Post on 18-Mar-2021
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.