Recent results on CP violation in B decays

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Recent results on CP violation in B decays

• Marcello A. GiorgiUniversità di Pisa and INFN
  Pisa
• presented at XXXII International Conference on
  High Energy PhysicsBeijing, ChinaAugust 16-22,
  2004

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Current luminosities and data samples
Total 244 286
fb-1 0.530 ab-1!!
22fb-1/month
17fb-1/month
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BABAR Detector
EMC 6580 CsI(Tl) crystals
e (3.1GeV)
1.5T solenoid
DIRC (PID) 144 quartz bars 11000 PMs
Drift Chamber 40 layers
e- (9GeV)
Silicon Vertex Tracker 5 layers, double sided
strips
Instrumented Flux Return iron / RPCs (muon /
neutral hadrons)
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CKM and unitarity conditions
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3 ways for CP violation
First mechanism observed historically in kaon
decays
1. CP violation in mixing
SM predicts
2. Direct CP violation in the decay
Two amplitudes A1 and A2 with a relative CP
violating phase f2 and a CP conserving phase d
CP violation and .
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First observation of Direct CPV in B decays
hep-ex/0408057, submitted to PRL
BABAR
BABAR
4.2s
Belle
Confirmation at ICHEP04
3.9s
Average
3.6s
Average
J. Wu, Y.Chao, CP-6
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3 ways for CP violation
3.Time dependent
Define CP Asymmetry as
Decaymixing
No oscillation
Net oscillation
For single amplitude
Amplitude ratio
CP parameter
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Measuring time-dependent CP asymmetries
Tagging performance Q 30.5
Dz
Start the Clock
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sin2b results from charmonium modes
Belle 2003
BABAR
Update for ICHEP04
Belle CONF-0436
BABAR PUB-04/038
M.Bruinsma, T. Higuchi, CP-3
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sin2ß, cos2ß and CKM constraints
BABAR
cos2b lt 0 ruled out at 87 CL by s- and p-wave
interference in angular analysis of B J/yK0
(KSp0)
cos2ß lt 0
cos2ß gt 0
M.Bruinsma, CP-3
CKM fit to indirect constraints overlaid with
sin2ßWA measurement
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Methods for extraction of g
GLW
Gronau-London-Wyler, 1991
Atwood-Dunietz-Soni, 2001
ADS
D0 Dalitz plot
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B- ? D()0Kp-K- decays ADS method
BABAR
Update for ICHEP04
Belle
BABAR CONF-04/013
G.Cavoto, A.Bozek, CP-4
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First look at B- ? D()0KSpp-K- sample by Belle
Belle 140 fb-1
New Winter 04
Visible asymmetry in Dalitz plots
hep-ex/0406067
A.Bozek, CP-4
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BABAR analysis of B- ? D()0KSpp-K-
68
90
New for ICHEP04
BABAR
g deg
g deg
No sensitivity to rB lt 0.1
Poor constraints on g as yet
BABAR CONF-04/043
G.Cavoto, CP-4
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sin2? from B ? ??, ??, ??
Interference of suppressed b ? u tree decay
with mixing
but penguin is sizeable!
B0 decay penguin
B0 mixing
B0 decay tree
Coefficients of time-dependent CP Asymmetry
With no penguins
With large penguins and P/T 0.3
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Results for sin2?eff from B ? ?? decays
BABAR Updated for ICHEP04
BABAR
Belle PRL 93 (2004) 021601
BABAR CONF-04/047, 04/035
Comparison
Caution averaging!
M.Cristinziani, CP-5
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Result for B ? p0p0
Updated for ICHEP04
BABAR CONF-04/035
Improved understanding of p0 efficiency
4.9s
6.0s
Consistent at 1.3s level
M.Cristinziani, CP-4 Y.Chao, CP-6
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Results for sin2?eff from B ? rr decays
Extraction of a similar to pp, but with advantage
of smaller Penguin pollution
BABAR
Moriond QCD04
C.Dallapiccola, CP-6
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Isospin Corrections for a
PRL 91 (2003) 171802
BABAR
Updated for ICHEP04
BABAR CONF-04/037
Compare with 35o for pp
Geometric limit on 2dapeng Grossman-Quinn bound
C.Dallapiccola, CP-6
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Basis for Dalitz plot analysis of B0 ? (rp)0
Quasi-two-body approach to Snyder-Quinn method
Phys.Rev. D 48, 2139 (1993)

