tf 0.006± 0.342

Fit

Core

Tail

Outlier

t: 0.88 ps∆Bias: -0.01 ps

)-π+π(S

0) K-π+π π3

η'( η→0B

WithB0 dir.

&K0S

With B0 dir. & K0S:

No efficiency loss1.25→ 0.88 psIn both cases, ∆t resolution better than in Belle, in spite of lower boost


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Backgrounds

Combinatorial: from continuum background e+e− → uu, dd , ss, ccI evaluated from Mbc side bands on real dataI now from MC production: NB: still w/o machine background!I use Continuum Suppression variable

F multivariate variables sensitive to event topologyF central (signal) vs jet-like (continuum)

Peaking: any other B decays possibly with real η′ and/or K0S

I evaluated from MC of generic B0B0, B+B−

F actual B0 → η′K0 removed.

Current results based on BGx0 production, namely w/o machinebackgroundI impact of machine background under study

Next table numbers before Continuum Suppression cut


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Background reduction (before CS cut)

Sample uu dd ss cc contiuum B0B0 B+B−

Input ev (M) 1284 321 306 1063 2974 429 420

B0 → η′(→ ηγγπ+ π−)K0

S

+−

εsel (·10−6) 2.69 3.06 2.40 3.62 3.0 0.11 0.038

ev for 300 fb−1 1247 369 275 1445 3335 18 6

B0 → η′(→ η3ππ+π−)K0

S

+−

εsel (·10−6) 0.34 0.54 0.17 1.50 0.76 0.14 0.02

ev for 300 fb−1 166 65 20 597 847 24 3

Background reduction better for η3π than for ηγγηγγ mostly uu and ccη3π mostly cc

peaking background is small

preliminary study on w/ machine background shows similar rates


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Background distributionsBest candidates, after selections

5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.29

20

40

60

80

100

120

bcM

mixedcharged

uuddss

cc

0.2− 0.15− 0.1− 0.05− 0 0.05 0.1 0.15 0.2

20

40

60

80

100

120

140

160

180

200

E∆0.4 0.45 0.5 0.55 0.6 0.65 0.7

50

100

150

200

250

300

350

400

ηM

0.85 0.9 0.95 1 1.05 1.1 1.15

200

400

600

800

1000

1200

1400

1600

'ηM0.45 0.46 0.47 0.48 0.49 0.5 0.51 0.52 0.53 0.54 0.55

100

200

300

400

500

600

S0KM

20− 10− 0 10 20 30 40 50

1

10

210

/KπLL∆

)-π+π(S

0) K-π+π) γγ(η'( η→0B


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Background distributionsBest candidates, after selections

5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.29

5

10

15

20

25

30

35

40

bcM

mixedcharged

uuddsscc

0.2− 0.15− 0.1− 0.05− 0 0.05 0.1 0.15 0.2

5

10

15

20

25

30

35

40

45

E∆0.4 0.45 0.5 0.55 0.6 0.65 0.7

100

200

300

400

500

ηM

0.85 0.9 0.95 1 1.05 1.1 1.15

100

200

300

400

500

600

700

'ηM0.08 0.1 0.12 0.14 0.16 0.18 0.2

20

40

60

80

100

120

140

160

0πM0.45 0.46 0.47 0.48 0.49 0.5 0.51 0.52 0.53 0.54 0.55

20

40

60

80

100

120

140

160

180

S0K

M

)-π+π(S

0) K-π+π) 0π-π+π(η'( η→0B


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Continuum suppression

0.5− 0.4− 0.3− 0.2− 0.1− 0 0.1 0.2 0.3 0.4 0.5

50

100

150

200

250

300

350

BDTBDT

mixedchargeduuddsscc

Signal

)-π+π(S

0) K-π+π) γγ(η'( η→0B

Signal efficiency

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Ba

ck

gro

un

d r

eje

cti

on

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

MVA Method:

BDT

Background rejection versus Signal efficiency

Working point

Tight: BDT > 0.124, εsignal = 50%, (1− εbackground ) = 97.5%,

Loose: BDT > −0.055, εsignal = 95%, (1− εbackground ) = 58%,

no cut: include the BDT in the likelihood new


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Likelihood fit

Multi dim. extended maximum likelihood fit to extract S and C.

Pdf is of the form:P i

j = Tj

(∆t i , σi

∆t , ηiCP

)︸︷︷︸

time-dep part

∏k Qk,j (x

ik )︸︷︷︸

time integrated

time-dependent part, taking into account mistag rate (ηf = ±1 is CP state):

f (∆t) =e−|∆t|/τ

4τ

{1∓∆w ± (1− 2w)

×[− ηf Sf sin(∆m∆t)− Cf cos(∆m∆t)

]}

variables (xk ) used, in addition to ∆t

Mbc

∆E

Cont. Suppr. new

Parameters:

effective tagging efficiency:Q = ε(1− 2w)2 = 0.33I w = 0.21, ∆w = 0.02

∆t resolution as shown previously(convoluted)

τ , ∆m from PDGS.Lacaprara (INFN Padova) B

0 → η′K

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PDF fit results examples

t (ps)∆25− 20− 15− 10− 5− 0 5 10 15 20 25

Eve

nts

/ ( 1

ps

)

0

20

40

60

80

100

120

310×t"∆A RooPlot of "

/ ndf = 448.9472χ 0.00096± = -2.598130 CPC

0.0025± = -0.05562 CPS

t"∆A RooPlot of "

(GeV)bcM5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.29

Eve

nts

/ ( 0

.001

GeV

)

