J/ψ and ψ’ physicsat BESII

Ping Wang

(Representing BES Collaboration)

Institute of High Energy Physics, CAS, China

QWG, June 27-30, 2006, BNL

Scalars: σ, κ, f0(980), f0(1370), f0(1500), f0(1710), f0(1790) …

Possible bound state in The ωφ threshold enhancement in J/ψ → γωφStudy of J/ψ → γωωNew observation of a broad 1- - resonance in J/ψ → K+K- π0

J/ψ physics:

pp ppJ γψ →/

ψ’physics

ψ’→ VP

ψ’→ 3-body

EM form factor of ωπ

χ cJ Decays

ψ(3770) physics

The non-Ddbar decays of ψ(3770)

The σ pole in at BESII−+→ πωπψ/J

M(γγ)M(π+π-π0)

M(π+π-)

π0ω

σ σ

Averaged pole position: (541 39) (252 42)i± − ± MeV

Phys. Lett. B 598 (2004) 149

κ

24872

8173 MeV/c )45309()30841( +

−+− ±−± i

Phys. Lett. B 633 (2006) 681

Observation of an anomalous enhancement near the threshold of mass spectrum at BES II

M=1859 MeV/c2

Γ < 30 MeV/c2 (90% CL)

J/ψ γpp

M(pp)-2mp (GeV)0 0.1 0.2 0.3

3-body phase space acceptance

χ2/dof=56/56

acceptance weighted BW +3 +5

−10 −25

pp

BES II

Phys. Rev. Lett. 91, 022001 (2003)

Observation of X(1835) in

The π+π-η′ mass spectrum for η′ decaying into η′→π+π-η and η′→ γρ

Statistical Significance 7.7 σ

ηππγψ ′→ −+J

ηππγψ ′→ −+J

Mass spectrum fitting

54264 ±=obsN

MeVm 7.21.67.1833 ±±=

MeV7.73.207.67 ±±=Γ

410)4.04.02.2()()( −−+ ×±±=′→→ ηππγψ XBXJB

7.7σThe π+π-η′ mass spectrumfor η′ decaying into η′→π+π-η and η′→ γρ

BESII Preliminary

59.18.0 10)4.00.7()()(:.. −+

− ×±=→→ ppXBXJBfc γψ

Re-fit to J/ψ γp pbar including FSI

Include FSI curve from A.Sirbirtsev et al. ( Phys.Rev.D71:054010, 2005 ) in the fit (I=0)

M = 1830.6 ± 6.7 MeV

Γ = < 153 MeV @90%C.L.

ppp mM 2−

In good agreement with X(1835)

Observation of ωφ thresholdenhancement in J/ψ → γωφ

) ,( 0 −+−+ →→ KKφπππω

OZI DOZI −+→→ KKJ φγφφψ ,/ γωφψ →/J

M(π+π-π0)

M(K

+ K- ) ωφ

φφ

M(K+K-)

φ

MeVMMKK

15|| <−φ

MeVMMMeVKK

35||20 <−<φ

ω

φ

M(π+π-π0)

Dalitz plot

Clear φ and ω signals

M2(γω)

M2 (

γφ)

A clear threshold enhancement is observed

φωEff. curve

Phase Space

Side-bands

Side-bands do not have mass threshold enhancement!

The decay of J/ψ→γωφ is observed and an enhancement in ωφ is found near the threshold.

PWA shows: the enhancement favors 0++

.

2

21926

MeV/c 2820105

MeV/c 181812

±±=Γ

±= +−M

410)65.027.061.2()()/( −×±±=→⋅→ ωφγψ XBrXJBr

Phys. Rev. Lett., 96 (2006) 162002

0 /

πππω

γωωψ−+→

→J

M(π+π-π0)(GeV/c2) M(π+π-π0)(GeV/c2) M(π+π-π0)(GeV/c2)

M(π

+ π- π

0 )(G

eV/c

2 )ωω

ω sideband

BES II Preliminary

ω signal after best candidate selection

(best ω masses)

