CLEOC/BESIII—New Frontiers of -C Physics

I . CLEOC/CESRC and BESIII/BEPCIIII. Physics Over View III. Current StatusVI. Suggestions to BESIIIV. Summary

Z.G. Zhao University of Michigan, Ann Arbor, MI, USA

IHEP of CAS, Beijing, China

Current Operating e+e- Colliders

-c B

1

10

100

1000

10000

0 2 4 6 8 10 12 14

Ecm(GeV)

VEPP-2M

DAFNE

VEPP-2000

BEPC

BEPCII

CESR-C

KEKB

PEPII

VEPP-4M

CESR

Factory

Pea

k L

um

inos

ity

(1/1

030 c

m-2s-1

)

• Modify CESR for low-energy operationCESR-C; • Add wigglers for transverse cooling

• State of art detector, well understood • Replace silicon strip tracker with 6 layer inner drift chamber

1.5 T now,... 1.0T later

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

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

BEPC II BEPC II — — Double Ring Double Ring

IP

e -

RFRF SR

e+

Ecm=2~5.16 GeV

Luminosity~1033 cm-2s-1

(optimized at 3.68 GeV)

• Be competitive to CLEOC

• Almost a completely new detector

CDC: xy=50 m

MDC: xy=130 mp/p = 0.5% @1GeVdE/dx=6% @mip

EMCAL:E/E = 2.5% @1GeVz = 0.5 cm/E

TOF:T = 80 ps Barrel 100 ps Endcap

Magnet: - 0.4-0.5 T existing BESII magnet - 1 T Super conducting magnet

Muon ID: 9 layer RPC

Trigger:Tracks & ShowersPipelined; Latency = 2.4s

Data Acquisition:Event size = 12kBThruput ~50 MB/s

Physics Features in -c Energy Region

CESRC

BEPCII

(3770)

Physics Features in -c Energy Region

• Transition between smooth and resonances, perturbative and non-perturbative QCD

• Rich of resonances, charmonium and charmed mesons.

• New type of hadronic matter are predicted in the region, e.g. glueball and hybrid

• Threshold characteristics, large , low multiplicity, pure initial state, S/B optimum

A Typical Hadronic Event in CLEOIII/BESII

CLEO Hadronic events from BESIIR scan

Key Issues in Particle PhysicsVerify the SM The test of the SM has been dominating exp. HEP for about three decades.

Establish and test strong-coupled, nonperturbative quantum field theories Still the foremost challenge in modern physics The effects of the strong interactions non PQCD permeate every experimental measurement involving quarks and are an obstacle in almost every attempt to extract precision electroweak physics from data.

Probe new physics beyond the SM

It’s of profound importance to • systematically study the weak interactions that mix quark and

lepton flavor• complete understand QCD

Precision data is badly needed to enable a comprehensive mastery over non PQCD and to calibrate and validate the theoretical technology

CKM and LQCD

CKM Matrix

• CKM, fundamental parameters in nature that reflect the flavor and generation mixing, is induced by weak interaction. • Cannot be predicted within the SM and must be determined by experiment.

• Charm decays is a unique laboratory to determine directly Vcd and Vcs, indirectly Vub and contribute to Vcb.

D decay

Mixing

b

s

d

b

s

d

tb tstd

cb cs cd

ubus ud

V V V

V V V

V V V

'

'

'

% 29 % 39 % 36

% 5 % 12 % 7

% 25 % 1.0 % 0.1

B decay

Lattice QCD

• LQCD is the only compete definition of QCD. It includes both perturbative and non perturbative QCD.

• LQCD is not a model.

- The only parameters are s and the quark masses.

- Relates B/D physics to Y/ physics and to glueball

physics to …

• Predict to ~15% accuracy for a wide range of masses (include glueball and hybrid), decay constants, form factors for many conventional hadrons.

• The challenge for LQCD is to demonstrate reliability at the level of a few percent accuracy require wide range of highly precision experimental data

LQCD Predictions for Glueball Masses

Lowest Lying States:

Scalar 0++, M ~ 1.6 GeV

Tensor 2++, M ~2.3 GeVPseudoscalar, M ~ 2.5 GeV

QCD is not understood until we understand gluonic degree of freedom in the spectrum,glueballs and hybrids.

