Nonstandard mesonsStephen L. Olsen University of Hawai’i

c c

ud

uud

u

u cuc

•tetra-quarks

•meson-meson molecules

•q q – q q diquark pairs

•q q-gluon hybrids

•nucleon-antinucleon baryonium

u cuc

This talk

• Candidate non-standard mesons with hidden charm from Belle & BaBar

• Candidate baryonium meson from BES

c cu cuc

ud

uud

u

probably no time for:

Concentrate on “hidden charm” systems

• standard cc mesons are:– best understood theoretically– narrow & non overlapping

• c c systems are prolifically produced in B meson decays.

b

cc

s

Vcb

cosC

CKM favored

W-

c cu cuc

(i.e containing c & c)

Thanks to KEKB, Belle has lots of B mesons

(>1M BB pairs/day)>1fb -1/day

Design: 10 34

Charmonium primer

(’J/) 70 keV

(”J/) 50 keV

(’J/) 5 keVSUF(3) violating

These stateshave all been

identified

These stateshave not yet been found Hadronic transitions

(’J/) 0.3 keVisospin violating

EM transitions(E1) 100~300 keV

(allowed M1) 1 keV

DD(*) decays dominate~wide (10’s of MeV)

Below DD(*) thresholds~narrow (~<MeV )

X(3872)J/

BK J/

M(J) –M(J/)

’J/

X(3872)J/

S.-K.Choi, S.L.Olsen et al (Belle)PRL 91 262001 (2003)

The X(3872) is well established

seen in 4 experiments

X(3872)

CDF

X(3872)

D0

hep-ex/0406022

9.4 11.6

BaBar

Is it a cc meson?

3872 MeV

If so, it must beone of these?

no obvious cc assignment

3872

c”

hc’

c1’

2

c2

3

M too low and too small

angular dist’n rules out 1

J/ way too small

c too small;M() wrong

c& DD) too small

c should dominate

SLO hep-ex/0407033

go back to square 1

DetermineJPC

quantum numbersof the X(3872)

with minimal assumptions

JPC possibilities (for J ≤ 2)

0--

exotic

violates parity

0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

1-+

exotic

DD allowed

1++

(c1’)

1+-

(hc’)

2- -

(2)

2- +

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

JPC possibilities0-- ruled out; JP=0+,1- & 2+ unlikely

0--

exotic

violates parity 0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

1-+

exotic

DD allowed

1++

(c1’)

1+-

(hc’)

2- -

(2)

2- +

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

Strong evidence for C=+1

13.6 ± 4.4 X(3872)J/evts (>4significance)

X(3872)J/

virtual (782)?

X(3872)J/

Bf(XJ/)

Bf(XJ/)=0.14 ± 0.05

Br(X3J/)Br(X2J/) = 1.0 ± 0.5

M()

M()

X(3872)J/

Fits to (760)

JPC possibilities (C=-1 ruled out)

0--

exotic

Violates parity 0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S)) 1-+

exotic

DD allowed

1++

(c1’)

1+-

(hc’)

2- -

(2) 2- +

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

Angular Correlations

K

J/

J=0J=0X3872

Jz=0

z

Rosner (PRD 70 094023)

Bugg (PRD 71 016006)

Suzuki, Pakvasa (PLB 579 67)

l

|cosl|

2/dof = 34/9

|cos|

|cos|

2/dof=34/9

2/dof=18/9

0++ 0-+

rule out 0++ & 0 -+

J kxJ

JPC possibilities (0-+ & 0++ ruled out)

0--

exotic

violates parity

0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S)) 1-+

exotic

DD allowed

1++

(c1’)

1+-

(hc’)

2- -

(2) 2- +

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

M() can distinguish -J/ S- & P-waves

S-wave: 2/dof = 43/39 P-wave: 2/dof = 71/39

q*roll-off

q*3

roll-off

(CL=0.1%)(CL= 28%)

Shape of M() distribution nearthe kinematic limit favors S-wave

Possible JPC values (J-+ ruled out)

0--

exotic

violates parity

0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

1-+

exotic

DD allowed1++

(c1’)

1+-

(hc’)

2- -

(2)

2- +

(c2) 2++

DD allowed

c2’)

2+-

exotic

DD allowed

X(3872) D0D00 ?