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

"bcA RooPlot of "M / ndf = 17.4532χ

0.016± = 0.800 Cf 0.000026 GeV± = 5.279880

Cµ

0.000088 GeV± = 5.277700 T

µ 0.000010 GeV± = 0.002437 Cσ 0.000022 GeV± = 0.002899 Tσ

"bcA RooPlot of "M

E (GeV)∆0.1− 0.08− 0.06− 0.04− 0.02− 0 0.02 0.04 0.06 0.08 0.1

Eve

nts

/ ( 0

.005

GeV

)

0

10000

20000

30000

40000

50000

E"∆A RooPlot of " / ndf = 9.0902χ

0.0046± = 0.7305 Cf 0.000042 GeV± = -0.0044460

Cµ

0.00016 GeV± = -0.009065 T

µ 0.000066 GeV± = 0.019073 Cσ

0.00029 GeV± = 0.04174 Tσ

E"∆A RooPlot of "

bdt0.5− 0.4− 0.3− 0.2− 0.1− 0 0.1 0.2 0.3 0.4 0.5

Eve

nts

/ ( 0

.025

)

0

10000

20000

30000

40000

50000

60000

A RooPlot of "bdt" / ndf = 1148.3152χ

0.00040± = 0.16288 µ 0.00026± = 0.12623 Lσ 0.00024± = 0.06823 Rσ

A RooPlot of "bdt"

Signal

t (ps)∆25− 20− 15− 10− 5− 0 5 10 15 20 25

Eve

nts

/ ( 1

ps

)

0

20

40

60

80

100

120

310×t"∆A RooPlot of "

/ ndf = 448.9472χ 0.00096± = -2.598130 CPC

0.0025± = -0.05562 CPS

t"∆A RooPlot of "

(GeV)bcM5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.29

Eve

nts

/ ( 0

.001

GeV

)

0

200

400

600

800

1000

1200

1400

1600

1800

2000


0.019± = 0.625 Cf 0.000083 GeV± = 5.280310

Cµ

0.00025 GeV± = 5.27408 T

µ 0.000051 GeV± = 0.003010 Cσ

0.00011 GeV± = 0.00495 Tσ

2.1± = -90.00 ξ 0.099±n = 1.036

0.0058± = 0.9238 Pf

"bcA RooPlot of "M

E (GeV)∆0.1− 0.08− 0.06− 0.04− 0.02− 0 0.02 0.04 0.06 0.08 0.1

Eve

nts

/ ( 0

.005

GeV

)

0

100

200

300

400

500

600

700


0.0020 GeV± = -0.03822 de

µ

0.0024 GeV± = 0.1000 deσ

E"∆A RooPlot of "

bdt0.5− 0.4− 0.3− 0.2− 0.1− 0 0.1 0.2 0.3 0.4 0.5

Eve

nts

/ ( 0

.025

)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200


0.0021± = 0.1373 µ 0.0013± = 0.1188 Lσ 0.0013± = 0.0768 Rσ

A RooPlot of "bdt"

SxF

t (ps)∆25− 20− 15− 10− 5− 0 5 10 15 20 25

Eve

nts

/ ( 1

ps

)

0

2

4

6

8

10

12

14

16

t"∆A RooPlot of " / ndf = 0.6702χ

0.31± = 0.34 CPC

0.53± = -0.626 CPS

t"∆A RooPlot of "

(GeV)bcM5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.29

Eve

nts

/ ( 0

.001

GeV

)

0

1

2

3

4

5

6

7


0.00081 GeV± = 5.27752 µ 0.00065 GeV± = 0.00305 σ

76± = -89.9 ξ 0.79±n = 1.69 0.12± = 0.58 Pf

"bcA RooPlot of "M

E (GeV)∆0.1− 0.08− 0.06− 0.04− 0.02− 0 0.02 0.04 0.06 0.08 0.1

Eve

nts

/ ( 0

.005

GeV

)

0

1

2

3

4

5

6


0.070± = 0.500 Cf 0.010 GeV± = 0.033

Cµ

0.17 GeV± = -0.100 T

µ 0.0015 GeV± = 0.0300 Cσ

0.020 GeV± = 0.069 Tσ

E"∆A RooPlot of "

bdt0.5− 0.4− 0.3− 0.2− 0.1− 0 0.1 0.2 0.3 0.4 0.5

Eve

nts

/ ( 0

.025

)

0

2

4

6

8

10


0.053± = -0.0330 µ 0.031± = 0.044 Lσ 0.038± = 0.169 Rσ

A RooPlot of "bdt"

Peaki

ngbkg

nd

t (ps)∆25− 20− 15− 10− 5− 0 5 10 15 20 25

Eve

nts

/ ( 1

ps

)

0

1000

2000

3000

4000

5000

6000

t"∆A RooPlot of " / ndf = 1.2942χ

0.0068 ps± = 0.0183 CBias

0.21 ps± = -0.237 TBias

0.0060± = 0.9640 Cf

0.00074± = 0.00103 Of

0.016 ps± = 0.119 CScale

0.22 ps± = 2.40 TScale

t"∆A RooPlot of "

(GeV)bcM5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.29

Eve

nts

/ ( 0

.001

GeV

)

0

50

100

150

200

250

300


3.1± = -29.69 ξ 0.000049 GeV± = 5.286950 endE

"bcA RooPlot of "M

E (GeV)∆0.1− 0.08− 0.06− 0.04− 0.02− 0 0.02 0.04 0.06 0.08 0.1

Eve

nts

/ ( 0

.005

GeV

)

