Recent Results on (2S) and cJ Decays

from BESZhiyong Wang

IHEP, Beijing ,ChinaIHEP, Beijing ,China

for the BES Collaboration

VietNam 2004 5th Rencontres du Vietnam

Particle Physics and Astrophysics Hanoi

August 5 to August 11, 2004

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

0

2

4

6

8

10

12

14

MKI MKII MKIII CBAL BESI BESII CLEOc

BESII obtained 14 M ’ events

Nov.01-Mar.02

’ VP

’ VT

’ PP (K0S K0

L)

J/-contained

cJ , pp, f0f0

Other ’ and cJ

decays

3M

14M

pQCD rule (12% rule)

[the relation between J/ and ’ ]

Violation was revealed by MARK-II ,

confirmed by BES at higher sensitivity.

Provide information for understanding

the charmonium decay dynamics.

“pQCD rule” and “ puzzle”

12%B

B

BB

QeeJ/ψ

eeψ'

XJ/ψ

Xψ'h

K*K

ρπ

MARK-II

The Relative Phase

J/ψ Decays: 1. AP: 90 ° M. Suzuki, PRD63, 054021 (2001) 2. VP: (106 ±10) ° J. Jousset et al., PRD41, 1389 (1990) D. Coffman et al., PRD38, 2695 (1988) N. N. Achasov, talk at Hadron2001 3. PP: (90 ±10) ° M. Suzuki, PRD60, 051501 (1999) 4. VV: (138 ±37) ° L. Köpke and N. Wermes, Phys. Rep. 74, 67 (1989) 5. NN: (89 ±15) ° R. Baldini et al., PLB444, 111 (1998)

ψ’VP 1. φ=180 ° (90 ° ruled out!) M. Suzuki, PRD63, 054021 (2001)

2. φ= 90 ° or φ=180 °﹣ (with continuum amplitude) P. Wang, C. Z. Yuan and X. H. Mo, PRD69, 057502 (2004)

φ

Measure the relative phase in e+e – experiment

phase

Take the continuum contribution and its interference effect into consideration , we could determine not only the magnitude but also t

he sign of the phase.

φ

interference interference

’ VP

K*+K-+c.c., K*0K0+c.c., 0

’ VT

f2 , a2 , K* K*2 , f2

'

’ PP

K0S K0

L

(also J/ decays)

In this talk, I will cover

for pQCD rule and phase study!

’ VP K*(892)K+c.c.

K* K*2(1430)

B.G.

K*0

9.6±4.2evts, 3.5σ

65.6±9.0evts, 11σ

Br± =(2.9±1.3 ±0.4)10–5

Br0=(15.0±2.1 ±1.9)10–5

K*

K*0

K*2(1430)

B.G.

BES preliminary!

First observation!Large Isospin violation!

’ VP 0

B.G.

0

B.G.0

@3.686GeV& L=(19.72 ±0.86) pb 1

@3.650GeV& L=(6.42 ±0.24) pb 1

Expects 22 continuum background events in ’ sample!

31.2 ±7.2 evts.

7.4 ±2.8 evts.

BES preliminary!

Information on continuum data is very important for ’ analyses!

VP

ModeB(’X )(10 – 5)

B (J/X )(10 – 4)

(PDG2002)Qh ( % )

0 1.840.640.27 4.20.6 4.41.8

K*0 K0+c.c. 15.0±2.1±1.9 42±4 3.6±0.8

K*+ K–+c.c. 2.9±1.3±0.4 50±4 0.58±0.27

BES-II results (Preliminary)

12% rule

’ V P

Suppressed !!

7.22.5.).'(

.).'(*

00*

ccKKB

ccKKB

Large isospin violation indicates EM decay important!

’ V T

f2 +–0 +–

a2

K* K*2

K K f2

'

KK KK

+ – + – 0

K+ K– + –

’ + – + – 0

K+ K– K + K –

)1270(2f

f2

(1270)

B.G.(M.C.)

