CLEO-c and CESR-c:

A New Frontier of Electroweak

And QCD Physics

Kamal Benslama

Seminar at the University of Montreal

November 14, 2002

CLEO-cCLEO-c CESR-cCESR-c

DoDo, DoK-+

K-

K+

+

The CLEO Collaboration

AlbanyCaltechCMUCornellFloridaHarvardIllinoisKansasMinnesotaOhio StateOklahomaPurdueRochesterSLACSMUUCSDUCSBSyracuseVanderbiltWayne State

• Membership: • ~20 Institutions• ~155 physicists• ~1/2 DOE, 1/2 NSF• Currently expanding…

• Publication history 1980-• ~320 papers• diverse physics:

CESR

The CESR Storage Ring

The Storage Ring

Symmetric e+e- accelerator at or near (4S)(PB ~ 300 MeV/ c)

On the (4S):e+e- (4S) BB ( ~ 1 nb) e+e- qq, (q = u, d, c, s) ( ~ 3 nb)

1/ 3 running at OFF (4S) for continuum bkg subtraction

CLEO III collectedON: 6.9 fb-1 OFF: 2.3 fb-1

--

CESR and CLEO

What is CESR-c and CLEO-c ?

• Modify for low-energy operation: add wigglers for transverse cooling

• Expected machine performance:

• Ebeam ~ 1.2 MeV at J/

Ecm L (1032 cm-2 s-1)

3.1 GeV 2.0

3.77 GeV 3.0

4.1 GeV 3.6One day scan of the ’:(1/29/02)

1.5 T now,... 1.0T later

93% of 4p/p = 0.35% @1GeVdE/dx: 5.7% @minI

93% of 4E/E = 2% @1GeV

= 4% @100MeV

83% of 4% Kaon ID with

0.2% fake @0.9GeV

85% of 4For p>1 GeV

Trigger: Tracks & ShowersPipelinedLatency = 2.5s

Data Acquisition:Event size = 25kBThruput < 6MB/s

CLEO III Detector CLEO-c Detector

CleoIII Tracking

Silicon (r = 2 - 12 cm) 4 Layers, double sided Suffering from rad damage

Drift Chamber (DR) (r = 12 – 82 cm) 47 anode layers, 9796 cells Inner part axial, outer part all stereo

Central Drift Chamber

• DK mass resolution ~ 5.5 MeV• Ks mass resolution ~ 3.1 MeV• p/p = 0.35% @1GeV• dE/dx: 5.7% @minI

Average hit resolution 85Sweet spot ~ 55-65

dE/dx in the Drift Chamber

•CleoIII dE/dx vs Momentum showing the , K and p bands.

•The K/ separation from dE/dx, in standard deviations.

Inner Tracking (2 < r < 12cm)

• Now: 4 Layer Silicon Detector• Double sided wafers, • 125000 channels• 1.6% X0 thickness• early radiation damage:

Layers 1 & 2 r eff

• Proposed: 6 layer drift chamber• all stereo ( 10-150 tilt)• 300 channels: smaller evt size• 1.1% inner wall + 0.1% gas• improves p/p (less material)

• worsens z0 (stereo)•

preserves mass resolution• no effect on pattern recognition• build from spare parts

Silicon Radiation Damage(

rad)

• Efficiency losses exhibit wafer geometry, not detector geometry. • rphi side only. Z side so far shows no eff loss.

Wire vertex Chamber

RICH Detector

Performance with Bhabhas (only RICH tracking):

single resolution N resolution/track

Flat radiator 14.0 mrad 10.2 5.3 mrad

Sawtooth radiator 12.2 mrad 12.0 4.2 mrad

Thinnest (19 cm) <0.12% X0

Proximity Focusing

Solid Radiator (LiF)

45o saw tooth outer face (40%)

Rest flat radiator

15.7 cm N Expansion Gap

MWPC photon detector

Photosensitive gas = TEA (Triethylamine)abs=0.5 mm, <165 nm

3 K/ separation at 2.65 GeV/c

RICH

Cherenkov Images

Flat radiators

Sawtooth

The RICH Smiles

e+e- e+e-

PID using the RICH

#

1

#

1

)|(

)|(

ibackisignal

ibackKisignalK

PPL

PPL

•Likelihoods are defined as

where

- CB line shape (Gaussian with power law tail on the high side)

- constant

2K2

= -2log(LK/L)

•Likelihood method folds in photon count and Cherenkov angle measurement together

signalP

backP

Efficiency vs fakes study

•cut on 2K2

•fit m(D0)

2K 2

x2K 2

K

K

mD0(GeV)/c2

Nu

mb

er o

f ev

ents

CsI Calorimeter

•93% solid angle coverage - uniform resolution in barrel & E.C.

