Recent results of Recent results of ψ' decays at BEψ' decays at BESS

WANG Zheng

CCAST, Beijing,10049 China

For BES Collaboration.

The International Conference on QCD and Hadronic Physics

Jun. 16-20, 2005, Peking University, Beijing, China

Outline

•BES results of Ψ´ hadronic final state decays.

•Ψ´ hadronic and EM transition measurement.

•Summary.

VP mode: , K*+K-+c.c., K*0K0+c.c., 0,…

PP mode: KSKL

3 or-multi-body: pp0, pp, +-0,3(+-), …

(2S)(, η or 2 photons) +J/

BES Detector and the data

0

2

4

6

8

10

12

14

MKI MKII MKIII CBAL BESI BESII CLEOcTracking: Main Drift Chamber

Photon ID: BSCHadron ID: MDC(dE/dx)+TOF

6.42pb-1 continuum data (Ecm=3.65GeV) to estimate the continuum bg.

14 Million

From “12% rule” to “ρπ puzzle”J/ and ’ hadronic decays proceed via 3 gluons or a virtual photon, neglect the difference of S at J/ and ’ , the ratio of ’ and J/ BRs is :

Qh= )ee/J(B)ee)S2((B

)/J())S2((

)ggg/J(B)ggg)S2((B

3s

3s

≈12%

MARK-II

K*K

ρπ

Violation was observed by MARK-II ,

Confirmed by BESI at higher sensitivity.

Theoretical explanationsMany theoretic attempts, using, for instance, intermediate vector glueballs, hadronic form factors, final states interactions, etc. try to solve the puzzle.

A recent study originally proposed by J.L. Rosner shows that the S- and D-wave mixing model probably gives a unified explanation for 12% rule violation decays. (PRD64, 094002 (2001))

This mode developed by BES members by adding interference between continuum and ψ" amplitudes, may possibly explain the 12% rule, and can give some prediction for " decays. (Wang, Yuan and

Mo:PLB574,41(2003))

<f |> = <f | 23S1> cos – <f | 13D1>sin, <f | > = <f | 23S1> sin + <f | 13D1>cos.

(=12º)

“12%” rule:|<f|J/>|2/|<f|23S1>|2 = ee(J/)/ee(23S1) <f | 23S1> (Rosner’s assumption)

MK3 UL (<6.3pb)Favors φ= 90°﹣

Ob

served C

ross S

ection

of

Ψ"

ρπ

Therefore measurements at J/, , and can be used to test the model !

BES results of ψ´ VP Decays

’ + - 0

Event Selection

Prob_4C

1. Two charged tracks with net charge zero;2. |cosθ|<0.80 for all tracks, TOF and dE/dx for part ID;3. photon ID: E>0.08GeV, far from charged tracks

4. Remove ψ’ π﹢π﹣J/ψ and Bhabha background;5. Kinematic fit (4C), Prob>0.01.

Bhabha

+ - 0

hep-ex/0408047 PLB in Press

PWA of Ψˊ→π+π -π0

hep-ex/0408047 PLB in Press

ΨˊData Continuum Data

Two photons invariant mass

Continuum contributions are subtracted incoherently in 3πevents.

(26019) 0s(104) 0s

Number of ψ(2S)+ - 0: 22923

PWA of Ψˊ→π+π -π0

Ψ(2S) peak

13% bkg

Ψ(2S) peak

13% bkg

3.65 GeV

42% bkg

J/Ψ→μμ decay veto

ρ(770) band

Very different from J/Ψ 3! Need PWA to extract ρπ signal!

J/Ψ

PWA Ψˊ→ π+π -π0

•ML fit for the Dalitz plot.

•Helicity amplitude:

•ρ and its excited states.

•ρ was described by Gounaris-Sakurai(GS) parameter.

Ψˊ π

πρ

π

PWA of Ψˊ→π+π -π0

in Ψˊ→3π process. (770)π, (2150)π are dominant.

3π: (770)π: (2150) π

= 1:0.28±0.03:1.07±0.09

PWA of Ψˊ→π+π -π0

hep-ex/0408047 PLB in Press

K* K*2(1430)

B.G.

K*0

9.6±4.2evts, 3.5σ

65.6±9.0evts, 11σ

Br± =(2.9±1.7 ±0.4)10–5

Br0=(13.3±2.7 ±1.7)10–5

K*

K*0

K*2(1430)

B.G.

First observation!Large Isospin violation!

