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Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 1
Mid-Term at the B Factories : the New Picture of CP Violation
Andreas HöckerLaboratoire de l’Accélérateur Linéaire, Orsay
Seminar
E.P.F. Lausanne, February 14, 2005
hoecker@lal.in2p3.fr
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 2
1. The Universe is empty* !
2. The Universe is almost empty* ! ( )baryon baryon baryon 10
~ 10n nn
On nγ γ
−−∆
=
Sakharov rules (1967) to explain Baryogenesis1. Baryon number violation 2. CP violation3. No thermic equilibrium (non-stationary system)
Why CP Violation?
Bigi, Sanda, « CP Violation » (2000)Initial condition ?
Dynamically generated ?
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 3
CP Violation is flavor physics
Discovery of CP violation (1964)
The smallness of KL → µ+µ– predicts charm quark (GIM)
KM theory (to describe CP violation) predicts third quark generation
∆mK = m(KL) – m(KS) predicts mass of charm quark
Frequency of B0B0 mixing (∆mB) predicts heavy top quark
What’s next ???
V.L. Fitch R. Turlay J.W. Cronin J.H. Christenson
PRL 13, 138 (1964) [cited: 1007 times]
Moments of glory in flavor physics :
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 4
(parenthesis)
Evolution of working conditions (example BABAR) :
PRL 87, 091801 (2001) [cited: 280 times]
… we are 593 physicists !
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 5
The Search for New Physics in the B System
see, e.g., the instructive talk by Yuval Grossman at LP’03: hep-ph/0310229
6
4NP
(10 ) for , ~ ~
(10 ) for , Qq tQ tq
W
V V O Q s q dm O Q b q d
δ ∗ −
−
⎧ = =⎪⎨Λ = =⎪⎩
Since the successful and precise measurement of sin2β in decays (in perfect agreement with the SM), there is considerable effort at B Factories towards the search for specific signs of New Physics (NP)…. WHY ?
b ccs→
The gauge hierarchy Problem (Higgs sector, scale ~ 1 TeV)
Baryogenesis (CKM CPV too small)
The strong CP Problem (why is θ ~ 0 ?)
Grand Unification of the gauge couplings
... many more
Conflict between limits from flavor physics ? 1 TeV (e.g., K0, D0, B0 mixing), and NP scale (1 TeV) NP cannot have a generic flavor structure
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 6
New Physics: some possibilities
MFV models (minimal flavor violation) : CP violation is completely governed by CKM
precision tests in rare processes
Q : why ?
The NP is essentially flavor blind up to large scales
test of CP violation in flavor conserving processes (EDM, …)
Q : and what about the leptons ?
Intermediate solutions (example : only b→s is affected by low energy NP), …
Q : why would these two families by special ?
… and other still unknown alternatives, which certainly will give the correct answer
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 7
The CKM Matrix and the Unitarity Triangle
αβγ
( )3 3 3
0ud ub cd cb td tbV V V V V V
A A Aλ λ λ
∗ ∗ ∗+ + =
∝ ∝ − ∝
d s b
u
c
t
CKMV =
Re
Im
td tbV V ∗
cd cbV V ∗
ud ubV V ∗
Re
Im
1 0ud ub td tb
cd cb cd cb
V V V VV V V V
∗ ∗
∗ ∗+ + =
iρ η+
( , )ρ η
(1,0)
phase invariant :
ud us ub
cd cs cb
td ts tb
V V VV V VV V V
W –
QqVqQ
Q → q
Bob
Cah
n
J/2
Jarlskog invariant J = 0 ⇔ no VCP Jarlskog, PRL 55, 1039 (1985)
CP Violation(Im[...] ≠ 0)
arg(...) γ≈
arg(...) β≈
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 8
The Bd System (e+e– →ϒ(4S) factories)
( )0 0, ( )1,0
( )ρ,η
Re
Im
α
βγ
uR tR0 0
0 0
0 ( ) ( )( )
0 0
/ , ...
/
, ...
S
s
S
B J K
B JB D D
B K
ψ
ψπ
φ
∗ + ∗ −
→
→
→
→
0
( ) ( )
( )
0 0
0
, ...
( )
SK
S
B D KB D K
B DK
B D
π π
π ρ
+ −
∗ ∗
∗
∗
→
→
→
→
b ub c
νν
→→
l
l
0 , ,B ππ ρπ ρρ→
( )( ) /B B Kρ ω γ γ∗→ →
0 0 : dB B m↔ ∆
0ud ub cd cb td tbV V V V V V∗ ∗ ∗+ + =
the Bd is also accessible by the hadron machines !
b ccs→
b ccd→
b sss→
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 9
The Bs SystemATLASATLASATLAS CM
S
CCMM
SS
( )0 0, ( )1,0
( )ρ,η
Re
Im
γ ′
uR% tR%
0
0
/ , ...
, ...s
s
B J
B
ψφ
φφ
→
→
0
0
0 0
0
/
, ...
s s
s
s S
s s s
B D K
B K K
B J K
B D D
ψ
+ −
+ −
→
→
→
→
0 0 : /s s s dB B m m↔ ∆ ∆
0td ud ts us tb ubV V V V V V∗ ∗ ∗+ + =
δγ ~ 1°
the Bs is not accessible by the ϒ(4S) B factories!
