Recent Results from Ψ(2S) and χ cJ Decays

1CPS2006,Sept. 15 - 17, 2006, Beijing Ping Rong-Gang

Recent Results from Ψ(2S) and χcJ Decays

平荣刚

IHEP, BeijingIHEP, Beijing

for the BES Collaboration

中国物理学会 2006 年秋季会议

CPS2006,Sept. 15 - 17, 2006, Beijing Ping Rong-Gang

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MKI MKII MKIII CBAL BESI BESII CLEOc

Data samples

3M

14M

6.42 pb-1 continuum data at Ecm=3.65 GeV for bkg study.

4M

2001.Nov.01to 2002.Mar.02


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DataMC+cont.+Bg.Cont.+Bg.Bg.


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M. Appelquist and H. D. Politzer, PRL34, 43 (1975)

12%B

B

B

BQ

eeJ/ ψ

eeψ'

XJ/ ψ

Xψ'h

This is the famous (or notorious)

“12% rule”.


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Violation revealed by Mark-II , confirmed by BESI at higher sensitivity.

Extensively studied by BESIIVP mode: , K*+K-+c.c., K*0K0+c.c., 0,…

PP mode: KSKL, K+K-, +-

VT mode: K*K*2, f2’, a2, f2

Multi-body: 3(+-), …

“12% rule” and “ puzzle”

K*K

ρπ

MARK-II

BESII : PLB614, 37 (2005); PRD73, 052007 (2006)CLEOc: PRL94, 012005 (2005)J/, ’ VP

mode

BESII:

B(’)(×10-5)

CLEOc:

B(’)(×10-5)

PDG04/BESII/…

B(J/)(×10-4)

B(’)/B(J/)

(%)

5.1±0.7±1.1 2.4+0.8-0.7±0.2 234±26 0.13±0.03

(2150) 19.4±2.5+11.5-3.4 N/A N/A N/A

+-0 18.1±1.8±1.9 18.8+1.6-1.5±2.8 200±9 0.92±0.11

K*+K-+c.c. 13.3±2.7±1.7 9.2+2.7-2.2±0.9 50±4 0.34±0.20

K*0K0+c.c. 2.9±1.7±0.4 1.3+1.0-0.7±0.3 42±4 2.6±0.6

1.87+0.68-0.62±0.28 2.5+1.2

-1.0±0.2 5.38±0.66 3.7±1.2 1.78+0.67

-0.62±0.17 3.0+1.1-0.9±0.2 1.93±0.23 10.9±3.4

’ 1.87+1.64-1.11±0.33 N/A 1.05±0.18 18±16

<0.40 N/A <0.064 N/A

3.3±1.1±0.5 2.0+1.5-1.1±0.4 8.98±0.92 3.0±1.2

’ 3.1±1.4±0.7 N/A 5.46±0.64 5.7±3.0 <3.1 N/A 23.5±2.7 <0.53’ 3.2+2.4

-2.0±0.7 N/A 2.26±0.43 14±11


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J/, ’ PP: 12% rule BES, PRL 92, 052001 (2004)

CLEO, hep-ex/0603020

KK mode enhanced relative to the 12% rule.Pure EM mode not enhanced, may be suppressed.J/ and ’ are related by ee of charmonia and form factors.

’ (10-5) J/ (10-4) Qh (%)

+– 0.8±0.8±0.2 (CLEO)

(<2.1 @ 90% C.L.)

1.47 ± 0.23

(PDG04)

5.4 ± 5.6

(<15@ 90% C.L.)

K+K– 6.3±0.6±0.3 (CLEO) 2.37 ± 0.31

(PDG04)

26.6 ± 4.6

KSKL 5.8±0.8±0.4 (CLEO)

5.24±0.47±0.48 (BE

S)

5.44 ± 0.54 (average)

1.82 ± 0.13

(BES04)

31.9 ± 5.4

28.8 ± 4.2

29.9 ± 3.7


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MCYXψ'

obsYXψ'

Xψ' εBNn

B

† This value from DM2 only Suppressed!!12 % 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(2004)072001


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’ 3-body

921±40914±42

256±18 44.8±8.7

PRD71,072006(2005); PRD74, 12004 (2006)


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Suppressed!!

’ 3-body BESII: PRD71, 072006 (2005)

BESII: PRD74, 12004 (2006)


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Multi-body ’ decays BESII, PRD73, 052004 (2006)


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Multi-body ’ decays

BESII, PRD73, 052004 (2006)

Some modes are suppressed, some are enhanced, while some others obey the 12% rule!


