sin(2β/2Φ1) Measurements
Riccardo de Sangro INFN - Frascati
FPCP May 19-24, 2013
sin(2 /2 1 ) Measurements Riccardo de Sangro INFN - Frascati FPCP - - PowerPoint PPT Presentation
sin(2 /2 1 ) Measurements Riccardo de Sangro INFN - Frascati FPCP May 19-24, 2013 Outline Introduction Recent Experimental results on B c c s B q q s B c c d Future prospects Summary 2 R. de
Riccardo de Sangro INFN - Frascati
FPCP May 19-24, 2013
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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May 19-24, 2013 FPCP 2013 - Buzios, Brasil 3
Bd Unitary Triangle
Unitarity rela=on for Bd decays
Experimental access to β via TD B(B) decay rate to same final CP eigenstate with eigenvalue η (assuming ΔΓ=0):
! P
Stag ðtÞ ¼ ejtj=b
4b ½1 þ StagS sinðmdtÞ þ StagC cosðmdtÞ; C¼1jj2 1þjj2; S ¼2=mðÞ 1þjj2 ; ¼ q p
A; parameter Stag ¼ þ1ð1Þ
¼ þ ð a B0 ( B0),
when the tag B is tagged as CPV parameters:
f f
1) is the CP eigenvalue for a CP-even (odd)
while ¼ 1 indicates
CPV in mixing Negligible in B (~10-3) ⇒ q/p ~1 CPV in decay (direct CP)
with different w n |Af/Af| = 1)
May 19-24, 2013 FPCP 2013 - Buzios, Brasil 4
For b→ccs “Golden Modes” Negligible penguin, theoretically clean prediction: Sη = -ηsin(2β), C=0
Penguin
Theore=cally clean as only the tree level process dominates the
J/$ K0 B0 B0
Interference
)
2
(GeV/c
ES
m
5.2 5.22 5.24 5.26 5.28
2
Events / 2 MeV/c
1000 2000
)
2
(GeV/c
ES
m
5.2 5.22 5.24 5.26 5.28
2
Events / 2 MeV/c
1000 2000
S
K ψ J/ → B
S
(2S)K ψ → B
S
K
c1
χ → B
S
K
c
η → B a)
E (MeV) Δ
20 40 60 80
Events / 2 MeV
500 1000
E (MeV) Δ
20 40 60 80
Events / 2 MeV
500 1000
L
K ψ J/ → B b)
)
2
(GeV/c
ES
m
5.2 5.22 5.24 5.26 5.28
2
Events / 2 MeV/c
100 200
)
2
(GeV/c
ES
m
5.2 5.22 5.24 5.26 5.28
2
Events / 2 MeV/c
100 200
*0
K ψ J/ → B c)
R⊥ = 0.233 ± 0.010 (stat) ± 0.005 (sys) [PRD 76, 031102(R) (2007)]
Experimentally clean as well !
May 19-24, 2013 FPCP 2013 - Buzios, Brasil 5
Tree “only”
measurement at hadron collider
(Phys. Lett. B 721, 2013)
from a single experiment
(PRL 108 (2012) 171802)
b→ccs
Sccs=-ηsin2β
as only the tree lev
J/$ K0
May 19-24, 2013 FPCP 2013 - Buzios, Brasil 5
Tree “only”
measurement at hadron collider
(Phys. Lett. B 721, 2013)
from a single experiment
(PRL 108 (2012) 171802)
b→ccs
Sccs=-ηsin2β
Penguin dominated modes
PRD 85 (2012) 054023
B0→K+K-Ks
PRD 85 (2012) 112010
b s q q
S
b→qqs
Sqqs=sin2βeff
as only the tree lev
J/$ K0
May 19-24, 2013 FPCP 2013 - Buzios, Brasil 5
Tree “only”
measurement at hadron collider
(Phys. Lett. B 721, 2013)
from a single experiment
(PRL 108 (2012) 171802)
b→ccs
Sccs=-ηsin2β
Penguin dominated modes
PRD 85 (2012) 054023
B0→K+K-Ks
PRD 85 (2012) 112010
b s q q
S
b→qqs
Sqqs=sin2βeff
Small penguin pollution
PRD 86 (2012) 071103(R)
partial reconstruction
PRD 86 (2012) 112006
b→ccd
Sccd=sin2βeff
as only the tree lev
J/$ K0
May 19-24, 2013 FPCP 2013 - Buzios, Brasil 5
Tree “only”
measurement at hadron collider
(Phys. Lett. B 721, 2013)
from a single experiment
(PRL 108 (2012) 171802)
b→ccs
Sccs=-ηsin2β
Penguin dominated modes
PRD 85 (2012) 054023
B0→K+K-Ks
PRD 85 (2012) 112010
b s q q
S
b→qqs
Sqqs=sin2βeff
Small penguin pollution
PRD 86 (2012) 071103(R)
partial reconstruction
PRD 86 (2012) 112006
b→ccd
Sccd=sin2βeff
as only the tree lev
J/$ K0
Measure S,C in these processes to test SM prediction and look for new physics (NP)
C,S ~same in SM
May 19-24, 2013 FPCP 2013 - Buzios, Brasil 6
(~ 385 10 of each , , , ) B B B B
(4S) e e BB
(~ 235 10 of each , , , ) B B B B
and
pp bbX
( 20 10 of each , , , ) B B B B
...more coming
May 19-24, 2013 FPCP 2013 - Buzios, Brasil 7
Tagging & Time measurement
BB pair from Y(4S) decay with (slight) boost to allow Δt measurement.
