Molecular Charmonium. A new Spectroscopy?

II Russian-Spanish Congress Particle and Nuclear Physics at all Scales and

Cosmology

F. Fernandez D.R. Entem, P.G. OrtegaNuclear Physics Group and IUFFyM

University of Salamanca

The group of the Universtity of Salamanca

Heavy hadron spectroscopy Fernandez, Entem, Segovia, Ortega

B Weak DecaysFeanandez, Entem, Hernandez, Segovia

Effective-field theoriesEntem, Fernandez

Neutrino nucleus scattering (Hernandez)

Tetraquarks, hypernuclei Valcarce, Fernandez- Carames

II Russian-Spanish Congress Particle and Nuclear Physics at all Scales and

Cosmology

Outline

Motivation Experimental scenarioThe constituent quark modelThe coupled channels formalismThe meson-meson sectorThe baryon meson sectorSummary

Charmonium before B-factories

Charmonium before B-factories

1980 – 2002 : no new charmonium states 5

B-factories

@ KEK @ SLAC

Data taking : 2000 – 2010

e+e– → (4S)Ecms ~ 10.6 GeV

6

Charmonium after B-factories

7

N.Brambilla et al. Eur. Phys.J. C71, 1534(2011)

X(3872)

Z(4430)

Y(4260)

G(3900)

Zb(10610), Zb(10650)Zc(3900), Zc(4025)

8

Some examples

Quantum numbers compatibles with JPC=1++ and JPC=2-+ (ruled out by the recent LHCb data )

Width: Γ< 2,3 MeV

Mass: → below D0D*0 mass threshold

23871 61 0 16 0 19M , , , MeV / c

0

1

2

3872 1 0 0 4 0 33872

3872 2 2 13872

( X ( ) J / )R , , ,( X ( ) J / )

( X ( ) ( S ))R .( X ( ) J / )

X(3872)

X(3872) gamma decay

3872X( ) J / J /

3872X( ) DD* J /

3872 2X( ) DD* ( S )

The XYZ near 3940 MeV

Babar M=3914±4.1

JPC=?JPC=1++ JPC=2++

7.7 σ

M(ωJ/ψ)

fit with no BW term

BW + background

N = 55 ±14+2–14 events

γγ X(3915) ωJ/ψ

M = 3914 ±3± 2 MeV/c2 Γ = 23 ± 10+2

–8 MeV

γe–

e+

J/e+

e–

γω

X

J = 0, 2 only

• 2σ difference with Z(3930) mass• good agreement with BaBar’s Y(3940) mass seen in ωJ/ψ

for JP = 0+ × B(X(3915)ωJ/ψ) = (69 ± 16+7–18) eV

ωJ/ψ partial width ~ 1 MeV Quite large for conventional charmonium

X(3915)

Γ

cc

e+

e–e+

1– –s=E2

cm-2EEcm

DD-

G(3900) JPC=1- -

_

(5S) (1S)+- (5S) (2S)+- (5S) (3S)+-

(5S) hb(1P)+- (5S) hb(2P)+-

phsp

note different scales

phspno non-res.contribution

M[ hb(1P) π ] M[ hb(2P) π ]

Two peaks are observedin all modes!

Belle: PRL108, 232001 (2012)

Zb(10610) and Zb(10650)

(3S)hb(2P)

hb(1P)(2S)

(1S)

b(2S)

b(1S)

(4S)

(10860)

(11020)

9.50

9.75

10.00

10.25

10.50

10.75

11.00

Mas

s, G

eV/c

2 2M(B)

260

430

290 6

1

2

partial (keV)

–

+

Zb+

JPC = 0-+ 1-- 1-+

Z b(10610) and Z b

(10650)

should be multiquark states

Zb(10610) and Zb(10650)

Zb(10610) and Zb(10650)

B*B*πBB*π

PhSp

PhSp

Zb(10650)alone

Zb(10650)+PhSp

Zb(10610) +Zb(10650)

Zb(10610)+PhSp

Zb(10610) +Zb(10650) +PhSp

8Zb(10610) Zb(10650)

6.8

BB*π data fits (almost) equally well to a sum of Zb(10610) and Zb(10650) or to a sum of Zb(10610) and non-resonant.

B*B*π signal is well fit to just Zb(10650) signal alone

B(*)B* channels dominate Zb decays !

with Zb0 w/o Zb

0

with Zb0 w/o Zb

0

arXiv:1308.2646

Zb(10610) and Zb(10650)

Zc(3900)

BESIII, PRL110,252001(2013)

Belle, PRL110,252002(2013)

hep-ex/1304.3036 CLEO-c

Charged object. Cannot be conventional c

harmonium

ΛC(2940)+

20

X(3250)

PRD 86 091102 (2012)