ω signal with multiple entries

Eff. curvePhase Space Side-band

M(ωω) M(ωω)

dominated by η(1760)a 0++ is possible needed (6.5 σ)

Accepted by PRD, hep-ex/0604045

3-

22421

2

100.32)0.08(1.98 ))1760(())1760(/(

MeV/c 25244MeV/c 15101744

×±±=

=→→±=Γ

±±=+−

ωωηγηψ BrJBr

M

New observation of a broad 1- - resonance in J/ψ → K+K- π0

0π

η

J/ψ → K+K- π0

very clean π0 signal

)1580(X

Background

0π

±)890(*K

)1580(X

±)1410(*K

J/ψ → K+K- π0

PID and kinematic fit can significantly reducethe dominant background from J/ψ → π+ π- π0.

Four decay modes are included :

Amplitudes are defined byCovariant tensor formalism

B.S. Zhou and D.V. Bugg, Eur. Phys. J. A16, 537(2003)

BW with energy-dependent width

J.H. Kuhn, A. Satamaria, Z. Phys. C48, 445 (1990).

fitPWA :hist data : points

0*

0*

)1410( )890(

: 1

π

π±±

±±

−

→

→

KKKK

component

)1410( ),890( )(,)(/

),( ,))1700(,(/

***

0**0

KKKwhereKKKKJ

KKXXJ

=

→→

→→±±±

−+

πψ

ρπρψ∓

122

22

2

))(

)(()()(

;)(

1)(

+Γ=Γ

Γ+−=

l

R

RRRR

RR

Mpsp

sMMs

ssiMssBW

PSKK

KKXcomponent

−+

−+

−−

→

→

)1700(

: 1

ρ

Partial Wave Analysis of J/ψ → K+K- π0 events

Parity conservations in J/ψ → K+K- π0 requires thatspin-parity of K+K- should be 1--,3--,…

PWA fit with andphase space (PS) gives ( preliminary ):

( can be ruled out by much worse likelihood )

X pole position

big destructive interference among and PS

−−=1PCJ

)1410( ),890( (1700), , ** KKX ρ

232116712

98499155 / )(409 )1576( cMeVi ++

−−++−− −

47.26.3

0 10)6.05.8()()/( −+−

−+ ×±=→⋅→ KKXBrXJBr πψ

(1700) , ρX

−−3

Partial Wave Analysis of J/ψ → K+K- π0 events

Angular distributions for events withfrom PWA fit

2/ 7.1 cGeVM KK <−+

Figures on the right:(a),(c),(e) are polar anglesin lab. reference frame(b),(d),(f) are polar anglesin CM frames of

respectively

fitPWA :hist data, : points

−+± KKandK 0π

Broad X cannot be fit with known mesons or their interferenceIt is unlikely to be ρ(1450), because:

The parameters of the X is incompatible with ρ(1450).

ρ(1450) has very small fraction to KK. From PDG:

It cannot be fit with the interference of ρ(770) , ρ(1900) and ρ(2150):

The log-likelihood value worsens by 85 (Δχ2=170).

.).%95( 106.1))1450(( 3 LCKKBr −−+ ×<→ρ

ψ’physics

ψ’→ VP

ψ’→ 3-body

EM form factor of ωπ

χ cJ Decays

BESII229 π0s

π+ π- π0

50 101.9)1.8(18.1)πππB(ψ' −−+ ×±±=→

BESII

BESII: PLB619, 247 (2005)

[ ][ ] 5

3.4

5

10)2.5(19.4ρ(2150)πψ'B

101.1)0.7(5.1ρ(770)πψ'B11.5 −

−

−

×±=→

×±±=→+

Very different from J/ψ→3π!

J/ψ

ψ’

PWA

ψ’→ VP

ψ’→ VP K*(892)K +c.c.

K*± K*2(1430)

B.G.

K*0

9.6±4.2Evt. 3.5σ

65.6±9.0Evt. 11σ

Br±(2.9±1.7±0.4)×10 –5

Br0(13.3±2.8±1.7)×10 –5

K*±

K*0

K*2(1430)

B.G.

