Exotic Hadrons( 奇特强子态 )

Changzheng YUAN ( 苑长征 )(BES & Belle Collaborations)

中国科技大学2009 年 10 月 23 日

2

Hadrons： normal & exotic

• Hadrons are composed from 2 (meson) or 3 (baryon) quarks

Quark model

• QCD allows hadrons with Nquarks2, 3– glueball ： Nquarks = 0 (gg, ggg, …)– hybrid ： Nquarks = 2 + excited gluon– Multiquark state ： Nquarks > 3 – molecule ： bound state of more than 2 hadrons

3

A bit of history on exotics hunting

• “The absence of exotics is one of the most obvious features of QCD” – R. L. Jaffe, 2005

• Deuteron H state, d’, d*, -- bound state• No solid signature of glueballs• Pentaquark state appeared and disappeared (“The story of pentaquark shows how poorly we

understand QCD” – F. Wilczek, 2005)• Do we still have hope?

Yes!

4

Outline

The XYZ states at B-factories + other experiments XYZ charmonium + light meson• X(3872) – molecular state?• XYZ(3940) & X(3915) – charmonia?• Y(4140) & X(4350) – tetraquark states?• Y states in ISR – hybrids?• Z+(4430)/Z+(4050)/Z+(4250) – cannot be charmonia! (1S)+X/Y – new results from Belle!• Opportunity at BESIII and other experiments.

5

Most of the XYZ from B-factories

+ BES, CDF, D0

6

Charmonium spectroscopyM

ass (

MeV

)

JPC

(2S+1)LJ

Open charm threshold.

(3770)

(4040)

(potential Models)c

’c

J/

’ c2 c1 c0hc

(4415)

We were very pride:

Potential models worked well for charmonium.

No big progress in last century!

(4160)

hc

7

Then we found lots of XYZ states

M(M

eV

)

JPC

(2S+1)LJ

Open charm threshold (3770)

(4040)

(4160)

(potential Models)c

’c

J/

’ c2 c1 c0

X Z Y

X(3872)

(4415)

XYZ(3940)

X(3915)X(4160)Y(4008)Y(4140)Y(4260)Y(4360)X(4350)Y(4660)

X(3915)X(4160)Y(4008)Y(4140)Y(4260)Y(4360)X(4350)Y(4660)

Z(4430)Z(4250)Z(4050)

Y(4140)

What are they ?

Charmonium?Hybrid?Tetraquark?Molecule?…

Not all XYZ states are charmonia!

hc

?Y

8

X(3872)

first and most puzzling state(observed in 2003 at Belle)

9

X(3872) J/arXiv:0809.1224 605 fb-1

= (2.7±1.6±0.4) MeV

PRD77,111101 (2008) 413 fb-1recent results

B±XK±

B0XK0

Ns=93±178.6

Ns=9±52.3

10

X(3872) J/in CDFrecent results

arXiv:0906.5218

~6000 events!

MX = 3871.61 ± 0.16 ± 0.19 MeV

MX < 3.6 MeV @ 95% CL

Fits for 2 nearby states

11

M(X(3872)) J/ mode only

new CDF meas.PRL103, 152001

new Belle meas.

MD0 + MD*0.

<MX>= 3871.46 ± 0.19 MeV

m = -0.35 ± 0.41 MeV

BES III canimprove on this

No sign of a mass doublet a la Maiani et al

m(deuteron) = -2.2 MeV

PRL103, 152001 (2009)

12

Mass in X3872 D*0D0

414fb-1

D0D00

Belle 2006, 414/fbX3872 D0D00

BaBar 2006, 347/fbX3872 D0D*0(0D0,D0)

Fit with truncated BW in both exps.

Is this the higher mass partner state predicted by Maiani et al?

13

Belle update 605fb-1

D0D*0(D0

605fb-1

D0D*0(D00)

Fit with a phase-space modulated BWCan also use other parameterizations to do the fit

Nsignal= 48±11 evts

Signif.=8.8

Agree with J/ mode.