0( )sB µ µ+ −→ 0 10(BR for ~ 2 10 )dB −×
0 9(BR for ~ 4 10 )sB −×
(hadron machines)
b ccs→
b sss→
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 10
Flavor Physics and the Search for CP Violation
Flavor Physics and the Search for CP Violation
ATLAS
Present and future - Worldwide Program :
BTEV
NA48CLEO-c
E787/949
???
KEK / J-PARC
0 0LK
Kπ νν
π νν+ +
→
→
+ neutron EDM experiments: ILL (Grenoble), PSI (Zürich), Los Alamos, ...
Super-BABAR ?Super-B ?
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 11
After the B physics pioneers : Argus, CLEO and the LEP experiments ...The B Factories : PEP-2 (SLAC) and KEK-B (KEK, Japan)
SLD (& MARK II)
BABAR
Fixed target experiments
Linac
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 12
coherent production of neutral B pair
boost of ϒ(4S) in the laboratory : βγ = 0.56
e–
e+
+ − → ϒ →(4 )e e S BB
Asymmetric-Energy B Factory : PEP-II
Quantum coherence : at ∆t = 0, the system is a superposition of :
one and one0B 0Bone and oneHB LB
one and one1CPB =+ 1CPB =−
Einstein-Podolsky-Rosen phenomenon : measurement of flavor of one meson determines flavor of other meson at same proper time; this property is exploited for the “flavor tagging”
9 GeV e– against 3.1 GeV e+ :
3 km
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 13
July 31, 2004
3 × design
PEP-II Luminosity
Peak luminosity 0.92×1034 cm–2s–1
Best shift 246.3 pb–1
Best month 16.7 fb–1
Best 30 days 17.0 fb–1
BABAR logged 264.4 fb–1
710.5 pb–1
4.5 fb–1
Best day
Best 7 days
PEP-II records :
~245 million BB pairs recorded
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 14
PEP-II : ~5 Hz continuousKEKB : every ~5-10 min
Best shift, without trickle Inj.
Best shift, LER trickle Inj.
Best shift, LER + HER trickle Inj.
“Trickle Injection”
Nov 2003
Mar 2004
PEP-II LumiHER current LER current
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 15
e+ (3.1GeV)
e– (9 GeV)
The BABAR Detector
1.5 T solenoid EMC6580 CsI(Tl) crystals
Drift Chamber40 stereo layers
Instrumented Flux Returniron / RPCs (muon / neutral hadrons)
Silicon Vertex Tracker5 layers, double-sided strips
DIRC (PID)144 quartz bars
11000 PMTs
BABAR, NIM A479, 1 (2002 )
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 16
Particle Identification : the Čerenkov Detector (DIRC)
tracks penetrating the radiators
Simulated Čerenkov ring
Hits measured by PMTs
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 17
Summary of Summary of ICHEPICHEP 2004 Results2004 Results
Measurements of |Vub| and |Vcb| [ appendix ]β :
sin2β and cos2β with B0 → charmonium K0
sin2β with « penguin » modesDirect CP Violation (B0 → K+π –)α :
B0 → π +π –
B0 → ρ +ρ –
B0 → (ρ π)0
γ :methods/measurements with charged B’smethods/measurements with neutral B’s
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 18
β
Measurement of the angle Measurement of the angle ββ—— and the search for New Physicsand the search for New Physics ——
[∆B=2]
b
btt
W
W0B 0Bd
d
[∆B=2]
b
d b
dt
tWW0B 0B
( )2arg 2td tbV V β∗ ≈ −
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 19
The three CP-Violation phenomena
Condition for CP invariance :
CP invariance requires :
Classification of CP violation :
CP violation in mixing (”indirect”) :
CP violation in the decay (“direct”) :
CP violation in interference between mixing and decay :
220 0( ) ( ) , CP CPf H B t f H B t t= ∀
/ 1
/ 1
Im 0CP CP
CP
f f
f
q p
A A
λ
=
=
=1
CPfλ = ±
| / | 1q p ≠
phén
omèn
esde
VC
P
{ } { }1 1, ,L H CP CPB B B B=+ =−=
Definition of “CP parameter” :
2ie β−≈
CP
CP CP
CP
ff f
f
Aqp A
λ η= ⋅
CP eigenvalue
decay amplitude ratio
| | 1CPfλ ≠
Im 0CPfλ ≠
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 20
