XYZ mesons XYZ News from Belle

Stephen L. Olsen, Univ of Hawai’iQWG 2006 June 26-30, Brookhaven

B-factories are Charmonium factories

cc production mechanisms @ a B factory:

• B meson decays

• e+e- annihilation

• collisions

• e+e- radiative return (isr)

cc production in B decays

j=½

j=½

J = 0 or 1

Spectator model says Jcc= 0 or 1 shoulddominate exclusive BK(cc) decays.

Allowed decays all have Bf~10-3 from PDG2004

cK 0.9 x10-3

JK 1.0 x10-3

J/K* 1.4 x10-3

’K 0.7 x10-3

’K* 0.9 x10-3

c0K 0.6 x10-3

c1K 0.7 x10-3

J/K12701.8 x10-3

BK cc(J=2) still not seen

e+e- J/ + (cc)J/

X

X (almost) alwayscontains (cc)

C(X) = +1consistent with bkg

c

c0

c’

M(X)

DD

JPC = 0++, 2++

JPC = 1--cc

e+e- (cc)

XYZ particles in Belle• X(3872)

– J/ in BKJ/

• Z(3930)– DD in DD

• Y(3940)– J/ in BK J/

• X(3940)– e+e- J/X & e+e- J/ DD*

• Y(4260)– J/ in e+e- J/ NEW

Z(3931) DD at Belle

41 11 evts (5.5)

M=3931 4 2 MeV

208 3 MeV

sin4 (J=2)

Matches well to c2’ expectationsM(DD) GeV

Belle PRL 96, 082003 (2006)

Z(3930): candidate for the c2’

3931M= 3931 MeV is

~45 MeV low

=20MeV too narrow?

Masses fromBarnes, Godfrey & Swanson

PRD 72, 054026 (2005)

e+e- J/ X(3940)

e+e-J/ + X

hep-ex 0507019 submitted to PRL

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

B(D*DD)>45%

B(DD)<41%

From X(3940) → D*D:M = (3943 ± 6 ± 6) MeV< 52 MeV at 90%CL

Is the X(3940) the c”?

3940M= 3943 MeV is ~150 MeV low

<52MeV too narrow?

X(3872) in BKJ/

M(J)

’J/

X(3872)J/

PRL 91, 262001

Also seen in pp

X(3872)

CDF

hep-ex/0406022

11.6

Production properties similar to those of the ’

X(3872)D0

PRL 93, 072004 (2004)

PRL 93, 162002 (2004)

C=+1 is establishedX(3872)J/ seen in:

&Belle

PRL 96 102002

M( looks like a

X(3872)””J/ seen

CDF Belle

Belle

hep-ex/0505037

l

|cosl|

2/dof = 34/9

|cos|

|cos|

2/dof=34/9

0++ 0-+

rule out 0++ & 0 -+

J kxJ

Ruled out by Belle

Angular analysis from CDF

Ilya Kravchenko: FPCP06

1++

or2-+

Belle: Threshold peak in BKD0D00

M=3875.4 0.7 0.8 MeV

Br(BKX)Bf(XD0D00 )

= (1.27 0.31 )x10-4

Br(XD0D00)Br(XJ/)

~ 10

+0.7-1.7

+0.22-0.39

M(D

D)

E

Belle hep-ex/0606055 today!

Comments on the D0D00 mass peak

Fitted M: 3875.4 0.7 0.8 MeV+0.7-1.7

M–(mD0+ mD*0) = +4.3 0.7 MeV+0.7-1.7

PDG05

2xPDG error on mD0

(could be 2.0 MeV)

PDG MX3872: 3871.2 0.5 MeV

Here error onmD0 drops out

Nominally ~2.3above D0D*0 threshold(but errors are non-Gaussian)

~2 discrepancy

DD* “Binding Energy?”:

X(3872) has no satisfactory cc assignment

3872

rJ/ too small& r(J/) too big

c1’

• cJ/ ispin forbidden• D0D00 @ thresh. suppressed• BKcc(J=2) suppressed

c2

Y(3940) in BK J/

M≈3940 ± 11 MeV≈ 92 ± 24 MeV

PRL94, 182002 (2005)

M(J/) MeV

(Y3940 J/ > 7 MeV (an SUF(3) violating decay)

~

this is 103 x (’ J/ (another SUF(3) violating decay)

if the Z(3930) is the c2’the Y(3940) mass is toohigh for it to be the c1’

Is there a cc slot for Y(3940) ?