14

X(3872)J/ & ’ from BaBar

X(3872) J/ X(3872) S

BABAR BABAR

PRL 102, 132001 (2009)

3.0 3.5

Bf(B+X3872K+)×(X3872J/)=(2.8 ± 0.8 ± 0.2) × 10-6

Bf(B+X3872K+)×(X3872’)=(9.5 ± 2.7 ± 0.9) × 10-6

• C-parity = +1 (Belle also measured J/: 0505037)

• JPC = 2 -+ disfavored multipole suppression

•Bf(X3872’) > Bf(X3872J/) bad for moleculesSwanson PLB 598, 197 (2004)

15

BKX(3872) from Belle

arXiv:0809.1224 605 fb-1

~90 events

Very w

eak K*(8

90)

M(K) in GeVM(J/) in GeV

Backgrounds from J/ sidebands

Bf(BJ/ K*0)/Bf(BJ/ KNR) ~ 4. Similar ratios for c1, (2S)!

X is very different from other charmonia. Pure 3-body B decays? Check Dalitz plot!

16

Production of X(3872) in B decaysProduction of X(3872) in B decays

L. C. 90%at 102.3)3872( 4 KXBBf

17

Decay of X(3872)Decay of X(3872)

%3.2/

gets one

102.3)3872(

on limit upper Babar ith Together w

1093.020.8/,)3872(

:average (2008) Belle and (2008)Babar

4

6

JXBf

KXBBf

JXKXBBf

18

Decay of X(3872)Decay of X(3872)

L. C. @90% %6.611675.98.22.82.8

12.8)/(

...

10)47.036.067.1(.).()(

10)9.07.25.9())2(()(

10)2.08.08.2()/()(

10)2.42.8()/()(

10)93.020.8()/()(

4*00

6

6

60

6

JXBf

ccDDXBfXKBBf

SXBfXKBBf

JXBfXKBBf

JXBfXKBBf

JXBfXKBBf

L. C. 90%at 102.3)3872(104.1

%6.6/2.3% 44

KXBBf

JXBf

4

41

4

108.03.14.8

107.04.10.8

104.06.19.4)2(

KBBf

KBBf

KSBBf

c

c

19

X(3872) summary• Mass: Very close to D0D*0 threshold• Width: Very narrow, < 3 MeV• JPC=1++ favoured • Production

– in pp collison – similar to charmonia– In B decays – KX similar to cc, K*X smaller than cc

• Decay BR: open charm ~ 50%, charmonium~O(%)• Nature (very likely exotic)

– Loosely D0D*0 bound state (like deuteron?)?– Mixture of excited c1 and D0D*0 bound state?– Many other possibilities (if it is not c1, where is c1?)

20

The states near 3940 MeV -circa 2005-

M = 3942 +7 ± 6 MeV tot = 37 +26 ±12 MeV Nsig = 52 +24 ± 11 evts

-6

-15

-16

PRL 100, 202001

e+e- J/ DD*

M(DD*)M≈3940 ± 11 MeV≈ 92 ± 24 MeV

PRL94, 182002

M(J/)

BKJ/

M = 3929±5±2 MeV tot = 29±10±2 MeV Nsig = 64 ± 18 evts

DD

M(DD)

PRL 96, 082003

X(3940) Y(3940) Z(3930)

not seen in J/ not seen in DD* Probably the c2’probablydifferent

BaBar: PRL 101, 082001

M≈3914 ± 5 MeV≈ 33 ± 10 MeV

21

New peak in J/

X

M: 3914 3 2 MeV, : 23 10 +2 -8 MeV,

Nres = 55 14 +2 -14 events

Signif. = 7.7,

prel

imin

ary

Background only fit

22

Could it be the Z(3930)?

