Spectra and decays of hybrid charmonia

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Spectra and decaysof hybrid charmonia

• Yu.S.Kalashnikova, ITEP
• in collaboration with A. Nefediev, PRD77 054025
  (2008)

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Y(4260) hybrid charmonium?
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QCD string model

• Based on Vacuum Correlator Method
• Confinement gluonic correlators responsible for
• area law asymptotic for the Wilson loop
• QCD string model corresponds to the limit of
  small
• gluonic correlation length

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Excitations of the QCD string qq -gt
minimal string
P (-1)L1 C (-1)LS
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Hybrid excitationsgluon with two minimal
strings attached
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Quantum numbers

• Magnetic (lg jg)

• Electric (lg jg?1)

Lowest magnetic
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Zero-order Hamiltonian

• quarkonium

• hybrid

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Einbein fields
?0 -gt constituent mass (calculated)
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Spin-independent corrections

• Charmonium
• Self-energy
• String correction

• Hybrid
• Self-energy (the same as for cc)
• String correction

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Spin-dependent force

• non-perturbative spin-orbit (Thomas)
• perturbative spin-orbit
• hyperfine
• spin-tensor

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Trial wavefunction

• charmonium

• hybrid

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Model parameters
Charmonium spectrum (MeV)
1S0 3S1 3P0 1P1 3P1 3P2
Exp 2980 3097 3415 3526 3511 3556
Model 2981 3104 3449 3528 3514 3552
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Zero-order hybrid mass M00 4573
MeV Constituent masses ?c1598 MeV, ?g1085 MeV
Spin-independent correction -gt -90 MeV
Gluon spin-orbit common for all states -gt -103 MeV
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Predictions for hybrids 1. Spin splittings
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Predictions for hybrids2. Mass of the vector
hybrid
LGT 4379 ? 149 MeV X.-Q.Luo and Y.Liu, PRD 74
034502 (2006)
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Predictions for hybrids3. Masses of C-even
states
LGT 4400 MeV C.Michael, hep-ph/0308293 4405
? 38 MeV Y.Liu and X.-Q.Luo PRD73 054510 (2006)
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Both these calculations and lattice place a
vector hybrid at 4400 MeV
Y(4260) is not a hybrid?
Y(4320)
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Strong decays of magnetic hybrids
D
h
D
Hybrid wavefunction
Q?-Q ? 0 for SS mesons
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Selection rule
D()D()
hmagnetic
D()DJ()
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Vector
Mth4327 MeV
Mth4285 MeV
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• Due to the coupling of vector
• hybrid to S-wave thresholds DD0
• and DD1 the state should be attracted
• to these thresholds
• If the coupling is strong enough
• an extra state can be generated
• dynamically

Y(4260) and Y(4325) ?
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J-
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Y(4260) and Y(4320) as hybrids No
visible decays into DD pairs Small ee-
width The masses are a bit too low DD1 and
DD0 thresholds can attract the state If Ys
are hybrids, C-even partners are to be found
1-(4320) couples strongly to DD0 -gt
interesting threshold effect