Measuring the apex: |V ub |, |V cb | and their relative phase γ ( φ 3 )
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Transcript of Measuring the apex: |V ub |, |V cb | and their relative phase γ ( φ 3 )
ICHEP '06 Kowalewski 1
Measuring the apex:Measuring the apex:|V|Vubub|, |V|, |Vcbcb| and their | and their
relative phase relative phase γγ ( (φφ33))
Р. КовалевскиR. KowalewskiU. of Victoria
Canada
γγ
|V|Vcbcb|||V|Vubub||
*
*
cbcd
ubud
VV
VV
ICHEP '06 Kowalewski 2
MotivationMotivation Vub is a key element of the CKM matrix
1 graduate student lifetime (~20 years) ago, we didn’t know that Vub ≠ 0:Was the KM mechanism for CP viable?
Now the precise determination of Vub / Vcb provides a benchmark for testing new physics in other processes
tbtsi
td
cbcscd
iubusud
VVeV
VVV
eVVV
β
cb
ub
V
V
η
ρ
UTFitFPCP 2006
ICHEP '06 Kowalewski 3
Big trees dominate!Big trees dominate!
The decay channels used to study |Vub|, |Vcb| and their relative phase are all dominated by tree diagrams
b
q c, u
ℓ
ν
D0
K-
K-
D0q
Interference allowsphase measurement
Lifetime + semileptonic decay determine |Vqb|
“f”
B
B-
B-
Vq
b
Vcb
Vu
b
ICHEP '06 Kowalewski 4
The magnitudes|Vcb| and |Vub|
tbtsi
td
cbcscd
iubusud
VVeV
VVV
eVVV
ICHEP '06 Kowalewski 5
Semileptonic B decay - Semileptonic B decay - theorytheory Large BF, only one hadronic current
Inclusive decays b qℓν: Weak quark decay + QCD
corrections OPE in s and 1/mb
Exclusive decays B Xℓν: Form factors: need Lattice QCD
Vqb
|Vcb
| and |
Vu
b|
from
sem
ilep
tonic
B
deca
ys
These inclusive and exclusive determinations
of Vqb are complementary
ICHEP '06 Kowalewski 6
Semileptonic B decay - Semileptonic B decay - experimentexperiment Inclusive decays b qℓν:
Measure lepton Measure pmiss or associated hadrons
Exclusive decays B Xqℓν: Measure lepton and specified hadrons
Measurements come from Y(4S)BB
Determine non-B contribution using data below BB threshold
BB
Vqb
|Vcb
| and |
Vu
b|
from
sem
ilep
tonic
B
deca
ys
ICHEP '06 Kowalewski 7
Inclusive |Vcb|
tbtsi
td
cbcscd
iubusud
VVeV
VVV
eVVV
See talk of Urquijo, S10
ICHEP '06 Kowalewski 8
Total decay width for b cℓν:
Similar expressions for b uℓν, b sγ
Comparison with data relies on quark-hadron duality
integrate over “broad” regions of phase space
Inclusive decay widthInclusive decay width
...
