HADES The Baryon-rich Side of the Phase Diagram Au+Au collisions at √sNN = 2.4 GeV Strangeness Production Flow and its Anisotropies Virtual Photon Emission Net-Proton Fluctuations Manuel Lorenz for the HADES Collaboration QM 2017 Chicago

The Baryon-rich Side of the Phase Diagram K. Fukushima HADES: Au+Au √sNN=2.4 GeV Large stopping and interpenetration times  Baryon dominated system system

The Baryon-rich Side of the Phase Diagram Virtual Photon Emission: Vector meson spectral functions modified by coupling to baryons Strangeness Production: Strong kinematical suppression of direct K- NNNYK+ √sNN= 2.55 GeV NNNNK+K- √sNN= 2.86 GeV Strong coupling of K- to baryons strangeness exchange reactions e.g. πYNK- Flow Anisotropies: Preferred out-of-plane emission due to shadowing Net-Proton Fluctuations: No Antiprotons, additional terms when correcting for volume fluctuations K. Fukushima HADES: Au+Au √sNN=2.4 GeV Large stopping and interpenetration times  Baryon dominated system system

The Baryon-rich Side of the Phase Diagram Virtual Photon Emission: Vector meson spectral functions modified by coupling to baryons Strangeness Production: Strong kinematical suppression of direct K- NNNYK+ √sNN= 2.55 GeV NNNNK+K- √sNN= 2.86 GeV Strong coupling of K- to baryons strangeness exchange reactions e.g. πYNK- Flow Anisotropies: Preferred out-of-plane emission due to shadowing Net-Proton Fluctuations: No Antiprotons, additional terms when correcting for volume fluctuations K. Fukushima HADES: Au+Au √sNN=2.4 GeV Large stopping and interpenetration times  Baryon dominated system system Clear hierarchy in hadron yields: p ≈ 100, π ≈ 10, K+ ≈ 10-2, K- ≈10-4

The Baryon-rich Side of the Phase Diagram K. Fukushima ©Hosan HADES: Au+Au √sNN=2.4 GeV Large stopping and interpenetration times  Baryon dominated system system Fast detector: up to 50 kHz trigger rate Large acceptance: Full azimuthal and polar angle coverage of Θ = 18° – 85° 2.1x109 events analyzed Clear hierarchy in hadron yields: p ≈ 100, π ≈ 10, K+ ≈ 10-2, K- ≈10-4

The Baryon-rich Side of the Phase Diagram Progress detector driven K. Fukushima ©Hosan HADES: Au+Au √sNN=2.4 GeV Large stopping and interpenetration times  Baryon dominated system system Fast detector: up to 50 kHz trigger rate Large acceptance: Full azimuthal and polar angle coverage of Θ = 18° – 85° 2.1x109 events analyzed Clear hierarchy in hadron yields: p ≈ 100, π ≈ 10, K+ ≈ 10-2, K- ≈10-4

The Baryon-rich Side of the Phase Diagram Progress detector driven K. Fukushima protons HADES: Au+Au √sNN=2.4 GeV Large stopping and interpenetration times  Baryon dominated system system Fast detector: 8-50 kHz trigger rate Large Acceptance: Full azimuthal and polar angle coverage of Θ = 18° – 85° 2.1x109 events analyzed Clear hierarchy in hadron yields: p ≈ 100, π ≈ 10, K+ ≈ 10-2, K- ≈10-4

The Baryon-rich Side of the Phase Diagram Progress detector driven pions K. Fukushima HADES: Au+Au √sNN=2.4 GeV Large stopping and interpenetration times  Baryon dominated system system Clear hierarchy in hadron yields: p ≈ 100, π ≈ 10, K+ ≈ 10-2, K- ≈10-4

The Baryon-rich Side of the Phase Diagram Progress detector driven K. Fukushima Λ HADES: Au+Au √sNN=2.4 GeV Large stopping and interpenetration times  Baryon dominated system system First measurement below NN-threshold Clear hierarchy in hadron yields: p ≈ 100, π ≈ 10, K+ ≈ 10-2, K- ≈10-4