Can M(c1’)>M(c2’)?c1’

Mass is lowc”

“ “ “ “c0

’

39403931

e+e- isr Y(4260) at BaBar

233 fb-1

ee+J/pb

(Y4260 J/) > 1.6MeV @ 90% CL

Y(4260)

X.H. Mo et al, hep-ex/0603024

4260

4260

BaBar PRL95, 142001 (2005)Not seen in e+e- hadrons

BES data

Y(4260) at CLEO-III

Consistent results

13.3 fb-1

ISR(1S)-(4S)

13.3 fb-1

70 +40 588 23 +6Width (MeV)

4283+17 44259 8 +2Mass (MeV)

14.1 +5.2 (4.9)125 23 (~8)N

CLEO IIIBaBar

-6-6 -16-16

-4-4

-4.2-4.2

-25-25

R.Poling @ Charm 2006

Y(4260) at Belle

MX

Select e+e- ℓ+ℓ- +X; Nchg=4

Mℓ+ℓ-=MJ/30MeV; pJ/y>2 GeV; M>0.4GeV

| data4.2<MJ/<4.4

MC

M=4295 10 +11 MeV

= 133 26 +13 MeV -6

-5

Preliminary

For ’J/ in the same data:

M(’) = 3685.3 0.1 MeV(PDG: M(’)=3686.09 0.04)

BaBar vs CLEO vs Belle

BaBar CLEO III Belle (Preliminary)

N 125 23 (~8) 14.1 +5.2 (4.9) 165 24(stat) (>7)

Mass(MeV) 4259 8 +2 4283+17 4 4295 10 +11

Width 88 23 +6 70 +40 5 133 26 +13

-6

-4

-4.2

-16

-25 -6

different

“Full” report from Belle at ICHEP in Moscow

-5

No 1-- cc slot for the Y(4260)

42804280

X.H. Mo et al, hep-ex/0603024

DD** threshold in relation to the “Y(4260)”

4.28-mD

D** spectrum

M(J/) GeV

No obviousdistortions

summary• Z(3931) (DD)

– Probably the c2’

• X(3940) (e+e- J/ X)– C=+1

– Could be the c” (albeit with some stretching)

• X(3872):– JPC = 1++

– Br(X J/) large– Br(XD0D00) seen; ~ 10xBr(XJ/y)

D*D

summary cont’d

• Y(3940)– ( Y3940 J/) >7 MeVtoo

large for charmonium– Mass too low for a hybrid

• “Y(4260)”– Confirmed by Belle but at a higher mass

– (y4260J/)>1.6 MeValso very large

– JPC=1--, but not seen in e+e- hadrons- Straddles the D**D threshold, but with no

obvious distortions to the J/ line-shape

233 fb-1

conclusions

• There is a new hadron spectroscopy in the 3.5~4.5 GeV mass region

– Maybe more than one

• The new states are characterized by large partial widths (Bfs) to hadrons+J/

– Br(X(3872)J/) > 4.3% (Isospin=1)– (Y(3940)J/) > 7 MeV (SU(3) octet)– (Y(4260)J/) > 1.6 MeV

• There is no apparent transition at the D**D mass threshold

(mine, not Belle’s)

Thank You

Back-up slides

Look at e+e-J/ D(D(*))

•Reconstruct a J/ & a D•use D0K-+ & D+K-++

•Determine recoil mass

Inclusive BKx from BaBar

?

Fully reconstructed B- tags