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

study for BelleII

Stefano Lacaprarastefano.lacaprara@pd.infn.it

INFN Padova

B2GM,Tsukuba, 21 June 2016

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 1 / 19

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 2 / 19

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 3 / 19

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)

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 4 / 19

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 5 / 19

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 6 / 19

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.

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 7 / 19

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 8 / 19

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 9 / 19

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)F past issues w/ variables “fixed”

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 studyI signal w/ machine background already produced

Next table numbers before Continuum Suppression cut

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 10 / 19

Background reduction (before CS cut)

Sample uu dd ss cc contiuum B0B0 B+B−

Input ev (M) 1284 321 306 1063 2974 2160 2070

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 13 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 smallI analyzed whole 5 ab−1 dataset from MC5

preliminary study on w/ machine background shows similar rates

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 11 / 19

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 12 / 19

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 13 / 19

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.

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

0S B2GM 21/06/2016 14 / 19

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

"bcA RooPlot of "M / ndf = 9.8172χ

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

E"∆A RooPlot of " / ndf = 1.0252χ

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

A RooPlot of "bdt" / ndf = 22.3482χ

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

10

20

30

40

50

60

t"∆A RooPlot of " / ndf = 1.0342χ

0.14± = 0.06 CPC

0.24± = -0.271 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

2

4

6

8

10

12

14

16

18

20

22

24

"bcA RooPlot of "M / ndf = 0.7522χ

0.00040 GeV± = 5.27838 µ 0.00035 GeV± = 0.00353 σ

69± = -90.0 ξ

0.37±n = 1.15 0.068± = 0.604 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

2

4

6

8

10

12

14

16

E"∆A RooPlot of " / ndf = 0.8682χ

0.014± = 0.500 Cf 0.0053 GeV± = -0.07049

Cµ

0.0060 GeV± = 0.0269 T

µ

0.00086 GeV± = 0.03000 Cσ 0.0057 GeV± = 0.0454 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

5

10

15

20

25

30

A RooPlot of "bdt" / ndf = 0.6522χ

0.020± = 0.110 µ 0.013± = 0.114 Lσ 0.012± = 0.096 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

200

400

600

800

1000

1200

1400

1600

1800

2000

t"∆A RooPlot of " / ndf = 0.9332χ

0.016 ps± = 0.029 CBias

0.087 ps± = 0.082 TBias

0.036± = 0.800 Cf

0.0018± = 0.0045 Of

0.037 ps± = 0.273 CScale

0.13 ps± = 1.45 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

20

40

60

80

100

120

140

"bcA RooPlot of "M / ndf = 0.8272χ

4.8± = -29.87 ξ 0.000099 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

20

40

60

80

100

120

140

E"∆A RooPlot of " / ndf = 1.1732χ

0.30± = -1.378 1

p

5.6± = -1.84 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

A RooPlot of "bdt" / ndf = 0.7332χ

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 15 / 19

Toy MC

Testing fit machinery with Toy MC;

Yield estimated for L = 300 fb−1: N(BB) ∼ 330 · 106

I width of distribution related to the expected statistical uncertainty;I check also for bias;I input CP asymmetry parameter: S=0.7 C=0.0I testing two different CS scenarios:

F TightF LooseF No cut

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 16 / 19

Toy results B0 → η′(→ ηγγπ+ π−)K0

S+−

L = 300 fb−1: 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

Toy results - dtSig_S Entries 1000

Mean 0.00572± 0.703

Std Dev 0.00405± 0.181

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

Toy results - dtSig_S Entries 1000

Mean 0.00563± 0.696

Std Dev 0.00398± 0.178

Toy results - dtSig_S

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 = 0.11

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 17 / 19

Toy results B0 → η′(→ η3ππ+π−)K0

S+−

Loose

L = 300 fb−1: 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

Toy results - dtSig_S Entries 995

Mean 0.0105± 0.708

Std Dev 0.00742± 0.33

Toy results - dtSig_S

Preliminary results:Par Bias RMS

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

Less events due to lower BRand reduced efficiency

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

BaBar (467 · 106 BB): Nsig = 105, σS = 0.26, σC = 0.20

1including also η′ → ρ0γS.Lacaprara (INFN Padova) B

0 → η′K

0S B2GM 21/06/2016 18 / 19

Summary

Almost a complete analysis chain for sensitivity study for ��CP inB0 → η ′K0

S channel;

Presente at last B2TIP workshop;

preliminary results are encouraging;I comparison with Belle and BaBar results looks fine;

many thing to do:I include machine background (in progress)I 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 . . .

manpower: a new postDoc student from Padova, Alessandro Morda, isjoining me for this work at ∼ 50%

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 19 / 19

Additional stuff

Additional or backup slides

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 1 / 17

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 )

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 2 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 3 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 4 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 5 / 17

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 )

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 6 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 7 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 8 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 9 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 10 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 11 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 12 / 17

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 %

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 13 / 17

Toy results B0 → η′(→ ηγγπ+ π−)K0

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

Toy results - dtSig_S Entries 1000

Mean 0.0079± 0.703

Std Dev 0.00559± 0.25

Toy results - dtSig_S

0.6− 0.4− 0.2− 0 0.2 0.4 0.60

10

20

30

40

50

60

70

80

Toy results - dtSig_C Entries 1000

Mean 0.00539± 0.0103

Std Dev 0.00381± 0.17

Toy results - dtSig_C

0 50 100 150 200 250 300 350 4000

20

40

60

80

100

120

140

Toy results - nSig Entries 1000

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 14 / 17

Toy results B0 → η′(→ ηγγπ+ π−)K0

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

Toy results - dtSig_S Entries 1000

Mean 0.00572± 0.703

Std Dev 0.00405± 0.181

Toy results - dtSig_S

0.6− 0.4− 0.2− 0 0.2 0.4 0.60

10

20

30

40

50

60

70

80

90

Toy results - dtSig_C Entries 1000

Mean 0.00441± 0.00198

Std Dev 0.00312± 0.139

Toy results - dtSig_C

0 100 200 300 400 500 600 700 8000

20

40

60

80

100

120

Toy results - nSig Entries 1000

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 15 / 17

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

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 16 / 17

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.

S.Lacaprara (INFN Padova) B0 → η

′K

0S B2GM 21/06/2016 17 / 17