E/E = 4% @ 100 MeV

2% @ 1 GeV

•~5.5 MeV 0 mass resolution

Typical Hadronic Event

(From online event display)

Look What RICH did to our Data !

Signal characteristics:

Two stiff back-to-back particles

Simple, robust analysis.

Statistics limited, not systematics

Backgrounds:

Entirely from “continuum”

Continuum background characterized by event shape variables

CLEOIII Rare B Analysis

Continuum occasionally produces high momentum, back-to-back, 48%

35%K , 17%KK.

Roughly 25% from , 75% from , ,

Primary handle is in global event shape characteristics

π π

πddcc uu ss

Signal Continuum

Spherical event 2-jets Shape Structure

Continuum Background

Analyses Strategy

Study backgrounds (using Monte Carlo and OFF-resonance data)

Reconstructions variables

Maximum likelihood fit

PS: I would prefer Neural Network

Monte Carlo Experiments:

Study possible biases

Apply the fit to data

sign

al

cont

inuu

m

Energy difference Beam constrained mass

~ 2.5 MeV (3.0 MeV if 0 )Resolution is mode dependent, but generally ~ 20-25 MeV(2 worse if 0 )

2 2| |p beam BE M beam

BiE E E daughters

dE/dx RICH

Reconstruction Variables

Signal is isotropic, continuum is jettyUse shape variables

Sphericity angleR2 (Fox Wolfram moment)Momentum flow in nine cones around the sphericity axis

Combine the variables in a Fisher discriminant

Reconstruction Variables

bNsN and are the yields to be determined

PDF shapes for signal are determined from MC

PDF shapes for continuum are determined from OFF-resonance data

Maximum Likelihood Method

Fit variables:

Fit component fractions:

Outputs:

plus background, at the maximum of the Likelihood function.

Efficiency: Use of Maximum Likelihood fit doubles the efficiency of the analysis compared to a normal counting analysis

Systematics: All shapes are systematically varied to study effects.

Correlations: typically at few % level, except

- where kinematics leads to ~ 20% correlation.

BM ΔE F2dx

dE

Bcosθ

Kπf

ππN

1dx

dE

ππf KKf

KπN KKN

ΔE BM

Maximum Likelihood Fit

3.18.186.182.29 8.26.2

0.35.44.31.4

1.74.6

Yield BR(BK)(x10-6)BK CLEOIII CLEO(1999)

Good agreement: between CLEOIII & CLEO II & with BaBar/Belle.

How well does CLEO III work?1st results from CLEO III data at Lepton-

photon 2001

FINAL Results VERY Soon

The CLEO-c Program

2002

2003

2004

2005

Prologue: Upsilons ~1-2 fb-1 ea.Y(1S) ,Y(2S), Y(3S)…Spectroscopy, Matrix Elements, ee

10-20 times existing world’s data

Act I: (3770) -- 3 fb-1

30M events, 6M tagged D decays(310 times MARK III)

Act II: √s ~ 4100 -- 3 fb-1

1.5M DsDs, 0.3M tagged Ds decays(480 times MARK III, 130 times BES II )

Act III: (3100) -- 1 fb-1

1 Billion J/ decays(170 times MARK III20 times BES II)

•Charm events produced at threshold are extremely clean•Large , low multiplicity

•Pure initial state: no

fragmentation•Signal/Background is optimum at threshold

•Double tag events are pristine–These events are key to making absolute branching fraction measurements

•Neutrino reconstruction is clean•Quantum coherence aids D mixing and CP violation studies

Why run on threshold Resonances ?

A typical Y(4S) event:

Tagging Technique

• Pure DD or DsDs production Many high branching ratios (~1-10%) High reconstruction eff Two chances

high net efficiency ~20% !

D K tag. S/B ~ 5000

Ds KK tag. S/B ~ 100

Beam constrained mass

6M D tags300K Ds tags6M D tags300K Ds tags

• We expect great advances in flavor and electroweak physics during the next decade:– Tevatron (CDF, D0, BTeV,CKM).– B-Factories (BaBar, Belle).– LHC (CMS, ATLAS, LHC-b).– Linear Collider (?).

• What could CLEO-c possibly have to offer this program?

Why CLEO-c ? Why Now ?Why CLEO-c ? Why Now ?

