cc spectroscopy at elle

S.L.Olsen Hawaii

QWG 2004 WorksopIHEP Beijing

_

B-factory bonuses:

new insights/puzzles about charmonium

c’ X(3872)

M(KsK)

BK Ks BK +-J/

M(+-J/

ccc0

J/recoil mass

e+e-J/cc

??‘

BK J/

M(J/

??

bccs is a dominant process

b

c

c

s

Vcb

cosC

J/, ’, c, c1,…

Brs~10-2

(inclusive)

CKMfavored

W-

B mesons are a good source for charmonium and other cc states

>900pb-1/day(~1M BBs/day)

1.2x1034/cm2/s

KEKB is a good source of Bs

Kinematic variables for the (4S)

CM energy difference:

Beam-constrained mass:

22 )()2( 'c

ppEm KCMbc

BK c

BKc

2/' cmK EEEEc

B

Bϒ(4S)

Ecm/2

e e

Ecm/2

KSK

KSK

Mbc

E

1st Observation of the c‘

BK (KSK±Ŧ)Mbc for 40 MeV M(KSK) slices

3000 MeV

3640 MeV

BK c

BK c’42fb-1

KSK

KSK

Fit each binNevt = 45.3 ± 12.6 Mc’ = 3653 ± 10 MeV

c’ = 33 ± 22 MeV

Nevt = 90.5 ± 14.9 Mc = 2978 ± 5MeV

c = 33 ± 16 MeVM(KSK)

Mbc E

c:

c’:3.55 GeV

3.60 GeV

3.65 GeV

3.70 GeV

3.75 GeV

…

…

S.K. Choi et al PRL 91, 102001

Subsequent measurements

confirm higher mass value

KSK

KSK

eeJ/X

Mx

BaBar(preliminary)

3630 MeV

3642 MeV

3633 MeV

CLEOhep-ex/0306060

elle

c c‘

c’: current status

Mavg =3637±4 MeV(Crystal Ball excluded)

M(1S) = MJ/ – Mc =117±1 MeV

M(2S) = 49 ± 4 MeV

gets smaller

The X(3872) with 253 fb-1

B±K±+-J/

Nev = 48.6 ± 7.8M = 3872.4 ± 0.7 MeV

Now M( is really -like

X(3872) MassD+D*- threshold

Look at BK J/

M()

M(J

/

)

BK J/

XJ/ BK X(3872);

1: look at BK J/Dalitz Plot

M

Mbc

EM

2(J

/

)

M2(K)

BK* J/K

cut here

Slice into 40 MeV-wide M(J/) bins

Large deviationfrom phase-space

Fit

Slice into 40 MeV-wide M(J/) bins

Adding a BWhelps

FitM≈3940 ± 11 MeV≈ 92 ± 24 MeV

M(K) for the signal region

M(K) (GeV)

3880 <M(J/)<3900 MeV

No peakingIn M(K)

Look back at the masses

76’s28’s

Very clear signal

20’s26’s

What is it?• Charmonium?

– Conventional wisdom: J/ should not be a discovery mode for a cc state with mass above DD & DD* threshold!

• Some kind of -J/ threshold interaction?– the J/ is not surrounded by brown muck; can it act like an ordinary hadron?

• cc-gluon hybrid?– Predicted by lattice QCD, including states with large

hadron+cc widths, but predicted masses are ~ 4.4 GeV

J/

Next: B±K± X(3872) J/

M()

M(J

/

)

BK X(3872)

J/

look along here

M(3 J/) = MX(3872) ± 16.5 MeV(±3)

Look at 25 MeV-wide M() mass bins

EMbc

B-meson yields vs M()

12.4 ± 4.2 evts

“Sidebands”BKJ/

Non-resonantor “peaking bkgd

sidebands

Overlapregion

Cross-talk from BKJ/enhancement?

f dm = 0.75 ±0.14 evts

Check : signal yield for M(3 J/)= M X(3872) +1–3(no overlap with band) 12.4 evts 11.5 evts (expect 11.0 for no X-talk)

Other sidebands(no significant signals)

4.3 ±6.2 evts

6.4 ± 5.6 evts

Area of I and III each= 4x Area o signal bin

Non-res bkd in signal bin = 1.3 ± 1.0 evts

Branching fraction

Br(X J/)Br(XJ/)

Nev( J/) (2J/)Nev(J/)(3J/)

=

0.188

0.036

13.1 ± 4.2

62.6 ± 8.3

= 1.1 ± 0.4 (stat) ± 0.3 (syst)

Accept:ance: 10%Xtalk/Bkgnd: -20%X J/: +25%M(3)<750 MeV

significance ≈ 4

Consistent with sub-threshold X(3872) J/

• M + MJ/ = 3879 MeV (7 MeV above 3872)

– X J/ occur via virtual ’s, 3 masses cluster at the kinematic limit.

• (XJ/)/(X J/) = 1.1 ±0.4± 0.3

• In agreement with Swanson’s DD* bound-state model for the X(3872) [PLB 588,189 (2004)]

• Smoking gun for qqqq interpretation of X(3872)?- -

update continuum e+e-J/ (cc) with 287 fb-1

L=101 fb-1

2002L=155 fb-

1

2003

287 fb -1

c c0

‘c

4th peak!!non-zero continuumbelow DD threshold

• J/ J/ negligible

• confirm c’

• e+e-J/ (cc) > e+e-J/ glue

• (e+e-J/ c) > 10x theory

• evidence for c’ 2004

-

What is the 4th peak?the reconstruction and selection procedure is the same as before

Extend the fit regionno signal of X(3872)significant (>4) peak at M=3940 11 MeVN=14833 (4.5)the width is consistent w/ resolution (= 32 MeV)

X(3872)

c

c

c0

c‘

‘

What is it? c0? c ??‘ “

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

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

•Determine recoil mass

Look at M(DD(*))

DD*

DD

3940 MeV

9.9 ± 3.3 evts(4.5 )

4.1 ± 2.2 evts(2.1 )

c0 DD*‘

c DD“

What is this one?

• Too narrow to be the same as the J/ peak at 3940 MeV

• c0 or c most likely charmonium states

– DD* signal rules against c0

– Mass is a little low for c

• M(3S) would be ≈ 100MeV• can M(3S) > M(2S)

‘ “

“‘

Summary• c’ established M(2S)<M(1S)

• (X(3872)J/ = (X(3872) J/)– Good for molecules; bad for charmonium

• Broad near-threshold J/ peak– too broad for charmonium– Too light for cc-glue hybrid?– theshold interaction involving a J/ ?

• 4th peak seen in e+e- J/X– Evidence for it in DD* (rules out c0’)– If it is the c”, M(3S) > M(2S)

B-factory data

3 D 2??

h c??e+e-J/ “X”(3940)

“Y”(3940)J/

X(3872)+-0J/

M(K3) for signal bin

Events at M(3)=775 MeVKinematic limit would peak

here