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. Ortega Nuclear Physics Group and IUFFyM University of Salamanca

The group of the Universtity of Salamanca Heavy hadron spectroscopy Fernandez, Entem, Segovia, Ortega B Weak Decays Feanandez, Entem, Hernandez, Segovia Effective-field theories Entem, 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 scenario The constituent quark model The coupled channels formalism The meson-meson sector The baryon meson sector Summary

Charmonium before B-factories

1980 – 2002 : no new charmonium states 5

SLAC Data taking : 2000 – 2010 e + e – →  (4S) E cms ~ 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) Z b (10610), Z b (10650) Z c (3900), Z c (4025) Z b (10610), Z b (10650) Z c (3900), Z c (4025) 8

Some examples

Quantum numbers compatibles with J PC =1 ++ and J PC =2 -+ (ruled out by the recent LHCb data ) Width: Γ< 2,3 MeV Mass: → below D 0 D *0 mass threshold X(3872)

X(3872) gamma decay

The XYZ near 3940 MeV Babar M=3914 ±4.1 J PC =? J PC =1 ++ J PC =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/c 2 Γ = 23 ± – 8 MeV γ e–e– e+e+ J/  e+e+ e–e– γ ω X J = 0, 2 only 2σ difference with Z(3930) mass good agreement with BaBar’s Y(3940) mass seen in ωJ/ψ for J P = 0 +   × B(X(3915)  ωJ/ψ) = (69 ± –18 ) eV ωJ/ψ partial width ~ 1 MeV Quite large for conventional charmonium X(3915)

Γ c c  e+e+ e–e– e+e+ 1 – – s=E 2 cm -2E  E cm D D -G(3900) J PC =1 - -

_  (5S)  (1S)  +  -  (5S)  (2S)  +  -  (5S)  (3S)  +  -  (5S)  h b (1P)  +  -  (5S)  h b (2P)  +  - phsp note different scales phsp no non-res. contribution M[ h b (1P) π  ]M[ h b (2P) π  ] Two peaks are observed in all modes! Belle: PRL108, (2012) Z b (10610) and Z b (10650)

 (3S) h b (2P) h b (1P)  (2S)  (1S)  b (2S)  b (1S)  (4S)  (10860)  (11020) Mass, GeV/c 2 2M(B) partial  (keV) –– ++ ZbZb + J PC = Z b (10610) and Z b (10650) should be multiquark states Z b (10610) and Z b (10650)

B*B*π BB*π PhSp Z b (10650) alone Z b (10650)+ PhSp Z b (10610) + Z b (10650) Z b (10610)+ PhSp Z b (10610) + Z b (10650) + PhSp 88 Z b (10610) Z b (10650) 6.8  BB*π data fits (almost) equally well to a sum of Z b (10610) and Z b (10650) or to a sum of Z b (10610) and non-resonant. B*B*π signal is well fit to just Z b (10650) signal alone

B(*)B* channels dominate Z b decays ! with Z b 0 w/o Z b 0 with Z b 0 w/o Z b 0 arXiv: Z b (10610) and Z b (10650)

Z c (3900) BESIII, PRL110,252001(2013) Belle, PRL110,252002(2013) hep-ex/ CLEO-c Charged object. Cannot be conventional charmonium

Λ C (2940) + 20

X(3250) PRD (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

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. C (2000) –B. Juliá-Diaz, J. Haidenbauer, A. Valcarce, and F. Fernández. Physical Review C 65, , (2002) Baryon spectrum –H. Garcilazo, A. Valcarce, F. Fernández. Phys. Rev. C 64, , (2001) –H. Garcilazo, A. Valcarce, F. Fernández. Phys. Rev. C 63, (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 (2008).Reports –A. Valcarce, H. Garcilazo, F. Fernandez, P.Gonzalez Rep. Prog. Phys (2005) –J. Segovia, D. R. Entem, F. Fernandez, Int. Jour. Mod. Phys. E (to be published) The constituent quark model

Results for the sector PRD (2008)

Other XYZ states No candidates for : X(3872), X(3915) G(3900) Y(3940) Y(4260)

Beyond the constituent quark model 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 mechanism should be pion exchange Two quark states can mix with two meson with the same quantum numbers

Coupling: Pair Creation Model

Coupled channels:

Hidden Charm Meson Sector

Results: J PC =1 ++ sector

J. Phys. G (2013)

Theory Results: J PC =1 ++ sector J. Phys. G (2013)

Results: J PC =0 ++ sector J. Phys. G (2013)

Results: J PC =1 -- sector

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

JPJP isospinstateM (MeV)/c 2 E b (MeV) (MeV) 3/2-0D*N2940, /2-2D*Δ3232, /2-1D*Δ3226, Some selected states 47

JPJP IsospinstateM (MeV)/c 2 E b (MeV)(MeV) 3/2 - 0D*N2940, /2 - 2D*Δ3232, /2 - 1D*Δ3226, StateM (MeV)/c 2 (MeV) Λ c (2940) + X(3250) Λ c (2940) + → D*N (I) J P = (0) 3/2 - X(3250) → D* Δ (I) J P = (1) 5/2 - or (I) J P = (2) 3/ Some selected states

Λ b partner of Λ c (2940) + Λ b (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 J P =3/2 - which can be identify with the Λ c (2940) + state The recently reported X c (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) Observed by Belle Collab. produced in Helicity angle distribution favours J=2 Our results M=3968 MeV.  =49.1 MeV.

M=(4156  15)MeV/c 2  =(139  21)MeV +25 − −  X(4160) D * reconstructed D * tag Results for XYZ states: X(4160) M=4166 MeV/c 2  =122.9 MeV Our results (  (D*D*) =52.3 MeV) e + e −  J/  D * D * observed by Belle in

Coupling formalism with T matrix

Coupling elements

Results for XYZ states