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Rare and Semileptonic Decays of B and K Mesons. Particles and Nuclei International Conference Santa Fe, Oct. 27, 2005. Jeffrey D. Richman University of California, Santa Barbara B A B AR Collaboration. Outline. Goals and challenges K L p 0 nn - PowerPoint PPT Presentation
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Rare and Semileptonic Decays of B and K Mesons
Jeffrey D. RichmanJeffrey D. RichmanUniversity of California, Santa BarbaraUniversity of California, Santa Barbara
BBAABBAR CollaborationAR Collaboration
Particles and Nuclei International ConferenceSanta Fe, Oct. 27, 2005
Goals and challenges
KL0
The “kaon revolution”: KL e- , |Vus|, and the recalibration of kaon branching fractions
Electroweak penguin/box diagram processes: BK*, B, BXs and BK l+l-, BK* l+l-
Semileptonic B decays and the measurement of |Vcb |, |Vub |, mb, mc
[Leptonic B decays: Bs+B+ ] Perspective and conclusions
Outline Outline
Far too many topics to cover... my apologies! Parallel session talks contain manymore details (Bizjak, Godang, Koeneke, Mohapatra,…)
Rare decay: loop/box process test SM at 1-loop level new (heavy) particles can be produced in virtual intermediate states; can compete with SM amps search for effects of new physics
Semileptonic decay: tree diagram measure |Vij| determine quark masses, QCD parameters
W
, b s,c u
d d
Rare and Semileptonic Decays: GoalsRare and Semileptonic Decays: Goals
ijV
b , ,u c t
W
,s d
d d
Common theme: understanding dynamicsCommon theme: understanding dynamics
• Amplitude factorizes single hadronic current• Form factors/QCD parameterscan sometimes be extracted from data or be calculated• Precise rate predictions possible
for some processes• Methods: HQET, heavy-quark expansions, lattice QCD,…
b , c u
B
Z0K
ub BV f
W
B
b
u
0s
Wd
dd
W
t
Understanding dynamics is an important goal in itself!
212
2 412
2
2
3
3
1 ( )
1 ( )
(1 ) 1
0.97 0.23 0.004
0.23 0.97 0.04 (leaving out phases)
0.008 0.04 1
ud us ub
cd cs cb
td ts tb
V V V A i
V V V A O
V V V A i A
CKM matrix: CKM matrix: bb and and ss decays are both suppressed! decays are both suppressed!(Wolfenstein parametrization)
5 highlighted Vij: discuss in this talk!
*
*ud ub
cd cb
V V
V V
*
*td tb
cd cb
V V
V V
2 ( )
1 ( ) 3 ( )
( , )
(0,0) (1,0)
*Col(1) Col(3) 0
unitarity:6 triangles, allwith same area
0 0 0 0S S SB K K K BABAR
Buras, Schwab, & Uhlig, hep-ph/0405132; very small theory errors achievable.
KKLL00
d
d
Z
s
d
W
t
0K tsV *tdV
• KL decay directly measures height of unitarity triangle)!
• SM prediction: • Use K+0 e+ measurement to compute hadronic current.
tsV *tdV
sd d
d
0 0 * * 2 5( ) ( )L ts td ts tdAmp K V V V V A
* 2 3( ) ( ) (1 )ts tdV V A A i
0K
t
W W
0 0 11( ) (3.0 0.6) 10L SMB K
11( ) (7.8 1.2) 10SMB K 1.30 10
787 / 949 0.89( ) (1.47 ) 10E EB K E949, PRL 93, 031801 (2004)
0
• Prelim. result uses 1.14 x 109 KL decays; =0.73x10-2 • So far, only very small fraction of data used. • No events observed in signal box
• E391a goal
• Proposal in preparation for follow-on experiment at
J-PARC
Preliminary results on Preliminary results on KKLL00 from KEK E391a from KEK E391a
(90% C.L.)
2. Reconstruct decay vertex assuming
M=M(0).