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Facts:

’ VP : suppressed’ PP : enhanced/supressed’ VT : suppressedMulti-body : obey/supRadiative : enhanced/supressed

Seems no obvious rule to categorize the suppressed, the enhanced, and the normal decay modes of J/ and ’.

Summary: “12%” rule


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BESII cJ→2(K+K)

Improved precision over PDG (BESI) results on cJKKKK and .

First measurement of cJKK.

c2

c0 c1

Pair production of vectors


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Pair production of vectors

BES: PLB630, 7 (2005)

First observation:

B(c0) =

(2.290.580.41)10-3

B(c2) =

(1.770.470.36)10-3

28c2

38c0


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BES: PRD73, 052006 (2006)

c0

cJ

Evidences for c0 and c0,2.

Agree with COM and QCM predictions.


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Summary of the test of color octet mechanism

● For χcJ →PP, the theoretical results are in general good agreement with experimental values .

●For χc0 →B Bbar, there is no reliable theoretical interpretation. The experimental values of Br(χcJ →Λ Λbar) decays are quite larger than theo. values.

● More experimental information are desirable for determining the color octec wavefunction of χcJ states.


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PWA on c0! +-K+K-.

Motivation :▲Compared with vector and pseudoscalar mesons, little information on scalar and tensor mesons are known.▲ The decays of cJ provide a direct window on studing of 0++ and 2++ mesons.

Different way for scalar study:1. Start from JPC=0++, 1++, 2++

2. Start from gluon+gluon3. Pair production of scalars, very different

from J/ decays


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1. Qi = 0 ; 2. p()+p( ) > 650 MeV [BG:’ J/ ]; 3. Prob( K K )> Prob(

)& Prob( K K )> Prob(

K K K K );4. M( ) [497±50] MeV/c2

& second vertex <5mm

[BG: KS ];

Even

t level

c0 K K

1.Avoid introducing a huge number of partial waves; 2. constrained by present statistics; our study is devoted to c0 K K

1371 events

c0

c1(3511.3±1.3MeV)

c0(3414.7±0.6MeV)

c2(3556.4±0.9MeV)

5C-

fit

BES: PRD72, 092002 (2005)


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( )( K K )

f0(1710) f0(2200) f0(980)

f0(1370)

(770)

BES: PRD72, 092002 (2005)

Q. Zhao, PRD72, 074001 (2005), try to understand these data and the scalars …


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(K )(K )

K*0/2(1430)

K*0(1950)

K*(892)0

With Kappa-kappa

Without Kappa-kappa

S=39.

BES: PRD72, 092002 (2005)


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1P1, 3P1 axial-vector-meson mixing:

1P1 : KA=cosθK1(1400) ＋ sinθK1(1270)

3P1 : KB=cosθK1(1270) ＋ sinθK1(1400)

1371 events

M(K ) [896±60] MeV

M( ) [700,850] MeV

K1(1270)

K1(1270)

K1(1400)

K1(1270)

BES, c0→+K+K

The mixing angle between K1A and K1B >57 degrees, while in ’

decays to K1K, the angle is <29 degrees (PRL83p1918). Why?

(K )K BES: PRD72, 092002 (2005)


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Summary PWA of c0 K K

From the c0 K K decay fit results, it is found thatscalar resonances have larger decay fractions compared to thoseof tensors, and such decays provide a relatively clean laboratoryto study the properties of scalars, such as f0(980),f0(1370),f0(1710),f0(2200) and so on.


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Event selection:

0

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2 24 4

0

1 15

2 3 1 0 05

3 0 15

0 5s

C

C C

recoil

S K

xy

. ( K ) .

( K ) ( )

. | m . | . GeV .

. K :| m m | . GeV ,

and L . cm

c2

c1

χc1→PPP allowed by spin-parity selection rule 　


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Nsig=418± 60

Nsig=58± 14 (4.5)Nsig=222±28 (8.8)

sidebanda sideband


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BES: cJ→KK and c0→PPP is suppressed by spin-parity selection;

χc1→PT allowed by spin-parity selection rule 　


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c c1 c2

PRD74, 12004 (2006)


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Summary

Thanks a lot !


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1P1, 3P1 axial-vector-meson mixing:

Nonstranger member: strange memeber

1P1 : b1(1235): G=+1 KA=cosθK1(1400) ＋ sinθK1(1270)

3P1 : a1(1260): G=-1 KB=cosθK1(1270) ＋ sinθK1(1400)

　　　　　　　　　　　　　　 θ ≈45°

Recent Results from Ψ(2S) and χ cJ Decays

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