Chaejun Song(SNU

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An EFT around Fermi surface

• Chaejun Song(SNU PNU)
• with M. Harada, C. Sasaki (Nagoya), D.-P. Min
  (SNU), T.- S. Park (KIAS)

hep-ph/0410124
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Nuclear Phase Diagram
Atomic Nuclei
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Hadrons in Medium
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Heavy Baryon Chiral Effective Theory

• Very powerful for a system of a few baryons
• Systematic expansion with Q/
• Applications to nuclear matter
• -gt new scale appears!
• Purpose study dense medium in a systematic way

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Our scales

• Small scale Q excitation scale from Fermi
  surface (or pion mass)
• Large scale chiral symmetry breaking
  scale
• Intermediate scale Fermi momentum

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Expansion scales

• Q/
• /

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Free Fermion Gas
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Analogy from HDET
See D.K. Hong PLB 473, 118 (00)
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2nd transformation and projection
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Pions in Medium
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nucleon-pion interaction
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self-interactions of nucleons
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Power Counting Rule
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Vector Correlator
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Suppressed by
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Axial Vector Correlator
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Pion Decay Constants in Medium
Decomposition into 4 parts
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Matching with HBChPT at some
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Our result
HBChPT from Meissner et al., Ann. Phys. 297, 27
(02)
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Suzuki et al., PRL92, 072302(04)
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Pion Velocity in Medium
Lee et al., NPA 741, 161(04)
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Damping of Pions

• No Damping in our valid range

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We will study

• How to determine our parameters
• How to introduce and deal with cutoffs around
  Fermi surface (go to Fermi liquid!)
• How to make it more precise
• How to go to higher densities and to check
  various scenarios