PLB614, 37 (2005)

K*(892)K+c.c. KS K+-+c.c.

VP

ModeB(’X )(10 – 5)

B (J/X )(10 – 4)

(PDG2004)Qh ( % )

K*0 K0+c.c. 13.3±2.7±1.7 42±4 3.2±0.8

K*+ K–

+c.c. 2.9±1.7±0.4 50±4 0.58±0.35

12% rule

K*(892)K+c.c. KS K+-+c.c.

Suppressed !!

CONTINUUM CONTRIBUTION SUBTRACTED INCOHERENTLY!

9.26.4.).'(

.).'(*

00*

ccKKB

ccKKB

The isospin violation observed here also indicates EM decay , continuum contribution and their interference are important in Ψ´ physics.!

PLB614, 37 (2005)

Ψ´η, η’, η, η’

π0, η η’ η’

η η’ η’

PRD70 (2004) 112003

ψ ´ η, η’, η, η’

PRD70 (2004) 112003

No event observed in continuum data sample for such decay modes!Subtraction of zero event continuum background are also taken into

consideration in systematic error analysis! !

EM Process: 0,,ˊ at Ecm=3650,3686,3773 MeV

EM process, hep-ex/0410031

interference

For EM processes at continuum e+e- (VP) 0 , , ˊ

Pvp(S)=q3vp/3 ; q3

vp – momentum of V or P ; Fvp(s) – form factor .

For EM processes at Ψˊ (VP) 0, , ’ =R+cont (INT 0, P.Wang et al, PL B593 (2004) 89 )

BRs (M Ψ(2S) ) & Fvp obtained simultaneously.

EM Process: 0, , ˊ at Ecm=3650, 3686, 3773 MeV

Ecm=3650 MeV L = 6.42 pb-1 Ecm=3686 MeV N Ψ(2S) = 14M Ecm=3773 MeVL = 17.3 pb-1

ωπ0

ρη

ρηˊ

0 form factor

Curve A -- J.Gerard, PLB425(1998)365 F(0) ~ 1/s

Curve B –V.Chernyak, hep-ph/9906387 F(0) ~ 1/s2

0,,’ at Ecm=3.65, 3.686,3.773 GeV

PRD70 (2004) 112007

Born order cross section, from factor, and branching fraction measurement of the VP isospin violating decays.

Test of pQCD 12% Rule

PQCD 12% Rule test using BESII Ψˊ→VP results

12% Rule

ρπ signal is missing at ψ" because of destructive interference between the continuum amplitude and ψ(3770) amplitude(φ=-90o). That indicate BR(ψ(3770)ρπ ) at 10-4 level.

ψ"ρπ, testing the S-D mixing mode

25145

103.2)''(103.1 35

BBESII

data: 17.3 pb-1

is the relative phase between strong and EM decays.

BESIII or CLE

Oc

Model prediction

In S-D mixing model by Rosner, ψ(3770)ρπ process is predicted to be enhanced! Considering the continuum amplitude, the observed cross section and BR of ρπ decay at ψ(3770) are predicted in Wang, Yuan and Mo:PLB574,41(2003). So the measurement of ψ(3770)ρπ is a test of the S-D mixing mode for the explanation of the “ρπ puzzle” .

BE

S prelim

inary

BES results of ψ´ PP decay, multi-

body Decay

Study of ψ´p π0(η)

0: 25618

: 44.8 8.7

PRD71, 072006 (2005)

P

P

p

ψ´ Multi-body decays

hep-ex/0503040, BES preliminary

410)87.042.045.5())(3)2(( SBr

Ks mass sidebands

Bkg MC

signal

14M ψ(2S)

´ (J/ψ) KS KL

PRL 92, 052001 (2004)

58M J/ψ

PRD 69, 012003 (2004)

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

3.7)%(28.8B

B

LKKJ/ψ

LKKψ'

S

S

’ decay enhanced more than

4 σ

' , J/ KS KL

BES results of ψ´ hadronic and E

M transitions

´ strong and EM transition(motivation)

0162.0)/)2((

)/)2(( 0

JS

JSR

0025.0)/)2((

)( ''

JS

R

0013.0)/)2((

)( ''''

JS

R

Prediction of transition

amplitude ratio by PCAC (Partially Conserved Axial-Vector

Currents) theory.

Prediction of transition am

plitude ratio by QCD multipole expansion theory.

