Figure'2.25'from'page'92'of' Exploring*the*Heart*of*Ma2er* - - PowerPoint PPT Presentation

Figure'2.25'from'page'92'of'Exploring*the*Heart*of*Ma2er*

Quark-Gluon Plasma

The Phases of QCD

Temperature

Hadron Gas

Early Universe

Future FAIR Experiments

LHC Experiments

Nuclear Matter Vacuum

Color Superconductor

Critical Point

RHIC Experiments

R H I C E n e r g y S c a n

Crossover

Baryon Chemical Potential

~170 MeV 0 MeV 900 MeV 0 MeV Neutron Stars 1

s t

• r

d e r p h a s e t r a n s i t i

• n

FIGURE 2.25 The phase diagram of QCD is shown as a function of baryon chemical potential (a measure of the matter to antimatter excess) and temperature. A prominent feature in this landscape is the location of the critical point, which indicates the end of the first-order phase transition line in this plane. SOURCE: DOE/NSF, Nuclear Science Advisory Committee, 2007, The Frontiers of Nuclear Science: A Long Range Plan.

QCD Phase Diagram

Quark Gluon Plasma

µ T

Big Bang Color Superconductivity Nuclear Liquid Hadron Gas RHIC Supernova Neutron Stars SPS

( ρ) From'Thomas'Schaefer,'NC'State'

More'phase'diagrams'of'QCD'.'.'.'

From'Thomas'Schaefer,'NC'State'

What is QCD? What is a Phase of QCD? What is a Phase Diagram?

Phase Diagram: Equilibrium state as a function of thermodynamic (or other: mq, Nc, Nf, B) variables. Here : Ω(T, µ, V ) = −V P(µ, T)

• Other choices of independent variables: G(P, T, N), . . .
• At T = 0 have µ = E(Nq + 1) − E(Nq).
• In real experiments control parameters are more compli-

cated (beam energy Ecm, impact parameter b (→ Nch), system size A).

Pressure'vs.'Temperature'for'3'“substances”'

Thermodynamic'PotenFals'

• Use'the'thermodynamic'potenFal'

appropriate'to'the'system:'what'is'held' fixed?''If'S,V,N'then'use'internal'energy'U.'

• At'equilibrium,'the'appropriate'

thermodynamic'potenFal'is'minimized,' which'determines'the'phase;'e.g.,'S,V,N' constant'!'U'minimized;'T,V,μ'constant' !'Ω'minimized.'

• For'the'grand'potenFal'Ω,'phase'

boundaries'have'equal'temperature'T'and' chemical'potenFal(s)'μ'for'each'phase.'

From'Thomas'Schaefer,'NC'State'

What is QCD (Quantum Chromo Dynamics)?

Elementary fields: Quarks Gluons (qα)a

f

⎧ ⎪ ⎪ ⎨ ⎪ ⎪ ⎩ color a = 1, . . . , 3 spin α = 1, 2 flavor f = u, d, s, c, b, t Aa

µ

⎧ ⎨ ⎩ color a = 1, . . . , 8 spin ±

µ

Dynamics: Generalized Maxwell (Yang-Mills) + Dirac theory L = ¯ qf(iD / − mf)qf − 1 4Ga

µνGa µν

Ga

µν = ∂µAa ν − ∂νAa µ + gf abcAb µAc ν

iD / q = γµ i∂µ + gAa

µta

q

From'Thomas'Schaefer,'NC'State'

“Seeing” Quarks and Gluons

Made on 28-Aug-1996 13:39:06 by DREVERMANN with DALI_D7. Filename: DC015768_005906_960828_1338.PS_2J_3J

DALI Run=9063 Evt=7848

ALEPH

Run=15768 Evt=5906

e− e+ q q

e− e+ q g q

Jet'Quenching'in'RelaFvisFc'Heavy[Ion'Collisions'(at'LHC)'

• LHC'usually'collides'protons'on'protons'
• Four'weeks'each'year'switches'to'Pb[Pb'
• Principal'component'of'ALICE'detector'is'a'Fme'

projecFon'chamber'(TPC).'Wikipedia:'“consists'

• f'a'gas[filled'detecFon'volume'in'an'electric'

field'with'a'posiFon[sensiFve'electron'collecFon' system.'The'original'design'(and'the'one'most' commonly'used)'is'a'cylindrical'chamber'with' mulF[wire'proporFonal'chambers'(MWPC)'as' endplates.'' ALICE'detector'

• RHIC:'Au'on'Au'at'100'GeV/A'
• LHC:'Pb'on'Pb'at'2'TeV/A!'
• Jets'lose'energy'traversing'the'

fireball'!'jet'quenching'

• Amount'of'quenching'gives'

info'about'the'QGP'

From:'hfps://www.star.bnl.gov/central/focus/highPt/'

Jet'Quenching'in'RelaFvisFc'Heavy[Ion'Collisions'(at'RHIC)'