Amir Farbin University of Maryland (BaBar Collaboration)

Measurement of Time-Measurement of Time-dependent CP Asymmetries dependent CP Asymmetries

& New Physics Searches with & New Physics Searches with Rare B Meson DecaysRare B Meson Decays

(B(B00++-- & B & B00KKss00))

Amir FarbinAmir Farbin

University of MarylandUniversity of Maryland

(BaBar Collaboration)(BaBar Collaboration)

OutlineOutline• Some B physics background/notation

• Describe 2 time-dependent measurements in 2-body charmless B decays in the context of how they test the SM

• Method 1- CKM consistency tests.

• B0 measures (one ingredient)

• first t-d measurement in rare mode- First measured for LP01. I’ll present LP03 results.

• Method 2- Search for new physics effects.

• B0Ks sensitive to SUSY, ED, etc…

• thought unmeasureable

• Presented at LP03

• Since the 2 analyses are very similar, I’ll describe most of the details when describing B0.

• Give some idea of future prospects.

Observing CP ViolationObserving CP Violation

1. CPV in Decay (Direct)

Requires contributions from at least 2 amplitudes with:

• Different CP-even phases

• Different CP-odd phases

-,0 +,0Γ(B ) Γ(B )f f

2. CPV in Mixing

W W

b d

bd

t

t

0B 0B

*tbV tdV

*tdV tbV

00

00

| | | ,

| | | .

L

H

B p B q B

B p B q B

1

p

q

3. CPV in Interference between Mixing and Decay

• In decays of neutral mesons to a CP eigenstate ( )f f

• CPV is elusive- 36 years between discoveries in K’s and B’s

0B

0B

CPfCP

mixing

decay

CPfA

CPfA

• Interference effect. 3 observable types of CPV:

Cabbibo-Kobayashi-Maskawa Matrix

dd ss bb

uu VVudud VVusus VVubub

cc VVcdcd VVcscs VVcbcb

tt VVtdtd VVtsts VVtbtb

CKM2 (V h.c.2

)iL

jijL

gu Wd

WL

Connect: up quarks, down quarks, and W-bosons

The CKM Matrix:

• Unitary

• 4 Free parameters:

• 3 Real

• 1 Imaginary

• CPV w/ >2 Generations

u

d

W+

Vud

u

d

W-

V*ud

CP

Only CPV in SM (quarks)

Flavor Changing Interactions in Flavor Changing Interactions in SMSM

VVududVV**ubub + V + VcdcdVV**

cbcb + V + VtdtdVV**tbtb =0 =0

)(O

1A)i1(A

A21

1

)i(A21

1

VVV

VVV

VVV

V 4

23

22

32

tbtstd

cbcscd

ubusud

Wolfenstein Parameterization

Represented as triangle

Relate angles to decays of B’s to CP Eigenstates

Unitarity

The CKM Matrix (Notation)The CKM Matrix (Notation)

VtdVtb*

VudVub*

VcdVcb*

2 6Area A

3 real parameters: A, ,

1 complex phase: = |Vus| 0.2200 0.0025

A = |Vcb| / 2 0.83 0.05

(,) not well known

Testing CKMTesting CKMCheck that CP violation in the quark sector is fully encapsulated by the CKM matrix:

a. Constraints in the plane:

Meth

od

1

• Using indirect measurements:

sin 2=0.727±0.036

• B meson system B0J/ K0 decays:

sin 2=0.739±0.048 First triumph of B factories: CKM phase dominant source of CPV

Lots of effort into improving the inputs.

A. Hocker, et al.

32 CL range: 0.118-0.273

0.305-0.393

2(1 / 2) 2(1 / 2)

b. Check the unitarity of CKM matrix: Independently measure Unitarity Triangle angles and test closure: (New physics test)

Hampered by experimental (low statistics) and theoretical (hadronic uncertainties) difficulties.

If no inconsistency is found precise measurements of fundamental SM parameters

Time dependent analysis of B0+- is sensitive to the angle

CP

CP

CP

f

ff A

A

p

qλ

Decay amplitude

ratio2

2

1

1

||λ

||λC

CP

CP

CP

f

ff

2||1

Im2

CP

CP

CP

f

ffS

ModeMode

ππB0

s0 K J/B

CPfλ )Im(λCPf

*cscd

*cdcs

*cbcs

*cscb

*tdtb

*tbtd

VV

VV

VV

VV

VV

VV

0 0

0 0

( ( ) ) ( ( ) )

( ( ) ) ( ( ) )CP

CP CPf

CP CP

B t f B t fA

B t f B t f

tmCtmS dfdf CPCP cossin

Measuring Angles with BMeasuring Angles with B00’s’s

Measure the time-dependent decay asymmetry

*ubud

*ubud

*tdtb

*tbtd

VV

VV

VV

VV

2sin

Treeb u,c

cu ,

d,s

W

2sin

mixingOscillate w/ mixing freq

Amplitudes:

Look at interference between decay and mixing.