•Old measurements do not agree well.• B(’ oJ/) is measured with low precision: (23 evts at CBAL, 7 evts at MRK2).• Meanwhile, results of high statistics measurements can test theoretical predictions by PCAC(Partially Conserved Axial-Vector Currents),QCD multipole expansion, i.e. for charmonium hadronic transition amplitudes.•Inclusive Ψ´X+JΨ measurement is also useful to test “12% rule”.

Measure: ' oJ/, J/ , ππJ/ ' cJ J/ (J=1,2) J/ are reconstructed by two leptons.

´ strong and EM transition

Phys.Rev.D70:012006,2004Charmonium System under DDbar threshold. Charmonium System under DDbar threshold.

J/

0J/

cJ J/

' J/

BKG from 00J/

J/e+e or +, 5C (J/ mass) kinematic fit is applied!

Take +

final state as

an example

MC

Two photons Inv. Mass distribution for (2S) → J/

' J/

Two photons Inv. Mass distribution for (2S) → 0J/

e+e +

(2S) → cJ → J/

Inv. Mass distribution of J/

+

e+e + e+e

' J/

PDG04 2.67 ± 0.15 1.30 ± 0.08

' J/

oJ/

J/

c1

c2

BES measures the BRswith high precision!

BES

Phys.Rev.D70:012006,2004BES most

accurate

' J/ Discussion

• PCAC prediction R=0.0162 is smaller than our measurement by a factor of 3. [G. A. Miller, Phys. Rep. 194,1(1990)]:

BES (+PDG for ):

R= 0.048 ± 0.007R' < 0.0098R" < 0.0065

• Consistent with the prediction byQCD Multipole expansion & BTG potential model [Y. P. Kuang, PRD24, 2874(1981), ibid. 37, 1210(1988)]

R' = 0.0025R" = 0.0013

Phys.Rev.D70:012006,2004

' X J/

Method –

J/ signal is reconstructed by J/+

Select muons. 1 C fit to mJ/

Obtained the mass recoiling against the J/Ψ (mX) from energy and momentum conservation.

The exclusive BRs are determined from fits mass distribution of X.

At last, report the ratios of the studied BRs to that for B(’ π+π- J/ )

pX

p μ-p μ+ pJ/

PRD70,012003(2004)

BES 4M Ψ(2S) data

' X J/

J/ peak

Background

e+ e- μ+ μ- and

e+ e- ’ μ+ μ-

Fit distribution:

• background (mμμ < 3.4)

1307 events

• signal 44498 events

' X J/ fit result

To separate ’ 00 J/ and + J/, plot mX for no extra charged tracks and for extra charged tracks. Fit two simultaneously with component shapes.

00

η

c1c2

backgrd

no extra charged track extra charged track

+

η

2 < 7

Mx distribution obtained from the mass recoiling against J/Ψ

' X J/

Phys.Rev.D70:012003,2004

measured

BESI – 4 million (2S) events.

The ratios of the studied BRs to that for B(’ π+π- J/ ), So systematic errors with same source between two BRs are cancelled.

10 ’ VP decay channels are measured, many other multi-body decays are studied. “12% rule” is tested extensively.

Observation of ρπ and K*K.S- D-wave charmonia mixing model is tested in ρπdecay mode, data agree with prediction well. This may supply a way to explain the 12% rule violation.

´ρπ, ’’ρπ,.Ψ´EM and hadronic transition are studied.

BRs are measured

Summary

Thanks a lot Thanks a lot !!

BES results of ΧcJ

parameters and decays measuremen

t.

backup

ΧcJ parameters, Inclusive e+e- spectrum

c2

c1

c0data

Bkg subtract

Mass (MeV):c0=3414.21±0.39±0.27c1=3510.30±0.14±0.16c2=3555.70±0.59±0.39Width (MeV):c0=12.6±1.6±1.0c1=1.39±0.40±0.77

Paper Acceptedhep-ex/0502031Invariant mass of two electrons converted from photons.

At BES, the momentum resolution for charged tracks in MDC (σp/p=1.7%/1+p2) is much better than its energy resolution for the photons in BSC(E/E= 22 % ), So BES use a method of gamma

conersion in detector (e+e- ) to obtain the inclusive gamma spectrum in Ψ´ decays.

Results of Hadronic decays of cJ

Hep-ex/0410028

PRD70, 092002 (2004)

PRD70, 092003 (2004)

Many measurements are first observations!

Useful for understanding the decay dynamics and testing the new QCD approach

including the effect of the Color Octet Mechanism(COM, …).

