Roma 19/12/03 Fabio Bellini 1
Radiative and ElectroweakPenguin B-Decays
with the Babar Detector
Fabio BelliniUniversità di Roma “La Sapienza” & INFN Roma I
Roma 19/12/03 Fabio Bellini 2
2XWOLQH
¾Radiative decays:E��!�Vγ and E��!�Gγ�%��!�;Vγ�%�. �����γ�%�ω�ρ�γ
¾Electroweak decays:E��!�VO�O�
�%��!�.O�O�
�%��!�. O�O�
�%��!�;VO�O�
¾Challenging modes with neutrino and/or helicity suppression:�%��!�O�O�
�%��!�.νν
Roma 19/12/03 Fabio Bellini 3
,QWURGXFWLRQ
¾Rare processes involvingFlavour Changing Neutral Current
=> Breaking Flavour Symmetryof the SM
•No tree-levelcontribution within SM
•Dominated by short-distancedynamics
precise test of flavour dynamics sensitivity to New Physics
Roma 19/12/03 Fabio Bellini 4,VLGRUL
6HQVLWLYLW\�WR�1HZ�3K\VLFV�
G.Isidori
Λ: New Phisycs Scale
Roma 19/12/03 Fabio Bellini 5
E��!�Vγ proceeds via flavour changing neutral current
leading order: penguin diagram
7effc
¾E��!�Vγ�%U(E�!Vγ) ≈ ����•���� �QRW�VR�UDUH�DFWXDOO\�•Direct Charge Asymmetry ACP very small in SM: ≈ 0.6%•New Physics could change Br and enhanceACP through heavy particles(H,,χχ ) entering theloop
¾Tool for B meson dynamics:•Photon Energy spectrum handle forVub
E�!Vγ
((χχ))
Roma 19/12/03 Fabio Bellini 6
E�!VO�O�
E��!�VO�O� proceeds via flavour changing neutral current
SHQJXLQ
�
ER[
%U�E�!VO�O����∼ αem⋅%U�E�!Vγ� ≈ ���� ���
¾E��!�VO�O�
•Z penguin & box diagrams contribute at leading order. •More dimensions to explore: Minv(l+l-)=q2 & lepton forward-backward asymmetry AFB
=> Ideal testing ground for SM and extensions(2HDM, MSSM, GUT, …?)
Roma 19/12/03 Fabio Bellini 7
E�!GO�O� �E�!GγE��!�GO�O� & E��!�Gγ suppressed by |Vtd/ Vts|2
SHQJXLQ
�
ER[
d d
Vtd VtdVtbVtb
�%5�E�!Gγ� ≈���� : Not seen yet.•Annihilation diagram contributesto %+ �!�ρ+γ
E��!�GO�O�
d
Vtb Vtd
E��!�Gγ
Roma 19/12/03 Fabio Bellini 8
HHII
∼ ∑��
L � &L�µ�OOL�µ�
/RZ�(QHUJ\�(II��+DPLOWRQLDQ
2: matrix element=>long distance&� Wilson coeffcient=>short distanceµ: factorization scale
Operator Product Expansion: separation of long & short distance contributions
• C: encodes information on heavy degrees of freedom(t, W, Z)=> sensitive to NPNLO,NNLO calculations
• O: Exclusive decays => hadronic form factors=>large uncertanties=> σ(Br) ~ 30%, $)% �$&3 more reliable σ~15%
Inclusive decays=> HQE+duality (Γ(B→Xs γ)~Γ(b→s γ))=> non-perturbative contributions under control=> σ(Br) ~ 10%
Roma 19/12/03 Fabio Bellini 9
/RZ�(QHUJ\�(II��+DPLOWRQLDQ
¾Γ�E�!Vγ� ∼ _9 WV9WE_� _&�_
