CP violation and Heavy Flavours

1
CP violation and Heavy Flavours
Marie-Hélène Schune
Introduction

• A taste of K and D results
• K???? and KL??0ll decays
• Ks??0 ?0 ?0 and K????????
• D??? (fD)
• Semileptonic charm decays

• Vtd, Vts
• B mixing
• rare B decays

• Vcb, Vub
• Semileptonic decays
• B???

• CP violation in B decays
• B?charmonium (? / ?1)
• B ?D()K() (? / ?3 , ? / ?1 )
• Charmless B decays (? / ?2 , ? / ?1 )

Apologies to those whose work I dont have time
to mention.
Overall status
2
Framework the CKM matrix
Heavy flavours !
?sin(?c) 0.2256 ?0.0014
1-?2 ? A
?3(?-i?) -? 1-
?2/2 A ?2 A?3(1- ?-i?) -A ?2
1
VCKM
CP violation
O(?4)
?
(?,?)
The unitarity triangle
?/?2
(1,0)
? /?1
? /?3
?
(0,0)
3
Constraints in the (?,?) plane
4
Some of the experiments
ee- ??(4s)
ee- ? ?(3770)
BELLE
BABAR
CDF
D0
pp ?s1.96 TeV
5
The B experiments main characteristics
Tevatron RunII integrated luminosity
After a long shut down BABAR is back in operation
6
Experimental techniques at B factories
B-Flavour tagging
Exclusive B meson reconstruction
Dt1.6 ps ? Dz ?200, 250 mm
Exploit kinematic constraints from beam energies
Beam Energy-substituted mass
Energy difference
Event shape
?(4S) rest frame
s(DE) mode dependent
s(mES) ? 3 MeV
7
A taste of K and D results

• Kaon physics
• K???? and KL??0ll decays
• Ks??0 ?0 ?0 and K????????
• Charm physics
• fD
• Semi-leptonic charm decays

PDG02
New measurements (K??e? BF, form factors, )
Theoretical developments
The  unitarity problem  of the first line seems
to be solved
8
K???? and KL??0ll
NP effects can be different
Dominated by s(BF(KL??0ll )) NA48/KTeV.
Theoretical precision should be ultimately 10
9
KS??0?0?0 and K????????
KLOE 450 pb-1 0102 data

• Ks??0 ?0 ?0 CP violating decay (SM 1.9 10-9)
• K???????? direct CP violation
• Comparison of the Dalitz plot shape between K
  and K- (no amplitude fit)
• SM Ag10-6 to 8 10-5

Nbkg(MC) 3 ? 1
c22p
Signal box
c23p
NA48/2 Ag (0.53.8)x10-4
10
Measuring fD CLEO-c

• Pseudo scalar decay

Vcd
? wave function overlap
DD production(?(3770)). One D is fully
reconstructed ? kinematical constraints for the D
?l?. Use of the missing mass (MM2)
EDEBeam
One D? mn candidate
11
CLEO-c 281 pb-1
50 events NBkgd2.92?0.50
Recent unquenched lattice result
Latest unquenched calculations agree well! In the
future, derive prediction for fB, needed for to
obtain Vtd from Dmd
12
Semi-leptonic D decays
CLEO-c 56pb-1
D?Ke?
D?Ke?
D?p0e?
639
D?r0e?
246
D?we?
83
First Observation
Validation of LQCD (D?K l? )
Vcd
Extraction of D form factors
D BF measurements
B form factors (D? ?/?l?)
Vub
13
Vtd and Vts
14
B0-B0 Oscillations Dmd
HFAG
BELLE 152 106 BB . Full B reconstruction
Dmd a high precision measurement (1)
dominated by B factories results
Dmd 0.509?0.005 ps-1

• Weak constraint on the UT triangle

• Use

SU(3) flavour breaking smaller theoretical
uncertainties
1
15
Dms
Expectation from fits to the Unitarity Triangle
Due to the size of the CKM elements Dms gtgt Dmd
Dms 22.2 ?3.1 ps-1
HFAG
First limit was set in 1993 at Dmsgt1.8 ps-1 at
95CL !
Dms gt 14.4 ps-1 at 95CL
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Dms at the Tevatron
Bs?Ds?? with Ds ? ?? and KK
D0 610 pb-1
Tagging performances
Time resolution
Signal reconstruction
CDF (now) 0.025
CDF
Curves obtained using measured sA
Current analysis
Tagging0.01 Vertex resolution 10
95 CL exclusion
Tagging0.03 Vertex resolution 20
1.7 fb-1
4 fb-1
CDF(/D0) should be able to push the limit up to
20 ps-1
Semileptonic Bs decays better limits on Dms at
present. Hadronic Bs decays not enough
sensitivity, but will eventually measure Dms
with more data!
17
Radiative B decays