To score nice goals weAbsolutely need an excellent player who can make the Perfect passes at the perfect time

CLEO-c

Precision Standard Model Tests

fD+ and fDs at ~2% level.

Absolute hadronic charm branching ratios with 1-2% errors.

Semileptonic decay form-factors (few % accuracy).

Contribution to CKM Measurements

Absolute Branching Ratios

~ Zero background in hadronic modes

Decay Mode PDG2000 CLEOc(B/B %) (B/B %)

D0 K 2.4 0.5D+ K 7.2 1.5Ds 25 1.9

Set absolute scale for all heavy quark meas.

The importance of absolute Charm BRs

Stat: 3.1% Sys 4.3% theory 4.6%Dominant Sys: slow, form factors

& B(DK) dB/B=1.3%

Vcb from zero recoil in B D* +

CLEO LP01

310)1.20.24.14.46( cbV

Decay Constants: |fD|2 |VCKM|2

Ds

D

f Ds

f D s

2.1%

f D

f D

2.6%KL

(Now: ±35%)

(Now: ±100%)

Br(Ds

Importance of measuring fD & fDs: Vtd & Vts

1

2

3

2

1

108.820050.0

tdBB

d

V

MeV

fBpsM dd

d

d

BB

BB

d

d

Bf

Bf

M

M )()(5.0

)(

1.8% ~15%

Lattice predicts fB/fD & fBs/fDs with small errorsif precision measurements of fD & fDs existed (they do not)could substitute in above ratios to obtain precision estimates of fB & fBs and hence precision determinations of Vtd and Vts Similarly fD/fDs checks fB/fBs

(lattice)22

ts

td

BB

BB

s

d

V

V

fB

fB

M

M

ss

dd

i1 i

1

~5% (lattice)

COMPARISON

0

5

10

15

20

25

30

Error

(%)

Df

)KD(Br

)D(BrS

)KD(Br 0

BaBar 400 fb-1

Current

Comparison between B factories & CLEO-C

Systematics & Background limited

CLEO-c 3 fb-1

Statistics limited

abcdefghi

f Ds

|f(q2)|2

|VCKM|2

Absolute magnitude & shape of form factors is a great test of theory.

b

c

u

d

HQET

l

l

1) Measure D form factor in Dl (CLEO-c): Calibrate LQCD to 1%.2) Extract Vub at BaBar/Belle using calibrated LQCD calc. of B form factor.

3) Precise (5%) Vub is a vital CKM cross check of sin2.

4) Absolute rate gives direct measurements of Vcd and Vcs.

B

D

i.e.

Semileptonic Form Factors.Semileptonic Form Factors.

2232

2

2

2)(

24qfPV

G

dq

dKcs

F

Semileptonic Decays |VCKM|2 |f(q2)|2

Decay Mode PDG2000 CLEOc(B/B %) (B/B %)

D0 Kl 5 1.6D0 l 16 1.7

D+ l 48 1.8Ds l 25 2.8

Plus vector modes...

U = Emiss - Pmiss

LowBkg!

e

eD

eKD

eKD

eD

eD

eKD

eKD

eD

eD

eKD

eKD

c

s

s

s

:12

:11

:10

:9

:8

:7

:6

:5

:4

:3

:2

:1

0*

0

0

0

_0*

_0

0

0

*0

0

Semileptonic dB/B, Vcd, & VcsSemileptonic dB/B, Vcd, & Vcs

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8 9 10 11 12

Decay modes

Err

or (%

)

CLEOc

PDG

Vcs /Vcs = 1.6% (now: 11%) Vcd /Vcd = 1.7% (now: 7%)

eKD0

eD0

Use CLEO-c validated lattice + B factoryBlv for ultra precise Vub

D0 l

D0 Kl

How can CLEO-c Contribute to CKM Measurements ?

An illustration using a variant of the 95% Scan method.

Allowed regions of the - plane using: • current experimental results and• conservative theoritical uncertainties

Allowed regions of the - plane using:

• current experimental results and• theoritical uncertainties of O(1%)•2% decay constants and 3% semileptonic form factors

CLEO-c: Probes of new Physics

Mixing sensitivity at the 1% level.

CP violation sensitivity at the 1-2% level.