BESII: PLB614, 37 (2005)

@ ψ’Large IsospinViolation Br0/ Br±=4.6±2.8@ J/ψBr0/ Br±=0.8±0.1

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

modeBESII:

B(ψ’)(×10-5)CLEOc:

B(ψ’)(×10-5)PDG04/BESII/…

B(J/ψ)(×10-4)B(ψ’)/B(J/ψ)

(%)ρπ 5.1±0.7±1.1 2.4+0.8

-0.7±0.2 234±26N/A

200±950±442±4

5.38±0.661.93±0.231.05±0.18

<0.0648.98±0.925.46±0.6423.5±2.7

2.26±0.43

0.13±0.03ρ(2150)π 19.4±2.5+11.5

-3.4 N/A N/Aπ+π-π0 18.1±1.8±1.9 18.8+1.6

-1.5±2.8 0.92±0.11K*+K-+c.c. 13.3±2.7±1.7 9.2+2.7

-2.2±0.9 0.34±0.20K*0K0+c.c. 2.9±1.7±0.4 1.3+1.0

-0.7±0.3 2.6±0.6ωπ 1.87+0.68

-0.62±0.28 2.5+1.2-1.0±0.2 3.7±1.2

ρη 1.78+0.67-0.62±0.17 3.0+1.1

-0.9±0.2 10.9±3.4ρη’ 1.87+1.64

-1.11±0.33 N/A 18±16φπ <0.40 N/A N/Aφη 3.3±1.1±0.5 2.0+1.5

-1.1±0.4 3.0±1.2φη’ 3.1±1.4±0.7 N/A 5.7±3.0ωη <3.1 N/A <0.53ωη’ 3.2+2.4

-2.0±0.7 N/A 14±11

† MARKII:PRD29,804(1984); ‡ PDG04. Suppressed!!

ψ’→ 3-body

mode Bψ’ →X (10 – 4) B J/ψ→X (10 – 3) Qh(%)

2.02 ±0.17 † 12.1 ±1.6

13.1 ±1.8

12.1 ±1.9

2.8 ±0.7

1.93 ±0.17 †

1.09 ±0.09 ‡

2.09 ±0.18 ‡

pnπ – 2.45 ±0.11 ±0.21

pnπ + 2.52 ±0.12 ±0.22

ppπ 0 1.32 ±0.10 ±0.15

ppη 0.58 ±0.11 ±0.07

BESII: PRD71, 072006 (2005)BESII: hep-ex/0605031

B(ppπ0): B(pnπ –): B(pnπ+)=1: (1.86±0.27) : (1.91±0.27 ) ≈ 1:2:2Yuan, Mo,Wang: PLB626, 95(2005)

ψ’→VP and PP BESII: PRD70, 112007 (2004)

-

Form Factor Measurement

A: PLB425(1998)365

B: hep-ph/9906387

Form Factor Measurement

A: PLB425(1998)365

B: hep-ph/9906387

sFF CLEOBES /⋅= 2

F(π+π− )

F(K+K– )

1. ΣQi = 0 ; 2. p(π+)+p(π − ) > 650 MeV [BG:Ψ’ π+ π− J/ Ψ]; 3. Prob( γ π+ π− K+ K− )>

Prob( γ π+ π− π+ π− )&Prob( γ π+ π− K+ K− )>

Prob( γ K+ K− K+ K− );4. M(π+ π−) ⊂ [497±50] MeV/c2

& second vertex <5mm [BG: KS ];

Event level

χc0 → π + π − K + K −

1.Avoid introducing a huge number of partial waves;2. constrained by present statistics; our study is devoted to χc0 → π + π − K + K −

1371 events

χc0

χc1(3511.3±1.3MeV)χc0(3414.7±0.6MeV)

χc2(3556.4±0.9MeV)

5C-fit

BES: PRD72, 092002 (2005)

Summary PWA of χc0 → π + π − K + K −

From the χc0 → π + π − 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.

BES: preliminaryχcJ→2(K+K−)

Improved precision over PDG (BESI) results on χcJ KKKK and φφ.

First measurement of χcJ φKK.