0 01 Prob( ( ) ) Prob( ( ) )CPf CP CPB t f B t fλ ≠ ± ⇔ → ≠ →
Time-dependent asymmetry observable
CP Violation due to the interference of decays with and without mixing
0 0
0 0
( ( ) ) ( ( ) )( )( ( ) ) ( ( ) )
sin( ) cos( )CP
P
C
C
P
CP CPf
CP P
d df
C
f
B t f B t fA tB t f B t f
m t C m tS
Γ → −Γ →=Γ → + Γ →
= ∆ − ∆
= 0= sin(2β ) for b → ccs, sssandwith :
2
/~ i
q pe β−
CP
mixing
decay
0t =
t0B
0B
CPfA
CPfA
CPf
avec:
Mixing-Induced CP Violation (3rd type)
[ ]
2
2
2
1
1
2Im
1
f
f
f
f
f
fS
Cλ
λ
λ
λ
+
=+
−=
CP
obse
rvab
les
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 21
Single weak phase:clean extraction of CP phase
no direct CPV:
The Golden Channel:
0 0, ,/ /( ) sin(2 ) sin( )
dS L S LBJ K J K
A t m tψ ψ
η β= − ⋅ ⋅ ∆
0,/
| | 1S LJ Kψ
λ =
2e
tb td cb cs
tb td cb cs Ki
V V V Vq A qp A V V V V p
β
∗ ∗
∗ ∗
−
⎛ ⎞= − ⎜ ⎟
⎝ ⎠= −
⊕*tbV
*cbV
csVcbV
*csVW
tdV*tbV
tdV
Wb
d
c
d
cs
ccsdb
d
0 0 0, /B B J Kψ→
2*cscb λAVV ⋅∝
top-quark dominates
bcs
d d
ct,c,ug
4
real
real
( )
cb cs
tb ts
ub us
V V
V V
V V Aγ λ
∗
∗
∗ → ∝ ⋅
Tree Diagram
“Penguins”
So that time-dependent asymmetry simplifies to a pure sinusoidal function:
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 22
∆z
0tagB
e+e−
−l
K −
0recB
Fully reconstructed
µ+
π −0SK
/J ψ π +
µ−
0 0rec flavB B= (flavor eigenstates) mixing, lifetime, ...0 0rec CPB B= (CP eigenstates) CP analysis
ϒ(4S)
∆t ≈ ∆z/⟨βγ ⟩c⟨∆z⟩ ≈ 250µm Flavor tagging
Quality : Q = 30.5 %
Coherent B0B0 production :
Experimental Technique
0recB
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 23
sin(2β ) with B0 to charmonium
stat syst
stat syst
sin2 0.722 0.040 0.023
| | 0.950 0.031 0.013
β
λ
= ± ±
= ± ±
1205fb 227M BB− ⇔
BABAR, hep-ex/0408127 (2004)
compatible with Belle (see later) and the Standard Model (indirect) :
CP-odd (J/ψ KS …) CP-even (J/ψ KL)
BABARBBAABBARARBABARBBAABBARAR
β = ±[CKM]sin2 0.73 0.13
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 24
Metrology of the CKM Matrix
β +−⎡ ⎤= °⎣ ⎦
1.6 1.523.3
Precision measurement :
Excellent agreement. But: ρ,η don’t tell us everything !
CKMfitter, hep-ph/0406184 (2004) UTfit, hep-ph/0408079 (2004)
Measurement of the sign of cos2β is a direct test of the SM : if SM ⇒ cos2β > 0
cos2β accessible through time-dependent angular correlations in
But :
with one ambiguity on sign …
induced by ambiguity on strong phase
Ambiguity can be lifted with analysis of interference pattern between S and P wave in (Kπ) system.
( )000*0*0 / πψ SKKKJB →→
β >cos(2 ) 0
β <cos(2 ) 0
cos(2 ) 0 at 89% C.L.β >
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 25
Both decays dominated by single weak phaseBoth decays dominated by single weak phase
b s
, ,u c t, ,g Z γ
tb tsV V∗
Penguin :
s
dd
s
Tree :
b
dd
W +cbV ∗
csV
φ
0K
c /J ψ
s0K
New Physics? 3×
0 0 0, , ,
2/ / /S L S L S L
icb csJ K J K J K
cb csB K
V Vq q ep V V p
βψ ψ ψ
λ η η∗
−∗
⎛ ⎞⎛ ⎞ ⎛ ⎞= ⋅ ⋅ =⎜ ⎟⎜ ⎟ ⎜ ⎟
⎝ ⎠ ⎝ ⎠⎝ ⎠
c
0 0 0, , ,
2~S L S L S L
itb tsK K K
tb tsB K
V Vq q ep V V p
βφ φ φλ η η
∗−
∗
⎛ ⎞⎛ ⎞ ⎛ ⎞= ⋅ ⋅⎜ ⎟⎜ ⎟ ⎜ ⎟
⎝ ⎠ ⎝ ⎠⎝ ⎠
b ccs→
b sss→
?β β=sin2 si[ n2 charmonium] [ -pingouin]s
Confronting Loop and Tree Decays
0B
0B
High virtual mass scales involved: believed to be sensitive to New Physics
decays are tree and penguin diagrams, with equal dominant weak phases
decays are pure “internal” and “flavor-singlet” penguin diagrams
b ccs→
b sss→
(7000 tagged events) (1500 tagged events)
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 26
why the hell do you call these Penguin diagrams?
They don’t look like penguins!
I’ve never seen a Feynman diagram
that looks like you ☺
a controversy …
mirror image of Richard Feynman
courtesy : G. Hamel de Monchenault (École de Gif, 2003)
Why « penguins » ?