Mode c0 (10 – 4) c1 (10 – 4) c2 (10 – 4)

KS KS 35.1±2.2±4.7 <0.8 @ 90% C. L. 8.9±1.2±1.3

+–KS KS 65±6±10 8.0±3.1±1.4 32.4±6.1±5.5

K+K–KS KS 16.0±4.6±2.9 <5.1 @ 90% C. L. <5.5 @ 90% C. L.

f0(980) f0(980) 7.6±1.9±1.6 - -

K*0K*0 17.8±3.4±3.4 16.7±3.2±3.1 48.6±5.6±8.8

22.9±5.8±4.1 - 17.7±4.7±3.6

Search for muti-quark state using Ψ´ data

Not observe pentaquark in BES data

50

50

101.1.)./(

1084.0.).'(

ccnpKKJB

ccnpKKB

S

S

’ J/

PRD70, 012004 (2004)

Search for Ψ´(J/Ψ)Θ decays

MC

MC

N*

R(2000)

J/ bkg

Dalitz analyses for ’pp0, pp

PRD71, 072006 (2005)

N*(1440, 1520,1535), no clear N*(2065)?

PRD71, 072006 (2005)

Ppbar inv. Mass of selected ppπ0(η) events. (Enhancements around 2 GeV/c2 in two channels, not same since they have

different isospin)

Pπ (pη) inv. Mass after removing Ψ´J/Ψ+X bg.

All the signals are not significant, All the signals are not significant, more statistical is needed.more statistical is needed.

σ Search in Ψ´π+π-J/Ψ

BES P rel im

inaryσ search in ’+-J/

~ 40,000 evts

Pole position is consistent with the PWA result of J/Ψωπ+π-

(54139)-i(25242) MeV

Phys.Lett.B598:149-158,2004

BESII .VS. CLEO-cVP mode

Upper limit @90 ％ C.L.

• Most channels BRs are consistent.

• BES BR()>CLEO by ~ 3 because the different treatment of continuum BG. and the interference between ρ(770) and its excited state in PWA.

• BR(K*0K0) are deviated (different treatment of the continuum contribution)

IHEP Zheng Wang

’ VP: comparison with CLEOc results

• Most channel consistent.• (770) BES > CLEO ( ~ 2.5) fit vs cut and destructive interference.

BESII

CLEOc

Comparisons of Comparisons of ' results' results

Study of psi(2S) decays to X J/psi. Phys.Rev.D70:012003,2004; hep-ex/0404020

CLEOc(%)

E835(%)

BES(%)

PDG04Fit(%)

B(' → 0 0 J/ )B(' → + - J/ )

49.240.470.8657.1

1.84.457.0

0.92.659 5

B(' → η J/ )B(' → + - J/ ) 9.68 0.190.13 9.5 0.70.7 9.8 0.51.0 10.0 0.8

B(' → + - J/ )B(' → X J/ )

56.370.270.4652.50.92.

253.60.81.

654.9 1.1

B(' → χc1 → J/ )B(' → + - J/ )

10.24 0.170.23

12.6 0.33.8

8.4 0.6

B(' → χc2 → J/ )B(' → + - J/ )

5.52 0.130.13 6.0 0.02.8 3.0 0.4

BES

Comparisons of Comparisons of ' results' results

Psi(2S) decays into J/psi plus two photons. Phys.Rev.D70:012006,2004; hep-ex/0403023

CLEOc(%)

BES(%)

PDG04Fit(%)

B(' → 0 J/ ) 0.130.010.010.1430.0140

.0120.096 0.021

B(' → η J/ ) 3.25 0.060.11

2.980.090.23

3.160.22

B(' → χc1 → J/ ) 3.44 0.060.13

2.81 0.050.23

2.67 0.15

B(' → χc2 → J/ ) 1.85 0.040.07

1.62 0.040.12

1.30 0.08

BES

outline

(2S)0J/,0

(2S)J/,

(2S)c1 , c1 J/

(2S)c2 , c2 J/

J/(BES-II data)

X+J/

(BES-I data)

(2S)J/

(2S)J/

(2S)c1 , c1 J/

(2S)c2 , c2 J/

J/e+e ， +

J/+

’ J/ Discussions

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

mm

f

AB

mm

f

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

BES (+PDG for ):

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

Casalbuoni et al: give an improved expression

[PLB 309,163(1993)], but A and B are unknown

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

B/A=-1.420.12

B/A=-3.11 0.15