χc2

χc0 χc1

Pair production of vectorsχcJ φφ

BES: PLB630, 7 (2005)

First observation:B(χc0 ωω) = (2.29±0.58±0.41)×10-3

B(χc2 ωω) = (1.77±0.47±0.36)×10-3

28χc2

38χc0

Pair production of vectorsχcJ ωω

BES: preliminary χcJ→KKπ and ηππχc0→PPP is suppressed by spin-parity selection;

χcJ →ηπ+π-

hep-ex/0605031

χc0 χc1 χc2

hep-ex/0605031

BES: PRD73, 052006 (2006)

χc0

Λ

Ξ

χcJ ΞΞ

Evidences for χc0 ΞΞ and χc0,2 ΛΛππ.

.

ψ(3770) physics

The non-Ddbar decays of ψ(3770)

00DD

−+DD

Inclusive hadrons

Branching fractions

)%8.27.39.36())3770(( ±±=→ −+ DDBF ψ

)%3.27.47.46())3770(( 00 ±±=→ DDBF ψ

)%2.43.76.83())3770(( ±±=→ DDBF ψ

)%2.43.74.16())3770(( ±±=−→ DDnonBF ψ

Obtained from fitting to the inclusivehadron and the DD-bar production cross sections simultaneously.

where the first error is statistical and second systematic, which arises from the un-canceled systematic uncertainties inhadron cross sections (~4.4 %), neutral DD-bar cross sections (~4.5 %) and charged DD-bar cross sections (~7.4 %).

hep-ex/0605107

These results are preliminary !

Born)3770((3770) & R ψψ σ

udsEcm RERRcm

−= = GeV 3.773)3770( |)(ψ

Taking the R for light hadron production to be a constant, then

13.004.057.1)3770( ±±=ψRWe obtain

nb 81026.058.9Born)3770( .±±=ψσ

nb 74.108.11))3770(()1(

122

)3770(VP

Born)3770( ±=→×

+= −+ eeBF

Mψ

δπσ

ψψ

)024.0047.1()1( VP ±=+ δobtained based on PDG04 ψ(3770)resonance parametersPLB 603(2004)130

My

calc

ulat

ion It is consistent with

)non)3770(( DDBF −→ψ determined with DDσR &

Preliminary

Including ψ(3770)

hep-ex/0605105

preliminary

)%3.31.10.35())3770(( ±±=→ −+ DDBF ψ)%8.32.19.48())3770(( 00 ±±=→ DDBF ψ

)%7.56.19.83())3770(( ±±=→ DDBF ψ

)%7.56.11.16())3770(( ±±=−→ DDnonBF ψ

Results of branching fractionsWith BES previously measured cross sections for DD production.

PLB603(2004) 130

hep-ex/0605105

These result in the non-DD branching fraction

Summaryσ and κ are studied

the observation of ωφ threshold enhancement f0(1810) in J/ψ → γωφ

η(1760) dominant in J/ψ → γωω, possible

existence of f0 at around 1800 MeV.

Summary

New observation of a broad 1- -

resonance in J/ψ → K+K- π0

new measurement of ψ’→ VP andψ’→ 3-bodyEM form factor of ωπ measured at three energies

c cJ decays studied

BES measured the branching fractions for inclusive non-DD-bar decays of ψ(3770) using two different data samples and two different methods

.(preliminary !)

SUMMARY

)%3.31.10.35())3770(( ±±=→ −+ DDBF ψ)%8.32.19.48())3770(( 00 ±±=→ DDBF ψ

)%7.56.19.83())3770(( ±±=→ DDBF ψ)%7.56.11.16())3770(( ±±=−→ DDnonBF ψ

Determined from analysis of R values and DD-bar cross sections

)%8.27.39.36())3770(( ±±=→ −+ DDBF ψ)%3.27.47.46())3770(( 00 ±±=→ DDBF ψ

)%2.43.76.83())3770(( ±±=→ DDBF ψ)%2.43.74.16())3770(( ±±=−→ DDnonBF ψ

Obtained from fitting to the inclusive hadronand the DD-bar production cross sections simultaneously.