Statistical Methods for Data Analysis the Bayesian approach Luca Lista INFN Napoli.
L.Lista INFN Sezione di Napoli
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Transcript of L.Lista INFN Sezione di Napoli
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L.Lista INFN Sezione di Napoli
Rare and Hadronic B decaysRare and Hadronic B decays in B in BAABBARAR
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OutlineOutline
• Charmonium decays Inclusive Exclusive J/ K* angular analysis
• Open Charm• 2-body hadronic decays• quasi 2-body decays• Radiative penguin
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Inclusive CharmoniumInclusive Charmonium Decays Decays
Lepton identification • B-counting:
• Correct by (4S)
• 1.6% sys. Error
• 22,700,000 BB events
• Bremstrahlung-recovery for electrons• Background rejection: At least 3 tracks, Etot > 4.5 GeV Ratio of 2nd to 0th Fox-Wolfram moment R2 < 0.5
off
offMH
HMS N
NNNN )4(
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Inclusive Charmonium: J/Inclusive Charmonium: J/
• Inclusive branching ratio: Br(BJ/X) = (1.0440.013 0.028) 10-2
Br(BJ/X dir.) = (0.7890.010 0.034) 10-2
• J/ momentum distribution measured Y(4S) system = B system 250 MeV
• Polarization -0.4240.023 (-1 = longitudinal)• Signal from continuum subtracted ( …)
p*J/ < 2 GeV/c
J/ ll, l= e,
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• First observation of J/ production in continuum Rejection of BB (p*>2 GeV/c) Rejection of ISR (Ntracks, Etot, R2)
• Angular distribution: 1+A cos2*
• A (all E*) = 0.250.19 • A (p*>3.5 GeV) = 0.620.39
Color singles: A –0.8, 2.8 pb NDQCD (c.o): 0.6<A<1.0, 0.8 pb
J/J/ production in continuum production in continuum•
mode resonance p* cut (GeV/c) yield
on >287952ee on >279962 off -15625ee off -12126
Not a B decay, but a new BaBar result…
.).%90(103.4
21.021.052.2
4/)4(
/
LCB
pb
XJS
XJee
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Inclusive Charmonium: Inclusive Charmonium: (2S)(2S)
p* < 1.6 GeV/c
(2S) ll, J/
• Br( B (2S) X ) = (0.2750.020 0.029) 10-
2
(2S) ll branching ratio
• Assuming PDG values for (2S) J/
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Inclusive Charmonium: Inclusive Charmonium: cc
• Br(B c1 X) = (0.378 0.034 0.026)10-2
• Br(B c1 X dir.) = (0.353 0.034 0.024)10-2
• Br(B c2 X) = (0.137 0.058 0.012)10-2
< 0.2110-2 @ 90% C.L.
c2 (?)c2 (?)