3. Signature: z(vertex) and pt
0 0 7( ) 2.86 10LB K
0 0 9( ) 1.4 10LB K
0 0 0
0
LK
n X Y
Major backgrounds
1. Measure position and energy in CsI
KKee , | , |VVusus|, and the “kaon revolution”|, and the “kaon revolution”
2 52 2 2 2
3 23(1 ) ( 0)
192F K
K us EW K SU K
G MV S C f q I
W
s u
d d
usV
long distance rad. corrections
I-spin corr.for K+ decay
KLe: 1K+e:1/2
form factortheory: q2=0exp’t: shape
2 2 21 0.0043 0.0019ud us ubV V V
0.0104 0.002
0.019 0.003
0.0006 0.002
L
L
eK
K
e
K
Review of Particle Properties, 2002
Cirigliano et al.,Eur.Phys. J C35, 53 (2004)Andre, hep-ph/0406006
Leutwyler & Roos, Z.Phys.25, 91 (1984)
short distanceradiative corr.
1.022EWS
Sirlin, Nucl. Phys. B196, 83 (1982)
0.9734 0.0008udV
0.2196 0.0023usV
+other work in progress
experiment: BR,
Recalibration of Recalibration of KKLL branching fractions branching fractionsKTeV measured 6 largest KL modes [PRL 93, 181802-1 (2004)]
• Account for 99.93% of decays; 5 ratios of branching fractions • 105-106 events/mode; careful treatment of radiation from electrons.• Measurement of KL semilep form factors (1.7%-4.2% shifts) [hep-ex/0406003, 0406006]
LK e
0 0 0LK
LK
LK
0LK
0 0LK
E. Blucher, Lepton-Photon 2005fit to all new meas.
Extraction of |Extraction of |VVusus||
Average of recent results: • KLOE, KTeV, NA48, ISTRA+• correlations taken into account
E. Blucher, Lepton-Photon 2005
(0) 0.2173 0.0008usV f (0) 0.961 0.008f
0.2261 0.0021usV
Competing method: (K++ [KLOE, hep-ex/0509045] + lattice [MILC,
PRD70, 114501 (2004); Marciano, PRL93, 231803 (2004)]
0.2223 0.0026usV
2 2 21 0.0004 0.0011ud us ubV V V (0)usV f
b , ,u c t
W
,s d
d d
Radiative penguin decays of Radiative penguin decays of BB mesons mesons
Observation of BK* CLEO II (1993): Loops in B decays!
6(10 )B
*( )M K
*
5
( )
4 10
B B K
PRL 71, 674 (1993)cited >500 times!
Now it’s a physics program!
Observation of theObservation of the b bdd decaysdecays B B
0.026 0.0380.025 0.0290.200td
ts
V
V
*
*
32 2(
2
, ) 232 2
( ( , ) )
( )
1 / 1
1 /
td
t
B
BsK
B B
B B K
m mR
m
V
V m
Ali, Lunghi, Parkhomenko, PLB 595, 323 (2004)
0.85 0.10
0.1 0.1
Belle
8.2 evts
20.8 evts
5.9 evts
Belle, 386 M BB hep-ex/0506079
BABAR, 211M BB PRL 94, 011801 (2005)
good agreementw/global CKM fit
ModeMode BABAR BABAR (10(10-6-6) ) (2.1(2.1 signif.) signif.)
Belle (10Belle (10-6-6) ) (5.5(5.5 signif.) signif.)
