Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP...

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Observation of CP Violation at Belle HEP Seminar Brookhaven National Lab Daniel Marlow Princeton University November 8, 2001

Transcript of Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP...

Page 1: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Observation of CP Violation at Belle

HEP SeminarBrookhaven National Lab

Daniel Marlow Princeton UniversityNovember 8, 2001

Page 2: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Talk Outline

• Introduction/Review (with apologies to the experts)

• The KEK-B Collider• The Belle Detector• Indirect CP Violation Measurement/Analysis• Conclusions

Page 3: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Physics MotivationDirect CP violation is perhaps the simplest case. Consider the CP mirror processes:

))())(

fBfBfBfBACP →(Γ+→Γ

→(Γ−→Γ≡

fBfB →→ and The CP asymmetry is defined as

The decay amplitudes are

and SWSW iiff

iiff eeAAeeAA φφφφ −==

Note that the weak phase changes sign.

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November 2001 CP Violation at Belle

Direct CP ViolationNote that

Yielding

22

ffff AA Γ=Γ⇒=

221121

SWSW iiiif eeAeeAA φφφφ

+=

221121

SWSW iiii

f eeAeeAA φφφφ −−+=

We need some sort of interference, two amplitudes, for example

)cos( 2 212

22

1 SWf AAAA φφ ∆+∆++=Γ

)cos( 2 212

22

1 SWf AAAA φφ ∆−∆++=Γ

Page 5: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Direct CP ViolationDespite its conceptual and experimental simplicity, there are two problems with direct CP violation:

• Cases where there are two comparable amplitudes that are large are (probably) rare.

• The strong phases are poorly understood, making it difficult to extract the weak (KM) phases that are of greatest interest.

One is thus led in the direction of asymmetric e+e- B factories aimed at the study of indirect CP violation.

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November 2001 CP Violation at Belle

Indirect CP Violation

( ) ( )[ ]022

02

(0 sincos)( BeiBetB mimtmtimi φ−∆∆)/2Γ−− +×=

In this approach we provide the interference using state mixing, i.e.,

00BB

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November 2001 CP Violation at Belle

Indirect CP ViolationThus for a decay where is a CP eigenstate, we have two “indistinguishable” decay paths

fB →0

f0B0B f

Working through the algebra, yields a time-dependent CP asymmetry )(2sin)sin(

)()()()()( 00

00

DMf

CP

tmfBfBfBfBtA

φφη +∆∆−=→Γ+→Γ→Γ−→Γ=∆

Mφ DφWhere and are the weak phases for the mixing and decay diagrams, respectively and 1 ±=

=

f

f ffCPη

η

Page 8: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

The Kobayashi-Maskawa Mixing Scheme

Where the second matrix is the Wolfenstein parameterization.

0* =++ ∗∗tbubtsustdud VVVVVV

Quark mixing is described via

The “d b” unitarity relation yields 3* λAVV ubtd ≈+

−−−−−

−−≅

=

1)1(21

)(21

23

22

32

ληρλλλλ

ηρλλλ

AiAA

iA

VVVVVVVVV

M

tbtstd

cbcscd

ubusud

Page 9: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

CP Phases in the Gold-Plated Mode

0≈DφSKJB /0 Ψ→

)arg( tdM V≈φ

Decay

Mixing

The KM phase comes from the mixing.

Page 10: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

The Unitarity Triangle

η

ρ

3λAVtd

( )ηρ,

( )0,1

3λAVub

3

*

λAVV tsus

The gold-plated mode determines the angle which is also called .

β

1≈≈ tbud VV

Page 11: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Constraints

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November 2001 CP Violation at Belle

Existing Constraints

Höcker et al. hepex/0104062

Eur.Phys.J. C21 (2001) 225-259

sin2β results are average prior to July 2001. They are notincluded in the fit.