11.3±3.6 sig.evts (>4)

Bf(BKX)Bf(XDD)=2.2±0.7±0.4x10-4

D*0D00?

M(D0D00)

• 1++ : DD* in an S-wave q*

• 2++ : DD in a D-wave q*5

Strong threshold suppression

Possible JPC values (2++ ruled out)

0--

exotic

violates parity

0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

1-+

exotic

DD allowed1++

(c1’)

1+-

(hc’)

2- -

(2)

2- +

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

1++

can it be a 1++ cc state?

1++c1’(the only possibility)

3872

Bf(XJ/)>4%is very large for an isospin-violating

channel

(Isospin violating)

Expectations for ’c1

(’c1 J/) 11 keV Barnes Godfrey PRD 69

054008

(’c1 J/) = ? (’ J/) 0.3 keV (“educated” guess?)

Bf(XJ/)

Bf(XJ/) 30 ~ 40

Bf(XJ/)

Bf(XJ/)=0.14 ± 0.05

Expect:

Measmnt:

>200x discrepancy

c1’ component of X(3872) is few% (at most?)

can our “education” really be this

bad?

Intriguing fact

MX3872 =3872 ± 0.6 ± 0.5 MeV

mD0 + m D0* = 3871.2 ± 1.0 MeV

lowest masscharmed meson

lowest mass spin=1charmed meson

D D*

2 loosely bound qq color singlets

with M = mD + mD* -

u

cu

c

one exchangeattractive for 1++ Tornqvist PLB 590, 209 (2004)

Deuson? deuteron-like DD* bound state?

X(3872) = D0D*0 bound state?

• JPC = 1++ is favored

• M ≈ mD0 + mD0*

• Large isospin violation is natural (& was predicted):

|D0D*0> = 1/2(|10> - |00>)

• (XJ/) < (XJ/) was predicted

• (XD0D00) too large?

• Bf(B0K0X3872)/Bf(B+K+X3872) too large?

Equal mixture of I=1 & I =0

Swanson PLB 598, 197 (2004)

Tornqvist PLB 590, 209 (2004)

Swanson PLB 588, 189 (2004)

Braaten & Kusunoki PR D71, 074005 predict: <0.08BaBar measurement (hep-ex/0507090): 0.5 0.3

diquark-antidiquark?

Maiani et al predict: M = M(Xu) – M(Xd) = 8 3 MeV

BaBar (hep-ex/0507090) reports: M = 2.71.3 0.2 MeV

u cuc

d cdc

Maiani etal predicta doublet of statesPRD 71,014028 (2005)

Xu= Xd=

B+K+Xu B0K0Xd

BaBar BaBar

Are there others?Is the X(3872) a one-of-a-kind curiousity?

or the 1st entry in a new spectroscopy?

Look at other B decays hadrons+J/

BK J/

BK J/

BK J/

BK J/ in Belle

“Y(3940)”M≈3940 ± 11 MeV≈ 92 ± 24 MeV

Mbc Mbc Mbc

S.K. Choi & S.L.Olsen et al.(Belle), PRL94, 182002 (2005)

M(J/) MeV

Y(3940): What is it?

• Charmonium?– Conventional wisdom: (SU(3)-

violating) J/decayshould not be a discovery mode for a cc state with mass above DD & DD* threshold!

eg.Brambilla et al (QWG) hep-ph/0412158

• cc-gluon hybrid?– predicted by QCD,– decays to DD and DD* are suppressed (“open-charm” thresh = mD + m D** = 4.3 GeV)

– large hadron+J/ widths can occur– masses expected to be 4.3 ~ 4.4 GeV

(higher than what we see)

Horn & Mandula PRD 17 898 others

/ISR Jee

J/ sideband

Well above DD & DD* threshold but wide & found in a suppressed

mode??

M=4259 8 MeV = 88 23 MeV

B. Aubert et al. (BaBar)hep-ph/0506081

Y(4260)

10.58 GeV

4.26 GeV

not seen in (e+e-hadrons)at Ecm =4.26 GeV

J.Z. Bai et al. (BESII)PRL 88 101802

BES

BaBar’s Y(4260)

(e

+e

- h

ad

ron

s)

summary• X(3872):

– Existence well established– JPC = 1++

– Br(X J/) too high for charmonium– Br(XD0D00) too high for molecule

– Br(B0 KSX3872) also too high for molecule(?)