0 0B
B
0B
0.35 0.090.31 0.081.17
0.43 0.120.37 0.110.55
0.4
1.8
1.0 0.34 0.140.31 0.100.58
Belle
BABAR PRD 72, 052004 (2005)
• Canonical process for testing the SM at 1 loop level• Provides powerful constraints on new physics models• Major effort by theory community to compute QCD and EW corrections; NLL calculation complete; NNLL calculation forseen
Belle, PRL93, 061803 (2004)
fully incl.
sum of 38 excl.modes
Hurth, Lunghi, Porod, Nucl. Phys. B 704, 56 (2005); see also Neubert, Eur.Phys. J C40, 165 (2005); Buras et al., Nucl.Phys. B631, 219 (2002)
Inclusive Inclusive BBXXs s Decay Decay
E E
4/( ) (3.70 0.35 | 0.02 | 0.25 | 0.15 | ) 10
c bs m m CKM param scaleB B X
0.30 40.27( ) (3.39 ) 10sB B X HFAG July 2005
*K
Moments of Moments of BBXXss Photon Energy Spectrum Photon Energy Spectrum
Minimum Eγ (GeV)
hep-ex/0507001
1st Moment (GeV) 2nd Moment (GeV2)
Minimum Eγ (GeV)
D. Benson, I.I. Bigi and N. Ultrasev Nucl. Phys. B 710, 371-401 (2005)
(see talk by Karsten Koeneke, Section VI.4)
Used in determination of mb, |Vcb |, and | Vub |
b s
d d
, Z
b, ,u c t
s
d d
Electroweak penguinsElectroweak penguins B BKlKl++ll-- and and BBKK**ll++ll--
BABAR hep-ex/0507005 (229M BB) Belle prelim. hep-ex/0410006, 0508009
B K *B K
• With l+l- pair, can produce both pseudoscalar and vector mesons• New physics can affect both rate and kinematic distributions.
W W
W
, ,u c t
BBKlKl++ll-- and and BBKK**ll++ll- - : branching fractions : branching fractions
Theory errorsmainly due to form factors.
(rarest observed B decay) 6 (10 )
6( ) (0.45 0.05) 10WAB B K
* 6( ) (1.18 0.17) 10WAB B K
2q2q
pole at low q2
BBKK**ll++ll--: : Lepton F-B AsymmetryLepton F-B Asymmetry
Bl
l
s
q*K
l
Lepton angular distribution in ll rest frame
hep-ex/0508009Belle: lepton A(FB) [raw]
2q
386 M BB
SM
NP scenarios
constraints on Wilson coeffs describing short-distance physics
FBA
Precision measurement of |Precision measurement of |VVcbcb|| and the atomic and the atomic physics of physics of BB mesons mesons
s
s
3exp HQE th
exp HQE
exp HQE
exp HQE
(41.4 0.4 0.4 0.6 ) 10
(10.61 0.16 0.06 )%
(4.61 0.05 0.04 0.02 )GeV
(1.18 0.07 0.06 0.02 )GeV
cb
c
b
c
V
m
m
Bs
s
s
s
2 2exp HQE
2 2exp HQE
3 3exp HQE
3 3exp HQE
(0.45 0.04 0.04 0.01 )GeV
(0.27 0.06 0.03 0.02 )GeV
(0.20 0.02 0.02 0.00 )GeV
( 0.09 0.04 0.07 0.01 )GeV
G
D
LS
BABAR, PRL 93, 011803 (2004)
22
3
5
23 3 3 3
34
2 2
42 30 2
( ) (1 ) ( , )192
( ) 1 2(1 ) ( ) (1/ )2
b
b bb
b b b
FSL c cb ew pert
D LS DG
S
DG
L
m
m mm
m
GB X l V
m m
A A r
z r r d r O
Observables• inclusive semileptonic rate• inclusive lepton-energy spectrum (moments)• inclusive recoil hadron mass spectrum (moments)
Heavy-quark expansion theory params: |Vcb|, mb, mc, , G , D , LS
Benson, Bigi, Mannel & Uraltsev, hep-ph/0410080Gambino & Uraltsev, Eur.Phys.J. C34, 181 (2004)
chromomagnetic expec. value
kinetic expec.value
Darwin term
spin-orbit
2( / )c br m mkinetic scheme
||VVcbcb| and inclusive parameters from | and inclusive parameters from BBXXccll and and BBXXss
Buchmuller and Flacher; hep-ph/0507253• Fit to moments of inclusive distributions in BXc l and BXs • Experiments: BABAR, Belle, CDF, CLEO, DELPHI
3(41.58 0.45 0.58) 10cbV
4.591 0.040 GeVbm
(GeV)bm bm
2
2(GeV )
3(10 )
cbV
<2%errors
1.5 31.7(41.2 1.0 ) 10cbV D*l
zero rec.kinetic mass scheme
b s
b c
b c
all moments
all moments
Measuring |Measuring |VVub ub | is hard, but the error is shrinking| is hard, but the error is shrinking
BABAR hep-ex/0509040
bu
continuum data (off res)
bc subtraction
BBrecoreco
BBrecoilrecoilXXuu ll
ee--
DD**
ee++
( )0.1 2%
( )ub u
cb c
V B X
V B X
Lepton spectrum endpoint analysis Fully reconstructed B recoil analysis
Large bc background; suppression cuts introduce dependence on theory predictions for kinematic distributions.