constraints
events
Signal Selection CPV Asymmetry Fit
May 19-24, 2013 FPCP 2013 - Buzios, Brasil 8
Opposite Side Same Side
b b̅ d d̅ u
Bd
KS J/ψ μ μ π πSignal
π+
SS Pion
b ➝ c ➝ s b ➝ X l-
VTX OS Muon OS Electron
l- K-
OS Kaon
associated b hadron
reconstruction
hadronization
mesons
Julian Wishahi | Δ
LHCb Decay time [ps]
0.1 0.2
Candidates / (5 fs)
1000 2000 3000 4000 5000 6000 7000
LHCb
inary* Preliminary*
~45 fs time resolution (from prompt J/ψ) 1(+2) fb-1 integrated luminosity
εtagD2 ≈ 2.3% ω ≈ 36.7%
Tagger εtag % ω % εtagD2 % µ 5.20±0.04 30.8±0.4 0.77±0.04 e 2.46±0.03 30.9±0.6 0.36±0.03 K 17.67±0.08 39.33±0.24 0.81±0.04 Qvtx 18.46±0.08 40.31±0.24 0.70±0.04
~30% at B-Factories OS tagger performance
incoherent production σ(bb)≈75 µb at √s=7 TeV 2 < η < 6
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with J/ψ→µ+µ- and Ks→π+π-
asymmetry in pp collisions
to cancel detector asymmetries
Good agreement with B-Factories results, error ~ x3 that of B factories
[Phys. Lett. B 721, 2013]
S = 0.73 ± 0.07 (stat) ± 0.04 (syst),
CJ/ψ K0
S = 0.030 ± 0.089
0.091 (stat) ± 0.012 (syst),
S, CJ/ψ K0 S) = 0.416.
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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Events / 0.5 ps 50 100 150 200 250 300 350 400 t (ps) ∆
2 4 6 Asymmetry
0.2 0.4 0.6 Events / 0.5 ps 50 100 150 200 250 t (ps) ∆
2 4 6 Asymmetry
0.2 0.4 0.6
1k 2k 3k 5.2 5.22 5.24 5.26 5.28 5.3
All combined B0→J/ψKS B0→ψ(2S)KS B0→χc1KS Fit result
(a)
Mbc (GeV/c2) Events / 1 MeV/c2
Data B0→J/ψKL real J/ψ, real KL real J/ψ, fake KL fake J/ψ
(b)
pB* (GeV/c) Events / 50 MeV/c
1k 2k 3k 4k 5k 0.4 0.8 1.2 1.6 2
TABLE I. CP eigenvalue (f), signal yield (Nsig), and purity for each B0 ! fCP mode. Decay mode f Nsig Purity (%) J=c K0
S
1 12 649 114 97 c ð2SÞð‘þ‘ÞK0
S
1 904 31 92 c ð2SÞðJ=c þÞK0
S
1 1067 33 90 c1K0
S
1 940 33 86 J=c K0
L
þ1 10 040 154 63
þ0:642 0:047 0:021 þ0:667 0:023 0:012 þ sin21 fSf
Af þ
012 þ0:006 0:016 0:012
Best measurement from a single experiment!
