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Flavor Changing Neutral Current Decays
Flavor Changing Neutral Current decays, bs, bsll Forbidden at tree level induced through Penguin or Box diagrams at lowest order sensitive to heavy particles (SUSY, heavy Higgs)
Observables Decay Width (Branching Fraction)
Inclusive decay, theoretically clean, experimentally hard. Exclusive decays, large uncertainty due to form factor
test of QCD in B decays
Ratio of Decay Width Some theoretical and experimental uncertainties cancel Good probe also for exclusive decays!
CP Asymmetry Isospin Asymmetry Up-Down Asymmetry BF ratio of electron mode to muon mode Forward-Backward Asymmetry
Penguin diagram in the SM
Beyond the SM diagram
OPE and Wilson Coefficient
Effective Hamiltonian is expressed in term of Operator Product Expansion.
O1,2: current current operator O3-6 : QCD penguin operator O7,8 : electro- and chromo-magnetic operator O9,10 : semileptonic operator Ci : Wilson coefficient
Wilson coefficient is a strength of corresponding short distance operator.
Precise measurement of Wilson coefficients is one of the goals for B physics.
For bs and bll case, only O7, O9 and O10 appear in the Hamiltonian.
New Physics changes the Wilson Coefficients
bs and bsll decays
eff eff eff eff eff *9 10 7 7 9
22 5 *22
3
2 2 2
ˆ1ˆ 4 48
2ˆ1 2 4 1 12Re
ˆ
F b ts tbem
C
d b s G m V Vs
ds
s C C Cs
C
22 5 *
2
3eff732
F em b ts tbG m Vs C
Vb
can be extracted from B(bs), B(bsll) and AFB (bsll) !7 9 10, andeff eff effC C C
Decay widths for bs and bsll can be described with Wilson coefficients.
Absolute value of can be measured.
7effC
Interference terms
(sometimes we do not use Ci but Ai which is leading coefficient)
Relative signs can be also determined from interference terms!!
In the SM
Branching Fraction of BK*
bs was observed at CLEO in K* K* is reconstructed from 4 modes
K+-, Ks0, K+0 , Ks+
|MK* MK| < 75MeV
Better than 10% accurary! Theoretical preduction
QCD fact. (70 25) 10-6
LEET (68 23) 10-6
pQCD (35 10) 10-6
Lattice (35 16) 10-6
B(B0 K*0) = (40.9 2.1 1.9) 10-6
B(B+ K*+) = (44.0 3.3 2.4) 10-6
Theoretical uncertainties are large 80/fb data
K*
K2*(1430)
Asymmetry in BK*
Isospin Asymmetry 0+ is sensitive to sign of Wilson coefficients C6/C7
0+ = +5~10% and C6/C7 >0 in the SM
If C6/C7<0, 0+ <0.
Direct CPV is less than 1% in the SM 5% CPV is allowed in new physics
ACP = (-0.1 4.4 0.8)%
0+ = (+3.4 4.4(stat) 2.6(syst) 2.5(f+-/f00))%
)(B)(B
)(B)(B**00
**00
0
0
0
KBKB
KBKB
B
B
B
B
B0 B0
A.Kagan and M.Neubert, PLB 539, 227 (2002)
Time dependent CPV in BKs0
Not only the K*0, but any Ks0 can be used for TCPV measurement.
In the SM, S<0.1, A<0.01. Right handed currents induce large value of S
S corresponds to fraction of C7R to C7L
MKs < 1.8GeV
tmAtmS
KtBKtB
KtBKtBA
SS
SSCP
cossin
)()(
)()(000
000
0000
00
)(11.0)(38.0
46.058.0)( 00 syststatKS S
)(11.0)(34.003.0)( 00 syststatKA S
250/fb data
K* K2*(1430)
Atwood, Gershon, Hazumi, Soni PRD71 (2005) 076003
First Measurement
Observation of BK
Ks can be used for time dep. CPV measurement to search for right handed currents.
BK+, Ks is reconstructed from and 0
MK < 2.4GeV
6
9.0
2.1 105.14.8)(B
KB
6
6.1
9.1
7.2
1.300 104.8)(B
SKB
First Observation
250/fb data
%6916)(A KBCP
B0 B0
Observation of BK1(1270)
BK final state via K1 can be used for up-down Asymmetry to search for right handed currents. K1(1270) is reconstructed from K++- and Ks+-.
0.6< M < 0.9GeV ( mass region) to enhance K1(1270) Resonance components are extracted by fitting to the hadronic mass
distribution. First Observation 5
1 109.09.03.4))1270((B KB
51 105.1))1400((B KB
140/fb data
501
0 108.5))1270((B KB
M.Gronau et al. PRL88 051802 (2002)
Observation of Bp
Baryon production via weak decay of meson
Near threshold enhancement of di-baryon system is observed in Bp (bs process)
Near threshold enhancement also observed Fragmentation?