m
ρ,
m
ρr,z
m
μ,
m
μr,z
m
0rzμr,AA1
192π
mGVΓ
3b
3LS
3b
3D
32b
2G
2b
2π
2b
0pert
ew3
5b
2F2
cb
free quark decay
Perturbative corrections
Non-perturbative power corrections
~1.014 ~0.908
|Vcb
| fr
om
in
clusi
ve
deca
ys
r = mc / mb
Low-order moments can be calculated reliably
ICHEP '06 Kowalewski 9
Global fit for |VGlobal fit for |Vcbcb|, m|, mbb… … Fit predicted moments of inclusive processes bcℓν and bsγ
for various cuts on kinematic variables:
Calculations available in “kinetic” and “1S” renormalization schemes
47 measured moments used from DELPHI, CLEO, BABAR, BELLE, CDF (and, of course, the B lifetime)
),,,,,,( 33220
00LSDGcb
xnE
nXBEE
nx mmEfdMM
l
b-b-quark quark massmass
e or e or γγ energy energy
cutcutc-c-quark quark massmass
Matrix elements Matrix elements appearing at appearing at order 1/morder 1/mbb
22 and and 1/m1/mbb
33
|Vcb
| fr
om
in
clusi
ve
deca
ys
Benson, Bigi, Gambino, Mannel, Uraltsev
(several papers)
Bauer, Ligeti, Luke, Manohar, TrottPRD 70:094017 (2004)
ICHEP '06 Kowalewski 10
|Vcb
| fr
om
in
clusi
ve
deca
ys
mb (GeV)
μ π2 (
GeV
2)
bsγ
bcℓν
combined
kinetic scheme
χ2 / Ndof = 19.3/44
1S scheme
χ2 / Ndof = 5.7/17
Global fit: resultsGlobal fit: results
|Vcb| determined to <2%
Only sinθc known better!
|Vcb| (10-3) 41.96 ± 0.23exp± 0.35HQE± 0.59ΓSL
mb [kin]
(GeV)
4.59 ± 0.025exp± 0.030HQE
μπ2
[kin]
(GeV2)
0.401 ± 0.019exp± 0.035HQE
[kin]/[1S] values agree after
scheme translation
Buchmüller and Flächer,PRD 73: 073008 (2006) |Vcb| (10-3) 42.0±0.7fit±0.5αs
±0.6th
|Vcb| (10-3) 41.5 ± 0.5fit ± 0.2τB
mb[1S]
(GeV)
4.73 ± 0.05fit
λ1[1S](GeV2) -0.30 ± 0.04fit
mb to 1%; crucial for |Vub|
New!
ICHEP '06 Kowalewski 11
Inclusive |Vub|
tbtsi
td
cbcscd
iubusud
VVeV
VVV
eVVV
See talks of Dubitzky, Schwanda, S10
ICHEP '06 Kowalewski 12
Background bcℓν rate is 50 times signal Restrict kinematics to suppress background: challenge for
theory OPE convergence is compromised:
Need light-cone distribution (shape) function of b quark Relate buℓν directly to bsγ (e.g. Lange, Neubert, Paz, JHEP 0510:084,
2005)
Measure bu rate in regions dominated by bc Theory fine; must fight large
uncertainties from background
Strategies for isolating Strategies for isolating bbuuℓℓνν decays decays
|Vu
b|
from
in
clusi
ve
deca
ys
In all cases sensitivity to mb
N, N»5
q2 (
GeV
2)
Ee (GeV)
bc allowed
Points are buℓν simulation
ICHEP '06 Kowalewski 13
Shape functionShape function bsγ spectrum measured by CLEO, Belle, BaBar
SF moments related to HQE parameters
Subleading shape functionsdiffer in bsγ, buℓν
hep-ex/0607071preliminary
Spectrum in lepton tagged
events
|Vu
b|
from
in
clusi
ve
deca
ys
2π
2
γ2b
γ μEE ,2
mE
γ
ICHEP '06 Kowalewski 14
New measurementsNew measurementsBaBar result: PRL 96:221801 (2006)