– M too small for diquarks?

– Mass too low for hybrid

by a factor o

f

more than 200!

still under study

The more we learn more about it the more puzzling it

becomes.

(M(Xu) (from B+K+Xu) - M(Xd) (from B0KSXd)

summary (cont’d)

• Y(3940) Belle– ( Y3940 J/too high for charmonium

– Mass too low for a hybrid

• Y(4260) BaBar– (y4260J/also way too high

– 1--, but not seen in e+e- hadrons

by factors of ~103

Mahalo

enjoy mid-autumn festival in Hawaii

•X(3872)

•Y(3940)

•Y(4260)

•…

Homeless mesons

但願人長久千里共嬋娟

Back-up slides

Baryonium at BES???

ud

uud

u

J/ pp (at BES)

M(pp)

M(pp)-2mp (GeV)

0 0.1 0.2 0.3

M=1859 MeV/c2

< 30 MeV/c2 (90% CL)

+3 +510 25

3-body phase space

acceptance weighted BW

Phys. Rev. Lett. 91, 022001 (2003)   

Baryonium potential & Wave fcn

X ’ should be a strong channel

-V0(r)

Potentialbarrier

G.J. Dung & M.L. Yan hep-ph/0502127

“Rectangularized”Skyrmion-type

potentialI = 0, Jpc=0-+

pp annihilationM ~ 1860 MeV ~ 16 MeV large

uncertainties

M(’) from J/ ’

54264obsN

410)4.04.02.2()()( XBXJB

7.7+- mass spectrum for +- & modes

BESII Preliminary

59.18.0 10)4.00.7()()(:..

ppXBXJBfc

M = 183463 MeV = 68 20 8 MeV

I=0 FSI

ppp mM 2

In good agreement

with X(1835)

M = 1830.6 6.7 MeV

= < 153 MeV @90%C.L.

Re-fit J/ p p including FSI_

Sirbirtsev et al. (PRD 71 054010 )

Appendix

• Other new hidden charm particles from Belle (near 3940!)– X(3940)– Z(3931)

Other new particles from Belle

e+e-J/ + X

X(3940)DD* seen(DD & J/ not seen)

Z(3931) DD at Belle

41 11 evts (5.5)

M=3931 4 2 MeV

208 3 MeV

sin4 (J=2)

X(3940) Y(3940) (maybe the c’’)

?

Z(3931) = c1’ (almost for sure)

• c2,c0<<c1•X(3872) production much lower than for other Charmonium states:•can set lower limit on B.F.

Can measure absolute B.F.’s of B-K-X0

e+e-B+B-

K-X0

Lower limit on BF(XJ/) > 4.3% @ 90% C.L

244 fb-1

Very clear J/ and c signals N J/=258+- 42N c =266 +-42

c2 c1 c0

J/

Jon ColemanMoriond-QCDMarch 2005

Kinematic variables

CM energy difference:

Beam-constrained mass:

2/

2 )()2( JKCMbc ppEm

BK J

BKJ2// cmJK EEEE

B

Bϒ(4S)

Ecm/2

e e

Ecm/2

Mbc

E

1++

l

1++: sin2l sin2

K

1++ looks okay!

compute angles inX(3872) restframe

|cosl|

2/dof = 11/9

|cos|

2/dof = 5/9

M(J/) look-back plot

Fit cosl with 1++ MC

|cosl|

2/dof=11.9/9

Y(3940): What is it (cont’d)?

• a molecule?– M ≈ 2mDs

– not seen in YJ/• ( contains ss)

– width too large??– no exchange for DSDS

s csc

??PRL 93, 041801

M( J/)

Y(3940): What is it (cont’d) ?

• cc-gluon hybrid?– predicted by QCD,– decays to DD and DD* are suppressed (“open-charm” thresh = mD + m D** = 4.3 GeV)

– large hadron+J/ widths can occur– masses expected to be 4.3 ~ 4.4 GeV

(higher than what we see)

c c

Horn & Mandula PRD 17 898 (1978) + (many) others