The CLEOC Program

Act I (2003): (3770) 3 fb-1 30M events, 6M tagged D decays

Act II (2004): ~ 4100 3 fb-1

1.5M DsDs, 0.3M tagged Ds decays

Act III (2005): (3100) 1 fb-1

1 billion J/ decays

Focused data samples to collect and clear physics goals to reach.

Precision Standard Model Tests

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

• fD+ and fDs at ~2% level

• Semileptonic decay form-factors (few %

accuracy)

Contribute to CKM Measurements

Absolute Branching Ratios

Decay Mode PDG2000 CLEOC (Br/Br %) (Br/Br %)D0 K2.4 0.5D+ K7.2 1.5Ds 25 1.9

Set absolute scale for all heavy quarkmeasurement

fD+ and fDs

• LQCD can predicts fB/fD and fBs/fDs. Measure fD, fDs

give fB and fBs, thus determine Vt d and Vts

• Similarly measure fD/fDs checks fB /fBs

CLEOC Expected Precision in Decay Constants

Decay Mode Decay Constant fDq/fDq (%)

D+ + fD 2.3

Ds+ + fDs 1.7

Ds+ + fDs 1.6

Semileptonic Form Factors

Semileptonic decay severe as excellent laboratory to study

both weak and strong interaction

e.g. D+ Kl

Decay Mode / CKM Element CKM Precision

D0 K-e+ 1.2% |Vcs| 1.6%D0 -e+ 1.5% |Vcs| 1.7%

2232

2

2

2)(

24qfPV

G

dq

dKcs

F

Weak physics

Strong physics

How Much CLEOC Can Improve CKM

% 29 % 39 % 36

% 5 % 12 % 7

% 25 % 1.0 % 0.1 Present

% 15 % 5 % 5

3% % 1 % 1

% 5 % 1 % 0.1

After CLEOC

Other Interesting Topics

Test of the SM and QCD in Continuum

• R scan 2-5 GeV (2~3%)

Evaluating QED, a’ mHiggs, high precision test of SM, hunting for new physics beyond the SM; structures of high mass region

• Large hadronic events sample at point (2-3GeV) - Multiplicity: second binomial momentum

R2 [nch(nch-1)/nch2] = 11[1-cs(s)]/8 NLQCD

- =-ln(p/s) distribution for charged particles MLLA, LPHD - Hadronic events shape: thrust, transverse moment distribution pQCD, power correction - (e+e- 2/4 /K); e+e- /K+X; Polarized parton density, S/U universality; quark and glue

fragmentation (combine with J/ data)

• Charmed baryons pQCD, string fragmentation, HQE and duality

Relative Uncertainty Contribution to a and (Mz

2) without BES R Data

Relative Contribution in Magnitude and Uncertainty

BESIII,CLEOCCMD,SND

KROE

CLEO

Second Order Momentum

Peak Position of

MeanThrust S/U Universality

J/ and (2S) Decays

J/ decays• Search for new forms of matter

- Glueballs: (1440), f0(1370), f0(1500), f(1700), fJ(2000)

- Exotic mesons: 1(1400), 1(1600), • Study of excited baryonic states (N*, *, *, *... )(2S) decays• Search for missing or unconfirmed states: 1P1, c

’

• Measure hadronic branching fraction ( puzzle) • Measure radiative transition rate• Study of cJ states

Best laboratory to elucidate a tricky situation; uniqueopportunity for QCD studies and new level of understanding

• Lower limit on m at sub 10 MeV level

• Determination of m 0.1 MeV

• Precision measurement of key Br. (,0)

• Measure Michel parameters

• Direct search for non-SM physics

New Study of the Lepton

• D0D0bar mixing

• CP violation in , J/, (2S) decays

• Lepton flavor violating processes

e.g. J/’, =e, , • Rare decays

--X, e-G, -……. J/DX

Taking advantage of threshold production,

much high statistics and low background

Searches and New Physics

Why CLEOC in B Factory Era

• Some important measurements at B’s are limited by systematical uncertainty

• CLEOC enjoys threshold production, large production cross section, low multiplicity, low BG, high S/B. But limited by statistics

Why BESIII in CLEOC Era?