0

50

100

150

200

250


0.20± = -1.256 1

p

3.8± = 0.5 2

p

E"∆A RooPlot of "

bdt0.5− 0.4− 0.3− 0.2− 0.1− 0 0.1 0.2 0.3 0.4 0.5

Eve

nts

/ ( 0

.025

)0

50

100

150

200

250

300

350

400

450


0.0033± = -0.10286 µ 0.0020± = 0.0493 Lσ 0.0023± = 0.1110 Rσ

A RooPlot of "bdt"

Contin

uum

∆T Mbc ∆E CS variable


′K

0S B2Italia 30/05/2016 17 / 21

Toy MC

Testing fit machinery with Toy MC;

Yield estimated for L = 300 fb−1

N(BB) ∼ 330 · 106

width of distribution related to the expected statistical uncertainty;

check also for bias;

input CP asymmetry parameter: S=0.7 C=0.0

testing two different CS scenarios:I TightI LooseI No cut

Partially embedded toysI Signal and SXF from MC;I Continuum and Peaking background from pdf;


′K

0S B2Italia 30/05/2016 18 / 21

Toy results B0 → η′(→ ηγγπ+ π−)K0

S+−

L = 300 fb−1, N(BB) ∼ 330 · 106:Nsig = 390, Nsxf = 15, Ncont = 3300, Npeak = 30

0.2− 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.60

10

20

30

40

50

60

70

Toy results - dtSig_S Entries 1000

Mean 0.0079± 0.703

Std Dev 0.00559± 0.25

Toy results - dtSig_S

0.2− 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.60

10

20

30

40

50

60

70

80


Mean 0.00572± 0.703

Std Dev 0.00405± 0.181


0.2− 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.60

10

20

30

40

50

60

70

80


Mean 0.00563± 0.696

Std Dev 0.00398± 0.178


TightLoose

No Cut

σS = 0.26 0.181 0.178

Par Bias RMS

S (0.7) 0.696± 0.005 0.178C (0.0) 0.005± 0.004 0.13nSig 390.7± 0.8 24.7Prelim

inaryresults

Belle (772 · 106 BB): Nsig = 648, σS = 0.15, σC = 0.10

BaBar (467 · 106 BB): Nsig = 472, σS = 0.17, σC = 0.11S.Lacaprara (INFN Padova) B

0 → η′K

0S B2Italia 30/05/2016 19 / 21

Toy results B0 → η′(→ η3ππ+π−)K0

S+−

Loose

L = 300 fb−1, N(BB) ∼ 330 · 106:Nsig = 106, Nsxf = 25, Ncont = 360, Npeak = 27

0.2− 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.60

10

20

30

40

50


Mean 0.0105± 0.708

Std Dev 0.00742± 0.33


0.6− 0.4− 0.2− 0 0.2 0.4 0.60

10

20

30

40

50

Toy results - dtSig_C Entries 995

Mean 0.00785± 0.00127

Std Dev 0.00555± 0.246

Toy results - dtSig_C

0 20 40 60 80 100 120 140 160 180 2000

5

10

15

20

25

30

35

40

45

Toy results - nSig Entries 995

Mean 0.587± 110

Std Dev 0.415± 18.5

Toy results - nSig

Par Bias RMS

S (0.7) 0.708± 0.010 0.330C (0.0) −0.013± 0.008 0.246nSig 110.2± 0.6 18.5Prelim

inaryresults

Belle1 (772 · 106 BB): Nsig = 104, σS = 0.21, σC = 0.18

BaBar (467 · 106 BB): Nsig = 105, σS = 0.26, σC = 0.201including also η′ → ρ0γ


′K

0S B2Italia 30/05/2016 20 / 21

Summary

First presentation on sensitivity study for ��CP in B0 → η ′K0S channel;

not complete, yet, but preliminary results are encouraging;I comparison with Belle and BaBar results looks fine;

many thing to do:I include machine backgroundI complete K0

S → π+π− channels;I study K0

S → π0π0 final states;

I add η′ → ρ0γK0S

+−/K0

S

00channel;

I systematics uncertainties evaluation;I documentationI . . .

More results (and work) for next B2TIP workshop.


′K

0S B2Italia 30/05/2016 21 / 21

Additional stuff

Additional or backup slides


′K

0S B2Italia 30/05/2016 1 / 16

Selection

good candidate selection B0 → η′(→ ηγγπ+ π−)K0

S+−

:

Reconstruct decay chain with mass constrains for η, η′, K0S,

I vertex only (w/o mass) for B0

� η → γγ :

I gamma:all: 0.06 < Eγ < 6 GeV,−150 < clustime < 0, E9/E25 > 0.75

I M(ηγγ) ∈ [0.52, 0.57] GeV;

� η′ → ηγγπ+π−:

I pi:all

I ∆logL(π,K) > −10; new

I d0(π±) < 0.08mm;

I z0(π±) < 0.1mm;

I N hitsPXD (π±) > 1

I M(η′) ∈ [0.93, 0.98] GeV;

� K0 → π+π−:

I K S0:mdst

I M(K0S → π+π−) ∈ [0.48, 0.52] GeV;

� B0 → η′(→ ηγγπ+ π−)K0

S+−

I Mbc > 5.25 GeV;

I |∆E | < 0.1 GeV;

I P-valuevtx (B0, η′,K 0

S ) > 1 · 10−5

if Ncands > 1, select candidate with highest P-valuevtx (B0, η′, η,K 0

S )


