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1
Experimental review on “ puzzle”
Changzheng YUANInstitute of High Energy Physics, Beijing
温都水城2011 年 3月 18 日
2
Contents
• experiments
• “12% rule” & “ puzzle”– A bit history
& VP
– VT
– Other modes
• Questions for discussion
3
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 …
4
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%.
5
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
”
7
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
8
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 …
9
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!
11
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!
12
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
13
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.
14
’’ 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 .
15
’’ 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)
16
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?
17
’ 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
19
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.
20
)1270(2f
f2 (1270)
B.G.(M.C.)
B.G.( )
’ V T
B.G.
a2 (1320) )1320(2a
BESII : PRD69, 072001 (2004)
21
)1430()892( 20
B.G.
K*2 (1430)
K*(892)
’ V T
)1525(2f
B.G.
f2' (1525)
f0(980)
BESII : PRD69, 072001 (2004)
22
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)
23
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)
24
Multi-body ” decays
25 modes, no significant signal observed over continuum expectation.
CLEOc: PRL96, 032003 (2006)
25
Multi-body ” decays [references by PDG2010]
Many publications, but no significant signal in even one single mode! (mystery!!)
26
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
27
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.
28
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!
29
你再问我为什么,我就揍你!
为什么?
30
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)?
31
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!
33