CESRC

BEPCII

CLEOC: 2003: (3770) -- 3 fb-1; 30 M 2004: 4100 -- 3 fb-1; 1.5M DsDs 2005: (3100) -- 1 fb-1; 1 Billion J/

BESIII

• Three years CLEOC program does not cover all the interesting physics in c energy region

- 2-3 GeV, 2-3% R scan in 2-5 GeV

- physics of and (2S)

- Charmed baryon

• Need higher statistics for searches (glueball, exotica), rare decay, D0-D0bar mixing, CP and further improve the precision measurements.

• New discoveries needs to be confirmed or continued. New type of matters, need high statistics to study it’s properties.

Why BESIII in CLEOC Era?

Is BESIII Worth Doing?

YES

if L~1033 cm-2s-1 and BESIII is competitive to CLEC, and the commissioning is not too late

Otherwise NOT really

Possible Side Product

• Cosmic ray experiment

e.g. low energy (E<10 GeV) spectrum. Important for SupperK experiment

L3CBESIII-C (cosmic exp.)

Suggestions to BESIII/BEPCII

• BEPCII: L~1033 cm-2s-1; BESIII compatible to CLEOC• Learn experiences and lessons from the other successful

labs. Utilize ONLY mature technology.• Don’t use highest version of hardware and software.• Build a workable, reliable system has the highest priority.

Don’t try to design fancy systems which is difficult for one to learn and use.

• Set up an active international collaboration. A team that can committed and devoted to the project is essential

• Select or train qualified experts in charge of each sub-system is of profound importance for the success of the project

Suggestions to BESIII/BEPCII

• Prototype, R&D work should be done as early as possible

• Additional attention should be paid to

- overall detector/ machine integration

- alignment and monitoring

- IR region

- trigger

- detector simulation, database, computing and network

- better thermo isolation in detector hall (~12-28 0C)

- better gas supply system (shorten the transportation

distance, less T)

CLEOC/CESRC Status

• CESR/CLEO Program Advisory Committee Sept 28 2001 Endorsed CLEO-c

• Proposal submission to NSF (October 15,2001)

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

• Expect approval in Summer of 2002

• Wiggler prototype test successfully in vertical cryostat; now being installed in its horizontal cryostat. Will be put into CESR in July

• Start building six layers CDC • Cost $3.5 M

Status of BEPII/BESIII

• Feasibility Study Report of BEPC II has been submitted to the funding agency.

• Technical Design Report of BEPC II to be submitted soon.

• Construction expected d to be started in 2003 and commissioning in 2007.

• Cost $75 M (~1/3 for BESIII)

CLEOC/CESRC:

Wisely seizes the great opportunity; perfectly fills the gas in the

frontier of weak and strong interactions

BESIII/BEPCII:

Nature extension. Will be a unique frontier of c physics for a

decade after CLEOC.

Interesting Schedule of CLEOC/BESIII

1984 1988 2000 2005 2010

Year

CLEOC phys. run ?

BESII BESIII Construction

BESIII

Engineer & phys. run

MARKIII

Typical Peak Luminosity of CESR-C, BEPC and BEPCII

L(BEPCII) 3 L(CESR-C) 50L(BEPC)

1

10

100

1000

10000

3.1 3.77 4.1

Ecm(GeV)

CESR-C

BEPCII

BEPC

Pea

k L

umin

osity

(1

/1030

cm

-2s-1

)

Typical Dada Samples Proposed

0.001

0.01

0.1

1

10

100

1000

10000

J/psi psi(2S) psi(3770) Ds Pairs(4100)

Psi Family

Nu

mb

er o

f E

ven

t (M

illio

n)

MARKIII

BESI/II

CLEOC

BESIII

Additional Data for other physic topics

• Charm baryons at threshold, e.g. +- pairs at threshold

• R scan in 2-5 GeV; large hadronic event sample in 2-3 GeV

cc

Summary

• Physics in tau-charm energy region is sill very rich in the B’s era.

• CLEOC/CESRC, a smart decision that seizes great physics opportunities, is opening a new era of understanding weak and strong interaction.

• BESIII/BEPCII, an nature extension of the only high energy physics base in China, will continue BESII and CLEOC’s mission to deepen the understanding of weak and strong physics, play a unique role in the precision test of SM, QCD and search for new physics in c sector.

Tanks to

Maury and CLEOC collaboration for the

Information about CERSC/CLEOC

Weiguo Li and BES collaboration for the

information about BESIII/BEPCII

Fred for many useful discussion about BES’s

future