BB00++-- Decays Decays (Not so simple)(Not so simple)

Hadronic Penguin Amplitude Hadronic Penguin Amplitude (P)(P)

Tree Amplitude (T)Tree Amplitude (T)ModeMode

Eff2iαππα)i(δ

T

P

α)i(δT

P2iα

ππ e|λ|e-1

e-1eλ

b u,ccu ,

d,s

WW

t

b d,s

u

u

g

iγ3*udub eλVV~

2*cscb λVV~

iβ3*tdtb eλVV~

iγ42 )eO(λλ~ ππB0

s0 K J/B

πKB0 iγ4*usub eλVV~ 2*

tstb λVV~

“ Effective”

• In the case of B0J/ Ks Tree/Penguin carry same phase Measure sin 2

• Br(B0K+-) >> Br(B0+-) Penguin contributions may be large

• But for B0+- Tree/Penguin may contribute w/ different phases

PEP-II accelerator schematic and tunnel viewPEP-II accelerator schematic and tunnel view

DeliveredRecorded

Total:

Lint=113 fb-1

121M B’s

(used here)(1x1033 cm-2 s-1 ~ 1 B pair/s)

9 GeV e-

3.1 GeV e+

SLAC’s Asymmetric B SLAC’s Asymmetric B FactoryFactory

Record: L=6.696x1033 cm-2 s-1

ILER=1750 mA, IHER=1070 mA,

939 bunches

The BaBar DetectorThe BaBar Detector1.5 T solenoid

Electromagnetic Calorimeter• 6580 CsI(Tl) Crystals• E/E= 3.0%• 3.9 mrad

Drift Chamber• 80:20 He:C4H10

• 7104 Hexagonal Cells

• 40 layers (24 stereo)• =0.1-0.4 mm

e- (9 GeV)

9 meters

Silicon Vertex Tracker• Double sided strip

detectors (z-)• 5 layers, 340 wafers• =15-40 m

Cerenkov Detector (DIRC)

• Radiator 144 quarks bars• Image Ring on 896 PMTs• c = 2.5 mrad/trk

Tracking• pt= 0.13% pt + 0.45%• d0= 23 m • 0= 0.43 mrad• z0= 29 m• tan= 0.53 x10-3

Instrumented Flux Return• 19/18 Layers of RPC (Barrel/EndCaps)• 20-38 mm segmented (z-or x-y)• 2-10 cm Iron in between• =60% w/ < 2.5% mis-id

e+ (3.1 GeV)

•Large background from

(~1100/325 Event/fb-1 before/after selections)

Use multivariate techniques to discriminate against background.

BB00++--, K, Kss00 Decays Decays

e e qq, (q u,d,s,c)

•Two-body decay: two back-to-back 2.6 GeV/c particles in CM

Hardest particles from any B decay No B bkgs

Effects PID & resolution of kin vars

•Rare Decays: Branch fractions ~ 10-6 - 10-5 (~ 1-10 events/fb-1)

Maximize efficiency: loose selection + global likelihood fit.

• B0 ++--:: must separate B+-,K+-,K-+,K+K-

BaBar’s Ring Imaging Cherenkov detector (DIRC).

• B0KKss00: : No tracks from B decay vertexNo tracks from B decay vertex

Use extra constraints to determine decay point along beam.

