1、Cosmological constantEinstein (1917)Universebaryons52768“Higgs” condensateEnglert-Brout, Higgs (1964)barequark3quark“Chiral” condensateNambu (1960)quark3 hadronQCD Spectral Functions and DileptonsT. Hatsuda (RIKEN)Condensates Elementary excitationsOutlineI.QCD symmetries II. Chiral order parametersI
2、II. In-medium hadronsIV. Summary“The Phase Diagram of Dense QCD”K. Fukushima + T.H., Rep. Prog. Phys. 74 (2011) 014001“Hadron Properties in the Nuclear Medium”R. Hayano + T.H., Rev. Mod. Phys. 82 (2010) 2949“QCD Constraints on Vector Mesons at finite T and Density” T.H., http:/www-rnc.lbl.gov/DLS/DL
3、S_WWW_Files/DLSWorkshop/dilepton.html (1997) Make an estimate before every calculation, try a simple physical argument (symmetry! invariance! conservation!) before every derivation, guess the answer to every paradox and puzzle. John Wheelers First Moral Principle from “Spacetime Physics (Taylor Whee
4、ler, 2nd ed.)”Symmetry realization in QCD vacuum Symmetry realization in CD vacuum Chiral basis :QCD Lagrangian : classical QCD symmetry (m=0) qqmqAtiqGGL aaaa g )(41 Quantum QCD vacuum (m=0) Chiral condensate : spontaneous mass generationAxial anomaly : quantum violation of U(1)A Dim.3 chiral conde
5、nsate in QCD Di .3 chiral condensate in CD Banks-Casher relation (1980)00Di Vecchia-Veneziano formula (1980)Gell-Mann-Oakes-Renner (GOR) formula (1968)Examples Axial rotation : Axial Charge : Order parameters : NOT unique ! II. Chiral order parametersOrder parameter : = 0 (no SSB) 0 (SSB) （）Spectral
6、 evidence of SSB in QCDSpectral evidence of SSB in QCDT.H. LBNL WS (1997) ALEPH Collaboration, Phys. Rep. 421 (2005) 191 - from-decays at LEP-1 - from -decays at LEP-1 V(s)/s A(s)/s V(s)- A(s)/sEnergy weighted “chiral” sum rules from QCD (mq=0)Dim.6 chiral condensateKoike, Lee + T.H., Nucl.Phys. B39
7、4 (1993) 221Kapusta and Shuryak, PRD 49 (1994) 4694Klingl, Kaiser and Weise, NPA 624 (1997) 527 -pQCD()-pQCD()= C4 -pQCD()= C6 +C6Dim.4 gluon condensateDim.6 quark and gluon condensatesDilepton data(after Cocktail subtraction) Space-time average (by hydro or other models)Lattice QCD simulations (with gradient flow method)+Energy weighted “vector” sum rules from QCD (mq=0)III. In-medium hadrons
