BaBar: review of current results
Riccardo Faccini
University “La Sapienza” and INFN Rome
SLAC DOE review, May 5th 2006
Mission of the talk



Hassan has just given you an outlook of the
physics and the program
I will show recent developments in three
creativity
dimensions!
accuracy
Twofold goals
productivity

Overconstrain the unitarity triangle



High luminosity allows accurate measurements
Creative techniques squeeze out every bit of information
Search for indications of physics beyond the
standard model


Comparison of accurate measurements with SM predictions
Search for new states in “any” final state
Publication Luminosity
creativity
accuracy
productivity
Journals
BABAR
Belle
Total submitted
214
172
Since Sep ’05
42
23
+ 16 more preliminary results for winter confs (58 total!)
+ 151 abstracts submitted at ICHEP [23+ parallel talks]
Breakdown by topic
All Areas
Breadth of results well
beyond the original plans
creativity
accuracy
productivity
by Sep 05
# pubs
By “Grand” areas
by Sep 05
Angles of the unitarity
triangle
a
g
b
CP violation in mixing and decay
t 0
B
mixing
B
Consider B decays to a
mode f
0
t
Af
CP
Af
0
f is not necessarily
a CP eigenstate
f
t
Sf 

t
e 
P ( t ) 
[1  C f cos ( md t )  S f sin ( md t )]
4
 2 Im  f
1 | f |
2
Cf 
1 | f |2
1 | f |2
A( B  f )Vtd*Vtb A i 2 b
 f
 e
*
A( B  f )VtdVtb A
Mixing phase
Penguins and new physics
„golden“
Tree:
b
c J /
c

cb
V
W

Vcs
d
b
K0
d
Penguin
„bsg“:
s
W + New
Physics?
VtbVts
h’
„Nasty“
Tree
u u
d

ub
V
W
In presence of New Physics
SJ/YKs≠ Sbsg
s f,h’
s
s K0
d
d
b
In the standard model these two
amplitudes have the same
phases  SJ/YKs=Sbsg

Vus
s
K0
d
Because of these tree diagrams with
different weak phase [Arg(Vub)=g ]
SJ/YKs≠ Sbsg also in the SM
Critical tools for bsg

1) Ideas on new modes


Precise SM prediction: fKs,KsKsKs ©2004
Uncertain Tree Pollution: f0Ks,h’Ks,K+K-Ks©2003
Large Tree Pollution: wKs,Ksp0©2004, rKs©2006
A very exciting period
• Lots of theoretical studies
• new ideas pouring in continuously ©
•Hints of deviations from the standard model
2) Maximum likelihood analysis
to maximize sensitivity in
presence of high backgrounds
Note: many Dalitz plot
analyses in high background!!!
-
p+
-
p
BKsp0
p0
KS
3) Exploit the resolution of the
SVT to measure B vertices even in
absence of prompt tracks
7mm
B0
Beam spot
beam
200mm
Deviations from SM?
Measured S values
Goal: estimate if the measured S
parameters show a deviation
from SM expectations.
Standard Model expectations
(deviation from bcss)
[Beneke, hep-ph/0505075
2 colors  2 ways to
estimate theory errors]
[Cheng,Chua,Soni
, hep-ph/0506268]
Weighted average
(with th. Errors)
~3s from SM
Name of the game:
• add more modes
• reduce theoretical errors
sin2b
Details from D. Dujmic tomorrow
The latest addition: B → rKS
(or c+!)


Significant deviation from
“golden” sin2b
(S as low as 0.2)
High sensitivity to new physics
Buchalla, Hiller, Nir, and Raz
(hep-ph/0503151)
XccKs
B 0  XKS0
Theo. Models
Large tree pollution:
Experimentally:


High backgrounds
Understand ppKs Dalitz
structure
S
rKs results
B0 tags
B0 tags
Asymmetry
BaBar:
sin2b=0.17±0.52±0.26
C=0.64±0.41±0.25
•A large source of error
comes from the possible
CP-even under the rho
(including interference
effects)
•still statistically limited,
but hinting in the
direction of
expectations
Deviation from SJ/YKs in Bh’Ks
h’
„Nasty“
Tree
h’
u u
b
d