The Observables The Observables

• KinematicsKinematics

• Event shapeEvent shape

• Particle IDParticle ID

• B Decay pointsB Decay points

• B FlavorB Flavor

KinematicsKinematics*2 2

ES beam*Bm E p * *

beamBE E E

((mmESES) ) 2.6 MeV/c 2.6 MeV/c22 ((EE) ) 26 MeV 26 MeV

• Resolution dominated by the small spread in beam energy (10.58/2 GeV)

• Insensitive to reconstructed mode

• Dominated by tracking resolution

• Unique for every decay

• Assume shift for K and KK

Background

Signal

K KK

(All distributions are normalized to the same area)

340MeV

Background

Nearly orthogonal

B0Ks0 B0Ks0

Tail from EMC leakage

Tail from EMC leakage

Background SuppressionBackground Suppression

All background from All background from

where picked 1 track fromwhere picked 1 track from

each fragmenting quarkeach fragmenting quark

e e qq, (q u,d,s,c)

0 0e e B B ,hh X

e e uu

“Jets”

Candidate

Axis of “Rest Event”

Axis of “Rest Event”sθ

sθ

Signal

Background

Angle btw candidate and “Rest of Event”

axes. (cos s)

Optimized linear combination of event shape variables (Fisher Discriminant)Cut

Signal

Background

• DIRC DIRC cc resolution and resolution and KK-- separation separation measured in data measured in data D D**++ D D00++ ( (KK--++))++ decaysdecays

Particle Identification (DIRC)Particle Identification (DIRC)

((cc) ) 2.22.2 mrad mrad>9

2.5

K/ Separation

Momentum range of 2-body B Decays at BaBar

Measuring Time-dependent Measuring Time-dependent CPVCPVTime/flavor-structure of the (4s) system:

0 0Tag

0

| |4

|

0

00Tag

|4

( / , , ) e [1 + sin( ) cos( )]

( / , , ) e [1 sin( ) cos( )]

ft

t

f

f f

B

B

t m t m t

t

S C

S Cm t

B

mB t

B

B

( ) ( )( ) sin cos

( ) ( ) f f

t tA t m t m t

tS C

t

4s

+e-e

z

Brec

Btag

zCoherent BB pair

B0

B0

+

-

t z/c

(4S) = 0.55 Fully Reconst.ed

Know Vertex

Inclusively Reconst.

the Vertex and Flavor

• B lifetime ~ 1.54 ps

<|z|> ~ 260 m• Inclusively reconstruct BTag vertex

• Background has “no” lifetime

Measuring of decay time Measuring of decay time difference difference tt

(4s)

= 0.55

Tag B

z ~ 180 m

CP Bz ~ 45 m

+z

t z/c

K0

-

Average z resolution: 190 m

Background

Signal

• Exploit correlation between b-quark flavor & charges of final decay products

• 7 algorithms look for 4 signatures

b c

d d

l-

B0 D, D*

W- 0

0

l

l

B

B

1. Lepton

b

d

B0

W- W+

c s

K-

d

0

0

0

0

kaons

kaons

Q

Q

B

B

2. Kaon

uu

(B Flavor Tagging)

4. Hard Pion

3. Soft Pion

Overall Q ~ 28%(Errors on S & C ~ w/ 1/Q)

Tagging ~70%

Kin & PID PID

Kin

Separating BSeparating B00 and and BB00 mesonsmesons

Extracting SExtracting S & C & C

B0h+h’- candidates ES

1c

2c

Δt

m

ΔE

F

θ

θ

Δt,σ

Tag

Max

imu

m L

ikel

iho

od

Fit

Signal/Background Yields

candidates

01

( )B D π /ρ /a ES

Δt

m

Δt,σ

Tag

Params of:

• Sig mES, E, F from MC/data

• c from D*

Signal t & Tagging params

Measure: S & C

•Possible due to the inclusion of large side-bands.

•Provides more accurate/simplified parameterization of the background

•Smaller/simpler systematic errors

Bkg mES, E, F, t, & Tagging params

•Possible due to the inclusion of flavor sample

•Smaller/simpler systematic errors.

•Allows measuring the branching fractions for B,K,KK & the direct CP asym in BKK

Some ValidationsSome Validations• Blind analysis don’t look at the answer until ready

• Extensive Monte Carlo tests including specialized Toy MC

• Large number of BK in sample measure

• B=1.602± 0.058 ps (World Avg: 1.542 ± 0.016 ps)

• md=0.472 ± 0.036 ps-1 (World Avg: 0.489 ± 0.008 ps-1)

• SK=0.02 ± 0.15, CK=0.09 ± 0.11 (Expect SK=CK=0)

unmixmixi

ed

unmixe

mixed

mixedn

dg

( ) ( )( ) cos

( ) ( )

t tA t m t

t t

We can properly measure to time/flavor dependent quantities in the Bhh sample.