′K

0S B2Italia 30/05/2016 2 / 16

Selection breakdonw

1.000

0.570

0.463 0.458

0.4140.392 0.378 0.378 0.376 0.370 0.361

0.3360.305 0.294

0.011

InputSkim Reco bc

M E∆ ηM

'ηM

K_SM

/K)πLogL(

∆0

d0

z N Hits vtxP TRUE

SXF0

0.2

0.4

0.6

0.8

1

Events statistics

Selections MC true /SXF

)-π+π(S

0) K-π+π γγ

η'( η→0BEvents statistics

Combinatorics

Cands mult.: 1.88Good cands mult.: 1.06

Efficiency %skim 57.0preselection 46.1good cands 30.5MC true 29.4SXF 1.1


′K

0S B2Italia 30/05/2016 3 / 16

Signal distribution B0 → η′(→ ηγγπ+ π−)K0

S+−

bcM5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.290

10000

20000

30000

40000

50000

60000

70000

Mbc

All cands

MC match

Good cands

" MC match

Mbc

E∆0.2− 0.15− 0.1− 0.05− 0 0.05 0.1 0.15 0.20

10000

20000

30000

40000

50000

60000

ηM0.4 0.45 0.5 0.55 0.6 0.65 0.70

10000

20000

30000

40000

50000

60000

70000

80000

90000

'ηM0.85 0.9 0.95 1 1.05 1.1 1.150

50

100

150

200

250

310×

S0

KM

0.45 0.46 0.47 0.48 0.49 0.5 0.51 0.52 0.53 0.54 0.551

10

210

310

410

510

/KπLL∆20− 10− 0 10 20 30 40 501

10

210

310

410

)-π+π(S

0) K-π+π γγη'( η→0B


′K

0S B2Italia 30/05/2016 4 / 16

Selection

good candidate selection B0 → η′(→ η3ππ+π−)K0

S+−

:

Reconstruct decay chain with mass constrains for η, η′, K0S,

I vertex only (w/o mass) for B0

� π0:

I gamma:all: 0.06 < Eγ < 6 GeV,−150 < clustime < 0, E9/E25 > 0.75

I M(π0) ∈ [100, 150] MeV

� η → π+π−π0:

I pi:all

I ∆logL(π,K) > −10; new

I M(η3π) ∈ [0.52, 0.57] GeV;

I d0(π±) < 0.08mm;

I z0(π±) < 0.1mm;

I N hitsPXD (π±) > 1

� η′ → η3ππ+π−:

I M(η′) ∈ [0.93, 0.98] GeV;

� K0 → π+π−:

I K S0:mdst

I M(K0S → π+π−) ∈ [0.48, 0.52] GeV;

� B0 → η′(→ η3ππ+π−)K0

S+−

I Mbc > 5.25 GeV;

I |∆E | < 0.15 GeV;

I P-valuevtx (B0, η′,K 0

S ) > 1 · 10−5

if Ncands > 1, select candidate with highest P-valuevtx (B0, η′, η,K 0

S )


′K

0S B2Italia 30/05/2016 5 / 16

Selection breakdonw

1.000

0.572

0.464

0.398

0.265

0.1870.170 0.164 0.164 0.163 0.162 0.161 0.158 0.151

0.121

0.030

InputSkim Reco bc

M E∆ ηM

'ηM

0πM

K_SM

/K)πLogL(

∆0

d0

z N Hits vtxP TRUE

SXF0

0.2

0.4

0.6

0.8

1

Events statistics

Selections MC true /SXF

)-π+π(S

0) K-π+π π3

η'( η→0BEvents statistics

Combinatorics

Cands mult.: 21.5Good cands mult.: 1.45

Efficiency %skim 57.2preselection 46.2good cands 15.1MC true 12.1SXF 3.0

Reco eff is as good as ηγγ channel.

50% eff drop due to poor resolution on Mbc , ∆E , Mη all coming from π0 reconstruction