ub
V
W

Vus
u u
s
b
K0
d
Diagram to be understood
(example)
d

ub
V
W

Vus
d
h,p 0
d
Measured diagram
(example)
Measure BF of h’p0,hp0,h’h to constain these contributions
h’K0 SM pollution: h’p0,hp0,h’h
All plots
for h’p0
•
•
Expectations for the BRs
are ~0.2-2 x 10-6
Reduction by ~20% of
theory uncertainty in
sin2b(h’KS)
Gronau, Rosner, Zupan PL B596, 107 (2004)
BaBar:
BR(h’p0)<2.1x10-6
BR(hp0)<1.3x10-6
BR(h’h)<1.7x10-6
hep-ex/0603013
Measurements of g
~ eib
B0
Critical parameter
A( B0  D(*)p  )
r
~ 0.02
A( B0  D(*)p  )
Acp~ r sin(2bg)sin(mt)
B0
D0K+
Critical parameter
rb 
A( B   D 0 K  )
A( B   D 0 K  )
~ 0 .1
A(B0  D+p-)
~ |Vub| eig
Name of the game:
find the process with
the largest value of
r*sqrt(Nsig)
D+p-
Sensitive to sing
B+
~ rb
eig
D0K+
[f]K+
0
DK
Dalitz analysis: the idea
D0K+
Critical parameter
rb 
A( B   D 0 K  )


A( B  D K )
0
~ 0 .1
Sensitive to sing
B+
~ rb eig
f= CP eigenstate (GLW)
 measure g
f= DCS (ADS)
 measure rb
f=3-body (Dalitz)
 measure both
[f]K+
D0K+
D0Kspp: Sensitivity to g
f=Ksr
f=DCS K*p
D0 Kspp : results (BaBar + Belle)
γ = 65 ± 20 ([27,107] @ 95% Prob.)
B0 D(*)0K(*)0 decay modes
Vcb transition
Theory paper:
Phys.Lett.B 253,483(1991)
PRL 78,3257 (1997)
PRD 61,116013 (2001)
Vub transition
λc
r
D
(* )0
K
(* )0

V
~0.4
 V
1
ub
c
cb
•Vub and Vcb mediated amplitudes both color suppressed:
LARGE INTERFERENCE
(GOLDEN MODE FOR LHCb)
•Measure ‘r’ in self-tagging final state D0K*0
B0 D(*)0K(*)0 decay modes
hep-ex/0604016
Preliminary
BABAR
Preliminary
•rB value smaller than theo. expectation
•Not useful to measure g value yet!
BABAR
Preliminary
Results on 226 Million BB
BABAR Preliminary
Exploring fundamental symmetries
Still learning from di-lepton events

Both B’s decayed semileptonic and only the
leptons are identified:


huge stat: 1.4M events after selection
Backgrounds/resolutions to be controlled accurately
Without assumptions
on symmetries
Define:
CP symmetry  p=q
CPT symmetry  z=0
T/CP/CPT Violation in
0
B
mixing
q / p  1.0008  0.0027( stat )  0.0019( syst )
Im( z )  0.0139  0.0073( stat )  0.0032( syst )
x Re( z )  0.0071  0.0039( stat )  0.0020( syst )
40% reduction in s(q/p)
80% reduction in s(Im(z))
First Measurement of Re(z)!
hep-ex/0603053
Constraints
on New Physics
from |q/p|
NP ?
SM
after
before
SM
Other papers on these topics

a
hep-ex/0603050 Observation of B0 Meson Decay to a+-(1)(1260) pi-+.
hep-ex/0605024 Search for the decay B0 to a1 rho
hep-ex/0605037 Search for B+ -> phi pi+ and B0 -> phi pi0 Decays

b
hep-ex/0603012 Measurements of the branching fraction and time-dependent CP asymmetries of B0>J/psi pi0 decays
hep-ex/0603040 Measurements of CP-violating asymmetries and branching fractions in B decays to
omega K and omega pi.
hep-ex/0603054 Measurement of branching fractions in radiative B decays to eta K gamma and search
for B decays to eta-prime K gamma.
hep-ex/0605003 Dalitz plot analysis of the decay B+- -> K+-K+-K-+
hep-ex/0605017 B Meson Decays to mega K*, omega rho, omega omega, omega phi, and omega f0.

g
hep-ex/0509036 Measurement of branching fractions and resonance contributions for B0 ---> anti-D0
K+ pi- and search for B0 ---> D0 K+ pi- decays
hep-ex/0512031 Search for the rare decays B0 ---> D(*)+(s) a-0(2)
hep-ex/0512067 Measurements of the branching fractions and CP-asymmetries of B- ---> D0(CP) K
decays
hep-ex/0602049 Measurement of time-dependent CP asymmetries in B0 ---> D(*)+- pi-+ and B0 ---> D+rho-+ decays
hep-ex/0604012 Observation of Decays B0 ---> D_s(*)+ pi- and B0 ---> D_s(*)- K+
hep-ex/0604037 Measurement of Branching Fractions and CP-Violating Charge Asymmetries for B
Meson Decays to D(*)D(*), and Implications for the CKM Angle gamma
Rare B decays
Vub
Vcb
Vtd
Vcb
Vub and semileptonic B decays