Macroscopic Description of Hadron Production Particle production from a homogeneous source. Strangeness canonical ensemble Parameter: T, µB, Rc, R. Additional parameter to suppress strangeness needed (RC < Rv). Fits at low beam energies based on limited number of particle species. Comparison of absolute yield for different particle species And ratio data/model in the lower part

Macroscopic Description of Hadron Production THERMUS V2.3: S. Wheaton, J.Cleymans Comput.Phys.Commun.180:84-106,2009 Particle production from a homogeneous source. Strangeness canonical ensemble Parameter: T, µB, Rc, R. Additional parameter to suppress strangeness needed (RC < Rv). Fits at low beam energies based on limited number of particle species. Au+Au 0-20% most central Comparison of absolute yield for different particle species And ratio data/model in the lower part

Macroscopic Description of Hadron Production THERMUS V2.3: S. Wheaton, J.Cleymans Comput.Phys.Commun.180:84-106,2009 Particle production from a homogeneous source. Strangeness canonical ensemble Parameter: T, µB, Rc, R. Additional parameter to suppress strangeness needed (RC < Rv). Fits at low beam energies based on limited number of particle species. Au+Au 0-20% most central Comparison of absolute yield for different particle species And ratio data/model in the lower part Hadron yields described by 4 parameters (T, µB, R, Rc) Matter formed?

(Sub-threshold) Strangeness Production

(Sub-threshold) Strangeness Production Kaons and antikaons show different slopes

(Sub-threshold) Strangeness Production KaoS: Phys.Rev. C75 (2007) 024906 “Later freeze-out of K- compared to K+, due to coupling to baryons and strangeness exchange reactions ??” Kaons and antikaons show different slopes

(Sub-threshold) Strangeness Production Φ/K- ratio constant at high energies Prog.Part.Nucl.Phys. 66 (2011) 834-879 Important phi over K-!

(Sub-threshold) Strangeness Production Increased in Au+Au collisions at low energies  25% of K- result from Φ decays! Prog.Part.Nucl.Phys. 66 (2011) 834-879

(Sub-threshold) Strangeness Production Increased in Au+Au collisions at low energies  25% of K- result from Φ decays! Φ feed-down can explain lower inverse slope parameter of K- spectrum (Teff = 84 ± 6 MeV) in comparison to the one of K+ (Teff = 104 ± 1 MeV) Prog.Part.Nucl.Phys. 66 (2011) 834-879

(Sub-threshold) Strangeness Production Increased in Au+Au collisions at low energies  25% of K- result from Φ decays! Φ feed-down can explain lower inverse slope parameter of K- spectrum (Teff = 84 ± 6 MeV) in comparison to the one of K+ (Teff = 104 ± 1 MeV) No indication for sequential K+K- freeze-out if K- spectrum is corrected for feed-down. Prog.Part.Nucl.Phys. 66 (2011) 834-879

(Sub-Threshold) Strangeness Production: the Complete Picture - Strange particle yields rise stronger than linear with <Apart> (M ~ <Apart>α) - Universal <Apart> dependence of strangeness production  Hierarchy in production threshold not reflected NNYK+ √sNN= 2.55 GeV NNNNK+K- √sNN= 2.86 GeV  Supports assumption that the production yields reflect matter properties

(Sub-Threshold) Strangeness Production: the Complete Picture - Strange particle yields rise stronger than linear with <Apart> (M ~ <Apart>α) - Universal <Apart> dependence of strangeness production  Hierarchy in production threshold not reflected NNYK+ √sNN= 2.55 GeV NNNNK+K- √sNN= 2.86 GeV  Supports assumption that the production yields reflect matter properties More: Parallel Session 7.1 Heidi Schuldes Wednesday 8 Feb 2017, 14:00

Flow and its Anisotropies Progress detector driven K. Fukushima

Flow and its Anisotropies Progress detector driven arXiv:1701.07065 K. Fukushima Extraction of kinetic freeze-out parameters by blast wave fit to hadron spectra. Tkin=62±10 MeV, <βr>=0.36±0.04 Λ and ϕ fall out of the trend. Parameter follow the trend of the world data.