M: 3914 3 2 MeV,

: 23 10 +2 -8 MeV,

Nres = 55 14 +2 -14 evts

M = 3929±5±2 MeV tot = 29±10±2 MeV Nsig = 64 ± 18 evts

DD

J/

23

partial width

B(J/) = 69 16 +7 eV (JP=0+)

B(J/) = 21 4 +2 eV (JP=2+)

For comparison:: B(DD) = 180 50±30 eV

If X(3915) = Z(3930) = c2’ 0.08B(c2’J/)

B(c2’DD)

Huge for above-open-charm-threshold charmonium

-18

-5

24

The 4 states near 3940

X(3940)Y(3940)

Belle

Z(3930)

Mass(GeV)

This X(3915)

Width(GeV)

Range: ((stat.)(sys.))

Good overlap withBaBar “Y(3940)” values

25

cc assignments for X(3915), X(3940) & Y(3940)?

3940MeV

•Y(3940) = X(3915) = co’ ? (J/) too large?•X(3940) = c”? mass too low? (3S)=4040 MeV•Z(3940) = c2’ ? (M(J=2,0)=15±7 MeV?)

c”

c’’’

3915MeVc0’

States decaying into J/

Evidence for Y(4140) and a New Resonance at 4.35 GeV

27

The CDF Y(4140)J/• B+Y(4140)K+

• 14±5 events, >3.8• Mass: 4143.0 ± 2.9 ± 1.2 MeV• Width: 11.7+8.3

-5.0 ± 3.7 MeV (It is narrow!)

PRL102, 242002 (2009)

D*D*ssDD**ss molecule? molecule? [cs[cscscs] tetraquark?] tetraquark?

28

Belle: B→J/ψK with 772M BB M(J/ψ) fit with Y(4140) parameters fixed [but low effciency at J/ threshold]

Y(4140) not significant at Belle

21325

/

KJB

2sBEE

6109.24.30.9

/,)4140(

:result CDF

JYKYBBr

LC

JYKYBBr

.%90@106

/,)4140(6

J/ψM

Preliminary Preliminary 9.15.7 9.44.4

29

Searched for in J/

• No Y(4140) • A few events ac

cumulate at 4.35 GeV in both J/ee and modes

preliminary

825 /fb

JP=0+: ΓγγBr(Y(4140)) →J/) < 39 eV @ 90% C.L.JP=2+: ΓγγBr(Y(4140)) →J/) < 5.7 eV @ 90% C.L.

30

Y(4140)= Ds*+Ds

*- molecule?

• Molecule state disfavored.

JP=0+: ΓγγBr(Y(4140)) →J/) = 176+137-93 eV

JP=2+: ΓγγBr(Y(4140)) →J/) = 189+147-100 eV

T. Branz et al., PRD80, 054019 (2009): if Y is Ds*+Ds

*- molecule

31

Fit to J/ invariant mass

• unbinned maximum likelihood method

• BW convoluted with Double Gaussian resolution function

• mass resolution is 5.5 MeV at 4.35 GeV

prel

imin

ary

S.S.=3.9, const. bkgS.S.=3.2, linear bkg

JP=0+: ΓγγBr(X(4350)) →J/) =6.4+3.1-2.3 ± 1.1 eV

JP=2+: ΓγγBr(X(4350)) →J/) =1.5+0.7-0.5 ± 0.3 eV

825 /fb

32

Preliminary results• M(X(4350))=4350.6+4.6

-5.1± 0.7 MeV/c2 • Γ=13.3+17.9

-9.1 ± 4.1 MeV/c2 • N (X(4350))=8.8+4.2

-3.2

• Statistical significance: 3.2-3.9

• Excited P-wave charmonium? • Tetraquark? Fl. Stancu, arXiv: 0906.2485• D*

sD*s0 molecule at

4.34±0.09 GeV? J.R.Zhang et al., arXiv:0905.4672

825 /fb

33

R values/ states/Y states

The Y states should also appear inthis plot (between 4.0 and 4.7 GeV!)