Taken from Gruenberger Proc Rencontres de Moriond QCD 2012)21

Non conventional charmonium

Picture from Piilone Charm 2012

Molecular hypothesis

The Constituent Quark Model

The constituent quark model

02 2

0ln20

s

qq reduced mass

• N-N interaction– F. Fernández, A. Valcarce, U. Straub, A. Faessler. J. Phys. G19, 2013 (1993)– A. Valcarce, A. Faessler, F. Fernández. Physics Letters B345, 367 (1995)– D.R. Entem, F. Fernández, A. Valcarce. Phys. Rev. C62 034002 (2000)– B. Juliá-Diaz, J. Haidenbauer, A. Valcarce, and F. Fernández. Physical Review C 65,

034001, (2002)

• Baryon spectrum– H. Garcilazo, A. Valcarce, F. Fernández. Phys. Rev. C 64, 058201, (2001)– H. Garcilazo, A. Valcarce, F. Fernández. Phys. Rev. C 63, 035207 (2001)

• Meson spectrum.– J. Vijande, F. Fernández, A. Valcarce. J. Phys. G31, (2005)– J. Segovia, A. M. Yasser, D. R. Entem, F. Fernandez Phys. Rev D. 78 114033 (2008)

• .Reports– A. Valcarce, H. Garcilazo, F. Fernandez, P.Gonzalez Rep. Prog. Phys. 68 965 (2005)– J. Segovia, D. R. Entem, F. Fernandez, Int. Jour. Mod. Phys. E (to be published)

The constituent quark model

Results for the 1- - sector

PRD 78 114033 (2008)

Other XYZ states

No candidates for :

X(3872), X(3915) G(3900) Y(3940) Y(4260)

Beyond the constituent quark model

Do we need to go beyond the naive constituent quark model to describe charmonium spectroscopy?

One possibility: Molecular state:loosely bound state of a pair of mesons.The dominant binding mechanismshould be pion exchange

Two quark states can mix with two meson with the same quantum numbers

Coupling: Pair Creation Model

Coupled channels:

Coupled channels:

Coupled channels:

Hidden Charm Meson Sector

Results: JPC=1++ sector

Results: JPC=1++ sector

J. Phys. G 40 085107 (2013)

0

1

2

3872 1 0 0 4 0 0 5233872

3872 2 2 113872

13

( X ( ) J / )R , , ,( X ( ) J / )

( X ( ) ( S ))R .( X (

,

,) J / )

Theory

Results: JPC=1++ sector

J. Phys. G 40 085107 (2013)

Results: JPC=0++ sector

J. Phys. G 40 085107 (2013)

Results: JPC=1-- sector

23900 3943 17 12M(G( )) Mev / c

Results

B(*) B(*) Molecules

Charmed Baryon Sector

The Baryon Meson system

43

The Baryon Meson system

44

D(*) N and D(*) Δ States

45

D(*)N and D(*)Δ Decays Widths

46

JP isospin state M (MeV)/c2 Eb (MeV) (MeV)

3/2- 0 D*N 2940,06 -8.02 20.761/2- 2 D*Δ 3232,70 -6.47 110.895/2- 1 D*Δ 3226,05 -13.12 107.5

Some selected states

47

JP Isospin state M (MeV)/c2 Eb (MeV) (MeV)

3/2- 0 D*N 2940,06 -8.02 20.761/2- 2 D*Δ 3232,70 -6.47 110.895/2- 1 D*Δ 3226,05 -13.12 107.5

2939 8 1 3 1 0, , ( stat ) , ( sys ) 17 5 5 2 5 9. . ( stat ) . ( sys )

State M (MeV)/c2 (MeV)

Λc (2940)+

X(3250)

3245 20 108 6

Λc (2940)+ → D*N (I) JP = (0) 3/2-

X(3250) → D*Δ (I) JP = (1) 5/2- or (I) JP = (2) 3/2-48

Some selected states

Λb partner of Λc (2940)+

Λb(2940)+

Summary

We have study the influence of molecular structures in heavy meson and baryon phenomenology

We have used a constituent quark model to study both the meson and the molecular sectors

The model describe the X(3872) and other XYZ states as D D* resonances coupled to two quark states

We have extended our calculation to the baryon- meson sector

Without change the parameters we found a ND* bound states with JP=3/2- which can be identify with the Λc(2940)+ state

The recently reported Xc(3250) can also be explained as a D*Δ molecule

As final conclusion molecular structures may play an important role in the description of the meson and baryon espectra

End

Thanks for your attention

Back slides

Results for XYZ states: Z(3930)

PRL 96 (06) 082003

• Observed by Belle Collab.• produced in

Helicity angle distribution favours J=2

( (3930)) .18 0.05 0 ..03B Z DD keV

3929 5 2 .29.9 10 2 .

M MeVMeV

DD

Our results 2 (2 )c

M=3968 MeV. =49.1 MeV.

( (3930)) 0.15 .B Z DD keV

M=(4156 15)MeV/c2

=(139 21)MeV

+25−20

+111 −61

5.5 X(4160)

D*reconstructed D*tag

Results for XYZ states: X(4160)

M=4166 MeV/c2

=122.9 MeV

Our results

((D*D*) =52.3 MeV)

2 (2 )c

e+e− J/ D*D*observed by Belle in

Coupling formalism with T matrix

Coupling elements

Results for XYZ states