B.G.( )

’ V T

B.G.

a2 (1320)

)1320(2a

02

0 )1430()892(

B.G.K*

2 (1430)

K*(892)

)1525(2f

B.G.

f2' (1525)

f0(980)

MCYXψ'

obsYXψ'

Xψ' εBNn

B

† This value from DM2 only Suppressed!!12 % rule ( pQCD rule )

’ V T

VT mode

B’ X (10 – 4)

(BES-II)

B J/X (10 – 3)

(PDG2002)Qh(%)

f2 2.05± 0.41 ± 0.38 4.3±0.6 4.8±1.5

a2 2.55± 0.73± 0.47 10.9±2.2 2.3±1.1

K* K*2 1.86± 0.32 ± 0.43 6.7±2.6 2.8±1.3

f2' 0.44 ± 0.12 ± 0.11 1.23±0.21† 3.6±1.5

PRD69, 072001 (2004)

Ks mass sidebands

Bkg MC

signal

14M ψ(2S)

’ KS KL

PRL 92, 052001 (2004)

Ks mass sidebands

MC BkgK*0KS+c.c.

signal58M J/ψ

J/ KS KL

PRD 69, 012003 (2004)

B (’

KS K

L )

=5.24

10 – 5

Yuan, Wang, Mo: PLB567 (2003)73

K+K– & +

inputs ;Input 1:DASP;Input 2:BESI ;Input 3: K+K–

from BESI & + by form factor.

’ KS KL

–(8229)° (12127) °

First measurement of the phase in ’ decays!

12%BB

QXJ/ψ

Xψ'h

B ’ Ks KL = (5.24± 0.47 ± 0.48 ) 10 – 5

B J/ Ks KL = (1.82 ± 0.04 ± 0.13 ) 10 – 4

4.3)%(28.8B

B

LKKJ/ψ

LKKψ'

S

S

4B(’) enhanced!

J/ , ’ KS KL

’ J/-Contained

Motivation: Improve Exp. Precision and Test Theory Calculation

Inclusive Method [BES-I]

XJ/ , J/ + –

----------------------------------------------------------

Anything J/

00 J/J/

c1 , c1 J/

c2 , c2 J/

Exclusive Method

[BES-II]

J/ , J/ l+ l –

-----------------------------------------------------

0 J/J/

c1 , c1 J/

c2 , c2 J/

Phys.Rev.D70:012003,2004

Phys.Rev.D70:012006,2004

BES measures the BRsin high precision!

c2

c1

J/

oJ/

First measurementB(´00 J/)=(18.2± 1.2)%

XJ/ BES

’ J/ Discussions

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

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

mmf

AB

mmf

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

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

BES (+PDG for ):

Casalbuoni et al:

improved expression

[PLB 309,163(1993)]

Λ signal in πp mass

Clear Λ Λ-barSignal

Data

Monte Carlo

cJ

Fit the mass spectrum

χc0

χc1 χc2

MC efficiencies

ΛΛ-bar Mass (GeV)

cJ

c0

c2

c1

ppχ cJ Final states: γpp-bar

PRD69, 092001(2004)

c0

c0f0(980) f0(980)

c2

KsKs

No c2f0(980) f0(980)

Evidence for c0 f0f0

preliminary!

f0(980) recoil mass (m=0.93-1.03 GeV)

f0(980) side bands events recoil mass

Two entries/event

c0f0(980) f0(980)

•Strong evidence for c0f0(980) f0(980)

4.6•B(c0f0f0, f0+-) =(7.5±1.9±1.7) ×10-4

preliminary!

Final states with KSKS in ’ decays

From 14M ’ (preliminary!)

Many channels are first observation, useful for comparing with Isospin conjugate final states!

’ VP channels K* K and are first observed. Large isospin violation effect in K* K mode. BES confirms the VP suppression in ’ decays.’ VT channels f2 , a2 , K* K*

2 and f2'

are first observed and branching ratios are measured. All are suppressed in ’ decays.First observation of K0

S K0L in ’ decay.

Improved measurement of J/ψ K0S K0

L . ’ is enhanced relative to the pQCD 12% rule.

’ J/-contained final states are to improve experimental

precision and test theoretical predications. cJ , f0f0 and p p are measured and cJ , f0f0 are first observed. Other ’ and cJ decays are also measured and some of them are first observed

Summary

Thanks a lot !

谢谢 !