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 27
Bro
nze
Silv
erG
old b
dgu
0B
d
ss
φ
W −
digression : Classification of the penguins One may identify golden, silver and bronze-plated s-penguin modes:
γλ∗ −∝ 4~ iub us uV V R e
b
dgt
0B
d
ss
s
W −γλ∗ −∝ 4~ i
ub us uV V R e 2~tb tsV V λ∗∝
W −bd
0B
d
uu
0', fη
s 0K
0K 0K
0', fη
0K
arbre suppr. de couleur
s
b
dgt
d
ss
s
W −
0B
2~tb tsV V λ∗∝
b
dgt
0B
d
ds
d
W −γλ∗ −∝ 4~ i
ub us uV V R e 2~tb tsV V λ∗∝
W −bd
0B
d
uu 0 0, ,π ρ ω
s 0K0 0, ,π ρ ω
0K
Naive (dimensional) uncertainties on sin2β
2( )~ 5%λΟ
~ 10%
2( / )~ 20%λ λΟ
Note that within QCD Factorization/SU(3) these uncertainties can be much smaller !
λ λΟ +2( (1 / ))qqf
arbre suppr. de couleur
φ
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 28
B0 → K+K–K0 bronze and B0 → KS KS KS new golden mode !!!
Note that:
if NP contributes significantly to CPV in loop decays, we naturally expect it to be different among the modes
averaging only meaningful in case of SM
digression : KKK0 modes
What about B0 → K+K–K0 and B0 → KS KS KS ?
b
d
0B K +
g
t
s
us
u
W − 2~tb tsV V λ∗∝
0Kds
K − b
d
0BK +
s
us
u
W −
0Kds
K −
γλ∗ −∝ 4~ iub us uV V R e
0( )K
:u d↔0( )K
0( )K
:u d↔0( )K
but : « popup » ss-bar dynamically disvafored with respect to popup uu-bar
is B 0 → K+K–K0 silver ?
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 29
s-penguin : comparison BABAR vs. Belle (I)
BABAR : s-penguin average at 2.9σ from sin2β [cc] (WA)
Belle : s-penguin average at 2.9σ from sin2β [cc] (WA)
ICHEP 2004
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 30
s-penguin : comparison BABAR vs. Belle (II)
New result
pre- Moriond2005
Moriond EW
BABAR,hep-ex/0502013
Averages:
BABAR : CL = 0.62
Belle : CL = 0.05
both : CL = 0.15
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 31
Compilation of s-penguin Modes
sin2 [ ] 0.726 0.037sin2 [ -peng] 0.41 0.07
ccsβ
β= ±= ±
sin(2β) : disagreement of 3.8σbetween charmonium and s-penguin (neglecting theor. errors) :
New Physics in b → s transitions? (δ23)RR ?
b s
s
dd
s φ
0K0B
23( )RRδ%×b% s%g%
HFAG: http://www.slac.stanford.edu/xorg/hfag/
A difference of about 0.05-0.25 (depending on the mode) is expected in the SM : 3.8σ ~3.0σ.
Theoretical errors
ICHEP 2004
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 32
Direct Direct CPCP ViolationViolation—— and the and the ““KKππ puzzlepuzzle”” ——
Bob
Cah
n
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 33
... CP invariance implies :CP-conjugated amplitudes :
define2 2
2 2
| | | |( ) ( )| | | |( ) ( )
f fCP
f f
A AB f B fAA AB f B f
−Γ → −Γ →≡ =
+Γ → + Γ →
( )
( )f
f
A A B f
A A B f
= →
= →| | | |f fA A=
2 ( )
j j
j jB f
i if j
j
i iijf
j
A a e e
A e a e e
θ φ
θ φξ ξ −− −
= ⋅
= ⋅
∑
∑CP
alters sign under CP(weak phase)
CP invariant (strong phase)jθ
jφ
( ) ( )( ) ( )co
sin s n
os
i
s c
i jij
CPi j i j i j
ij
i j i ja aA
a a
θ θ φ φ
θ θ φ φ
⋅=
⋅
− ⋅ −
− −
⋅
∑∑
Direct CP violation requiresat least two amplitudes withdifferent weak and strong phases
CP Violation in the Decay
“don’t expect direct CP violation in copious decays; rather look into rare modes”
Direct CP violation theorem :
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 34
bd d
W −
us K −
0B
Tree : Cabibbo-suppressed
u π +
b
d
W −
g, ,t c u
Penguin : dominant ?
0B
d
us
K −
u π +
4ub usV V
λ
∗∝
∝ 2tb tsV V
λ
∗∝
∝
Direct CP Violation : B0 →K+π –
b uus→
0
0
B KB K
π
π
− +
+ −
→
→
Flavor eigenstate :
sPlotB0→K−π+
B0→K+π−
Discovery of direct CP violation by BABARand Belle in 2004 :
0( ) 0.109 0.019CPA B K π+ −→ = − ±BABARBBAABBARAR
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 35
Do we Understand the B →ππ , Kπ System?
QCD FA
pQCD
SCETincluding the treatment of charming penguins by Ciuchini et al.