� ����PE�F FRUUHFWLRQ�
•Interesting observables� %U� $&3� γ VSHFWUXP•NLO calculation: %U(%�!;Vγ) =(����±����� •����
(Gambino & Misiak Nucl.Phys. B 611, 2001)
¾Γ�E�!VO�O���GV ∼ _9
WV9WE_� 2�T��P�
E �_&�_��_&
�_��_&
��_��&
� 5H�&
�� ����PE�F
FRUU��•Interesting observables� %U� $)%� GΓ�GT� GLVWULEXWLRQ•NNLO calculation: (large non perturbative effect in cc resonance region)
%U(%�!;VO�O�): (����±����� •���� ��T� �� *H9
(����±����� •���� T� !���� *H9�
�Ghinculov, Hurth, Isidori & Yao, 2003)
Roma 19/12/03 Fabio Bellini 10
$QDO\VLV�WHFKQLTXHV¾Exclusive:e,K, µ,γ,π PID and mass and energy constraints: mES, ∆Etheories are not so reliable
¾Inclusive•Semi-Inclusive(e.g. B -> Xsγ with X s =K+n(π))large model dependence•Fully Inclusive(e.g. the γ only in B -> Xsγ)very huge background
∆E =E*B -E*beam
( )22BbeamES PEm −=
e+e- →Υ(4S) → BB
Roma 19/12/03 Fabio Bellini 11
11
Exploit the B-decay isotropy vs the “jet-like” topology of qq eventsUse B properties and shape variables: decay angle, ∆z, cosθThrust, energy flow,ThrustCuts on combination of variables (Fisher Discriminant or Neural Network). :
&RQWLQXXP�EDFNJURXQG�UHMHFWLRQ
NN output:Κ∗γ analysis
Roma 19/12/03 Fabio Bellini 12
12
VE
γE
;V
%γ
% �! ;Vγ %%
TT
%�!;Vγmonochromatic spectrum (Eγ~mb/2) smearead by b-s interaction & confinement =>Fermi motion
mb 4.65mb 4.80mb 4.95
Huge bkgd=> (Á FXW
ODUJH WKHR� HUURU
Eγ(GeV)
Roma 19/12/03 Fabio Bellini 13
Br(B�Xsγ) = (3.88 ± 0.36 (stat) ± 0.37 (syst)+0.43 (model))·10-4
)XOO\�,QFOXVLYH�%�;Vγ
-0.23
13
Data
BB expected events
Integrated to obtainBranching Fraction
Preliminary High energy photon: Emc shower profile consistent withγ hyp., π0 and η veto , lepton tag on other B
Signal region: Εγ [2.1; 2.7] GeV
Dominant Stat error due to ~6fb-1 off-resonance used for continuum subtraction
Dominant Syst error from BB subtraction :(π0 and η from B decays can fake γ)
Β��Xdγ events subtracted using theory prediction: (4.0±1.6)%
hep-ex/0207076
54.4 fb-1
Roma 19/12/03 Fabio Bellini 14
,QFOXVLYH�%�;Vγ ZLWK�VLQJOH�%�EHDP
ee--DD**
ππ
ee++
BBrecoreco
BBrecoilrecoil
XsXs
γγ
Novel technique: reconstruct one B in a fully hadronic decay
¾Advantages:• Breco (recoil) kinematicswell known
⇒Eγ studied in theB rest frame⇒better resolutionon Eγ(no B boost smearing)
• mES distribution on Breco used for a side-band subtraction⇒ no need to use off-resonancedata for continuum bkgd
•Charge & flavour separation•Clean environment =>Eγ lower cut: 1.9 GeV