From PDG

} JPC = 1--

’, ’’, Y…

)(

)(

ee

hadronseeR

34

Y family (vector states)e+e-→J/ψπ+π- γISR e+e-→ψ(2S)π+π- γISR

Above DD threshold, decay to open charm?

PRL 99, 182004 (2007) PRL 99, 142002 (2007)

550 fb-1

Y(4008) 7σ

Y(4260)

Y(4360) Y(4660) 6

670 fb-1

arXiv:0808.1543

Y(4260)

454 fb-1

Y(4008) ?

M(J/M(J/ψππψππ)) M(M(ψψ(2S)(2S)ππππ))

Y(4360)298 fb-1

Y(4660) ?

PRL 98, 212001 (2007)

35

Y family Y(4008), Y(4260), Y(4360), Y(4660) don’t match peaks in D(*)D(*) Xsection Widths for ψππ transition too large for conventional charmonia Y(4260) is DD1 molecule/ccg hybrid?

DD1 [→ DD*π] decay should dominate but no signal found

D*D*

DD*

(4

040)

(4

160)

Y(4

008)

(4

415)

Y(4

660)

Y(4

260)

Y(4

350)

DD

DDπ

Λc+Λc

–

?

PRD77,011103(2008)

PRL100,062001(2008)

PRL98, 092001 (2007)

PRL101, 172001(2008)

ee++ee--→open charm →open charm γγISRISR

M=4630M=4630Y(4660) ?Y(4660) ?

0908.0231[hep-ex]

DD*πY(4260) ψ(4415)

9

/4260

4260*

JYBr

DDYBr

M(DD*)

36

What are the Y states?• Between 4 and 4.7 GeV,

at most 5 states expected (3S, 2D, 4S, 3D, 5S), 7 observed

• Hybrids are expected in this mass region

• Molecular states?• Cannot rule out thresh

old effect/FSI/…• Y(4260), Y(4360), Y(466

0) are all narrow and similar

37

Charged state with hidden charmZ+(4430) and more

Unambiguous tetraquark state?

38

Z(4430)±→ψ(2S)π±

Found in ψ(2S)π+ from B→ψ(2S)π+K. Z parameters from fit to M(ψ(2S)π+) Confirmed through Dalitz-plot analysis of B→ψ(2S)π+K B→ ψ(2S)π+K amplitude: coherent sum of Breit-Wigner contributions Models: all known K*→Kπ+ resonances only all known K*→Kπ+ and Z+→ψ(2S)π+ favored by data

[cu][cd] tetraquark? neutral partner in ψ’ π0 expected D*D1(2420) molecule? should decay to D*D*π

PRL100, 142001 (2008)

PRD80, 031104 (2009)

Significance: Significance: 6.46.4σσ

MeV 107

MeV443374865343

19151312

M

MM22 ((

ψψ(2

S)

(2S

) ππ++ ))

MM22(K(Kππ++))

K*(890)K2*(1430)

Z+(4430)

MM22((ψψ(2S)(2S)ππ++) ) afterafter K* vetoK* veto

657M B657M BBB –̶̶̶̶̶̶DDDDDD –̶̶̶̶̶̶DDDDDD–̶̶̶̶̶̶DDDDDD –̶̶̶̶̶̶DDDDDD fit fit for model with K*’s onlyfor model with K*’s only

–̶̶̶̶̶̶DDDDDD –̶̶̶̶̶̶DDDDDD–̶̶̶̶̶̶DDDDDD –̶̶̶̶̶̶DDDDDD fit fit for model with K*’s and Zfor model with K*’s and Z

39

Z±(4430) in BaBar data? Fits to M(ψ(2S)π+): no significant Z(4430) signal

M(ψ(2S)π+) is statistically consistent between BaBar & Belle

Better to have one more experiment to examine it

PRD79, 112001 (2009)

((χχ22/ndf=54.7/58)/ndf=54.7/58)