in η → π+π−π0 decay


′K

0S B2Italia 30/05/2016 6 / 16

Signal distribution B0 → η′(→ η3ππ+π−)K0

S+−

bcM5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.291

10

210

310

410

510

Mbc

All cands

MC match

Good cands

" MC match

Mbc

E∆0.2− 0.15− 0.1− 0.05− 0 0.05 0.1 0.15 0.21

10

210

310

410

510

ηM0.4 0.45 0.5 0.55 0.6 0.65 0.71

10

210

310

410

510

610

'ηM0.85 0.9 0.95 1 1.05 1.1 1.151

10

210

310

410

510

610

0πM0.08 0.1 0.12 0.14 0.16 0.18 0.21

10

210

310

410

510

610

/KπLL∆20− 10− 0 10 20 30 40 501

10

210

310

410

510

)-π+π(S

0) K-π+π π3

η'( η→0B


′K

0S B2Italia 30/05/2016 7 / 16

Vtx reco: signal and tag sideB0 → η′(→ ηγγπ

+ π−)K0S

+−

z (signal) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

100

200

300

400

500

600

700

800

900

/ ndf 2χ 93.4 / 91

Prob 0.41

norm 0.1± 15.6

C

Bias 0.000097± 0.000393

C

σ 0.00015± 0.00371

T

Bias 0.000216± 0.000459

T

σ 0.00054± 0.00924

O

Bias 0.00056± 0.00166

O

σ 0.0013± 0.0269

Cf 0.03± 0.33

Tf 0.022± 0.368

Fit

Core

Tail

Outlier

mµz: 127.55 ∆mµ: 8.00 zBias

z (tag) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

200

400

600

800

1000

1200

1400

1600

1800

2000

/ ndf 2χ 121 / 91

Prob 0.0208

norm 0.1± 16.1

C

Bias 0.000043± 0.000524

C

σ 0.00007± 0.00235

T

Bias 0.00011± 0.00104

T

σ 0.00026± 0.00605

O

Bias 0.00052±0.00199 −

O

σ 0.0006± 0.0185

Cf 0.025± 0.497

Tf 0.021± 0.383

Fit

Core

Tail

Outlier

mµz: 56.96 ∆mµ: 4.23 zBias

)-π+π(S

0) K-π+π γγ

η'( η→0B

Standard

z (signal) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

200

400

600

800

1000

1200

/ ndf 2χ 110 / 91

Prob 0.0839

norm 0.1± 15.2

C

Bias 0.000111± 0.000355

C

σ 0.000± 0.006

T

Bias 0.0001± 0.0002

T

σ 0.00011± 0.00228

O

Bias 0.00035± 0.00101

O

σ 0.0004± 0.0212

Cf 0.017± 0.472

Tf 0.013± 0.207

Fit

Core

Tail

Outlier

mµz: 101.07 ∆mµ: 5.35 zBias

z (tag) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

200

400

600

800

1000

1200

1400

1600

1800

/ ndf 2χ 117 / 91

Prob 0.0348

norm 0.1± 15.5

CBias 0.00004± 0.00052

C

σ 0.00007± 0.00233

T

Bias 0.00011± 0.00104

Tσ 0.00025± 0.00604

OBias 0.00054±0.00211 −

O

σ 0.0006± 0.0186

Cf 0.02± 0.49

Tf 0.02± 0.39

Fit

Core

Tail

Outlier

mµz: 57.22 ∆mµ: 4.09 zBias

)-π+π(S

0) K-π+π γγ

η'( η→0B

WithK0S

z (signal) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

10000

20000

30000

40000

50000

60000

70000

80000

/ ndf 2χ 940 / 91

Prob 0

norm 0.8± 609

C

Bias 0.000017± 0.000435

C

σ 0.00004± 0.00534

T

Bias 0.000006± 0.000233

T

σ 0.0000± 0.0024

O

Bias 0.000± 0.005

O

σ 0.0001± 0.0156

Cf 0.005± 0.357

Tf 0.005± 0.583

Fit

Core

Tail

Outlier

mµz: 42.44 ∆mµ: 5.93 zBias

z (tag) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

10000

20000

30000

40000

50000

60000

70000

/ ndf 2χ 1.02e+03 / 91

Prob 0

norm 0.8± 608

C

Bias 0.000007± 0.000498

C

σ 0.00001± 0.00245

T

Bias 0.00002± 0.00103

T

σ 0.00005± 0.00625

O

Bias 0.00008±0.00122 −

O

σ 0.0001± 0.0179

Cf 0.004± 0.527

Tf 0.003± 0.356

Fit

Core

Tail

Outlier

mµz: 56.17 ∆mµ: 4.88 zBias

)-π+π(S

0) K-π+π γγ

η'( η→0B

WithBS &

K0S


′K

0S B2Italia 30/05/2016 8 / 16

Vtx reco: signal and tag sideB0 → η′(→ η3ππ

+π−)K0S

+−

z (signal) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

5000

10000

15000

20000

25000

/ ndf 2χ 774 / 91

Prob 0

norm 0.6± 318

C

Bias 0.000025± 0.000762

C

σ 0.000± 0.006

T

Bias 0.000016± 0.000333

T

σ 0.00002± 0.00242

O

Bias 0.00008± 0.00432

O

σ 0.0001± 0.0174

Cf 0.004± 0.465

Tf 0.003± 0.296

Fit

Core

Tail

Outlier

mµz: 76.55 ∆mµ: 14.81 zBias

z (tag) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

5000

10000

15000

20000

25000

30000

35000

/ ndf 2χ 674 / 91

Prob 0

norm 0.6± 319

C

Bias 0.000010± 0.000499

C

σ 0.00002± 0.00245

T

Bias 0.000027± 0.000983

T

σ 0.00007± 0.00616

O

Bias 0.00011±0.00148 −

O

σ 0.0001± 0.0179

Cf 0.006± 0.511

Tf 0.005± 0.369

Fit

Core

Tail

Outlier

mµz: 56.71 ∆mµ: 4.41 zBias

)-π+π(S

0) K-π+π π3

η'( η→0B

Stan

dard

z (signal) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

