Dileptons with a coarse-grained transport approach Hendrik van Hees Goethe University Frankfurt and FIAS July 19, 017 in collaboration with S. Endres, J. Weil, M. Bleicher Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 1 / 40
Outline 1 Electromagnetic probes Chiral symmetry and QCD phase diagram Electromagnetic radiation from hot/dense QCD matter Hadronic many-body theory Bulk-medium evolution with transport and coarse graining coarse-graining in transport models 3 Dileptons in heavy-ion collisions Dielectrons (SIS/HADES) Dimuons (SPS/NA60) Dielectrons at RHIC and LHC Dielectrons at FAIR/RHIC-BES 4 Signatures of the QCD-phase structure? 5 Conclusions and Outlook Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 / 40
Electromagnetic probes theory perspective Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 3 / 40
Hadron phenomenology and chiral symmetry in vacuum: Spontaneous breaking of chiral symmetry mass splitting of chiral partners qq-excitations of the QCD vacuum Energy (MeV) f1 (140) a1(160) f1(185) φ(0) f0(400-100) ρ (770) ω (78) P-S, V-A splitting in the physical vacuum π (140) Im Π V,A /(πs) [dim. less 0.08 0.06 0.04 0.0 V [τ > nπ ν τ A [τ > (n+1)π ν τ ρ(770) + cont. a 1 (160) + cont. 0 0 1 3 s [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 4 / 40
The QCD-phase diagram hot and dense matter: quarks and gluons close together highly energetic collisions deconfinement quarks and gluons relevant dof quark-gluon plasma still strongly interacting fast thermalization! T [GeV 0.5 quark-gluon plasma 0.0 RHIC qq = qq = 0 SPS 0.15 crit. point AGS 0. 0.05 hadron gas qq 0 SIS nuclei 0.0 µ N 1 st order qq 0 Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 5 / 40
The QCD-phase diagram at high temperature/density: restoration of chiral symmetry lattice QCD: T χ c T deconf c Mass mechanism of chiral restoration? two main theoretical ideas dropping masses : m had ψψ melting resonances : broadening of spectra through medium effects More theoretical question: realization of chiral symmetry in nature? Spectral Function Spectral Function "ρ" "ρ" Dropping Masses? Melting Resonances? "a 1 " "a 1 " pert. QCD pert. QCD Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
Electromagnetic probes in heavy-ion collisions γ,l ± : no strong interactions reflect whole history of collision: from pre-equilibrium phase from thermalized medium QGP and hot hadron gas from VM decays after thermal freezeout dn ee / dydm π o,η Dalitz-decays ρ,ω Φ DD J/Ψ Ψ l π,... ρ/ω γ e e + Drell-Yan Low- Intermediate- High-Mass Region > fm > 1 fm < 0.1 fm 0 1 3 4 5 mass [GeV/c Fig. by A. Drees γ Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 7 / 40
Electromagnetic probes from thermal source photon and dilepton thermal emission rates given by same electromagnetic-current-correlation function (J µ = f Q f ψ f γ µ ψ f ) McLerran-Toimela formula [MT85, GK91 q 0 dn γ d 4 x d 3 q = α em π g µν Im Π (ret) µν (q, u) f B (q u) q 0 = q dn e +e d 4 x d 4 q = g µν α Im 3q Π(ret) π3 µν (q, u) f B (q u) q =M e +e Lorentz covariant (dependent on four-velocity of fluid cell, u) q u = E cm : Doppler blue shift of q T spectra! to lowest order in α: 4παΠ µν Σ (γ) µν vector-meson dominance model: Σ γ µν = l + l -inv.-mass spectra in-med. spectral functions of vector mesons (ρ, ω, φ)! G ρ Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 8 / 40