• Reconstruction efficiency ~ 2.3•10-3
Only B-factoriescould explore this technique
Roma 19/12/03 Fabio Bellini 15
sigtag
alltag
selBreco
sig
S N
NXBBr
εε
εγ ⋅
⋅=→ )(
,QFOXVLYH�%�;Vγ ZLWK�VLQJOH�%�EHDP•Analysis performed in B rest frame
•Photon selection like Fully Incl. analysis +Fisher for continuum suppressionρ veto for BB background
•Signal extracted from a χ2 fit to the Eγ spectrum-bkgd and signalshapetaken from MC-bkgd Normalization fixed in a side-bandregion: E*<1.9 GeV & extrapolated in signal region:
Very Low model dependence ~5%•More statistics =>precision measurement=>Eγshape & ACP
Br(B�Xsγ) = (3.82 ± 0.98 (stat) ± 0.65 (syst)+0.23-0.20 (model))·10-4
Εγ [1.9; 2.7] GeV
81.9 fb-1
Preliminary
Roma 19/12/03 Fabio Bellini 16
&RPELQDWRULDO�ENJG�VXEWUDFWLRQ
•Samples divided in bins of E.•mES distribution of the fully reconstructed B is fitted in each binto properly subtract combinatorial bkgd
carichi e nuetri
MESdistribution for MC bkgd sample
Roma 19/12/03 Fabio Bellini 17
%�;Vγ EUDQFKLQJ IUDFWLRQV
%U�%�;Vγ )∗10−4
no deviations from SM so far:consraints on new physics
Br in particular MSSM scenario Carena et Al. PLB499, 411
BaBar Breco SM prediction: Br(3.73±.0.30)*10-4Gambino &Misiak Nucl.Phys. B 611
No deviations so far: constraints on NP“The most effective NP Killer” G. Isidori
tanβ
Roma 19/12/03 Fabio Bellini 18
%��!�. γ• K ∗+
�Κ+π0 , ΚS0π+ , Κ∗0
�Κ+π−, ΚS0π0
• isolated high energy γ: 1.5 < E*γ < 4.25 GeV
• π0/η veto,
• π,K PID
• K*(892) reconstructed in 4 final states:
0.8 < M(Kπ) < 1 GeV/c2
• BKG suppression against e+e- -> qq(g) ->NN
• Signal extraction : 2-D UML fit to ∆E and mES
E (GeV)∆-0.3 -0.2 -0.1 0 0.1 0.2 0.3
Even
ts /
( 0.0
12 G
eV )
0
10
20
30
40
50
E (GeV)∆-0.3 -0.2 -0.1 0 0.1 0.2 0.3
Even
ts /
( 0.0
12 G
eV )
0
10
20
30
40
50
E"∆A RooPlot of "
(GeV)ESm5.2 5.21 5.22 5.23 5.24 5.25 5.26 5.27 5.28 5.29 5.3
Even
ts /
( 0.0
02 G
eV )
0
10
20
30
40
50
60
70
80
90
(GeV)ESm5.2 5.21 5.22 5.23 5.24 5.25 5.26 5.27 5.28 5.29 5.3
Even
ts /
( 0.0
02 G
eV )
0
10
20
30
40
50
60
70
80
90
"ESA RooPlot of "m
∆∆( ( PP(6(6
––SignalSignal––Generic B Generic B BkgBkg..––Continuum Continuum BkgBkg
.. � �→→..��ππ��
Br ( B0 -> K*0 γ) =(39.2 ± 2.0 ± 2.2) (⋅10-6)
Br( B+ -> K*+ γ ) =(38.7 ± 2.8 ± 2.4) (⋅10-6)
81.9 fb-1
Preliminary
K ∗+� ΚS
0π+
Roma 19/12/03 Fabio Bellini 19
$,6�%��!�. γ �
,QYHVWLJDWH�,VRVSLQ DV\PPHWU\�EHWZHHQ�%� DQG�%��
UHODWHG�WR VLJQ�&��&��
∆�� �������± ����± ��������%D%DU������IE���
