The properties of parton- -hadron matter hadron matter The - PowerPoint PPT Presentation

The properties of parton- -hadron matter hadron matter The properties of parton from heavy- -ion collisions ion collisions from heavy Elena lena Bratkovskaya Bratkovskaya E Institut fü ür Theoretische Physik r Theoretische Physik & FIAS, Uni. Frankfurt & FIAS, Uni. Frankfurt Institut f BLTP, 7 August, 2013 7 August, 2013 BLTP, 1 1

From Big Bang to Formation of the Universe T~160 MeV � time 10 -3 sec 3 min 300000 years 15 Mrd years quarks nucleons atoms our Universe gluons deuterons α− α α α − particles − − photons Can we go back in time ? 2 2

Heavy- -ion accelerators ion accelerators Heavy � Relativistic � Relativistic- -Heavy Heavy- -Ion Ion- -Collider Collider – – RHIC RHIC - - STAR detector at RHIC STAR detector at RHIC (Brookhaven): Au+Au at 21.3 A TeV Au+Au at 21.3 A TeV (Brookhaven): 1 event: Au+Au, 21.3 TeV L=3.8 km L=3.8 km � Large � Large Hadron Collider Hadron Collider - - LHC LHC - - (CERN): (CERN): Pb+Pb at 574 A TeV Pb+Pb at 574 A TeV � Future facilities: � Future facilities: L=27 km L=27 km FAIR (GSI), NICA (Dubna) FAIR (GSI), NICA (Dubna) NICA NICA SPS SPS 3 3

The QGP in Lattice QCD The QGP in Lattice QCD Lattice QCD: Lattice QCD: Quantum uantum C Chromo hromo D Dynamics : ynamics : Q energy density versus temperature energy density versus temperature predicts strong increase of predicts strong increase of 14 energy density ε ε ε ε at a critical ε ε the energy density ε ε at a critical the 12 temperature T T C ~160 MeV temperature C ~160 MeV 10 ⇒ Possible ⇒ hadrons Possible phase transition phase transition from from hadrons QGP QGP 8 4 ε /T hadronic to partonic matter partonic matter hadronic to ε ε ε Lattice QCD: 6 (quarks, gluons) at critical energy (quarks, gluons) at critical energy µ µ µ µ B =0 4 density ε ε C ε ε ε 3 ε ε ε ~0.5 GeV/fm 3 µ µ µ µ B =530 MeV density C ~0.5 GeV/fm 2 T c = 160 MeV T c = 160 MeV 0 0.5 1.0 1.5 2.0 2.5 3.0 T/T c ���������������������������������� 3 , T - ε ε ε ε ε C Critical conditions - ε ε ε ~0.5 GeV/fm 3 , T C ~160 MeV - - can be reached can be reached Critical conditions C ~0.5 GeV/fm C ~160 MeV in heavy heavy- -ion experiments ion experiments at bombarding energies at bombarding energies > 5 GeV/A > 5 GeV/A in 4 4

The holy grail of heavy- -ion physics: ion physics: The holy grail of heavy • Search for the • Search for the critical point critical point The phase diagram of QCD The phase diagram of QCD • Study of the • Study of the phase phase transition from from transition hadronic to partonic hadronic to partonic matter – – matter Quark- -Gluon Gluon- -Plasma Plasma Quark • Study of the • Study of the in in- -medium medium properties of hadrons at high baryon density properties of hadrons at high baryon density and temperature and temperature 5 5

‚Little Bangs‘ in the Laboratory ������������� ������������� PHSD PHSD time ����� ������������������ � ������� ������� �������� ����������������� �������� ���������� ���������� How can we prove that an equilibrium QGP has been How can we prove that an equilibrium QGP has been created in central heavy- -ion collisions ?! ion collisions ?! created in central heavy 6 6

Signals of the phase transition: Signals of the phase transition: • Multi Multi- -strange particle enhancement in A+A strange particle enhancement in A+A • • Charm suppression Charm suppression • • Collective flow (v Collective flow (v 1 , v 2 ) 1 , v 2 ) • • Thermal dileptons Thermal dileptons • • Jet quenching and angular correlations Jet quenching and angular correlations • • High p High p T suppression of hadrons T suppression of hadrons • • Nonstatistical event by event fluctuations and correlations Nonstatistical event by event fluctuations and correlations • • ... ... • Experiment: measures Experiment: measures final hadrons and leptons final hadrons and leptons How to learn about How to learn about physics from data? physics from data? Compare with theory! Compare with theory! 7 7