Radiation from thermal QGP: q q annihilation General: McLerran-Toimela formula dn (MT) l + l d 4 x d 4 q = α L(M ) g 3π 3 M µν Im Π µν em,i (M, q )f B (q u) i enumerates partonic/hadronic sources of em. currents in-medium em. current-current correlation function Π µν em,i = i d 4 x exp(iq x )Θ(x 0 ) j µ em,i (x ), j ν em,i (0) i in QGP phase: q q annihilation hard-thermal-loop improved em. current-current correlator q γ γ iπ em,qgp = q Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 9 / 40
Hadronic many-body theory hadronic many-body theory (HMBT) for vector mesons [Ko et al, Chanfray et al, Herrmann et al, Rapp et al,... ππ interactions and baryonic excitations effective hadronic models, implementing symmetries parameters fixed from phenomenology (photon absorption at nucleons and nuclei, πn ρn ) evaluated at finite temperature and density self-energies mass shift and broadening in the medium ρ π B *, a 1, K 1,... ρ ρ ρ π N, K, π,... Baryons important, even at low net baryon density n B n B reason: n B +n B relevant (CP inv. of strong interactions) Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 / 40
Meson contributions 70 Im Σ ρ /m ρ [MeV 60 50 40 30 0 T=150MeV q=0.3gev ω sum a 1 K 1 h 1 π 0 f 1 30 sum Re Σ ρ /m ρ [MeV 0 0 ω K 1 a 1 0 30 0.0 0. 0.4 0.6 0.8 1.0 1. M [GeV [RG99 Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 11 / 40
In-medium spectral functions and baryon effects [RW99 baryon effects important large contribution to broadening of the peak responsible for most of the strength at small M Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 1 / 40
Dilepton rates: Hadron gas QGP in-medium hadron gas matches with QGP similar results also for γ rates quark-hadron duality? [Rap13 Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 13 / 40
Bulk-medium evolution Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 14 / 40
Bulk evolution with transport and coarse graining established transport models for bulk evolution e.g., UrQMD, GiBUU, BAMPS, (p)hsd,... solve Boltzmann equation for hadrons and/or partons dilemma: need medium-modified dilepton/photon emission rates usually available only in equilibrium QFT calculations ways out: use (ideal) hydrodynamics local thermal equilibrium use equilibrium rates use transport-hydro hybrid model: treat early stage with transport, then coarse grain switch to hydro switch back to transport (Cooper-Frye particlization ) here: UrQMD transport for entire bulk evolution use coarse graining in space-time cells extract T, µ B, µ π,... use equilibrium rates locally Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 15 / 40
Coarse-grained UrQMD (CGUrQMD) problem with medium modifications of spectral functions/interactions only available in equilibrium many-body QFT models use in-medium cross sections naively: double counting?!? way out: map transport to local-equilibrium fluid use ensemble of UrQMD runs with an equation of state space-time grid with t = 0. fm/c, x = 0.8 fm fit temperature, chemical potentials, flow-velocity field from anisotropic energy-momentum tensor [FMRS13 T µν = (ε + P )u µ u ν P g µν (P P )V µ V ν thermal rates from partonic/hadronic QFT become applicable here: extrapolated lattice QGP and Rapp-Wambach HMBT caveat: consistency between EoS, matter content of QFT model/urqmd! Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 16 / 40