With conservative error treatment, only a data-driven fit is predictive
Is there a Kπ puzzle ?
“Color Transparency”
Several theoretical tools existent to describe non-leptonic B decays. All are based on the concept of Factorization.
Beneke et al, PRL 83, 1914 (1999); NP B675, 333 (03)
Keum et al, PLB 504, 6 (2001); PRD 67, 054009 (03)
Bauer et al, PRD 63, 114020 (2001); hep-ph/0401188
Buras et al, EPJ C32, 45 (2003)
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 36
α
Measurement of the angle Measurement of the angle αα—— using using charmlesscharmless B B decaysdecays ——
Interference of b → u decay amplitudes with B0B0 mixing
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 37
“Charmless” b → u Decays
If penguin is negligible
b uud→
bd d
W −
ud π −
0B u π +
b
d
W −
g, ,t c u
0B
d
ud π −
u π +
Principal modes :0
0
0
BBB
π π
ρ π
ρ ρ
+ −
±
+ −
→
→
→
m
2 2 2i i iub udh h h h h h h h
ub udB
V Vq e e ep V V
β γ αλ η η η+ − + − + − + −
∗− −
∗
⎛ ⎞⎛ ⎞= ⋅ = =⎜ ⎟⎜ ⎟
⎝ ⎠ ⎝ ⎠
Time-dependent CP observable
( ) sin( ) cos( )
sin( ) sin( )sin(2 )d dh h
d d
h h h h
h h
S CA t m t m
tS
t
m t mα+ − + − + −
+ −
= ∆
⋅
− ∆
= ∆ = ∆
2
2
| | 1
1 | |0
1 | |CP
h h
h hf
h h
C
λ
λλ
+ −
+ −
+ −
=
−= =
+!
1 for h h
hη π+ − = =
idea
lsc
enar
io
3ub udV V
λ
∗∝
∝ 3tb tdV V
λ
∗∝
∝ Not a CP eigenstate
Tree : dominant Penguin : competitive ?
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 38
eff
( )2
( )
2
1 | / ||1 | /
i i
i ih h h hB
ii
ih h
ih h
T PT P
P TP T
q e ep e e
eee
e
δ
γ β
γ β
αα
δ
α
α
λ η
η
λ
+ − + −
+ −
+ −
+−
+−
+− +−
+− +−
+− +−
+−
− +
+ −
++
−
+−
−
⎛ ⎞⎛ ⎞ += ⎜ ⎟⎜ ⎟ +⎝ ⎠ ⎝ ⎠
⎛ ⎞−= ⎜ ⎟−⎝ ⎠
≡ where
is the relative strong phaseP T
δ θ θ+− +−+− ≡ −
“Charmless” b → u Decays : realistic case
If “T” and “P” are of the same order of magnitude :[Note that T and P are complex amplitudes !]
2eff1 sin
( ) sin( ) cos( )
sin( ) cos(2 ) ( )
d dh h h h h h
h dh h dh
S C
C
A t m t
C
m t
m t m tα
+ + − + −
+ − + −
−
−
= ∆ − ∆
= ∆ − ∆⋅
2
2
| | 1
1 | |0
1 | |CP
h h
h hf
h h
C
λ
λλ
+ −
+ −
+ −
≠
−= ≠
+
!
Direct CP violation can occur :
real
istic
scen
ario
Time-dependent CP observable
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 39
α can be resolved up to an 8-fold ambiguity within [0,π]
Isospin Analysis for B →ππ , ρρ
Réfs. for SU(2) analyses : Gronau-London, PRL, 65, 3381 (1990), Lipkin et al., PRD 44, 1454 (1991), a.o.
