recent results on (2s) and cj decays from bes
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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 !
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