5000

10000

15000

20000

25000

30000

35000

40000

45000

/ ndf 2χ 1.34e+04 / 91

Prob 0

norm 0.5± 301

C

Bias 0.00004± 0.00112

C

σ 0.00006± 0.00435

T

Bias 0.000007± 0.000199

T

σ 0.00001± 0.00205

O

Bias 0.000± 0.005

O

σ 0.0001± 0.0142

Cf 0.008± 0.285

Tf 0.009± 0.624

Fit

Core

Tail

Outlier

mµz: 38.10 ∆mµ: 8.98 zBias

z (tag) (cm)∆0.05− 0.04− 0.03− 0.02− 0.01− 0 0.01 0.02 0.03 0.04 0.050

5000

10000

15000

20000

25000

30000

35000

/ ndf 2χ 634 / 91

Prob 0

norm 0.5± 301

C

Bias 0.000028± 0.000995

C

σ 0.00007± 0.00619

T

Bias 0.000010± 0.000496

T

σ 0.00002± 0.00246

O

Bias 0.00012±0.00148 −

O

σ 0.0002± 0.0179

Cf 0.005± 0.366

Tf 0.006± 0.515

Fit

Core

Tail

Outlier

mµz: 56.70 ∆mµ: 4.43 zBias

)-π+π(S

0) K-π+π π3

η'( η→0B

With

BS

&K

0S


′K

0S B2Italia 30/05/2016 9 / 16

Background distributionAll candidates

5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.29

1000

2000

3000

4000

5000

6000

bcM

mixedcharged

uuddss

cc

0.2− 0.15− 0.1− 0.05− 0 0.05 0.1 0.15 0.2

2000

4000

6000

8000

10000

12000

14000

E∆0.4 0.45 0.5 0.55 0.6 0.65 0.7

2000

4000

6000

8000

10000

12000

14000

16000

18000

ηM

0.85 0.9 0.95 1 1.05 1.1 1.15

5000

10000

15000

20000

25000

30000

'ηM0.45 0.46 0.47 0.48 0.49 0.5 0.51 0.52 0.53 0.54 0.55

10000

20000

30000

40000

50000

60000

70000

80000

90000

S0KM

20− 10− 0 10 20 30 40 50

1

10

210

310

410

/KπLL∆

)-π+π(S

0) K-π+π) γγ(η'( η→0B


′K

0S B2Italia 30/05/2016 10 / 16

Background distributionAll candidates

5.25 5.255 5.26 5.265 5.27 5.275 5.28 5.285 5.29

10000

20000

30000

40000

50000

bcM

mixedcharged

uuddsscc

0.2− 0.15− 0.1− 0.05− 0 0.05 0.1 0.15 0.2

20

40

60

80

100

120

140

310×

E∆0.4 0.45 0.5 0.55 0.6 0.65 0.7

50

100

150

200

250

300

350

400

450

310×

ηM

0.85 0.9 0.95 1 1.05 1.1 1.15

100

200

300

400

500

600

310×

'ηM0.08 0.1 0.12 0.14 0.16 0.18 0.2

100

200

300

400

500

310×

0πM0.45 0.46 0.47 0.48 0.49 0.5 0.51 0.52 0.53 0.54 0.55

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

310×

S0K

M

)-π+π(S

0) K-π+π) 0π-π+π(η'( η→0B


′K

0S B2Italia 30/05/2016 11 / 16

Continuum Suppression correlation matrix

100−

80−

60−

40−

20−

0

20

40

60

80

100

B0_ThrustB

B0_ThrustO

B0_CosTBTO

B0_CosTBz

B0_R2B0_cc1

B0_cc2B0_cc3

B0_cc4B0_cc5

B0_cc6B0_cc7

B0_cc8B0_cc9

B0_mm2B0_et

B0_hso00

B0_hso02

B0_hso04

B0_hso10

B0_hso12

B0_hso14

B0_hso20

B0_hso22

B0_hso24

B0_hoo0B0_hoo1

B0_hoo2B0_hoo3

B0_hoo4

B0_ThrustBB0_ThrustO

B0_CosTBTOB0_CosTBz

B0_R2B0_cc1B0_cc2B0_cc3B0_cc4B0_cc5B0_cc6B0_cc7B0_cc8B0_cc9

B0_mm2B0_et

B0_hso00B0_hso02B0_hso04B0_hso10B0_hso12B0_hso14B0_hso20B0_hso22B0_hso24B0_hoo0B0_hoo1B0_hoo2B0_hoo3B0_hoo4

Correlation Matrix (signal)

100 2 2 1 3 3119 7 2 2 1 2 1 1 2 1 2 1 2100 17 3 65 12 16 14 9 1102025 5 8 3 32 4 5 27 5 12 9 4 4 1 54 2 20 2 17100 8 61 8 24 30 25 15 183746 8 14 7 52 6 16 63 17 12 29 12 11 1 15 2 4 1 3 8100 4 2 1 9 910 8 3 5 8 742 1 3 71213 6 9 311 5 1 3 65 61 4100 9 20 24 16 216344854 101422 61 13 52 20 1 26 1417 33 1 16 31 8 2 910059 9 3 5 2 6 7 6 11 18 1 5 3 6 1 4 219 12 24 1 2059100 7 1 1 2 4 5 414 18 2 14 11 21 36 37 16 18 11 20 1 18 8 7 16 30 9 24 9 7100 3 3 5 7 822 31 4 22 6 31 44 15 24 20 6 30 25 9 2 14 25 9 16 1 3100 1 1 4101118 34 8 22 7 31 3219 18 6 2 30 1 21 2 1 2 9 1510 2 1 1100 2101219 32 13 1625 28 1730 16 3 30 2 17 2 1 1 816 2 3 1 100 4 5 617 26 16 127 22 24 12 5 5 25 7 2 2

1018 334 4 5 4 2 4100 14 22 142011 211311 11 9 6 23 1 3 22037 548 5 71010 5 100 712 16 1636 12 1724 8 911 6 20 1 42546 854 4 81112 6 710014 15 1643 29 1627 19 1010 5 21 6 1 1 5 8 7 10 314221819171412141005524 55321388411379 164 235

2 8 144214 5 18 31 34 32 26 22 16 1555100 31 4 1 83 47 9 51 11 1 86 1 41 1 8 1 3 7 122 2 2 4 8 13 16 14 16 1624 31100 5 5 6 2 2 2 2 1 29 5 7 5 1 32 52 3 61 6 14 22 22 16 1203643 4 5100 7 2 16 2 2 5 3 2 20 3 2 4 6 7 7 11 6 7252711 12 29 1 5 7100 1 2 3 1 1 1 1 5 1 5 161213 6 21 31 31 28 22 21 17 1655 83 6 2 1100 52 17 58 15 1 87 1 42 11 2 27 6313 52 11 36 44 32 17 13242732 47 2 16 2 52100 42 36 43 19 46 42 1 15