Basic models for heavy- -ion collisions ion collisions Basic models for heavy • Statistical models: • Statistical models: basic assumption: system is described by a (grand) canonical ensemble of : system is described by a (grand) canonical ensemble of basic assumption non- -interacting fermions and bosons in interacting fermions and bosons in thermal and chemical equilibrium thermal and chemical equilibrium non -: : no dynamics] [ - no dynamics] [ • Ideal hydrodynamical models: • Ideal hydrodynamical models: basic assumption: conservation laws + equation of state; assumption of : conservation laws + equation of state; assumption of basic assumption local thermal and chemical equilibrium local thermal and chemical equilibrium -: : - [ - - simplified dynamics] simplified dynamics] [ • Transport models: • Transport models: based on transport theory of relativistic quantum many- based on transport theory of relativistic quantum many -body systems body systems - - Actual solutions: Monte Carlo simulations Monte Carlo simulations Actual solutions: +: full dynamics | -: : very complicated] [ +: full dynamics | - [ very complicated] � Microscopic transport models provide a unique � � � � � � � Microscopic transport models provide a unique dynamical dynamical description description of nonequilibrium nonequilibrium effects in heavy effects in heavy- -ion collisions ion collisions of 8 8

Semi- -classical BUU equation classical BUU equation Semi Boltzmann - -Uehling Uehling- -Uhlenbeck equation Uhlenbeck equation (non (non- -relativistic formulation) relativistic formulation) Boltzmann - propagation of particles in the propagation of particles in the self self- -generated Hartree generated Hartree- -Fock mean Fock mean- -field field - U(r,t) with an on potential U(r,t) potential with an on- -shell shell collision term: collision term: Ludwig Boltzmann � � � �         � � � � � � � ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ p f         + + + + ∇ ∇ ∇ ∇ − − − − ∇ ∇ ∇ ∇ ∇ ∇ ∇ ∇ = = = = f ( r , p , t ) f ( r , p , t ) U ( r , t ) f ( r , p , t ) collision term: � � � collision term: r r p         ∂ ∂ ∂ ∂ ∂ ∂ ∂ ∂ t m t eleastic and eleastic and coll inelastic reactions inelastic reactions � � f ( r , p , t ) is the single particle phase single particle phase- -space distribution function space distribution function is the - - probability to find the particle at position probability to find the particle at position r r with momentum with momentum p p at time at time t t � self � self- -generated generated Hartree Hartree- -Fock mean Fock mean- -field potential: field potential: � � � � � 1 ∑∫ ∑ ∑ ∑ ∫ ∫ ∫ 3 ′ ′ ′ ′ 3 ′ ′ ′ ′ ′ ′ ′ ′ = = − − + + U ( r , t ) = = d r d p V ( r − − r , t ) f ( r , p , t ) + + ( Fock term ) 3 � π π π π ( 2 ) β β β β occ � Collision term � 3+4 (let � for 1+2 � � � � � � Collision term for 1+2 3+4 (let‘ ‘s consider fermions) s consider fermions) : : � � � � σ σ σ σ 4 d ∫ ∫ ∫ ∫ ∫ ∫ ∫ ∫ 3 3 3 = = = = Ω Ω Ω Ω υ υ υ υ δ δ δ δ + + + + − − − − − − − − ⋅ ⋅ ⋅ ⋅ + + + + → → → → + + + + ⋅ ⋅ ⋅ ⋅ I d p d p d | | ( p p p p ) ( 1 2 3 4 ) P coll 2 3 12 1 2 3 4 3 ( 2 π π π π ) d Ω Ω Ω Ω Probability including Pauli blocking of fermions: Pauli blocking of fermions: 3 Probability including ∆ ∆ ∆ ∆ t 1 = = = = − − − − − − − − − − − − − − − − − − − − P f f ( 1 f )( 1 f ) f f ( 1 f )( 1 f ) 3 4 1 2 1 2 3 4 Gain term: 3+4 � � � 1+2 � � � Loss term: 1+2 � � � � � 3+4 � � � � � 1+2 3+4 υ υ 4 Gain term: 3+4 Loss term: 1+2 υ υ 2 12 9 9