Fully reconstruct 1 B meson; study semileptonic decay of other B
|Vub|=(4.43 ±0.38 ±0.25 ±0.29) 10-3
Measure up to mX < 2.5 GeV |Vub|=(3.84 ±0.70 ±0.30 ±0.10) 10-3
|Vu
b|
from
in
clusi
ve
deca
ys
CLEO limit Weak Annihilation contributions: ΓWA / Γbu < 7.4% (90% CL) PRL 96:121801 (2006)
2/
min0 min
max
, to RelateBm
E
sbm
XX
ub dEEEWdE
ddm
dm
d
bu
e+
νIsoscalar hadron
Theory errors are small
Will improve – only 88×106 BB used so far
ICHEP '06 Kowalewski 15
Theory calculationsTheory calculations
Two sets of calculations in use for b sγ and b uℓν
Bosch, Lange, Neubert, Paz (BLNP): 3-scale OPE based on HQET, SCET
Andersen, Gardi (DGE): parton-level calculation, only mb and ΛQCD input
Both provide good description of data; give similar results
Bauer, Ligeti, Luke (BLL): |Vub| using mX-q2 cuts
|Vu
b|
from
in
clusi
ve
deca
ys
PRD 72:073006 (2005)
JHEP 0601:097 (2006)
PRD 64:113004 (2001)
ICHEP '06 Kowalewski 16
Determination of |VDetermination of |Vubub||
Good C.L. = 41% Error budget (in %; total 7.3) :
±2.2stat ±2.8exp ±1.9WA ±1.9b2c model ±1.6b2u model ±4.2HQ param ±3.8sub SF
DGE: (4.46±0.20±0.20)×10-3
C.L. = 12% BLL mX-q2: (5.02±0.26±0.37)×10-3
C.L. = 77% Many measurements use small
fraction of current data samples. Aggressive target for 2008 is 5%
|Vu
b|
from
in
clusi
ve
deca
ys
~ exp
~ theory
|Vub| = (4.49±0.19±0.27)×10-3 (BLNP)
Major progress since last ICHEP
ICHEP '06 Kowalewski 17
Exclusive |Vcb|
tbtsi
td
cbcscd
iubusud
VVeV
VVV
eVVV
See talk of Lopes Pegna, S10
ICHEP '06 Kowalewski 18
Exclusive bExclusive bccℓℓνν decaysdecays Heavy-to-heavy transition; HQ symmetry applies
unique, universal FF, unit normalization at zero recoil
b ceν
before after
Light d.o.f. unchanged!
wwVG
dw
DBd cbF GF48
2
3
22*
phase space
form factors
D* boost in the B rest frame
1.504 1 ;2 *
22*
2
wmm
qmmw
DB
DB
|Vcb
| fr
om
excl
usi
ve d
eca
ys
ICHEP '06 Kowalewski 19
BBDD**ℓℓνν form factor form factor 3 non-trivial form factors; 4 observables:
w and 3 angles HQET-params:
ρ2 = -dF/dw |w=1 , R1 ~ V/A1 and R2 ~ A2/A1
Two measurements from BaBar; averaged values:
ρ2 = 1.179 ± 0.048 ± 0.028 R1 = 1.417 ± 0.061 ± 0.044R2 = 0.836 ± 0.037 ± 0.022
F(1)|Vcb| = (34.68 ± 0.32 ± 1.15)×10-3 BF(B0D*+ℓ-ν) = 4.84 ± 0.39%
|Vcb
| fr
om
excl
usi
ve d
eca
ys
BaBarhep-ex/
0607076preliminary
pℓ (GeV)
BaBar hep-ex/0602023
w
ICHEP '06 Kowalewski 20
|V|Vcbcb| from B| from BDD(*)(*)ℓℓνν
New HFAG average including updated form-factorsF(1)|Vcb| = (36.2 ± 0.8)×10-3
Using
(Quenched LQCD, PRD 66:014503 (2002))
Work needed on both experiment and theory to reach the precisionof the inclusive determination
Similar measurements on BDℓ-ν are harder; in progress
|Vcb
| fr
om
excl
usi
ve d
eca
ys