∆�� �������± ����± ��������%HOOH�����IE����)3&3��
60�SUHGLFWV��∆0+ = (8.0 +2.1 −3.2) %
∆�� %5�%��!. �γ��² %5�%��!. �γ�
%5�%��!. �γ����%5�%��!. �γ�τ%�
τ%�
τ%�τ%�
τ%�τ%� ����� ± ����� >3'*����@
Kagan and NeubertPhys. Lett. B539 227 (2002)
81.9 fb-1
Preliminary
Roma 19/12/03 Fabio Bellini 20
%D%DU6WDWXV�RI�E�!Vγ
%HOOH
Channel BR (⋅10-6) ∫Ldt
===================================================
B -> Xs γ 388 ± 36 ± 37 +43/-23 54.6 fb-1
B0 -> K*0 γ 39.2± 2.0± 2.2 81.9 fb-1
B+ -> K*+ γ 38.7± 2.8± 2.4 81.9 fb-1
B0 -> K*02(1430) γ 12.2 ± 2.5 ± 1.1 81.9 fb-1
B+ -> K*+2(1430) γ 14.4 ± 4.0 ± 1.3 81.9 fb-1
===================================================
B -> Xs γ 336 ± 53 ± 42 +50/-54 6 fb-1
B0 -> K*0 γ 40.9 ± 2.1 ± 1.9 78 fb-1
B+ -> K*+ γ 44.0 ± 3.3 ± 2.4 78 fb-1
B0 -> K*2(1430) γ 13 ± 5 ± 1 29 fb-1
B+ -> φ K + γ 3.4 ± 0.9 ± 0.4 90 fb-1
B+ -> K+π+π− γ 24 ± 5 +4/-2 29 fb-1
Roma 19/12/03 Fabio Bellini 21
% �! . ����� γ �������
% �! . ������� γ ����
% �! . π γ ����
% �! . ρ γ ����
% �! . φ γ ����
� .πQγ �Q! ��� %DU\RQV���γ �≤����� 0RGH�ZLWK�UHVRQDQFHV�H�J��η��η·
� ...πQγ �≠.φγ�� «
6WDWXV�RI�E�!Vγ
������RI�E�!Vγhas been measured exclusively
Roma 19/12/03 Fabio Bellini 22
'LUHFW�&3�YLRODWLRQ�$&3
•Same (Excl. & Semi-Incl Br) analysis: mixed-flavour modes discarded
SM: small ACP (~ 0.6%) , sensitive to non-SM extra contributionsthat might cause CP-violating charge asymmetries as high as 20%
→+→
→−→=
γγ
γγ
KBNKBN
KBNKBNACP **
**
Babar (81.9 fb-1 ) Belle (78 fb-1 ) FCPP03
ACP( B0 -> K*0 γ) -0.069 ± 0.046 ± 0.011 -0.029± 0.054 ± 0.011
ACP ( B+ -> K*+ γ ) 0.074 ± 0.059 ± 0.006 0.054 ± 0.076 ± 0.014
Preliminary
Babar (113 fb-1 ) Belle (140 fb-1 )
ACP 0.025 ± 0.050± 0.015 -0.004± 0.051 ± 0.038
K* γ
Sem-Incl
Roma 19/12/03 Fabio Bellini 23
B�ρ/ω γ
23
B0��ρ0γ, ρ0
��π+π-
B±��ρ±γ, ρ±
��π+π0
B0��ωγ, ω��π+π-π0
78 fb-1
¾Low Br ~1 x 10-6
¾Reco modes:ρ0��π+π-,, ρ + ��π+π0, , ω ��π+ π- π0,
¾520(760)<Mππ(π). <1020(805) MeV
¾Lar ge B background from K * γ ,2% kaon fake at 80% pion efficiency
¾ A 2(3)-UML fit is used to extract signal yields: ∆E , mES, (mρ)
No Evidence of signal, upper limits are set:
B(B0��ρ0γ) < 1.2·10-6 @ 90%CL
B(B±��ρ±γ) < 2.1·10-6 @ 90% CL
B(B0��ωγ) < 1.0·10-6 @ 90% CL
(hep-ex/0306038 submitted to PRL)
Roma 19/12/03 Fabio Bellini 24
B�ρ/ω γ Upper /LPLWV @ 90% CLBaBar BELLE CLEO Theory
(Ali&Parkomenko)
B(B0��ρ0γ) < 1.2·10-6 < 2.6·10-6 < 17·10-6 = (0.49±0.18)·10-6
B(B±��ρ±γ) < 2.1·10-6 < 2.7·10-6 < 13·10-6 = (0.90±0.34)·10-6