Well past the pioneering age: large amounts of bu l n
reconstructed events
We can afford fully reconstructing one of the two Bs in
order to know exactly what is on the recoil
e~0.3% but large purity
and clean event
reconstruction
Details from J. Dingfelder tomorrow
Inclusive |Vub|
Several different approaches,
with different systematics
Vub @ 7.5% !!!
A 2+ s deviation is building up between Vub and the rest of the fit
 hint of new physics ?!?
We need to be sure about theoretical uncertainties in order to make a claim
New: reducing model dependence in Vub
Inclusive Vub:



( B  X u l ) 
Relate charmless SL
rate to b→sg spectrum
Reduced dependence
from shape function
Recoil analysis on 88M
BB
Raw Data
Vub
Vts
2
2
d( B  X sg )
 W ( Eg ) dEg dEg
hep-ex/0601046
LLR : MX < 1.67 GeV:
|Vub| = (4.43 ± 0.38stat ± 0.25syst ± 0.29theo) 10-3
OPE: MX < 2.50 GeV:
|Vub| = (3.84 ± 0.70stat ± 0.30syst ± 0.10theo) 10-3
Subtract b → c
Leibovich, Low, Rothstein hep-ph/0005124,0105066
mX cut
Rare Decays: Radiative Penguins
Can we separate?
Photon penguin (C7)
Vector EW (C9)
Axial-vector EW (C10)
First angular analysis in B -> K(*)ll
B→
(*)
K ll:
rare, or medium rare?
“Find ~50 needles in a haystack of 500 million B’s + 2 billion light quarks” – J. Berryhill
BaBar finds the needles:
B→ Kll
• Rates are well measured
• What can we do with these decays?
Start to investigate angular
distributions and asymmetries!
l-
q*
B
SM
Forward-backward
asymmetry AFB vs. q2
C7 = -C7(SM)
C9C10 = -C9C10(SM)
C7 = -C7(SM), C9C10 = -C9C10(SM)
C10 evolution relative
to C7 and C9
l+
B
cosqK → K* polarization
p
qK
K
New: first angular analysis in BK(*)ll
K* polarization FL
hep-ex/0604007
K* polarization consistent
with Standard Model
Preliminary
SM
C7 = -C7(SM)
Possible to exclude
C7 = -C7(SM) with 1 ab-1
Forward-backward asymmetry AFB vs. q2
SM
q2
Low limit excludes
SM at 98% CL (2.1s)
AFB  0.19 (95% C.L.)
AFB ( SM )  0.03
SM
wrong-sign C9C10
excluded at >3s
C9C10 = -C9C10(SM)
Preliminary
More papers on the topic
 Semileptonic
hep-ex/0509040 Measurement of the Inclusive Electron
Spectrum in Charmless Semileptonic B Decays Near the
Kinematic Endpoint and Determination of |Vub|
hep-ex/0602023 Measurements of the B to D* Form Factors
Using the Decay B0 --> D* e nu_e
 Rare decays
hep-ex/0510051Search for the W-exchange decays B0 -->
Ds(*)- Ds(*)+
hep-ex/0512028 Search for rare quark-annihilation decays, B
 Ds(*) Phi
hep-ex/0604009 Study of the decay B0bar -> D*+ omega pihep-ex/0604017 Measurement of the B- -> D0 K*- branching
fraction
Non-B physics
BaBar as a Charm/ factory and more:
 New Charm and Charmonium states
 Charm decays properties (e.g. mixing)
  decay properties and search for lepton flavour violation
 Quarkonium properties
 measurements of R=shad/smm
 studies of hadronic interactions
Hints of new spectroscopy
X(3872)
Y(3940)
B decays
Z(3930)
gg
B decays
BELLE
2003
2004
BaBar
2005
DsJ(2458)
DsJ(2317)
continuum
Y(4260)
ISR
Different expertise/ trigger in expts:
Charm vs Charmonium
Different productions
Having two experiments
is vital
in this game
diffent
JPC
Investigating Y(4260) Confirmed by CLEO-C Scan:
Observed in ISR by BaBar:
(2S)
and CLEO-C!
…and by CLEO-III !
what is it?
Investigating Y(4260) in other final states
Not found in Y(4260) → ppf:
M(K+K-)
Y(4260) ≠ glueball?
eeY  B(Y (4260)  p p f )
 0.4 eV @ 90% CL
…or in Y(4260) → pp
Y(4260)
B(Y (4260)  pp )
 0.13 @ 90% CL
B(Y (4260)  p p  J  )
Y(4260) ≠ tetraquark?
Not found in Y → DD either:
B(Y (4260)  DD )
B(Y (4260)  p p  J  )
 7.6 @ 95% CL
Y(4260) ≠ molecule?
hep-ex/0509040
New Studies of DsJ(2317) and DsJ(2460)
A broad frontal assault to gain further insight
into the nature of these new (2003) states
hep-ex/0604030
If JP=0+ and JP=1+
Look in final states:
Dsp 0 , Dsg , Ds* (2112) p 0 , DsJ* (2317) g , Dsp 0p 0 ,
Ds* (2112) g , Dsgg , Dsp  , Dsp p 
…but no new decay modes observed
Updated branching ratios, masses, widths:
No surprises…
More Studies of DsJ(2317) and DsJ(2460)
First measurement of absolute BFs
Look for resonance
structure in B recoil
p
D*
e-
hep-ex/0605036
Bsignal
Breco
e+
D*
X
Combine with previous measurements of
partial rates to obtain absolute BFs:
= 0.70 +- 0.15 (where’s the rest?)
New: Ds → m and fDs
c
Ds
Helicity-suppressed leptonic decay:
• feeds interpretation of B, Bs mixing
( Ds  l  l ) 
Analysis Method: “D reco” in e+e- → cc
0
D reco D 
side

