(2S) radiative and hadron(2S) radiative and hadronic transitions at BESic transitions at BES

International Workshop on Heavy Quarkonium

October 12-15, 2004 , IHEP Beijing

Zhiyong Wang

IHEP, Beijing ,ChinaIHEP, Beijing ,China

for the BES Collaboration

BESII Detector

VC: xy = 100 m TOF: T = 180 ps counter: r= 3 cm MDC: xy = 220 m BSC: E/E= 22 % z = 5.5 cm dE/dx= 8.5 % = 7.9 mr B field: 0.4 T p/p=1.7%(1+p2) z = 3.1 cm

World J/ and (2S) Samples (×106)

J/ (2S)58 M 14 M

0

2

4

6

8

10

12

14

MKI MKII MKIII CBAL BESI BESII CLEO

0

10

20

30

40

50

60

MarkIII DM2 BESI BESII

outline

(2S)0J/,0

(2S)J/,

(2S)c1 , c1 J/

(2S)c2 , c2 J/

J/(BES-II data)

X+J/

(BES-I data)

(2S)J/

(2S)J/

(2S)c1 , c1 J/

(2S)c2 , c2 J/

J/e+e ， +

J/+

Charmonium SystemCharmonium System

Measure: ' oJ/, J/ ' cJ J/ (J=1,2)• Old measurements disagree.• B(’ oJ/) very crude:

(23 evts at CBAL, 7 evts at MRK2).• Theoretical predictions for charmonium hadronic

transition amplitudes can be tested by high statistics measurements.

' J/

0162.0)/)2((

)/)2(( 0

JS

JSR

0025.0)/)2((

)( ''

JS

R

0013.0)/)2((

)( ''''

JS

R

Channel

PDG2002 Branching

Ratio

Experiment Data

Sample(M)

Events

0 J/ (9.72.1)10-4

(15.66)10-4 MARK-II(1980) 1.0 7

(921)10-4 CBCL(1980) 1.8 13

J/(3.130.21)%

(4.30.8)% MARK-I(1980) 1.0 44

(2.550.29)% CBAL(1980) 0.78 386

(4.20.6)% CNTR(1978) 0.63 164

(4.51.2)% DASP(1979) 17

C1(8.40.7)%

(9.00.50.7)% CBCL(1986) 1.8

(7.11.9)% CNTR(1977) 0.63

C2(6.80.6)%

(8.00.50.7)% CBAL(1986) 1.8

(7.02.0)% CNTR(1977) 0.63

Previous experiment results((2S)…)

' J/

J/

0J/

cJ J/

' J/

BKG from 00J/

J/e+e or +, 5C (J/ mass) kinematic fit is applied!

Take +

final state as

an example

MC

(2S) → J/

' J/ (2S) → 0J/

e+e +

(2S) → cJ → J/

(2S) → cJ → J/

+

e+e

+ e+e

' J/

PDG04 2.67 ± 0.15 1.30 ± 0.08

' J/

oJ/

J/

c1

c2

BES measures the BRswith high precision!

BES

Phys.Rev.D70:012006,2004

BES most

accurate

’ J/ Discussions

R<0.0098

R<0.0065

00162.016

27

)/)2((

)/)2(( 2

20

rp

p

JS

JSR

2

22

222

2

ˆ1

ˆ

32

1

16

27 0

mm

f

AB

mm

f

AB

rp

pR

0013.0))2((

)(

))2((

)(

)/)2((

)(

0025.0))2((

)(

))2((

)(

)/)2((

)(

232

232

Sf

f

Sp

p

m

m

JSR

Sf

f

Sp

p

m

m

JSR

b

c

b

c

BES result: R=0.048±0.007

BES (+PDG for ):

PCAC [G. A. Miller, Phys. Rep. 194,1(1990)]:

Casalbuoni et al: give an improved expression

[PLB 309,163(1993)], but A and B are unknown

QCD Multipole Expansion & BTG potential model [Y. P. Kuang, PRD24, 2874(1981), ibid. 37, 1210(1988)

B/A=-1.420.12

B/A=-3.11 0.15

' X J/ B((2S) hadrons)/B(J/ hadrons) =

B((2S) ggg + gg)/B(J/ ggg + gg)

= 0.23 ± 0.07

Disagrees with “12 % Rule”

Important to measure ’ X J/ and

components.

M. Suzuki, PRD63,

054021, (2001).

Y. F. Gu and X. H. Li,

PRD63, 114019 (2001).

Method – identify J/+

Select muons.

1 C fit to mJ/

determine mX

pX

p μ-p μ+ pJ/

' X J/

J/ peak

Background

e+ e- μ+ μ - and

e+ e- ’ μ+ μ -

Fit distribution:

• background (mμμ < 3.4)

1307 events

• signal 44498 events

Inclusive measurement – use events that satisfy 1 C fit.

' X J/

To separate ’ 00 J/ and + J/, plot mX for

no extra charged tracks and for extra charged tracks.

Fit two simultaneously with component shapes.

00

η

c1c2

backgrd

no extra extra

+

η

2 < 7

Exclusive measurements

' X J/

Results

Phys.Rev.D70:012003,2004

measured

BESI – 4 million (2S) events.

Determine ratio of branching ratios to

B(’ + - J/ ) to cancel systematic errors.

Constrain C2/c1 since shapes similar.

Summary

• The precision of B((2S)0J/, 00J/ J/,c1,2) are improved, especially for B((2S)0J/)

• Some theoretical models are tested by our new measurement results

Thank you ! 谢谢 !