[PRL 108, 171802 (2012)]
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b s q q
in the values of S and C. Definitions:
g s b b s ~ ~ ~
( )LR
d 23
δ
penguins”
phase is the same as that of b→ccs: S=-ηsin2β, C=0
s
SM
ΔS
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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analysis
KS is long lived ⇔ no tracks emerge from the B decay vertex
0:94þ0:24
0:21 0:06
the first quoted uncertainty
be S ¼
and C ¼ 0:17 0:18 0:04,
[PRD 85, 054023 (2012)]
S
C
0.5 1 2 3 4 5
First evidence of CPV (3.8σ)! b→ccs
16 15 13 12
201 62 ± ±
Signal yields: B0→3K0
S(π+π-) (Purity = 40%)
B0→2K0
S(π+π-) K0 S(π0π0)
CL contours SCP (=-ηS)
Most recent Belle PRL 98 (2007) 031802
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
eigenstate
separate intermediate (resonant) CP eigenstates
trigonometric ambiguity on β from sin2β measurement
which has small theoretical uncertainty
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plitudes: m2
13
m2
23
spin=0 spin=1 spin=2
3 13 23
d p dm dm E ∝
“Cartoon” DP
Superimposed resonant contributions
P→p1p2p3
! Interference ! access to phases
with no ambiguity such as sin2β eff = sin(180° - 2β eff)
[PRD 85, 112010 (2012)]
See also most recent Belle: PRD 82 (2010) 073011
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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[PRD 85, 112010 (2012)]
A ~ Σ ci F(m2
13,m2 23)
A ~ Σ ci F(m2
13,m2 23)
F=functions describing amplitue (e.g. Breit-Wigner) ci=complex, “isobar amplitudes”
TD Amplitude
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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Nsig = 1579±46 (Purity = 18%) BF = (25.4±0.9±0.8)×10-6 [χc0K excluded] βeff(ϕKS) = (21±6±2)° ← most precise βeff(f0KS) = (18±6±4)° βeff(non-ϕ, non-f0) = (20.3±4.3±1.2)° 90°-βeff excluded at 4.8σ (ambiguity in J/ψKS) Agree with SM
Component ð1020ÞK0
S
f0ð980ÞK0
S
Other ACPð¼ CÞ ð%Þ S 5 18 5 0:66 0:17 0:07 28 24 9 0:55 0:18 0:12 2 9 3 0:65 0:12 0:03
) tly degenerate in β) Agree
[PRD 85, 112010 (2012)]
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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May 19-24, 2013 FPCP 2013 - Buzios, Brasil
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
the angular momentum of the decay products
measuring the CP-odd fraction R⊥ and the time dependent CP asymmetry
Full TD amplitude CP=+1 for A||,A0 CP=-1 for A⊥
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“Transversity basis”
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
Entries / ps
0.8 0.6 0.4 0.2
5 20 40 60 80 100
raw asymmetry t (ps)
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[PRD 86 (2012) 071103(R)]
BðB0!DþDÞ ¼ ½7:82 0:38ðstatÞ 0:63ðsystÞ 104; R0 ¼ 0:624 0:029ðstatÞ 0:011ðsystÞ; R? ¼ 0:138 0:024ðstatÞ 0:006ðsystÞ; S ¼ 0:79 0:13ðstatÞ 0:03ðsystÞ; and A ¼ 0:15 0:08ðstatÞ 0:04ðsystÞ:
1st Observation >5σ !