030.0035.0919.01
F
31.561.24cb 100.8739.4V
(inclusive: |Vcb|=(42.0±0.7)×10-
3
ICHEP '06 Kowalewski 21
Exclusive |Vub|
tbtsi
td
cbcscd
iubusud
VVeV
VVV
eVVV
See talks of Dubitzky, Schwanda, S10
ICHEP '06 Kowalewski 22
B B ππℓℓνν New BaBar B0 π -ℓ+ν
High statistics ν-reco method Significantly improved
precision ISGW2 model: C.L. = 0.07% Data consistent with Lattice
QCD and Becirevic-Kaidalov
0.040.050.53α
100.030.040.37GeV 16qΔBF
100.100.081.44νπBBF
BK
422
4
|V
ub|
from
excl
usi
ve d
eca
ys
4
422
4
100.380.382.91νBBF
100.050.080.40GeV 16qΔBF
100.130.161.37νπBBF
New CLEO B0 π -/ρ- ℓ+ν preliminary Good quality ν-reco
hep-ex/0607060
q2
CLEO preliminary
mπℓν
All q2 combined
ICHEP '06 Kowalewski 23
B B ππℓℓνν with low with low backgroundbackground Reconstruct (tag) one B in
hadronic or semileptonic decay
Compare what’s left with signalBaBar 211 fb-1
Belle 253 fb-1
BF (10-4) Belle hep-ex/0604024 BaBar hep-ex/0607089
π+ℓν (s.l. tag) 1.38 ± 0.19 ± 0.14 1.12 ± 0.25 ± 0.10
π0ℓν (s.l. tag) x2τ0/τ+1.43 ± 0.26 ± 0.16 1.35 ± 0.33 ± 0.19
π+ℓν (had tag) 1.49 ± 0.26 ± 0.06 1.07 ± 0.27 ± 0.19
π0ℓν (had tag) x2τ0/τ+
1.60 ± 0.32 ± 0.11 1.52 ± 0.41 ± 0.20
ρ0ℓν / ηℓν 1.33 ± 0.23 ± 0.18 0.84±0.27±0.21
ρ+ℓν / η’ℓν 2.17 ± 0.54 ± 0.32 <1.3
|Vu
b|
from
excl
usi
ve d
eca
ys
Hadronic tag
Preliminary
π+ℓν π0ℓν
ρ+ℓν π+ℓν
π0ℓν ρ0ℓν
Semileptonic tag
ICHEP '06 Kowalewski 24
(inclusive: |Vub|=(4.49±0.34)×10-3
Experimental error on |Vub|
~ 6%
|V|Vubub| from B | from B ππℓℓνν
For |Vub|: Lattice QCD: q2>16 GeV2
Light-cone sum rules: q2<16 GeV2
FF normalization errors dominate; task for theory, CLEO-c
|Vu
b|
from
excl
usi
ve d
eca
ys
New
New
New
New
New
New
New
New
New
6% uncertainty
Averages of tagged and untagged methods are comparable
FF calc Vub [10-3] FF norm (ps-1) Ref
Ball-Zwicky 5.44 ± 1.43 PRD 71:014015 (2005)
HPQCD 1.46 ± 0.35 PRD 73:074502 (2006)
FNAL 1.83 ± 0.50 hep-lat/0409116
APE 1.80 ± 0.86 Nucl. Phys. B619:565 (2000)
1.360.63 -
0.610.40 -
0.590.41 -
0.560.37 -
0.23 3.54
0.23 3.51
0.26 3.93
0.12 3.38
ICHEP '06 Kowalewski 25
The phase: γ (φ3)
tbtsi
td
cbcscd
iubusud
VVeV
VVV
eVVV
See talks of Marchiori, Krokovny, S8
ICHEP '06 Kowalewski 26
The relative phase The relative phase γγ ( (φφ33))Interference between tree-level decays; theoretically clean
Parameters: γ, (rB, δB) per mode
Three methods for exploiting interference (choice of D0 decay modes):
• Gronau, London, Wyler (GLW): Use CP eigenstates of D(*)0 decay, e.g. D0 Ksπ0, D0 π+ π -
• Atwood, Dunietz, Soni (ADS): Use doubly Cabibbo-suppressed decays, e.g. D0 K+π -
• Giri, Grossman, Soffer, Zupan (GGSZ) / Belle: Use Dalitz plot analysis of 3-body D0 decays, e.g. Ks π+ π-
Vcs* Vub: suppressedFavored: Vcb Vus
*
b
u
s
u u
b
u
cD(*)0