Likelihood selected sample of signal BK candidates

BB00Results Results 0.40 0.22 0.03

0.19 0.19 0.05

S

C

Background

B0 Tags

B0 Tags

Likelihood selected sample of B candidates

266 24N

B0K+-

Extracting Extracting from S from S & C & C

• CKM fit using other measurements

• SU(2)- Isospin symmetry & B

• SU(3)- Flavor symmetry & B0K+

• SU(3)- Flavor symmetry & B+K0

• QCD Factorization

0.080.071.23 0.41

0.77 0.27 0.08

S

C

Belle winter 03 (78 fb-1):

0.40 0.22 0.03

0.19 0.19 0.05

S

C

BaBar summer 03 (113 fb-1):

A. Hocker, et al.

0.58 0.20

0.38 0.16

S

C

Average:

Consistent w/ SM

Note current experimental accuracy

Comment on “Isospin” AnalysisComment on “Isospin” Analysis

0 0 0 0 0 0 0 0 0 0, , , , ,B B B B B B Use SU(2) isospin symmetry to relate the rates of

Provides only theoretically clean method of obtaining from Eff (with 4-fold ambiguity)

• B000 recently observed by BaBar w/ large branching fraction: 2.1 ± 0.6 ± 0.3 x 10-6

• Quinn-Grossman bound:

Not very useful: |-Eff|<48o @ 90% CL

• Even with flavor tagged rates might need 10 ab-1

• New hope: B0+-

•~100% longitudinally polarized CP even.

• Similar stat error on S & C

• B(B000) is very small |-Eff|<14.7o

0 02

Eff 0

( )sin ( )

( )

B

B

BB

Testing CKM Testing CKM (cont’d)(cont’d)Search for new physics: Study decays whose leading contributions are from loop diagrams and may therefore deviate from SM prediction due to new physics.

Meth

od

2

B0Ks0 is the most recent addition to these modes.

2.13.5

Current Status:

• 4 measurements

• Large Statistical Errors

• Deviation in B0Ks???

a. Branching fractions: Ex: bs

b. Direct CP violation: Ex: BK*

c. Time-dependent CP violation: Compare sin 2 from bsuu, bsdd, bsss to bscc (ie BJ/Ks)

W

t

b s

, ,u d s

, ,u d s

g

* 2 Im sin 2tb ts f f fP V V S

W

t

b ,s d

or

BB00 K Kss 00 Decays DecaysB0 Ks 0 is a penguin dominated decay to a CP eigenstate: b u

u

s

W

d d

W

tb s

d

d

g

d d* 4 i

ub usT V V e * 2tb tsP V V

Cabbibo & Color Suppressed

A time-dependent analysis: P measures sin 2

Maximal deviation in SM from sin 2 due to dynamical enhancement SKs0-sin 2<0.18

Usual arguments of sensitivity to new physics in loop diagrams applies

Grossman, Ligeti, Nir, Quinn (hep-ph/0303171)

Gronau, Grossman, Rosner (hep-ph/0310020)

Constrain in x-y to beam-spot

Reconstructing the BReconstructing the B00 K Kss 00 VertexVertex

Btag- Standard Method

Beame+e-

4s0

Ks

+

-

Only have vtx info here

yz

0B

0B

Inflated Beam

yx

Beam

0

+ -

Ks

~30 m

~4 m~200 m

“Beam Constrained (BC) Vertexing”

0B

• Method works:

• Small beam size

• Good beam spot reco.

• t dominated by tag side

• Same principle for Btag vtx where there’s only 1 trk

Properties of BC vertexingProperties of BC vertexing• Resolution on z-position depends on number of SVT layers traversed by pions form Ks

• Belle has 3 (now 4) SVD layers problem?

SVT layers

• Ks flight direction

Expected dependence

(assuming perfect resolution but finite beam size)

Insufficient SVT hits for trk matching~50% res.

difference

cos

Ks x-y decay length distribution

BC vs Nominal Vertexing

Class I

Class II

Unique to BC Vertexing:

• Only vtx ~65% of decays (mode dependent)

• 2 Classes of events w/ different avg resolutions

Common to BC & Nominal Vertexing:

• Dependence of t resolution on estimated error t essential ingredient of resolution function

Mean of(tmeas- ttrue)

vs. t

RMS of(tmeas- ttrue)

vs. t

• We have no large sample of BC vertexed events.

Use same resolution function for nominal & BC vertexed samples.

• Use MC to estimate systematic for this choice.