Belle hep-ex/0505088
( )uM X 2q
||VVub ub | inclusive measurements| inclusive measurements
• Key CKM constraint
• Use mb and QCD parameters extracted from inclusive BXc l and BXs spectra.• Many methods with uncertainties around 10%. • Uncertainty from mb has been reduced to 4.5%.• With more data, the |Vub| uncertainties could be pushed down to 5%-6.5%.
2 2ub
cb
V
V
mX vs. q2
Eℓ endpoint
mX
Eℓ vs. q2
3
WAvg(4.38 0.19 0.27) 10ubV
expt mb, theory
u
q
2 2maxq q
uq
2 2minq q
HPQCD: hep-lat/0408019
Fermilab/MILC: hep-lat/0409116
f+(q2) is relevantform factor forB l l=e
HPQCD
Fermilab/MILC
restricted q2 range
At fixed q2, lepton momentum spectrum is exactly known in this mode, since only one form factor.
2q
BB00 l l-- form-factor predictions form-factor predictions
Measuring |Measuring |VVubub| using | using BB ll and lattice QCDand lattice QCD
B l branching fraction and q2 distributionBecher and Hill, hep-ph/0509090
Relatively flatdistribution in spite of rapidly changing form factor.
Consequence of p3 factor in decay rate.
HFAG averages
0 4( ) (1.35 0.08 0.08) 10B B 0 4( | 16) (0.40 0.04 0.04) 10B B q
2 0.67 30.46(HPQCD; 16) (4.47 0.30 ) 10ubV q
2 0.65 30.43(FNAL; 16) (3.78 0.25 ) 10ubV q
Search forSearch for B Bss++-- and and BB00ll++ll--
Highly suppressed in the SM• • Bd suppressed by |Vtd/Vts|2
• No SM signals expected at Tevatron or at B factories, but can have large enhancements from new physics.
9( ) (3.5 0.9) 10sB B
SM predict.SM predict. CDFCDF D0D0 BABARBABAR BelleBelle
-- --sB
dB
dB e e
71.6 10 73.0 10 93.5 1088.3 10 86.1 10
11(10 )O
15(10 )O
83.9 10 71.9 10
71.6 10
WWZ
b W
W s
t
b
bt
0 0H A
6
4
tan( )s
A
B Bm
W W Z
Strong correlation withneutralino-proton crosssection in mSUGRA!Beck,Kim,Ko hep-ph/0406033
K Physics• Early results from 1st dedicated KL experiment• KL branching fractions re-measured: 5% to 8% shifts• |Vus| shift: +3% • Unitarity of 1st row of CKM matrix looks better; work in progress
on |Vud|
B Physics• B observed; provides interesting constraint on |Vtd|/|Vts|• Many bs and bsl+l- modes observed; studies of kinematic distributions are especially interesting• |Vcb| measured to 2% via inclusive method; mb well determined• |Vub| precision now below 10%. • Keep pushing inclusive vs. exclusive crosscheck!• Leptonic B decays providing interesting sensitivity to new physics • B factories will push to 1 ab-1. Many more results to come!