K(*)-
B- B-
u
s
u
c
D(*)0f
Common
final state
K(*)-
iiBKDBA
KDBA eer B
0
0
ICHEP '06 Kowalewski 27
GLW-based analysesGLW-based analyses Measure asymmetry between B+/B- for CP even/odd D decays
and the fractional decay rates to CP eigenstates:
coscos21
sinsin22
BBB
BBCP rr
r
KDBKDB
KDBKDB
coscos21 2
00 BBBCP rrKDBKDB
KDBKDB
Belle 275 106 BB
B+DCP+K+
B+DCP+π+
Signals seen in CP-even and CP-odd D decays
The a
ng
le γ
(φ
3)
Hard to disentangle rB from γ and δB
8-fold ambiguity on γ
Similar measurements exist in B+ D*0 K+
CP-even D0 modes
CP-odd D0
modes
B+DCP-
K+
BaBar 232 106 BB
B+DCP-π+
Recent results: Belle (PRD 73:051106, 2006), BaBar (PRD 73: 051105, 2006)
ICHEP '06 Kowalewski 28
GLW averagesGLW averages
DC
P K
*D
* CP K
DC
P K
The a
ng
le γ
(φ
3)
Implications for rB and γ discussed later
ICHEP '06 Kowalewski 29
ADS-based analysesADS-based analyses
Use DCS decays to reach same final state, e.g.The a
ng
le γ
(φ
3)
π)(KK
π)(KK00
00
nDDB
nDDB
favored suppressed
suppressed favored
Small product BF but comparable amplitudes large potential asymmetry
coscos2
sinsin2
22DBDBDBADS
ADS
DBDBADS
rrrrKKBKKB
KKBKKB
rr
KKBKKB
KKBKKB
DB iδD
iγiδBKπKDBA
KπKDBA ereer
Additional parameters rD and
δD
DCSD charm;rD (Kπ)= 0.0603 ±
0.0025
Direct dependenceModes D*K and DK* also used
D*0 D0π and D*0 D0γ have opposite CP
ICHEP '06 Kowalewski 30
Belle hep-ex/0508048 386 106 BB
[K+π-]D K- [K-π+]D K-
ΔE
ADS resultsADS resultsThe a
ng
le γ
(φ
3)
c.l.) (95% 390.0 DK
New BaBar result in [K+π-
π0]DK-
BaBar preliminaryhep-ex/0607065 226 106 BB
mES
Belle result in [K+π-]DK-
No signal yet in suppressed
modes
c.l.) (90% 140.0 DK Implications for rB and γ discussed later
ICHEP '06 Kowalewski 31
Dalitz analysesDalitz analyses Measure B+/B- asymmetry across Dalitz plot
Includes GLW (D0 Ks ρ0, CP eigenstate) and ADS (D0 K*+π-, DCS 2-body decay) regions
The a
ng
le γ
(φ
3)
2222 ,,
mmfeermmfA BiiB
KKB Ds
Sensitivity to γ in interference term
2-fold ambiguity on γ: (γ, δ)→ (γ+π,
δ+π)
decay amplitude
Determine f in flavor-tagged D*+D0π+ decays
sKmm 22Mirror symmetry
between D0 and D0 Dalitz plots
ICHEP '06 Kowalewski 32
Dalitz model for KDalitz model for Kssππ++ππ--
Select D*+[Ksπ+π-]π+ from e+e- cc; ~4 105 events
Fit to coherent sum of 15-16 Breit-Wigneramplitudes plus a non-resonant term
The a
ng
le γ
(φ
3)
m2+
(GeV2)
m2- (
GeV
2)
Belle 357 fb-1
preliminaryhep-ex/0604054
BaBar 270 fb-1
preliminary
m2(π+π-) GeV2
Excellent fits obtained
Main contributors:
• K*-(892) π+
• Ks ρ0
• K*0(1430) π -
• K*-(892) π+
• non/broad resonant
Model-independent approach (GGSZ) using CP-tagged D0 studied by Bondar, Poluektov in hep-ph/0510246
Improved modeling (e.g. K-matrix formulation) under study
ICHEP '06 Kowalewski 33