• Extract a and strong phases using interference
  between amplitudes
• Amplitude A3p dominated by rp-, r-p, r0p0 and
  radial excitations
• Form time-dependent decay rate coefficients of
  cos(DmdDt) and sin(DmdDt) on this basis

r-p
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Results from Dalitz analysis of B0 ? (rp)0
Evidence for direct CP 2.9s
BABAR
Based on factorization SU(3) Gronau Zupan
BABAR CONF-04/038
hep-ex/0408003
M.Cristinziani, CP-5 A.Somov, CP-6
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Summary of constraints on a
BABAR Belle combined
Mirror solutions disfavored
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CKM constraints and sin2b and a measurements
CKM fit to indirect constraints overlaid with
sin2ßWA and a measurements
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Beyond the Standard Model?
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sin2b and..... and....
New phases from SUSY?
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BABAR results for B0 ? fK0
2004 227M BB pairs (2003 120M pairs)
2003 result
BABAR
Update for ICHEP04
-
BABAR-CONF 04/033
A.Hoecker, CP-4
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More BABAR results from b ? sss penguins
Update for ICHEP04
BABAR CONF-04/025
BABAR

• Independent sample with (KK-) mass outside f
  region
• CP content can be determined experimentally with
  an angular moment analysis through the helicity
  angle distribution

A.Hoecker, CP-4
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More BABAR results from b ? sss penguins
BABAR
CONF 04/040 CONF 04/019
BABAR
Updates for ICHEP04
A.Hoecker, CP-4
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Still another penguin mode B0 ? p0KS
Beam constraint
BABAR technique from 2003
Updated for ICHEP04
BABAR CONF-04/030
BABAR
sPlots Pivk, Le Diberder, physics/0402083
Belle
BABAR
A.Hoecker, CP-4 C.F. Chen, CP-3
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Results on sin2b from s-penguin modes
All new!
All new!
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Projections for Penguin Modes
f0KS KSp0 jKS hKS KKKS
Luminosity expectations
2004240 fb-1 20091.5 ab-1
Kg
Similar projections for Belle as well
5s discovery region if non-SM physics is 20
effect
2009
2004
Projections are statistical errors only but
systematic errors at few percent level
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Conclusions and outlook

• Success of B Factory experiments BaBar and Belle
  of b?ccs (new sin2b value from charmonium 0.726
  037)
• Good agreement between BaBar and Belle results on
  b?sss penguin, but both experiments still show
  discrepancies (2.7 and 2.4s) with charmonium!!
• Observation by BaBar of direct CP violation in
  charmless B decays confirmed by Belle (average
  value )
• Quantitative measurements of a (f2) are emerging
  (new value )
• Constraints on g (f3) are still poor with present
  statistics (low values for rB).

• A statistical increase on these modes in the next
  few years could well provide initial evidence for
  new physics in the unitarity triangle beyond the
  SM.
• Modes dominated by penguin amplitudes as B0 ? fK0
  seem to be promising benchmarks for New Physics
  at a mass scale lt 1 TeV. However unravelling the
  full flavour impact of this new physics will
  require a very high luminosity B Factory a
  Super-B Factory (luminosity higher by a factor
  50-100 than in the present machines).

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Backup Slides
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Results on sin2b from ccs, dcc modes
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B flavor tagging and Dt measurement
Tagging performance QT30.5 (6 categories) from
full Neural Network including these other
physics processes to identify b quark state
perfect resolution
smeared resolution
?t resolution dominated by tag side s(Dt) ? 1
ps ? 170 ?m
?B ? 1.6 ps ? 250 ?m
CP asymmetry
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cos2b from B0 ? J/yK0(KSp0)

• J/yK0 (KSp0) final state can be hF 1 or hF
  -1, depending on L 0, 1, 2
• Full angular analysis allows for the separation
  of CP even (A A e id , A0 A0 e id
  0) and CP odd (A? A? e id ?)
• Many terms in time-dependent decay rate, but two
  are proportional to cos2ß

BABAR
BABAR
(with sin(2ß) fixed to 0.731) Sign ambiguity is
related to the sign of strong phase difference

• Use interference of s-wave and p-wave
  contributions to Kp final state to resolve sign
  ambiguity for strong phases

? solution 1 unphysical solution
? solution 2 physical solution
? LASS data
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Dalitz analysis of B- ? D()0KSpp-K-
2
Schematic view of the interference