(GeV)
bcM
5.24 5.26 5.28 5.30
Events / ( 0.00175 GeV )
50 100 150 200 250 300
a) E (GeV) ∆
0.0 0.1
Events / ( 0.007 GeV )
50 100 150 200 250
b)
Also results on D(*)D final states: [PRD 85, 091106(R)]
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
component CPV parameters S+ and C+, and the fraction R⊥ of CP-odd amplitude:
which are related to C+ and S+ by the relations C=C+ and S=S+(1-2R⊥)
Analysis Method Partial Reconstruction
Partial Reconstruction Method
with the D0 decaying to one of 4 modes
consistent with a B0 decaying to a D*-D0π combination with a missing D0
R⊥=0.158±0.028±0.006
B0 “tag” Y(4S) B0 “CP”
un-reconstructed D*, use only slow pion
π∓s
D0 D±* D0
Kπ Kππ0 K3π Ksπ+π- π±
Fully reconstructed D*
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[PRD 86 (2012) 112006]
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
Kaon Tags
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[PRD 86 (2012) 112006]
recoil mass (GeV/c^2)
1.84 1.845 1.85 1.855 1.86 1.865 1.87
Events / ( 0.001 GeV/c^2 )
200 400 600 800 1000 1200 1400 1600 1800 2000
mRec - On Peak
fisher 15
0.5 1 1.5 2 2.5 3 3.5 4
Events / ( 0.04 )
200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
Fisher15 - on Peak
recoil mass (GeV/c^2)
1.84 1.845 1.85 1.855 1.86 1.865 1.87
Events / ( 0.001 GeV/c^2 )
10 20 30 40 50
mRec - Off Peak
fisher 15
0.5 1 1.5 2 2.5 3 3.5 4
Events / ( 0.0625 )
10 20 30 40 50 60 70
Fisher15 - off Peak
BB qq Signal Sum
Kin Fit Result - DATA
mrec F mrec F
delta t (ps)
2 4 6 8
Events / ( 1 ps )
200 400 600 800 1000 1200 1400 1600 1800 2000 2200
delta t (ps)
2 4 6 8
Events / ( 1 ps )
200 400 600 800 1000 1200 1400 1600 1800 2000 2200
Dt
2 4 6 8
Asymmetry
0.05 0.1 0.15 0.2 0.25
Dt
2 4 6 8
Asymmetry
0.05 0.1 0.15 0.2 0.25
B0 B0
Δt Fit Result and Raw Asymmetry
Δt (ps) Δt (ps)
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
Results Extraction of S+,C+
from R⊥
All errors are statistical + systematic
BABAR preliminary
C = C+ S = S+ (1 − 2R⊥) , R⊥ = 0.158 ± 0.02 Assuming negligible penguin contributions, then S+=-S-, and: and using[1]: This result is compatible with previous BaBar[1] and Belle[2] measurements and in agreement with SM predictions
[1] B. Aubert et al. (BABAR collaboration), Phys. Rev. D79, 032002 (2009) ; [2] B. Vervink et al. (Belle collaboration), Phys. Rev. D80, 111104 (2009).; Belle Collab. EPS 2011 Preliminary
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[PRD 86 (2012) 112006]
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from ccs to by ~x10
Mode Current Precision Predicted Precision (75 ab1) Discovery Potential
∆Sf(Th.)
∆Sf(Th.) 3 5 J/ K0
S
0.022 0.010 0 ± 0.01 0.002 0.005 0 ± 0.001 0.02 0.03 ⌘0K0
S
0.08 0.02 0.015 ± 0.015 0.006 0.005 0.015 ± 0.015 0.05 0.08 K0
S⇡0
0.28 0.01
S
0.18 0.04 0 ± 0.02 0.012 0.003 0 ± 0.02 0.07 0.12 K0
SK0 SK0 S
0.19 0.03 0.02 ± 0.01 0.015 0.020 0.02 ± 0.01 0.08 0.14 K0
S
0.26 0.03 0.03 ± 0.02 0.020 0.005 0.03 ± 0.02 0.09 0.14 ⇡0K0
S
0.20 0.03 0.09 ± 0.07 0.015 0.015 0.09 ± 0.07 0.21 0.34 !K0
S
0.28 0.02 0.1 ± 0.1 0.020 0.005 0.1 ± 0.1 0.31 0.51 K+KK0
S 0.08
0.03 0.05 ± 0.05 0.006 0.005 0.05 ± 0.05 0.15 0.26 ⇡0⇡0K0
S
0.71 0.08
S
0.28 0.07 0.13 ± 0.16 0.020 0.017 0.13 ± 0.16 0.41 0.69 J/ ⇡0 0.21 0.04
0.16 0.03
0.36 0.05
(*) 2011
SuperB Factory - B. Meadows, et al. [arXiv:1109.5028v2, Oct 2011]
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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from ccs to by ~x10
Mode Current Precision Predicted Precision (75 ab1) Discovery Potential
∆Sf(Th.)
