1 Experimental review on “ puzzle” Changzheng YUAN Institute of High Energy Physics, Beijing...

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Experimental review on “ puzzle”

Changzheng YUANInstitute of High Energy Physics, Beijing

温都水城2011 年 3月 18 日

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Contents

• experiments

• “12% rule” & “ puzzle”– A bit history

& VP

– VT

– Other modes

• Questions for discussion

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BES and CLEOc dataData BESII CLEOc BESIII (2012)

J/ 58 M -- 225 M (x5)

’ 14 M 26 M 106 M (x5)

’’33 pb-1 818 pb-1 2200 pb-1 (2900 pb-

1)

Continuum

6.4 pb-1

(s=3.65 GeV)21 pb-1

(s=3.67 GeV)42 pb-1

(s=3.65 GeV)Performance BESII CLEOc BESIII

p/p1.7%/1+p2 0.6%@p=1Ge

V0.5%@p=1Ge

V

E/E22% /E 2.2%@E=1Ge

V2.5%@E=1Ge

V

PartID dE/dx+TOF dE/dx+RICH dE/dx+TOFCoverage 80% 93% 93%

Almost no publications from BESIII yet …

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The “12% rule”

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”.

It’s 13% now, was 12%, 14%, or 15%.

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Violation found by Mark-II , confirmed

by BESI at higher sensitivity. Extensively studied by BESII/CLEOc

VP mode: , K*+K-+c.c., K*0K0+c.c., 0,…PP mode: KSKL, K+K-, +- [Xiaohu’s talk]BB mode: pp, , …VT mode: K*K*2, f2’, a2, f2

3-body: pp0, pp, +-0, …Multi-body: KSKShh, +-0 K+K- , 3(+-), …

“12% rule” and “ puzzle”

K*K

MARK-II

6

BES

I st

ud

ies

of

th

e

“12

% r

ule

”

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BESII: 强烈压低与反常增强

KSKL

1.多数过程满足“ 12% 规则”2.首次观测到 (2S)，发现强烈压低；比“ 12% 规则”压低近两个量级

3.首次观测到 (2S)VT ，发现中等压低；比“ 12% 规则”压低几倍

4.首次观测到 (2S)KSKL，相对于理论预期反常增强 !

理论预期

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In Potential model, if J/, ’, and ’’ are pure 1S, 2S,

and 1D states, one expects [PDG2010]

Extension of the “12% rule” to ’’

0.3)%(13.0B

B

B

BQ

eeJ/ ψ

eeψ'

XJ/ ψ

Xψ'h

4-

eeJ/ ψ

ee'ψ'

XJ/ ψ

X'ψ'h 100.12)(1.63

B

B

B

BQ'

but ’ and ’’ are known not pure 2S and 1D states

PRD17, 3090 (1978); 21, 203 (1980); 41, 155 (1990); …

Let’s look at data …

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BESII CLEOc

229 0s 196 0s

BES and CLEOc in good agreement!

BESII: PLB619, 247 (2005)CLEOc: PRL94, 012005 (2005)’ + - 0

56.15.1

0

50

10)8.28.18()'(:

10)9.18.11.18()'(:

BCLEOc

BBESII

10

Dalitz plots after applying 0 mass cut!

Very different from J/ 3!

Similar Dalitz plots, different data handling techniques:

PWA vs. counting!

J/

’ + - 0

CLEOcBESII

58.07.0

5

10)2.04.2()'(:

10)1.17.01.5()'(:

BCLEOc

BBESII

’ is observed, it is not completely missing, BR is at 10-5 level!

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J/ + - 0

)%12.007.2()/( 0

JB

Make mass cut, and count events

PWA analysis assuming interferes with excited states

L. P. Chen andW. Dunwoodie, Hadron’91, MRK3 data

?)%101(17.1)/(

)/(0

JB

JB

%0.282.42ρπ)B(J/ ψ

Very different!