13 unknowns– 7 observ.– 5 constraints– 1 glob. phase = 0 ☺
2 isospintriangles and one common side
B+–, Sππ , Cππ
B+0, ACP
B00, (S00), C00
α, T+–, P+–, T+0, P+0, T00, P00
AccountConstraintsObservablesUnknowns
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 40
π 0
BBAABBARARA B0 → π 0π 0 candidate
SU(2) – Crucial Ingredient : B →π 0π 0 (color-suppressed)
π 0π 0
π 0
0 0 0 6( ) (1.51 0.28) 10B π π −→ = ± ×B 0 0 0( ) 0.28 0.39CPA B π π→ = ± BABAR, hep-ex/0412037 Belle, hep-ex/0408100
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 41
BABAR, hep-ex/0501071
Results for B0→π +π –
Results for the time-dependent analysis :
BABAR (227m) Belle (152m) Average
–1.00 ± 0.21 ± 0.07
–0.58 ± 0.15 ± 0.07
Sππ –0.30 ± 0.17 ± 0.03 –0.61 ± 0.14
Cππ –0.09 ± 0.15 ± 0.04 –0.37 ± 0.11
BABAR, hep-ex/0501071 Belle, PRL 93 021601 (2004)
Bad agreement :
χ2 = 13.1 (CL = 0.0014 ⇒ 3.2σ)
Isospin analysis : eff 37α α− < ° (90% CL)
0.37 0.17r +− = ±
( )101236δ +− +−= − °
penguin / tree
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 42
A “surprise” : B0→ρ +ρ –
Isospin analysis :
Branching fractions for the B → ρρ system (WA) :
B+– = (30 ± 6)×10–6 , B+0 = (26.4 )×10–6 , B00 < 1.1×10–6 à 90% CL
Note that : a small B00/B+0 ratio requires small penguins ! [ But: P+– = 0 would mean that : B+-/B+0 = 2 ]
Experimental complication :
B → VV can have LVV=0,1,2, with CP(LVV=0,2) = +1 and CP(LVV =1) = –1
Nature’s great present : longitudinal polarization dominates almost no CP dilution
6.16.4+−
BABAR (123m)
Sρρ –0.19 ± 0.33 ± 0.11
Cρρ –0.23 ± 0.24 ± 0.14
eff 15α α− < ° (90% CL) 0.110.100.10r +− +−=
(...)δ +− = °
penguin / tree
BABAR, hep-ex/0407051,0412067
BBAABBARAR
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 43
Dalitz analysis of B0→ (ρπ )0 →π +π –π 0
Exploit interference between amplitudes contributing to B0 → π +π –π 0
to simultaneously determine α and the strong phases
ρ–π+
ρ+π–
ρ0π0
003 0
003 0
A f A f A f A
A f A f A f Aπ
π
+− −++ −
+− −++ −
= + +
= + +
Form factor for ρresonance (Breit-Wigner )
( / )
ab i ab ab
ab i ba ba
A e T Pq p A e T P
α
α
−= +
= +
with :
All contributions to A3π must be modeled !
( )
( ) ( )
2
3
23 3
3 3
223 3
sin
cos
2Im d
d
f m t
A A
A A
A mA t
π π
π π
π
π
π
∗
⎛ ⎞⎜ ⎟⎜ ⎟
∝ − ∆⎜ ⎟⎜ ⎟⎜ ⎟+ ∆⎜ ⎟⎝ ⎠
+
⎡ ⎤⎣ ⎦
−
Time dependence
Simultaneous fit of 16 bilinears (Ui , Ii )(27 in total, 9 parameters are insignificant, 1 unphysical phase)
Snyder-Quinn, PRD 48, 2139 (1993)
Decay amplitudes
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 44
∆χ2(no direct CPV) = 14.5 (CL = 0.00070 ⇒ 3.4σ)
From the 16 bilinears (Ui, Ii), we determine the physical parameters :
Results of the B0→ (ρπ )0 →π +π –π 0 Dalitz analysis
BABAR, hep-ex/0408099
Average : BABAR (213m) & Belle (152m)
A–+ –0.47 0.130.14+−
Parameters : α, |T+–|,T–+,T00,P+–,P–+Direct CP violation ?
A+– –0.15 ± 0.09
Scan in α using the bilinears :
BBAABBARAR
A+–
A–+
no direct CPV
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 45
Combination of ππ, ρπ, ρρ : first measurement of α
mirror solution disfavored
for the SM solution we find :
Combining the three analyses (dominated by ρρ and ρπ) :
α +−⎡ ⎤= °⎣ ⎦
9meas. 10100
better precision than CKM fit :
[ ]α = ± °CKM 98 16
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 46
digression : “Color-Suppressed” Amplitudes
Famous modes :0 0 0
0 0 0
0 0 0
BBB
π π
ρ π
ρ ρ
→
→
→
important non-factorizable contributions when large penguins !
[ Suppression ≈ verified in B(B0 → D0π0)/B(B0 → D–π+) = (1/10.4)exp ≈ (1/Nc)2 ]
The color of the quarks emitted by the virtual W must correspond to the external quark lines to produce color-singlets suppression by ~1/Nc (naïve!)
bd d
W −
ud π −
0B u π +
bd
0B
d
ud
0πu
0π
W −
Example : b uud→
0.130.10[ ]| / | 0.10P T ρρ
+− +− +−= [ ]| / | 0.37 0.17P T ππ
+− +− = ± [ ]7.52.1| / | 5.0KP T π
+− +− +−=
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 47
Measurement of the angle Measurement of the angle γγ—— the most difficult taskthe most difficult task ——
Interference of b → c and (suppressed) b → u amplitudes
γ
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 48
The Measurement of γ : Methods
bu u
W −
us
( )K ∗ −
B−
Tree: dominant
c ( )0D ∗
Tree: color-suppressed3cb usV V
λ
∗∝
∝ 3 2 2
ub csV V
λ ρ η
∗∝
∝ +
bu
u
W −
cu ( )0D ∗B−
s ( )K ∗ −
relative CKM phase : γ
No Penguins ☺No Penguins ☺
,b cus ucs→
Measurement of γ through direct CP violation in B decays to charm
Several variants :
D0 decays into CP eigenstate (interference between amplitudes) « GLW »
D0 decays to K –π + (favored) and K +π – (suppressed) « ADS »
D0 decays to KSπ +π – (interference in Dalitz plot) « GGSZ »
Gronau-London, PL B253, 483 (1991); Gronau-Wyler, PL B265, 172 (1991)
Atwood-Dunietz-Soni, PRL 78, 3257 (1997)
Giri-Grossman-Soffer-Zupan, PRD 68, 054018 (2003)
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 49
The “GLW“ and “ADS“ Analyses
GLW : measure branching fraction of B– → D0(CP)K–
4 observables sensitive to γ :
D0CP± reconstructed in ±CP (for ex., D0
CP+→K–K+, D0CP–→KSπ 0) b → c and b → u interfere
0 0 2
0 0
( ) ( ) 1 2 cos cos
( ) ( ) 2 sin sin /CP CP CP B B B
CP CP CP B B CP
R B D K B D K r r
A B D K B D K r R
δ
δ
γ
γ
− − + +± ± ±
− − + +± ± ± ±
∝ Γ → + Γ → ∝ + ±
∝ Γ → −Γ → ∝ ±
( ) / ( )Br A b ucs A b cus≡ → →
strong phase in decay of B
~ 0.1 - 0.3 ??
