T.Barnestbarnes@utk.eduORNL / U.Tenn.Charm2006 Beijing7 June 2006The XYZs of cc:

1. Charmonium reminder.

2. The new states:

X(3943) Y(3943) Z(3931) Y(4260) cc? cc hybrids!?

How to test these possibilities.

(My) theor. numbers are from T.Barnes, S.Godfrey and E.S.Swanson, PRD72, 054026 (2005).

For BABAR, BELLE, BES, CLEO, GSI, … :

All 40 cc states expected to 4.42 GeV, all 139 of their open-charm strong modes and partial widths, all 231 open-charm strong decay amplitudes, all 153 E1 and (some) M1 EM widths.

Charmonium (cc)A nice example of a QQ spectrum.

Expt. states are shown with the usual L classification.

Above 3.73 GeV:Open charm strong decays(DD, DD* …):broader statesexcept 1D

2 22

3.73 GeV

Below 3.73 GeV: Annihilation and EM decays.

, KK* , cc, , ll..):narrow states.

Minimal quark potential model physics:

OGE + linear scalar confinement;

Schrödinger eqn (often relativized) for wfns.

Spin-dep. forces, O(v2/c2), treated perturbatively.

Here…

Contact S*S from OGE;Implies S=0 and S=1 c.o.g. degenerate for L > 0.(Not true for vector confinement.)

S*S OGE

Z(3931), X(3943), Y(3943) C = (+)

Fitted and predicted cc spectrumCoulomb (OGE) + linear scalar conft. potential

model black = expt, red = theory.

states fitted

Y(4260) JPC = 1- -

cc and cc–H from LGT

exotic cc-H at 4.4 GeV

Small L=2 hfs.

A LGT cc-sector spectrum e.g.: X.Liao and T.Manke, hep-lat/0210030 (quenched – no decay loops)Broadly consistent with the cc potential model. No LGT cc radiative or strong decay predictions yet.

n.b. The flux-tube model of hybrids has a lightest multiplet with 8 JPCs;3 exotics and 5 nonexotics, roughly degenerate: (0,1,2) , 1,1Y(4260)?

The main theme:

Comparing expt. with theory,especially for 2P cc states, through:

1st Strong decays

2nd EM ( and transitions)

Trivial observations for 2P cc open-charm strong decays:

Thresholds

DD 3.73 GeVDD* 3.87 GeV

(Ds D

s 3.94 GeV - small)

2’ 2++ 23P

2 DD, DD*

’ 1++ 23P

1 DD*

0’ 0++ 23P

0 DD

hc’ 1 21P

1 DD* but C

Detailed 2P cc predictions…

J PC-allowed D, D* modes (M < D*D*)

Looking for both DD and DD* is a good filter!

n.b. JP = 1+ DD* final states have both S and D amps.

Open-charm strong decays: 3P0 decay model (Orsay group, 1970s)

qq pair production with vacuum quantum numbers.L

I = g

A standard for light hadron decays. It works for D/S in b1 .

The relation to QCD is obscure.

After restoring this “p3 phase space factor”, the BFs are:

D0D0 : D0D*0 : D*0D*0

One success of strong decay models

An historical SLAC puzzle explained:the weakness of (4040) DD

e.g. D*D* molecule?

famous nodal suppression of a 33S

1 (4040) cc DD

std. cc and D meson SHO wfn. length scale

partial widths [MeV](3P

0 decay model):

DD = 0.1 DD* = 32.9 D*D* = 33.4 [multiamp. mode]D

sD

s = 7.8

D*D* amplitudes(3P

0 decay model):

1P1 = 0.034

5P1 = 0.151 = 1P

1

5F1

= 0

Expt. preview, M, and modes, X(3943),X(3943), Y(3943), Y(3943), Z(3931): Z(3931):

J/

2P cc Strong Widths: 3P0 Decay Model

DDDD*D

sD

s

2P23P

2 80 [MeV]

23P1

165 [MeV]

23P0

30 [MeV]

21P1

87 [MeV]

(assuming NR ccpotential model masses)

c’

0

c

X(3943)

An interesting new charmoniumproduction mechanism!

Allows access to C=(+) cc states in ee w/o using .

No or !?

X(3943)

[ref] = P.Pakhlov et al. (Belle), hep-ex/0507019, 8 Jul 2005. n.b. Eichten: X(3943) may be the 31S0 cc

c

’’.

Strong Widths: 3P0 Decay Model

33S1

74 [MeV]

31S0

80 [MeV]

3S

DDDD*D*D*D

sD

s

X(3872)

Maybe not 2P?X(3943) = 31S

0

c” ?