• New Physics
• BF of b?sg and b?dg
• Standard Model
• Eg spectrum in b? sg
• BF(b?sg)/BF(b?dg) ? Vtd2/Vtd2

b?s?
Inclusive photon energy spectrum sensitive to
b-quark motion inside B meson ? reduces the
systematic uncertainty in the Vcb and Vub
extractions
Semi-inclusive analysis (55 of the modes
reconstructed)
BELLE 152 106 BB
Fully inclusive analysis
BABAR 88 106 BB
BABAR 88 106 BB
K peak visible due to the good resolution
18
B??/? ?
SU(3) breaking correction weak annihilation
diagram for BR(B ? ?/w ?)
First observation 5.5s
19
Semileptonic decays Vub and Vcb
Weak decay of a free quark
G0?
At the hadron level
free quark decay
Perturbative non-perturbative corrections
Exclusive decays depend on QCD form factors
from eg LQCD, quark models... Inclusive decays
use Heavy Quark symmetry OPE measure OPE
parameters from data (spectra and moments of b?sg
and b ? cln distributions) Complication for
charmless decays ? need to apply kinematic
cuts to suppress b ? cln background ?
measurements of partial branching fractions in
restricted phase space regions ? theoretical
uncertainties more difficult to evaluate
Exclusive and inclusive semileptonic approaches
different theoretical uncertainties
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Inclusive Vub
Vub(x10-3)
ProsCons
S/B
method
Untagged
4.23 0.27exp 0.31theo
0.05?0.2

• High statistics
• Bkg subtraction

Electron spectrum endpoint Eegt1.9 (2.0) GeV
4.82 0.45exp 0.31theo
Ee vs q2 neutrino reconstruction Eegt2.0GeV and
shlt3.5 GeV2/c4
Untagged
signal region

• High statistics
• Lower syst. on
• shape functions
• Bkg subtraction

0.5
normalize the background
4.06 0.27exp 0.36theo
in the B rest frame
Breco Tags
2
4.76 0.34exp 0.32theo
mX vs q2 analysis mXlt1.7 GeV/c2 and q2 gt8.0
GeV2/c4

• Low background
• Very small syst.
• on SF param.
• Small statistics

4.08 0.27exp 0.25theo
signal
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Vub exclusive B??l? B??l?
BABAR 83 106 BB
Fit of the signal yield using the B mass and DE
in bins of q2.

• Measure the form factor q2 dependance.
• Compare with theoretical calculations

8 precision
Can improve the S/B by tagging one B
BELLE 253 fb-1

• Ball01
• ISGW2
• ? UKQCD

p0ln
p-ln
d?/dq2 /?tot x 104
d?/dq2 /?tot x 104
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Vcb and Vub from semileptonic decays summary
Vub inclusive (HFAG)
Vub exclusive (HFAG using FNAL full q2 range)
8 precision
BF precision8 but Vub precision 20 ?
theory dominated
Vcb inclusive (Buchmüller/Flächer)
Vcb (41.58?0.45?0.58GSL)10-3
2 precision
Vcb (10-3)
Good agreement
mb(GeV)
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B?????
Limit on m(H?) in a 2 Higgs doublet model

• In the SM it measures fB Vub
• Direct measurement of fB when using Vub from
  SL decays
• To be compared to LQDC predictions
• Test of NP
• E.g. charged Higgs could enhance BF
• Experimental technique
• One B fully reconstructed (hadronic or
  semileptonic)
• Search for ?? in the rest of the event (2n)

Getting close!
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CP violation in B decays
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Three Types of CP Violation
Following Yossi Nirs graphical display
A1
1
1. CP violation in the decay
B0
A2
3
1

• Two amplitudes with different weak and strong
  phases
• Exp can be seen both in B0 and B? decays
• E.g. b?c and b?u ?

2
2. CP violation in the mixing
same final state f
very small but very important !

• Exp N(B0B0 ? llX) ? N(B0B0 ? l-l-X)
• The mass eigenstates are not CP eigenstates

3. CP violation due to the interference between
mixing and decay
26
B ? charmonium
B0 ? f
B0 ? B0 ? f
B0 tag
C0 Ssin(2b)
New BELLE result for J/?K0 (386 106 BB)
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Determination of b/?1
HFAG Average 0.685 0.032
5 precision
Coherent description of CPV within the SM SM is
the dominant source of CPV
Constraint from sides only 0.720?0.024
(CKMFitter)
HFAG LP2005
Preferred solution Use of the B0 ? J/?K(?Ks?0)
(VV decay) information on cos(2b) (after strong
phase ambiguity resolution) BABAR PRD
71, 032005 (2005) cos(2b)gt0 at 86CL
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B? D()K() measurement of ? (?3)
rB CKM elements color suppression 0.1-0.2
A(B-?D0 K-) AB
d CP conserving strong phase between b?c and
b?u
if same final state CP violation in the decay