M((2S)+)

7.2

1632

84476

MeV

MeVM

Z

Z

5.2

1217

34483

MeV

MeVM

Z

Z

9.1

3341

84439

MeV

MeVM

Z

Z

Belle peakBelle peakpositionposition

BaBar C.L @90% 103.1

Belle 10)3.2(

))2((

)(

5

59.61.81.6-0.9-

0

SZBf

KZBBf

40

Two Z±→ χc1π±

Dalitz-plot analysis of B0→ χc1π+K- χc1 →J/ψγ with 657M BB Dalitz plot models: known K*→Kπ only K*’s + one Z →χc1π± K*’s + two Z± states favored by

data

MM22 ((

χχ c1c1ππ

++ ))

MM22(K(K--ππ+ + ))

K2*(1430) K*(1680)

K*(892) K0*(1430) K3*(1780)

???

M(M(χχc1c1ππ++) ) for 1<Mfor 1<M22(K(K--ππ++)<1.75GeV)<1.75GeV22

–̶̶̶̶̶̶GGGGGG –̶̶̶̶̶̶GGGGGG fit for model with K*’s –̶̶̶̶̶̶GGGGGG –̶̶̶̶̶̶GGGGGG fit for double Z model –̶̶̶̶̶̶GGGGGG –̶̶̶̶̶̶GGGGGG Z1 contribution –̶̶̶̶̶̶GGGGGG –̶̶̶̶̶̶GGGGGG Z2 contribution

PRD 78, 072004 (2008)

Significance: Significance: 5.75.7

MeV177

MeV4248

MeV82

MeV144051

316546139

2

180443529

2

47212217

1

2041

1

Z

Z

Z

Z

M

M

Waiting for experiments to confirm them!

41

Search for X/Y states in Y(1S) radiative decays

42

Y(1S)γX/Y

5.8 fb-1 @ Y(1S) res.1.8 fb-1@ 9.43 GeV

●σ(e+e- ψ (2S))=20.2 ±1.1(stat.) pb● Except for the ISR produced ψ (2S), there are only a few events scattered above the ψ (2S) peak ● No events from J/ ψ sidebands. But one candidate around X(3872) mass region● B(Y(1S)γX(3872))B(X(3872)π+π-J/ψ)<2.2x10-6

prel

imin

ary

NEW!NEW!

● There are two events scattered above 3.6 GeV. One is at 3.67 GeV, the other is at 4.23 GeV. The orresponding 3π masses are at 0.54 GeV and 1.04 GeV ● B(Y(1S)γX(3872))B(X(3872)π+π- π0J/ψ)<3.4x10-6 ● B(Y(1S)γX(3915))B(X(3915) ω J/ψ)<3.4x10-6 pr

elim

inar

y

B(Y(1S)B(Y(1S)γγY(4140))B(Y(4140)Y(4140))B(Y(4140) J/ J/ψψ)<2.6x10)<2.6x10-6-6

43

NEW!NEW!Y(1S)Y(1S)γγXXCJ CJ //ηηcc

5.8 fb-1 @ Y(1S) res. 1.8 fb-1@ 9.43 GeV

5.8 fb-1 @ Y(1S) res. ●No clear XcJ or η signal is observed

● B(Y(1S)γXc0)<5.0x10-4

● B(Y(1S)γXc1)<1.5x10-5

● B(Y(1S)γXc2)<1.2x10-5

● B(Y(1S)γ ηc)<6.4x10-5

● The above upper limits do not contradict with the calculation in K.T.Chao et al.,hep-ph/0701009

For comparison, we also studied:

ηηcc KKSSKKππ , K+K- , K+K- ππ++ π π-, 2(-, 2(π π ++ππ-), 2(K-), 2(K

+K-) and 3(+K-) and 3(π π ++ππ-)-)

44

Possible BESIII contribution

• BESII fine scan 10 years ago (one of the best cited BES paper

s)• BESIII will do it (USTC/IHEP group will submit proposal)• The Y states should also appear in this plot• The X states via decays of excited s; is the Z+ iso-vector?