Ds
D
*
W

s
• directly related to decay constant fDs
D

GF2 Vcs
8p
2

ml2
2
2

f Ds ml mDs 1  2
 mD
s





Ds*  Dsg  m  m g
Signal peak in M  M D*  M D 
s
s
(normalize to Ds → fp)
BaBar (230fb-1):
f Ds  (279  17 stat  6syst  19 Ds fp )MeV
Lattice QCD:
f Ds  (249  17)MeV
Single best measurement of
decay constant!
( Ds  m  m )  (6.5  0.8  0.3  0.9) 103
f Ds
BaBar
2
 D0 (t ) 
  D0 (t ) 
i  0    M  i  2  0 
t  D (t ) 
 D (t ) 
Do-Do Mixing

Do


Mixing could proceed via
D
o
the presence of d-type quarks in
the loop makes the SM
expectations for Do- Do mixing
small compared with systems
involving u-type quarks in the box
diagram because these loops include
1 dominant super-heavy quark (t): Ko
(50%), Bo (20%) & Bs (50%)
New physics in loops implies
x M/ y  /2; but long range
effects complicate predictions
SM |x|
SM |y|
BSM |x|
From H. Nelson, updated by
A.A. Petrov hep-ph/0311371
D0
Cabibbo favored
K+ppo
Remove


Use Dalitz plot to
enhance Cabibbo
favored rate since it
proceeds largely via Kr+, while wrong-sign
rate goes to K*+p- &
K*opo
Fit for
R
f (t )  RD  a~
y ' RD t  M ( t ) 2
2
Wrong-sign
RD (%)
D mixing results
RM<0.54x10-3 @ 95% CL
Fraction of Cabibbo
suppressed mode
RM consistent with no
mixing at 4.5% C.L.
RM (%)
Mixing parameter
No mixing
e+
Measurements of R=shad/smm e
K+KK0SK0L
6p
2K+4p
K+K-p/h
K0Kp
p+p-
R Units
In solid boxes ready ,
 in dashed boxes in progress .

p+p-p+pp+p-p0p0
K+K-p+pK+K-K+K-
DD*
pp
hep-ex/0509040
p+p-p0
Hadrons
-
2S
J/
s’ [GeV]
Critical region for m
anomalous magnetic moment
Critical region for as
More papers on the topic

Initial State Radiation
hep-ex/0605020 Examination on SK atmospheric neutrino experiment by the computer
experiment

 physics
hep-ex/0604014 Search for the Decay tau- --> 3pi- 2pi+ 2pi0 nu_tau

New States
hep-ex/0603052 Observation of a Charmed Baryon Decaying to D0 p at a Mass Near
2.94 GeV/c2
hep-ex/0604006 Search for the Charmed Pentaquark Candidate Theta_c(3100) in e+eAnnihilations at sqrt(s)=10.58 GeV
Details from J. Coleman tomorrow