• D0? CP final state (Gronau London Wyler)
• D0 ? CS mode (Kp-) (b?c)x(c?d) vs
  (b?u)x(c?s) (Atwood Dunietz Soni)
• Mixture of the two . D0 ?Ks?? (Giri Grossman
  Soffer Zupan)

• Main points
• Tree diagrams theoretically clean measurement
  of g
• rB values ?
• Low stat (GLW, ADS) effective BF 10-7
• Dalitz model for the D0 3 body decay

29
B??D0CPK()? (GLW) and B??D0(CS)K()? (ADS)
Use B B- asymetries and ratios of BF which are
functions of rB, d and g
GLW case
New results in ADS analyses
BABAR 232 106 BB
BELLE 386 106 BB
rBlt0.18 at 90CL
DE
small rB ? no g sensitivity
Consistent with the B charmless peaking background
mES
30
B??D()0K()? Dalitz method (GGSZ)
CP
D0?Ks??
Different modes all measuring g
f(m2,m2-) obtained using a tagged D0 sample
BABAR 227 106 BB
D0K
(D0?)K
(D0g)K
() as pointed out by A. Bondar and T. Gershon
hep-ph/0409281
31
B??D()0K()? fit
1. Extract f- from a tagged D0 sample (D?D0?)
2. Fit A(B)2 in each point of the Dalitz plot
Due to the low statistics and the physical bound
(rBgt0) , a fit of g and rB exhibits highly non
gaussian effects. Use the cartesian coordinates
BELLE 275 106 BB
32
B??D()0K()? results
?(?) depends strongly on the rB value

• Due to the Dalitz model parametrization
  (s-wave)
• Improvements
• using the K matrix formalism for the
  controversial pp s-wave description 3 (BABAR)
• directly extract the D strong phase variations
  from data cleo-c

33
Overall information on rB and ?3/? from GLW, ADS,
Dalitz
rDK 0.081 0.029 0.021,0.138 _at_95 CL
UTFit
rDK 0.088 0.042 0.010,0.170 _at_95 CL
rDK 0.15 0.09 0.01,0.31 _at_95 CL

• rB is small
• g is not easy to measure.

34
B0?D()0 ?0/?/?
A. Bondar, T. Gershon and P. Krokovny,
hep-ph/0503174
Time dependent analysis of B0?D0?0 with the
Dalitz of D0 ?Ks?? ? direct measurement of b
if D0CP sin(2b)
Time dependent measurement of the D0 Dalitz plot
density
Similar to the B??D()0K()? Dalitz method (GGSZ)

BELLE 386 106 BB
D0 ?
D0?0 D0 ?
D0?0
D0 ?
mES
Ns157?24
Ns67?10
Ns58?13
Ns27?11
Confirms B0 ? J/?K(?Ks?0) analysis
35
Charmless B Decays
b?uud transitions
a measurement Direct CP violation
Search for new physics
36
CP violation in B0? p p / ??-
Access to a from the interference of a b?u decay
(g) with and without B0B0 mixing (b).
Assuming pure tree diagram
?VubVud ?Al3
C0 Ssin(2a)
But penguins may be of the same order of
magnitude as trees
d relative strong phase between T and P
To extract a from aeff use SU(2)-isospin
37
CP violation in B0? p p
Cpp
Agreement between BABAR and BELLE has improved
Spp
Isospin triangles
B0? p0p0
In order to bound a-aeff needs p?p0 and p0p0
...
p0p0 is too small for a isospin analysis and too
large to set a useful a-aeff limit
38
CP violation in B0? ??-
BABAR 227 106 BB
full PDF
backgrounds

• Larger branching fraction than pp
• Small BF(B0?r0r0) (lt 1.1 10-6)
• Low penguin contamination ? good limit on a-aeff
• VV final state ? 3 polarization amplitudes
• In principle dilution due to mixed CP
• In practice dominated by longitudinal
  polarization
• ? pure CP-even state

highest purity tagged events
Likelihood signal enhanced
cos( r helicity angle)
a-aeff lt 11
a 9613
39
Overall constraint on a
Additional constraints on a from time dependent
CP violation analysis of B???

