X. C. Lou, Snowmass 20011 Charm Physics Potentials at B-factories XinChou Lou, University of Texas at Dallas Introduction Physics Topics: branching fractions,

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X. C. Lou, Snowmass 2001 1

Charm Physics Potentials at B-factories

XinChou Lou, University of Texas at Dallas

• Introduction

• Physics Topics: branching fractions, leptonic decays, mixing

• Extrapolations from CLEO-B• Initial State Radiation Production of Charm

Events at B-Factories• Measurements with ISR Charm at B-factories

• Summary

0 0D D


Introduction

• BaBar projection 32 fb-1 by end of August 2001

~400 fb-1 by end of 2004

• CLEO-c plan Data-taking in Spring 2003 around charm thresholds, a few fb-1

Physics soon after

• Super B-factory after 2010?

Look at physics of BaBar and CLEO-c in near term Super B-factory longer term


CLEO-B Extrapolations

0 * *

0 * *

0

0

( )

( )

s

s

s tag

tag s

B D D

B D D

N

ND

D D

D

• Leptonic Ds decays, fDs 4.8 fb-1

CLEO, PRD 58,032002(1998)

• Method

current fDs=(280 29 28 34) MeV

(7stat10sys 12B)%

with 400 fb-1 (<1 (3-6) 2)% (4-7)%

main sys. error: PID, tracking

Model Dependent

• 2.5 fb-1 clns95-1387

current (21.5stat13.4sys)%=24%

main sys. errors: random and eff.BR

with 400 fb-1 (1.73)%3.5%

main sys. Error: tracking

Model Dependent

( )sB D

*

*

( )

( )

s s

s s

N D D

N D D



• 4.7 fb-1

CLEO, PRD 62,072005(2000)

• methods: , B-decays, SL/Lifetime

current B=(5.0 0.5 0.12)%

(10stat15 12 8 8 5)%

main sys. errors: p tag, modeling, Dp bkg,

c/D spectra, c /D ID

with 400 fb-1 (1.1 (2-5) 2)% (3-6)%

main sys. error: same as above, tracking

Model Dependent

• 1.79 fb-1

CLEO PRL 72, 2328 (1994)

continuum data

with measured

current (3.25.4 5.0)%8.6%

main sys. errors: R+, eff., B(D0K)

with 400 fb-1 (21.5 1.5)%3%

main errors: R+, eff., B(D0K)

Model Dependent

( )B D K

0

0

*

*

( )

( )K

KN D D

N D D

* 0

* 02.21 0.07

( )( )D D

RD D

BB

( )cB pK

|

|

([ ] )( )

cN p DN p D



• Mixing 9 fb-1 CLEO Conf 01-1

Standard Model 10-8, Beyond SM 10-(3-4)

Method

current best limits (5-9)10-3 (E791, ALEPH)

Sentivity with 400 fb-1 data: for rmix (BaBar Phys. Book)

0 0D D

0

0

*

*

( )(

( ( )

)

)K

KN D D

N D D

t

t

Mode rD

(10-3)

rW

(10-3)

N0

(106)

Sensivity

(10-4)

K 7.2 1.5 2.6 1.3

K 2.5 1.5 3.1 0.8

K0 2.8 1.5 5.8 0.6

0

45

D Wr reN


The ISR Method at B-factories

M. Benayoun et. al.

Spectroscopy at B-factories Using

Hard Photon Emission

Modern Phys. Lett. A Vol. 14,

No. 37, 2605-2614 (1999)

form factors, R scan, Upsilon states

X. C. Lou and W. Dunwoodie

Physics with ISR Events Produced

at B-factory Experiments

Presented at Hadron 99, Sept, 1999

Nucl. Phys. A675, 253 (2000)

charmed hadrons, charmonia, exotics


Production of Charm near Thresholds via ISR

• ISR production cross section

ISR = 0

1 f(s,k)(s´)dk J. P. Alexander et. al. SLAC-PUB-450

• Narrow resonance approximation

(s´) = (3/s´) ee0 .

( s´-MR)2+02/4

Example: e+e- (2S) ISR=13.3 1.1 pb

provides a way to determine leptonic width ee


Observation of ISR (2S) signal by BABAR (8.9fb-1)

208 ±15 events

M()-M() (GeV) M() (GeV)

events

Momentum (GeV) Fitted Momentum (GeV)

DPF 2000


Estimate of ISR Charm Rates

Production interact.

(GeV)

fraction of sampling fun.

cross-section(Coupled-channel

model)

produced events in 400

fb-1 of data (1000)

(all) 3.94 4.33 0.00167 ~1 nb ~670

(charged + neutral) 4.0 4.6 0.00273 ~6 nb ~6,000

4.57 5.09 0.00284 ~0.4 nb ~450

J/(2S)

~3.096

~3.767

~38 pb

~13 pb

15,200

5,200

* 4.6D D GeV

c c c Dp

s

s s sD D D DK

Source: J. M. Izen, W. Dundoodie, X. C. Lou, MKIII

( )e e e e X


Estimate of ISR Signal Events

Decays

Produced events in 400 fb-1 of data (1000)

B.R.Det. Eff.

(%)

Events reconstructed

Relative

stat. error (%)

Super

B-factory ?

(%)

Ds branching fraction

~670 0.024 163

8 0.8

Ds leptonic decays

~670 0.039

260

4.5

(fDs)

0.5 ?

(fDs)

D+

leptonic decay

~2,800 0.001 40

16 1-2

~2,800 0.22 6,230

~1.3 ~0.1-0.2

c branching fraction

~450 0.025 112 ~9 ~1

J/(2S)

leptonic width

15,200

5,200

0.3

0.067

45600

3,500

0.5

1.7

0.05

0.2

| KD

Source: J. M. Izen, X. C. Lou


Charm Cross-sections near Thresholds

all Dtotal 6 nb

all Dstotal 1 nb

all ctotal 0.4 nb MKIII


Summary

• Much improved charm measurements with CLEO methods and 400 fb-1 of data around Upsilon(4S) B.R. measurements will be systematics limited

• New ISR technique brings potentials for B-factory experiments

charm physics before CLEO-c turns out physics results

continuous e+e- data below Upsilon(4S) over all

• The ISR approach at a Super B-factory may enable exploration

of physics between 10 > s > 0 GeV at ~1033 cm-2•s-1

s

Documents

X. C. Lou, Snowmass 20011 Charm Physics Potentials at B-factories XinChou Lou, University of Texas at Dallas Introduction Physics Topics: branching fractions,