non-standard mesons in bes iii? stephen l. olsen, univ of hawai’i bes annual mtg shi-dou, may...

Non-standard mesons in BES III?

Stephen L. Olsen, Univ of Hawai’iBES annual mtg Shi-dou, May 30-June 2, 2005

non-standard hadronsnon-qqq baryons or non-qq mesons:

Pentaquarks:e.g. an S=+1 baryon

Glueballs:gluon-gluon color singlet states

Multi-quark mesons:

qq-gluon hybrid mesons

u cuc

c c

ud

usd

mesons with “hidden charm” are a good place to look

• standard cc mesons are:– best understood theoretically– decay properties well known– narrow & non overlapping

• concentrate on charmonium-like particles that don’t match expected properties

c cu c

uc

What about the (4.03) ?

Conventional wisdom: (4.03)= S)

Ecm(GeV/c)

DD DD

*

D*D

*

D momentum spectra @ 4.03GeV

D+ D0

Ling-jun Pan, BES data

D*D*

DD*

DDD*D*

DD*

DD

Why is ((4.03) D*D*) so huge?

DD/DD*/D*D*: 1/20/64 phase-spaceCharmonium S-wave: 1/4/7 removed D-wave: 1/1/4

Suggestions

D* D*u

c

u

c

(4.03)=D*D*molecule?

c c

a cc-gluonhybrid?

PRL 38, 317

PLB 366, 323

hadronic molecules

a new spectroscopy?

DeRujula, Georgi,Glashow, PRL 38, 317 (1977)

Many possibilitiesFor BESIII

cc-gluon hybrids

another new spectroscopy?

Hybrid states

More possibilitiesFor BESIII

1–- hybridmixes with(4.03)??

“ normal”cc mesons

cc gluonhybrids

DD

Belle has candidates for each

• DD* molecular state: X(3872)– S.-K. Choi et al PRL 91, 262001

• cc-gluon hybrid: Y(3940)– S.-K/ Choi et al, PRL 94, 182882

The X(3872)

M(J) –M(J/)

’

X(3872)

M() MeV

XJ/XJ/XJ/

M(J/)

seen in:

& XD0D

M(D0D0) MeV

Ispin isviolated

C=+

X(3872) = D0D*0 bound state?

• JPC = 1++ (favored by DD* models)

• M ≈ mD0 + mD0*

• Maximal isospin violation is natural (& was predicted): |I=1; Iz= 0> =1/2(|D+D*->+ |D0D*0>) |I=0; Iz= 0> =1/2(|D+D*-> - |D0D*0>)

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

• (XJ/) < (XJ/)

Equal mixture of I=1 & I =0

Swanson PLB 598, 197 (2004)

Tornqvist PLB 590, 209 (2004)

Swanson PLB 588, 189 (2004)

X(3872) conclusionsee hep-ex/0505037 & 0505038

•JPC = 1++

•cc content is small

•matches all(?) expectations for a D0D*0 bound state

C C

D* D*u

c

u

c

BES has a candidate too!from Ling-Jun’s (4.03) DX study

Study this

Look at DD* region

D*+D+0 D*+D+0

D*+D+

D*+D++

D*0D00

D*0D0

Fits to momentum spectra are poor

Too few daughters

D0

D+

D* Br’s fixed at PDG values2/dof = 129/78

CL:0.028%

L.J. Pan, PhD thesis

Addsome (4.03)Ũ; ŨDD

2/dof = 100/73CL: 5%

Br?=16%

MŨ~3860 MeVŨ<12 MeV

L.J. Pan, PhD thesis

ŨDD

ŨDD

DeRujula, Georgi,Glashow, PRL 38, 317 (1977)

X(3872)??Ũ(3860)

ŨDD allowe

d

BK J/

“Y(3940)”M≈3940 ± 11 MeV≈ 92 ± 24 MeV

Mbc Mbc Mbc

S.K. Choi et al, PRL 94, 182882Bf(BKY)Bf(YJ/)=7.1±1.3±3.1x10-5

cc gluon candidate from Belle: Y(3940)

Y(3940): 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?

J/

Brambilla et al (QWG) hep-ph/0412158Eichten, Lane & Quigg PRD 64, 094019Barnes, Godfrey & Swanson hep-ph/0505002

Y(3940): What is it (cont’d)?

• another 4-quark state?– 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 are predicted– masses expected to be 4.3 ~ 4.4 GeV

(higher than what we see)

c c

Horn & Mandula PRD 17 898 (1978)

Close PLB 342, 369 McNiele et al PRD 65

094505

Isgur et al PRL 54, 869 (1995)

“ open charm” threshold for hybrids is here

Ecm(GeV/c)

DD

DD

* D*D

*

Hybrid states in this mass range may decay to x

J/orcc,…)x=light hadrons

Search strategies for BESIII

• DD(*) molecular states– (4.03)() + Ũ

•Study DD & DD* masses @ (4.03) (& (4.16)??)

• light cc gluon hybrids– (4.03) + ccg hybrid

•Study J/ (c, c) + light hadons () @ (4030), (4160) (& (4415)??)

Rate estimates (DD(*) molecules)(1yr = 6fb-1)

• L.-J. Pan’s thesis:~16% of (4.03)DD

yield is via:(4.03) Ũ(3860) DD

If DD recon effic ~0.1% Expect: 103

Ũ(3860)DD/yr

including

D Br’s

Rate estimates (cc-gluon hybrids)

• (4.03) + (cc gluon hybrid)– assume:((4.03)J/)~((3.77)J/

)~100keVRecon effic J/y ~ 1%

Can search in many other channels:(4.03)() + J/ ( J/, c, …)

N((4.03)J/) ~ 103/yr x((4.03) J/)

((3.77)J/)

or, or

Summary

BESIII runs at 4.03 (& 4.16 GeV + higher?)

may be very interesting.

謝謝

Announcement

謝謝

Backup slides

Look at events where 2 D mesons are found

????

L.J. Pan, PhD thesis

Expect ~ 10 ??(3860)DD events