Coarse-grained UrQMD (CGUrQMD) Temperature [MeV T c = 170 MeV; T > T c lattice EoS; T < T c HRG EoS 300 80 60 40 0 00 180 160 140 10 Lattice EoS (T =170 MeV) c Hadron Gas EoS (for µ =0) B 0 0 0 30 40 50 60 70 80 90 0 Energy density ε/ε Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 17 / 40 0
Coarse-grained UrQMD (CGUrQMD) pressure anisotropy (In-In collisions (NA60) at SIS) In+In @ 158 AGeV <dn ch /dη>=10 Central cell (x=y=z=0) 3 ) P P (GeV/fm Anisotropy parameter x Relaxation function r(x) 1-1 - -3 0 4 6 8 1 14 Time t [fm Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 18 / 40
Coarse-grained UrQMD (CGUrQMD) 0 /ρ B and ρ 0 ε/ε energy/baryon density T,µ B (for In+In @ SPS; NA60) central fluid cell! In+In @ 158 AGeV <dn ch /dη>=10 Central cell (x=y=z=0) Energy density ε/ε 0 Baryon density ρ/ρ 0 (a) [MeV B T and µ 500 400 300 Lattice EoS T µ B µ π Hadron Gas EoS In + In @ 158 AGeV <dn ch /dη>=10 Central cell (x=y=z=0) (b) 1 00-1 0-0 4 6 8 1 14 Time t [fm 0 0 4 6 8 1 14 Time t [fm Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 19 / 40
Coarse-grained UrQMD (CGUrQMD) energy (ε) and baryon (ρ) density profiles (for In+In@SPS; NA60) 0 and ρ/ρ 0 Energy and baryon density [ε/ε 10 Transverse density profiles In+In @ 158 AGeV 0 80 60 40 0 (a) t = 1fm: ε/ε 0 ρ/ρ 0 t = 3fm: ε/ε 0 x 5 ρ/ρ x 5 0 t = 5fm: ε/ε 0 x 8 ρ/ρ x 8 0 0-8 -6-4 - 0 4 6 8 x-axis [fm 0 and ρ/ρ 0 Energy and baryon density [ε/ε 10 0 80 60 40 0 0 Longitudinal density profiles In+In @ 158 AGeV (b) t = 1fm: ε/ε 0 ρ/ρ 0 t = 3fm: ε/ε 0 x 5 ρ/ρ x 5 0 t = 5fm: ε/ε 0 x 8 ρ/ρ x 8 0-8 -6-4 - 0 4 6 8 z-axis [fm Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 0 / 40
Dielectrons (SIS/HADES) Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 1 / 40
CGUrQMD: Ar+KCl (1.76 AGeV) (SIS/HADES) coarse-graining method works at low energies! UrQMD-medium evolution + RW-QFT rates -1 dn/dm [GeV/c 1/N(π 0 ) - -3-4 -5-6 Ar + KCl @ 1.76 AGeV HADES acceptance, 0.1 < p < 1.1 GeV/c e (a) Coarse-Graining Medium ρ Medium ω Multi π UrQMD π η φ ρ ω fo fo -7-8 -9 0 0. 0.4 0.6 0.8 1 M [GeV/c Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 / 40
CGUrQMD: Ar+KCl (1.76 AGeV) (SIS/HADES) dielectron spectra from Ar + KCl(1.76 AGeV) e + e (SIS/HADES) m t spectra M ee < 0.13 GeV UrQMD (a) Ar + KCl @ 1.76 AGeV πη /5 t [GeV/c dn/dm t ) 3/ )m 0 1-1 - -3 Coarse-Graining Medium ρ Medium ω Multi π φ ρ ω fo fo < 0.13 GeV/c M ee 1/(N(π -4-5 -6 0 0. 0.4 0.6 0.8 1 [GeV/c m t Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 3 / 40
CGUrQMD: Ar+KCl (1.76 AGeV) (SIS/HADES) dielectron spectra from Ar + KCl(1.76 AGeV) e + e (SIS/HADES) m t spectra 0.13 GeVM ee < 0.3 GeV /5 t [GeV/c - 0.13 < M ee < 0.30 GeV/c -3 (b) dn/dm t ) 3/ )m 0 1/(N(π -4-5 -6-7 -8 0 0. 0.4 0.6 0.8 1 [GeV/c m t Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 3 / 40
CGUrQMD: Ar+KCl (1.76 AGeV) (SIS/HADES) dielectron spectra from Ar + KCl(1.76 AGeV) e + e (SIS/HADES) m t spectra 0.3 GeVM ee < 0.45 GeV /5 t [GeV/c -3 0.30 < M ee < 0.45 GeV/c -4 (c) dn/dm t ) 3/ )m 0 1/(N(π -5-6 -7-8 -9 0. 0.4 0.6 0.8 1 1. [GeV/c m t Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 3 / 40
CGUrQMD: Ar+KCl (1.76 AGeV) (SIS/HADES) dielectron spectra from Ar + KCl(1.76 AGeV) e + e (SIS/HADES) m t spectra 0.45 GeVM ee < 0.65 GeV /5 t [GeV/c -4 0.45 < M ee < 0.65 GeV/c -5 (d) dn/dm t ) 3/ )m 0 1/(N(π -6-7 -8-9 - 0.4 0.6 0.8 1 1. 1.4 [GeV/c m t Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 3 / 40