PDG: 1.690.15%

数据引用不对！

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BESII

3.773GeV

BES and CLEOc are in good agreement!X-section at ’’ peak is smaller than at continuum!

BESII: PRD72, 072007 (2005)CLEO: PRD73, 012002 (2006)’’ + - 0

pbCLEOc

pbBESII

GeVeeB

)2.14.04.7(:

)0.25.34.8(:

: 773.3@)( 0

3.650GeV 3.773GeV3.670GeV

CLEOc

pb

pb

continuum

)1.21.13(

)7.33.73.19(

:@

9.17.1

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BESII: PRD72, 072007 (2005)CLEO: PRD73, 012002 (2006)

BESII

3.773

BES and CLEOc are in good agreement!X-section at ’’ peak is smaller than at continuum! non-zero ’’ amplitude.

’’ + - 0

pbCLEOc

pbBESII

GeVeeB

)5.03.04.4(:

0.6:

:773.3@)(

3.65

CLEOc

pb

pb

continuum

)9.00.8(

25

:@

7.14.1

3.773 3.67

Subtle difference in handling efficiency and ISR correction.

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’’ Wang, Yuan and Mo:PLB574,41(2003)

Tot

al c

ross

sec

tion

2

*

2

**''''

:

:

ee

Boff

eegggBon

a

peakresonanceoff

aaa

peakresoanceon

2

*'''')''( aaB ggg

B depends on efficiency and ISR correction, efficiency and ISR correction depends on B(s) ! Iteration is necessary!

1L

nobsB

Three unknowns with two equations --- One can plot the BR versus phase .

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’’ BES data restrict BR and phase in a wide range (@90% C.L.):

20,150

104.2,106 36

BR

CLEOc data further restrict BR and phase in a ring*. At =-90:

54.30.2

3

104.2

103.01.2

BR

or

BR

*Toy MC is used to get BR from CLEOc data (not CLEO official results)!

BESII: PRD72, 072007 (2005)CLEOc: PRD73, 012002 (2006)

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In S-D mixing model, using mixing angle θ=12°, using Rosner’s assumption (12% rule for 1S and 2S), one predicts Q’

ρπ =(2.7-5.3)% !

J/ , ’ , ’’

)%..(ρπ)B(J/ψ

ρπ)B(ψ050130

'

)%.(ρπ)B(J/ψ

ρπ)B(ψ

or

)%..(ρπ)B(J/ψ

ρπ)B(ψ

.

.150090100

''

6109''

13.0%Qe

0.016%Q'e

keV

or

keV

keV

keVJ

6.0)''(

50)''(

014.0)'(

1.2)/(

•Partial width of ψ’’ρπ is larger than that of ψ’ρπ!•hard to understand if ψ’’ is pure 1D state, also hard if ψ’’ is 2S and 1D mixture.

-90 or imperfect model?

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’ VP K*(892)K+c.c.

K*0

Br±=(2.9±1.7 ±0.4)10–5

Br0=(13.3±2.7 ±1.7)10–5 K*

Good agreement!Large Isospin violation!Both modes suppressed!

BESII : PLB614, 37 (2005)

CLEOc: PRL94, 012005 (2005)

Br0=(9.2±2.7 ±0.9)10–5

Br±=(1.3±1.0 ±0.3)10–5

BESII

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

mode

BESII:

B(’)(×10-5)

CLEOc:

B(’)(×10-5)

PDG2010

or my est.…

B(J/)(×10-4)

B(’)/B(J/)

(%)

5.1±0.7±1.1 2.4+0.8-0.7±0.2 242±28 0.13±0.05

(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±2.8 207±12 0.92±0.11

K*0K0+c.c. 13.3±2.7±1.7 9.2+2.7-2.2±0.9 43.9±3.1 2.6±0.6

K*+K-+c.c. 2.9±1.7±0.4 1.3+1.0-0.7±0.3 51.2±3.0 0.34±0.20

1.87+0.68-0.62±0.28 2.5+1.2

-1.0±0.2 4.5±0.5 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 7.5±0.8 3.0±1.2

’ 3.1±1.4±0.7 N/A 4.0±0.7 7.8±4.1

<3.1 <1.1 17.4±2.0 <0.53

’ 3.2+2.4-2.0±0.7 N/A 1.82±0.21 14±11

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Search for ’’VPCLEO: PRD73, 012002 (2006)

Same operation as for ’’ should done for all the modes to extract the BRs of ’’ decays.