( )( )
2 2ADS
ADS ADS
(...) 2 cos cos
(...) 2 sin sin /D B B D B D
B D B D
R r r r r
A r r R
γ δ δ
γ δ δ
≡ = + + +
≡ = +strong phase
in decay of D
ADS : disfavor favored amplitude and favor disfavored amplitude
0( )B D K Kπ− + − −→ → 0( )B D K Kπ− + − −→ →
( ) / ( )Dr A c dus A b sud≡ → →
2×Cabibbo-suppressed
= 0.060 ± 0.003
Problem of GLW : requires interference of amplitudes with very different sizes
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 50
“ADS+GLW” : Constraint on γ
BABAR and Belle have measured the observables for GLW et ADS in the modes B– → D0K–, D*0K–, D0K*–
BABAR, hep-ex/0408082, hep-ex/0408060hep-ex/0408069, hep-ex/0408028
Belle, Belle-CONF-0443, hep-ex/0307074hep-ex/0408129
No significant measurement of suppressed amplitude yet ⇒ limit : rB(*) 0.2
γ +−⎡ ⎤= °⎣ ⎦
20meas 3451
γ +−⎡ ⎤= °⎣ ⎦
8CKM 758
for the SM solution :
not yet competitive with CKM fit (indirect determination of γ)
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 51
GGSZ : B– → D0(→ KSπ +π – )K– : interference between amplitudes in Dalitz plot
( ) ( ) ( )
( ) ( ) ( )
2 2 0
02 2
, e
, e
iB
iB
A m m A B D K f r f
A m m A B D K f r f
δ γ
δ γ
−− −− − + −+ +−
++ ++ − + +− −+
⎡ ⎤= → +⎣ ⎦
⎡ ⎤= → +⎣ ⎦
Sum of amplitudes contributing toD0→ KSπ +π –
( )2 2
0
,
( )S
f f m m
m m K π
+− + −
±±
≡
≡
Decay amplitudes :
CP
2
2A− = ( ) iBr e δ γ−+ ×
2m+
2m−2m−
2m+
0D 0D
Simultaneous measurement of rB , δ and γ
K π∗− +
The “GGSZ” Dalitz Analysis
BABAR, hep-ex/0408088
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 52
“GGSZ” : Constraint on γ
Amplitudes of Dalitz plot measured in control sample : D0→ KSπ +π –
large number of resonances contribute : K*(892), ρ (770), ω (782), f0(980,1370), K0*(1430), ...
0B D K− −→
0B D K− ∗ −→
B+ B−
B+ B−
BABAR 211m 0.18 , 0.24B Br r ∗< <stat syst model88 44 19 10γ ⎡ ⎤= ± ± ± °⎣ ⎦1415 stat syst model68 13 11γ +−⎡ ⎤= ± ± °⎣ ⎦ 0.21 0.09 , 0.39B Br r ∗= ± <
(90% CL)
Belle 274m (FPCP’04)
Future : reduce model-dependence by exploiting CP-tagged results from CLEO-c running at theψ(3770) → DD to measure arg[f+–] and arg[f–+] ?
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 53
digression : Measurement of sin(2β + γ)
bd d
W −
ud π −
0B
Tree: dominant
c D+
Tree: doubly CKM-suppressed 2cb udV V
λ
∗∝
∝ 4ub cdV V
λ
∗∝
∝
bd d
W −
cd D−
0B u π +
relative weak phase :
Exploit interference
BABAR and Belle have performed this analysis for D π, D*π and Dρ, using fully and partially reconstructed B decays.
Similarly:
golden mode to measure γ at LHCb/BTeV
0 ( )B D π∗ − +→ 0 0 ( )B B D π∗ − +→ →
2β γ+
Time-dependent CP analysis similar to : B0 → ρ +π –
0 0( )s s sB B D K− +→
,b cud ucd→
γ dependence of the order of O(10–4) !
