hot quark soup 30 years

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1、30YearsofHotQuarkSoupWhathavewelearnedabouthightemperatureQCD?LaurenceYaffeyaffe@phys.washington.eduUniversityofWashingtonUWColloquium,March7,2005–p.1/23AsymptoticFreedomGross,Politzer,Wilczek,1973Self-interactingspin-1gluons)anti-screeningofcolorchargebyvacuumfluctu

2、ations(unlikeQED)Rquarkds(R)(s)<0dlnR.2Qs(Q)ln9QCDfrom:S.Bethke,hep-ex/0407021UWColloquium,March7,2005–p.2/23ExtremeQCDHightemperatureand/orhighbaryondensityisrelevantfor:earlyuniversecosmologyneutronstarcoresheavyioncollisionsandistheoreticallyinteresting!C

3、ollins&Perry,1975:Superdensematter:NeutronsorAsymptoticallyFreeQuarks?Thequarkmodelimpliesthatsuperdensematter(foundinneutron-starcores,explodingblackholes,andtheearlybig-banguniverse)consistsofquarksratherthanofhadrons.Bjorkenscalingimpliesthatthequarksinteractweak

4、ly.Anasymptoticallyfreegaugetheoryallowsrealisticcalculationstakingfullaccountofstronginteractions.Equallytrueathightemperature.UWColloquium,March7,2005–p.3/23Equilibriumthermodynamics:qualitativelowtemperature:“confinedphase”gasofhadrons(baryons&mesons)QCDhightemper

5、ature:“deconfinedphase”soupofquarksandgluonsQuarklessQCD:Sharpdistinctionbetweenconfined(glueballs)anddeconfined(unboundgluons).Confinement/deconfinementphasetransition:=condensationofelectricfluxtubes(L.Susskind,1979)=spontaneousZ(3)symmetrybreaking(N.Weiss,1981)=first

6、ordertransition(B.Svetitsky,L.Yaffe,1982)UWColloquium,March7,2005–p.4/23PhasediagramwithquarksspontaneouslybrokenZ(3)symmetryN=2fPureGauge¥1storder2ndorder1stconf./deconf.O(4)?2ndorderZ(2)tricmsN=3fquarkmass?phys.crossoverN=1fpointm?s2ndorder1storde

7、rZ(2)chiralsym.1st000m,m¥temperatureudspontaneouslybrokenchiralsymmetryfrom:P.Petreczky,hep-lat/0409139threeflavors,equalmassthreeflavors,unequalmassUWColloquium,March7,2005–p.5/23Equilibriumthermodynamics:analyticEquationofstateatasymptoticallyhightemperature(p=press

8、ure,(T)g(T)2=4,noquarks):sp2=8(Stefan-Boltzmann8gluons)T44521g(T)(Shuryak,Chin,1977)632+g(T)(Debyescreening,Kapusta,1979)343+g(T)