Extracting S & CExtracting S & CClass I + II + III + IV events ES

Δt

m

ΔE

F

Δt,σ

Tag

Max

imu

m L

ikel

iho

od

Fit

Signal/Background Yields

Bkg mES, E, F, t, & Tagging params

Params of:

• Sig mES, E, F from MC/data

• Sigt & Tagging params from Bflav

Measure: S & C

Use t for events in class I and II (~ 65% of events)

Gives S (& C) Use tagging for all tagged events

Gives C

Loose selection

high efficiency

ValidationsValidations• Since this is a “new” technique Since this is a “new” technique some validation. some validation.

• Control samples:Control samples:– BB00 J/ J/KKss: “Remove” : “Remove” J/J/ from B vtx by blowing up its vtx from B vtx by blowing up its vtx

parameters (Mangling)parameters (Mangling)

• Compare nominal/BC vertex event by eventCompare nominal/BC vertex event by event

• Compare data/MCCompare data/MC

• Compare sin 2Compare sin 2– SJ/Ks(nominal-BC)=-0.027 0.064

– CJ/Ks(nominal-BC)=-0.034 0.026

– BB++ K Kss++: “Remove” : “Remove” ++ from B vtx by blowing up trk parameters. from B vtx by blowing up trk parameters.

• Same kinematics as our decaySame kinematics as our decay

• Similar backgroundsSimilar backgrounds

• ““Null test”: Null test”: – SSKsKs++= 0.18±0.19= 0.18±0.19

– CCKsKs++= 0.06±0.11= 0.06±0.11

BB00KKss 00 Results Results0.38 0.410.47 0.480.48 0.11 0.41 0.11S S

0.270.280.40 0.10 Fixed to 0C C

Ns=122±16

Background

B0 Tags

B0 Tags

Consistent w/ B0J/Ks

Beyond SM Prospects in B Beyond SM Prospects in B PhysicsPhysics

Goto, Okada, Shimizu, Shindou, Tanaka (hep-ph/0306093)

Pessimistic:

• There are enough SUSY parameters/SUSY breaking models to accommodate any scenario… including no signature in B physics.

• Each measurement probes a different aspect of new physics.

• Example: B0Ks could be the only New Physics signature.

= Non-negligable deviation from SM

Large SUSY contributuions

Optimistic:

• Multiple SUSY signatures in B physics.

• Time-dependent asymmetries are more sensitive probes than BRs and direct CPV.

• B factories will (at least) tighten new physics limits.

Theorist:(example)

Questions:1. What is the likelihood of

seeing new physics?

2. What can we learn from an “observation”?

3. How do we relate measurements from different channels? (ie how do we understand current measurements?)

Important to check all experimentally accessible decays

New Possibility: BNew Possibility: B00KK**, , KK**KKss00

• B0Ks0 final state with extra photon Use BC vertexing

• The dominant SM amplitude gives opposite photon helicities for

• New physics enhance SK* up to 50% of sin 2

• Related to B0Ks. New physics should be apparent in both!

David Atwood, Michael Gronau, Amarjit Soni (1997) (hep-ph/9704272)

W

t

b s

0 0/B B

* 2 sin 2 0sK

b

mS

m

0B

0B

*LK

mixing

CPfA

CPfA

*RK

Helicity Flip Suppressed by ms/mb

Expect:

• bs decay: BB00KK**, K, K**KKss00 CP Eigenstate- 11% CP Eigenstate- 11%BB00KK**, K, K**KK++-- Self-tagging- 89% Self-tagging- 89%

Experimental ProspectsExperimental ProspectsModeMode SS(current)(current) SS(200/fb)(200/fb) SS(500/fb)(500/fb) ||ff||

B0K0 0.430.43 0.260.26 0.160.16 <0.25<0.25

B0K+K-Ks0.250.25 0.190.19 0.120.12 <0.14<0.14

B0’Ks0.340.34 0.220.22 0.140.14 <0.09<0.09

B0Ks0.430.43 0.320.32 0.210.21 <0.13<0.13

B0K*0 ---- 0.530.53 0.340.34 N/AN/A

B0Ks Ks Ks---- ?? ?? ??

B0Ks---- 0.50.5 0.30.3 ??

Summary• It is possible to “observe” new physics in most modes, if the deviation from SM is large.

• Considering the current BaBar’s measured values it’s more difficult!