BR

(’’

fina

l sta

te)

=-90 degrees as in J/ and ’ decays? Any way to choose one solution?

Some x-sections agree, some very different.

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)1270(2f

f2 (1270)

B.G.(M.C.)

B.G.( )

’ V T

B.G.

a2 (1320) )1320(2a

BESII ： PRD69, 072001 (2004)

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)1430()892( 20

B.G.

K*2 (1430)

K*(892)

’ V T

)1525(2f

B.G.

f2' (1525)

f0(980)

BESII ： PRD69, 072001 (2004)

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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)

(PDG2010)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 6.0±0.6 3.1±1.3

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

BESII ： PRD69, 072001 (2004)

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Multi-body ’ decays BESII: PRD71, 072006 (2005)

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

CLEOc:PRD72, 051108(2005)

BESII, PRD73, 052004 (2006)

CLEOc: PRL95, 062001 (2005)

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Multi-body ” decays

25 modes, no significant signal observed over continuum expectation.

CLEOc: PRL96, 032003 (2006)

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Multi-body ” decays [references by PDG2010]

Many publications, but no significant signal in even one single mode! (mystery!!)

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BESIIIPRL105, 261801 (2010)

NEW information!

J/ & ’0, & ’

4.6 4.3

)

’’

’0

’

Mode B(’) [x10-6] B(J/) [x10-4] Q (%)0 1.580.42 0.350.03 4.5 1.3 1.380.49 11.040.34 0.13 0.04’ 1269 52.81.5 2.4 0.2

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The “12%” rule and the “0.02%” rule’ VP/P suppressed’ PP enhanced’ VT suppressed’ BB obey/enh.Multi-body obey/sup

The ’’ decays into light hadrons may (not) be large --- more data and more sophisticated analysis are needed to extract the branching fractions from the observed cross sections. Why D-wave decay width so large?

Model to explain J/, ’ and ’’ decays naturally and simultaneously? •S-D mixing in ’ and ’’ [J. L. Rosner, PRD64, 094002 (2001)] [Wang Ping]•DD-bar reannihilation in ’’ (J. L. Rosner, hep-ph/0405196)•Four-quark component in ’’ [M. Voloshin, PRD71, 114003 (2005)]•Survival cc-bar in ’ (P. Artoisenet et al., PLB628, 211 (2005))•Other model(s)?

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

The models developed for interpreting specific mode may hard to find solution for other (all) modes.

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Summary

Lots of progress from BESII and CLEOc in vector charmonia decays.Hadronic decays of J/, ’, and ’’ are studied extensively and simultaneously to understand the decay dynamics.“ puzzle” remains a puzzle, ’’ charmless decays is observed in inclusive mode, but the total rate for the charmless decay is very uncertain & suspecious.More studies are needed (and expected) at BESIII!

Thanks a lot!

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你再问我为什么，我就揍你！

为什么？

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For discussion• Do you have any suspicions on experimental data? [Still assumptions in extracting experimental results,

be careful in citing BRs]• What is the desired precision?• Are there better ways to categorize data rather than i

nto (quasi-two-body) VP, VT, PP, AP, …?• Are there crucial modes still missing?• How reliable is the 12% rule?• J/ enhanced? ’ suppressed? Or both?• Should there be difference between strong decays an

d EM decays (in terms of the BR ratio)?

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For discussion ’’ decays add more information or just trouble?• Can bottomonia decays help? • How can experimentalists & theorists make joint effor

t in understanding the problem?

32CLEO preliminary results never published!

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