experimental results in charmonium decays from bes
DESCRIPTION
Experimental results in charmonium decays from BES. Rong-Gang Ping (presented by F. Harris) for BES collaboration Charm 2007 Aug. 6, 2007. (2s) data samples. outline. ’ decays Leptonic decays Radiative decays Hadronic decays cJ decays VV PPP. 26M. 14M. 4M. 3M. - PowerPoint PPT PresentationTRANSCRIPT
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 !