CGUrQMD: Ar+KCl (1.76 AGeV) (SIS/HADES) dielectron spectra from Ar + KCl(1.76 AGeV) e + e (SIS/HADES) m t spectra M ee > 0.65 GeV /5 t [GeV/c -4 M ee > 0.65 GeV/c -5 (e) dn/dm t ) 3/ )m 0 1/(N(π -6-7 -8-9 - 0.6 0.8 1 1. 1.4 1.6 [GeV/c m t Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 3 / 40
CGUrQMD: Ar+KCl (1.76 AGeV) (SIS/HADES) dielectron spectra from Ar + KCl(1.76 AGeV) e + e (SIS/HADES) m t spectra rapidity spectrum (M ee < 0.13 GeV) ) dn/dy 0 1/N(π 1-1 - -3 (f) < 0.13 GeV/c M ee -4-5 -6-7 -0.5 0 0.5 1 1.5 Radpidity y Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 3 / 40
CGUrQMD: Au+Au (1.3 AGeV) (SIS/HADES) -1 dn/dm [GeV/c (1/N(π 0 )) - -3-4 -5-6 Au + Au @ 1.3 AGeV HADES acceptance, 0.1 < p < 1.1 GeV/c e (b) -7-8 -9 0 0. 0.4 0.6 0.8 1 M [GeV/c caveat: pp/np acceptance filter with single-e cut, p t < 0 MeV correct filter urgently needed! excellent agreement with preliminary HADES data Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 4 / 40
Dimuons (SPS/NA60) Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 5 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) -1 /dη) [0 MeV /dmdη)/(dn ch -5-6 -7 In+In @ 158 AGeV <dn ch /dη>=10, p > 0 GeV T HG-EoS + Lattice EoS In-medium ρ Non-thermal ρ QGP (Lattice) Multi π Sum (a) For comparison: Thermal ρ (no baryons) Perturb. qq µµ (dn -8-9 0 0. 0.4 0.6 0.8 1 1. 1.4 M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) higher IMR: provides averaged true temperature T 1.5 GeV M.4 GeV = 05-30 MeV clearly above T c 150-160 MeV (no blueshifts in the invariant-mass spectra!) -1 /dη) [0 MeV /dmdη)/(dn ch -6-7 -8 (b) µµ (dn -9-0.8 1 1. 1.4 1.6 1.8..4.6.8 M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) p T < 0. GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -7-6 -8-9 - (a) In+In @ 158 AGeV <dn ch /dη>=10 < 0. GeV In-medium ρ Non-thermal ρ QGP (Lattice) Multi π Sum 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV p T Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 0. GeV < p T < 0.4 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (b) 0. < p T < 0.4 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 0.4 GeV < p T < 0.6 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (c) 0.4 < p T < 0.6 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 0.6 GeV < p T < 0.8 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (d) 0.6 < p T < 0.8 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 0.8 GeV < p T < 1.0 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (e) 0.8 < p T < 1.0 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 1.0 GeV < p T < 1. GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (f) 1.0 < p T < 1. GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 1. GeV < p T < 1.4 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (a) 1. < p T < 1.4 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 1.4 GeV < p T < 1.6 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (b) 1.4 < p T < 1.6 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 1.6 GeV < p T < 1.8 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (c) 1.6 < p T < 1.8 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) 1.8 GeV < p T <.0 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (d) 1.8 < p T <.0 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10).0 GeV < p T <. GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (e).0 < p T <. GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10). GeV < p T <.4 GeV -1 /dη) [0 MeV /dmdη)/(dn ch µµ (dn -6-7 -8-9 - (f). < p T <.4 GeV 0 0. 0.4 0.6 0.8 1 1. 1.4 Invariant Mass M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 6 / 40
t CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) t - /dη) [GeV dη)/(dn /dm ch -4-5 -6 (a) In+In @ 158 AGeV HG-EoS + Lattice EoS <dn ch /dη>=10 0. < M < 0.4 GeV In-medium ρ Non-thermal ρ QGP (Lattice) Multi π Sum µµ )(dn (1/m -7-8 -9 0 0. 0.4 0.6 0.8 1 1. 1.4 1.6 1.8 m t -M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 7 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) t - t /dη) [GeV dη)/(dn /dm ch -4-5 -6 (b) 0.4 < M < 0.6 GeV µµ )(dn (1/m -7-8 -9 0 0. 0.4 0.6 0.8 1 1. 1.4 1.6 1.8 m t -M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 7 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) t - t /dη) [GeV dη)/(dn /dm ch -4-5 -6 (c) 0.6 < M < 0.9 GeV µµ )(dn (1/m -7-8 -9 0 0. 0.4 0.6 0.8 1 1. 1.4 1.6 1.8 m t -M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 7 / 40
CGUrQMD: In+In (158 AGeV) (SPS/NA60) dimuon spectra from In + In(158 AGeV) µ + µ (NA60) [EHWB15 min-bias data (dn ch /dy = 10) t - t /dη) [GeV dη)/(dn /dm ch -4-5 -6 (d) 1.0 < M < 1.4 GeV µµ )(dn (1/m -7-8 -9 0 0. 0.4 0.6 0.8 1 1. 1.4 1.6 1.8 m t -M [GeV Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 7 / 40
Dielectrons at RHIC and LHC Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 8 / 40
CGUrQMD: Au+Au ( s N N = 00 GeV) (RHIC/STAR) ) [1/(GeV/c dn/dm ee 1-1 Au+Au @ e T e p > 0. GeV/c η < 1, y STAR data < 1 ee s = 00 AGeV (0-% centr.) Coarse-grained Rapp in-med ρ Rapp in-med ω Multi-pion QGP (Lattice) UrQMD π 0 η ω (fo) ρ (fo) φ - -3 0 0. 0.4 0.6 0.8 1 1. 1.4 [GeV/c M ee Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 9 / 40
CGUrQMD: Au+Au ( s N N = 00 GeV) (RHIC/PHENIX) ) in PHENIX acc. [1/(GeV/c -1 - -3-4 Au+Au @ s = 00 AGeV (0-% centr.) e p > 0. GeV/c Coarse-grained UrQMD T e y < 1, Θ ee > 0.1 rad Rapp in-med ρ π 0 PHENIX HBD data Rapp in-med ω η Multi-pion ω (fo) QGP (Lattice) ρ (fo) φ dn/dm ee -5 0 0. 0.4 0.6 0.8 1 1. 1.4 [GeV/c M ee Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 30 / 40
CGUrQMD: Pb+Pb ( s N N =.76 + 5.5V ) (ALICE) Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 31 / 40
Dielectrons at RHIC-BES/FAIR/NICA Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 3 / 40
CGUrQMD: Au+Au (E lab = -35 AGeV) NB: also photon spectra [EHB16 Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 33 / 40
Signatures of the QCD-phase structure? Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 34 / 40
QCD phase structure from em. probes? hadronic observables like p T spectra: snapshot of the stage after kinetic freezeout particle abundancies: chemical freezeout em. probes: emitted during the whole medium evolution life time of the medium four-volume of the fireball use CGUrQMD to study system-size dependence study AA collisions for different A [EHWB15 excitation functions : systematics of l + l (and γ) emission vs. beam energy [EHB16, RH16 similar study in [GHR + 16 caveat: phase transition not really implemented!!! Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 35 / 40