From PDG

45

Summary of the talkMany XYZ states were observed in B-factories and other e

xperiments in XYZ charmonium + light mesonThey could be exotic hadrons such as mole

cular state, tetraquark state, or hybridsor just charmonium states, threshold effect, FSI effect or s

ome other unknown QCD effect.

Both theorists and experimentalists should continue work hard and patiently for possibly very rare (even non-existing) exotic hadrons! (Is exotic hadron another ether?) Thanks a lot.

46

backup

47

Name JPC Γ(MeV) Decay modes Experiments interpretation

X(3872) 1++ <2.3 J/, J/, DD*, … Belle/CDF/D0/BaBar DD* molecule?

X(3940) 0?+ ~37 DD* (not DD, ωJ/ψ) Belle ηc’’(?)

Y(3940) ??+ ~30 ωJ/ψ (not DD*) Belle/BaBar

Y(4140) ??+ ~11 J/ψ Belle ccss?

X(4160) 0?+ ~140 D*D* (not DD, DD*) Belle ηc’’(?)

Y(4008) 1-- ~220 J/ Belle (not Babar)

Y(4260) 1-- ~80 J/ BaBar/CLEO/Belle ccg hybrid?

X(4350) ??+ ~13 , J/ψ Belle ccss?

Y(4360) 1-- ~75 (2S) BaBar/Belle

Y(4660) 1-- ~50 (2S), ΛcΛc (?) Belle

Z±(4430) ??? ~100 ψ(2S)π± Belle (not Babar) 4-quark?

Z±(4050) ??? ~80 χc1π± Belle 4-quark?

Z±(4250) ??? ~180 χc1π± Belle 4-quark?

XYZ states

charged Zcharged Z

neutral X and Yneutral X and Y

48

Shows up in all data subsamples

Z(4430)

49

Belle-BABAR comparison (Z(4430))Uncorrected data in the K* veto regionBABAR preliminary

Both Belle and BABAR data are re-binned (to calculate χ2) and side-band subtractedThe BABAR data are normalized (*1.18) to the Belle sample; Luminosity ratio is 1.46 The data distributions are statistically consistent (χ2=54.7/58)

From J. Brodzicka, LP09

50

BaBar doesn’t see a significant Z(4430)+

“For the fit … equivalent to the Belle analysis…we obtain mass

& width values that are consistent with theirs,… but only ~1.9from zero; fixing mass and width increases this to only ~3.1.”

Belle PRL: (4.1±1.0±1.4)x10-5

51

Compare with PRL results (Z(4430))

Signif: 6.4Published results

Mass & significance similar,width & errors are larger

With Z(4430)

WithoutZ(4430)

Belle: = (3.2+1.8+9.6 )x10-5 0.9-1.6

BaBar:

No big contradiction

K* veto applied

52

Charmonia

2 M(D)

recently measured

Quantum numbersQuantum numbers

(4160)

(4415)

(4040)

(3770)χc2′

′

ηc′

ηc

J/

χc2

χc0

hcχc1

n(2S+1)LJ

n radial quantum numbern radial quantum numberS total spin of S total spin of qqqqL relative orbital mom.L relative orbital mom. L = L = 0, 1, 2 0, 1, 2 → → S, P, DS, P, DJ = S + LJ = S + LP = (–̶̶̶̶̶̶1)P = (–̶̶̶̶̶̶1)L+1L+1 parity parityC = (–̶̶̶̶̶̶1)C = (–̶̶̶̶̶̶1)L+SL+S charge conj. charge conj.

c c

Many empty slots to fill Expected broad states decaying to DD, DD*, D*D*

All states observedGood agreement with QCD predictions

53

Energy scans by BESII in ‘98-99

Refit of R spectrum: with interferences between ψ 1-- states

Charmonia above DD

PLB660, 315 (2008)