• pp determination very weak

rr best individual measurement
Mirror solution are disfavored by rp
40
Direct CP violation
For two-body decays only seen clearly (gt 4s) in
one single channel
B0?K?-
For three-body decays first sign of direct CPV
Full Dalitz Kpp fit
Fit projections in the r region
BELLE (386 x 106 BB)
Direct CP violation at 3.9 s
BABAR 227 106 BB
41
CP violation in b?sss transitions
Loop sensitive to new physics

• A large class of channels
• B0?? Ks, B0? ? KS
• B0? KK- Ks , B0? Ks Ks Ks , B0? f0 Ks
• Experimental challenges
• BF much smaller than J/? Ks, higher continuum
  background

BELLE 386 106 BB
BABAR 232 106 BB
B0 ??Ks
B0? ? KL
B0 tags
Bkgd substracted dist.
Signal enhanced plots (L ratio)
background
precise tagging cat.
Time dependent fit performed together with ? Ks
SM
Dt(ps)
Dt(ps)
42
CPV in b?sss transitions and sin(2b)

• Since winter 2005
• improved accuracy
• better agreement between BABAR and BELLE
• all systematically below sin(2b)
• QCD corrections sin2b(penguin)gtsin2b(tree)

All modes (except ?Ks and p0 p0 Ks ) are less
than 1.5 s away from sin(2b) from J/? Ks
recent QCD factorization estimates
Beneke, hep-ph/0505075 Cheng,Chua,Soni,
hep-ph/0506268
sin2b(penguin)-sin2b(tree)
43
Overall status and summary
44
General overall agreement !
? 0.216 0.036 ? 0.342 0.022
Besides slightly different theoretical inputs and
different statistical treatments Coherent
picture of CP violation in the SM framework The
CKM mechanism works well NP should appear as
correction to this framework
45
Tree processes NP free
Testing for NP
? CKM parameters determination. NP should satisfy
these constraints
Precise determinations of Vub/Vcb and g are
crucial to fix Unitarity Triangle parameters
valid in any NP extensions
NP in the mixing 3 new parameters
See (eg) G. Barenboim, G. Eyal and Y. Nir, Phys.
Rev. Lett. 83, 4486 (1999) and CKMFitter group in
Eur.Phys.J.C411-131,2005
Disfavored by Asl
NP
SM
NP in the Bd sector
?d 0 ? NP phase SM phase
46
Summary

• fD is measured by CLEO-c
  and is in agreement with LQCD
• B??/? ? seen by BELLE for the first time
• B??? first direct access to fB 0.178 0.062
  GeV
• Dms still out of reach will need Bs? Ds?
  hopefully will be measured at the Tevatron?
• Vub entering the precision era (discrimination
  between theoretical models)
• CP violation
• sin(2b) b ?(cc)s precision 5 b ?(ss)s NP
  physics tests need more precision
• g difficult to measure due to the small rB
  value
• a well measured by B??? decay
• NP search
• CPV in the mixing
• Model independant parametrization ?d 0
• Bs window still to be looked at

47
Outlook

• More data !
• B factories 2-4 ? the present statistics at
  the end of 2008
• Tevatron 2-4 ? the present statistics before
  LHC startup
• Cleo-c 10 ? the present statistics at
  ?(3770))
• LHCb
• Dms

5? observation up to Dms68 ps-1 1 yr
st 40 fs
LHCb calorimeter at CERN

• B?s?J/?f (h) sensitive to the weak phase of Vts
  SM fs -2?2? -0.04 . One year s(sinfs) 0.06

Sensitivity to NP in the Bs sector
48
Much more experimental details can be found in
the talks by
G. Della Ricca
S. Behari
F. Blekman
S. Blyth
Y. Chao
R. Chistov
J. Ding-felder
J. Dragic
D. Dujmic
T. Ferbel
Y. Gao
D. Hutch-croft
C. Jessop
T. Gershon
P. Grenier
T. Hokuue
W. Huls-bergen
A. Ishikawa
G. Lamana
M. Moulson
K. Ikado
J. Kasper
L-M Mir
N. Leonardo
F. Ronga
J. Stark
A. Limosani
D. Moha-patra
C. Potter
I. Shipsey
V. Pavlunin
C. Sch-wanda
A. Oyan-guren
K. Trabelsi
A. Somov
V. Tisse-rand
J. Yi
O. Tajima
K. Uchida
M. Wang
A. Sznajder
C. Voena
M. Wache
C. Yeche
Many thanks to
G. Borissov
D. Dujmic
A. Höcker
G. Gros-didier
T. Browder
C. Hearty
C. Bozzi
D. Asner
R. Van Kooten
S. Giagu
M. Herndon
B. Kowa-lewski
F. Le Diberder
M. Pierini
O. Sch-neider
A. Stocchi
H. Lacker
G. Sciolla
V. Luth
V. Lubicz
J. Qian
Y. Sakai
for their help in preparing this talk
CKM Fitter group
HFAG group
UTFit group
C. Yeche