Experimental results in charmonium decays from BES

Rong-Gang Ping

(presented by F. Harris)

for BES collaboration

Charm 2007

Aug. 6, 2007

0

5

10

15

20

25

30

MKI MKII MKIII CBAL BESI BESII CLEO CLEOc

(2s) data samples’ decays

Leptonic decays

Radiative decays

Hadronic decays

cJ decays

VV

PPP

3M

14M

4M

outline

26M

Also 6.42 pb-1 of data at Ecm=3.65 GeV for background study.

Expected? Sequential lepton hypothesis:

BESII: remeasure with larger sampleMeasured in ee

Characterized by•2 charged tracks; 1 and 1 e•missing energy and momentum•no extra hits in BSC

= 17.8%

BESII Result:

B( ) = (3.100.210.38) x 10-3

Bee (10-3) B (10-3) B/0.3885 (10-3)

7.35 0.38 7.3 0.8 8.0 1.1

Lepton universality is tested in charmonium decays.

PRD 74: 112003 (2006)

decays radiative S2

)(2)3(:prong-6 -

..),,2(pp)2(:prong-4 -

,pp :prong-2 -

X)2Br(

modes more Measure

)2003(032004,672-

101(1998)][PRD58,097 -

BESIby measured modes limitedOnly '

ccKKKK

S

PRDS

S

S2 Background

data

Bg

bg

2bgbg

2sigs

2obs ww

S2

bg.other 3.

hadrons hadrons,

processes, photo-multi 2.

processes QED 1.

including Background

signal bg.n Bg. QED others

’ radiative decays PRL 99, 011802 (2007)

Observation of ’ radiative decays

Mode BR (10-5)[m<2.9 GeV/c2]

pp-bar 2.9 ± 0.4 ± 0.4

’ 12.6 ± 2.9 ± 1.5

2(+-) 39.6 ± 2.8 ± 5.0

KSK+-+c.c. 25.6 ± 3.6 ± 3.6

+-K+K- 19.1 ± 2.7 ± 4.3

+-ppbar 2.8 ± 1.2 ± 0.7

2(K+K-) < 4.0

3(+-) < 17

2(+-)K+K- < 22

• Expect ~1% BR, but only 0.05% previously observed.• Potential channels for hadron spectroscopy study, including search for non-qqbar

states, if enough statistics.• ~ 0.1% more observed in this analysis.

PRL99, 011802 (2007)

PRD74, 072001 (2006).

PRD74, 072001 (2006).

K*K

ρπ

MARK-II

tested.rule" "12%

observed.symmetry SU(3) sample. data 2larger

a with BR remeasure BESI,by t measuremenFirst

S

)c/GeV(m 2

p

00

)c/GeV(m 2

p

)c/GeV(m 2

p

x 10-4 x 10-4

Angular distribution:2

Baryonic decays

Rich structure (N*s), statistics (~850 evts in each mode). Still low for a partial wave analysis.

PRD74, 012004 (2006)

2006 062001, PRL97,

obtained events 000,100

../ ccnpJ

27.091.1:27.086.1:1)'(:)'(:)'( 0 npBnpBppB

Test I-spin symmetry(prediction: 1:2:2)

PRL 99,011802 (2007)

cJ→2(K+K) Improved precision over PDG (BESI) results on cJKKKK and .

First measurement of cJKK.

c2

c0 c1

Pair production of vectorsPLB642, 197 (2006)

PRD 74, 072001 (2006)

c2

c1

c0→PPP is suppressed by spin-parity selection;

cJ decays into PPP PRD74, 072001 (2006) cJ→KK and

c1→KSK+-+c.c.

K*

Nsig=418± 60

Nsig=58± 14 (4.5)Nsig=222±28 (8.8)

sidebanda sideband

c1→ +-

BES: cJ→KK and PRD 74, 072001 (2006)

CLEO-c, PRD75, 032002

’(J/) +0/• Is it really B(0)>B()?

arXiv: 0707.1127 [hep-ex]Submitted to PRD

First measurement!

background fromJ/ ΣΛπ

signal

’ leptonic decays, hadronic decays, radiative decays are studied to search for new phenomena and to test QCD predictions.

c decays are studied using ’ data sample.

CLEOc will take the leading role in ’ and c

decays; we are now preparing for the BESIII data taking and the physics analysis.

Summary

Thanks a lot !