• Many more modes to come soon…

Estimated maximal deviation from sin 2

SummarySummary• The angle The angle ::

– Though the BThough the B00was the “golden-mode” for was the “golden-mode” for and the first time-dependent analysis in a rare B and the first time-dependent analysis in a rare B decay, the large Bdecay, the large B00 branching fraction makes branching fraction makes extraction of extraction of in the near future unlikely. in the near future unlikely.

– BB00 is promising… is promising… with 10 with 10oo uncertainty in uncertainty in the next few years? the next few years?

• New physics:New physics:– Belle’s BBelle’s B00KKss has everyone excited now. has everyone excited now.– We’ll know in 1-2 years if it is real.We’ll know in 1-2 years if it is real.– The BThe B00KKss00 measurement has opened the door to measurement has opened the door to

previously inaccessible analyses. previously inaccessible analyses. – BB00KK** is promising. is promising.– Many more time-dependent analyses ahead.Many more time-dependent analyses ahead.

Backup SlidesBackup Slides

Branching Fraction ResultsBranching Fraction ResultsModeMode YieldYield Branching Fraction (10Branching Fraction (10--

66))

0.102 0.050 0.016KA

πKB0

ππB0

KKB0

4.6 0.6 0.2

17.9 0.9 0.7 0.6 (90% CL)

156.5 18.9 6.5 11.316.5588.5 29.6

0.8 7.7( 15.9)

Likelihood projections:• Remove 1 variable from fit• Cut on probabilities used in fit

ππB0 πKB0

0.107 0.041 0.013KA

sJ/ΨKsin 2 ( 1)f fS S When is

sin 2 2cos 2 sin cosf f f ffSS 2sin sin ff fC

*

*

uus ub f

f ccs cb f

V V a

V V a Arg

uf

f cf

a

a

* * * (1 )c u cf cs cb f us ub f cs cb f fA V V a V V a V V a

CKM Suppressed

Grossman, Ligeti, Nir, Quinn (hep-ph/0303171)

Gronau, Grossman, Rosner (hep-ph/0310020)

indication of new physics?

Dynamical enhancement can make |f| >> 0

Use SU(3) and branching fractions to bound |f|

Looking for NP with time-dependent Looking for NP with time-dependent CPVCPV

W

t

b s

, ,u d s

, ,u d s

g

* 2

Im

sin 2

tb ts

f f

f

P V V

S

W

t

b ,s d

Decays which are dominated by penguin AND are sensitive to sin 2(since is well-known)

or

Tree amplitudes are generally CKM suppressed

Very conservative estimate…

t Resolution Bottom Linet Resolution Bottom Line

B0J/Ks

(mangled)<

B0Ks0

= B+Ks+

(mangled) <

B0J/Ks

(Nominal)

t resolution vs. cos Ks

t

Res

olu

tio

n

Best

Worse

Class I + Class II Events

Diagrams

BaBar/Belle status/plans• Belle has submitted a PRL

• BaBar: KL’s were not included in LP03 result, but will be in upcoming PRL

• Ks00 will be added next

• Summer 2004 Update

Theory

• Insufficient experimental data to bound Ks

Must use B+K+ and “cancellation assumptions” to relate K+ K0 (Not solid)

Ks|~ |K+|< 0.25

Comments

Need: Branching fractions for: B0AA’, A={’K0,K*0}

Used: Branching fractions for: B+VP+, V={K*0}, P={K+,+}

B0K0 CP= -1 (Ks), +1 (KL)Stefan SpanierMahalaxmi Krishnamurthy

BaBar BaBar (114/fb)(114/fb)

Belle Belle (140/fb)(140/fb)

SS KKss

KKLL

KK00

0.45±0.43±0.070.45±0.43±0.07

?.??±0.67?.??±0.67

?.??±0.34±0.06?.??±0.34±0.06

--0.96±0.50±0.10.96±0.50±0.100

CC KKss

KKLL

KK00

--0.38±0.37±0.120.38±0.37±0.12

?.??±0.82?.??±0.82

?.??±0.33±0.13?.??±0.33±0.13

0.15±0.29±0.00.15±0.29±0.077

NNSS KKss

KKLL

70±970±9

52±1652±166868

NNBB KKss

KKLL

~18~18

~191~191~38~38

KKss

KKLL

0.433±0.0030.433±0.003

0.217±0.0020.217±0.002

Stats

Ks Only: S(200/fb)=0.32, S(500/fb)=0.21

Ks + KL: S(200/fb)=0.26, S(500/fb)=0.16

(Example) Diagram

BaBar/Belle status/plans

• Belle has submitted a PRL while BaBar hasn’t presented yet.