5 17 6 20 18 37 1519302411 8 1913 9 2 2 3 17 42100 16 29 20 15 15 1 13 12 12 9 1 1 16 24 18 16 12 11 9 1088 51 2 2 1 58 36 16100 41 11 75 61 34 9 29 26 5 18 20 6 5 9111041 11 2 5 15 43 29 41100 44 23 45 33 4 12 3 14 3 11 6 2 3 5 6 6 513 1 1 3 1 19 20 11 44100 3 16 22 4 111117 6 20 30 30 30 25 23 20 2179 86 29 87 46 15 75 23 3100 53 2 18 1 1 1 1 1 2 1 1 1 5 2 1 1 100 28 2

1 54 15 5 33 4 18 25 21 17 7 1 4 664 41 7 20 1 42 42 15 61 45 16 53 100 1 54 2 2 1 2 2 2 3 1 2 1 5 1 1 1 2 28 1100 1 20 4 1 16 2 8 9 1 2 2 135 8 3 5 11 15 13 34 33 22 18 2 54 1100

Linear correlation coefficients in %

100−

80−

60−

40−

20−

0

20

40

60

80

100

B0_ThrustB

B0_ThrustO

B0_CosTBTO

B0_CosTBz

B0_R2B0_cc1

B0_cc2B0_cc3

B0_cc4B0_cc5

B0_cc6B0_cc7

B0_cc8B0_cc9

B0_mm2B0_et

B0_hso00

B0_hso02

B0_hso04

B0_hso10

B0_hso12

B0_hso14

B0_hso20

B0_hso22

B0_hso24

B0_hoo0B0_hoo1

B0_hoo2B0_hoo3

B0_hoo4

B0_ThrustBB0_ThrustO

B0_CosTBTOB0_CosTBz

B0_R2B0_cc1B0_cc2B0_cc3B0_cc4B0_cc5B0_cc6B0_cc7B0_cc8B0_cc9

B0_mm2B0_et

B0_hso00B0_hso02B0_hso04B0_hso10B0_hso12B0_hso14B0_hso20B0_hso22B0_hso24B0_hoo0B0_hoo1B0_hoo2B0_hoo3B0_hoo4

Correlation Matrix (background)

100 2 3 8 10 381816 5 5 2 4 8 2 3 1 5 4 2 4 2 4 4 2 4 3 2 2100 41 88 9 26 22 13 325344649 4 5 8 45 25 10 53 30 8 21 14 5 51 3 32 3 41100 6 49 6 18 20 8 115263443 1 3 1 33 20 4 41 18 19 9 1 5 19 5 12 8 6100 9 10 4171713 5 8 863 2 1 42919 612 4 523 3 7 6 3 10 88 49 9100 19 21 13 32139454951 112121 41 3414 44 39 9 21 1720 2 36 2 33 38 9 6 10 19100571313 3 5 3 1 6 6 14 19 3 6 21 2 3 2 1 5 6 4 918 26 18 4 2157100 6 1 2 3 6 6 619 22 6 22 22 25 36 33 18 20 18 25 1 33 2 2516 22 2017 1313 6100 8 4 3 4 9 422 37 7 12 5 36 46 17 23 11 5 34 1 31 2 9 5 13 817 313 1 8100 511 1 2 515 36 8 1113 34 2221 18 3 6 31 21 2

3 11321 2 4 5100 1 1 1 20 30 13 419 30 726 18 3 5 32 2 10 5 52515 539 3 3 311 1100 2 11 418 17 19 713 151220 15 6 8 23 3 5 13

3426 845 5 6 4 1 1 2100 5 714 19 121917 161412 13 7 3 20 9 5 8 24634 49 6 9 2 1 11 5100 8 6 13 1423 8 1318 613 9 16 116 211

4943 51 3 6 4 5 4 7 810011 13 1718 1 927 3 8 8 6 16 515 1 8 4 4 1 8 11 1192215201814 611100473419 548341587583479 572 546 8 5 36321 6 22 37 36 30 17 19 13 1347100 29 17 1 80 53 10 48 7 81 44 4 9 2 8 1 221 6 6 7 8 13 19 12 14 1734 29100 55 23 812 5 13 2 3510 14 8 2 3 45 33 1 41 14 22 12 11 4 719231819 17 55100 64 4 4 8 8 7 2013 35 7 20 1 25 20 4 34 19 22 513191317 8 1 5 1 23 64100 7 2 3 3 310 18 4 21 5 10 42914 3 25 36 34 30 15 16 13 948 80 8 4 7100 69 21 55 14 5 83 3 50 1 15 4 53 4119 44 6 36 46 22 71214182734 5312 4 2 69100 57 38 33 21 55 4 63 2 34 2 30 18 6 39 21 33 1721262012 315 10 5 21 57100 13 30 28 17 37 2 36 4 8 12 9 2 18 23 18 18 15 13 6 887 48 13 8 55 38 13100 60 33 77 70 45 2 21 19 4 21 3 20 11 3 3 6 713 858 7 2 8 3 14 33 30 60100 62 31 2 69 3 58 4 14 9 5 17 2 18 5 6 5 8 3 9 634 7 3 5 21 28 33 62100 15 4 42 49 4 5 12320 1 25 34 31 32 23 20 16 1679 81 35 20 3 83 55 17 77 31 15100 2 65 3 27 2 5 3 2 5 1 1 2 3 1 5 5 101310 3 4 2 4 2100 38 3 4 51 19 7 36 6 33 31 21 10 5 9161572 44 14 35 18 50 63 37 70 69 42 65 100 5 69 3 3 5 6 2 4 2 2 2 5 2 1 5 4 8 7 4 1 2 2 3 3 38 5100 1 2 32 12 3 33 9 25 9 513 811 846 9 2 20 21 15 34 36 45 58 49 27 3 69 1100

