H-dibaryon properties from a QCD sum rule approach with diquark effective
fields
Kyungil KimNovember 15th , 2012, Busan, `ATHIC 2012’
Based on K. Kim, D. Jido, S.H.Lee PRC 84(2011)025204 K. Kim, D. Jido, S.H.Lee in preparation.
Motivation : Diquarks
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Quark Correlations in QCD Confinement Chiral symmetry breaking Color triplet correlation between quarks
Phenomenological Evidence of Diquark Baryon spectroscopy Deep inelastic scattering Quark condensation in dense matter
lim𝑥→ 1
𝐹2𝑒𝑛
𝐹 2𝑒𝑝=
14
qqq
q q
Motivation : Diquark Structures in HadronsSHLee and S.Yasui : EPJ C (2009)
<Diquark inside baryons>
<Quark-antiquark inside mesons>
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Diquark Structures and Heavy-quark
<Tetraquark> qq
h h
<H Dibaryon>
<Pentaquark>
ud
h us
ud
su
ds
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N*, Θcs, …
<Baryon>q
hq Λ, Ξ, …
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Λ Baryons
u d
h
<Current for Λ >
Scalar diquark fieldGauge invariant Lagrangian for diquark field
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<Color-spin interaction>
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uh- and dh-interaction are cancelled by each other.
Effective Diquark FieldsGauge invariant Lagrangian for diquark field
The relation between diquark condensate and gluon condensate
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<Propagator of diquark field>
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Single gluon with momentum
Two gluons at one vertex
λ : parameter for condensate
mΦ : diquark mass
QCDSR with Di-quark fieldsOPE Result (up to dim. 6)
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Λ BaryonsDiquark Mass (GeV) Ratio(λ)
0.2 -0.50.3 -0.20.4 -0.013
0.41 0
Parameter Set ( ms=0.12GeV, mΛ =1.115GeV)
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Λ Baryons
<Lambda_c sum rule> <Lambda_b sum rule>
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Diqaurk Masses from Various Approaches
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<QCD sum rule>
<Lattice QCD> <Bethe-Salpeter equation>
ref/Jamin PLB238(1990)387The mass difference be-tween ud- and qs-diquark is ~200MeV.
ref/Hess PRD 58,111502
ref/Cahill PRD 36,2804
Ξ Baryons
<Ξ_c sum rule> <Ξ_b sum rule>
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H-dibaryon
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<Theoretical Prediction of H-dibaryon> <Lattice QCD results>
<HAL collaboration>
<H-dibaryon search in STAR at RHIC>
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H-dibaryon
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ud
su
ds
u ds
ud s
<Current choice for H-dibaryon>
<Dispersion relation>∼ Spectral Density
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OPE Result (up to Dim. 4)
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Results in SU(3)(flavor) Sym.
<Borel Curves with various threshold>
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Summary & Outlook
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The QCD sum rule approach with diquark fields gives a good result for Λs, Ξs and H-dibaryon.
We can have a diquark mass and condensate values from Lambda.
These parameters give good masses for Lambda_c and Lambda_b.
In same approach, we can obtain the properties of ‘qs’-di-quark from Ξ_c.
We obtain the mass of H-dibaryon from a QCD sum rule ap-proach with effective diquark fields.
Pentaquarks(N*,Θcs) and tetraquarks(T_cc, T_cb) are also good candidates to apply this approach. (in progress)
Nov. 15th 2012
Thank you very much!!