Plots shown are representative; both experiments have analyzed DK, D*K and DK* decays
Dalitz plotsDalitz plotsThe a
ng
le γ
(φ
3)
Belle hep-ex/0604054
D*K-
386 106 BB
D*K+
347 106 BB
BaBar preliminary
DK-DK+
ICHEP '06 Kowalewski 34
Results on Results on γγ
HFAG averages for x± = rB cos( δB ± γ ) , y± = rB sin( δB ± γ ) UTfit find γ = 78±30° based on B- D(*) K(*)- decays Note: σγ depends significantly on the value of rB
The a
ng
le γ
(φ
3)
Contours do not include Dalitz model errors
Contours do not include Dalitz model errors
rB
2γ
ICHEP '06 Kowalewski 35
sin(2sin(2ββ++γγ))The a
ng
le γ
(φ
3)
Parameters: γ, 2β
(r, δB) per mode
Vcd* Vub: really suppressedreally favored: Vcb Vud
*
b
d
d
u b
d
d
cD(*)+
π-
B0 B0
c
d
d
u
D(*)-
2 common final states
via BB mixing
π+
2
favored
suppressed iiB eer
A
AB
Large BF but small rB (<2%) small CP
asymmetry
rB must be estimated from
B0Ds+π – using SU(3)
Time-dependent effect
(due to B0-B0 mixing)
ICHEP '06 Kowalewski 36
BB00 D D00 K K00 feasibility study feasibility studyThe a
ng
le γ
(φ
3)
BaBar hep-ex/0604016, soon in PRD
• Interference of B0 D0 K0 withB0 B0 D0 K0 (K0 and K0 mix)
• Determine rDK* in related decay B0 D0 K*0
• BaBar find no signal: rDK* < 0.4 @90% c.l.
• This mode may be harder to use for sin(2β+γ) than predicted; implications for LHC-b
B0D0
K*0
Vu
b
B0 D0 K*0
ΔE
B0D0
K*0
Vcb
ICHEP '06 Kowalewski 37
Related measurementsRelated measurements
BaBar PRD D73 \:071103 (2006)
c.l. 90% ,10
20
19
6.3
9.1
5
2*
2
0*
0
aDBBF
aDBBF
aDBBF
aDBBF
s
s
s
s
B0 Ds a0,2
Nice ideas, nice work, but not much impact
yet for γ
226 106 BB
rDπ from B0Ds(*)π -,
SU(3)
2
5
*
*
102.02.09.1
1.02.03.1
10
4.05.00.2
4.04.05.2
5.06.08.2
2.03.03.1
*
D
D
s
s
s
s
r
r
KDBBF
KDBBF
DBBF
DBBF
BaBar hep-ex/0604012, 226 106 BB
preliminary
BD*D*
The a
ng
le γ
(φ
3)
BF and charge asymmetries measured for all B D(*)D(*)
modes; provides input for sin(2β+γ) from B0 D(*)+D(*)- time-dependent asymmetries
BaBar PRD 73:112004 (2006)
BaBar show that B D0
K+π- not promising for measuring γ
BaBar PRL 96:011803 (2006)
B0 D0 K+ π -
ICHEP '06 Kowalewski 38
Current status of UTCurrent status of UT
Tree-level determination: information on phase γ (φ3) not yet constraining
All constraints: compatible with SM, but tension exists between sin2β and |Vub/Vcb|
The a
ng
le γ
(φ
3)
“2-σ” bands
See talks of Vagnoni, T’Jampens, S8
ICHEP '06 Kowalewski 39
SummarySummary Today:
What to look for in 2008: 2 ab-1 from the B factories
(>doubling of data sample) error on |Vub/Vcb| of ~5%
error on γ: ~10-15° ? (rB …) LHC-b will have initial data
The heavy flavor program will restrict the space in which theories for the new physics to be seen at LHC can operate
3078)(φγ
1027.019.0494.V