• Denis: “If I don’t hear from the Review Committee, I’ll unblind next week.”

• BaBar plans for Helicity analysis for winter.

• Belle is also working on Dalitz analysis. (suggested by speaker on Tuesday)

Theory

• Requires Isospin or Helicity=Dalitz analysis to determine CP content

• Use U(2) KKK|< 0.14

Comments

• Use: Branching fractions for: B0h+h-h’+, h={K}

• Note: BaBar isospin analysis uses Belle’s K+KsKs

• Helicity analysis reduces uncertainty on CP content by factor 2

B0K+K-Ks CP= MixedDenis Dujmic


Belle (140/fb)Belle (140/fb)

SS ?.??±0.25±?.???.??±0.25±?.?? 0.51±0.26±0.050.51±0.26±0.05+0.18+0.18--

0.000.00

CC ?.??±0.19±?.???.??±0.19±?.?? 0.17±0.16±0.040.17±0.16±0.04

ffOddOdd ?.??±0.22±?.???.??±0.22±?.?? -0.03±0.15±0.05-0.03±0.15±0.05

NNSS 249±20249±20 198198

NNBB ~151~151 ~162~162

23%23%

Stats

Isospin analysis:100% CP Even

Requires Isospin or Helicity=Dalitz analysis to determine CP content

S(200/fb)=0.19, S(500/fb)=0.12

BLIND

Diagrams


• Belle has submitted a PRL

• BaBar:

• Run 1-3 update by winter

• Run 1-4 update by summer

Theory

• For B0‘Ks: ;K|< 0.36

• Bound on B+‘K+ is better (more accurate BR measurements): ;K|~;K+|< 0.09

Comments

• Use: Ratios of branching fractions: B0AA’, A={’} (13 modes)

B0’KsCP= -1Frederic Blanc, Fernando Palombo, Paul Bloom, Bill

Ford, Mirna van Hoek, Jim Smith, Alfio Lazzaro


Belle (140/fb)Belle (140/fb)

SS --0.02±0.34±0.00.02±0.34±0.033

0.43±0.27±0.050.43±0.27±0.05

CC 0.10±0.22±0.00.10±0.22±0.033

0.01±0.16±0.040.01±0.16±0.04

NNSS 51±2851±28

150150± 17± 17

244244

NNBB 1818

122122

~176~176

23.8%23.8%

22.6%22.6%

Stats

S(200/fb)=0.22, S(500/fb)=0.14

Diagram


• BaBar: Reworking systematics now

• PRL Draft by end of October

• Update summer 2004

• Belle: Surprised at LP03.

• Likely to have difficulty since their SVD has only 3 (now 4) layers

Theory• Cleaner than other modes: K|< 0.13 M. Gronau, Y. Grossman, J. L. Rosner (hep-ph/0310020)

Comments

• Use: B00 0 and B0K+K- only

• Better B0K+K- UL would help

B0KsCP= -1AF, Wouter Hulsbergen, Dmytro

Kovalskyi, Maurizio Pierini

BaBar (114/fb)BaBar (114/fb) Belle Belle

SS

CC

NNSS 122±16122±16

NNBB 134134

29%29%

Stats

S(200/fb)=0.32, S(500/fb)=0.21

W

tb s

d

d

g

d d

Experiment

• Expected to be impossible (no track from B vertex)

New Beam-Constrained Vertexing technique Good Vertex ~ 65% of events

• Technique validated on B0J/Ks

0.380.470.48 0.11

0.270.280.40 0.10

Diagram


• BaBar: Planning measurement for winter 2004.

• Belle: Obviously is aware of the prospect

• Likely to have difficulty since their SVD has only 3 (now 4) layers

Theory

• The dominant SM amplitude gives opposite photon helicities

Expect:

• New physics enhance S up to 50%

B0K*0(K*0Ks0) CP= -1AF, Wouter Hulsbergen, Dmytro Kovalskyi, Maurizio Pierini


SS Estimated Error ~ Estimated Error ~ 0.840.84

CC Estimated Error ~ Estimated Error ~ 0.560.56

NNSS 61.8±15.361.8±15.3

NNBB 172172

18%18%

Stats

S(200/fb)=0.53, S(500/fb)=0.34

Experiment

• Apply same technique as B0Ks

David Atwood, Michael Gronau, Amarjit Soni (1997) (hep-ph/9704272)

0 0/B B

2 sin 2 0s

b

mS

m

Diagram


• BaBar: ?