B(B0��ωγ) < 1.0·10-6 < 4.4·10-6 < 9.2·10-6 = (0.49±0.18)·10-6
24
Preliminary Preliminary
Assuming (isospin symmetry)A(B��ργ) = A(B±��ρ±γ) = sqrt(2) x (B0
�� ρ 0γ) Combined the upper limit obtainedBr(B�� ρ γ ) < 1.9 10-6
Using (Ali & Parkhomenko Eur. Phys. J. C.23, 89 (2002))Br(B�� ρ γ )/Br(B��K * γ ) =
|Vtd/Vts|2 z2 |1+∆R| (1-mr2/MB
2)3/(1-mK*2/MB
2)3
with z=0.76±0.10, ∆R=0.0±0.2
|Vtd|/|Vts|<0.34 @ 90% CL
-1 -0 .5 0 0 .5 10
0 .2
0 .4
0 .6
0 .8
1
Μ
ρ
η
ksψa
∆MB d
Β∆
s
VubVc b
εkR
(
/ K
)∗
ργγ
ksψa
Roma 19/12/03 Fabio Bellini 25
(OHFWURZHDN�GHFD\V�E�!VO�O�
Roma 19/12/03 Fabio Bellini 26
E�!VO�O��SUHGLFWLRQV
q2
AF
B
¾BF: αεµ⋅%5�E�!Vγ� ≈ ���� but much less bkgd than E�!Vγ¾interplay between Z and γ => q2 dependence
• Forward-backward lepton asymmetry AFB(q2) sensitive to non SM effecteven if rates agree(E�!V�OO�γ)
•AFB(q2) needed in addition to Br to disentangle C7 , C9 , C10 contributions
q2SM nonres
*B K µ µ+ −→ J/ψΚ
ψ(2S)K
dΓΓ/d
q2
SUSY models
Ali et al. ‘01
Roma 19/12/03 Fabio Bellini 27
%�Æ .� � O� O�
Reconstruct K +, KsÆÆ π +π-, K*0ÆÆ K + π−, K *+ ÆÆ Ks π+
•Tight lepton ID for: e+e- with p(e) > 0.5 GeV/c,brems recoveryµ+ µ - with p(µ ) > 1.0 GeV/c
•Photon conversionsare vetoed M(ll)>0.2 GeV•Continuum suppressed by Fisher: event shape variables•BB background suppressed by Emiss, cosθB , vertexing•J/ψ and ψ’ veto•Background from lepton miss-identification B ÆÆ h+h- K (*)
vetoed if M(h-K (*)) consistent with D mass
J/ψψ veto ψψ’ veto
Mll [Gev/c2] Mll [Gev/c2]
∆E [G
eV]
∆E [G
eV]
113 fb-1
Roma 19/12/03 Fabio Bellini 28
Signal yield:2-D UML fit tomES & ∆E
%�Æ .�� � O� O�
Br= (6.5 +1.4-1.3 ± 0.4 ) ⋅10-7
Submitted to PRL, hepSubmitted to PRL, hep--ex/0308042ex/0308042
8.4σ
113 fb-1
Signal yield:3-D UML fit tomES & ∆E, mKπ
Br= (8.8 +3.3-2.9 ± 1.0 ) 10-7
K*ee = 1.33 K*µµ assumed to compensate q2 =0 pole
3.3σ
Roma 19/12/03 Fabio Bellini 29
4.6
2.2
4.0
significance(σ)
41.4 ± 10.3Sum
12.4 ± 6.2Xs µ+ µ -
29.0 ± 8.3Xs e+e-
yield(± stat)Mode
Br(B → Xs e+e−) = (6.6 ± 1.9 ± 1.91.6) 10−6
Br(B → Xs µ+µ−) = (5.7 ± 2.8 ± 1.71.4) 10−6
Br(B → Xs l+l−) = (6.3 ± 1.6 ± 1.81.5) 10−6
%�Æ ;6 O� O� 5HVXOWV�%DEDU�
•unbinned maximum LH fit to mES
•signal is seen in electron mode
81.9 fb-1
Preliminary
Reconstruct XS as: (K+,Ks) +0-2 π (up to 1 π ο ) (75% of signal)
Roma 19/12/03 Fabio Bellini 30
0
10
20
30
40(a) Xse
+e- (b) Xsµ+µ-
5.2 5.22 5.24 5.26 5.280
20
40
60
(c) Xsl+l-
5.2 5.22 5.24 5.26 5.28
(d) Xse+µ- + c.c.