(Eichten)

52(10) MeV

Is the narrow expt width a problem for X(3943) = 31S0

c” ?

Let’s recalculate with M = 3943 MeV and see …

X(3943)

Yes the total width is a problem for X(3943) = 31S0

c”.

thy

= 70 MeV vs expt15(10) MeV

2

expt.

thy.

X(3943)

Y(3943) B KY(3943), Y J/

[ref] = S.-K. Choi et al. (Belle), PRL94, 182002 (2005).

Y(3943) = 23P1 cc? (Too light for cc-H.)

Expt for Y(3943): B KY(3943), Y J/ = 87 +/- 22 MeV1++ cc J/ is unusual; cc virtual DD* e.g. -> J/ ?n.b.

IS seen in B decays

Theory for 23P1(3943):

= 135 MeV

A strong DD* mode ?The only open-charm mode?

theoryexpt.

tot

Y(3943)

Z(3931) Z(3931) DD

[ref] = S.Uehara et al. (Belle), hep-ex/0507033, 8 Jul 2005.

[ JPC .ne. 1++ ]

Z(3931) = 23P2 cc ? (suggested by Belle)

Expt for Z(3931): Z(3931) -> DD MeV * BDD

= keV

thy

expt

tot

Theory for 23P2(3931):

= 47 MeV DD*/DD = 0.35 * BDD

= 0.47 keV

( from T.Barnes, IXth Intl. Conf.

on Collisions, La Jolla, 1992.)

The crucial test of Z(3931) = 23P

2 cc :

DD* mode ?

in http://web.utk.edu/~tbarnes/website/Barnes_twophot.pdf

Z(3931)

EM transitions

(How one might make 2P cc states.)

What radiative partial widths do we expect from various initial 1 cc states to 2P cc states?

E1 Radiative Partial Widths

3S -> 2P 33S1 23P

2 14 [keV]

33S1 23P

1 39 [keV]

33S1 23P

0 54 [keV]

31S0 21P

1 105 [keV]

3S -> 1P 33S1 3P

2 0.7 [keV]

33S1 3P

1 0.5 [keV]

33S1 3P

0 0.3 [keV]

31S0 1P

1 9.1 [keV]

blue = known states red = unknown

E1 Radiative Partial Widths

2D -> 1P23D

3 3P

2 29 [keV]

23D2 3P

2 7 [keV]

3P1

26 [keV]

23D1 3P

2 1 [keV]

3P1

14 [keV]

3P0

27 [keV]

21D2 1P

1 40 [keV]

2D -> 1F

23D3 3F

4 66 [keV]

3F3

5

[keV] 3F

2 14

[keV]

23D2 3F

3 44 [keV]

3F2

6 [keV]

23D1 3F

2 51 [keV]

21D2 1F

3 54 [keV]

2D -> 2P23D

3 23P

2 239 [keV]

23D2 23P

2 52 [keV]

23P1

298 [keV]

23D1 23P

2 6 [keV]

23P1

168 [keV]

23P0

483 [keV]

21D2 21P

1 336 [keV]

cJ

c2

is very sensitive to the 23S1 3D

1 mixing angle .

With approx -15o, both the ee and strong 3770 widths = theor predictions.

This is very interesting: what drives 23S1 3D

1 mixing?

Ref: R.A.Briere et al. (CLEO),hep-ex/0605070 (May 2006).

Experiment and theory [assuming = pure 3D1 cc ].

Ref: R.A.Briere et al. (CLEO),hep-ex/0605070 (May 2006).

Ref: Y.-B.Ding, D.-H.Qin and K.-T.Chao, PRD44, 3562 (1991).

new CLEOrad widths:

172 (30) 70 (17)< 21

n.b. ratios of versus J are the most reliable theor predictions.cJ

Y(4260)

Y(4260) ee Y(4260)ISR

, Y J/

log scale

Not seen in R.Hmmm?!

[ref] = BaBar, PRL95, 142001 (2005).

CLEO: Evidence for Y(4260)in J/ and J/

Y(4260)

Ref: T.E.Coan et al. (CLEO), PRL96, 162003 (2006); hep-ex/0602034v2.

channel [pb]

J/58 +/- 4

J/ 23 +/- 1

(approx. 2:1 ratio expected for I=0)

J/ 9 +/- 1

cc spectrum, potential models (dashed: nonrel L, Godfrey-Isgur R) vs data

Possible 1 state Y(4260).Note no plausible cc assignment exists.A 1 charmonium hybrid??

cc and cc–H from LGT

exotic cc-H at 4.4 GeV

Small L=2 hfs.