Charm and quarkonium Physics
hep-ex/0604031 Observation of $\Upsilon(4S) decays to $\pi^+pi^-\Upsilon(1S)$ and
$\pi^+pi^-\Upsilon(2S)
hep-ex/0605044 Absolute Branching Fraction Measurements for D^+ and D^0
Inclusive Semileptonic Decays
Conclusions: BaBar 3D improvements
creativity
Current errors from B-Factories :
sa~10o
s(sin2b)=0.032
s(g)~20o
s(Vub)/Vub~7.5%
s(Vcb)/Vcb=1.8%
BaBar is actually a flavorfactory: enormous bredth of
physics program
productivity
Always developing new
techniques: current best
methods not in Physics Book
Looking for hints of new
physics
58 results ready for winter conferences,
96 more expected for summer
42 papers submitted to journal since the
start of the fiscal year
BACKUP
sin2a from rr - method
u
B0
b
d
u
d
d
Mixing + T:
bg
b
rr+
t
d
u
B0
u
d
d
P: b,d
To disentangle the Penguin contribution
(unknown |P/T| and relative phase d:
isospin analysis, requires measuring
Amplitudes for B0r+r-, B0r+r-,
B±r±r0, B0r0r0, and B0r0r0 (Gronau
& London)
2a eff  2a   pp
Observables in r+rr- CP asymmetry (time-dep.)
pp  e
id ig
2 ia 1 P / T e e
1 P / T e id e  ig
r+ Cpp  sin(d )
2
Spp  1  Cpp
sin( 2a eff )
Bρρ : measuring a
 4-body (rpp) final states with two vector
intermediate states
 4-body amplitude analysis
 replaced by quasi-two-body approach
 Interferences and higher resonances
studied in detail and found to be
negligible
 Angular and time dependent analysis
 Isospin analysis to get a
ρ+ρ- angular analysis
Only one amplitude seems to contribute
PRELIMINARY
f L ( r  r  )  0.978  0.01400..020
028
signal
bkgd
Approximation: set CT=0 and ST=0
f  (t ) 
e
 t / 
4
1  S L / T sin( mt )  CL / T cos( mt )
+
ρ ρ

Assume only iso-spin conserving strong
interactions


isospin analysis
EW penguins estimated to be ~2o
[CKMFitter, using Buras, Fleisher
EPJ C11, 93 (1999) +Neubert, Rosner Phys. Lett. B441, 403 (1998)]
Neglect I=1 amplitudes : based on Bose-Einstein
statistics and non-obvious for large resonances
Br(rr)
(30±6) 10-6
Br(rr0)
(17±4) 10-6
Br(r0r0)
<1.1 10-6
PRELIMINARY
|aaeff|<11o @ 68%C.L.
Combining pp,ppp and rr from BaBar
a  103
10
9
A New Approach: a from a1?
hep-ex/0603050

(1260)+p
B0
→ a1

Motivated by rr


One of the backgrounds
Another a mode
Observation of B → a1p
9.2s
Little is known about the a1
 Test of factorization
→ take a look!

BF ( B0  a1 (1260) p  )  16.6  1.9  1.5 106

Search for B0 → a1(1260)+r


Background to rr
(in principle) sensitive to a
Dp
New Ideas to Measure sin(2b+g)
Suppress b → c:
B  D(*)0 K (*)0
color-suppressed b → c
Form-factor
suppression
B  D(*)a0( 2 )
b
Enhance b → u:
c
color-allowed b → u
B
0
u
b
d
s
p
(*) 0
D
u
u

K
In all cases: expect
small BR but rB ~ O(1)
All three results are NEW!
More ideas:

(*)
Ds a0,2
A smart idea: TD CP violation with D+a0,2-: large
interference  expect r~1 !!!
Cabibbo suppressed
(iso)spin favored
Cabibbo allowed
(iso)spin disfavored
• Search for Dsa0,2 - SU(3) conjugate (&higher BF) of the
Cabibbo suppressed  measure the unknown form factor
•Assuming factorization [BUT HEAVY MEASON IS EMITTED!]
Theory
Theory papers:
Phys.Lett.B 517,125 (2001)
JHEP 0106:067 (2001)
PRD 67, 014011 (2003)
B0 → Ds(*)+a-0(2): results
hep-ex/0501105
No sign of b → u signal, rB
smaller than expected!
Upper limits much
smaller than
theoretical
predictions!