Page 13: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

The Measurement

0B

+µ−µ

0B

+µtag

CP

z∆

0DNeed to:

•Measure momenta

•ID leptons & K’s

•Measure vertices

−e +e

0K

Ψ/J

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November 2001 CP Violation at Belle

B0 B0

SKJB Ψ→ /0

The MeasurementThe time-dependent asymmetry appears mainly as a mean shift in the distribution between events tagged

as decays and

events tagged as

decays.

z∆

0B0B

1

00

00

2sin)sin( )()()()()(

ϕtmfBfBfBfBtACP

∆∆−=→Γ+→Γ→Γ−→Γ=∆

Page 15: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

The KEKB Asymmetric e+e- Collider

KEKB is similar to PEP-II in many ways, although there is an important difference in the way in which the beams are brought into collision.

−+ee

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November 2001 CP Violation at Belle

KEK B Asymmetric Collider

•Two separate ringse+ (LER) : 3.5 GeVe−−−− (HER) : 8.0 GeV

•ECM : 10.58 GeV at ΥΥΥΥ(4S)•Luminosity

•target: 1034 cm-2s-1

•achieved:5.2x1033cm-2s-1

•±11 mrad crossing angle •Small beam sizes:

σσσσy ≈≈≈≈3 µµµµm; σσσσx ≈≈≈≈ 100 µµµµm

asymmetric e+e−−−− collider

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November 2001 CP Violation at Belle

Beam Crossing SchemesBy colliding the beams at an angle, the KEK-B design achieves a simplified interaction region.

Moreover, every RF bucket (2 ns spacing) can be filled toachieve maximum luminosity. However, this approach risks destabilizing couplings between transverse and longitudinal modes of the machines.

A crab-crossing cavity is under development in case this proves to be a problem.

Page 18: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Machine Performance

Reported here

Summer ’01 shutdown

Integrated/day

Total Integrated

Page 19: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle Typical~good day.

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November 2001 CP Violation at Belle

Another Typical Day

This is probably a bit worse than usual.

Page 21: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

KEKB/PEP II Luminosity Bakeoff

1865 pb-11661 pb-17 day

59.6 fb-137.6 fb-1Integrated

291 pb-1277 pb-124 hour

103.2 pb-192.8 pb-1Shift

Peak

PEP-IIKEKB

1233 scm 102.5 −−× 1233 scm 103.4 −−×

As of ~November 5, 2001 Comparisons not quite apples to apples.

Page 22: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

KEKB Future Prospects• Chief limitation recently has been the photo-electron instability in the LER.

• This has been reduced, although not fully mitigated by installing a solenoidal winding around much of the beam pipe (last ~500 m this summer).

• Past history has shown that the situation slowly improves, in a manner consistent with a reduction in quantum efficiency of the beam-pipe wall brought that is reminiscent of “scrubbing.”

• If that is the case, we can expect additional modest gains in luminosity, but it is hard to know.

Page 23: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Page 24: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

An international collaboration involving about 10 Countries, 50 Institutes, & 250 People

The BELLE Collaboration

Page 25: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Detector Performance! Silicon Vertex Detector

! σ ~ 55µm for 1GeV/c @ 90o

! Central Drift Chamber ! σp/p ~ 0.35% @ 1GeV/c! σπ (dE/dx) ~ 7%

! K± id up to plab=3.5 GeV/c! TOF (σ ∼ 95 ps)! Aerogel (n = 1.01 ~ 1.03)

! γ, e± with CsI crystals! σE/Eγ ~ 1.5% @ 1GeV

! KL and µ± with KLM (RPCs)! µ± : effic. > 90% ; ~2% fakes

Page 26: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

)(GeV/ 2cM −+ππ

2eff MeV/ 6.4 c=σ

−+→ ππ0SK

Mass Reconstruction

Belle

Page 27: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

CsI EM Calorimeter Performance

MeV 50>γE

tionReconstruc 0π

tionReconstruc γγη →

Page 28: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Vertex Detector

σ ~ 55µm for 1GeV/c @ 90o

Occupancy at present luminosity ~4%

Upgraded SVD coming:

• 4 layers

• Radiation hard

• Level 1 trigger

• Summer ’02 installation Excl. mode B lifetime

Page 29: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Belle: ToF & Aerogel

The ToF has a resolution of σ=100 ps, which provides π/K separation up to about 1.2 GeV/c, at which point the ACC array kicks in. The index of refraction of the counters varies as a function of angle, reflecting the boosted CM.