Flow and its Anisotropies Progress detector driven arXiv:1701.07065 K. Fukushima Extraction of kinetic freeze-out parameters by blast wave fit to hadron spectra. Tkin=62±10 MeV, <βr>=0.36±0.04 Λ and ϕ fall out of the trend. Parameter follow the trend of the world data. The full story including v1,v2 of charged hadrons: Parallel Session 7.1, B. Kardan (talk given by C. Blume) Wednesday 8 Feb 2017, 14:40

Virtual Photon Emission Progress detector driven K. Fukushima

Virtual Photon Emission First measurement of e+e- for a heavy system in this energy regime. Normalized to the number of π0. Strong excess yield (0.15<M<0.7 GeV/c2) above e+e- cocktail components of meson decays at freeze-out and elementary baryonic reference observed.  Medium radiation Progress detector driven K. Fukushima

Virtual Photon Emission First measurement of e+e- for a heavy system in this energy regime. Normalized to the number of π0. Strong excess yield (0.15<M<0.7 GeV/c2) above e+e- cocktail components of meson decays at freeze-out and elementary baryonic reference observed.  Medium radiation Isolation of the excess by subtracting the elementary reference and the η-contribution. Acceptance corrected excess yield. Progress detector driven K. Fukushima

Virtual Photon Emission First measurement of e+e- for a heavy system in this energy regime. Normalized to the number of π0. Strong excess yield (0.15<M<0.7 GeV/c2) above e+e- cocktail components of meson decays at freeze-out and elementary baryonic reference observed.  Medium radiation Isolation of the excess by subtracting the elementary reference and the η-contribution. Acceptance corrected excess yield. Exponentially falling spectrum,  extraction of source temperature Progress detector driven K. Fukushima

Centrality Dependence of Virtual Photon Emission Dileptons: 0.3<M<0.7 GeV/c2 K. Fukushima α = 1.37 ± 0.18

Centrality Dependence of Virtual Photon Emission Dileptons: 0.3<M<0.7 GeV/c2 Strange Particles K. Fukushima α = 1.37 ± 0.18 Similar <Apart> dependence!

Centrality Dependence of Virtual Photon Emission Dileptons: 0.3<M<0.7 GeV/c2 Strange Particles K. Fukushima α = 1.37 ± 0.18 Similar <Apart> dependence! More: Parallel Session 1.3, Tetyana Galatyuk,Tuesday 7 Feb 2017, 8:50

(Net)-Proton Number Fluctuations Progress detector driven K. Fukushima

(Net)-Proton Number Fluctuations Things to consider: Phase space region, not too big not too small (No spectators, and check against Poisson limit). Extracted moments must be corrected for detector response. Two methods tested and validated with simulations. Volume number fluctuations for a given centrality selection, no antiprotons, no terms cancel! Various effects and their impact on the corrected moments systematically studied. Progress detector driven K. Fukushima

(Net)-Proton Number Fluctuations Progress detector driven K. Fukushima

(Net)-Proton Number Fluctuations Progress detector driven K. Fukushima Get the full story: Parallel Session 8.1, Romain Holzmann, Wednesday 8 Feb 2017, 17:10

Summary Tchem=68±2 MeV extracted from statistical model fit. No indication for sequential K+K- freeze-out when correcting for ϕ feed-down, common rise of strange hadron multiplicities with <Apart>. Parallel Session 7.1, H. Schuldes 8 Feb 2017, 14:00 Tkin=62±10 MeV and <βr>=0.36±0.04 extracted from blast wave fit. Parallel Session 7.1, B. Kardan (talk given by C. Blume) 8 Feb 2017, 14:40 Strong e+e- excess over reference, exponentially falling spectrum, extracted source temperature Tee=71±4 MeV, similar rise with <Apart> as observed for strange hadrons. Parallel Session 1.3, T. Galatyuk 7 Feb 2017, 8:50 First attempt of extracting fluctuations (corrections!) of net-proton distribution from data at low √s, continuing the excitation function measured by STAR. Parallel Session 8.1, R. Holzmann 8 Feb 2017, 17:10 Investigations on direct photons. Poster Session, C. Deveaux 6 Feb 2017, 16:00

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