• Rare Decays. Sensitivity: 10-6

0D

0D

K-

K-

0D

0D

K+

K-

Ratio of Rates:

Charm MixingCharm Mixing

x = /y = /2

To 1st order, where

e+e ” D0D0

NO DCSD

Quantum coherence

At the (3770)

e+ e

0D

0D

+

K+

e+e ” D0D0

JPC = 1

i.e. CP+

Suppose both D0’s decay to CP eigestates f1 and f2: These can NOT have the same CP :

CP ViolationCP Violation

Observing this is evidence of CP

Ex: )π)(πK(K

CP(f1 f2) = CP(f1) CP(f2) (-1)l = CP

+ (since l = 1)

Compare to B Factories

CLEO-C BaBar Current2-4fb-1 400 fb-1 Knowledge

f_D |Vcd| 1.5-2% 10-20% n.a.

f_Ds |Vcs| <1% 5-10% 19%

Br(D+ -> ) 1.5% 3-5% 7%

Br(Ds -> ) 2-3% 5-10% 25%

Br(D->l) 1.4% 3% 18%

Br(c -> p) 6% 5-15% 26%

A(CP) ~1% ~1% 3-9%

x'(mix) 0.01 0.01 0.03

Systematics & background limited.Statistics limited.

• and Spectroscopy–Masses, spin fine structure

–Leptonic widths for S-states.

–EM transition form factors•run on resonances winter ’01-summer’02

•~ 4 fb-1 total

Uncover new states of matter

Glueballs G=|gg

Hybrids H=|gqq

Requires detailed understanding of ordinary hadron spectrum in 1.5-2.5 GeV mass range.

Study fundamentalstates of the theory

Calibrate and testtheoretical tech.

Probing QCD

•Gluons carry color charge: should bind! • But, like Elvis, glueballs have been sighted too many times without confirmation....

• CLEO-c: find it or debunk it!

huge data set modern detector 95% solid angle coverage

• Radiative decays are ideal glue factory:

Gluonic Matter

X

c

c̄

• CLEO-c: 109 J/ ~60M J/ X• Partial Wave analysis • Absolute BF’s: ,KK,pp,,…

1• perfect initial state• perfect tag• glue pair in color isosinglet

The dubious life of the fJ(2220)(A case study)

Now you see it…

BES (1996)

MARKIII(1986)

L31997

Now you don’t…

Crystal barrel: pp??LEAR1998

OPAL1998

L3 Signal

2 3

MKK

2 3

… or do you?

… or don’t you?

fJ(2220) in CLEO-c?

fJ(2220) in CLEO-c?

Two Photon Data: fJ2220 – CLEO II: B fJ /KSKS < 2.5(1.3) eV

– CLEO III: sub-eV sensitivity

Upsilonium Data: (1S): Tens of events

5000–

850032pp

530023KSKS

1860046K+K-

1300018

3200074

CLEO-CBES

CLEO-c has corroborating checks:

2

3

Inclusive Spectrum J/ X

10-4 sensitivity for narrow resonanceEg: ~25% efficient for fJ(2220)

Suppress hadronic bkg: J/X

Additional topics

• ’ spectroscopy (10 8 decays) ’chc…

• at threshold (0.25 fb-1)

• measure mto ± 0.1 MeV• heavy lepton, exotics searches

• cc at threshold (1 fb-1)• calibrate absolute BR(cpK)

• R=(e+e- hadrons)/(e+e- +-)• spot checks

If timepermits

Likely tobe addedto runplan

-

The CLEO-c Program: Summary

• Huge data set• 20-500 times bigger than previous experiment

• Modern and understood detector•Experienced Collaboration

• Powerful physics case• Precision flavor physics - • Nonperturbative QCD - • Probe for New Physics

• Very small and well-controlled backgrounds •Very small and well-understood systematic errors

• A large number of and wide variety of precision measurements to challenge and validate theory

CLEO-c Physics Impact

•CLEO-C workshop (May 2001) : successful ~120 participants, 60 non-CLEO•Snowmass working groups E2/P2/P5 : acclaimed CLEO-c• HEPAP endorsed CLEO-c

•CESR/CLEO Program Advisory Committee Sept 28 Endorsed CLEO-c•Proposal submission to NSF was on October 15,2001

•Site visit on Jan/Feb 2002: Endorsed CLEO-c

•Science Board March 2002, • Expect approval shortly thereafter•See http://www.lns.cornell.edu/CLEO/CLEO-C/ for project description

Invitation

If interested in CLEO-c program you are morethan welcome to join my ex-colleagues. They have room for you !

More information is available in CLEO Web page: www.lns.cornell.edu/CLEO/CLEO-c

Contact person: spoke@mail.lns.cornell.edu

CLEO-cCLEO-cCESR-cCESR-c

Glueball Spectrum