QCD critical point search at the J-PARC energy

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QCD critical point search at the J-PARC energy

• Tomoaki Nakamura
• RIKEN

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QCD phase diagram with HIC
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QCD critical point
H. Fujii, Phys. Rev. D67, 094018 O. Scavenius
et al, Phys. Rev. C64, 045202
Y. Aoki et al., Nature 443, 675
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Theoretical predictions on the CP
M. A. Stephanov, hep-lat/0701002
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Experimental observables

• K/p ratio vs. collision energy
• K is sensitive only s quark production.
• K/p is roughly proportional to the
  strangeness/entropy.
• strangeness/entropy ratio will be independent of
  collision energy near the Tc.

NA49, Phys. Rev. C77, 024903

• Event-by-event fluctuations
• Electric charge ? Fractional charge of quark
• Quantum number (e.g. baryon) ? Hadronization
• Mean pT ? Specific heat
• Multiplicity (total) ? Compressibility
• Multiplicity (differential) ? Density correlation

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Advantages at the J-PARC

• Intermediate beam energy
• will be match for the QCD critical point search.
• Fixed target experiment
• can obtain larger luminosity as compared with
  collider.
• Large acceptance
• is necessary to measure the event-by-event
  observable, especially for the longitudinal
  direction.

J. Cleyman et al. Phys. Rev. C73, 034905