Mbc (GeV/c2)
Entri
es /
(2.5
MeV
/c2 )
• Published: PRL 90, 2180• signal is seen in both electron
and muonmode • XS :(82% of signal)
5.460.1 ± 14 sum
4.737.3 ±9.7 XS µ µ
3.425.5 ± 11.2 XS e e
significance(σ)yield (± stat)
%�Æ ;6 O� O� 5HVXOWV��%HOOH�
Br(B → Xs e+e−) = (5.0 ± 2.3 ± 1.31.1) 10−6
Br(B → Xs µ+µ−) = (7.9 ± 2.1 ± 2.11.5) 10−6
Br(B → Xs l+l−) = (6.1 ± 1.4 ± 1.41.1) 10−6
60 fb-1
Roma 19/12/03 Fabio Bellini 31
0OO DQG�0;V LQ�%�Æ ;6 O� O�
0�1DNDR /3����
•from a bin by bin fi tto M ES
•no deviation in M(l-l+)•more data => measure AFB
Roma 19/12/03 Fabio Bellini 32
• C9 and C10 can be constrained from Br(BÆÆXs l+ l-)– Ci
NP = Ci - CiSM
– (0,0) if the SM holds. Dots show Extended-MFV model– Strong constraint on C9 and C10 but sgn(C7) is not determined
yet.
C10
NP
C9NPC9
NP
C10
NP
&RQVWUDLQW�RQ�&� DQG�&��
0�1DNDR /3����
Roma 19/12/03 Fabio Bellini 33
%D%DU
%HOOH
6WDWXV�RI�E �!�V�O�O�
&KDQQHO %U �⋅����� ∫LGW
% �! ;VO�O� �� ± �� ������� �� IE��
% �! .O�O� ��� ��������� ± ��� ��� IE��
% �! . O�O� ��� ��������� ± ��� ��� IE��
����������������������������������
% �! ;VO�O� �� ± �� ������� �� IE��
% �! .O�O� ��� ��������� ± ��� ± ��� ��� IE��
% �! . O�O� ���� ��������� ± ��� ± ��� ��� IE��
Br(% �! . O�O� ) = (��� ± ���� ⋅���� �ODUJH HUURU GXH WR IRUP IDFWRUV�
Br(% �! . O�O� ) = (���� ± ���� ⋅���� $OL HW $O� ���� 11/2
Br(% �! ;VO�O� ) = (�� ± �� ⋅���� ��σ RII� HUURU VWLOO ODUJH�
Roma 19/12/03 Fabio Bellini 34
'HFD\V�ZLWK�neutrino and/or helicity suppression
Roma 19/12/03 Fabio Bellini 35
Hadronic tag: %��!'� �;KDG Semileptonic Tag: %��!'�Oν(π,γ)
%� Æ .νν •Theoretically cleaner than B -> K*ll because of no cc resonance effect•Only one K in the final state( require p*>1.25GeV)• 2 umeasured ν’s ⇒ Reconstruct one B& look for signal in the recoil side
Eextra
tagging efficiency:~2 · 10-3 tagging efficiency:~5·10-3
D0 =>K-π+, K-π+ π+ π-, K-π+ πo
Remaining neutral Energy (GeV)mES (GeV)
Roma 19/12/03 Fabio Bellini 36
80.7 fb-1 :Br < 1.05 x10-4 @ 90% CL
Combined limit @ 90% CL < 7.0 x 10Combined limit @ 90% CL < 7.0 x 10--55 hephep--ex 0304020ex 0304020
50.7 fb-1: Br< 9.4x10-5 @ 90% CL
SM Expectation: (3.8 +1.2 -0.6) x 10-6 (Buchalla, Isidori,2000)
%� Æ .νν Semileptonic B tag
M(D
0 )-M
(D0
PD
G)
σM
(D)
Hadronic B tag
PP(6(6
signal box
side-band
mES (GeV)Remaining neutral Energy (GeV)
Roma 19/12/03 Fabio Bellini 37
!�)&1&��+HOLFLW\ VXSSUHVVHG���ERG\�GHFD\�LQ�60
�
%5�LQ�60� %�!τ+τ− ≈ ��⋅ ����
%�!µ+µ− ≈ �����
%�!H+H− ≈ � ⋅ �����
%�!Hµ IRUELGGHQ LQ 60� EXW SRVVLEOH LQ 686< RU /HSWR�4XDUN PRGHOV�
1RW REVHUYDEOH� EXW HQKDQFHPHQW E\ ��� RUGHUV RIPDJQLWXGH LQ �+'0 RU = PHGLDWHG )&1& PRGHOV�
%� Æ O��O�
Roma 19/12/03 Fabio Bellini 38
%� Æ O��O� �%DEDU��%HOOH�
[GeV]ES
m5.2 5.22 5.24 5.26 5.28 5.3
E [GeV]
∆
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
BABAR
Β e e+ −
[GeV]ES
m5.2 5.22 5.24 5.26 5.28 5.3
E [GeV]
∆
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
BABAR
Β µ µ+ −
[GeV]ES
m5.2 5.22 5.24 5.26 5.28 5.3
E [GeV]
∆
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
BABAR
Β e µ+ +−−
e+e- µ+µ− e+µ−
Both Belle(78 fb -1) and Babar (54.4 fb -1) observe no events
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
5.2 5.22 5.24 5.26 5.28 5.3
ee
Mbc(GeV/c2)
∆E(G
eV)
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
5.2 5.22 5.24 5.26 5.28 5.3
eµ
Mbc(GeV/c2)
∆E(G
eV)
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
5.2 5.22 5.24 5.26 5.28 5.3
µµ
Mbc(GeV/c2)
∆E(G
eV)
•Tight lepton ID•pmis and multiplicity cut•continumm bkgd=>event shape•bkgd:leptons in cc eventsπ−µ mis-id (µ- µ+ )2γ processes (e+e-& e+µ)-
•bkgd estimated on datasidebands & extrapolated in the signal mES box
Belle
Babar
Roma 19/12/03 Fabio Bellini 39
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Roma 19/12/03 Fabio Bellini 40
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500 fb-1 in 2006!
Roma 19/12/03 Fabio Bellini 41
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Roma 19/12/03 Fabio Bellini 42
DIRC (PID)144 quartz bars
11000 PMs
1.5 TsolenoidEMC
6580CsI(Tl) crystals
Drift Chamber40 stereo layers
Instrumented Flux Return
iron / RPCs (muon/ neutral hadrons)
Silicon Vertex Tracker5 layers, double sided
strips
e+ (3.1 GeV)e- (9 GeV)
SVT+DCH: σ(pT)/pT = 0.13 % × pT + 0.45 %, good dE/dxDIRC: K-π separation 4.2 σ @ 3.0 GeV/cÆ 2.5 σ @ 4.0 GeV/cEMC: σE/E = 2.3 %⋅E-1/4 ⊕ 1.8 %IFR: Good muon identification
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Roma 19/12/03 Fabio Bellini 43
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81.9 fb-1
•Similar selection of . γ•Bkgd non resonant decays & . ������ γ� cosθhel
UML fit to ∆E , mES, cosθH
5.8 σ for . �� γ4.1 σ for . �� γ
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Roma 19/12/03 Fabio Bellini 44
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Br ( B0 -> K2*0 γ)= ( 12.2 ± 2.5 ± 1.1)⋅10-6
Br ( B+ -> K2*+ γ ) = (14.4 ± 4.0 ± 1.3) ⋅10-6
Br ( B0 -> K2*0 γ)= (13 ± 5 ± 1) ⋅10-6 Belle (78 fb-1 ) PRL 89,2318
81.9 fb-1
Preliminary
Roma 19/12/03 Fabio Bellini 45
BaBar:M ll data comparisonwith SM predictions
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Belle:M ll data comparisonwith SM predictionsfrom bin by binfit to M es