Page 30: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Belle: Aerogel

Barrel Module

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November 2001 CP Violation at Belle

Particle ID (dE/dx, ToF, & Aerogel)

++∗ → π0DD+−→ πK

Page 32: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

PID Bake Off

BaBar Belle

Looks like BaBar does better.

Page 33: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Muon Identification

µµµ

side- tagplus

/+−+

++

Ψ→

KKJB

Muons are important for the same reason. They are identified by the way in which they penetrate the iron return yoke of the magnet.

The gaps are instrumented with RPCs.

Page 34: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Putting it all together

( )( )−+−+→Ψ→ ππµµSKJB /0

Page 35: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Analysis Flowchart

Page 36: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

CP Mode Sample

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November 2001 CP Violation at Belle

J/Ψ Reconstruction

• Require one lepton to be positively identified and the other to be consistent with lepton hypothesis.

• For e+e-, add any photon within .05 of electron direction.

Page 38: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

B Reconstruction

*beam

*cand EEE −≡∆

( )2

cand

2*beam

−= ∑ pEmbc

!

Page 39: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Other Modes

Mbc

Total events = 76Bkgd ≈ 9 evts (12%)

000 ;/ ππ→Ψ→ SS KKJB

Page 40: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Ψ’ Modes

Both leptons tagged.

Page 41: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Other Charmonium Modes

M(l++++l−−−−γγγγ) −−−− M(l++++l−−−−)

1st observationof inclusiveB→→→→ χχχχc2 X

χχχχc2

χχχχc1

Page 42: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

CP Even Mode (B→J/ΨKL) Reconstruction

KL hits

KL

LKJB Ψ→ /0• Assume(2-body) kinematics.

• Look for KL recoiling from J/ψ

• hits in RPCs

• cluster in ECL

• Remove positively tagged background modes: J/ψK+ , J/ψK* , etc.

• Plot

LKJB Ψ→ /0

**/

*LKJB ppp += Ψ

Page 43: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

0LK Detection

Θ

LKP

missP

∑± =

−=hi

iS PPP,

4missγ

Inclusive “KL’s”

Page 44: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

B→J/ΨKL Reconstruction

**/

*LKJB ppp += Ψ

61% signal purity

Page 45: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

CP Mode Summary

Page 46: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Flavor TaggingWe need to know the flavor of the spectator B0.

• Track level tags

• High momentum leptons

• Medium momentum K±

• High-momentum π± (from e.g., )

• Low-momentum π± (from D*’s).

• Need to take into account multiple tags and correlations.

+−→ π(*)0 DB

Page 47: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Flavor Tagging

yreliabilit tag 10 ;1 ⇔<<±= rq

Page 48: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Flavor Tagging

rq ⋅

Data

Monte Carlo

ν±→ "#*0 DB

Page 49: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Flavor TaggingTwo measures of tagging performance:

• ε = efficiency

• w = wrong-tag fraction

Amplitude of mixing oscillation depends on w

)21( w−01.027.0eff ±=ε

Page 50: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Vertexing

0B

+µ−µ

0B

+µtag

CP

z∆

0D−e +e

0K

Ψ/J

Reality

Cartoon

The B lifetime is of the same order as the vertex resolution, so the effect is quite subtle.

Page 51: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Vertexing

• Common track requirements– # of associated SVD hits > 2– Use run-dependent IP

• For CP-side, use J/ψ"l+l- tracks– Reject poorly fit events.