Dilepton systematics in the beam-energy scan thermal-fireball model [RH16 beam-energy scan at RHIC and lower energies at future FAIR and NICA accelerators dilepton yield as fireball-lifetime clock 5 0 hadronic QGP sum sum (acc) 3.75 τ fb 0.3GeV < M < 0.7GeV 0 15 N l + l /Nch 6 15 5 5 τfb(fm/c) 0 0 snn (GeV) 0 Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 36 / 40
Conclusions and Outlook General ideas em. probes in-medium em. current-correlation function dual rates around T c (compatible with χ symmetry restoration) medium modifications of ρ, ω, φ importance of baryon-resonance interactions Application to dileptons in HICs Outlook coarse-grained transport (here: CGUrQMD) allows use of thermal-qft spectral VM functions applicable also at low collision energies allows use of thermal-qft models for dilepton rates successful description from SIS to RHIC energies consistent description of M and m T spectra! effective slope of M spectra (1.5 GeV < M < M J /ψ ) provides T beam-energy scan at RHIC and FAIR signature of phase transition? signature of cross-over vs. 1st order (or even critical endpoint)??? challenge: phase transition in (coarse-grained) transport??? Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 37 / 40
Bibliography I [EHB16 S. Endres, H. van Hees, M. Bleicher, Photon and dilepton production at the Facility for Proton and Anti-Proton Research and beam-energy scan at the Relativistic Heavy-Ion Collider using coarse-grained microscopic transport simulations, Phys. Rev. C 93 (016) 054901. http://dx.doi.org/.13/physrevc.93.054901 [EHWB15 S. Endres, H. van Hees, J. Weil, M. Bleicher, Dilepton production and reaction dynamics in heavy-ion collisions at SIS energies from coarse-grained transport simulations, Phys. Rev. C 9 (015) 014911. http://dx.doi.org/.13/physrevc.9.014911 [FMRS13 W. Florkowski, M. Martinez, R. Ryblewski, M. Strickland, Anisotropic hydrodynamics, Nucl. Phys. A 904-905 (013) 803c. http://dx.doi.org/.16/j.nuclphysa.013.0.138 Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 38 / 40
Bibliography II [GHR + 16 [GK91 [MT85 [Rap13 T. Galatyuk, P. M. Hohler, R. Rapp, F. Seck, J. Stroth, Thermal Dileptons from Coarse-Grained Transport as Fireball Probes at SIS Energies, Eur. Phys. J. A 5 (016) 131. http://dx.doi.org/.1140/epja/i016-16131-1 C. Gale, J. I. Kapusta, Vector dominance model at finite temperature, Nucl. Phys. B 357 (1991) 65. http://dx.doi.org/.16/0550-313(91)90459-b L. D. McLerran, T. Toimela, Photon and Dilepton Emission from the Quark-Gluon Plasma: Some General Considerations, Phys. Rev. D 31 (1985) 545. http://dx.doi.org/.13/physrevd.31.545 R. Rapp, Dilepton Spectroscopy of QCD Matter at Collider Energies, Adv. High Energy Phys. 013 (013) 14853. http://dx.doi.org/.1155/013/14853 Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 39 / 40
Bibliography III [RG99 R. Rapp, C. Gale, ρ properties in a hot meson gas, Phys. Rev. C 60 (1999) 04903. http://dx.doi.org/.13/physrevc.60.04903 [RH16 [RW99 R. Rapp, H. van Hees, Thermal Dileptons as Fireball Thermometer and Chronometer, Phys. Lett. B 753 (016) 586. http://dx.doi.org/.16/j.physletb.015.1.065 R. Rapp, J. Wambach, Low mass dileptons at the CERN-SPS: Evidence for chiral restoration?, Eur. Phys. J. A 6 (1999) 415. http://dx.doi.org/.07/s0500050364 Hendrik van Hees (GU Frankfurt/FIAS) Dileptons in coars-grained transport July 19, 017 40 / 40