to (to ) time dependent cp-8.5-.25ex sensitivity study for...
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B0 → η′(→ ηπ+π−)K0S Time Dependent ��CP sensitivity
study for BelleII
Stefano [email protected]
INFN Padova
B2TIP workshop,Pittsburgh, 23 May 2016
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 1 / 21
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 B2TIP 24/05/2016 2 / 21
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 B2TIP 24/05/2016 3 / 21
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 B2TIP 24/05/2016 4 / 21
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 B2TIP 24/05/2016 5 / 21
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 B2TIP 24/05/2016 6 / 21
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 B2TIP 24/05/2016 7 / 21
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 B2TIP 24/05/2016 8 / 21
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 B2TIP 24/05/2016 9 / 21
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 B2TIP 24/05/2016 10 / 21
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
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 11 / 21
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
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 12 / 21
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 B2TIP 24/05/2016 13 / 21
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
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 14 / 21
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
BDT > −0.055, εsignal = 95%, (1− εbackground ) = 58%,
todo: no cut, but include the BDT in the likelihood not yet
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 15 / 21
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. not yet
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 B2TIP 24/05/2016 16 / 21
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 "
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 "
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
"bcA RooPlot of "M / ndf = 0.3282χ
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
E"∆A RooPlot of " / ndf = 0.4242χ
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 "
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
"bcA RooPlot of "M / ndf = 1.1232χ
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
E"∆A RooPlot of " / ndf = 1.0232χ
0.20± = -1.256 1
p
3.8± = 0.5 2
p
E"∆A RooPlot of "
Contin
uum
∆T Mbc ∆EStill problem to fit the continuum suppression variable: very spiky
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 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
Partially embedded toysI Signal and SXF from MC;I Continuum and Peaking background from pdf;
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 18 / 21
Toy results B0 → η′(→ ηγγπ+ π−)K0
S+−
L = 300 fb−1, N(BB) ∼ 330 · 106:Nsig = 390, Nsxf = 14, Ncont = 1400, Npeak = 23
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 25.4Prelim
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 B2TIP 24/05/2016 19 / 21
Toy results B0 → η′(→ η3ππ+π−)K0
S+−
Loose CS
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
Toy results - dtSig_S Entries 995
Mean 0.0105± 0.708
Std Dev 0.00742± 0.33
Toy results - dtSig_S
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
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 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.
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 21 / 21
Additional stuff
Additional or backup slides
S.Lacaprara (INFN Padova) B0 → η
′K
0S B2TIP 24/05/2016 1 / 14
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 B2TIP 24/05/2016 2 / 14
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 B2TIP 24/05/2016 3 / 14
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 B2TIP 24/05/2016 4 / 14
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 B2TIP 24/05/2016 5 / 14
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 B2TIP 24/05/2016 6 / 14
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 B2TIP 24/05/2016 7 / 14
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 B2TIP 24/05/2016 8 / 14
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 B2TIP 24/05/2016 9 / 14
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 B2TIP 24/05/2016 10 / 14
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 B2TIP 24/05/2016 11 / 14
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 B2TIP 24/05/2016 12 / 14
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 B2TIP 24/05/2016 13 / 14
Bibliography I
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[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 B2TIP 24/05/2016 14 / 14