∆Sf(Th.) 3 5 J/ K0
S
0.022 0.010 0 ± 0.01 0.002 0.005 0 ± 0.001 0.02 0.03 ⌘0K0
S
0.08 0.02 0.015 ± 0.015 0.006 0.005 0.015 ± 0.015 0.05 0.08 K0
S⇡0
0.28 0.01
S
0.18 0.04 0 ± 0.02 0.012 0.003 0 ± 0.02 0.07 0.12 K0
SK0 SK0 S
0.19 0.03 0.02 ± 0.01 0.015 0.020 0.02 ± 0.01 0.08 0.14 K0
S
0.26 0.03 0.03 ± 0.02 0.020 0.005 0.03 ± 0.02 0.09 0.14 ⇡0K0
S
0.20 0.03 0.09 ± 0.07 0.015 0.015 0.09 ± 0.07 0.21 0.34 !K0
S
0.28 0.02 0.1 ± 0.1 0.020 0.005 0.1 ± 0.1 0.31 0.51 K+KK0
S 0.08
0.03 0.05 ± 0.05 0.006 0.005 0.05 ± 0.05 0.15 0.26 ⇡0⇡0K0
S
0.71 0.08
S
0.28 0.07 0.13 ± 0.16 0.020 0.017 0.13 ± 0.16 0.41 0.69 J/ ⇡0 0.21 0.04
0.16 0.03
0.36 0.05
(*) 2011
SuperB Factory - B. Meadows, et al. [arXiv:1109.5028v2, Oct 2011]
improvement of the experimental precision on ΔS by ~x10 on several b→qqs channels, to match (present) theory accuracy
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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from ccs to by ~x10
Mode Current Precision Predicted Precision (75 ab1) Discovery Potential
∆Sf(Th.)
∆Sf(Th.) 3 5 J/ K0
S
0.022 0.010 0 ± 0.01 0.002 0.005 0 ± 0.001 0.02 0.03 ⌘0K0
S
0.08 0.02 0.015 ± 0.015 0.006 0.005 0.015 ± 0.015 0.05 0.08 K0
S⇡0
0.28 0.01
S
0.18 0.04 0 ± 0.02 0.012 0.003 0 ± 0.02 0.07 0.12 K0
SK0 SK0 S
0.19 0.03 0.02 ± 0.01 0.015 0.020 0.02 ± 0.01 0.08 0.14 K0
S
0.26 0.03 0.03 ± 0.02 0.020 0.005 0.03 ± 0.02 0.09 0.14 ⇡0K0
S
0.20 0.03 0.09 ± 0.07 0.015 0.015 0.09 ± 0.07 0.21 0.34 !K0
S
0.28 0.02 0.1 ± 0.1 0.020 0.005 0.1 ± 0.1 0.31 0.51 K+KK0
S 0.08
0.03 0.05 ± 0.05 0.006 0.005 0.05 ± 0.05 0.15 0.26 ⇡0⇡0K0
S
0.71 0.08
S
0.28 0.07 0.13 ± 0.16 0.020 0.017 0.13 ± 0.16 0.41 0.69 J/ ⇡0 0.21 0.04
0.16 0.03
0.36 0.05
(*) 2011
SuperB Factory - B. Meadows, et al. [arXiv:1109.5028v2, Oct 2011]
improvement of the experimental precision on ΔS by ~x10 on several b→qqs channels, to match (present) theory accuracy
and charged Bd,s decays will lead to theory improvement as well
May 19-24, 2013 FPCP 2013 - Buzios, Brasil
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[arXiv:1109.5028v2] Jul 2011
Observable/mode Current LHCb SuperB Belle II LHCb upgrade theory now (2017) (2021) (2021) (10 years of running) now 5 fb1 75 ab1 50 ab1 50 fb1 α from uud 6.1 5a 1 1
b
1 − 2 β from ccs (S) 0.8 (0.020) 0.5 (0.008) 0.1 (0.002) 0.3 (0.007) 0.2 (0.003) clean S from Bd → J/ψπ0 0.21 0.014 0.021 (est.) clean S from Bs → J/ψK0
S
? ? clean
5 ab−1 50 ab−1 ∆S ∆A ∆S ∆A φK0 0.073 0.049 0.029 0.018 η′K0 0.038 0.026 0.020 0.012 K0
SK0 SK0 S
0.105 0.067 0.037 0.024
Table 4: Current and projected precisions of the key observables in b → sqq decays.
Observable Current LHCb upgrade (50 fb−1) Theory uncertainty AU, V (B0
s → φφ)
0.04 (LHCb 1.0 fb−1) 0.004 0.02 [301] φeff
s (B0 s → φφ)
– 0.03 0.02 [298] φeff
s (B0 s → K∗0 ¯
K∗0) – 0.03 0.02 [298] sin 2βeff(B0 → φK0
S)
0.12 (B factories) 0.06 0.02 [178]
[arXiv 1208.3355v3] May 2013
Complementarity between LHCb and Belle2
[arXiv 1200.5012v1] Feb 2010
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