Linear correlation coefficients in %


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S+−

Tight CS

Tight: εsig ,sxf ,peaking = 50%, εcontinuum = 2.5%

Nsig = 195, Nsxf = 8, Ncont = 83, Npeak = 15

0.2− 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.60

10

20

30

40

50

60

70


Mean 0.0079± 0.703

Std Dev 0.00559± 0.25


0.6− 0.4− 0.2− 0 0.2 0.4 0.60

10

20

30

40

50

60

70

80


Mean 0.00539± 0.0103

Std Dev 0.00381± 0.17


0 50 100 150 200 250 300 350 4000

20

40

60

80

100

120

140


Mean 0.403± 195

Std Dev 0.285± 12.7

Toy results - nSig

Par Bias RMS

S (0.7) 0.703± 0.008 0.25C (0.0) 0.010± 0.005 0.17nSig 195.4± 0.4 12.7


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S+−

Loose CS

Loose: εsig ,sxf ,peaking = 95%, εcontinuum = 42%

Nsig = 390, Nsxf = 14, Ncont = 1400, Npeak = 28

0.2− 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.60

10

20

30

40

50

60

70

80


Mean 0.00572± 0.703

Std Dev 0.00405± 0.181


0.6− 0.4− 0.2− 0 0.2 0.4 0.60

10

20

30

40

50

60

70

80

90


Mean 0.00441± 0.00198

Std Dev 0.00312± 0.139


0 100 200 300 400 500 600 700 8000

20

40

60

80

100

120


Mean 0.804± 390

Std Dev 0.568± 25.4

Toy results - nSig

Par Bias RMS

S (0.7) 0.703± 0.005 0.18C (0.0) 0.002± 0.004 0.14nSig 389.8± 0.8 25.4


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Comparison with Belle/BaBar

This analysis? Belle[Belle(2014)] BaBar[BABAR(2009)]

mode (340 M B B) (772 M B B) (467 M B B)

η′ → π±η Nsig σS σC Nsig σS σC Nsig σC σS

ηγγK0S

+−390 0.19 0.11 648 0.15 0.098 472 0.17 0.11

ηγγK0S

00Just started 104 0.21† 0.18† 105 0.34 0.30

η3πK0S

+−106 0.33 0.25 174 0.26 0.18 171 0.26 0.20

η3πK0S

00Will try Not used

η′ → ρ0γK0S

+−Not yet 1411 0.098 0.069 1005 0.12 0.09

η′ → ρ0γK0S

00Not yet 162 0.21† 0.18† 206 0.33 0.26

?Very preliminary estimate based on toy MC, L = 300 fb−1

Warning: no machine background yet†Results combining η′ → π±ηγγ and η′ → ρ0γ


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Bibliography I

[Williamson and Zupan(2006)] Alexander R. Williamson and Jure Zupan. Two body b decays with isosinglet final states in softcollinear effective theory. Phys. Rev. D, 74:014003, Jul 2006. doi: 10.1103/PhysRevD.74.014003. URLhttp://link.aps.org/doi/10.1103/PhysRevD.74.014003.

[Gronau et al.(2006)] Michael Gronau et al. Updated bounds on cp asymmetries in B0 → η

′KS and B

0 → π0

KS . Phys.Rev. D, 74:093003, Nov 2006. doi: 10.1103/PhysRevD.74.093003. URLhttp://link.aps.org/doi/10.1103/PhysRevD.74.093003.

[Belle(2014)] Belle. Measurement of time-dependent cp violation in b0 → η′k0 decays. Journal of High Energy Physics, 2014

(10):165, 2014. doi: 10.1007/JHEP10(2014)165. URL http://dx.doi.org/10.1007/JHEP10%282014%29165.

[Urquijo(2015)] Phillip Urquijo. Comparison between belle ii and lhcb physics projections. Technical ReportBELLE2-NOTE-PH-2015-004, Apr 2015.

[CLEO(1998)] CLEO. Observation of high momentum η′

production in B decays. PRL, 81:1786, 1998. doi:10.1103/PhysRevLett.81.1786. URL http://link.aps.org/doi/10.1103/PhysRevLett.81.1786.

[BABAR(2009)] BABAR. Measurement of time dependent cp asymmetry parameters in B0

meson decays to ωK0S , η′

K0

, and

π0

K0S . PRD, 79:052003, 2009. doi: 10.1103/PhysRevD.79.052003. URL

http://link.aps.org/doi/10.1103/PhysRevD.79.052003.

[Belle(2007)] Belle. Observation of time-dependent cp violation in B0 → η

′K

0decays and improved measurements of cp

asymmetries in B0 → ϕK

0, K

0S K

0S K

0S and B

0 → j/ψK0

decays. PRL, 98:031802, 2007. doi:10.1103/PhysRevLett.98.031802. URL http://link.aps.org/doi/10.1103/PhysRevLett.98.031802.


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http://link.aps.org/doi/10.1103/PhysRevD.74.014003


http://dx.doi.org/10.1007/JHEP10%282014%29165

http://link.aps.org/doi/10.1103/PhysRevLett.81.1786


http://link.aps.org/doi/10.1103/PhysRevLett.98.031802

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