Many decay channels allowed: Many decay channels allowed:

fit complicated fit complicated model dependencemodel dependence

4415416040403770

8624661301681330BESδ

21.273.315.172.714.481.26.525.4BES

2062810310802.723.0PDG2006MeVΓ

7.54415.26.04191.64.64038.51.83771.4BES

4442134153140392.43771.1PDG2006MeVM

4415416040403770

54

The Y(2175) at BaBarBabar measured e+e-→ +/0-/0 and f0(980)observed the Y(2175) f0(980).

Phys. Rev. D 76, 012008 (2007)

M = 2175±10 ±15 MeV = 58±16 ±20 MeV

Y(2175) f0(980)

L=232 fb-1

J/

55

Y(2175) in J/ f0(980) at BESII

Simultaneous fit to signal and sideband events with BW+p3

BES: PRL100, 102003 (2008)

M = 2186 ± 10 ± 6 MeV = 65 ± 23 ± 17 MeV

B(J/Yf0(980)

)

=(3.23 ± 0.75 ± 0.73)x10-4

~5

56

M(Y(2175))= 2079 13 MeV

(Y(2175))= 192 23 MeV

The Y(2175) at Belle

f0(980)

+79-28

+25-61

M( (1680))= 1689 7 10 MeV

(1680))= 211 14 19 MeV

Two incoherent BWs fit as central values, f0(980) fit as one source of error

• Agree with Babar’s and BES’s measurements• Width larger than previous measurements Y(2175) = excited remains a possibilityBelle: PRD80, 031101(RC) (2009)

57

Combined BaBar+Belle data

1.8

Two incoherent BWs: 2/ndf=170/111 (C.L.=0.03%!)

M((1680)) = 1685 5 MeV ((1680)) = 208 11 MeV M(Y(2175)) = 2080 12 MeV (Y(2175)) = 182 20 MeV

58

Combined BaBar+Belle data

2.8

Two coherent BWs: 2/ndf=158/110 (C.L.=0.19%)

M((1680)) = 1677 6 MeV ((1680)) = 233 16 MeV M(Y(2175)) = 2112 16 MeV (Y(2175)) = 196 27 MeV

59

Combined BaBar+Belle dataf0(980)

2.7

60

Y(5S) and Y(6S) Energy scans above Y(4S): Belle: 7.9/fb Babar: 3.9/fb (0.13/fb from CESR)

Motvation: new spectroscopy like in cc? Babar inclusive: fit to hadronic x-section Belle exclusive: study of di-pion transitions

Large dipion widths. For other bb: O(keV)

Pure bb state or Yb→Y(nS)ππ contributes?

PRL100, 112001(2008)

arXiv:0809.4120

fit: coherent Y(5S) +Y(6S) fit: coherent Y(5S) +Y(6S) +continuum+continuum

Y(n

S)

Y(n

S) π

ππ

π x

-se

ctio

n [p

b] x

-se

ctio

n [p

b]

arXiv:0810.3829

Inclusive and exclusive Inclusive and exclusive dipion x-sections inconsistent dipion x-sections inconsistent with PDG Y(5,6S) parameterswith PDG Y(5,6S) parameters

61

CLEOPRL 54, 381 (1985)

(5S)

Analogy ~ open threshold

CLEO: PRL 54, 381 (1985)

CUSB: PRL 54, 377 (1985)

Y(2175)

Y(4260)

Y(10890)

62

CLEOPRL 54, 381 (1985)

(5S)

CLEO: PRL 54, 381 (1985)

CUSB: PRL 54, 377 (1985)

We are exploring a mass region with many open-flavor threshold!

Constructive interference between amplitudes? Need more study!

BES: PRL 88, 101802 (2002)

What are (5S), (4260), (??)?

63

Is X(3872) a molecule?

• Simulation by models

• Production rate in CDF