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Exclusive decaysExclusive decays
• Several CP channels sin2
• Direct CP asymmetry
• Kinematics selection: Energy substituted mass
• Independent on particle mass hypotheses
Energy difference in the center of mass
Example: BD0
2,4 cmBES p
sm
2
sEE B mES (GeV/c2)
E (
GeV
)
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BBJ/J/KK00SS
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BBJ/J/KK00LL
• KL reconstructed as neutral deposit in the IFR or E.M. Calorimeter
• 1.4 < p*J/ < 2.0 GeV/c
• No momentum measurement• E is measured
assuming the mB mass constraint
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Selected channelsSelected channels
First observation
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Branching rations resultsBranching rations results
Mode Br (10-4)
B0J/0 0.20.060.03
B0J/K*0 12.40.50.8
B+J/K* 13.70.91.1
B+J/K 10.00.30.5
B0J/KKL 6.80.80.8
B0J/KKS00 9.61.50.7
B0J/KKS+ 8.30.50.6
B0c1K* 4.81.50.9
B+c1K+ 5.11.41.3
B+(2S)K+ 6.10.50.8
B0(2S)K0 6.51.01.1
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BaBar compared to PDG 2000BaBar compared to PDG 2000
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J/J/++ / J/ / J/KK++
• Cabibbo and color suppressed tree diagram possible CP asymmetry from penguin contribution
• Unbinned maximum likelihood fit based on kinematical variables:
• Br(B+J/K)/(B+J/) =(3.910.78 0.19)10-2
0 2 4 6 8 10
Br(B+ to JpsiPi+) / Br(B+ to Jpsi K+)
CLEO
CDF
PDG
BaBar
( 5.2 2.4 ) %
( 5.0 0.1 ) %
+1.91.7
( 5.1 1.4 ) %
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J/J/ K* angular analysis K* angular analysis
Channels with 0
Channels without 0
• f (costr, cosK*, tr) = f1 |A0|2 + f2 |A|||2 + f3|A|2
f4 Im(A||* A) + f5 Re (A0* A||) + f6 Im (A0* A)
J/ rest frameK* decay plane
|A|2 + |A|||2 + |A0|2 = 1
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J/J/ K* angular analysis K* angular analysis
|A|2 = 0.1600.032 0.014 CP odd, P wave
|A|||2 = 0.2430.034 0.017 CP even, S+D wave
|A0|2 = 0.5970.028 0.024 CP even, S+D wave
= arg(A/A0)=0.170.16 0.07
|| = arg(A|| /A0)=2.500.20 0.08
CP asymmetry dilution factor: D = 1 – 2 |A|2 = 0.680.10
(a) Raw measurement(b) Acceptance correction(c) “ “ + mES fit(d) “ “ + (Self) Feed Across
Indication of FSI
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BBD*D*, D*, D*
• May exhibit small CP asymmetries • Potential for sin(2+) and
• Reconstruct the decay chains:
• B reconstruction efficiencies estimated with MC
*0 DB
0D
K
0D
K
*0 DB0
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Br(BD*+) = (2.9 ± 0.3 ± 0.3 ) 10-3
PDG: (2.76 ± 0.21) 10-3
BBD*D*
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Br(BD*+) = (11.2 ± 1.1 ± 2.5 ) 10- 3
PDG: (6.8 ± 3.4) 10-3
BBD*D*
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B B D* D*++D*D*
• Independent measurement of sin2• D*D0, D0 D0K, K, K, KS
D K, KS, KK
• B decays with two 0 are not used High background, low branching fraction
• Many possible combinations in the same event. Chosen the one which minimizes:
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B B D* D*++D*D*
Br(BD*+D*-) = (8.0 1.6 1.2)10-4
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B B D*D D*D((**))KK
• bccs transition• D*+ D0+; • D*0 D00
• D*0 D0• D0 K-+, • D0 K-+0 • D0 K-+-+; • D+ K-++;
• Br(B D*D0K) = (0.280.070.05)10-2
• Br(B D*D*K) = (0.680.170.17)10-2
• Br(B D*D*K) = (0.340.160.11)10-2
First observation of non-charmonium color suppressed mode
B0 (all modes)NS = 18021
B+ (all modes)NS = 11715
B D*D*K
NS = 8.23.5
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Charmless Hadronic DecaysCharmless Hadronic Decays
• Physics motivations
b u
d(s)Vub
Vud(s)
B0 { }
} (K)
d d
u
bB0 {
d
u
d(s)
}
} (K)
d
u
t
W
W
Vtb
Vtd(s)
Cabibbo suppressed
Penguin diagram
• Significant penguin contribution
• Direct CP violation studies
• Measurement of from time-dependent asymmetry + isospin analysis
• Possible field for new physics…
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Identifying K and Identifying K and
• Particle identification in the DIRC
D*+D0, D0K-+ control sample
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Background RejectionBackground Rejection
• Continuum events rejection Fisher discriminator on event shape Thrust axis (B vs rest of event)
• Background control samples E sidebands Off-resonance data D*+D0, D0K+ control sample
signal
D0+
on reson. mES<5.26
background
background
signal
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Two Body Charged ModesTwo Body Charged Modes
• Bhh
K
KK
Mode Yeld, significance
Branching ratio
K 16917+12-17, 15.8
(16.71.6+1.2-1.7)10–
6
41107, 4.7(4.11.00.7)10–6
KK 8.2+7.8–6.43.3, 1.3
<2.510–6 (90%C.L.)