Perspective/ConclusionsPerspective/Conclusions
Backup slidesBackup slides
Huge program on B decays to charmless hadronic final states...
(10-6)
see H. Jawahery talk for hadronic bs decays
6/10B
Observation of theObservation of the b bdd decaysdecays B B
Note: naïve expectation is (B++(B00(B0BABAR/Belle discrepancy on B00; to be resolved with more data.
BABAR Belle
0 0 0 0S S SB K K K BABAR
BBXXss New Physics Sensitivity New Physics Sensitivity• Constraints on Two Higgs doublet models (Type II)• mH = charged Higgs mass• tan = ratio of vacuum expectation values of the two doublets• Hou [PRD48, 2342 (1993)], Gambino & Misiak [Nucl. Phys
B611, 338 (2001)], Neubert [Eur. Phys. J C40, 165 (2005)].
(GeV)Hm
tan tan
90% C.L. allowedregions (above lines)
current BABAR data future projections
B
sB X
combined
sB X B
2 ab-1
0.5 ab-11 ab-1
Search for leptonic Search for leptonic BB-- decaysdecays
Non-relativistic mesons (2 heavy quarks): 22 12 (0)Mf M
ubV W
B
b
u
• helicity suppressed• CKM suppressed (Vub) • annihilation diagram• tree-level sensitivity to H-
22 22 2 2
2( ) 1
8F
Qq qQ M
G mM V f M m
M
meson B (e) B () B ()
KK++
BB++
41.2 10 99.99%51.2 10 63.5%111.1 10 74.8 10 41.1 10
Predicted leptonic branching fractions: (|Vub| = 0.0039, fB = 200 MeV)
Search for Search for BB--
SMSM BABARBABAR (232 M BB) (232 M BB) Belle (275 M BB)Belle (275 M BB)
B(B+
42.6 10 (90% C.L.)
Belle, hep-ex/0507034
BABAR, hep-ex 0507069 reconstruction: a major challenge• fully reconstruct other B in event• require lepton (or pion) and no additional observed energy (2-3)
ee--
ee++
recB
B
eee-
Eextra
ee
Backgrnd Backgrnd
Expected signal x10
41.8 10 (90% C.L.) 41.1 10
Search forSearch for B Bss++-- and and BB00ll++ll--
Highly suppressed in the SM• • Bd suppressed by |Vtd/Vts|2
• No SM signals expected at Tevatron or at B factories, but can have large enhancements from new physics.
9( ) (3.5 0.9) 10sB B
SM predict.SM predict. CDFCDF D0D0 BABARBABAR BelleBelle
-- --sB
dB
dB e e
71.6 10 73.0 10 93.5 1088.3 10 86.1 10
11(10 )O
15(10 )O
83.9 10 71.9 10
71.6 10
WWZ
b W
W s
t
W W Z
90% C.L.
BBss++--and SUSYand SUSY
b
bt
0 0H A6
4
tan( )s
A
B Bm
Dark matter cross section (p) vs. B(Bs+-).
Dermisek, Raby, Roszkowski, Ruiz de Austri, hep-ph/0507233
Baek, Kim, Ko, hep-ph/0406033
Experiment vs. Lattice: Experiment vs. Lattice: DDKK ll form factorform factor
Measuring |Measuring |VVubub| using | using BB ll
BABARProjection to 1 ab-1 (data taken to be on BK fit curve from present measurement).PRD 72, 051102 (2005)
In the high q2 region alone, we will measure the branching fraction with an uncertainty of (6-7)% , or (3-3.5)% uncertainty on |Vub |. Lattice theorists expect to reach 6%, so exclusive/inclusive will be similar.
Precision measurement of |Precision measurement of |VVcbcb|: fits to moments of |: fits to moments of lepton spectrum and hadron recoil spectrum lepton spectrum and hadron recoil spectrum
mX moments
Eℓ moments
● = used, ○ = unusedin the nominal fit
Red line: OPE fitYellow band: theory errors
BABAR
2/ndf = 20/15
BABAR PRL 93:011803 (2004)