A LGT cc-sector spectrum e.g.: X.Liao and T.Manke, hep-lat/0210030 (quenched – no decay loops)Broadly consistent with the cc potential model. No LGT cc radiative or strong decay predictions yet.

n.b. The flux-tube model of hybrids has a lightest multiplet with 8 JPCs;3 exotics and 5 nonexotics, roughly degenerate: (0,1,2) , 1,1Y(4260)?

Characteristics of cc-hybrids.

(folklore, mainly abstracted from models, some LGT)

States

(flux-tube model):

The lightest hybrid multiplet should be a roughly degenerate set containing3 exotic and 5 nonexotic JPC;

0, 1, 2, 0, 1, 2, 1, 1

Mass ca. 4.0 – 4.5 GeV, with LGT preferring the higher range.

The 1 should be visible in ee but with a suppressed width. (Hybrid models for different reasons predict

cc(r=0) = 0, suppressing

ee .)

Decays

(flux-tube model and f-t decay model):

Dominant open-charm decay modes are of S+P type, not S+S. (e.g. DD1 not DD or DD*).

n.b. 1(1600) ’ argues against this model.

LGT(UKQCD):

Closed-charm modes like cc-H cc + light mesons are large! (Shown for bb-H; (bb) is preferentially P-wave, and “light mesons” = scalar .)

p ’p

E.I.Ivanov et al. (E852)PRL86, 3977 (2001).

1(1600)

exotic reported in ’

’is a nice channel because nn couplingsare weak for once (e.g. the a

2(1320) noted here).

The reported exotic P-wave is dominant!

The (only) strong JPC-exotic H candidate signal.

S+S, not S+P !

Strong Widths: 3P0 Decay Model

4S 43S1

78 [MeV]

41S0

61 [MeV]

DDDD*D*D*DD

0*

DD1

DD1’

DD2*

D*D0*

DsD

s

DsD

s*

Ds*D

s*

DsD

s0*

43(15) [MeV]

A warning about hybrid = S+P modes:

Theor. decay BFs of the 43S1 cc (4415).

partial widths [MeV](3P

0 decay model):

DD = 0.4 DD* = 2.3 D*D* = 15.8 [multiamp.]

DsD

s = 1.3

DsD

s* = 2.6

Ds*D

s* = 0.7 [m]

New S+P mode calculations:

DD1 = 30.6 [m] MAIN MODE!!!

DD1’ = 1.0 [m]

DD2* = 23.1

D*D0* = 0.0

DD1 amplitudes:

(3P0 decay model):

3S1 = 0 !!! (HQET)

3D1 = + 0.093

A cc state, but the main mode (thy.) isS+P, not S+S !

n.b. PDG says the 4415decays mainly to “hadrons”. Expt BFs needed!

(As for all states aboveopen-charm thresholds.)

An “industrial application” of the (4415).

Sit “slightly upstream”, at ca. 4435 MeV, and you should have a copious source of D*

s0(2317). (Assuming it is largely cs 3P

0.)

Summary, conclusions, suggestions, re expt:

X(3943), Y(3943), Z(3931) and Y(4260) …

1. X(3943) as 31S0

c’’, cc ? DD*-only checks, may be a bit small..

Just measure J P !!! (also for Y and Z!)

2. If Y(3943) is the 23P1

1’, one expects a large DD* mode, and no DD.

3. Z(3931) DD and DD* if 2’.

…

Summary, conclusions, suggestions, re expt:

Y(4260) …

4. Y(4260) as hybrid? No new cc 1 expected near this mass: if it exists it’s already something unusual.

Theory folklore says hybrids prefer S+P modes, UKQCD says + light meson(s) may be large.

Best approach would be to search for it in all accessible open charm and closed charm modes.

ee DD, DD*, D*D*, DD0*, DD

1*; J/

any other (cc) + light meson mode.

(Close and Page, hep-ph/0507199v2, PLB628, 215 (2005) gives a detailed list of modes)

Summary, conclusions, suggestions, re expt (cont.):

X(3943), Y(3943), Z(3931) …

5. E1 radiative transitions from 1- - cc states: You can find all three 23P

J cc states using

andDD, DD*.

e.g. All three E1 rad BFs of the are ca. few * 10-4. These could show whether the X,Y,Z (3.9) are 2P cc as speculated.

The End