1069.023.00.24V
3
3ub
3cb
“2-σ” bands
ICHEP '06 Kowalewski 40
Backup slides
ICHEP '06 Kowalewski 41
Tale of two fittersTale of two fitters
CKMfitter (frequentist)
UTFit (Bayesian)
ICHEP '06 Kowalewski 42
Theory calculationsTheory calculations
Bosch, Lange, Neubert, Paz (BLNP) Decompose into Hard, Jet and Shape functions using HQE
and SCET: H×J ×S Same formalism used to extract mb and μπ
2 from bsγ Predictions over full phase space, reasonable error analysis Critique: 3 scales between ΛQCD and mb
Andersen and Gardi: Dressed gluon exponentiation (DGE) Only mb and αS as input parameters Gives good description of bsγ spectrum Agrees fairly well with BLNP on buℓν rates Critique: some (but not all) consider it a model;
|Vu
b|
from
in
clusi
ve
deca
ys
ICHEP '06 Kowalewski 43
Global fit: Input Global fit: Input measurementsmeasurements
Moments used in fit, from B Xcℓν and b sγBuchmüller and Flächer,Phys.Rev. D73 (2006) 073008
\ MomentExperiment
Electron energy
Hadronic mass Photon energy
Delphi 3 3
CLEO need full covar 4 1
CDF 2
Belle need full covar need full covar 4
BaBar 14 13 3
|Vcb
| fr
om
in
clusi
ve
deca
ys
ICHEP '06 Kowalewski 44
BBXXccℓℓνν using using
tagged samplestagged samples Reconstruct D(*)Xℓ-ν across from a fully reconstructed
B+ or B0 meson; Mmiss2 provides new kinematic handle
Belle reported last year BFs for B D(*)πℓν: Phys.Rev.D72:051109,2005 Also report BF(B-D*0ℓ-ν) = 6.06 ± 0.25stat%;and BF(B0D*+ℓ-ν) = 4.70 ± 0.24stat%.
New BaBar preliminary result:BF(B-D*0ℓ-ν) = 6.8 ± 0.4%BF(B-D0ℓ-ν) = 2.3 ± 0.3%BF(B-D**0ℓ-ν) = 1.9 ± 0.3%(includes D(*)πℓν; translated from relativefractions into BFs by this speaker assumingthese modes saturate bcℓν)
New D0 result (preliminary)BF(BsDs1(2536)ℓν) = 0.86 ± 0.16 ± 0.16
BelleBF (in %)|V
cb|
from
excl
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ve d
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ys
D
D*
D(*)π
ICHEP '06 Kowalewski 45
The BF(BThe BF(BDD**ℓℓνν) puzzle) puzzle The largest B BF is BD*ℓν (~6%), yet B K*γ (~4×10-5) is
known as well, and perhaps better…
(HFAG winter) average: BF(B0D*+ℓ-ν) = 5.35 ± 0.20%; CL=3.8%
Consider RD* = BF(B-D*0ℓ-ν) / BF(B0D*+ℓ-ν); we expect RD* = τ+ / τ0 = 1.071 ± 0.009
Naively combining Belle and BaBar results: RD*
= 1.32 ± 0.07(20% and 3.5σ from isospin!)
|Vcb
| fr
om
excl
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BaBar preliminary
Ee
BF(B+Xeν) / BF(B0Xeν)= 1.084 ± 0.041 ± 0.025
Total BF(BXℓν) consistent with isospin
ICHEP '06 Kowalewski 46
Importance of rImportance of rBB
The uncertainty on γ (φ3) depends strongly on the value of rB, which is currently not well known
Predictions for how σγ will evolve with luminosity have significant uncertainty
rB
φe
Belle