• Belle: ?

B0Ks Ks Ks CP=+1Steve Wagner


SS Estimated Error ~ ?Estimated Error ~ ?

CC Estimated Error ~ ?Estimated Error ~ ?

NNSS ~21~21

NNBB

5-6%5-6%

Stats

S(200/fb)= ?, S(500/fb)= ?

Experiment

• Using B0Ks technique will allow vertexing candidates with only 1 Ks decaying before 4th SVT layer

BLIND

Not enough info to estimate errors

(4S)

Ingredients for Measuring CPV w/ Ingredients for Measuring CPV w/ B’sB’s

0 0

0 0

( ( ) ) ( ( ) )

( ( ) ) ( ( ) )CP

CP CPf

CP CP

B t f B t fA

B t f B t f

In order to measure: 1. Produce many B mesons

2. B lifetime is small Provide a boost to measure B decay time

3. B CP eigenstates are rare Efficient Reconstruction of fCP

4. Determine t & B0/anti-B0

Asymmetric B Factory

Detector w/ PID & Vertexing

Measure Angle of Cherenkov Cone in quartz

– Transmitted by internal reflection– Detected by PMTs

Particle Identification (BParticle Identification (B00++--))((DDetector of etector of IInternally nternally RReflected eflected CCherenkov Lightherenkov Light))

c

Particle

Quartz bar

Cherenkov light

Active Detector Surface

c1cos θ , p mβnβ

Interpreting the ResultsInterpreting the Results

Eff

P i(δ α)2iα2iα T

ππ ππP i(δ α)T

1- eλ e |λ |e

1- e

2

2

1

1

| λ |C

| λ |

2

2Im

1 | |S

• Recall thatAq

λp A

0 Direct CP ViolationC 0 CP Violation in interference between mixing & decayS

• If decay dominated by tree amplitude (T) then

Im sin 2 • But expect large penguin contribution (P) to decay so

is relative strong phase between P and T

0.40 0.22 0.03

0.19 0.19 0.05

S

C

The Big Bang

Cosmology

Baryogenesis(Sakharov Conditions)

Particle Physics

InflationSupersymmetry/

Extra-Dimensions

Standard Model

(Current Theory)

Strings

Science of the smallest scale

Science of the largest scales

Astronomy

CP Violation= Matter/Anti-matter

asymmetry

Seen on both sides

Observe: All matter

1 Param

Observe: K’s & B’s

Predicts more CPV

Necessary ingredient

CP Violation and the Universe

Assessing Assessing t and t and bb-flavor -flavor TaggingTagging

01

( )B D π /ρ /a

50 times larger

than signal

• Need to measure the t resolution

• Need to measure the b-flavor “mis-tag” rates, efficiencies, etc…

• Use “self-tagging” B0 decays…

Know the flavor of the fully reco’d B check determination of the flavor of BTag Ex: B0 D- + (K- +-) +

0 0Rec Tag

0 0Tag Recun

0 0Rec Tag

0 0Re

| |4

| |

mixed mixed

c Tagmixed unm xe 4i d

( , , ) ( , , ) e [1 cos( )]

( , , ) ( , , ) e [1 cos( )]

t

t

B t t m t

t t m t

B B

B B

B

B B

mixed

m

unmixed

unmixmixing

ed ixed

( ) ( )( ) cos

( ) ( )

t tA t m t

t t

Mistag

unmimi

xexing

d

unmi

mixed

mie edx xd

( ) ( )( ) (1 2 )cos

( ) ( )

t tA t w m t

t t

Add tagging

effect

(lot more stuff)

Event ClassesEvent ClassesThe dependence on the # of SVT layers traversed by Ks daughters necessitates the identification of 4 classes of events:

• Class I (Red)- 1 z & 1 hit in layers 1-3 on both tracks

Nearly same t resolution as “nominally” vtx’ed decays

• Class II (Blue)- Remaining events w/ 1 z & 1 hit in layers 1-5 on both tracks

~ ½ t resolution as “nominally” vtx’ed decays

• Class III (Black)- Only 1 SVT hit on either track

• Class IV (Green)- No SVT hits

t resolution

Selection Efficiency

(Difference due to different Ks spectrum)

Documents

Amir Farbin University of Maryland (BaBar Collaboration)