Huge statistics, but small CP asymmetry
Unknowns : rB0, γ and δ ⇒ needs external input
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 54
constraint on |sin(2β+γ)| constraint of sin(2β+γ) in ρ-η plane
Using SU(3) symmetry to estimate rB0(*) (assumed theoretical errors : 30%)
digression : Results for sin(2β + γ) BBAABBAR AR & Belle& Belle
BABAR, hep-ex/0408038, hep-ex/0408059 Belle, hep-ex/0408106, PRL 93 (2004) 031802; Erratum-ibid. 93 (2004) 059901
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 55
Summary :Summary : CPCP Violation in 2004Violation in 2004
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 56
First measurement of CPV : εK
Precise measurement of sin2β
First measurement of α
γ — the biggest challenge
Summary : CKM Metrology
Measurements of the CKM phase :
Significant progress on |Vcb,ub|
...but this is only the half time :4 × stat. (~ 2 ab–1) expected in 2009
First measurement of cos2β
β >cos(2 ) 0
β <cos(2 ) 0
Beyond CKM metrology :
Direct CP violation in B system
Quid the s-penguins ?
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 57
a p p e n d i x (i)t h e f u t u r e o f f l a v o r p h y s i c s
a p p e n d i x (i)t h e f u t u r e o f f l a v o r p h y s i c s
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 58
The Future Program for The Future Program for Flavor Physics and Flavor Physics and CPCP ViolationViolation
ATLASATLASATLAS CM
S
CCMM
SS
BTEVNA48
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 59
2000 2002 2004 2006 2008 2010
BABAR 100 / fb 500 / fb 1.x / ab ?
B and D Factories
NA48
K0PI0 (BNL)
Kaons (high intensity)
CDF & D0
ATLAS & CMS
Tevatron Run 2
LHC
SUNS at PSI
NA48/1 NA48/2
LHCb
BTeV ?
3-7 1035 ?
CLEO 10 / fb
E787 / E949
NA48/3
Belle 100 / fb 500 / fb 1.x / ab ? 2 1035 ?
CLEO-cscan
ILL, PNPIElectric dipole moment of neutron
@ J-PARC ?E391a (KEK) [~ 4×10–10]
ILL
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 60
a p p e n d i x (ii)t h e C K M e l e m e n t s |Vub| a n d |Vcb|
a p p e n d i x (ii)t h e C K M e l e m e n t s |Vub| a n d |Vcb|
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 61
( )
3 2 2 2et
circle in , planeub cbV A V Aλ ρ η λ
ρ η
= + =
⇒
The Elements |The Elements |VVubub| and || and |VVcbcb||—— semileptonicsemileptonic B B decays decays ——
/ub cbV V
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 62
The CKM Matrix elements : |Vub| and |Vcb|
The theoretical tools are HQET and HQE (OPE).
|Vub| (→ ρ2 +η2) is crucial for the SM prediction of sin(2β )
|Vcb| (→ A) is important in the kaon system (εK, BR(K→πνν ), …)
d s b
u
c
t ( taille ∝ |Vij | )
b → u
b → c
exclusive inclusive
B → ρ ℓν
B → D* ℓν
B → Xu ℓν
B → Xc ℓν
For |Vcb| and |Vub| exist exclusive and inclusive semileptonic methods
… concentration on the inclusive modes in the following
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 63
|Vub| (and |Vcb|) : Principle of Inclusive Measurements
( )QCD2
[ , ] ~ quark model (PS) b
n
u c b n mn
d V Cd
ΛΓ ⎛ ⎞× +⎜ ⎟⎝ ⎠
∑
free quark decay non-perturbativecorrections
☺ : relation between and |Vub| known to ~ 5%
: background from b → c dominant :
( )u
uX
B X νΓ →∑ l
( ) / ( ) ~ 100c uB X B Xν νΓ → Γ →l l
Hadronic mass spectrum in b u decays
kinematic limit of b → c
parton modelincluding the Fermimotion (model)
only b→u
1/ΛQCD
Compton wavelength
b
mb–1
Fermimotion
needs severe cuts to eliminate charm background
Fermi motion can be determined from γspectrum in b → s γ
Belle, hep-ex/0403004
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 64
|Vub| : Results
Electron momentum (GeV/c)
Num
ber o
f ele
ctro
ns
b ueν→b ceν→
( ) 3stat+sys SF HQE3.94 0.25 0.37 0.19 10ubV −= ± ± ± ×
… the electron endpoint … the invariant mass q2(e,ν)
b ueν→b ceν→
( ) +0.59 3stat syst 0.29 SF HQE4.57 0.47 0.22 10ubV −
+ −= ± ± ×
BABAR, hep-ex/0408045, hep-ex/0408075
b → ceν background rejection with cut on …
« electron endpoint »
« ν reco »
mD
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 65
|Vcb| - Moments Analysis
Hadronic mass moments
Lepton energy momentsRed line : HQE fitYellow band : uncertainty
( ) 3stat HQE theo41.1 0.4 0.4 0.6 10cbV −= ± ± ± ×
BABAR, PRL93, 11803, (2004)
2% precision !
Seminar at Lausanne - Feb 14, 2005 A. Höcker – Mid-Term at the B Factories : the New Picture of CP Violation 66
Compilation of |Vub| and |Vcb| Results
Disagreement between exclusive and inclusive |Vub| determinations ?