UML Fit results
Cut based selection
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Two Body Charged + Neutral ModesTwo Body Charged + Neutral Modes
• B0h0+
0K+Mode Yeld, significance
Branching ratio
37+15-13, 3.4
(5.1+2.0-1.8 0.8)10–6
K 75+14-13, 8.0
(10.8+2.1-1.9
+1.0-1.2 )10–6
UML Fit results
Cut based projections
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BBKK00hh++,, KK0000
K0+
K0K+
K00Cut based projections
Mode Yield, significance
Branching ratio
K0 59+11-10, 9.8
(18.2+3.3-3.0
+1.6-2.0)10–6
K0K 0 (< 8), 0<2.610–6 (90%C.L.)
K00 17.9+6.8-5.8, 4.5
(8.2+3.1-2.7
+1.1-1.2)10–6
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Charge AsymmetriesCharge Asymmetries
• KA = - 0.190.100.03 [ -0.35, -0.03 ], 90%C.L.
• KA = 0.000.180.04 [ -0.30, +0.30 ], 90%C.L.
• KA = - 0.210.180.03 [ -0.51, +0.09 ], 90%C.L.
• All asymmetries compatible with 0 within current errors
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B+h+ < 24 10-6 ( 90% C.L. )
B0K0 < 14 10-6
B+K+ ( 62 18 8 ) 10-6
B0K0 < 112 10-6
B0K*0 < 28 10-6
B+0K+ < 39 10-6
B+0+ < 39 10-6
B+K+< 54 10-6
B++< 22 10-6
B0( 49 13+6-5 ) 10-6
Quasi 2-body and 3-body decaysQuasi 2-body and 3-body decays
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BBK, BK, BK* K*
• Penguin dominated • Measure of sin2
B+K+ = (7.7+1.6-1.40.8) 10-6
B0 K0 = (8.1+3.1-2.50.8) 10-6
B+ K*+ = (9.7+4.2-3.41.7) 10-6
B0 K*0 = (8.6+2.8-2.41.1) 10-6
B0 < 1.4 10-6 (90% C.L.)
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B B K* K*
Signal:
B0 K*0, K*0 K+-
Backgrounds:
e+e- qq
e+e- qq X 0
• Sensitive to top quark couplings CKM matrix elements
Vtd,Vts
• Sensitive to New Physics SUSY, Charged Higgs
• No CP asymmetry in the Standard Model Possible sources
beyond SM
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B B K* K*: yield and branching ratio: yield and branching ratio
• Nsignal = 139.2 13.1 events• Br(B0 K*0) = (4.39 0.41) 10-5
• Br(B K+e+e-) < 12.8 10-6
• Br(B K++-) < 8.3 10-6
• Br(B K*0e+e-) < 24.7 10-6
• Br(B K*0+-) < 25.7 10-6 (90% C.L.)
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B B K* K*: CP asymmetry: CP asymmetry
K*0
K*0
-
• K*0 K
• N(B0) = 72.1 9.4 events• N(B0) = 67.2 9.1 events
• ACP = -0.035 0.09
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bbss, B , B
• Semi-exclusive study Sum of exclusive modes
K+n(n=1,2,3)
• B(B0) < 1.94 x 10-6 90% C.L.• PDG: B(B0 ) < 3.9 x 10-5 90% C.L. (from L3)
mES for 0.6 <mhad < 2.0 GeV
668 53 events
PRELIMINARY
PRELIMINARY
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ConclusionsConclusions
• Many branching ratios have been measured in BaBar
• Some are newly observed signals• Potential for more CP violation studies• More statistics will permit to measure CP
asymmetries
• Stay tuned!