First Observation
6
53.0
58.0 1020.016.2)(B
pB
140/fb data
Theoretical prediction ~10-6
Inclusive BXs
Full inclusive b Photon with E>1.8GeV Veto photons from 0 and Subtract continuum with off-resonance data Moment analysis to extract HQET paramet
er
<E> = 2.289 ± 0.026 ± 0.035 GeV
<E2> - <E>2 = 0.0311 ± 0.0073 ± 0.0063 GeV
140/fb data
HQET parameter2
05.0
08.0 GeV/c66.0
used to extract Vcb and Vub
BF of Inclusive BXs
Subtract bd assuming B(bd)/B(bs) = 3.8 ± 0.6%
Measured BF is consistent with theoretical predictions. MH+ >200GeV 95%CL (M.Neubert CKM2005)
Limit on Wilson coefficient A7 -0.36 < A7 < -0.17 or 0.21< A7 < 0.42 In the SM A7 = -0.33 at = 2.5GeV
410))(07.0
11.0)(
31.0
30.0)(32.059.3()(B
theosyststatXB s
G.Hiller and F.Krueger
PRD 69 (2004) 074020
Exclusive BXs / Inclusive bs
40% of bs are measured exclusively. Next step : B0K0S0for TCPV analysis.
K’, Kf0, Ka0…..
K*
K1(1270)
K2*(1420)
K*
KK
Kp
59 ±6.0% missing
Isospin symmetry for B and K* decay is assumed
Search for B
bd process has not been observed Simultaneous fit to B--, B00 and B0
From isospin relations:
constrain |Vtd/Vts|
B(B- -) = 2 ((B-)/(B0)) B(B0 0) = 2 ((B-)/(B0)) B(B0 )
B(B(,)) = B(B-) < 1.4 10-6
250/fb data
SM predictions: B(B--) = (0.90 ± 0.34) 10-6 (Ali-Parkhomenko) B(B--) = (1.50 ± 0.50) 10-6 (Bosch-Buchalla)
Rmm
mm
V
V
KB
B
BK
B
ts
td
1
)/1(
)/1(
)(B
)),((B 2322
322),(
2
*2
22.0ts
td
V
V
R : form factor ratio
: SU(3) breaking effect
Just above the SM prediction!!
Inclusive BXsll
Semi-inclusive technique Electron or muon pair
Mll>0.2GeV Charmonium veto
Xs is reconstructed from K+ or Ks + 0-4 (at most one 0 is allowed) MXs < 2.0 GeV
140/fb data
687.083.0 1030.104.4)(B
eeXB s
685.081.0 1005.113.4)(B
sXB
685.081.0 1083.011.4)(B
sXB
61070.02.4)(B sXB
Theoretical preduction by Ali et al.
Wrong flavor
MXs q2
Limit on Wilson Coefficients
Clean prediction of BF of B(BXsll) for 1<q2<6GeV2 is available. Combine Belle and Babar results Sign of C7 flipped case with SM C9 and C10 value is unlikely.
P.Gambino, U.Haisch and M.Misiak PRL 94 061803 (2005)
BF Belle Babar WA SM C7 = -C7SM
q2>(2m)2 4.11±1.1 5.6±2.0 4.5±1.0 4.4±0.7 8.8±0.7
1<q2<6GeV2 1.5±0.6 1.8±0.9 1.60±0.5 1.57±0.16 3.30±0.25
C7SM C7 = -C7
SM
C10NP C10
NP
C9NP
MXsq2
Branching Fraction of BK(*) ll
K+, Ks or K*(K+-, Ks+, K+0) + e+e- or +-
Mll>0.14GeV
A ratio of BF of K(*) to K(*)ee is sensitive to neutral heavy Higgs in 2HDM with large tan. In the SM, the ratio is 1.00 and ~0.75 for Kll and K*ll
250/fb data
Prediction by Ali et al.
Y. Wang and D. Atwood PRD68 (2003) 094016
G.Hiller and F.Krueger PRD 69 (2004) 074020
First look at AFB in K*ll
Sign of C7C10 can be determined from Forward-Backward Asymmetry in K*ll.
Raw AFB in each q2 region is extracted from Mbc fit. Kll has no asymmetry, so it is a good control sample. Curves show theoretical distributions including expe
rimental efficiency effect (not fitted lines! ). Both curves are in agreement with data, so far.
AFB K* l l
Ali et al. Phys.Rev. D61 (2000) 074024
SM
7 7eff eff
SMC Cq2
Summary
Many results for BF are consistent with the SM Precision of BF(bs) is 15% level.
Negative A7 solution is consistent with the SM A7 value
Upper limit on B(B()) is just above the predictions Constrain |Vtd/Vts|
Improved measurement of inclusive BXsll decay Sign of C7 flipped case with SM C9 and C10 values is unlikely
stringent limits on C9 and C10
Many measurements of Ratio Precisions of 0+ (BK* ) are 5% level
Towards sign of (C6/C7).
Time dep. CPV in BKs0 is measured for the first time Search for right handed component in C7
First look at Forward-Backward Asymmetry in BK*ll Will be used for measurement of A9 and A10
New results will be presented at Lepton Photon 05. Stay tuned
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