• For Tag-side, use tracks with:– |δz|<1.8mm, |σz|<500 µm, |δr|<500 µm– Iterate: discard worst track until fit is acceptable.

• Require |zCP - ztag|<2 mm (≈10τB)

Page 52: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Test of Vertex Resolution0*0 / KJB Ψ→

Page 53: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Fit to Lifetime

ν"*DB →

(ps) t∆

ps 03.064.1

ps 02.055.10

±=

±=

−B

B

ττ

Page 54: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Fitting

)()'( sigsig tRttPLi ∆⊗∆−∆= )1( bgf−×

bgbgbg )()'( ftRttP ×∆⊗∆−∆+

[ ])sin(2sin)21(12

)( 1

/

sig tmwqetP fB

t B

∆∆−−=∆∆−

ϕητ

τSignal

)()1(2

)(/

bkg tfeftPbg

t bg

∆−+=∆∆−

δτ τ

τ

τ Background

Response function

Page 55: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Fitting

Page 56: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

The Data

The first order effect is a mean shift between positively and negatively tagged samples.

Page 57: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

The Fitted Result

06.014.099.02sin 1 ±±=ϕ

PRL 87, 091802 (2001)

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November 2001 CP Violation at Belle

Sources of Systematic Error

±±±±0.06Total

±±±±0.01∆∆∆∆md and ττττB0 errors

±±±±0.01Background shapes

±±±±0.02KL background fraction

±±±±0.02Resolution function

±±±±0.03Flavor tagging

±±±±0.04Vertex algorithm

Page 59: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Time-Dependent AsymmetryOne can plot the excess/deficit on a bin-by-bin basis.

First we start with a non-CP sample to look for false asymmetries.

Page 60: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Subsample Dependence

Page 61: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Subsample Dependence

Page 62: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Comparison to other sin2ϕ1Measurements

It looks like CDF had it right!

Page 63: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Comparison to Other CKM Results

BaBar

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November 2001 CP Violation at Belle

Future Prospects

Oide

2.0)2(sin 2 ≈φδ

Page 65: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Conclusions• CP violation in the B system has been observed at the >6σ level.

• Our data are consistent with the SM.

•The KEKB accelerator is working very well and continues to improve.

• There will be lots of good physics to come.

06.014.099.02sin 1 ±±=ϕ

Page 66: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Additional Slides

Page 67: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Two Pseudoscalar Modes

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November 2001 CP Violation at Belle

What if |λ|≠1 ?

If |λ| is allowed to float, (i.e. a cos(Δm t) term)

14.099.02sin 1 ±=φThe CPV asymmetry is unchanged.

09.003.1 ±=λ

In general we have

Note: if |λ|≠1, then the gold-plated mode isn’t really gold plated.

Page 69: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

KL Details

•Two classes: KLM+ECL and ECL only(397 and 172 entries, respectively)Fitted yield is 346 events.• Background composition: 71% non-CP modes.The remainder is ψKLπ0(13%), ψKs(10%) whichare both CP=-1 and 5%(ψK, χc1Ks, ψπ0) whichare CP=+1.• pB

* background shape is used to find bkg level.

Page 70: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

−+→ ""(*)KB613.0 40.0

0.14- 32.0 10)99.0()(

−++−

−+

×=→ µµKBB

CL 90% 101.3)(

6

*

−+

×<→ µµKBB

CL 90% 103.1)(

6−

−+

×<→ eeKBB

CL 90% 106.5)(

6

*

−+

×<→ eeKBB

Page 71: Observation of CP Violation at Belle - Princeton …marlow/talks/bnl/bnl2.pdfNovember 2001 CP Violation at Belle Talk Outline • Introduction/Review (with apologies to the experts)

November 2001 CP Violation at Belle

Particle ID (dE/dx, ToF, & Aerogel)